| Message ID | 20210519074934.20712-3-quan@os.amperecomputing.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | Add Aspeed SSIF BMC driver | expand |
On Wed, May 19, 2021 at 02:49:29PM +0700, Quan Nguyen wrote: > The SMBus system interface (SSIF) IPMI BMC driver can be used to perform > in-band IPMI communication with their host in management (BMC) side. > > Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com> > --- > v3: > + Removed redundant license info [Joel] > + Switched to use traditional if-else [Joel] > + Removed unused ssif_bmc_ioctl() [Joel] > + Made handle_request()/complete_response() to return void [Joel] > + Refactored send_ssif_bmc_response()/receive_ssif_bmc_request() [Corey] > + Removed mutex [Corey] > + Use spin_lock/unlock_irqsave/restore in callback [Corey] > + Removed the unnecessary memset [Corey] > + Switch to use dev_err() [Corey] > > v2: > + Fixed compiling error with COMPILE_TEST for arc > > drivers/char/ipmi/Kconfig | 11 + > drivers/char/ipmi/Makefile | 1 + > drivers/char/ipmi/ssif_bmc.c | 605 +++++++++++++++++++++++++++++++++++ > drivers/char/ipmi/ssif_bmc.h | 93 ++++++ > 4 files changed, 710 insertions(+) > create mode 100644 drivers/char/ipmi/ssif_bmc.c > create mode 100644 drivers/char/ipmi/ssif_bmc.h > > diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig > index 07847d9a459a..ad5c5161bcd6 100644 > --- a/drivers/char/ipmi/Kconfig > +++ b/drivers/char/ipmi/Kconfig > @@ -133,6 +133,17 @@ config ASPEED_BT_IPMI_BMC > found on Aspeed SOCs (AST2400 and AST2500). The driver > implements the BMC side of the BT interface. > > +config SSIF_IPMI_BMC > + tristate "SSIF IPMI BMC driver" > + select I2C > + select I2C_SLAVE > + help > + This enables the IPMI SMBus system interface (SSIF) at the > + management (BMC) side. > + > + The driver implements the BMC side of the SMBus system > + interface (SSIF). > + > config IPMB_DEVICE_INTERFACE > tristate 'IPMB Interface handler' > depends on I2C > diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile > index 0822adc2ec41..d04a214d74c4 100644 > --- a/drivers/char/ipmi/Makefile > +++ b/drivers/char/ipmi/Makefile > @@ -27,3 +27,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o > obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o > obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o > obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o > +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o > diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c > new file mode 100644 > index 000000000000..d0ea7059b1db > --- /dev/null > +++ b/drivers/char/ipmi/ssif_bmc.c > @@ -0,0 +1,605 @@ > +// SPDX-License-Identifier: GPL-2.0+ > +/* > + * The driver for BMC side of SSIF interface > + * > + * Copyright (c) 2021, Ampere Computing LLC > + * > + */ > + > +#include <linux/i2c.h> > +#include <linux/miscdevice.h> > +#include <linux/module.h> > +#include <linux/of.h> > +#include <linux/platform_device.h> > +#include <linux/poll.h> > +#include <linux/sched.h> > +#include <linux/mutex.h> > +#include <linux/spinlock.h> > + > +#include "ssif_bmc.h" > + > +/* Handle SSIF message that will be sent to user */ > +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + struct ssif_msg msg; > + unsigned long flags; > + ssize_t ret; > + > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + while (!ssif_bmc->request_available) { > + if (file->f_flags & O_NONBLOCK) { There is no real need to check this under the lock. It would simplify the end of this function if you checked this outside the lock. > + ret = -EAGAIN; > + goto out_unlock; > + } > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + ret = wait_event_interruptible(ssif_bmc->wait_queue, > + ssif_bmc->request_available); > + if (ret) > + return ret; > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + } > + > + count = min_t(ssize_t, ssif_msg_len(&ssif_bmc->request), > + min_t(ssize_t, sizeof(struct ssif_msg), count)); Just curious, what happens if userland supplies a buffer that is too small? Is data lost? In that case, I would think returning an error here would be the better thing, as opposed to silently truncating the message. > + memcpy(&msg, &ssif_bmc->request, count); > + ssif_bmc->request_available = false; > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + > + ret = copy_to_user(buf, &msg, count); > + goto out; > + > +out_unlock: > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > +out: > + return (ret < 0) ? ret : count; > +} > + > +/* Handle SSIF message that is written by user */ > +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count, > + loff_t *ppos) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + struct ssif_msg msg; > + unsigned long flags; > + ssize_t ret; > + > + if (count > sizeof(struct ssif_msg)) > + return -EINVAL; > + > + ret = copy_from_user(&msg, buf, count); > + if (ret) > + return ret; > + > + if (!msg.len || count < ssif_msg_len(&msg)) > + return -EINVAL; > + > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + while (ssif_bmc->response_in_progress) { > + if (file->f_flags & O_NONBLOCK) { Same comment as O_NONBLOCK before. > + ret = -EAGAIN; > + goto out_unlock; > + } > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + ret = wait_event_interruptible(ssif_bmc->wait_queue, > + !ssif_bmc->response_in_progress); > + if (ret) > + goto out; > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + } > + > + memcpy(&ssif_bmc->response, &msg, count); > + ssif_bmc->is_singlepart_read = (ssif_msg_len(&msg) <= MAX_PAYLOAD_PER_TRANSACTION + 1); > + ssif_bmc->response_in_progress = true; > + if (ssif_bmc->set_ssif_bmc_status) > + ssif_bmc->set_ssif_bmc_status(ssif_bmc, SSIF_BMC_READY); > + > +out_unlock: > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + > +out: > + return (ret < 0) ? ret : count; > +} > + > +static int ssif_bmc_open(struct inode *inode, struct file *file) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + int ret = 0; > + > + spin_lock_irq(&ssif_bmc->lock); > + if (!ssif_bmc->running) > + ssif_bmc->running = 1; > + else > + ret = -EBUSY; > + spin_unlock_irq(&ssif_bmc->lock); > + > + return ret; > +} > + > +static unsigned int ssif_bmc_poll(struct file *file, poll_table *wait) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + unsigned int mask = 0; > + > + poll_wait(file, &ssif_bmc->wait_queue, wait); > + > + spin_lock_irq(&ssif_bmc->lock); > + /* > + * The request message is now available so userspace application can > + * get the request > + */ > + if (ssif_bmc->request_available) > + mask |= POLLIN; > + > + spin_unlock_irq(&ssif_bmc->lock); > + > + return mask; > +} > + > +static int ssif_bmc_release(struct inode *inode, struct file *file) > +{ > + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); > + > + spin_lock_irq(&ssif_bmc->lock); > + ssif_bmc->running = 0; > + spin_unlock_irq(&ssif_bmc->lock); > + > + return 0; > +} > + > +/* > + * System calls to device interface for user apps > + */ > +static const struct file_operations ssif_bmc_fops = { > + .owner = THIS_MODULE, > + .open = ssif_bmc_open, > + .read = ssif_bmc_read, > + .write = ssif_bmc_write, > + .release = ssif_bmc_release, > + .poll = ssif_bmc_poll, > +}; > + > +/* Called with ssif_bmc->lock held. */ > +static void handle_request(struct ssif_bmc_ctx *ssif_bmc) > +{ > + if (ssif_bmc->set_ssif_bmc_status) > + ssif_bmc->set_ssif_bmc_status(ssif_bmc, SSIF_BMC_BUSY); > + > + /* Request message is available to process */ > + ssif_bmc->request_available = true; > + /* > + * This is the new READ request. > + */ > + wake_up_all(&ssif_bmc->wait_queue); > +} > + > +/* Called with ssif_bmc->lock held. */ > +static void complete_response(struct ssif_bmc_ctx *ssif_bmc) > +{ > + /* Invalidate response in buffer to denote it having been sent. */ > + ssif_bmc->response.len = 0; > + ssif_bmc->response_in_progress = false; > + ssif_bmc->nbytes_processed = 0; > + ssif_bmc->remain_len = 0; > + wake_up_all(&ssif_bmc->wait_queue); > +} > + > +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + u8 response_len = 0; > + int idx = 0; > + u8 data_len; > + > + data_len = ssif_bmc->response.len; > + switch (ssif_bmc->smbus_cmd) { > + case SSIF_IPMI_MULTIPART_READ_START: > + /* > + * Read Start length is 32 bytes. > + * Read Start transfer first 30 bytes of IPMI response > + * and 2 special code 0x00, 0x01. > + */ > + *val = MAX_PAYLOAD_PER_TRANSACTION; > + ssif_bmc->remain_len = data_len - MAX_IPMI_DATA_PER_START_TRANSACTION; > + ssif_bmc->block_num = 0; > + > + ssif_bmc->response_buf[idx++] = 0x00; /* Start Flag */ > + ssif_bmc->response_buf[idx++] = 0x01; /* Start Flag */ > + ssif_bmc->response_buf[idx++] = ssif_bmc->response.netfn_lun; > + ssif_bmc->response_buf[idx++] = ssif_bmc->response.cmd; > + ssif_bmc->response_buf[idx++] = ssif_bmc->response.payload[0]; > + > + response_len = MAX_PAYLOAD_PER_TRANSACTION - idx; > + > + memcpy(&ssif_bmc->response_buf[idx], &ssif_bmc->response.payload[1], > + response_len); > + break; > + > + case SSIF_IPMI_MULTIPART_READ_MIDDLE: > + /* > + * IPMI READ Middle or READ End messages can carry up to 31 bytes > + * IPMI data plus block number byte. > + */ > + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) { > + /* > + * This is READ End message > + * Return length is the remaining response data length > + * plus block number > + * Block number 0xFF is to indicate this is last message > + * > + */ > + *val = ssif_bmc->remain_len + 1; > + ssif_bmc->block_num = 0xFF; > + ssif_bmc->response_buf[idx++] = ssif_bmc->block_num; > + response_len = ssif_bmc->remain_len; > + /* Clean the buffer */ > + memset(&ssif_bmc->response_buf[idx], 0, MAX_PAYLOAD_PER_TRANSACTION - idx); > + } else { > + /* > + * This is READ Middle message > + * Response length is the maximum SMBUS transfer length > + * Block number byte is incremented > + * Return length is maximum SMBUS transfer length > + */ > + *val = MAX_PAYLOAD_PER_TRANSACTION; > + ssif_bmc->remain_len -= MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; > + response_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; > + ssif_bmc->response_buf[idx++] = ssif_bmc->block_num; > + ssif_bmc->block_num++; > + } > + > + memcpy(&ssif_bmc->response_buf[idx], > + ssif_bmc->response.payload + 1 + ssif_bmc->nbytes_processed, > + response_len); > + break; > + > + default: > + /* Do not expect to go to this case */ > + dev_err(&ssif_bmc->client->dev, > + "Error: Unexpected SMBus command received 0x%x\n", ssif_bmc->smbus_cmd); > + break; > + } > + > + ssif_bmc->nbytes_processed += response_len; > +} > + > +/* Process the IPMI response that will be read by master */ > +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + u8 *buf; > + u8 pec_len, addr, len; > + u8 pec = 0; > + > + pec_len = ssif_bmc->pec_support ? 1 : 0; > + /* PEC - Start Read Address */ > + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); > + pec = i2c_smbus_pec(pec, &addr, 1); > + /* PEC - SSIF Command */ > + pec = i2c_smbus_pec(pec, &ssif_bmc->smbus_cmd, 1); > + /* PEC - Restart Write Address */ > + addr = addr | 0x01; > + pec = i2c_smbus_pec(pec, &addr, 1); > + > + if (ssif_bmc->is_singlepart_read) { > + /* Single-part Read processing */ > + buf = (u8 *)&ssif_bmc->response; > + > + if (ssif_bmc->response.len && ssif_bmc->msg_idx < ssif_bmc->response.len) { > + ssif_bmc->msg_idx++; > + *val = buf[ssif_bmc->msg_idx]; > + } else if (ssif_bmc->response.len && ssif_bmc->msg_idx == ssif_bmc->response.len) { > + ssif_bmc->msg_idx++; > + *val = i2c_smbus_pec(pec, buf, ssif_msg_len(&ssif_bmc->response)); > + } else { > + *val = 0; > + } > + /* Invalidate response buffer to denote it is sent */ > + if (ssif_bmc->msg_idx + 1 >= (ssif_msg_len(&ssif_bmc->response) + pec_len)) > + complete_response(ssif_bmc); > + } else { > + /* Multi-part Read processing */ > + switch (ssif_bmc->smbus_cmd) { > + case SSIF_IPMI_MULTIPART_READ_START: > + case SSIF_IPMI_MULTIPART_READ_MIDDLE: > + buf = (u8 *)&ssif_bmc->response_buf; > + *val = buf[ssif_bmc->msg_idx]; > + ssif_bmc->msg_idx++; > + break; > + default: > + /* Do not expect to go to this case */ > + dev_err(&ssif_bmc->client->dev, > + "Error: Unexpected SMBus command received 0x%x\n", > + ssif_bmc->smbus_cmd); > + break; > + } > + len = (ssif_bmc->block_num == 0xFF) ? > + ssif_bmc->remain_len + 1 : MAX_PAYLOAD_PER_TRANSACTION; > + if (ssif_bmc->msg_idx == (len + 1)) { > + pec = i2c_smbus_pec(pec, &len, 1); > + *val = i2c_smbus_pec(pec, ssif_bmc->response_buf, len); > + } > + /* Invalidate response buffer to denote last response is sent */ > + if (ssif_bmc->block_num == 0xFF && > + ssif_bmc->msg_idx > (ssif_bmc->remain_len + pec_len)) { > + complete_response(ssif_bmc); > + } > + } > +} > + > +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + u8 *buf; > + u8 smbus_cmd; > + > + buf = (u8 *)&ssif_bmc->request; > + if (ssif_bmc->msg_idx >= sizeof(struct ssif_msg)) Shouldn't you abort the message if you get too much data? Otherwise you get silent truncation. > + return; > + > + smbus_cmd = ssif_bmc->smbus_cmd; > + switch (smbus_cmd) { > + case SSIF_IPMI_SINGLEPART_WRITE: > + /* Single-part write */ > + buf[ssif_bmc->msg_idx - 1] = *val; > + ssif_bmc->msg_idx++; > + > + break; Generally you put the space after the break, not before. You did this right before, but didn't from here down in the file. > + case SSIF_IPMI_MULTIPART_WRITE_START: > + /* Reset length to zero */ > + if (ssif_bmc->msg_idx == 1) > + ssif_bmc->request.len = 0; What happens if you get this and you are in the middle of a message? > + > + fallthrough; > + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: > + case SSIF_IPMI_MULTIPART_WRITE_END: What happens if you get these and you are not in a message? > + /* Multi-part write, 2nd byte received is length */ > + if (ssif_bmc->msg_idx == 1) { > + ssif_bmc->request.len += *val; > + ssif_bmc->recv_len = *val; > + } else { > + buf[ssif_bmc->msg_idx - 1 + > + ssif_bmc->request.len - ssif_bmc->recv_len] = *val; > + } > + > + ssif_bmc->msg_idx++; > + > + break; > + default: > + /* Do not expect to go to this case */ > + dev_err(&ssif_bmc->client->dev, > + "Error: Unexpected SMBus command received 0x%x\n", ssif_bmc->smbus_cmd); > + break; > + } > +} > + > +static bool validate_pec(struct ssif_bmc_ctx *ssif_bmc) > +{ > + u8 rpec = 0, cpec = 0; > + bool ret = true; > + u8 addr, index; > + u8 *buf; > + > + buf = (u8 *)&ssif_bmc->request; > + switch (ssif_bmc->smbus_cmd) { > + case SSIF_IPMI_SINGLEPART_WRITE: > + if ((ssif_bmc->msg_idx - 1) == ssif_msg_len(&ssif_bmc->request)) { > + /* PEC is not included */ > + ssif_bmc->pec_support = false; > + return true; > + } > + > + if ((ssif_bmc->msg_idx - 1) != (ssif_msg_len(&ssif_bmc->request) + 1)) > + goto error; > + > + /* PEC is included */ > + ssif_bmc->pec_support = true; > + rpec = buf[ssif_bmc->msg_idx - 2]; > + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); > + cpec = i2c_smbus_pec(cpec, &addr, 1); > + cpec = i2c_smbus_pec(cpec, &ssif_bmc->smbus_cmd, 1); > + cpec = i2c_smbus_pec(cpec, buf, ssif_msg_len(&ssif_bmc->request)); > + if (rpec != cpec) { > + dev_err(&ssif_bmc->client->dev, "Bad PEC 0x%02x vs. 0x%02x\n", rpec, cpec); > + ret = false; > + } > + > + break; > + case SSIF_IPMI_MULTIPART_WRITE_START: > + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: > + case SSIF_IPMI_MULTIPART_WRITE_END: > + index = ssif_bmc->request.len - ssif_bmc->recv_len; > + if ((ssif_bmc->msg_idx - 1 + index) == ssif_msg_len(&ssif_bmc->request)) { > + /* PEC is not included */ > + ssif_bmc->pec_support = false; > + return true; > + } > + > + if ((ssif_bmc->msg_idx - 1 + index) != (ssif_msg_len(&ssif_bmc->request) + 1)) > + goto error; > + > + /* PEC is included */ > + ssif_bmc->pec_support = true; > + rpec = buf[ssif_bmc->msg_idx - 2 + index]; > + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); > + cpec = i2c_smbus_pec(cpec, &addr, 1); > + cpec = i2c_smbus_pec(cpec, &ssif_bmc->smbus_cmd, 1); > + cpec = i2c_smbus_pec(cpec, &ssif_bmc->recv_len, 1); > + /* As SMBus specification does not allow the length > + * (byte count) in the Write-Block protocol to be zero. > + * Therefore, it is illegal to have the last Middle > + * transaction in the sequence carry 32-bytes and have > + * a length of ‘0’ in the End transaction. > + * But some users may try to use this way and we should > + * prevent ssif_bmc driver broken in this case. > + */ > + if (ssif_bmc->recv_len != 0) > + cpec = i2c_smbus_pec(cpec, buf + 1 + index, ssif_bmc->recv_len); > + > + if (rpec != cpec) { > + dev_err(&ssif_bmc->client->dev, "Bad PEC 0x%02x vs. 0x%02x\n", rpec, cpec); > + ret = false; > + } > + > + break; > + default: > + break; > + } > + > + return ret; > +error: > + /* Do not expect to go to this case */ > + dev_err(&ssif_bmc->client->dev, > + "Error: Unexpected length received %d\n", ssif_msg_len(&ssif_bmc->request)); > + > + return false; > +} > + > +static void complete_write_received(struct ssif_bmc_ctx *ssif_bmc) > +{ > + u8 cmd = ssif_bmc->smbus_cmd; > + > + /* A BMC that receives an invalid PEC shall drop the data for the write > + * transaction and any further transactions (read or write) until > + * the next valid read or write Start transaction is received > + */ > + if (!validate_pec(ssif_bmc)) { > + dev_err(&ssif_bmc->client->dev, "Received invalid PEC\n"); > + return; > + } > + > + if (cmd == SSIF_IPMI_SINGLEPART_WRITE || cmd == SSIF_IPMI_MULTIPART_WRITE_END) > + handle_request(ssif_bmc); > +} > + > +static void initialize_transfer(struct ssif_bmc_ctx *ssif_bmc, u8 *val) > +{ > + /* SMBUS command can vary (single or multi-part) */ > + ssif_bmc->smbus_cmd = *val; > + ssif_bmc->msg_idx++; > + > + if (ssif_bmc->smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE || > + ssif_bmc->smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_START) { > + /* > + * The response can be delayed in BMC causing host SSIF driver > + * to timeout and send a new request once BMC slave is ready. > + * In that case check for pending response and clear it > + */ > + if (ssif_bmc->response_in_progress) { > + dev_err(&ssif_bmc->client->dev, > + "Warn: SSIF new request with pending response"); > + complete_response(ssif_bmc); > + } > + } else if (unlikely(ssif_bmc->smbus_cmd != SSIF_IPMI_SINGLEPART_READ && > + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_WRITE_MIDDLE && > + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_WRITE_END && > + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_READ_START && > + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_READ_MIDDLE)) { > + /* Unknown command, clear it */ > + dev_err(&ssif_bmc->client->dev, "Warn: Unknown SMBus command"); > + complete_response(ssif_bmc); > + } > +} > + > +/* > + * Callback function to handle I2C slave events > + */ > +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val) > +{ > + unsigned long flags; > + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client); > + > + spin_lock_irqsave(&ssif_bmc->lock, flags); > + > + /* I2C Event Handler: > + * I2C_SLAVE_READ_REQUESTED 0x0 > + * I2C_SLAVE_WRITE_REQUESTED 0x1 > + * I2C_SLAVE_READ_PROCESSED 0x2 > + * I2C_SLAVE_WRITE_RECEIVED 0x3 > + * I2C_SLAVE_STOP 0x4 > + */ > + switch (event) { > + case I2C_SLAVE_READ_REQUESTED: > + ssif_bmc->msg_idx = 0; > + if (ssif_bmc->is_singlepart_read) > + *val = ssif_bmc->response.len; > + else > + set_multipart_response_buffer(ssif_bmc, val); > + break; > + > + case I2C_SLAVE_WRITE_REQUESTED: > + ssif_bmc->msg_idx = 0; > + break; > + > + case I2C_SLAVE_READ_PROCESSED: > + handle_read_processed(ssif_bmc, val); > + break; > + > + case I2C_SLAVE_WRITE_RECEIVED: > + if (ssif_bmc->msg_idx) > + handle_write_received(ssif_bmc, val); > + else > + initialize_transfer(ssif_bmc, val); > + > + break; > + > + case I2C_SLAVE_STOP: > + if (ssif_bmc->last_event == I2C_SLAVE_WRITE_RECEIVED) > + complete_write_received(ssif_bmc); > + /* Reset message index */ > + ssif_bmc->msg_idx = 0; > + break; > + > + default: > + break; > + } > + ssif_bmc->last_event = event; > + spin_unlock_irqrestore(&ssif_bmc->lock, flags); > + > + return 0; > +} > + > +struct ssif_bmc_ctx *ssif_bmc_alloc(struct i2c_client *client, int sizeof_priv) > +{ > + struct ssif_bmc_ctx *ssif_bmc; > + int ret; > + > + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc) + sizeof_priv, GFP_KERNEL); > + if (!ssif_bmc) > + return ERR_PTR(-ENOMEM); > + > + spin_lock_init(&ssif_bmc->lock); > + > + init_waitqueue_head(&ssif_bmc->wait_queue); > + ssif_bmc->request_available = false; > + ssif_bmc->response_in_progress = false; > + > + /* Register misc device interface */ > + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR; > + ssif_bmc->miscdev.name = DEVICE_NAME; > + ssif_bmc->miscdev.fops = &ssif_bmc_fops; > + ssif_bmc->miscdev.parent = &client->dev; > + ret = misc_register(&ssif_bmc->miscdev); > + if (ret) > + goto out; > + > + ssif_bmc->client = client; > + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE; > + > + /* Register I2C slave */ > + i2c_set_clientdata(client, ssif_bmc); > + ret = i2c_slave_register(client, ssif_bmc_cb); > + if (ret) { > + misc_deregister(&ssif_bmc->miscdev); > + goto out; > + } > + > + return ssif_bmc; > + > +out: > + devm_kfree(&client->dev, ssif_bmc); > + return ERR_PTR(ret); > +} > +EXPORT_SYMBOL(ssif_bmc_alloc); > + > +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>"); > +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>"); > +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface."); > +MODULE_LICENSE("GPL v2"); > diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h > new file mode 100644 > index 000000000000..eab540061f14 > --- /dev/null > +++ b/drivers/char/ipmi/ssif_bmc.h > @@ -0,0 +1,93 @@ > +/* SPDX-License-Identifier: GPL-2.0+ */ > +/* > + * The driver for BMC side of SSIF interface > + * > + * Copyright (c) 2021, Ampere Computing LLC > + * > + * This program is free software; you can redistribute it and/or > + * modify it under the terms of the GNU General Public License as > + * published by the Free Software Foundation; either version 2 of > + * the License, or (at your option) any later version. > + * > + * This program is distributed in the hope that it will be useful, > + * but WITHOUT ANY WARRANTY; without even the implied warranty of > + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the > + * GNU General Public License for more details. > + * > + * You should have received a copy of the GNU General Public License > + * along with this program. If not, see <https://www.gnu.org/licenses/>. > + */ > +#ifndef __SSIF_BMC_H__ > +#define __SSIF_BMC_H__ > + > +#define DEVICE_NAME "ipmi-ssif-host" > + > +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff) > + > +#define MSG_PAYLOAD_LEN_MAX 252 > + > +/* A standard SMBus Transaction is limited to 32 data bytes */ > +#define MAX_PAYLOAD_PER_TRANSACTION 32 > + > +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30 > +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31 > + > +#define SSIF_IPMI_SINGLEPART_WRITE 0x2 > +#define SSIF_IPMI_SINGLEPART_READ 0x3 > +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6 > +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7 > +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8 > +#define SSIF_IPMI_MULTIPART_READ_START 0x3 > +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9 > + > +struct ssif_msg { > + u8 len; > + u8 netfn_lun; > + u8 cmd; > + u8 payload[MSG_PAYLOAD_LEN_MAX]; > +} __packed; > + > +static inline u32 ssif_msg_len(struct ssif_msg *ssif_msg) > +{ > + return ssif_msg->len + 1; > +} > + > +#define SSIF_BMC_BUSY 0x01 > +#define SSIF_BMC_READY 0x02 > + > +struct ssif_bmc_ctx { > + struct i2c_client *client; > + struct miscdevice miscdev; > + u8 running; > + u8 smbus_cmd; > + struct ssif_msg request; > + bool request_available; > + struct ssif_msg response; > + bool response_in_progress; > + /* Response buffer for Multi-part Read Transaction */ > + u8 response_buf[MAX_PAYLOAD_PER_TRANSACTION]; > + /* Flag to identify a Multi-part Read Transaction */ > + bool is_singlepart_read; > + u8 nbytes_processed; > + u8 remain_len; > + u8 recv_len; > + /* Block Number of a Multi-part Read Transaction */ > + u8 block_num; > + size_t msg_idx; > + enum i2c_slave_event last_event; > + bool pec_support; > + /* spinlock */ > + spinlock_t lock; > + wait_queue_head_t wait_queue; > + void (*set_ssif_bmc_status)(struct ssif_bmc_ctx *ssif_bmc, unsigned int flags); > + void *priv; > +}; > + > +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file) > +{ > + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev); > +} > + > +struct ssif_bmc_ctx *ssif_bmc_alloc(struct i2c_client *client, int sizeof_priv); > + > +#endif /* __SSIF_BMC_H__ */ > -- > 2.28.0 >
On 19/05/2021 19:30, Corey Minyard wrote: > On Wed, May 19, 2021 at 02:49:29PM +0700, Quan Nguyen wrote: >> The SMBus system interface (SSIF) IPMI BMC driver can be used to perform >> in-band IPMI communication with their host in management (BMC) side. >> >> Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com> >> --- >> v3: >> + Removed redundant license info [Joel] >> + Switched to use traditional if-else [Joel] >> + Removed unused ssif_bmc_ioctl() [Joel] >> + Made handle_request()/complete_response() to return void [Joel] >> + Refactored send_ssif_bmc_response()/receive_ssif_bmc_request() [Corey] >> + Removed mutex [Corey] >> + Use spin_lock/unlock_irqsave/restore in callback [Corey] >> + Removed the unnecessary memset [Corey] >> + Switch to use dev_err() [Corey] >> >> v2: >> + Fixed compiling error with COMPILE_TEST for arc >> >> drivers/char/ipmi/Kconfig | 11 + >> drivers/char/ipmi/Makefile | 1 + >> drivers/char/ipmi/ssif_bmc.c | 605 +++++++++++++++++++++++++++++++++++ >> drivers/char/ipmi/ssif_bmc.h | 93 ++++++ >> 4 files changed, 710 insertions(+) >> create mode 100644 drivers/char/ipmi/ssif_bmc.c >> create mode 100644 drivers/char/ipmi/ssif_bmc.h >> >> diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig >> index 07847d9a459a..ad5c5161bcd6 100644 >> --- a/drivers/char/ipmi/Kconfig >> +++ b/drivers/char/ipmi/Kconfig >> @@ -133,6 +133,17 @@ config ASPEED_BT_IPMI_BMC >> found on Aspeed SOCs (AST2400 and AST2500). The driver >> implements the BMC side of the BT interface. >> >> +config SSIF_IPMI_BMC >> + tristate "SSIF IPMI BMC driver" >> + select I2C >> + select I2C_SLAVE >> + help >> + This enables the IPMI SMBus system interface (SSIF) at the >> + management (BMC) side. >> + >> + The driver implements the BMC side of the SMBus system >> + interface (SSIF). >> + >> config IPMB_DEVICE_INTERFACE >> tristate 'IPMB Interface handler' >> depends on I2C >> diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile >> index 0822adc2ec41..d04a214d74c4 100644 >> --- a/drivers/char/ipmi/Makefile >> +++ b/drivers/char/ipmi/Makefile >> @@ -27,3 +27,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o >> obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o >> obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o >> obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o >> +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o >> diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c >> new file mode 100644 >> index 000000000000..d0ea7059b1db >> --- /dev/null >> +++ b/drivers/char/ipmi/ssif_bmc.c >> @@ -0,0 +1,605 @@ >> +// SPDX-License-Identifier: GPL-2.0+ >> +/* >> + * The driver for BMC side of SSIF interface >> + * >> + * Copyright (c) 2021, Ampere Computing LLC >> + * >> + */ >> + >> +#include <linux/i2c.h> >> +#include <linux/miscdevice.h> >> +#include <linux/module.h> >> +#include <linux/of.h> >> +#include <linux/platform_device.h> >> +#include <linux/poll.h> >> +#include <linux/sched.h> >> +#include <linux/mutex.h> >> +#include <linux/spinlock.h> >> + >> +#include "ssif_bmc.h" >> + >> +/* Handle SSIF message that will be sent to user */ >> +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) >> +{ >> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); >> + struct ssif_msg msg; >> + unsigned long flags; >> + ssize_t ret; >> + >> + spin_lock_irqsave(&ssif_bmc->lock, flags); >> + while (!ssif_bmc->request_available) { >> + if (file->f_flags & O_NONBLOCK) { > > There is no real need to check this under the lock. It would simplify > the end of this function if you checked this outside the lock. > Thanks for your reviewing. Will apply change like below in next version: spin_lock_irqsave(&ssif_bmc->lock, flags); while (!ssif_bmc->request_available) { - if (file->f_flags & O_NONBLOCK) { - ret = -EAGAIN; - goto out_unlock; - } spin_unlock_irqrestore(&ssif_bmc->lock, flags); + if (file->f_flags & O_NONBLOCK) + return -EAGAIN; ret = wait_event_interruptible(ssif_bmc->wait_queue, ssif_bmc->request_available); if (ret) >> + ret = -EAGAIN; >> + goto out_unlock; >> + } >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + ret = wait_event_interruptible(ssif_bmc->wait_queue, >> + ssif_bmc->request_available); >> + if (ret) >> + return ret; >> + spin_lock_irqsave(&ssif_bmc->lock, flags); >> + } >> + >> + count = min_t(ssize_t, ssif_msg_len(&ssif_bmc->request), >> + min_t(ssize_t, sizeof(struct ssif_msg), count)); > > Just curious, what happens if userland supplies a buffer that is too > small? Is data lost? In that case, I would think returning an error > here would be the better thing, as opposed to silently truncating the > message. > Will return -EINVAL if buffer is too small in next version >> + memcpy(&msg, &ssif_bmc->request, count); >> + ssif_bmc->request_available = false; >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + >> + ret = copy_to_user(buf, &msg, count); >> + goto out; >> + >> +out_unlock: >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> +out: >> + return (ret < 0) ? ret : count; >> +} >> + >> +/* Handle SSIF message that is written by user */ >> +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count, >> + loff_t *ppos) >> +{ >> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); >> + struct ssif_msg msg; >> + unsigned long flags; >> + ssize_t ret; >> + >> + if (count > sizeof(struct ssif_msg)) >> + return -EINVAL; >> + >> + ret = copy_from_user(&msg, buf, count); >> + if (ret) >> + return ret; >> + >> + if (!msg.len || count < ssif_msg_len(&msg)) >> + return -EINVAL; >> + >> + spin_lock_irqsave(&ssif_bmc->lock, flags); >> + while (ssif_bmc->response_in_progress) { >> + if (file->f_flags & O_NONBLOCK) { > > Same comment as O_NONBLOCK before. > Will apply this follow the above in ssif_bmc_read() >> + ret = -EAGAIN; >> + goto out_unlock; >> + } >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + ret = wait_event_interruptible(ssif_bmc->wait_queue, >> + !ssif_bmc->response_in_progress); >> + if (ret) >> + goto out; >> + spin_lock_irqsave(&ssif_bmc->lock, flags); >> + } >> + >> + memcpy(&ssif_bmc->response, &msg, count); >> + ssif_bmc->is_singlepart_read = (ssif_msg_len(&msg) <= MAX_PAYLOAD_PER_TRANSACTION + 1); >> + ssif_bmc->response_in_progress = true; >> + if (ssif_bmc->set_ssif_bmc_status) >> + ssif_bmc->set_ssif_bmc_status(ssif_bmc, SSIF_BMC_READY); >> + >> +out_unlock: >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + >> +out: >> + return (ret < 0) ? ret : count; >> +} >> + >> +static int ssif_bmc_open(struct inode *inode, struct file *file) >> +{ >> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); >> + int ret = 0; >> + >> + spin_lock_irq(&ssif_bmc->lock); >> + if (!ssif_bmc->running) >> + ssif_bmc->running = 1; >> + else >> + ret = -EBUSY; >> + spin_unlock_irq(&ssif_bmc->lock); >> + >> + return ret; >> +} >> + >> +static unsigned int ssif_bmc_poll(struct file *file, poll_table *wait) >> +{ >> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); >> + unsigned int mask = 0; >> + >> + poll_wait(file, &ssif_bmc->wait_queue, wait); >> + >> + spin_lock_irq(&ssif_bmc->lock); >> + /* >> + * The request message is now available so userspace application can >> + * get the request >> + */ >> + if (ssif_bmc->request_available) >> + mask |= POLLIN; >> + >> + spin_unlock_irq(&ssif_bmc->lock); >> + >> + return mask; >> +} >> + >> +static int ssif_bmc_release(struct inode *inode, struct file *file) >> +{ >> + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); >> + >> + spin_lock_irq(&ssif_bmc->lock); >> + ssif_bmc->running = 0; >> + spin_unlock_irq(&ssif_bmc->lock); >> + >> + return 0; >> +} >> + >> +/* >> + * System calls to device interface for user apps >> + */ >> +static const struct file_operations ssif_bmc_fops = { >> + .owner = THIS_MODULE, >> + .open = ssif_bmc_open, >> + .read = ssif_bmc_read, >> + .write = ssif_bmc_write, >> + .release = ssif_bmc_release, >> + .poll = ssif_bmc_poll, >> +}; >> + >> +/* Called with ssif_bmc->lock held. */ >> +static void handle_request(struct ssif_bmc_ctx *ssif_bmc) >> +{ >> + if (ssif_bmc->set_ssif_bmc_status) >> + ssif_bmc->set_ssif_bmc_status(ssif_bmc, SSIF_BMC_BUSY); >> + >> + /* Request message is available to process */ >> + ssif_bmc->request_available = true; >> + /* >> + * This is the new READ request. >> + */ >> + wake_up_all(&ssif_bmc->wait_queue); >> +} >> + >> +/* Called with ssif_bmc->lock held. */ >> +static void complete_response(struct ssif_bmc_ctx *ssif_bmc) >> +{ >> + /* Invalidate response in buffer to denote it having been sent. */ >> + ssif_bmc->response.len = 0; >> + ssif_bmc->response_in_progress = false; >> + ssif_bmc->nbytes_processed = 0; >> + ssif_bmc->remain_len = 0; >> + wake_up_all(&ssif_bmc->wait_queue); >> +} >> + >> +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc, u8 *val) >> +{ >> + u8 response_len = 0; >> + int idx = 0; >> + u8 data_len; >> + >> + data_len = ssif_bmc->response.len; >> + switch (ssif_bmc->smbus_cmd) { >> + case SSIF_IPMI_MULTIPART_READ_START: >> + /* >> + * Read Start length is 32 bytes. >> + * Read Start transfer first 30 bytes of IPMI response >> + * and 2 special code 0x00, 0x01. >> + */ >> + *val = MAX_PAYLOAD_PER_TRANSACTION; >> + ssif_bmc->remain_len = data_len - MAX_IPMI_DATA_PER_START_TRANSACTION; >> + ssif_bmc->block_num = 0; >> + >> + ssif_bmc->response_buf[idx++] = 0x00; /* Start Flag */ >> + ssif_bmc->response_buf[idx++] = 0x01; /* Start Flag */ >> + ssif_bmc->response_buf[idx++] = ssif_bmc->response.netfn_lun; >> + ssif_bmc->response_buf[idx++] = ssif_bmc->response.cmd; >> + ssif_bmc->response_buf[idx++] = ssif_bmc->response.payload[0]; >> + >> + response_len = MAX_PAYLOAD_PER_TRANSACTION - idx; >> + >> + memcpy(&ssif_bmc->response_buf[idx], &ssif_bmc->response.payload[1], >> + response_len); >> + break; >> + >> + case SSIF_IPMI_MULTIPART_READ_MIDDLE: >> + /* >> + * IPMI READ Middle or READ End messages can carry up to 31 bytes >> + * IPMI data plus block number byte. >> + */ >> + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) { >> + /* >> + * This is READ End message >> + * Return length is the remaining response data length >> + * plus block number >> + * Block number 0xFF is to indicate this is last message >> + * >> + */ >> + *val = ssif_bmc->remain_len + 1; >> + ssif_bmc->block_num = 0xFF; >> + ssif_bmc->response_buf[idx++] = ssif_bmc->block_num; >> + response_len = ssif_bmc->remain_len; >> + /* Clean the buffer */ >> + memset(&ssif_bmc->response_buf[idx], 0, MAX_PAYLOAD_PER_TRANSACTION - idx); >> + } else { >> + /* >> + * This is READ Middle message >> + * Response length is the maximum SMBUS transfer length >> + * Block number byte is incremented >> + * Return length is maximum SMBUS transfer length >> + */ >> + *val = MAX_PAYLOAD_PER_TRANSACTION; >> + ssif_bmc->remain_len -= MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; >> + response_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; >> + ssif_bmc->response_buf[idx++] = ssif_bmc->block_num; >> + ssif_bmc->block_num++; >> + } >> + >> + memcpy(&ssif_bmc->response_buf[idx], >> + ssif_bmc->response.payload + 1 + ssif_bmc->nbytes_processed, >> + response_len); >> + break; >> + >> + default: >> + /* Do not expect to go to this case */ >> + dev_err(&ssif_bmc->client->dev, >> + "Error: Unexpected SMBus command received 0x%x\n", ssif_bmc->smbus_cmd); >> + break; >> + } >> + >> + ssif_bmc->nbytes_processed += response_len; >> +} >> + >> +/* Process the IPMI response that will be read by master */ >> +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val) >> +{ >> + u8 *buf; >> + u8 pec_len, addr, len; >> + u8 pec = 0; >> + >> + pec_len = ssif_bmc->pec_support ? 1 : 0; >> + /* PEC - Start Read Address */ >> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); >> + pec = i2c_smbus_pec(pec, &addr, 1); >> + /* PEC - SSIF Command */ >> + pec = i2c_smbus_pec(pec, &ssif_bmc->smbus_cmd, 1); >> + /* PEC - Restart Write Address */ >> + addr = addr | 0x01; >> + pec = i2c_smbus_pec(pec, &addr, 1); >> + >> + if (ssif_bmc->is_singlepart_read) { >> + /* Single-part Read processing */ >> + buf = (u8 *)&ssif_bmc->response; >> + >> + if (ssif_bmc->response.len && ssif_bmc->msg_idx < ssif_bmc->response.len) { >> + ssif_bmc->msg_idx++; >> + *val = buf[ssif_bmc->msg_idx]; >> + } else if (ssif_bmc->response.len && ssif_bmc->msg_idx == ssif_bmc->response.len) { >> + ssif_bmc->msg_idx++; >> + *val = i2c_smbus_pec(pec, buf, ssif_msg_len(&ssif_bmc->response)); >> + } else { >> + *val = 0; >> + } >> + /* Invalidate response buffer to denote it is sent */ >> + if (ssif_bmc->msg_idx + 1 >= (ssif_msg_len(&ssif_bmc->response) + pec_len)) >> + complete_response(ssif_bmc); >> + } else { >> + /* Multi-part Read processing */ >> + switch (ssif_bmc->smbus_cmd) { >> + case SSIF_IPMI_MULTIPART_READ_START: >> + case SSIF_IPMI_MULTIPART_READ_MIDDLE: >> + buf = (u8 *)&ssif_bmc->response_buf; >> + *val = buf[ssif_bmc->msg_idx]; >> + ssif_bmc->msg_idx++; >> + break; >> + default: >> + /* Do not expect to go to this case */ >> + dev_err(&ssif_bmc->client->dev, >> + "Error: Unexpected SMBus command received 0x%x\n", >> + ssif_bmc->smbus_cmd); >> + break; >> + } >> + len = (ssif_bmc->block_num == 0xFF) ? >> + ssif_bmc->remain_len + 1 : MAX_PAYLOAD_PER_TRANSACTION; >> + if (ssif_bmc->msg_idx == (len + 1)) { >> + pec = i2c_smbus_pec(pec, &len, 1); >> + *val = i2c_smbus_pec(pec, ssif_bmc->response_buf, len); >> + } >> + /* Invalidate response buffer to denote last response is sent */ >> + if (ssif_bmc->block_num == 0xFF && >> + ssif_bmc->msg_idx > (ssif_bmc->remain_len + pec_len)) { >> + complete_response(ssif_bmc); >> + } >> + } >> +} >> + >> +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val) >> +{ >> + u8 *buf; >> + u8 smbus_cmd; >> + >> + buf = (u8 *)&ssif_bmc->request; >> + if (ssif_bmc->msg_idx >= sizeof(struct ssif_msg)) > > Shouldn't you abort the message if you get too much data? Otherwise you > get silent truncation. > Will try to abort bad request in next version. >> + return; >> + >> + smbus_cmd = ssif_bmc->smbus_cmd; >> + switch (smbus_cmd) { >> + case SSIF_IPMI_SINGLEPART_WRITE: >> + /* Single-part write */ >> + buf[ssif_bmc->msg_idx - 1] = *val; >> + ssif_bmc->msg_idx++; >> + >> + break; > > Generally you put the space after the break, not before. You did this > right before, but didn't from here down in the file. > Will fix them in next version. >> + case SSIF_IPMI_MULTIPART_WRITE_START: >> + /* Reset length to zero */ >> + if (ssif_bmc->msg_idx == 1) >> + ssif_bmc->request.len = 0; > > What happens if you get this and you are in the middle of a message? > As per specs, this message should be discarded. This part is still missing. I'll try to add this feature in next version. >> + >> + fallthrough; >> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: >> + case SSIF_IPMI_MULTIPART_WRITE_END: > > What happens if you get these and you are not in a message? > Same as my comment above. >> + /* Multi-part write, 2nd byte received is length */ >> + if (ssif_bmc->msg_idx == 1) { >> + ssif_bmc->request.len += *val; >> + ssif_bmc->recv_len = *val; >> + } else { >> + buf[ssif_bmc->msg_idx - 1 + >> + ssif_bmc->request.len - ssif_bmc->recv_len] = *val; >> + } >> + >> + ssif_bmc->msg_idx++; >> + >> + break; >> + default: >> + /* Do not expect to go to this case */ >> + dev_err(&ssif_bmc->client->dev, >> + "Error: Unexpected SMBus command received 0x%x\n", ssif_bmc->smbus_cmd); >> + break; >> + } >> +} >> + >> +static bool validate_pec(struct ssif_bmc_ctx *ssif_bmc) >> +{ >> + u8 rpec = 0, cpec = 0; >> + bool ret = true; >> + u8 addr, index; >> + u8 *buf; >> + >> + buf = (u8 *)&ssif_bmc->request; >> + switch (ssif_bmc->smbus_cmd) { >> + case SSIF_IPMI_SINGLEPART_WRITE: >> + if ((ssif_bmc->msg_idx - 1) == ssif_msg_len(&ssif_bmc->request)) { >> + /* PEC is not included */ >> + ssif_bmc->pec_support = false; >> + return true; >> + } >> + >> + if ((ssif_bmc->msg_idx - 1) != (ssif_msg_len(&ssif_bmc->request) + 1)) >> + goto error; >> + >> + /* PEC is included */ >> + ssif_bmc->pec_support = true; >> + rpec = buf[ssif_bmc->msg_idx - 2]; >> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); >> + cpec = i2c_smbus_pec(cpec, &addr, 1); >> + cpec = i2c_smbus_pec(cpec, &ssif_bmc->smbus_cmd, 1); >> + cpec = i2c_smbus_pec(cpec, buf, ssif_msg_len(&ssif_bmc->request)); >> + if (rpec != cpec) { >> + dev_err(&ssif_bmc->client->dev, "Bad PEC 0x%02x vs. 0x%02x\n", rpec, cpec); >> + ret = false; >> + } >> + >> + break; >> + case SSIF_IPMI_MULTIPART_WRITE_START: >> + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: >> + case SSIF_IPMI_MULTIPART_WRITE_END: >> + index = ssif_bmc->request.len - ssif_bmc->recv_len; >> + if ((ssif_bmc->msg_idx - 1 + index) == ssif_msg_len(&ssif_bmc->request)) { >> + /* PEC is not included */ >> + ssif_bmc->pec_support = false; >> + return true; >> + } >> + >> + if ((ssif_bmc->msg_idx - 1 + index) != (ssif_msg_len(&ssif_bmc->request) + 1)) >> + goto error; >> + >> + /* PEC is included */ >> + ssif_bmc->pec_support = true; >> + rpec = buf[ssif_bmc->msg_idx - 2 + index]; >> + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); >> + cpec = i2c_smbus_pec(cpec, &addr, 1); >> + cpec = i2c_smbus_pec(cpec, &ssif_bmc->smbus_cmd, 1); >> + cpec = i2c_smbus_pec(cpec, &ssif_bmc->recv_len, 1); >> + /* As SMBus specification does not allow the length >> + * (byte count) in the Write-Block protocol to be zero. >> + * Therefore, it is illegal to have the last Middle >> + * transaction in the sequence carry 32-bytes and have >> + * a length of ‘0’ in the End transaction. >> + * But some users may try to use this way and we should >> + * prevent ssif_bmc driver broken in this case. >> + */ >> + if (ssif_bmc->recv_len != 0) >> + cpec = i2c_smbus_pec(cpec, buf + 1 + index, ssif_bmc->recv_len); >> + >> + if (rpec != cpec) { >> + dev_err(&ssif_bmc->client->dev, "Bad PEC 0x%02x vs. 0x%02x\n", rpec, cpec); >> + ret = false; >> + } >> + >> + break; >> + default: >> + break; >> + } >> + >> + return ret; >> +error: >> + /* Do not expect to go to this case */ >> + dev_err(&ssif_bmc->client->dev, >> + "Error: Unexpected length received %d\n", ssif_msg_len(&ssif_bmc->request)); >> + >> + return false; >> +} >> + >> +static void complete_write_received(struct ssif_bmc_ctx *ssif_bmc) >> +{ >> + u8 cmd = ssif_bmc->smbus_cmd; >> + >> + /* A BMC that receives an invalid PEC shall drop the data for the write >> + * transaction and any further transactions (read or write) until >> + * the next valid read or write Start transaction is received >> + */ >> + if (!validate_pec(ssif_bmc)) { >> + dev_err(&ssif_bmc->client->dev, "Received invalid PEC\n"); >> + return; >> + } >> + >> + if (cmd == SSIF_IPMI_SINGLEPART_WRITE || cmd == SSIF_IPMI_MULTIPART_WRITE_END) >> + handle_request(ssif_bmc); >> +} >> + >> +static void initialize_transfer(struct ssif_bmc_ctx *ssif_bmc, u8 *val) >> +{ >> + /* SMBUS command can vary (single or multi-part) */ >> + ssif_bmc->smbus_cmd = *val; >> + ssif_bmc->msg_idx++; >> + >> + if (ssif_bmc->smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE || >> + ssif_bmc->smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_START) { >> + /* >> + * The response can be delayed in BMC causing host SSIF driver >> + * to timeout and send a new request once BMC slave is ready. >> + * In that case check for pending response and clear it >> + */ >> + if (ssif_bmc->response_in_progress) { >> + dev_err(&ssif_bmc->client->dev, >> + "Warn: SSIF new request with pending response"); >> + complete_response(ssif_bmc); >> + } >> + } else if (unlikely(ssif_bmc->smbus_cmd != SSIF_IPMI_SINGLEPART_READ && >> + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_WRITE_MIDDLE && >> + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_WRITE_END && >> + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_READ_START && >> + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_READ_MIDDLE)) { >> + /* Unknown command, clear it */ >> + dev_err(&ssif_bmc->client->dev, "Warn: Unknown SMBus command"); >> + complete_response(ssif_bmc); >> + } >> +} >> + >> +/* >> + * Callback function to handle I2C slave events >> + */ >> +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val) >> +{ >> + unsigned long flags; >> + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client); >> + >> + spin_lock_irqsave(&ssif_bmc->lock, flags); >> + >> + /* I2C Event Handler: >> + * I2C_SLAVE_READ_REQUESTED 0x0 >> + * I2C_SLAVE_WRITE_REQUESTED 0x1 >> + * I2C_SLAVE_READ_PROCESSED 0x2 >> + * I2C_SLAVE_WRITE_RECEIVED 0x3 >> + * I2C_SLAVE_STOP 0x4 >> + */ >> + switch (event) { >> + case I2C_SLAVE_READ_REQUESTED: >> + ssif_bmc->msg_idx = 0; >> + if (ssif_bmc->is_singlepart_read) >> + *val = ssif_bmc->response.len; >> + else >> + set_multipart_response_buffer(ssif_bmc, val); >> + break; >> + >> + case I2C_SLAVE_WRITE_REQUESTED: >> + ssif_bmc->msg_idx = 0; >> + break; >> + >> + case I2C_SLAVE_READ_PROCESSED: >> + handle_read_processed(ssif_bmc, val); >> + break; >> + >> + case I2C_SLAVE_WRITE_RECEIVED: >> + if (ssif_bmc->msg_idx) >> + handle_write_received(ssif_bmc, val); >> + else >> + initialize_transfer(ssif_bmc, val); >> + >> + break; >> + >> + case I2C_SLAVE_STOP: >> + if (ssif_bmc->last_event == I2C_SLAVE_WRITE_RECEIVED) >> + complete_write_received(ssif_bmc); >> + /* Reset message index */ >> + ssif_bmc->msg_idx = 0; >> + break; >> + >> + default: >> + break; >> + } >> + ssif_bmc->last_event = event; >> + spin_unlock_irqrestore(&ssif_bmc->lock, flags); >> + >> + return 0; >> +} >> + >> +struct ssif_bmc_ctx *ssif_bmc_alloc(struct i2c_client *client, int sizeof_priv) >> +{ >> + struct ssif_bmc_ctx *ssif_bmc; >> + int ret; >> + >> + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc) + sizeof_priv, GFP_KERNEL); >> + if (!ssif_bmc) >> + return ERR_PTR(-ENOMEM); >> + >> + spin_lock_init(&ssif_bmc->lock); >> + >> + init_waitqueue_head(&ssif_bmc->wait_queue); >> + ssif_bmc->request_available = false; >> + ssif_bmc->response_in_progress = false; >> + >> + /* Register misc device interface */ >> + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR; >> + ssif_bmc->miscdev.name = DEVICE_NAME; >> + ssif_bmc->miscdev.fops = &ssif_bmc_fops; >> + ssif_bmc->miscdev.parent = &client->dev; >> + ret = misc_register(&ssif_bmc->miscdev); >> + if (ret) >> + goto out; >> + >> + ssif_bmc->client = client; >> + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE; >> + >> + /* Register I2C slave */ >> + i2c_set_clientdata(client, ssif_bmc); >> + ret = i2c_slave_register(client, ssif_bmc_cb); >> + if (ret) { >> + misc_deregister(&ssif_bmc->miscdev); >> + goto out; >> + } >> + >> + return ssif_bmc; >> + >> +out: >> + devm_kfree(&client->dev, ssif_bmc); >> + return ERR_PTR(ret); >> +} >> +EXPORT_SYMBOL(ssif_bmc_alloc); >> + >> +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>"); >> +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>"); >> +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface."); >> +MODULE_LICENSE("GPL v2"); >> diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h >> new file mode 100644 >> index 000000000000..eab540061f14 >> --- /dev/null >> +++ b/drivers/char/ipmi/ssif_bmc.h >> @@ -0,0 +1,93 @@ >> +/* SPDX-License-Identifier: GPL-2.0+ */ >> +/* >> + * The driver for BMC side of SSIF interface >> + * >> + * Copyright (c) 2021, Ampere Computing LLC >> + * >> + * This program is free software; you can redistribute it and/or >> + * modify it under the terms of the GNU General Public License as >> + * published by the Free Software Foundation; either version 2 of >> + * the License, or (at your option) any later version. >> + * >> + * This program is distributed in the hope that it will be useful, >> + * but WITHOUT ANY WARRANTY; without even the implied warranty of >> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the >> + * GNU General Public License for more details. >> + * >> + * You should have received a copy of the GNU General Public License >> + * along with this program. If not, see <https://www.gnu.org/licenses/>. >> + */ >> +#ifndef __SSIF_BMC_H__ >> +#define __SSIF_BMC_H__ >> + >> +#define DEVICE_NAME "ipmi-ssif-host" >> + >> +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff) >> + >> +#define MSG_PAYLOAD_LEN_MAX 252 >> + >> +/* A standard SMBus Transaction is limited to 32 data bytes */ >> +#define MAX_PAYLOAD_PER_TRANSACTION 32 >> + >> +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30 >> +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31 >> + >> +#define SSIF_IPMI_SINGLEPART_WRITE 0x2 >> +#define SSIF_IPMI_SINGLEPART_READ 0x3 >> +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6 >> +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7 >> +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8 >> +#define SSIF_IPMI_MULTIPART_READ_START 0x3 >> +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9 >> + >> +struct ssif_msg { >> + u8 len; >> + u8 netfn_lun; >> + u8 cmd; >> + u8 payload[MSG_PAYLOAD_LEN_MAX]; >> +} __packed; >> + >> +static inline u32 ssif_msg_len(struct ssif_msg *ssif_msg) >> +{ >> + return ssif_msg->len + 1; >> +} >> + >> +#define SSIF_BMC_BUSY 0x01 >> +#define SSIF_BMC_READY 0x02 >> + >> +struct ssif_bmc_ctx { >> + struct i2c_client *client; >> + struct miscdevice miscdev; >> + u8 running; >> + u8 smbus_cmd; >> + struct ssif_msg request; >> + bool request_available; >> + struct ssif_msg response; >> + bool response_in_progress; >> + /* Response buffer for Multi-part Read Transaction */ >> + u8 response_buf[MAX_PAYLOAD_PER_TRANSACTION]; >> + /* Flag to identify a Multi-part Read Transaction */ >> + bool is_singlepart_read; >> + u8 nbytes_processed; >> + u8 remain_len; >> + u8 recv_len; >> + /* Block Number of a Multi-part Read Transaction */ >> + u8 block_num; >> + size_t msg_idx; >> + enum i2c_slave_event last_event; >> + bool pec_support; >> + /* spinlock */ >> + spinlock_t lock; >> + wait_queue_head_t wait_queue; >> + void (*set_ssif_bmc_status)(struct ssif_bmc_ctx *ssif_bmc, unsigned int flags); >> + void *priv; >> +}; >> + >> +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file) >> +{ >> + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev); >> +} >> + >> +struct ssif_bmc_ctx *ssif_bmc_alloc(struct i2c_client *client, int sizeof_priv); >> + >> +#endif /* __SSIF_BMC_H__ */ >> -- >> 2.28.0 >>
diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig index 07847d9a459a..ad5c5161bcd6 100644 --- a/drivers/char/ipmi/Kconfig +++ b/drivers/char/ipmi/Kconfig @@ -133,6 +133,17 @@ config ASPEED_BT_IPMI_BMC found on Aspeed SOCs (AST2400 and AST2500). The driver implements the BMC side of the BT interface. +config SSIF_IPMI_BMC + tristate "SSIF IPMI BMC driver" + select I2C + select I2C_SLAVE + help + This enables the IPMI SMBus system interface (SSIF) at the + management (BMC) side. + + The driver implements the BMC side of the SMBus system + interface (SSIF). + config IPMB_DEVICE_INTERFACE tristate 'IPMB Interface handler' depends on I2C diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile index 0822adc2ec41..d04a214d74c4 100644 --- a/drivers/char/ipmi/Makefile +++ b/drivers/char/ipmi/Makefile @@ -27,3 +27,4 @@ obj-$(CONFIG_ASPEED_BT_IPMI_BMC) += bt-bmc.o obj-$(CONFIG_ASPEED_KCS_IPMI_BMC) += kcs_bmc_aspeed.o obj-$(CONFIG_NPCM7XX_KCS_IPMI_BMC) += kcs_bmc_npcm7xx.o obj-$(CONFIG_IPMB_DEVICE_INTERFACE) += ipmb_dev_int.o +obj-$(CONFIG_SSIF_IPMI_BMC) += ssif_bmc.o diff --git a/drivers/char/ipmi/ssif_bmc.c b/drivers/char/ipmi/ssif_bmc.c new file mode 100644 index 000000000000..d0ea7059b1db --- /dev/null +++ b/drivers/char/ipmi/ssif_bmc.c @@ -0,0 +1,605 @@ +// SPDX-License-Identifier: GPL-2.0+ +/* + * The driver for BMC side of SSIF interface + * + * Copyright (c) 2021, Ampere Computing LLC + * + */ + +#include <linux/i2c.h> +#include <linux/miscdevice.h> +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/poll.h> +#include <linux/sched.h> +#include <linux/mutex.h> +#include <linux/spinlock.h> + +#include "ssif_bmc.h" + +/* Handle SSIF message that will be sent to user */ +static ssize_t ssif_bmc_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) +{ + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); + struct ssif_msg msg; + unsigned long flags; + ssize_t ret; + + spin_lock_irqsave(&ssif_bmc->lock, flags); + while (!ssif_bmc->request_available) { + if (file->f_flags & O_NONBLOCK) { + ret = -EAGAIN; + goto out_unlock; + } + spin_unlock_irqrestore(&ssif_bmc->lock, flags); + ret = wait_event_interruptible(ssif_bmc->wait_queue, + ssif_bmc->request_available); + if (ret) + return ret; + spin_lock_irqsave(&ssif_bmc->lock, flags); + } + + count = min_t(ssize_t, ssif_msg_len(&ssif_bmc->request), + min_t(ssize_t, sizeof(struct ssif_msg), count)); + memcpy(&msg, &ssif_bmc->request, count); + ssif_bmc->request_available = false; + spin_unlock_irqrestore(&ssif_bmc->lock, flags); + + ret = copy_to_user(buf, &msg, count); + goto out; + +out_unlock: + spin_unlock_irqrestore(&ssif_bmc->lock, flags); +out: + return (ret < 0) ? ret : count; +} + +/* Handle SSIF message that is written by user */ +static ssize_t ssif_bmc_write(struct file *file, const char __user *buf, size_t count, + loff_t *ppos) +{ + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); + struct ssif_msg msg; + unsigned long flags; + ssize_t ret; + + if (count > sizeof(struct ssif_msg)) + return -EINVAL; + + ret = copy_from_user(&msg, buf, count); + if (ret) + return ret; + + if (!msg.len || count < ssif_msg_len(&msg)) + return -EINVAL; + + spin_lock_irqsave(&ssif_bmc->lock, flags); + while (ssif_bmc->response_in_progress) { + if (file->f_flags & O_NONBLOCK) { + ret = -EAGAIN; + goto out_unlock; + } + spin_unlock_irqrestore(&ssif_bmc->lock, flags); + ret = wait_event_interruptible(ssif_bmc->wait_queue, + !ssif_bmc->response_in_progress); + if (ret) + goto out; + spin_lock_irqsave(&ssif_bmc->lock, flags); + } + + memcpy(&ssif_bmc->response, &msg, count); + ssif_bmc->is_singlepart_read = (ssif_msg_len(&msg) <= MAX_PAYLOAD_PER_TRANSACTION + 1); + ssif_bmc->response_in_progress = true; + if (ssif_bmc->set_ssif_bmc_status) + ssif_bmc->set_ssif_bmc_status(ssif_bmc, SSIF_BMC_READY); + +out_unlock: + spin_unlock_irqrestore(&ssif_bmc->lock, flags); + +out: + return (ret < 0) ? ret : count; +} + +static int ssif_bmc_open(struct inode *inode, struct file *file) +{ + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); + int ret = 0; + + spin_lock_irq(&ssif_bmc->lock); + if (!ssif_bmc->running) + ssif_bmc->running = 1; + else + ret = -EBUSY; + spin_unlock_irq(&ssif_bmc->lock); + + return ret; +} + +static unsigned int ssif_bmc_poll(struct file *file, poll_table *wait) +{ + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); + unsigned int mask = 0; + + poll_wait(file, &ssif_bmc->wait_queue, wait); + + spin_lock_irq(&ssif_bmc->lock); + /* + * The request message is now available so userspace application can + * get the request + */ + if (ssif_bmc->request_available) + mask |= POLLIN; + + spin_unlock_irq(&ssif_bmc->lock); + + return mask; +} + +static int ssif_bmc_release(struct inode *inode, struct file *file) +{ + struct ssif_bmc_ctx *ssif_bmc = to_ssif_bmc(file); + + spin_lock_irq(&ssif_bmc->lock); + ssif_bmc->running = 0; + spin_unlock_irq(&ssif_bmc->lock); + + return 0; +} + +/* + * System calls to device interface for user apps + */ +static const struct file_operations ssif_bmc_fops = { + .owner = THIS_MODULE, + .open = ssif_bmc_open, + .read = ssif_bmc_read, + .write = ssif_bmc_write, + .release = ssif_bmc_release, + .poll = ssif_bmc_poll, +}; + +/* Called with ssif_bmc->lock held. */ +static void handle_request(struct ssif_bmc_ctx *ssif_bmc) +{ + if (ssif_bmc->set_ssif_bmc_status) + ssif_bmc->set_ssif_bmc_status(ssif_bmc, SSIF_BMC_BUSY); + + /* Request message is available to process */ + ssif_bmc->request_available = true; + /* + * This is the new READ request. + */ + wake_up_all(&ssif_bmc->wait_queue); +} + +/* Called with ssif_bmc->lock held. */ +static void complete_response(struct ssif_bmc_ctx *ssif_bmc) +{ + /* Invalidate response in buffer to denote it having been sent. */ + ssif_bmc->response.len = 0; + ssif_bmc->response_in_progress = false; + ssif_bmc->nbytes_processed = 0; + ssif_bmc->remain_len = 0; + wake_up_all(&ssif_bmc->wait_queue); +} + +static void set_multipart_response_buffer(struct ssif_bmc_ctx *ssif_bmc, u8 *val) +{ + u8 response_len = 0; + int idx = 0; + u8 data_len; + + data_len = ssif_bmc->response.len; + switch (ssif_bmc->smbus_cmd) { + case SSIF_IPMI_MULTIPART_READ_START: + /* + * Read Start length is 32 bytes. + * Read Start transfer first 30 bytes of IPMI response + * and 2 special code 0x00, 0x01. + */ + *val = MAX_PAYLOAD_PER_TRANSACTION; + ssif_bmc->remain_len = data_len - MAX_IPMI_DATA_PER_START_TRANSACTION; + ssif_bmc->block_num = 0; + + ssif_bmc->response_buf[idx++] = 0x00; /* Start Flag */ + ssif_bmc->response_buf[idx++] = 0x01; /* Start Flag */ + ssif_bmc->response_buf[idx++] = ssif_bmc->response.netfn_lun; + ssif_bmc->response_buf[idx++] = ssif_bmc->response.cmd; + ssif_bmc->response_buf[idx++] = ssif_bmc->response.payload[0]; + + response_len = MAX_PAYLOAD_PER_TRANSACTION - idx; + + memcpy(&ssif_bmc->response_buf[idx], &ssif_bmc->response.payload[1], + response_len); + break; + + case SSIF_IPMI_MULTIPART_READ_MIDDLE: + /* + * IPMI READ Middle or READ End messages can carry up to 31 bytes + * IPMI data plus block number byte. + */ + if (ssif_bmc->remain_len < MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION) { + /* + * This is READ End message + * Return length is the remaining response data length + * plus block number + * Block number 0xFF is to indicate this is last message + * + */ + *val = ssif_bmc->remain_len + 1; + ssif_bmc->block_num = 0xFF; + ssif_bmc->response_buf[idx++] = ssif_bmc->block_num; + response_len = ssif_bmc->remain_len; + /* Clean the buffer */ + memset(&ssif_bmc->response_buf[idx], 0, MAX_PAYLOAD_PER_TRANSACTION - idx); + } else { + /* + * This is READ Middle message + * Response length is the maximum SMBUS transfer length + * Block number byte is incremented + * Return length is maximum SMBUS transfer length + */ + *val = MAX_PAYLOAD_PER_TRANSACTION; + ssif_bmc->remain_len -= MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; + response_len = MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION; + ssif_bmc->response_buf[idx++] = ssif_bmc->block_num; + ssif_bmc->block_num++; + } + + memcpy(&ssif_bmc->response_buf[idx], + ssif_bmc->response.payload + 1 + ssif_bmc->nbytes_processed, + response_len); + break; + + default: + /* Do not expect to go to this case */ + dev_err(&ssif_bmc->client->dev, + "Error: Unexpected SMBus command received 0x%x\n", ssif_bmc->smbus_cmd); + break; + } + + ssif_bmc->nbytes_processed += response_len; +} + +/* Process the IPMI response that will be read by master */ +static void handle_read_processed(struct ssif_bmc_ctx *ssif_bmc, u8 *val) +{ + u8 *buf; + u8 pec_len, addr, len; + u8 pec = 0; + + pec_len = ssif_bmc->pec_support ? 1 : 0; + /* PEC - Start Read Address */ + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); + pec = i2c_smbus_pec(pec, &addr, 1); + /* PEC - SSIF Command */ + pec = i2c_smbus_pec(pec, &ssif_bmc->smbus_cmd, 1); + /* PEC - Restart Write Address */ + addr = addr | 0x01; + pec = i2c_smbus_pec(pec, &addr, 1); + + if (ssif_bmc->is_singlepart_read) { + /* Single-part Read processing */ + buf = (u8 *)&ssif_bmc->response; + + if (ssif_bmc->response.len && ssif_bmc->msg_idx < ssif_bmc->response.len) { + ssif_bmc->msg_idx++; + *val = buf[ssif_bmc->msg_idx]; + } else if (ssif_bmc->response.len && ssif_bmc->msg_idx == ssif_bmc->response.len) { + ssif_bmc->msg_idx++; + *val = i2c_smbus_pec(pec, buf, ssif_msg_len(&ssif_bmc->response)); + } else { + *val = 0; + } + /* Invalidate response buffer to denote it is sent */ + if (ssif_bmc->msg_idx + 1 >= (ssif_msg_len(&ssif_bmc->response) + pec_len)) + complete_response(ssif_bmc); + } else { + /* Multi-part Read processing */ + switch (ssif_bmc->smbus_cmd) { + case SSIF_IPMI_MULTIPART_READ_START: + case SSIF_IPMI_MULTIPART_READ_MIDDLE: + buf = (u8 *)&ssif_bmc->response_buf; + *val = buf[ssif_bmc->msg_idx]; + ssif_bmc->msg_idx++; + break; + default: + /* Do not expect to go to this case */ + dev_err(&ssif_bmc->client->dev, + "Error: Unexpected SMBus command received 0x%x\n", + ssif_bmc->smbus_cmd); + break; + } + len = (ssif_bmc->block_num == 0xFF) ? + ssif_bmc->remain_len + 1 : MAX_PAYLOAD_PER_TRANSACTION; + if (ssif_bmc->msg_idx == (len + 1)) { + pec = i2c_smbus_pec(pec, &len, 1); + *val = i2c_smbus_pec(pec, ssif_bmc->response_buf, len); + } + /* Invalidate response buffer to denote last response is sent */ + if (ssif_bmc->block_num == 0xFF && + ssif_bmc->msg_idx > (ssif_bmc->remain_len + pec_len)) { + complete_response(ssif_bmc); + } + } +} + +static void handle_write_received(struct ssif_bmc_ctx *ssif_bmc, u8 *val) +{ + u8 *buf; + u8 smbus_cmd; + + buf = (u8 *)&ssif_bmc->request; + if (ssif_bmc->msg_idx >= sizeof(struct ssif_msg)) + return; + + smbus_cmd = ssif_bmc->smbus_cmd; + switch (smbus_cmd) { + case SSIF_IPMI_SINGLEPART_WRITE: + /* Single-part write */ + buf[ssif_bmc->msg_idx - 1] = *val; + ssif_bmc->msg_idx++; + + break; + case SSIF_IPMI_MULTIPART_WRITE_START: + /* Reset length to zero */ + if (ssif_bmc->msg_idx == 1) + ssif_bmc->request.len = 0; + + fallthrough; + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: + case SSIF_IPMI_MULTIPART_WRITE_END: + /* Multi-part write, 2nd byte received is length */ + if (ssif_bmc->msg_idx == 1) { + ssif_bmc->request.len += *val; + ssif_bmc->recv_len = *val; + } else { + buf[ssif_bmc->msg_idx - 1 + + ssif_bmc->request.len - ssif_bmc->recv_len] = *val; + } + + ssif_bmc->msg_idx++; + + break; + default: + /* Do not expect to go to this case */ + dev_err(&ssif_bmc->client->dev, + "Error: Unexpected SMBus command received 0x%x\n", ssif_bmc->smbus_cmd); + break; + } +} + +static bool validate_pec(struct ssif_bmc_ctx *ssif_bmc) +{ + u8 rpec = 0, cpec = 0; + bool ret = true; + u8 addr, index; + u8 *buf; + + buf = (u8 *)&ssif_bmc->request; + switch (ssif_bmc->smbus_cmd) { + case SSIF_IPMI_SINGLEPART_WRITE: + if ((ssif_bmc->msg_idx - 1) == ssif_msg_len(&ssif_bmc->request)) { + /* PEC is not included */ + ssif_bmc->pec_support = false; + return true; + } + + if ((ssif_bmc->msg_idx - 1) != (ssif_msg_len(&ssif_bmc->request) + 1)) + goto error; + + /* PEC is included */ + ssif_bmc->pec_support = true; + rpec = buf[ssif_bmc->msg_idx - 2]; + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); + cpec = i2c_smbus_pec(cpec, &addr, 1); + cpec = i2c_smbus_pec(cpec, &ssif_bmc->smbus_cmd, 1); + cpec = i2c_smbus_pec(cpec, buf, ssif_msg_len(&ssif_bmc->request)); + if (rpec != cpec) { + dev_err(&ssif_bmc->client->dev, "Bad PEC 0x%02x vs. 0x%02x\n", rpec, cpec); + ret = false; + } + + break; + case SSIF_IPMI_MULTIPART_WRITE_START: + case SSIF_IPMI_MULTIPART_WRITE_MIDDLE: + case SSIF_IPMI_MULTIPART_WRITE_END: + index = ssif_bmc->request.len - ssif_bmc->recv_len; + if ((ssif_bmc->msg_idx - 1 + index) == ssif_msg_len(&ssif_bmc->request)) { + /* PEC is not included */ + ssif_bmc->pec_support = false; + return true; + } + + if ((ssif_bmc->msg_idx - 1 + index) != (ssif_msg_len(&ssif_bmc->request) + 1)) + goto error; + + /* PEC is included */ + ssif_bmc->pec_support = true; + rpec = buf[ssif_bmc->msg_idx - 2 + index]; + addr = GET_8BIT_ADDR(ssif_bmc->client->addr); + cpec = i2c_smbus_pec(cpec, &addr, 1); + cpec = i2c_smbus_pec(cpec, &ssif_bmc->smbus_cmd, 1); + cpec = i2c_smbus_pec(cpec, &ssif_bmc->recv_len, 1); + /* As SMBus specification does not allow the length + * (byte count) in the Write-Block protocol to be zero. + * Therefore, it is illegal to have the last Middle + * transaction in the sequence carry 32-bytes and have + * a length of ‘0’ in the End transaction. + * But some users may try to use this way and we should + * prevent ssif_bmc driver broken in this case. + */ + if (ssif_bmc->recv_len != 0) + cpec = i2c_smbus_pec(cpec, buf + 1 + index, ssif_bmc->recv_len); + + if (rpec != cpec) { + dev_err(&ssif_bmc->client->dev, "Bad PEC 0x%02x vs. 0x%02x\n", rpec, cpec); + ret = false; + } + + break; + default: + break; + } + + return ret; +error: + /* Do not expect to go to this case */ + dev_err(&ssif_bmc->client->dev, + "Error: Unexpected length received %d\n", ssif_msg_len(&ssif_bmc->request)); + + return false; +} + +static void complete_write_received(struct ssif_bmc_ctx *ssif_bmc) +{ + u8 cmd = ssif_bmc->smbus_cmd; + + /* A BMC that receives an invalid PEC shall drop the data for the write + * transaction and any further transactions (read or write) until + * the next valid read or write Start transaction is received + */ + if (!validate_pec(ssif_bmc)) { + dev_err(&ssif_bmc->client->dev, "Received invalid PEC\n"); + return; + } + + if (cmd == SSIF_IPMI_SINGLEPART_WRITE || cmd == SSIF_IPMI_MULTIPART_WRITE_END) + handle_request(ssif_bmc); +} + +static void initialize_transfer(struct ssif_bmc_ctx *ssif_bmc, u8 *val) +{ + /* SMBUS command can vary (single or multi-part) */ + ssif_bmc->smbus_cmd = *val; + ssif_bmc->msg_idx++; + + if (ssif_bmc->smbus_cmd == SSIF_IPMI_SINGLEPART_WRITE || + ssif_bmc->smbus_cmd == SSIF_IPMI_MULTIPART_WRITE_START) { + /* + * The response can be delayed in BMC causing host SSIF driver + * to timeout and send a new request once BMC slave is ready. + * In that case check for pending response and clear it + */ + if (ssif_bmc->response_in_progress) { + dev_err(&ssif_bmc->client->dev, + "Warn: SSIF new request with pending response"); + complete_response(ssif_bmc); + } + } else if (unlikely(ssif_bmc->smbus_cmd != SSIF_IPMI_SINGLEPART_READ && + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_WRITE_MIDDLE && + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_WRITE_END && + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_READ_START && + ssif_bmc->smbus_cmd != SSIF_IPMI_MULTIPART_READ_MIDDLE)) { + /* Unknown command, clear it */ + dev_err(&ssif_bmc->client->dev, "Warn: Unknown SMBus command"); + complete_response(ssif_bmc); + } +} + +/* + * Callback function to handle I2C slave events + */ +static int ssif_bmc_cb(struct i2c_client *client, enum i2c_slave_event event, u8 *val) +{ + unsigned long flags; + struct ssif_bmc_ctx *ssif_bmc = i2c_get_clientdata(client); + + spin_lock_irqsave(&ssif_bmc->lock, flags); + + /* I2C Event Handler: + * I2C_SLAVE_READ_REQUESTED 0x0 + * I2C_SLAVE_WRITE_REQUESTED 0x1 + * I2C_SLAVE_READ_PROCESSED 0x2 + * I2C_SLAVE_WRITE_RECEIVED 0x3 + * I2C_SLAVE_STOP 0x4 + */ + switch (event) { + case I2C_SLAVE_READ_REQUESTED: + ssif_bmc->msg_idx = 0; + if (ssif_bmc->is_singlepart_read) + *val = ssif_bmc->response.len; + else + set_multipart_response_buffer(ssif_bmc, val); + break; + + case I2C_SLAVE_WRITE_REQUESTED: + ssif_bmc->msg_idx = 0; + break; + + case I2C_SLAVE_READ_PROCESSED: + handle_read_processed(ssif_bmc, val); + break; + + case I2C_SLAVE_WRITE_RECEIVED: + if (ssif_bmc->msg_idx) + handle_write_received(ssif_bmc, val); + else + initialize_transfer(ssif_bmc, val); + + break; + + case I2C_SLAVE_STOP: + if (ssif_bmc->last_event == I2C_SLAVE_WRITE_RECEIVED) + complete_write_received(ssif_bmc); + /* Reset message index */ + ssif_bmc->msg_idx = 0; + break; + + default: + break; + } + ssif_bmc->last_event = event; + spin_unlock_irqrestore(&ssif_bmc->lock, flags); + + return 0; +} + +struct ssif_bmc_ctx *ssif_bmc_alloc(struct i2c_client *client, int sizeof_priv) +{ + struct ssif_bmc_ctx *ssif_bmc; + int ret; + + ssif_bmc = devm_kzalloc(&client->dev, sizeof(*ssif_bmc) + sizeof_priv, GFP_KERNEL); + if (!ssif_bmc) + return ERR_PTR(-ENOMEM); + + spin_lock_init(&ssif_bmc->lock); + + init_waitqueue_head(&ssif_bmc->wait_queue); + ssif_bmc->request_available = false; + ssif_bmc->response_in_progress = false; + + /* Register misc device interface */ + ssif_bmc->miscdev.minor = MISC_DYNAMIC_MINOR; + ssif_bmc->miscdev.name = DEVICE_NAME; + ssif_bmc->miscdev.fops = &ssif_bmc_fops; + ssif_bmc->miscdev.parent = &client->dev; + ret = misc_register(&ssif_bmc->miscdev); + if (ret) + goto out; + + ssif_bmc->client = client; + ssif_bmc->client->flags |= I2C_CLIENT_SLAVE; + + /* Register I2C slave */ + i2c_set_clientdata(client, ssif_bmc); + ret = i2c_slave_register(client, ssif_bmc_cb); + if (ret) { + misc_deregister(&ssif_bmc->miscdev); + goto out; + } + + return ssif_bmc; + +out: + devm_kfree(&client->dev, ssif_bmc); + return ERR_PTR(ret); +} +EXPORT_SYMBOL(ssif_bmc_alloc); + +MODULE_AUTHOR("Chuong Tran <chuong@os.amperecomputing.com>"); +MODULE_AUTHOR("Quan Nguyen <quan@os.amperecomputing.com>"); +MODULE_DESCRIPTION("Linux device driver of the BMC IPMI SSIF interface."); +MODULE_LICENSE("GPL v2"); diff --git a/drivers/char/ipmi/ssif_bmc.h b/drivers/char/ipmi/ssif_bmc.h new file mode 100644 index 000000000000..eab540061f14 --- /dev/null +++ b/drivers/char/ipmi/ssif_bmc.h @@ -0,0 +1,93 @@ +/* SPDX-License-Identifier: GPL-2.0+ */ +/* + * The driver for BMC side of SSIF interface + * + * Copyright (c) 2021, Ampere Computing LLC + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of + * the License, or (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program. If not, see <https://www.gnu.org/licenses/>. + */ +#ifndef __SSIF_BMC_H__ +#define __SSIF_BMC_H__ + +#define DEVICE_NAME "ipmi-ssif-host" + +#define GET_8BIT_ADDR(addr_7bit) (((addr_7bit) << 1) & 0xff) + +#define MSG_PAYLOAD_LEN_MAX 252 + +/* A standard SMBus Transaction is limited to 32 data bytes */ +#define MAX_PAYLOAD_PER_TRANSACTION 32 + +#define MAX_IPMI_DATA_PER_START_TRANSACTION 30 +#define MAX_IPMI_DATA_PER_MIDDLE_TRANSACTION 31 + +#define SSIF_IPMI_SINGLEPART_WRITE 0x2 +#define SSIF_IPMI_SINGLEPART_READ 0x3 +#define SSIF_IPMI_MULTIPART_WRITE_START 0x6 +#define SSIF_IPMI_MULTIPART_WRITE_MIDDLE 0x7 +#define SSIF_IPMI_MULTIPART_WRITE_END 0x8 +#define SSIF_IPMI_MULTIPART_READ_START 0x3 +#define SSIF_IPMI_MULTIPART_READ_MIDDLE 0x9 + +struct ssif_msg { + u8 len; + u8 netfn_lun; + u8 cmd; + u8 payload[MSG_PAYLOAD_LEN_MAX]; +} __packed; + +static inline u32 ssif_msg_len(struct ssif_msg *ssif_msg) +{ + return ssif_msg->len + 1; +} + +#define SSIF_BMC_BUSY 0x01 +#define SSIF_BMC_READY 0x02 + +struct ssif_bmc_ctx { + struct i2c_client *client; + struct miscdevice miscdev; + u8 running; + u8 smbus_cmd; + struct ssif_msg request; + bool request_available; + struct ssif_msg response; + bool response_in_progress; + /* Response buffer for Multi-part Read Transaction */ + u8 response_buf[MAX_PAYLOAD_PER_TRANSACTION]; + /* Flag to identify a Multi-part Read Transaction */ + bool is_singlepart_read; + u8 nbytes_processed; + u8 remain_len; + u8 recv_len; + /* Block Number of a Multi-part Read Transaction */ + u8 block_num; + size_t msg_idx; + enum i2c_slave_event last_event; + bool pec_support; + /* spinlock */ + spinlock_t lock; + wait_queue_head_t wait_queue; + void (*set_ssif_bmc_status)(struct ssif_bmc_ctx *ssif_bmc, unsigned int flags); + void *priv; +}; + +static inline struct ssif_bmc_ctx *to_ssif_bmc(struct file *file) +{ + return container_of(file->private_data, struct ssif_bmc_ctx, miscdev); +} + +struct ssif_bmc_ctx *ssif_bmc_alloc(struct i2c_client *client, int sizeof_priv); + +#endif /* __SSIF_BMC_H__ */
The SMBus system interface (SSIF) IPMI BMC driver can be used to perform in-band IPMI communication with their host in management (BMC) side. Signed-off-by: Quan Nguyen <quan@os.amperecomputing.com> --- v3: + Removed redundant license info [Joel] + Switched to use traditional if-else [Joel] + Removed unused ssif_bmc_ioctl() [Joel] + Made handle_request()/complete_response() to return void [Joel] + Refactored send_ssif_bmc_response()/receive_ssif_bmc_request() [Corey] + Removed mutex [Corey] + Use spin_lock/unlock_irqsave/restore in callback [Corey] + Removed the unnecessary memset [Corey] + Switch to use dev_err() [Corey] v2: + Fixed compiling error with COMPILE_TEST for arc drivers/char/ipmi/Kconfig | 11 + drivers/char/ipmi/Makefile | 1 + drivers/char/ipmi/ssif_bmc.c | 605 +++++++++++++++++++++++++++++++++++ drivers/char/ipmi/ssif_bmc.h | 93 ++++++ 4 files changed, 710 insertions(+) create mode 100644 drivers/char/ipmi/ssif_bmc.c create mode 100644 drivers/char/ipmi/ssif_bmc.h