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Sat, 03 Apr 2021 15:28:30 -0700 (PDT) Date: Sat, 3 Apr 2021 15:28:10 -0700 In-Reply-To: <20210403222810.3481372-1-venture@google.com> Message-Id: <20210403222810.3481372-3-venture@google.com> Mime-Version: 1.0 References: <20210403222810.3481372-1-venture@google.com> X-Mailer: git-send-email 2.31.0.208.g409f899ff0-goog Subject: [PATCH 2/2] hw/i2c: add pca954x i2c-mux switch From: Patrick Venture To: cminyard@mvista.com, wuhaotsh@google.com, hskinnemoen@google.com Cc: qemu-arm@nongnu.org, qemu-devel@nongnu.org, Patrick Venture Received-SPF: pass client-ip=2607:f8b0:4864:20::b4a; envelope-from=3DuxoYAcKCpMI1AGHE13BB381.zB9D19H-01I18ABA3AH.BE3@flex--venture.bounces.google.com; helo=mail-yb1-xb4a.google.com X-Spam_score_int: -95 X-Spam_score: -9.6 X-Spam_bar: --------- X-Spam_report: (-9.6 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_MED=-0.001, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, USER_IN_DEF_DKIM_WL=-7.5 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" The pca954x is an i2c mux, and this adds support for two variants of this device: the pca9546 and pca9548. This device is very common on BMCs to route a different channel to each PCIe i2c bus downstream from the BMC. Signed-off-by: Patrick Venture Reviewed-by: Havard Skinnemoen Reviewed-by: Hao Wu --- MAINTAINERS | 6 + hw/i2c/Kconfig | 4 + hw/i2c/i2c_mux_pca954x.c | 182 +++++++++++++++++++++++++++++++ hw/i2c/meson.build | 1 + hw/i2c/trace-events | 5 + include/hw/i2c/i2c_mux_pca954x.h | 60 ++++++++++ 6 files changed, 258 insertions(+) create mode 100644 hw/i2c/i2c_mux_pca954x.c create mode 100644 include/hw/i2c/i2c_mux_pca954x.h diff --git a/MAINTAINERS b/MAINTAINERS index 69003cdc3c..6cec2a9320 100644 --- a/MAINTAINERS +++ b/MAINTAINERS @@ -2040,6 +2040,12 @@ S: Maintained F: hw/net/tulip.c F: hw/net/tulip.h +pca954x +M: Patrick Venture +S: Maintained +F: hw/i2c/i2c_mux_pca954x.c +F: include/hw/i2c/i2c_mux_pca954x.h + Generic Loader M: Alistair Francis S: Maintained diff --git a/hw/i2c/Kconfig b/hw/i2c/Kconfig index 09642a6dcb..8d120a25d5 100644 --- a/hw/i2c/Kconfig +++ b/hw/i2c/Kconfig @@ -28,3 +28,7 @@ config IMX_I2C config MPC_I2C bool select I2C + +config PCA954X + bool + select I2C diff --git a/hw/i2c/i2c_mux_pca954x.c b/hw/i2c/i2c_mux_pca954x.c new file mode 100644 index 0000000000..8017913637 --- /dev/null +++ b/hw/i2c/i2c_mux_pca954x.c @@ -0,0 +1,182 @@ +/* + * I2C multiplexer for PCA954x series of I2C multiplexer/switch chips. + * + * Copyright 2021 Google 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. + */ + +#include "qemu/osdep.h" +#include "qapi/error.h" +#include "hw/i2c/i2c_mux_pca954x.h" +#include "hw/i2c/smbus_slave.h" +#include "hw/qdev-core.h" +#include "qemu/log.h" +#include "qemu/module.h" +#include "qemu/queue.h" +#include "trace.h" + +int pca954x_add_child(I2CSlave *mux, uint8_t channel, I2CSlave *child) +{ + g_autofree char *name = NULL; + /* + * Ok, so we need to try to add the i2c_dev to channel for mux. + * A channel can have multiple devices, we need a list for each channel. + */ + Pca954xClass *pc = PCA954X_GET_CLASS(mux); + Pca954xState *pca954x = PCA954X(mux); + PcaMuxChild *controlled_device; + + /* Is the channel legal? */ + if (channel >= pc->nchans) { + return -1; + } + + controlled_device = g_new0(PcaMuxChild, 1); + controlled_device->channel = channel; + controlled_device->child = child; + object_ref(OBJECT(controlled_device->child)); + + /* Hide the device. */ + child->reachable = 0; + + QSLIST_INSERT_HEAD(&pca954x->children, controlled_device, sibling); + + name = g_strdup_printf("i2c@%u-child[%u]", channel, + pca954x->count[channel]); + object_property_add_link(OBJECT(mux), name, + object_get_typename(OBJECT(child)), + (Object **)&controlled_device->child, + NULL, /* read-only property */ + 0); + pca954x->count[channel]++; + + return 0; +} + +static void pca954x_enable_channel(Pca954xState *s, uint8_t enable_mask) +{ + PcaMuxChild *kid; + I2CSlave *child; + + /* + * For each child, check if their bit is set in data and if yes, enable + * them, otherwise disable, hide them. + */ + QSLIST_FOREACH(kid, &s->children, sibling) { + child = I2C_SLAVE(kid->child); + if (enable_mask & (1 << kid->channel)) { + child->reachable = true; + } else { + child->reachable = false; + } + } +} + +static void pca954x_write(Pca954xState *s, uint8_t data) +{ + s->control = data; + pca954x_enable_channel(s, data); + + trace_pca954x_write_bytes(data); +} + +static int pca954x_write_data(SMBusDevice *d, uint8_t *buf, uint8_t len) +{ + Pca954xState *s = PCA954X(d); + + if (len == 0) { + qemu_log_mask(LOG_GUEST_ERROR, "%s: writing empty data\n", __func__); + return -1; + } + + /* + * len should be 1, because they write one byte to enable/disable channels. + */ + if (len > 1) { + qemu_log_mask(LOG_GUEST_ERROR, + "%s: extra data after channel selection mask\n", + __func__); + return -1; + } + + pca954x_write(s, buf[0]); + return 0; +} + +static uint8_t pca954x_read_byte(SMBusDevice *d) +{ + Pca954xState *s = PCA954X(d); + uint8_t data = s->control; + trace_pca954x_read_data(data); + return data; +} + +static void pca9546_class_init(ObjectClass *oc, void *data) +{ + Pca954xClass *s = PCA954X_CLASS(oc); + s->nchans = PCA9546_CHANNEL_COUNT; +} + +static void pca9548_class_init(ObjectClass *oc, void *data) +{ + Pca954xClass *s = PCA954X_CLASS(oc); + s->nchans = PCA9548_CHANNEL_COUNT; +} + +static void pca954x_enter_reset(Object *obj, ResetType type) +{ + Pca954xState *s = PCA954X(obj); + /* Reset will disable all channels. */ + pca954x_write(s, 0); +} + +static void pca954x_init(Object *obj) +{ + Pca954xState *s = PCA954X(obj); + memset(s->count, 0x00, sizeof(s->count)); +} + +static void pca954x_class_init(ObjectClass *klass, void *data) +{ + ResettableClass *rc = RESETTABLE_CLASS(klass); + DeviceClass *dc = DEVICE_CLASS(klass); + SMBusDeviceClass *k = SMBUS_DEVICE_CLASS(klass); + + dc->desc = "Pca954x i2c-mux"; + k->write_data = pca954x_write_data; + k->receive_byte = pca954x_read_byte; + rc->phases.enter = pca954x_enter_reset; +} + +static const TypeInfo pca954x_info[] = { + { + .name = TYPE_PCA954X, + .parent = TYPE_SMBUS_DEVICE, + .instance_size = sizeof(Pca954xState), + .instance_init = pca954x_init, + .class_size = sizeof(Pca954xClass), + .class_init = pca954x_class_init, + .abstract = true, + }, + { + .name = TYPE_PCA9546, + .parent = TYPE_PCA954X, + .class_init = pca9546_class_init, + }, + { + .name = TYPE_PCA9548, + .parent = TYPE_PCA954X, + .class_init = pca9548_class_init, + }, +}; + +DEFINE_TYPES(pca954x_info) diff --git a/hw/i2c/meson.build b/hw/i2c/meson.build index cdcd694a7f..dd3aef02b2 100644 --- a/hw/i2c/meson.build +++ b/hw/i2c/meson.build @@ -14,4 +14,5 @@ i2c_ss.add(when: 'CONFIG_SMBUS_EEPROM', if_true: files('smbus_eeprom.c')) i2c_ss.add(when: 'CONFIG_VERSATILE_I2C', if_true: files('versatile_i2c.c')) i2c_ss.add(when: 'CONFIG_OMAP', if_true: files('omap_i2c.c')) i2c_ss.add(when: 'CONFIG_PPC4XX', if_true: files('ppc4xx_i2c.c')) +i2c_ss.add(when: 'CONFIG_PCA954X', if_true: files('i2c_mux_pca954x.c')) softmmu_ss.add_all(when: 'CONFIG_I2C', if_true: i2c_ss) diff --git a/hw/i2c/trace-events b/hw/i2c/trace-events index 82fe6f965f..82f19e6a2d 100644 --- a/hw/i2c/trace-events +++ b/hw/i2c/trace-events @@ -26,3 +26,8 @@ npcm7xx_smbus_recv_byte(const char *id, uint8_t value) "%s recv byte: 0x%02x" npcm7xx_smbus_stop(const char *id) "%s stopping" npcm7xx_smbus_nack(const char *id) "%s nacking" npcm7xx_smbus_recv_fifo(const char *id, uint8_t received, uint8_t expected) "%s recv fifo: received %u, expected %u" + +# i2c-mux-pca954x.c + +pca954x_write_bytes(uint8_t value) "PCA954X write data: 0x%02x" +pca954x_read_data(uint8_t value) "PCA954X read data: 0x%02x" diff --git a/include/hw/i2c/i2c_mux_pca954x.h b/include/hw/i2c/i2c_mux_pca954x.h new file mode 100644 index 0000000000..4ea240af26 --- /dev/null +++ b/include/hw/i2c/i2c_mux_pca954x.h @@ -0,0 +1,60 @@ +#ifndef QEMU_I2C_MUX_PCA954X +#define QEMU_I2C_MUX_PCA954X + +#include "hw/qdev-core.h" +#include "hw/i2c/i2c.h" +#include "hw/i2c/smbus_slave.h" + +#define PCA9548_CHANNEL_COUNT 8 +#define PCA9546_CHANNEL_COUNT 4 + +/* The i2c mux shares ownership of a bus child. */ +typedef struct PcaMuxChild { + I2CSlave *child; + + /* The channel on which this child lives. */ + uint8_t channel; + + QSLIST_ENTRY(PcaMuxChild) sibling; +} PcaMuxChild; + +typedef struct Pca954xState { + SMBusDevice parent; + + uint8_t control; + + /* The children this mux co-owns with its parent bus. */ + QSLIST_HEAD(, PcaMuxChild) children; + + /* The number of children per channel. */ + unsigned int count[PCA9548_CHANNEL_COUNT]; +} Pca954xState; + +typedef struct Pca954xClass { + SMBusDeviceClass parent; + + /* The number of channels this mux has. */ + uint8_t nchans; +} Pca954xClass; + +#define TYPE_PCA9546 "pca9546" +#define TYPE_PCA9548 "pca9548" + +#define TYPE_PCA954X "pca954x" + +#define PCA954X(obj) OBJECT_CHECK(Pca954xState, (obj), TYPE_PCA954X) +#define PCA954X_CLASS(klass) \ + OBJECT_CLASS_CHECK(Pca954xClass, (klass), TYPE_PCA954X) +#define PCA954X_GET_CLASS(obj) \ + OBJECT_GET_CLASS(Pca954xClass, (obj), TYPE_PCA954X) + +/** + * pca954x_add_child - Adds a child i2c device to the mux device on the + * specified channel. + * @mux - The i2c mux to control this child. + * @channel - The channel of the i2c mux that gates this child. + * @child - The i2c child device to add to the mux. + */ +int pca954x_add_child(I2CSlave *mux, uint8_t channel, I2CSlave *child); + +#endif