From patchwork Fri Mar 19 06:27:47 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Jeffery X-Patchwork-Id: 12150121 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-22.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 8E1C1C433DB for ; Fri, 19 Mar 2021 06:35:20 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 7D18764F6D for ; Fri, 19 Mar 2021 06:35:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7D18764F6D Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=aj.id.au Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=desiato.20200630; h=Sender:Content-Transfer-Encoding :Content-Type:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To:Message-Id:Date: Subject:Cc:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=z+RScMG45GJWwV8zELohyOs3/UmADfKpWZXWIJo4Unw=; b=Cf/Azc96CwBuz/4GK2I6A+CuQ p2Q3FMyKBEPRfqCFtQowUQiiaxxGnWyY6BGNp3Tcy4nl7SqbUX/gV7HJ1Vx2guwuAAeIGAJxA8xaU oa3z5/pDbI1g8hOo6goy0t49f/PE75HDzzXgfHPwLh1CdaqzKB4l+jnV6Crj5O9Q//zIkjUIYyYyj uhuMXVMjqNRdq+6l05m+Uoc5ewyvQ4EKw72JXoD99q9VGs8vhB4CwTE0ajftE4Wbo414PYj1yQdDH CbgV5gKMQSu1o4uUEgxxMQplZUiKa8xY/IL7wnTmA6Sbeb03v39j2IB0Ly4zShQBHkJrbLRIAMfpB VohNvxAbA==; Received: from localhost ([::1] helo=desiato.infradead.org) by desiato.infradead.org with esmtp (Exim 4.94 #2 (Red Hat Linux)) id 1lN8hQ-006fXU-On; Fri, 19 Mar 2021 06:33:33 +0000 Received: from new4-smtp.messagingengine.com ([66.111.4.230]) by desiato.infradead.org with esmtps (Exim 4.94 #2 (Red Hat Linux)) id 1lN8dv-006eAm-U5 for linux-arm-kernel@lists.infradead.org; Fri, 19 Mar 2021 06:30:01 +0000 Received: from compute3.internal (compute3.nyi.internal [10.202.2.43]) by mailnew.nyi.internal (Postfix) with ESMTP id 119DC580A81; Fri, 19 Mar 2021 02:29:55 -0400 (EDT) Received: from mailfrontend1 ([10.202.2.162]) by compute3.internal (MEProxy); Fri, 19 Mar 2021 02:29:55 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=aj.id.au; h=from :to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; s=fm2; bh=aQnNHewa5jTnB GjGVTD5mvjVD6p5J2c954frqWDzHlE=; b=q3XkDkYWzcRoGHuiO64SEX0218rb5 kyZ6m4h1iTXi61Yp4N7fUMoAR0BsBlm6tHdomMm3fSDvGsH25J5V2KpOdff0gGYx yEUpoxJVmn5AtwTsLhHpfXfbTmn8Kjtl6WPNOYwUjMscFbdhabR+1ssGXh0zUotL Er8EBGr7Om+ELe3XKZM0f8zAfSCKxNUuFYNRfe2Q7YaEZA2Tj62qsV51CGPvpzM3 /zh+7dWgHZYZxD/Jqb/V2deKI5HepQifCUxwWHUzro6sooyICt2PayezGT4Dcsh7 3MCej7jtFb+kTfBJAkyJyAy3MYuA0yzhJ73H5X6qvqRgAN/IsR/v0FJbQ== DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d= messagingengine.com; h=cc:content-transfer-encoding:date:from :in-reply-to:message-id:mime-version:references:subject:to :x-me-proxy:x-me-proxy:x-me-sender:x-me-sender:x-sasl-enc; s= fm2; bh=aQnNHewa5jTnBGjGVTD5mvjVD6p5J2c954frqWDzHlE=; b=J304m5Tr VWKuub7XG2k6keN4zBXCBWnY94BvFWaE/fCB4G35m6VhfWyFXGhn9n+TxfJYQNJI 7dKqjyTVgcyOXR85BdZ95TM8tdRlmj5QX1GzNupSPejLfeME7+XNmmhYa0xMQmGN MIioB4MwP37840Zfpzpz2VrO+LzMLGAgsEmFObIt9gLyIwsJicjUXXAcjEA0DXfG +DzwQbZoEQwjae+xXuKhAXxywslY4RONqN/MkNJjkoL0tyeWdcZaudO8Ael1gV9r VPtji1T1vZAr6j3umMiZ4QP0gx4tDoV5cbGZ796xDvfw8+6Q7JoStypM7D+4gKu8 SLrDvSnIIyAEDQ== X-ME-Sender: X-ME-Proxy-Cause: gggruggvucftvghtrhhoucdtuddrgeduledrudefjedgleeiucetufdoteggodetrfdotf fvucfrrhhofhhilhgvmecuhfgrshhtofgrihhlpdfqfgfvpdfurfetoffkrfgpnffqhgen uceurghilhhouhhtmecufedttdenucenucfjughrpefhvffufffkofgjfhgggfestdekre dtredttdenucfhrhhomheptehnughrvgifucflvghffhgvrhihuceorghnughrvgifsegr jhdrihgurdgruheqnecuggftrfgrthhtvghrnhepuefhtefhudeufeehffeffeetieeufe duleevgfekteefteekleetffehjeeukeehnecuffhomhgrihhnpehgihhthhhusgdrtgho mhenucfkphepuddukedrvddutddrudekuddrheehnecuvehluhhsthgvrhfuihiivgeptd enucfrrghrrghmpehmrghilhhfrhhomheprghnughrvgifsegrjhdrihgurdgruh X-ME-Proxy: Received: from localhost.localdomain (ppp118-210-181-55.adl-adc-lon-bras34.tpg.internode.on.net [118.210.181.55]) by mail.messagingengine.com (Postfix) with ESMTPA id 78253240057; Fri, 19 Mar 2021 02:29:49 -0400 (EDT) From: Andrew Jeffery To: openipmi-developer@lists.sourceforge.net, openbmc@lists.ozlabs.org, minyard@acm.org Cc: joel@jms.id.au, ryan_chen@aspeedtech.com, devicetree@vger.kernel.org, tmaimon77@gmail.com, linux-aspeed@lists.ozlabs.org, linux-gpio@vger.kernel.org, avifishman70@gmail.com, venture@google.com, linus.walleij@linaro.org, linux-kernel@vger.kernel.org, tali.perry1@gmail.com, robh+dt@kernel.org, lee.jones@linaro.org, chiawei_wang@aspeedtech.com, linux-arm-kernel@lists.infradead.org, benjaminfair@google.com Subject: [PATCH v2 16/21] ipmi: kcs_bmc: Add a "raw" character device interface Date: Fri, 19 Mar 2021 16:57:47 +1030 Message-Id: <20210319062752.145730-16-andrew@aj.id.au> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20210319062752.145730-1-andrew@aj.id.au> References: <20210319062752.145730-1-andrew@aj.id.au> MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210319_062956_531242_A03D3B0C X-CRM114-Status: GOOD ( 27.91 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org The existing IPMI chardev encodes IPMI behaviours as the name suggests. However, KCS devices are useful beyond IPMI (or keyboards), as they provide a means to generate IRQs and exchange arbitrary data between a BMC and its host system. Implement a "raw" KCS character device that exposes the IDR, ODR and STR registers to userspace via read() and write() implemented on a character device: +--------+--------+---------+ | Offset | read() | write() | +--------+--------+---------+ | 0 | IDR | ODR | +--------+--------+---------+ | 1 | STR | STR | +--------+--------+---------+ This interface allows userspace to implement arbitrary (though somewhat inefficient) protocols for exchanging information between a BMC and host firmware. Conceptually the KCS interface can be used as an out-of-band machanism for interrupt-signaled control messages while bulk data transfers occur over more appropriate interfaces between the BMC and the host (which may lack their own interrupt mechanism, e.g. LPC FW cycles). poll() is provided, which will wait for IBF or OBE conditions for data reads and writes respectively. Reads of STR on its own never blocks, though accessing both offsets in the one system call may block if the data registers are not ready. Signed-off-by: Andrew Jeffery --- Documentation/ABI/testing/dev-raw-kcs | 25 ++ drivers/char/ipmi/Kconfig | 17 + drivers/char/ipmi/Makefile | 1 + drivers/char/ipmi/kcs_bmc_cdev_raw.c | 443 ++++++++++++++++++++++++++ 4 files changed, 486 insertions(+) create mode 100644 Documentation/ABI/testing/dev-raw-kcs create mode 100644 drivers/char/ipmi/kcs_bmc_cdev_raw.c diff --git a/Documentation/ABI/testing/dev-raw-kcs b/Documentation/ABI/testing/dev-raw-kcs new file mode 100644 index 000000000000..06e7e2071562 --- /dev/null +++ b/Documentation/ABI/testing/dev-raw-kcs @@ -0,0 +1,25 @@ +What: /dev/raw-kcs* +Date: 2021-02-15 +KernelVersion: 5.13 +Contact: openbmc@lists.ozlabs.org +Contact: openipmi-developer@lists.sourceforge.net +Contact: Andrew Jeffery +Description: ``/dev/raw-kcs*`` exposes to userspace the data and + status registers of Keyboard-Controller-Style (KCS) IPMI + interfaces via read() and write() syscalls. Direct + exposure of the data and status registers enables + inefficient but arbitrary protocols to be implemented + over the device. A typical approach is to use KCS + devices for out-of-band signalling for bulk data + transfers over other interfaces between a Baseboard + Management Controller and its host. + + +--------+--------+---------+ + | Offset | read() | write() | + +--------+--------+---------+ + | 0 | IDR | ODR | + +--------+--------+---------+ + | 1 | STR | STR | + +--------+--------+---------+ + +Users: libmctp: https://github.com/openbmc/libmctp diff --git a/drivers/char/ipmi/Kconfig b/drivers/char/ipmi/Kconfig index bc5f81899b62..273ac1a1f870 100644 --- a/drivers/char/ipmi/Kconfig +++ b/drivers/char/ipmi/Kconfig @@ -137,6 +137,23 @@ config IPMI_KCS_BMC_CDEV_IPMI This support is also available as a module. The module will be called kcs_bmc_cdev_ipmi. +config IPMI_KCS_BMC_CDEV_RAW + depends on IPMI_KCS_BMC + tristate "Raw character device interface for BMC KCS devices" + help + Provides a BMC-side character device directly exposing the + data and status registers of a KCS device to userspace. While + KCS devices are commonly used to implement IPMI message + passing, they provide a general interface for exchange of + interrupts, data and status information between the BMC and + its host. + + Say YES if you wish to use the KCS devices to implement + protocols that are not IPMI. + + This support is also available as a module. The module will be + called kcs_bmc_cdev_raw. + config ASPEED_BT_IPMI_BMC depends on ARCH_ASPEED || COMPILE_TEST depends on REGMAP && REGMAP_MMIO && MFD_SYSCON diff --git a/drivers/char/ipmi/Makefile b/drivers/char/ipmi/Makefile index fcfa676afddb..c8cc248ddd90 100644 --- a/drivers/char/ipmi/Makefile +++ b/drivers/char/ipmi/Makefile @@ -24,6 +24,7 @@ obj-$(CONFIG_IPMI_WATCHDOG) += ipmi_watchdog.o obj-$(CONFIG_IPMI_POWEROFF) += ipmi_poweroff.o obj-$(CONFIG_IPMI_KCS_BMC) += kcs_bmc.o obj-$(CONFIG_IPMI_KCS_BMC_CDEV_IPMI) += kcs_bmc_cdev_ipmi.o +obj-$(CONFIG_IPMI_KCS_BMC_CDEV_RAW) += kcs_bmc_cdev_raw.o obj-$(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 diff --git a/drivers/char/ipmi/kcs_bmc_cdev_raw.c b/drivers/char/ipmi/kcs_bmc_cdev_raw.c new file mode 100644 index 000000000000..bdd258648c8e --- /dev/null +++ b/drivers/char/ipmi/kcs_bmc_cdev_raw.c @@ -0,0 +1,443 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* Copyright (c) 2021 IBM Corp. */ + +#include +#include +#include +#include +#include +#include +#include +#include + +#include "kcs_bmc_client.h" + +#define DEVICE_NAME "raw-kcs" + +struct kcs_bmc_raw { + struct list_head entry; + + struct kcs_bmc_client client; + + wait_queue_head_t queue; + u8 events; + bool writable; + bool readable; + u8 idr; + + struct miscdevice miscdev; +}; + +static inline struct kcs_bmc_raw *client_to_kcs_bmc_raw(struct kcs_bmc_client *client) +{ + return container_of(client, struct kcs_bmc_raw, client); +} + +/* Call under priv->queue.lock */ +static void kcs_bmc_raw_update_event_mask(struct kcs_bmc_raw *priv, u8 mask, u8 state) +{ + kcs_bmc_update_event_mask(priv->client.dev, mask, state); + priv->events &= ~mask; + priv->events |= state & mask; +} + +static int kcs_bmc_raw_event(struct kcs_bmc_client *client) +{ + struct kcs_bmc_raw *priv; + struct device *dev; + u8 status, handled; + + priv = client_to_kcs_bmc_raw(client); + dev = priv->miscdev.this_device; + + spin_lock(&priv->queue.lock); + + status = kcs_bmc_read_status(client->dev); + handled = 0; + + if ((priv->events & KCS_BMC_EVENT_TYPE_IBF) && (status & KCS_BMC_STR_IBF)) { + if (priv->readable) + dev_err(dev, "Storm brewing!"); + + dev_dbg(dev, "Disabling IDR events for back-pressure\n"); + kcs_bmc_raw_update_event_mask(priv, KCS_BMC_EVENT_TYPE_IBF, 0); + priv->idr = kcs_bmc_read_data(client->dev); + priv->readable = true; + + dev_dbg(dev, "IDR read, waking waiters\n"); + wake_up_locked(&priv->queue); + + handled |= KCS_BMC_EVENT_TYPE_IBF; + } + + if ((priv->events & KCS_BMC_EVENT_TYPE_OBE) && !(status & KCS_BMC_STR_OBF)) { + kcs_bmc_raw_update_event_mask(priv, KCS_BMC_EVENT_TYPE_OBE, 0); + priv->writable = true; + + dev_dbg(dev, "ODR writable, waking waiters\n"); + wake_up_locked(&priv->queue); + + handled |= KCS_BMC_EVENT_TYPE_OBE; + } + + spin_unlock(&priv->queue.lock); + + return handled ? KCS_BMC_EVENT_HANDLED : KCS_BMC_EVENT_NONE; +} + +static const struct kcs_bmc_client_ops kcs_bmc_raw_client_ops = { + .event = kcs_bmc_raw_event, +}; + +static inline struct kcs_bmc_raw *file_to_kcs_bmc_raw(struct file *filp) +{ + return container_of(filp->private_data, struct kcs_bmc_raw, miscdev); +} + +static int kcs_bmc_raw_open(struct inode *inode, struct file *filp) +{ + struct kcs_bmc_raw *priv = file_to_kcs_bmc_raw(filp); + + return kcs_bmc_enable_device(priv->client.dev, &priv->client); +} + +static bool kcs_bmc_raw_prepare_obe(struct kcs_bmc_raw *priv) +{ + bool writable; + + /* Enable the OBE event so we can catch the host clearing OBF */ + kcs_bmc_raw_update_event_mask(priv, KCS_BMC_EVENT_TYPE_OBE, KCS_BMC_EVENT_TYPE_OBE); + + /* Now that we'll catch an OBE event, check if it's already occurred */ + writable = !(kcs_bmc_read_status(priv->client.dev) & KCS_BMC_STR_OBF); + + /* If OBF is clear we've missed the OBE event, so disable it */ + if (writable) + kcs_bmc_raw_update_event_mask(priv, KCS_BMC_EVENT_TYPE_OBE, 0); + + return writable; +} + +static __poll_t kcs_bmc_raw_poll(struct file *filp, poll_table *wait) +{ + struct kcs_bmc_raw *priv; + __poll_t events = 0; + + priv = file_to_kcs_bmc_raw(filp); + + poll_wait(filp, &priv->queue, wait); + + spin_lock_irq(&priv->queue.lock); + if (kcs_bmc_raw_prepare_obe(priv)) + events |= (EPOLLOUT | EPOLLWRNORM); + + if (priv->readable || (kcs_bmc_read_status(priv->client.dev) & KCS_BMC_STR_IBF)) + events |= (EPOLLIN | EPOLLRDNORM); + spin_unlock_irq(&priv->queue.lock); + + return events; +} + +static ssize_t kcs_bmc_raw_read(struct file *filp, char __user *buf, + size_t count, loff_t *ppos) +{ + struct kcs_bmc_device *kcs_bmc; + struct kcs_bmc_raw *priv; + bool read_idr, read_str; + struct device *dev; + u8 idr, str; + ssize_t rc; + + priv = file_to_kcs_bmc_raw(filp); + kcs_bmc = priv->client.dev; + dev = priv->miscdev.this_device; + + if (!count) + return 0; + + if (count > 2 || *ppos > 1) + return -EINVAL; + + if (*ppos + count > 2) + return -EINVAL; + + read_idr = (*ppos == 0); + read_str = (*ppos == 1) || (count == 2); + + spin_lock_irq(&priv->queue.lock); + if (read_idr) { + dev_dbg(dev, "Waiting for IBF\n"); + str = kcs_bmc_read_status(kcs_bmc); + if ((filp->f_flags & O_NONBLOCK) && (str & KCS_BMC_STR_IBF)) { + rc = -EWOULDBLOCK; + goto out; + } + + rc = wait_event_interruptible_locked(priv->queue, + priv->readable || (str & KCS_BMC_STR_IBF)); + if (rc < 0) + goto out; + + if (signal_pending(current)) { + dev_dbg(dev, "Interrupted waiting for IBF\n"); + rc = -EINTR; + goto out; + } + + /* + * Re-enable events prior to possible read of IDR (which clears + * IBF) to ensure we receive interrupts for subsequent writes + * to IDR. Writes to IDR by the host should not occur while IBF + * is set. + */ + dev_dbg(dev, "Woken by IBF, enabling IRQ\n"); + kcs_bmc_raw_update_event_mask(priv, KCS_BMC_EVENT_TYPE_IBF, + KCS_BMC_EVENT_TYPE_IBF); + + /* Read data out of IDR into internal storage if necessary */ + if (!priv->readable) { + WARN(!(str & KCS_BMC_STR_IBF), "Unknown reason for wakeup!"); + + priv->idr = kcs_bmc_read_data(kcs_bmc); + } + + /* Copy data from internal storage to userspace */ + idr = priv->idr; + + /* We're done consuming the internally stored value */ + priv->readable = false; + } + + if (read_str) { + str = kcs_bmc_read_status(kcs_bmc); + if (*ppos == 0 || priv->readable) + /* + * If we got this far with `*ppos == 0` then we've read + * data out of IDR, so set IBF when reporting back to + * userspace so userspace knows the IDR value is valid. + */ + str |= KCS_BMC_STR_IBF; + + dev_dbg(dev, "Read status 0x%x\n", str); + + } + + rc = count; +out: + spin_unlock_irq(&priv->queue.lock); + + if (rc < 0) + return rc; + + /* Now copy the data in to the userspace buffer */ + + if (read_idr) + if (copy_to_user(buf++, &idr, sizeof(idr))) + return -EFAULT; + + if (read_str) + if (copy_to_user(buf, &str, sizeof(str))) + return -EFAULT; + + return count; +} + +static ssize_t kcs_bmc_raw_write(struct file *filp, const char __user *buf, + size_t count, loff_t *ppos) +{ + struct kcs_bmc_device *kcs_bmc; + bool write_odr, write_str; + struct kcs_bmc_raw *priv; + struct device *dev; + uint8_t data[2]; + ssize_t result; + u8 str; + + priv = file_to_kcs_bmc_raw(filp); + kcs_bmc = priv->client.dev; + dev = priv->miscdev.this_device; + + if (!count) + return count; + + if (count > 2) + return -EINVAL; + + if (*ppos >= 2) + return -EINVAL; + + if (*ppos + count > 2) + return -EINVAL; + + if (copy_from_user(data, buf, count)) + return -EFAULT; + + write_odr = (*ppos == 0); + write_str = (*ppos == 1) || (count == 2); + + spin_lock_irq(&priv->queue.lock); + + /* Always write status before data, we generate the SerIRQ by writing ODR */ + if (write_str) { + /* The index of STR in the userspace buffer depends on whether ODR is written */ + str = data[*ppos == 0]; + if (!(str & KCS_BMC_STR_OBF)) + dev_warn(dev, "Clearing OBF with status write: 0x%x\n", str); + dev_dbg(dev, "Writing status 0x%x\n", str); + kcs_bmc_write_status(kcs_bmc, str); + } + + if (write_odr) { + /* If we're writing ODR it's always the first byte in the buffer */ + u8 odr = data[0]; + + str = kcs_bmc_read_status(kcs_bmc); + if (str & KCS_BMC_STR_OBF) { + if (filp->f_flags & O_NONBLOCK) { + result = -EWOULDBLOCK; + goto out; + } + + priv->writable = kcs_bmc_raw_prepare_obe(priv); + + /* Now either OBF is already clear, or we'll get an OBE event to wake us */ + dev_dbg(dev, "Waiting for OBF to clear\n"); + wait_event_interruptible_locked(priv->queue, priv->writable); + + if (signal_pending(current)) { + kcs_bmc_raw_update_event_mask(priv, KCS_BMC_EVENT_TYPE_OBE, 0); + result = -EINTR; + goto out; + } + + WARN_ON(kcs_bmc_read_status(kcs_bmc) & KCS_BMC_STR_OBF); + } + + dev_dbg(dev, "Writing 0x%x to ODR\n", odr); + kcs_bmc_write_data(kcs_bmc, odr); + } + + result = count; +out: + spin_unlock_irq(&priv->queue.lock); + + return result; +} + +static int kcs_bmc_raw_release(struct inode *inode, struct file *filp) +{ + struct kcs_bmc_raw *priv = file_to_kcs_bmc_raw(filp); + + kcs_bmc_disable_device(priv->client.dev, &priv->client); + + return 0; +} + +static const struct file_operations kcs_bmc_raw_fops = { + .owner = THIS_MODULE, + .open = kcs_bmc_raw_open, + .llseek = no_seek_end_llseek, + .read = kcs_bmc_raw_read, + .write = kcs_bmc_raw_write, + .poll = kcs_bmc_raw_poll, + .release = kcs_bmc_raw_release, +}; + +static DEFINE_SPINLOCK(kcs_bmc_raw_instances_lock); +static LIST_HEAD(kcs_bmc_raw_instances); + +static int kcs_bmc_raw_attach_cdev(struct kcs_bmc_device *kcs_bmc) +{ + struct kcs_bmc_raw *priv; + int rc; + + priv = devm_kzalloc(kcs_bmc->dev, sizeof(*priv), GFP_KERNEL); + if (!priv) + return -ENOMEM; + + priv->client.dev = kcs_bmc; + priv->client.ops = &kcs_bmc_raw_client_ops; + + init_waitqueue_head(&priv->queue); + priv->writable = false; + priv->readable = false; + + priv->miscdev.minor = MISC_DYNAMIC_MINOR; + priv->miscdev.name = devm_kasprintf(kcs_bmc->dev, GFP_KERNEL, "%s%u", DEVICE_NAME, + kcs_bmc->channel); + if (!priv->miscdev.name) + return -EINVAL; + + priv->miscdev.fops = &kcs_bmc_raw_fops; + + /* Initialise our expected events. Listen for IBF but ignore OBE until necessary */ + kcs_bmc_raw_update_event_mask(priv, (KCS_BMC_EVENT_TYPE_IBF | KCS_BMC_EVENT_TYPE_OBE), + KCS_BMC_EVENT_TYPE_IBF); + + rc = misc_register(&priv->miscdev); + if (rc) { + dev_err(kcs_bmc->dev, "Unable to register device\n"); + return rc; + } + + spin_lock_irq(&kcs_bmc_raw_instances_lock); + list_add(&priv->entry, &kcs_bmc_raw_instances); + spin_unlock_irq(&kcs_bmc_raw_instances_lock); + + dev_info(kcs_bmc->dev, "Initialised raw client for channel %d", kcs_bmc->channel); + + return 0; +} + +static int kcs_bmc_raw_detach_cdev(struct kcs_bmc_device *kcs_bmc) +{ + struct kcs_bmc_raw *priv = NULL, *pos; + + spin_lock_irq(&kcs_bmc_raw_instances_lock); + list_for_each_entry(pos, &kcs_bmc_raw_instances, entry) { + if (pos->client.dev == kcs_bmc) { + priv = pos; + list_del(&pos->entry); + break; + } + } + spin_unlock_irq(&kcs_bmc_raw_instances_lock); + + if (!priv) + return 0; + + misc_deregister(&priv->miscdev); + kcs_bmc_disable_device(kcs_bmc, &priv->client); + devm_kfree(priv->client.dev->dev, priv); + + return 0; +} + +static const struct kcs_bmc_cdev_ops kcs_bmc_raw_cdev_ops = { + .add_device = kcs_bmc_raw_attach_cdev, + .remove_device = kcs_bmc_raw_detach_cdev, +}; + +static struct kcs_bmc_cdev kcs_bmc_raw_cdev = { + .ops = &kcs_bmc_raw_cdev_ops, +}; + +static int kcs_bmc_raw_init(void) +{ + return kcs_bmc_register_cdev(&kcs_bmc_raw_cdev); +} +module_init(kcs_bmc_raw_init); + +static void kcs_bmc_raw_exit(void) +{ + int rc; + + rc = kcs_bmc_unregister_cdev(&kcs_bmc_raw_cdev); + if (rc) + pr_warn("Failed to remove KCS BMC client: %d", rc); +} +module_exit(kcs_bmc_raw_exit); + +MODULE_LICENSE("GPL v2"); +MODULE_AUTHOR("Andrew Jeffery "); +MODULE_DESCRIPTION("Character device for raw access to a KCS device");