From mboxrd@z Thu Jan 1 00:00:00 1970 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=-13.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 A212DC43461 for ; Wed, 19 May 2021 12:30:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 711E16124C for ; Wed, 19 May 2021 12:30:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1351960AbhESMcI (ORCPT ); Wed, 19 May 2021 08:32:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42316 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232850AbhESMcG (ORCPT ); Wed, 19 May 2021 08:32:06 -0400 Received: from mail-ot1-x332.google.com (mail-ot1-x332.google.com [IPv6:2607:f8b0:4864:20::332]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 768FDC06175F; Wed, 19 May 2021 05:30:46 -0700 (PDT) Received: by mail-ot1-x332.google.com with SMTP id i12-20020a05683033ecb02903346fa0f74dso937813otu.10; Wed, 19 May 2021 05:30:46 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:reply-to:references :mime-version:content-disposition:content-transfer-encoding :in-reply-to; bh=aKHr+1V+CDnfzSzbLj1hWsDUAY0cmFm/k2Vt/tEA6F8=; b=mS6dszP8bCc2Bg+C3HNJ90znzhnOLWLPWwIiOluenf/xCXlIEpAtt+46phu38p/Fwd 6eEb0hNH6g4T4MKxxgIqyzCgBs5WHfUPY9TSeC4WbfBgHoGSFDc/UDmAK9E9CA0wX7O6 z1J375Xmxq3LEb8QdLdZq8p5gFtUJS37C6E5P/+LYy2eqqNXQ0wlx8i0x1QmkWMizQ9x lqIxiiVb+5xD0JXUb9HkN4lQ81/NM71gwLE8cldY/aXtY4jpVAVhiLNUSgZvpuEV5QCc YUsCH/Dm9kwzqk48pzrWSDZzVvK5crEW+Np/tcOrpSIMQqgc/KxFD/NlKXezFylBmXYh poow== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :reply-to:references:mime-version:content-disposition :content-transfer-encoding:in-reply-to; bh=aKHr+1V+CDnfzSzbLj1hWsDUAY0cmFm/k2Vt/tEA6F8=; b=bgeuMXBagTXM3jzCsmQIfutOdn5DpgR7bzNkJiTTgsVt6EbK9JzSW4DWtMYgiKafTZ 0e41j/xPn52cWDap7eLEAGgoRIkDPTBXq8Ep1Eq7qsZChMp1lqdwFLjOHBmn05y896VX eIHHX8akvdfLrODjjuUaLY4gB+8UuSgZcN27kos7HJspZh24mdXaw2X6E0fz2kLcQakg hfh0EGgKrZowgXPetH9ofBDRAi/PUz8AWl6CMhAjkdemguoqNv1xENBSHzbPQkKDQcaz IbZTUsNssVPEe/8T7+FiksPmdQPM7+gUlavFuyMrUDmF7uEzGsh51q9iLPlGWz8pVKsH dOFw== X-Gm-Message-State: AOAM5307xHGygtnOjJpAOaoM8qkn03aOIXEgrFAVBeYTvZQj5IbEoO+H kMaJywjLLnJDRS8/2mZF8B6xyh9/pZgt X-Google-Smtp-Source: ABdhPJxOhBgHwUIx0RCQQWzAVbOph3yRvDgdajDuJH9n960Otk/URTgPiiYCbnqV6/LOlbQctg972Q== X-Received: by 2002:a05:6830:18fb:: with SMTP id d27mr8529362otf.235.1621427445589; Wed, 19 May 2021 05:30:45 -0700 (PDT) Received: from serve.minyard.net ([47.184.156.158]) by smtp.gmail.com with ESMTPSA id r2sm4471424otq.28.2021.05.19.05.30.44 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 19 May 2021 05:30:44 -0700 (PDT) Sender: Corey Minyard Received: from minyard.net (unknown [IPv6:2001:470:b8f6:1b:9144:ba66:ea13:f260]) by serve.minyard.net (Postfix) with ESMTPSA id 6AFE818000C; Wed, 19 May 2021 12:30:43 +0000 (UTC) Date: Wed, 19 May 2021 07:30:42 -0500 From: Corey Minyard To: Quan Nguyen Cc: Rob Herring , Joel Stanley , Andrew Jeffery , Brendan Higgins , Benjamin Herrenschmidt , Wolfram Sang , Philipp Zabel , openipmi-developer@lists.sourceforge.net, devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-aspeed@lists.ozlabs.org, linux-kernel@vger.kernel.org, linux-i2c@vger.kernel.org, Open Source Submission , Phong Vo , "Thang Q . Nguyen" , openbmc@lists.ozlabs.org Subject: Re: [PATCH v3 2/7] ipmi: ssif_bmc: Add SSIF BMC driver Message-ID: <20210519123042.GF2921206@minyard.net> Reply-To: minyard@acm.org References: <20210519074934.20712-1-quan@os.amperecomputing.com> <20210519074934.20712-3-quan@os.amperecomputing.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210519074934.20712-3-quan@os.amperecomputing.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 > --- > 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 > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#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 "); > +MODULE_AUTHOR("Quan Nguyen "); > +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 . > + */ > +#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 >