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=-16.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 516E2C4707D for ; Fri, 21 May 2021 19:58:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 24894613EB for ; Fri, 21 May 2021 19:58:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229643AbhEUT7W (ORCPT ); Fri, 21 May 2021 15:59:22 -0400 Received: from mail.kernel.org ([198.145.29.99]:46984 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229539AbhEUT7W (ORCPT ); Fri, 21 May 2021 15:59:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 2E684613E9; Fri, 21 May 2021 19:57:58 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621627078; bh=R85L7FsUZ70oPKqFuXqZjXi0iJ2S+ImYf+pwmy2Kouc=; h=Date:From:To:Cc:Subject:In-Reply-To:From; b=XmcAbiE3M0SLry3ARsdB3is2sSc0SNmQSf2scvFRaAYEa9eAePpjwccOrzpxSykLn NbV4tFtrlFRNUuGcfWMAtE5sJvwO5td8Kwo9LW/CNZZF5yhZIecMkj27dYZVUKfaW2 sYX/HSxQSlnSigBNfKGi5WVEuDiHhtiVbcEX+nUUs/o3R6gw6kS6Whri4TlmYsLtPd 7/EwRrwYwo2YgH7JwOCamyq4iWKrjH8qWEM706KiPw2A7W6D8JMfGrojr2sulyf+Or W4qUs/Da8334dA9sd12JgQtEJKcSxWKbW3sNglEdNR1xaJ8XrK/v476Usw4k0Xp7Fy QawDZP/HGvQ8g== Date: Fri, 21 May 2021 14:57:56 -0500 From: Bjorn Helgaas To: Shradha Todi Cc: linux-pci@vger.kernel.org, linux-kernel@vger.kernel.org, jingoohan1@gmail.com, gustavo.pimentel@synopsys.com, lorenzo.pieralisi@arm.com, robh@kernel.org, bhelgaas@google.com, pankaj.dubey@samsung.com, p.rajanbabu@samsung.com, hari.tv@samsung.com, niyas.ahmed@samsung.com, l.mehra@samsung.com Subject: Re: [PATCH 2/3] PCI: debugfs: Add support for RAS framework in DWC Message-ID: <20210521195756.GA365608@bjorn-Precision-5520> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210518174618.42089-3-shradha.t@samsung.com> Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org On Tue, May 18, 2021 at 11:16:17PM +0530, Shradha Todi wrote: > RAS is a vendor specific extended PCIe capability which which helps to read > hardware internal state. > > This framework support provides debugfs entries to use these features for > DesignWare controller. Following primary features of DesignWare controllers > are provided to userspace via debugfs: > - Debug registers > - Error injection > - Statistical counters > > Signed-off-by: Shradha Todi > --- > drivers/pci/controller/dwc/Kconfig | 9 + > drivers/pci/controller/dwc/Makefile | 1 + > .../controller/dwc/pcie-designware-debugfs.c | 544 ++++++++++++++++++ > .../controller/dwc/pcie-designware-debugfs.h | 133 +++++ > drivers/pci/controller/dwc/pcie-designware.h | 1 + > 5 files changed, 688 insertions(+) > create mode 100644 drivers/pci/controller/dwc/pcie-designware-debugfs.c > create mode 100644 drivers/pci/controller/dwc/pcie-designware-debugfs.h > > diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig > index 423d35872ce4..2d0a18cb9418 100644 > --- a/drivers/pci/controller/dwc/Kconfig > +++ b/drivers/pci/controller/dwc/Kconfig > @@ -6,6 +6,15 @@ menu "DesignWare PCI Core Support" > config PCIE_DW > bool > > +config PCIE_DW_DEBUGFS > + bool "DWC PCIe debugfs entries" > + default n > + help > + Enables debugfs entries for the DWC PCIe Controller. > + These entries make use of the RAS DES features in the DW > + controller to help in debug, error injection and statistical > + counters Maybe omit "DES"? The rest of the sentence spells it out, but the connection isn't completely obvious, and I don't think the first "DES" adds anything. > + > config PCIE_DW_HOST > bool > depends on PCI_MSI_IRQ_DOMAIN > diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile > index eca805c1a023..6ad12638f793 100644 > --- a/drivers/pci/controller/dwc/Makefile > +++ b/drivers/pci/controller/dwc/Makefile > @@ -1,5 +1,6 @@ > # SPDX-License-Identifier: GPL-2.0 > obj-$(CONFIG_PCIE_DW) += pcie-designware.o > +obj-$(CONFIG_PCIE_DW_DEBUGFS) += pcie-designware-debugfs.o > obj-$(CONFIG_PCIE_DW_HOST) += pcie-designware-host.o > obj-$(CONFIG_PCIE_DW_EP) += pcie-designware-ep.o > obj-$(CONFIG_PCIE_DW_PLAT) += pcie-designware-plat.o > diff --git a/drivers/pci/controller/dwc/pcie-designware-debugfs.c b/drivers/pci/controller/dwc/pcie-designware-debugfs.c > new file mode 100644 > index 000000000000..84bf196df240 > --- /dev/null > +++ b/drivers/pci/controller/dwc/pcie-designware-debugfs.c > @@ -0,0 +1,544 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Synopsys DesignWare PCIe controller debugfs driver > + * > + * Copyright (C) 2021 Samsung Electronics Co., Ltd. > + * http://www.samsung.com > + * > + * Author: Shradha Todi > + */ > + > +#include > +#include > +#include > +#include > +#include > +#include > +#include > +#include > + > +#include "pcie-designware.h" > +#include "pcie-designware-debugfs.h" > + > +#define DEBUGFS_BUF_MAX_SIZE 100 > + > +static char debugfs_buf[DEBUGFS_BUF_MAX_SIZE]; Should not be static, file scope. More comments below. > +static struct dentry *dir; > +static struct dentry *sub_dir; These should not be static, file scope either. I think "dir" should be returned by create_debugfs_files(), and the caller should hang onto it until it needs it for remove_debugfs_files(). "sub_dir" looks like it's only needed inside create_debugfs_files(), so it should be a local variable there. > +static struct event_counters ras_events[] = { > + {"ebuf_overflow", ebuf_overflow}, > + {"ebuf_underrun", ebuf_underrun}, > + {"decode_error", decode_error}, > + {"sync_header_error", sync_header_error}, > + {"receiver_error", receiver_error}, > + {"framing_error", framing_error}, > + {"lcrc_error", lcrc_error}, > + {"ecrc_error", ecrc_error}, > + {"unsupp_req_error", unsupp_req_error}, > + {"cmpltr_abort_error", cmpltr_abort_error}, > + {"cmpltn_timeout_error", cmpltn_timeout_error}, > + {"tx_l0s_entry", tx_l0s_entry}, > + {"rx_l0s_entry", rx_l0s_entry}, > + {"l1_entry", l1_entry}, > + {"l1_1_entry", l1_1_entry}, > + {"l1_2_entry", l1_2_entry}, > + {"l2_entry", l2_entry}, > + {"speed_change", speed_change}, > + {"width_chage", width_chage}, > + {0, 0}, > +}; > + > +static struct error_injections error_list[] = { > + {"tx_lcrc", tx_lcrc}, > + {"tx_ecrc", tx_ecrc}, > + {"rx_lcrc", rx_lcrc}, > + {"rx_ecrc", rx_ecrc}, > + {0, 0}, > +}; > + > +static int open(struct inode *inode, struct file *file) > +{ > + file->private_data = inode->i_private; > + > + return 0; > +} > + > +/* > + * set_event_number: Function to set event number based on filename > + * > + * This function is called from the common read and write function > + * written for all event counters. Using the debugfs filname, the > + * group number and event number for the counter is extracted and > + * then programmed into the control register. You can omit the "Function to" text here (more occurrences below). You can also omit the "This function is " text. It's obvious that this comment applies to this function. > + * > + * @file: file pointer to the debugfs entry > + * > + * Return: void > + */ > +static void set_event_number(struct file *file) > +{ > + int i; > + u32 val; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + u32 max_size = sizeof(ras_events) / sizeof(struct event_counters); Reorder the local decls here and below like this: struct dw_pcie *pci = file->private_data; int i; u32 val; so things are in the order they're used. It's fairly conventional to look up things based on incoming parameters first, e.g., the "struct dw_pcie *pci = file->private_data;" (no cast needed there). > + for (i = 0; i < max_size; i++) { Drop "max_size" and use this instead: for (i = 0; i < ARRAY_SIZE(ras_events); i++) { > + if (strcmp(ras_events[i].name, > + file->f_path.dentry->d_parent->d_iname) == 0) { There are *very* few uses of d_iname in the tree, which makes me think you're doing something wrong here. I don't have a suggestion yet, but maybe take a look at other debugfs users to see if there's a common pattern you can copy? > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + > + RAS_DES_EVENT_COUNTER_CTRL_REG); > + val &= ~(EVENT_COUNTER_ENABLE); Unnecessary parentheses. > + val &= ~(0xFFF << 16); > + val |= (ras_events[i].event_num << 16); > + dw_pcie_writel_dbi(pci, pci->ras_cap_offset + > + RAS_DES_EVENT_COUNTER_CTRL_REG, val); > + break; > + } > + } > +} Add blank line here. > +/* > + * get_error_inj_number: Function to get error number based on filename > + * > + * This function is called from the common read and write function > + * written for all error injection debugfs entries. Using the debugfs > + * filname, the error group and type of error to be injected is extracted. > + * > + * @file: file pointer to the debugfs entry > + * > + * Return: u32 > + * [31:8]: Type of error to be injected > + * [7:0]: Group of error it belongs to > + */ > + Remove spurious blank line above. > +static u32 get_error_inj_number(struct file *file) > +{ > + int i; > + u32 max_size = sizeof(error_list) / sizeof(struct error_injections); Drop "max_size" and use ARRAY_SIZE() again. > + for (i = 0; i < max_size; i++) { > + if (strcmp(error_list[i].name, > + file->f_path.dentry->d_iname) == 0) { > + return error_list[i].type_of_err; > + } > + } > + > + return 0; > +} > + > +/* > + * ras_event_counter_en_read: Function to get if counter is enable > + * > + * This function is invoked when the following command is made: > + * cat /sys/kernel/debug/dwc_pcie_plat/ras_des_counter//counter_enable > + * It returns whether the counter is enabled or not > + */ > +static ssize_t ras_event_counter_en_read(struct file *file, char __user *buf, > + size_t count, loff_t *ppos) > +{ > + u32 ret; > + u32 val; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; Unnecessary cast, reorder decls (more occurrences below). > + set_event_number(file); > + > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + > + RAS_DES_EVENT_COUNTER_CTRL_REG); This *looks* like it might require mutual exclusion around the "set_event_number(); dw_pcie_readl_dbi();" pair. Does set_event_number() write a register that determines which counter dw_pcie_readl_dbi() will read? If so, that should be made atomic somehow. > + val = (val >> EVENT_COUNTER_STATUS_SHIFT) & EVENT_COUNTER_STATUS_MASK; > + if (val) > + sprintf(debugfs_buf, "Enabled\n"); > + else > + sprintf(debugfs_buf, "Disabled\n"); > + > + ret = simple_read_from_buffer(buf, count, ppos, debugfs_buf, > + strlen(debugfs_buf)); I don't feel confident about this because: - "debugfs_buf" is static and shared among all these users without any obvious mutual exclusion, and - sprintf() is a notorious problem for buffer overflows. This isn't a problem here, but it does require extra effort to validate. I think it would be better to use scnprintf(), which also has the benefit of returning the value you need to pass to simple_read_from_buffer(), so you don't need the strlen(). drivers/ntb/test/ntb_tool.c has lots of examples you could copy. I don't *think* you have any buffer overflow issues in this file, but you also don't seem to ever print more than a dozen or so characters. Using buffers on the stack would be simple and make it obvious that there are no mutual exclusion issues. > + > + return ret; return simple_read_from_buffer(...); and drop "ret" (also more occurrences below). > +} > + > +/* > + * ras_event_counter_lane_sel_read: Function to get lane number selected > + * > + * This function is invoked when the following command is made: > + * cat /sys/kernel/debug/dwc_pcie_plat/ras_des_counter//lane_select > + * It returns for which lane the counter configurations are done > + */ > +static ssize_t ras_event_counter_lane_sel_read(struct file *file, > + char __user *buf, size_t count, > + loff_t *ppos) > +{ > + u32 ret; > + u32 val; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + > + set_event_number(file); > + > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + > + RAS_DES_EVENT_COUNTER_CTRL_REG); > + val = (val >> LANE_SELECT_SHIFT) & LANE_SELECT_MASK; > + sprintf(debugfs_buf, "0x%x\n", val); I always use "%#x" because it's a tiny bit shorter and avoids the possibility of typos like "0X%x" or "0x%X", which would produce "0Xabcd" or "0xABCD". Weird personal idiosyncracy :) > + ret = simple_read_from_buffer(buf, count, ppos, debugfs_buf, > + strlen(debugfs_buf)); > + > + return ret; > +} > + > +/* > + * ras_event_counter_value_read: Function to get counter value > + * > + * This function is invoked when the following command is made: > + * cat /sys/kernel/debug/dwc_pcie_plat/ras_des_counter//counter_value > + * It returns the number of time the selected event has happened if enabled > + */ > + Remove spurious blank line above. > +static ssize_t ras_event_counter_value_read(struct file *file, char __user *buf, > + size_t count, loff_t *ppos) > +{ > + u32 ret; > + u32 val; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + > + set_event_number(file); > + > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + > + RAS_DES_EVENT_COUNTER_DATA_REG); > + sprintf(debugfs_buf, "0x%x\n", val); > + ret = simple_read_from_buffer(buf, count, ppos, debugfs_buf, > + strlen(debugfs_buf)); > + > + return ret; > +} > + > +/* > + * ras_event_counter_en_write: Function to set if counter is enable > + * > + * This function is invoked when the following command is made: > + * echo n > /sys/kernel/debug/dwc_pcie_plat/ > + * ras_des_counter//counter_enable > + * Here n can be 1 to enable and 0 to disable > + */ > +static ssize_t ras_event_counter_en_write(struct file *file, > + const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + u32 ret; > + u32 val; > + u32 enable; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + > + ret = kstrtou32_from_user(buf, count, 0, &enable); > + if (ret) > + return ret; > + > + set_event_number(file); > + > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + > + RAS_DES_EVENT_COUNTER_CTRL_REG); > + if (enable) > + val |= PER_EVENT_ON; > + else > + val |= PER_EVENT_OFF; > + > + dw_pcie_writel_dbi(pci, pci->ras_cap_offset + > + RAS_DES_EVENT_COUNTER_CTRL_REG, val); > + > + return count; > +} > + > +/* > + * ras_event_counter_lane_sel_write: Function to set lane number > + * > + * This function is invoked when the following command is made: > + * echo n > /sys/kernel/debug/dwc_pcie_plat/ras_des_counter//lane_select > + * Here n is the lane that we want to select for counter configuration > + */ > +static ssize_t ras_event_counter_lane_sel_write(struct file *file, > + const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + u32 ret; > + u32 val; > + u32 lane; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + > + ret = kstrtou32_from_user(buf, count, 0, &lane); > + if (ret) > + return ret; > + > + set_event_number(file); > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + > + RAS_DES_EVENT_COUNTER_CTRL_REG); > + val &= ~(LANE_SELECT_MASK << LANE_SELECT_SHIFT); > + val |= (lane << LANE_SELECT_SHIFT); > + dw_pcie_writel_dbi(pci, pci->ras_cap_offset + > + RAS_DES_EVENT_COUNTER_CTRL_REG, val); > + > + return count; > +} > + > +/* > + * ras_error_inj_read: Function to read number of errors left to be injected > + * > + * This function is invoked when the following command is made: > + * cat /sys/kernel/debug/dwc_pcie_plat/ras_des_error_inj/ > + * This returns the number of errors left to be injected which will > + * keep reducing as we make pcie transactions to inject error. Use "PCIe" in text. > + */ > +static ssize_t ras_error_inj_read(struct file *file, char __user *buf, > + size_t count, loff_t *ppos) > +{ > + u32 ret; > + u32 val, err_num, inj_num; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + > + err_num = get_error_inj_number(file); > + inj_num = (err_num & 0xFF); > + > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + ERR_INJ0_OFF + > + (0x4 * inj_num)); > + sprintf(debugfs_buf, "0x%x\n", (val & EINJ_COUNT_MASK)); > + ret = simple_read_from_buffer(buf, count, ppos, debugfs_buf, > + strlen(debugfs_buf)); > + > + return ret; > +} > + > +/* > + * ras_error_inj_write: Function to set number of errors to be injected > + * > + * This function is invoked when the following command is made: > + * echo n > /sys/kernel/debug/dwc_pcie_plat/ras_des_error_inj/ > + * Here n is the number of errors we want to inject > + */ > +static ssize_t ras_error_inj_write(struct file *file, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + u32 ret; > + u32 val, err_num, inj_num; > + u32 counter; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + > + if (count > DEBUGFS_BUF_MAX_SIZE) > + return -EINVAL; What is the point of this check? "debugfs_buf" isn't involved here. Same question for the similar test below. > + ret = kstrtou32_from_user(buf, count, 0, &counter); > + if (ret) > + return ret; > + > + err_num = get_error_inj_number(file); > + inj_num = (err_num & 0xFF); > + err_num = (err_num >> 8); > + > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + ERR_INJ0_OFF + > + (0x4 * inj_num)); > + val &= ~(EINJ_TYPE_MASK << EINJ_TYPE_SHIFT); > + val |= (err_num << EINJ_TYPE_SHIFT); > + val &= ~(EINJ_COUNT_MASK); > + val |= counter; > + dw_pcie_writel_dbi(pci, pci->ras_cap_offset + ERR_INJ0_OFF + > + (0x4 * inj_num), val); > + dw_pcie_writel_dbi(pci, pci->ras_cap_offset + > + ERR_INJ_ENABLE_REG, (0x1 << inj_num)); > + > + return count; > +} > + > +static ssize_t lane_detection_read(struct file *file, char __user *buf, > + size_t count, loff_t *ppos) > +{ > + u32 ret; > + u32 val; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + > + SD_STATUS_L1LANE_REG); > + val = (val >> LANE_DETECT_SHIFT) & LANE_DETECT_MASK; > + sprintf(debugfs_buf, "0x%x\n", val); > + > + ret = simple_read_from_buffer(buf, count, ppos, debugfs_buf, > + strlen(debugfs_buf)); > + > + return ret; > +} > + > +static ssize_t rx_valid_read(struct file *file, char __user *buf, > + size_t count, loff_t *ppos) > +{ > + u32 ret; > + u32 val; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + > + SD_STATUS_L1LANE_REG); > + val = (val >> PIPE_RXVALID_SHIFT) & PIPE_RXVALID_MASK; > + sprintf(debugfs_buf, "0x%x\n", val); > + > + ret = simple_read_from_buffer(buf, count, ppos, debugfs_buf, > + strlen(debugfs_buf)); > + > + return ret; > +} > + > +static ssize_t lane_selection_write(struct file *file, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + u32 ret; > + u32 val; > + u32 lane; > + struct dw_pcie *pci = (struct dw_pcie *) file->private_data; > + > + if (count > DEBUGFS_BUF_MAX_SIZE) > + return -EINVAL; > + > + ret = kstrtou32_from_user(buf, count, 0, &lane); > + if (ret) > + return ret; > + > + val = dw_pcie_readl_dbi(pci, pci->ras_cap_offset + > + SD_STATUS_L1LANE_REG); > + val &= ~(LANE_SELECT_MASK); Unnecessary parentheses. If needed, they should be in the LANE_SELECT_MASK definition. > + val |= lane; > + dw_pcie_writel_dbi(pci, pci->ras_cap_offset + > + SD_STATUS_L1LANE_REG, val); > + > + return count; > +} > + > +static const struct file_operations lane_detection_fops = { > + .open = open, > + .read = lane_detection_read, > + .write = lane_selection_write > +}; > + > +static const struct file_operations rx_valid_fops = { > + .open = open, > + .read = rx_valid_read, > + .write = lane_selection_write > +}; > + > +static const struct file_operations cnt_en_ops = { > + .read = ras_event_counter_en_read, > + .write = ras_event_counter_en_write, > + .open = simple_open, > +}; > + > +static const struct file_operations lane_sel_ops = { > + .read = ras_event_counter_lane_sel_read, > + .write = ras_event_counter_lane_sel_write, > + .open = simple_open, > +}; > + > +static const struct file_operations cnt_val_ops = { > + .read = ras_event_counter_value_read, > + .open = simple_open, > +}; > + > +static const struct file_operations inj_ops = { > + .read = ras_error_inj_read, > + .write = ras_error_inj_write, > + .open = simple_open, > +}; > + > +int create_debugfs_files(struct dw_pcie *pci) > +{ > + int ret = 0; > + char dirname[32]; > + struct device *dev; > + Remove spurious blank line above. > + struct dentry *ras_des_debug_regs; > + struct dentry *ras_des_error_inj; > + struct dentry *ras_des_event_counter; > + struct dentry *lane_detection; > + struct dentry *rx_valid; > + > + if (!pci) { > + pr_err("pcie struct is NULL\n"); > + return -ENODEV; > + } > + > + dev = pci->dev; > + sprintf(dirname, "pcie_dwc_%s", dev_name(dev)); scnprintf() to prevent buffer overflow. > + pci->ras_cap_offset = dw_pcie_find_vsec_capability(pci, > + DW_PCIE_RAS_CAP_ID); > + if (!pci->ras_cap_offset) { > + pr_err("No RAS capability available\n"); Use dev_err() here and below to connect the message with the device. > + return -ENODEV; > + } > + > + /* Create main directory for each platform driver */ > + dir = debugfs_create_dir(dirname, NULL); > + if (dir == NULL) { "if (!dir)" is typical style for NULL pointer checking. > + pr_err("error creating directory: %s\n", dirname); > + return -ENODEV; > + } > + > + /* Create sub dirs for Debug, Error injection, Statistics */ > + ras_des_debug_regs = debugfs_create_dir("ras_des_debug_regs", dir); > + if (ras_des_debug_regs == NULL) { > + pr_err("error creating directory: %s\n", dirname); > + ret = -ENODEV; > + goto remove_debug_file; > + } > + > + ras_des_error_inj = debugfs_create_dir("ras_des_error_inj", dir); > + if (ras_des_error_inj == NULL) { > + pr_err("error creating directory: %s\n", dirname); > + ret = -ENODEV; > + goto remove_debug_file; > + } > + > + ras_des_event_counter = debugfs_create_dir("ras_des_counter", dir); > + if (ras_des_event_counter == NULL) { > + pr_err("error creating directory: %s\n", dirname); > + ret = -ENODEV; > + goto remove_debug_file; > + } > + > + /* Create debugfs files for Debug subdirectory */ > + lane_detection = debugfs_create_file("lane_detection", 0644, > + ras_des_debug_regs, pci, > + &lane_detection_fops); > + > + rx_valid = debugfs_create_file("rx_valid", 0644, > + ras_des_debug_regs, pci, > + &lane_detection_fops); > + > + /* Create debugfs files for Error injection sub dir */ > + CREATE_RAS_ERROR_INJECTION_DEBUGFS(tx_ecrc); > + CREATE_RAS_ERROR_INJECTION_DEBUGFS(rx_ecrc); > + CREATE_RAS_ERROR_INJECTION_DEBUGFS(tx_lcrc); > + CREATE_RAS_ERROR_INJECTION_DEBUGFS(rx_lcrc); > + > + /* Create debugfs files for Statistical counter sub dir */ > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(ebuf_overflow); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(ebuf_underrun); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(decode_error); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(receiver_error); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(framing_error); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(lcrc_error); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(ecrc_error); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(unsupp_req_error); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(cmpltr_abort_error); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(cmpltn_timeout_error); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(tx_l0s_entry); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(rx_l0s_entry); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(l1_entry); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(l1_1_entry); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(l1_2_entry); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(l2_entry); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(speed_change); > + CREATE_RAS_EVENT_COUNTER_DEBUGFS(width_chage); > + > + return ret; > + > +remove_debug_file: > + remove_debugfs_files(); > + return ret; > +} > + > +void remove_debugfs_files(void) > +{ > + debugfs_remove_recursive(dir); > +} > diff --git a/drivers/pci/controller/dwc/pcie-designware-debugfs.h b/drivers/pci/controller/dwc/pcie-designware-debugfs.h This new file is only included from one place. Why not just put the contents there? > new file mode 100644 > index 000000000000..3dc3cf696a04 > --- /dev/null > +++ b/drivers/pci/controller/dwc/pcie-designware-debugfs.h > @@ -0,0 +1,133 @@ > +/* SPDX-License-Identifier: GPL-2.0 */ > +/* > + * Synopsys DesignWare PCIe controller debugfs driver > + * > + * Copyright (C) 2021 Samsung Electronics Co., Ltd. > + * http://www.samsung.com > + * > + * Author: Shradha Todi > + */ > + > +#ifndef _PCIE_DESIGNWARE_DEBUGFS_H > +#define _PCIE_DESIGNWARE_DEBUGFS_H > + > +#include "pcie-designware.h" > + > +#define RAS_DES_EVENT_COUNTER_CTRL_REG 0x8 > +#define RAS_DES_EVENT_COUNTER_DATA_REG 0xC > +#define SD_STATUS_L1LANE_REG 0xB0 > +#define ERR_INJ_ENABLE_REG 0x30 > +#define ERR_INJ0_OFF 0x34 > + > +#define LANE_DETECT_SHIFT 17 > +#define LANE_DETECT_MASK 0x1 > +#define PIPE_RXVALID_SHIFT 18 > +#define PIPE_RXVALID_MASK 0x1 > + > +#define LANE_SELECT_SHIFT 8 > +#define LANE_SELECT_MASK 0xF > +#define EVENT_COUNTER_STATUS_SHIFT 7 > +#define EVENT_COUNTER_STATUS_MASK 0x1 > +#define EVENT_COUNTER_ENABLE (0x7 << 2) > +#define PER_EVENT_OFF (0x1 << 2) > +#define PER_EVENT_ON (0x3 << 2) > + > +#define EINJ_COUNT_MASK 0xFF > +#define EINJ_TYPE_MASK 0xFFFFFF > +#define EINJ_TYPE_SHIFT 8 > + > +enum event_numbers { > + ebuf_overflow = 0x0, > + ebuf_underrun = 0x1, > + decode_error = 0x2, > + sync_header_error = 0x5, > + receiver_error = 0x106, > + framing_error = 0x109, > + lcrc_error = 0x201, > + ecrc_error = 0x302, > + unsupp_req_error = 0x303, > + cmpltr_abort_error = 0x304, > + cmpltn_timeout_error = 0x305, > + tx_l0s_entry = 0x502, > + rx_l0s_entry = 0x503, > + l1_entry = 0x505, > + l1_1_entry = 0x507, > + l1_2_entry = 0x508, > + l2_entry = 0x50B, > + speed_change = 0x50C, > + width_chage = 0x50D, > +}; > + > +/* > + * struct event_counters: Struct to store event number > + * > + * @name: name of the event counter > + * eg: ecrc_err count, l1 entry count > + * @event_num: Event number and group number > + * [16:8]: Group number > + * [7:0]: Event number > + */ > +struct event_counters { > + const char *name; > + u32 event_num; > +}; > + > +enum error_inj_code { > + tx_lcrc = 0x000, > + tx_ecrc = 0x300, > + rx_lcrc = 0x800, > + rx_ecrc = 0xB00, > +}; > + > +/* > + * struct error_injectionss: Struct to store error numbers s/error_injectionss/error_injections/ > + * > + * @name: name of the error to be injected > + * eg: ecrc_err, lcrc_err > + * @event_num: Error number and group number > + * [31:8]: Error type. This should be same as bits [31:8] > + * in the EINJn_REG where n is group number > + * [7:0]: Error injection group > + * 0 - CRC > + * 1 - seq num > + * 2 - DLLP error > + * 3 - symbol error > + * 4 - FC error > + */ > +struct error_injections { > + const char *name; > + u32 type_of_err; > +}; > + > +#define CREATE_RAS_EVENT_COUNTER_DEBUGFS(name) \ > +do { \ > + sub_dir = debugfs_create_dir(#name, ras_des_event_counter); \ > + debugfs_create_file("counter_enable", 0644, sub_dir, pci, \ > + &cnt_en_ops); \ > + debugfs_create_file("lane_select", 0644, sub_dir, pci, \ > + &lane_sel_ops); \ > + debugfs_create_file("counter_value", 0444, sub_dir, pci, \ > + &cnt_val_ops); \ > +} while (0) > + > +#define CREATE_RAS_ERROR_INJECTION_DEBUGFS(name) \ > + debugfs_create_file(#name, 0644, ras_des_error_inj, pci, \ > + &inj_ops); > + > +#ifdef CONFIG_PCIE_DW_DEBUGFS > +int create_debugfs_files(struct dw_pcie *pci); > +void remove_debugfs_files(void); > +#else > +int create_debugfs_files(struct dw_pcie *pci) > +{ > + /* No OP */ > + return 0; > +} > + > +void remove_debugfs_files(void) > +{ > + /* No OP */ > +} > +#endif > + > +#endif > diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/controller/dwc/pcie-designware.h > index 307525aaa063..031fdafe0a3e 100644 > --- a/drivers/pci/controller/dwc/pcie-designware.h > +++ b/drivers/pci/controller/dwc/pcie-designware.h > @@ -278,6 +278,7 @@ struct dw_pcie { > u8 n_fts[2]; > bool iatu_unroll_enabled: 1; > bool io_cfg_atu_shared: 1; > + u32 ras_cap_offset; u16 should be sufficient, since that's what dw_pcie_find_vsec_capability() returns. I would just call it "ras" with a comment here about it being a "VSEC RAS capability". But that's just a personal preference. > }; > > #define to_dw_pcie_from_pp(port) container_of((port), struct dw_pcie, pp) > -- > 2.17.1 >