On Fri, Feb 14, 2025 at 04:20:05PM +0530, Shradha Todi wrote: > Add support to provide silicon debug interface to userspace. This set > of debug registers are part of the RASDES feature present in DesignWare > PCIe controllers. > > Signed-off-by: Shradha Todi <shradha.t@xxxxxxxxxxx> > --- > Documentation/ABI/testing/debugfs-dwc-pcie | 13 ++ > drivers/pci/controller/dwc/Kconfig | 10 + > drivers/pci/controller/dwc/Makefile | 1 + > .../controller/dwc/pcie-designware-debugfs.c | 207 ++++++++++++++++++ > .../pci/controller/dwc/pcie-designware-ep.c | 5 + > .../pci/controller/dwc/pcie-designware-host.c | 6 + > drivers/pci/controller/dwc/pcie-designware.h | 20 ++ > 7 files changed, 262 insertions(+) > create mode 100644 Documentation/ABI/testing/debugfs-dwc-pcie > create mode 100644 drivers/pci/controller/dwc/pcie-designware-debugfs.c > > diff --git a/Documentation/ABI/testing/debugfs-dwc-pcie b/Documentation/ABI/testing/debugfs-dwc-pcie > new file mode 100644 > index 000000000000..e8ed34e988ef > --- /dev/null > +++ b/Documentation/ABI/testing/debugfs-dwc-pcie > @@ -0,0 +1,13 @@ > +What: /sys/kernel/debug/dwc_pcie_<dev>/rasdes_debug/lane_detect > +Date: Feburary 2025 Please align these fields > +Contact: Shradha Todi <shradha.t@xxxxxxxxxxx> > +Description: (RW) Write the lane number to be checked for detection. Read > + will return whether PHY indicates receiver detection on the > + selected lane. The default selected lane is Lane0. > + > +What: /sys/kernel/debug/dwc_pcie_<dev>/rasdes_debug/rx_valid > +Date: Feburary 2025 > +Contact: Shradha Todi <shradha.t@xxxxxxxxxxx> > +Description: (RW) Write the lane number to be checked as valid or invalid. Read > + will return the status of PIPE RXVALID signal of the selected lane. > + The default selected lane is Lane0. > diff --git a/drivers/pci/controller/dwc/Kconfig b/drivers/pci/controller/dwc/Kconfig > index b6d6778b0698..48a10428a492 100644 > --- a/drivers/pci/controller/dwc/Kconfig > +++ b/drivers/pci/controller/dwc/Kconfig > @@ -6,6 +6,16 @@ menu "DesignWare-based PCIe controllers" > config PCIE_DW > bool > > +config PCIE_DW_DEBUGFS > + default y > + depends on DEBUG_FS > + depends on PCIE_DW_HOST || PCIE_DW_EP > + bool "DWC PCIe debugfs entries" > + help > + Enables debugfs entries for the DW PCIe Controller. These entries > + provide all debug features related to DW controller including the RAS > + DES features to help in debug, error injection and statistical counters. > + > config PCIE_DW_HOST > bool > select PCIE_DW > diff --git a/drivers/pci/controller/dwc/Makefile b/drivers/pci/controller/dwc/Makefile > index a8308d9ea986..54565eedc52c 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..fe799d36fa7f > --- /dev/null > +++ b/drivers/pci/controller/dwc/pcie-designware-debugfs.c > @@ -0,0 +1,207 @@ > +// SPDX-License-Identifier: GPL-2.0 > +/* > + * Synopsys DesignWare PCIe controller debugfs driver > + * > + * Copyright (C) 2025 Samsung Electronics Co., Ltd. > + * http://www.samsung.com > + * > + * Author: Shradha Todi <shradha.t@xxxxxxxxxxx> > + */ > + > +#include <linux/debugfs.h> > + > +#include "pcie-designware.h" > + > +#define SD_STATUS_L1LANE_REG 0xb0 > +#define PIPE_RXVALID BIT(18) > +#define PIPE_DETECT_LANE BIT(17) > +#define LANE_SELECT GENMASK(3, 0) > + > +#define DWC_DEBUGFS_BUF_MAX 128 > + > +struct dwc_pcie_vsec_id { > + u16 vendor_id; > + u16 vsec_id; > + u8 vsec_rev; > +}; > + > +/* > + * VSEC IDs are allocated by the vendor, so a given ID may mean different > + * things to different vendors. See PCIe r6.0, sec 7.9.5.2. > + */ > +static const struct dwc_pcie_vsec_id dwc_pcie_vsec_ids[] = { > + { .vendor_id = PCI_VENDOR_ID_ALIBABA, > + .vsec_id = 0x02, .vsec_rev = 0x4 }, > + { .vendor_id = PCI_VENDOR_ID_AMPERE, > + .vsec_id = 0x02, .vsec_rev = 0x4 }, > + { .vendor_id = PCI_VENDOR_ID_QCOM, > + .vsec_id = 0x02, .vsec_rev = 0x4 }, > + { .vendor_id = PCI_VENDOR_ID_SAMSUNG, > + .vsec_id = 0x02, .vsec_rev = 0x4 }, > + {} /* terminator */ This should go into the common include file as I proposed in my series: https://lore.kernel.org/linux-pci/20250218-pcie-qcom-ptm-v1-1-16d7e480d73e@xxxxxxxxxx/ > +}; > + > +/** > + * struct dwc_pcie_rasdes_info - Stores controller common information > + * @ras_cap_offset: RAS DES vendor specific extended capability offset > + * @reg_lock: Mutex used for RASDES shadow event registers If this is not used by all register accesses, please rename it as such. Like, reg_event_lock. > + * > + * Any parameter constant to all files of the debugfs hierarchy for a single controller > + * will be stored in this struct. It is allocated and assigned to controller specific > + * struct dw_pcie during initialization. > + */ > +struct dwc_pcie_rasdes_info { > + u32 ras_cap_offset; > + struct mutex reg_lock; > +}; > + > +static ssize_t lane_detect_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) > +{ > + struct dw_pcie *pci = file->private_data; > + struct dwc_pcie_rasdes_info *rinfo = pci->debugfs->rasdes_info; > + char debugfs_buf[DWC_DEBUGFS_BUF_MAX]; > + ssize_t off = 0; Not required. See below. > + u32 val; > + > + val = dw_pcie_readl_dbi(pci, rinfo->ras_cap_offset + SD_STATUS_L1LANE_REG); > + val = FIELD_GET(PIPE_DETECT_LANE, val); > + if (val) > + off += scnprintf(debugfs_buf, DWC_DEBUGFS_BUF_MAX - off, "Lane Detected\n"); I don't understand why you want to add 'off' which was initialized to 0. Also this just prints single string. > + else > + off += scnprintf(debugfs_buf, DWC_DEBUGFS_BUF_MAX - off, "Lane Undetected\n"); > + > + return simple_read_from_buffer(buf, count, ppos, debugfs_buf, off); > +} > + > +static ssize_t lane_detect_write(struct file *file, const char __user *buf, > + size_t count, loff_t *ppos) > +{ > + struct dw_pcie *pci = file->private_data; > + struct dwc_pcie_rasdes_info *rinfo = pci->debugfs->rasdes_info; > + u32 lane, val; > + > + val = kstrtou32_from_user(buf, count, 0, &lane); > + if (val) > + return val; > + > + val = dw_pcie_readl_dbi(pci, rinfo->ras_cap_offset + SD_STATUS_L1LANE_REG); > + val &= ~(LANE_SELECT); > + val |= FIELD_PREP(LANE_SELECT, lane); > + dw_pcie_writel_dbi(pci, rinfo->ras_cap_offset + SD_STATUS_L1LANE_REG, val); > + > + return count; > +} > + > +static ssize_t rx_valid_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) > +{ > + struct dw_pcie *pci = file->private_data; > + struct dwc_pcie_rasdes_info *rinfo = pci->debugfs->rasdes_info; > + char debugfs_buf[DWC_DEBUGFS_BUF_MAX]; > + ssize_t off = 0; > + u32 val; > + > + val = dw_pcie_readl_dbi(pci, rinfo->ras_cap_offset + SD_STATUS_L1LANE_REG); > + val = FIELD_GET(PIPE_RXVALID, val); > + if (val) > + off += scnprintf(debugfs_buf, DWC_DEBUGFS_BUF_MAX - off, "RX Valid\n"); Same here. > + else > + off += scnprintf(debugfs_buf, DWC_DEBUGFS_BUF_MAX - off, "RX Invalid\n"); > + > + return simple_read_from_buffer(buf, count, ppos, debugfs_buf, off); > +} > + > +static ssize_t rx_valid_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) > +{ > + return lane_detect_write(file, buf, count, ppos); > +} > + > +#define dwc_debugfs_create(name) \ > +debugfs_create_file(#name, 0644, rasdes_debug, pci, \ > + &dbg_ ## name ## _fops) > + > +#define DWC_DEBUGFS_FOPS(name) \ > +static const struct file_operations dbg_ ## name ## _fops = { \ > + .open = simple_open, \ > + .read = name ## _read, \ > + .write = name ## _write \ > +} > + > +DWC_DEBUGFS_FOPS(lane_detect); > +DWC_DEBUGFS_FOPS(rx_valid); > + > +static void dwc_pcie_rasdes_debugfs_deinit(struct dw_pcie *pci) > +{ > + struct dwc_pcie_rasdes_info *rinfo = pci->debugfs->rasdes_info; > + > + mutex_destroy(&rinfo->reg_lock); > +} > + > +static int dwc_pcie_rasdes_debugfs_init(struct dw_pcie *pci, struct dentry *dir) > +{ > + struct dentry *rasdes_debug; > + struct dwc_pcie_rasdes_info *rasdes_info; > + const struct dwc_pcie_vsec_id *vid; > + struct device *dev = pci->dev; > + int ras_cap; > + > + for (vid = dwc_pcie_vsec_ids; vid->vendor_id; vid++) { > + ras_cap = dw_pcie_find_vsec_capability(pci, vid->vendor_id, > + vid->vsec_id); > + if (ras_cap) > + break; > + } > + if (!ras_cap) { > + dev_dbg(dev, "no rasdes capability available\n"); > + return -ENODEV; > + } This will also go inside a new API, dw_pcie_find_rasdes_capability(pci). > + > + rasdes_info = devm_kzalloc(dev, sizeof(*rasdes_info), GFP_KERNEL); > + if (!rasdes_info) > + return -ENOMEM; > + > + /* Create subdirectories for Debug, Error injection, Statistics */ > + rasdes_debug = debugfs_create_dir("rasdes_debug", dir); _debug prefix is not needed since the directory itself belongs to debugfs. > + > + mutex_init(&rasdes_info->reg_lock); > + rasdes_info->ras_cap_offset = ras_cap; > + pci->debugfs->rasdes_info = rasdes_info; > + > + /* Create debugfs files for Debug subdirectory */ > + dwc_debugfs_create(lane_detect); > + dwc_debugfs_create(rx_valid); > + > + return 0; > +} > + > +void dwc_pcie_debugfs_deinit(struct dw_pcie *pci) > +{ > + dwc_pcie_rasdes_debugfs_deinit(pci); > + debugfs_remove_recursive(pci->debugfs->debug_dir); > +} > + > +int dwc_pcie_debugfs_init(struct dw_pcie *pci) > +{ > + char dirname[DWC_DEBUGFS_BUF_MAX]; > + struct device *dev = pci->dev; > + struct debugfs_info *debugfs; > + struct dentry *dir; > + int ret; > + > + /* Create main directory for each platform driver */ > + snprintf(dirname, DWC_DEBUGFS_BUF_MAX, "dwc_pcie_%s", dev_name(dev)); > + dir = debugfs_create_dir(dirname, NULL); > + if (IS_ERR(dir)) > + return PTR_ERR(dir); debugfs creation is not supposed to fail. So you should remove the error check. > + > + debugfs = devm_kzalloc(dev, sizeof(*debugfs), GFP_KERNEL); > + if (!debugfs) > + return -ENOMEM; > + > + debugfs->debug_dir = dir; > + pci->debugfs = debugfs; > + ret = dwc_pcie_rasdes_debugfs_init(pci, dir); > + if (ret) > + dev_dbg(dev, "rasdes debugfs init failed\n"); RASDES > + > + return 0; > +} > diff --git a/drivers/pci/controller/dwc/pcie-designware-ep.c b/drivers/pci/controller/dwc/pcie-designware-ep.c > index f3ac7d46a855..a87a714bb472 100644 > --- a/drivers/pci/controller/dwc/pcie-designware-ep.c > +++ b/drivers/pci/controller/dwc/pcie-designware-ep.c > @@ -642,6 +642,7 @@ void dw_pcie_ep_cleanup(struct dw_pcie_ep *ep) > { > struct dw_pcie *pci = to_dw_pcie_from_ep(ep); > > + dwc_pcie_debugfs_deinit(pci); > dw_pcie_edma_remove(pci); > } > EXPORT_SYMBOL_GPL(dw_pcie_ep_cleanup); > @@ -813,6 +814,10 @@ int dw_pcie_ep_init_registers(struct dw_pcie_ep *ep) > > dw_pcie_ep_init_non_sticky_registers(pci); > > + ret = dwc_pcie_debugfs_init(pci); > + if (ret) > + goto err_remove_edma; > + > return 0; > > err_remove_edma: > diff --git a/drivers/pci/controller/dwc/pcie-designware-host.c b/drivers/pci/controller/dwc/pcie-designware-host.c > index d2291c3ceb8b..6b03ef7fd014 100644 > --- a/drivers/pci/controller/dwc/pcie-designware-host.c > +++ b/drivers/pci/controller/dwc/pcie-designware-host.c > @@ -524,6 +524,10 @@ int dw_pcie_host_init(struct dw_pcie_rp *pp) > if (ret) > goto err_remove_edma; > > + ret = dwc_pcie_debugfs_init(pci); > + if (ret) > + goto err_remove_edma; > + Why can't you move it to the end of the function? > if (!dw_pcie_link_up(pci)) { > ret = dw_pcie_start_link(pci); > if (ret) > @@ -571,6 +575,8 @@ void dw_pcie_host_deinit(struct dw_pcie_rp *pp) > > dw_pcie_stop_link(pci); > > + dwc_pcie_debugfs_deinit(pci); > + This should be moved to the start of the function. - Mani -- மணிவண்ணன் சதாசிவம்
