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If a storage endpoint is present downstream, the dump is printed directly via dev_err() so it is visible in dmesg immediately, since a devcoredump read from userspace could otherwise race with a storage failure. Otherwise, the buffer is handed to the devcoredump framework so it can be collected from /sys/class/devcoredump/ for offline analysis. To keep the dump readable given the number of registers involved, entries are packed as "offset: value" pairs, QCOM_PCIE_DUMP_REGS_PER_LINE (4) per dmesg line, with a section header ("DBI registers:", "PARF registers:", "MHI registers:") identifying each register group. Also expose the same dump on demand via a new "regdump" debugfs file under the existing per-controller debugfs directory, so the register state can be inspected without needing an actual Link Down event. Signed-off-by: Krishna Chaitanya Chundru --- drivers/pci/controller/dwc/pcie-designware.h | 6 + drivers/pci/controller/dwc/pcie-qcom.c | 328 +++++++++++++++++++++++= ++++ include/uapi/linux/pci_regs.h | 2 + 3 files changed, 336 insertions(+) diff --git a/drivers/pci/controller/dwc/pcie-designware.h b/drivers/pci/con= troller/dwc/pcie-designware.h index 1d2139474157..14d6d441c1a5 100644 --- a/drivers/pci/controller/dwc/pcie-designware.h +++ b/drivers/pci/controller/dwc/pcie-designware.h @@ -290,6 +290,12 @@ =20 #define PCIE_RAS_DES_EVENT_COUNTER_DATA 0xc =20 +/* SD-EQ (Gen5 32 GT/s per-lane pre/post cursor equalization) registers */ +#define PCIE_RAS_DES_SD_EQ_CONTROL1 0xd0 +#define PCIE_RAS_DES_SD_EQ_CONTROL1_LANE_SEL GENMASK(3, 0) +#define PCIE_RAS_DES_SD_EQ_STATUS2 0xe4 +#define PCIE_RAS_DES_SD_EQ_STATUS3 0xe8 + /* PTM register definitions */ #define PTM_RES_REQ_CTRL 0x8 #define PTM_RES_CCONTEXT_VALID BIT(0) diff --git a/drivers/pci/controller/dwc/pcie-qcom.c b/drivers/pci/controlle= r/dwc/pcie-qcom.c index b58a607b713f..a9b1d8327c72 100644 --- a/drivers/pci/controller/dwc/pcie-qcom.c +++ b/drivers/pci/controller/dwc/pcie-qcom.c @@ -12,6 +12,7 @@ #include #include #include +#include #include #include #include @@ -44,6 +45,8 @@ /* PARF registers */ #define PARF_SYS_CTRL 0x00 #define PARF_PM_CTRL 0x20 +#define PARF_PM_STTS 0x24 +#define PARF_PM_STTS_1 0x28 #define PARF_PCS_DEEMPH 0x34 #define PARF_PCS_SWING 0x38 #define PARF_PHY_CTRL 0x40 @@ -62,11 +65,17 @@ #define PARF_STATUS 0x230 #define PARF_SID_OFFSET 0x234 #define PARF_BDF_TRANSLATE_CFG 0x24c +#define PARF_CLKREQ_OVERRIDE 0x2b0 #define PARF_DBI_BASE_ADDR_V2 0x350 #define PARF_DBI_BASE_ADDR_V2_HI 0x354 #define PARF_SLV_ADDR_SPACE_SIZE_V2 0x358 #define PARF_SLV_ADDR_SPACE_SIZE_V2_HI 0x35c #define PARF_NO_SNOOP_OVERRIDE 0x3d4 +#define PARF_CORE_ERRORS 0x3c0 +#define PARF_L1SS_SLEEP_MODE_HANDLER_STATUS 0x4d0 +#define PARF_L1SS_SLEEP_MODE_HANDLER_CFG 0x4d4 +#define PARF_INT_ALL_2_STATUS 0x500 +#define PARF_LINK_DOWN_AXI_ECAM_BLOCK_STATUS 0x630 #define PARF_ATU_BASE_ADDR 0x634 #define PARF_ATU_BASE_ADDR_HI 0x638 #define PARF_DEVICE_TYPE 0x1000 @@ -83,8 +92,12 @@ =20 /* MHI registers */ #define PARF_DEBUG_CNT_PM_LINKST_IN_L2 0xc04 +#define PARF_DEBUG_CNT_PM_LINKST_IN_L1SUB 0xc08 #define PARF_DEBUG_CNT_PM_LINKST_IN_L1 0xc0c #define PARF_DEBUG_CNT_PM_LINKST_IN_L0S 0xc10 +#define PARF_DEBUG_CNT_AUX_CLK_APP_REQ_EXIT_L1 0xc14 +#define PARF_DEBUG_CNT_AUX_CLK_APP_READY_ENTER_L23 0xc18 +#define PARF_DEBUG_CNT_AUX_CLK_APP_READY_ENTER_L1 0xc1c #define PARF_DEBUG_CNT_AUX_CLK_IN_L1SUB_L1 0xc84 #define PARF_DEBUG_CNT_AUX_CLK_IN_L1SUB_L2 0xc88 =20 @@ -188,11 +201,48 @@ #define PERST_DELAY_US 1000 #define FLUSH_TIMEOUT_US 100 =20 +/* Dump buffer size for the link-down register dump */ +#define QCOM_PCIE_DUMP_BUF_SIZE SZ_8K + #define QCOM_PCIE_CRC8_POLYNOMIAL (BIT(2) | BIT(1) | BIT(0)) =20 #define QCOM_PCIE_LINK_SPEED_TO_BW(speed) \ Mbps_to_icc(PCIE_SPEED2MBS_ENC(pcie_get_link_speed(speed))) =20 +#define QCOM_PCIE_DUMP_REGS_PER_LINE 4 + +static const u32 qcom_pcie_parf_dump_regs[] =3D { + PARF_LTSSM, + PARF_INT_ALL_STATUS, + PARF_SYS_CTRL, +}; + +static const u32 qcom_pcie_ext_parf_dump_regs[] =3D { + PARF_PM_STTS, + PARF_PM_STTS_1, + PARF_INT_ALL_STATUS, + PARF_INT_ALL_2_STATUS, + PARF_CLKREQ_OVERRIDE, + PARF_L1SS_SLEEP_MODE_HANDLER_STATUS, + PARF_L1SS_SLEEP_MODE_HANDLER_CFG, + PARF_CORE_ERRORS, + PARF_LINK_DOWN_AXI_ECAM_BLOCK_STATUS, + PARF_STATUS, + PARF_SYS_CTRL, +}; + +static const u32 qcom_pcie_mhi_dump_regs[] =3D { + PARF_DEBUG_CNT_PM_LINKST_IN_L2, + PARF_DEBUG_CNT_PM_LINKST_IN_L1SUB, + PARF_DEBUG_CNT_PM_LINKST_IN_L1, + PARF_DEBUG_CNT_PM_LINKST_IN_L0S, + PARF_DEBUG_CNT_AUX_CLK_APP_REQ_EXIT_L1, + PARF_DEBUG_CNT_AUX_CLK_APP_READY_ENTER_L23, + PARF_DEBUG_CNT_AUX_CLK_APP_READY_ENTER_L1, + PARF_DEBUG_CNT_AUX_CLK_IN_L1SUB_L1, + PARF_DEBUG_CNT_AUX_CLK_IN_L1SUB_L2, +}; + struct qcom_pcie_resources_1_0_0 { struct clk_bulk_data *clks; int num_clks; @@ -275,12 +325,15 @@ struct qcom_pcie_ops { * @override_no_snoop: Override NO_SNOOP attribute in TLP to enable cache * snooping * @firmware_managed: Set if the Root Complex is firmware managed + * @has_ext_parf_regs: Set if the PARF block implements the extended + * register set used by qcom_pcie_dump_regs(). */ struct qcom_pcie_cfg { const struct qcom_pcie_ops *ops; bool override_no_snoop; bool firmware_managed; bool no_l0s; + bool has_ext_parf_regs; }; =20 struct qcom_pcie_perst { @@ -1597,12 +1650,14 @@ static const struct qcom_pcie_cfg cfg_1_0_0 =3D { =20 static const struct qcom_pcie_cfg cfg_1_9_0 =3D { .ops =3D &ops_1_9_0, + .has_ext_parf_regs =3D true, }; =20 static const struct qcom_pcie_cfg cfg_1_34_0 =3D { .ops =3D &ops_1_9_0, .override_no_snoop =3D true, .no_l0s =3D true, + .has_ext_parf_regs =3D true, }; =20 static const struct qcom_pcie_cfg cfg_2_1_0 =3D { @@ -1624,6 +1679,7 @@ static const struct qcom_pcie_cfg cfg_2_4_0 =3D { =20 static const struct qcom_pcie_cfg cfg_2_7_0 =3D { .ops =3D &ops_2_7_0, + .has_ext_parf_regs =3D true, }; =20 static const struct qcom_pcie_cfg cfg_2_9_0 =3D { @@ -1633,6 +1689,7 @@ static const struct qcom_pcie_cfg cfg_2_9_0 =3D { static const struct qcom_pcie_cfg cfg_sc8280xp =3D { .ops =3D &ops_1_21_0, .no_l0s =3D true, + .has_ext_parf_regs =3D true, }; =20 static const struct qcom_pcie_cfg cfg_fw_managed =3D { @@ -1760,6 +1817,274 @@ static int qcom_pcie_set_max_opp(struct device *dev) return ret; } =20 +static int qcom_pcie_has_storage_ep_cb(struct pci_dev *pdev, void *data) +{ + bool *found =3D data; + + if (pdev->class >> 16 =3D=3D PCI_BASE_CLASS_STORAGE) { + *found =3D true; + return 1; + } + + return 0; +} + +static bool qcom_pcie_has_storage_ep(struct qcom_pcie *pcie) +{ + struct dw_pcie_rp *pp =3D &pcie->pci->pp; + bool found =3D false; + + pci_walk_bus(pp->bridge->bus, qcom_pcie_has_storage_ep_cb, &found); + + return found; +} + +/* + * qcom_pcie_dump_advance_col - advance @col and append a separator to @bu= f. + * + * @col tracks the current column within the active section and must be + * reset to 0 by the caller at the start of each new section; a newline is + * emitted every QCOM_PCIE_DUMP_REGS_PER_LINE entries to keep the dump + * compact in dmesg. + */ +static size_t qcom_pcie_dump_advance_col(char *buf, size_t buf_size, int *= col) +{ + *col +=3D 1; + + return scnprintf(buf, buf_size, + (*col % QCOM_PCIE_DUMP_REGS_PER_LINE) ? " " : "\n"); +} + +static size_t qcom_pcie_dump_reg_val(char *buf, size_t buf_size, int *col, + u32 offset, u32 val) +{ + size_t len; + + len =3D scnprintf(buf, buf_size, "0x%03x: 0x%08x", offset, val); + len +=3D qcom_pcie_dump_advance_col(buf + len, buf_size - len, col); + + return len; +} + +/* Same as qcom_pcie_dump_reg_val(), but tags the entry with a lane number + * since the RAS-DES SD-EQ status registers are read once per lane at a + * fixed offset, so the offset alone can't tell entries apart. + */ +static size_t qcom_pcie_dump_lane_reg_val(char *buf, size_t buf_size, int = *col, + int lane, u32 offset, u32 val) +{ + size_t len; + + len =3D scnprintf(buf, buf_size, "L%d/0x%03x: 0x%08x", lane, offset, val); + len +=3D qcom_pcie_dump_advance_col(buf + len, buf_size - len, col); + + return len; +} + +static size_t qcom_pcie_dump_reg_table(void __iomem *base, const u32 *regs, + int nregs, char *buf, size_t buf_size) +{ + size_t len =3D 0; + int col =3D 0; + int i; + + for (i =3D 0; i < nregs; i++) + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + regs[i], readl_relaxed(base + regs[i])); + + if (col % QCOM_PCIE_DUMP_REGS_PER_LINE) + len +=3D scnprintf(buf + len, buf_size - len, "\n"); + + return len; +} + +/* + * qcom_pcie_fill_dump_buf - fill @buf with key PCIe register values captu= red + * at Link Down time. + * + * Returns the number of bytes written into @buf. + */ +static size_t qcom_pcie_fill_dump_buf(struct qcom_pcie *pcie, char *buf, + size_t buf_size) +{ + struct dw_pcie *pci =3D pcie->pci; + u16 exp_cap, aer_cap, l1ss_cap, secpci_cap, pl16gt_cap, pl32gt_cap; + size_t len =3D 0; + int col =3D 0; + u32 val; + + len +=3D scnprintf(buf + len, buf_size - len, "DBI registers:\n"); + + exp_cap =3D dw_pcie_find_capability(pci, PCI_CAP_ID_EXP); + if (exp_cap) { + val =3D dw_pcie_readl_dbi(pci, exp_cap + PCI_EXP_LNKCAP); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + exp_cap + PCI_EXP_LNKCAP, val); + + val =3D dw_pcie_readl_dbi(pci, exp_cap + PCI_EXP_LNKCTL); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + exp_cap + PCI_EXP_LNKCTL, val); + + val =3D dw_pcie_readl_dbi(pci, exp_cap + PCI_EXP_LNKCTL2); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + exp_cap + PCI_EXP_LNKCTL2, val); + } + + aer_cap =3D dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_ERR); + if (aer_cap) { + val =3D dw_pcie_readl_dbi(pci, aer_cap + PCI_ERR_UNCOR_STATUS); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + aer_cap + PCI_ERR_UNCOR_STATUS, val); + + val =3D dw_pcie_readl_dbi(pci, aer_cap + PCI_ERR_COR_STATUS); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + aer_cap + PCI_ERR_COR_STATUS, val); + } + + l1ss_cap =3D dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_L1SS); + if (l1ss_cap) { + val =3D dw_pcie_readl_dbi(pci, l1ss_cap + PCI_L1SS_CTL1); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + l1ss_cap + PCI_L1SS_CTL1, val); + } + + secpci_cap =3D dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_SECPCI); + if (secpci_cap) { + val =3D dw_pcie_readl_dbi(pci, secpci_cap + PCI_SECPCI_LE_CTRL); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + secpci_cap + PCI_SECPCI_LE_CTRL, val); + + val =3D dw_pcie_readl_dbi(pci, secpci_cap + PCI_SECPCI_LE_CTRL + 4); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + secpci_cap + PCI_SECPCI_LE_CTRL + 4, val); + } + + pl16gt_cap =3D dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_PL_16GT); + if (pl16gt_cap) { + val =3D dw_pcie_readl_dbi(pci, pl16gt_cap + PCI_PL_16GT_LE_CTRL); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + pl16gt_cap + PCI_PL_16GT_LE_CTRL, val); + + val =3D dw_pcie_readl_dbi(pci, pl16gt_cap + PCI_PL_16GT_STATUS); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + pl16gt_cap + PCI_PL_16GT_STATUS, val); + } + + pl32gt_cap =3D dw_pcie_find_ext_capability(pci, PCI_EXT_CAP_ID_PL_32GT); + if (pl32gt_cap) { + val =3D dw_pcie_readl_dbi(pci, pl32gt_cap + PCI_PL_32GT_LE_CTRL); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + pl32gt_cap + PCI_PL_32GT_LE_CTRL, val); + + val =3D dw_pcie_readl_dbi(pci, pl32gt_cap + PCI_PL_32GT_STATUS); + len +=3D qcom_pcie_dump_reg_val(buf + len, buf_size - len, &col, + pl32gt_cap + PCI_PL_32GT_STATUS, val); + } + + /* + * Gen5 (32 GT/s) local/remote pre/post cursor status, read through the + * SD-EQ registers inside the DWC RAS-DES vendor-specific extended + * capability. For each lane, write the lane selector into + * PCIE_RAS_DES_SD_EQ_CONTROL1 then read back + * PCIE_RAS_DES_SD_EQ_STATUS2/3, which carry the local/remote pre/post + * cursor values. + */ + if (pcie_get_link_speed(pci->max_link_speed) =3D=3D PCIE_SPEED_32_0GT) { + u16 rasdes_cap =3D dw_pcie_find_rasdes_capability(pci); + + if (rasdes_cap) { + int num_lanes =3D dw_pcie_link_get_max_link_width(pci); + int lane; + + for (lane =3D 0; lane < num_lanes; lane++) { + dw_pcie_writel_dbi(pci, + rasdes_cap + PCIE_RAS_DES_SD_EQ_CONTROL1, + lane & PCIE_RAS_DES_SD_EQ_CONTROL1_LANE_SEL); + + val =3D dw_pcie_readl_dbi(pci, + rasdes_cap + PCIE_RAS_DES_SD_EQ_STATUS2); + len +=3D qcom_pcie_dump_lane_reg_val(buf + len, buf_size - len, &col, + lane, + rasdes_cap + PCIE_RAS_DES_SD_EQ_STATUS2, + val); + + val =3D dw_pcie_readl_dbi(pci, + rasdes_cap + PCIE_RAS_DES_SD_EQ_STATUS3); + len +=3D qcom_pcie_dump_lane_reg_val(buf + len, buf_size - len, &col, + lane, + rasdes_cap + PCIE_RAS_DES_SD_EQ_STATUS3, + val); + } + } + } + + if (col % QCOM_PCIE_DUMP_REGS_PER_LINE) + len +=3D scnprintf(buf + len, buf_size - len, "\n"); + + len +=3D scnprintf(buf + len, buf_size - len, "\nPARF registers:\n"); + len +=3D qcom_pcie_dump_reg_table(pcie->parf, qcom_pcie_parf_dump_regs, + ARRAY_SIZE(qcom_pcie_parf_dump_regs), + buf + len, buf_size - len); + + if (!pcie->mhi) + return len; + + len +=3D scnprintf(buf + len, buf_size - len, "\nMHI registers:\n"); + len +=3D qcom_pcie_dump_reg_table(pcie->mhi, qcom_pcie_mhi_dump_regs, + ARRAY_SIZE(qcom_pcie_mhi_dump_regs), + buf + len, buf_size - len); + + return len; +} + +/* + * qcom_pcie_dump_regs - capture a PCIe register dump on Link Down. + * + * If a storage endpoint is present downstream, print the dump directly to + * dmesg via dev_err() so it is immediately visible even if userspace is n= ot + * available to read a devcoredump after a storage failure. Otherwise hand + * the buffer to the devcoredump framework so it is accessible under + * /sys/class/devcoredump/ for offline analysis. + */ +static void qcom_pcie_dump_regs(struct qcom_pcie *pcie) +{ + struct device *dev =3D pcie->pci->dev; + bool storage_ep =3D qcom_pcie_has_storage_ep(pcie); + char *buf; + size_t len; + + buf =3D vmalloc(QCOM_PCIE_DUMP_BUF_SIZE); + if (!buf) + return; + + len =3D qcom_pcie_fill_dump_buf(pcie, buf, QCOM_PCIE_DUMP_BUF_SIZE); + + if (storage_ep) { + dev_err(dev, "PCIe Link Down register dump:\n%s", buf); + vfree(buf); + } else { + dev_coredumpv(dev, buf, len, GFP_KERNEL); + } +} + +static int qcom_pcie_regdump_show(struct seq_file *s, void *data) +{ + struct qcom_pcie *pcie =3D (struct qcom_pcie *)dev_get_drvdata(s->private= ); + char *buf; + size_t len; + + buf =3D vmalloc(QCOM_PCIE_DUMP_BUF_SIZE); + if (!buf) + return -ENOMEM; + + len =3D qcom_pcie_fill_dump_buf(pcie, buf, QCOM_PCIE_DUMP_BUF_SIZE); + seq_write(s, buf, len); + + vfree(buf); + + return 0; +} + /* * Qcom PCIe controllers only support one Root Port per controller instanc= e. So * this function ignores the 'pci_dev' associated with the Root Port and j= ust @@ -1864,6 +2189,8 @@ static void qcom_pcie_init_debugfs(struct qcom_pcie *= pcie) pcie->debugfs =3D debugfs_create_dir(name, NULL); debugfs_create_devm_seqfile(dev, "link_transition_count", pcie->debugfs, qcom_pcie_link_transition_count); + debugfs_create_devm_seqfile(dev, "regdump", pcie->debugfs, + qcom_pcie_regdump_show); } =20 static irqreturn_t qcom_pcie_global_irq_thread(int irq, void *data) @@ -1878,6 +2205,7 @@ static irqreturn_t qcom_pcie_global_irq_thread(int ir= q, void *data) =20 if (test_and_clear_bit(INT_ALL_LINK_DOWN, &status)) { dev_dbg(dev, "Received Link down event\n"); + qcom_pcie_dump_regs(pcie); for_each_pci_bridge(port, pp->bridge->bus) { if (pci_pcie_type(port) =3D=3D PCI_EXP_TYPE_ROOT_PORT) pci_host_handle_link_down(port); diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h index facaa324bd86..0e82d89e747a 100644 --- a/include/uapi/linux/pci_regs.h +++ b/include/uapi/linux/pci_regs.h @@ -1176,12 +1176,14 @@ #define PCI_SECPCI_LE_CTRL 0x0c /* Lane Equalization Control Register */ =20 /* Physical Layer 16.0 GT/s */ +#define PCI_PL_16GT_STATUS 0x0c /* 16.0 GT/s Status Register */ #define PCI_PL_16GT_LE_CTRL 0x20 /* Lane Equalization Control Register */ #define PCI_PL_16GT_LE_CTRL_DSP_TX_PRESET_MASK 0x0000000F #define PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_MASK 0x000000F0 #define PCI_PL_16GT_LE_CTRL_USP_TX_PRESET_SHIFT 4 =20 /* Physical Layer 32.0 GT/s */ +#define PCI_PL_32GT_STATUS 0x0c /* 32.0 GT/s Status Register */ #define PCI_PL_32GT_LE_CTRL 0x20 /* Lane Equalization Control Register */ =20 /* Physical Layer 64.0 GT/s */ --- base-commit: d55d5a8f3d852baab49dba910dcb04b6d8091b05 change-id: 20260811-regdump-11719f75de0c Best regards, -- =20 Krishna Chaitanya Chundru