[PATCH v9 7/8] PCI: Add TLP Prefix reading into pcie_read_tlp_log()

Ilpo Järvinen
2025-01-14T17:09:53Z

pcie_read_tlp_log() handles only 4 Header Log DWORDs but TLP Prefix Log
(PCIe r6.1 secs 7.8.4.12 & 7.9.14.13) may also be present.

Generalize pcie_read_tlp_log() and struct pcie_tlp_log to handle also
TLP Prefix Log. The relevant registers are formatted identically in AER
and DPC Capability, but has these variations:

a) The offsets of TLP Prefix Log registers vary.
b) DPC RP PIO TLP Prefix Log register can be < 4 DWORDs.
c) AER TLP Prefix Log Present (PCIe r6.1 sec 7.8.4.7) can indicate
Prefix Log is not present.

Therefore callers must pass the offset of the TLP Prefix Log register
and the entire length to pcie_read_tlp_log() to be able to read the
correct number of TLP Prefix DWORDs from the correct offset.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
drivers/pci/pci.h | 5 +++-
drivers/pci/pcie/aer.c | 5 +++-
drivers/pci/pcie/dpc.c | 13 ++++-----
drivers/pci/pcie/tlp.c | 52 +++++++++++++++++++++++++++++++----
include/linux/aer.h | 1 +
include/uapi/linux/pci_regs.h | 10 ++++---
6 files changed, 68 insertions(+), 18 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 55fcf3bac4f7..7797b2544d00 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -550,7 +550,9 @@ struct aer_err_info {
int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info);
void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);

-int pcie_read_tlp_log(struct pci_dev *dev, int where, struct pcie_tlp_log *log);
+int pcie_read_tlp_log(struct pci_dev *dev, int where, int where2,
+ unsigned int tlp_len, struct pcie_tlp_log *log);
+unsigned int aer_tlp_log_len(struct pci_dev *dev, u32 aercc);
#endif /* CONFIG_PCIEAER */

#ifdef CONFIG_PCIEPORTBUS
@@ -569,6 +571,7 @@ void pci_dpc_init(struct pci_dev *pdev);
void dpc_process_error(struct pci_dev *pdev);
pci_ers_result_t dpc_reset_link(struct pci_dev *pdev);
bool pci_dpc_recovered(struct pci_dev *pdev);
+unsigned int dpc_tlp_log_len(struct pci_dev *dev);
#else
static inline void pci_save_dpc_state(struct pci_dev *dev) { }
static inline void pci_restore_dpc_state(struct pci_dev *dev) { }
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 80c5ba8d8296..656dbf1ac45b 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1248,7 +1248,10 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)

if (info->status & AER_LOG_TLP_MASKS) {
info->tlp_header_valid = 1;
- pcie_read_tlp_log(dev, aer + PCI_ERR_HEADER_LOG, &info->tlp);
+ pcie_read_tlp_log(dev, aer + PCI_ERR_HEADER_LOG,
+ aer + PCI_ERR_PREFIX_LOG,
+ aer_tlp_log_len(dev, aercc),
+ &info->tlp);
}
}

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 0674d8c89bfa..0aa20bc58697 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -190,7 +190,7 @@ pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
static void dpc_process_rp_pio_error(struct pci_dev *pdev)
{
u16 cap = pdev->dpc_cap, dpc_status, first_error;
- u32 status, mask, sev, syserr, exc, log, prefix;
+ u32 status, mask, sev, syserr, exc, log;
struct pcie_tlp_log tlp_log;
int i;

@@ -217,20 +217,19 @@ static void dpc_process_rp_pio_error(struct pci_dev *pdev)

if (pdev->dpc_rp_log_size < PCIE_STD_NUM_TLP_HEADERLOG)
goto clear_status;
- pcie_read_tlp_log(pdev, cap + PCI_EXP_DPC_RP_PIO_HEADER_LOG, &tlp_log);
+ pcie_read_tlp_log(pdev, cap + PCI_EXP_DPC_RP_PIO_HEADER_LOG,
+ cap + PCI_EXP_DPC_RP_PIO_TLPPREFIX_LOG,
+ dpc_tlp_log_len(pdev), &tlp_log);
pci_err(pdev, "TLP Header: %#010x %#010x %#010x %#010x\n",
tlp_log.dw[0], tlp_log.dw[1], tlp_log.dw[2], tlp_log.dw[3]);
+ for (i = 0; i < pdev->dpc_rp_log_size - PCIE_STD_NUM_TLP_HEADERLOG - 1; i++)
+ pci_err(pdev, "TLP Prefix Header: dw%d, %#010x\n", i, tlp_log.prefix[i]);

if (pdev->dpc_rp_log_size < PCIE_STD_NUM_TLP_HEADERLOG + 1)
goto clear_status;
pci_read_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_IMPSPEC_LOG, &log);
pci_err(pdev, "RP PIO ImpSpec Log %#010x\n", log);

- for (i = 0; i < pdev->dpc_rp_log_size - PCIE_STD_NUM_TLP_HEADERLOG - 1; i++) {
- pci_read_config_dword(pdev,
- cap + PCI_EXP_DPC_RP_PIO_TLPPREFIX_LOG + i * 4, &prefix);
- pci_err(pdev, "TLP Prefix Header: dw%d, %#010x\n", i, prefix);
- }
clear_status:
pci_write_config_dword(pdev, cap + PCI_EXP_DPC_RP_PIO_STATUS, status);
}
diff --git a/drivers/pci/pcie/tlp.c b/drivers/pci/pcie/tlp.c
index d7ad99f466b9..2f029deebc33 100644
--- a/drivers/pci/pcie/tlp.c
+++ b/drivers/pci/pcie/tlp.c
@@ -11,26 +11,68 @@

#include "../pci.h"

+/**
+ * aer_tlp_log_len - Calculates AER Capability TLP Header/Prefix Log length
+ * @dev: PCIe device
+ * @aercc: AER Capabilities and Control register value
+ *
+ * Return: TLP Header/Prefix Log length
+ */
+unsigned int aer_tlp_log_len(struct pci_dev *dev, u32 aercc)
+{
+ return PCIE_STD_NUM_TLP_HEADERLOG +
+ (aercc & PCI_ERR_CAP_PREFIX_LOG_PRESENT) ?
+ dev->eetlp_prefix_max : 0;
+}
+
+#ifdef CONFIG_PCIE_DPC
+/**
+ * dpc_tlp_log_len - Calculates DPC RP PIO TLP Header/Prefix Log length
+ * @dev: PCIe device
+ *
+ * Return: TLP Header/Prefix Log length
+ */
+unsigned int dpc_tlp_log_len(struct pci_dev *dev)
+{
+ /* Remove ImpSpec Log register from the count */
+ if (dev->dpc_rp_log_size >= PCIE_STD_NUM_TLP_HEADERLOG + 1)
+ return dev->dpc_rp_log_size - 1;
+
+ return dev->dpc_rp_log_size;
+}
+#endif
+
/**
* pcie_read_tlp_log - read TLP Header Log
* @dev: PCIe device
* @where: PCI Config offset of TLP Header Log
+ * @where2: PCI Config offset of TLP Prefix Log
+ * @tlp_len: TLP Log length (Header Log + TLP Prefix Log in DWORDs)
* @log: TLP Log structure to fill
*
* Fill @log from TLP Header Log registers, e.g., AER or DPC.
*
* Return: 0 on success and filled TLP Log structure, <0 on error.
*/
-int pcie_read_tlp_log(struct pci_dev *dev, int where,
- struct pcie_tlp_log *log)
+int pcie_read_tlp_log(struct pci_dev *dev, int where, int where2,
+ unsigned int tlp_len, struct pcie_tlp_log *log)
{
unsigned int i;
- int ret;
+ int off, ret;
+ u32 *to;

memset(log, 0, sizeof(*log));

- for (i = 0; i < PCIE_STD_NUM_TLP_HEADERLOG; i++) {
- ret = pci_read_config_dword(dev, where + i * 4, &log->dw[i]);
+ for (i = 0; i < tlp_len; i++) {
+ if (i < PCIE_STD_NUM_TLP_HEADERLOG) {
+ off = where + i * 4;
+ to = &log->dw[i];
+ } else {
+ off = where2 + (i - PCIE_STD_NUM_TLP_HEADERLOG) * 4;
+ to = &log->prefix[i - PCIE_STD_NUM_TLP_HEADERLOG];
+ }
+
+ ret = pci_read_config_dword(dev, off, to);
if (ret)
return pcibios_err_to_errno(ret);
}
diff --git a/include/linux/aer.h b/include/linux/aer.h
index 4ef6515c3205..947b63091902 100644
--- a/include/linux/aer.h
+++ b/include/linux/aer.h
@@ -27,6 +27,7 @@ struct pci_dev;

struct pcie_tlp_log {
u32 dw[PCIE_STD_NUM_TLP_HEADERLOG];
+ u32 prefix[PCIE_STD_MAX_TLP_PREFIXLOG];
};

struct aer_capability_regs {
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index 14a6306c4ce1..82866ac0bda7 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -790,10 +790,11 @@
/* Same bits as above */
#define PCI_ERR_CAP 0x18 /* Advanced Error Capabilities & Ctrl*/
#define PCI_ERR_CAP_FEP(x) ((x) & 0x1f) /* First Error Pointer */
-#define PCI_ERR_CAP_ECRC_GENC 0x00000020 /* ECRC Generation Capable */
-#define PCI_ERR_CAP_ECRC_GENE 0x00000040 /* ECRC Generation Enable */
-#define PCI_ERR_CAP_ECRC_CHKC 0x00000080 /* ECRC Check Capable */
-#define PCI_ERR_CAP_ECRC_CHKE 0x00000100 /* ECRC Check Enable */
+#define PCI_ERR_CAP_ECRC_GENC 0x00000020 /* ECRC Generation Capable */
+#define PCI_ERR_CAP_ECRC_GENE 0x00000040 /* ECRC Generation Enable */
+#define PCI_ERR_CAP_ECRC_CHKC 0x00000080 /* ECRC Check Capable */
+#define PCI_ERR_CAP_ECRC_CHKE 0x00000100 /* ECRC Check Enable */
+#define PCI_ERR_CAP_PREFIX_LOG_PRESENT 0x00000800 /* TLP Prefix Log Present */
#define PCI_ERR_HEADER_LOG 0x1c /* Header Log Register (16 bytes) */
#define PCI_ERR_ROOT_COMMAND 0x2c /* Root Error Command */
#define PCI_ERR_ROOT_CMD_COR_EN 0x00000001 /* Correctable Err Reporting Enable */
@@ -809,6 +810,7 @@
#define PCI_ERR_ROOT_FATAL_RCV 0x00000040 /* Fatal Received */
#define PCI_ERR_ROOT_AER_IRQ 0xf8000000 /* Advanced Error Interrupt Message Number */
#define PCI_ERR_ROOT_ERR_SRC 0x34 /* Error Source Identification */
+#define PCI_ERR_PREFIX_LOG 0x38 /* TLP Prefix LOG Register (up to 16 bytes) */

/* Virtual Channel */
#define PCI_VC_PORT_CAP1 0x04
--
2.39.5