[PATCH v6 6/8] PCI: Add TLP Prefix reading into pcie_read_tlp_log()

Ilpo Järvinen
2024-09-13T14:38:00Z

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.

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>
---
drivers/pci/pci.h | 5 +++-
drivers/pci/pcie/aer.c | 4 ++-
drivers/pci/pcie/dpc.c | 13 +++++-----
drivers/pci/pcie/tlp.c | 49 +++++++++++++++++++++++++++++++----
include/linux/aer.h | 1 +
include/uapi/linux/pci_regs.h | 1 +
6 files changed, 59 insertions(+), 14 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 532bb05a0411..b47844b97428 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -483,7 +483,9 @@ 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);
#endif /* CONFIG_PCIEAER */

#ifdef CONFIG_PCIEPORTBUS
@@ -502,6 +504,7 @@ 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 13b8586924ea..651d0c72802a 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1245,7 +1245,9 @@ 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), &info->tlp);
}
}

diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 2b6ef7efa3c1..7933b3cedb59 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 < 4)
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 - 5; i++)
+ pci_err(pdev, "TLP Prefix Header: dw%d, %#010x\n", i, tlp_log.prefix[i]);

if (pdev->dpc_rp_log_size < 5)
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 - 5; 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 65ac7b5d8a87..def9dd7b73e8 100644
--- a/drivers/pci/pcie/tlp.c
+++ b/drivers/pci/pcie/tlp.c
@@ -11,26 +11,65 @@

#include "../pci.h"

+/**
+ * aer_tlp_log_len - Calculates AER Capability TLP Header/Prefix Log length
+ * @dev: PCIe device
+ *
+ * Return: TLP Header/Prefix Log length
+ */
+unsigned int aer_tlp_log_len(struct pci_dev *dev)
+{
+ return 4 + dev->eetlp_prefix_max;
+}
+
+#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 >= 5)
+ 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 < 4; i++) {
- ret = pci_read_config_dword(dev, where + i * 4, &log->dw[i]);
+ for (i = 0; i < tlp_len; i++) {
+ if (i < 4) {
+ off = where + i * 4;
+ to = &log->dw[i];
+ } else {
+ off = where2 + (i - 4) * 4;
+ to = &log->prefix[i - 4];
+ }
+
+ 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 190a0a2061cd..dc498adaa1c8 100644
--- a/include/linux/aer.h
+++ b/include/linux/aer.h
@@ -20,6 +20,7 @@ struct pci_dev;

struct pcie_tlp_log {
u32 dw[4];
+ u32 prefix[4];
};

struct aer_capability_regs {
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index b297bc30ddcb..b6f9012a3fc4 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -803,6 +803,7 @@
#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
--
2.39.2