PCI: Add TLP Prefix reading to pcie_read_tlp_log()

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 also handle 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.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Ilpo Järvinen <[email protected]>
[bhelgaas: squash ternary fix from
https://lore.kernel.org/r/[email protected]]
Signed-off-by: Bjorn Helgaas <[email protected]>
Reviewed-by: Jonathan Cameron <[email protected]>

Author: ij-intel

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) { }

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);
 		}
 	}
 

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);
 }

drivers/pci/pcie/tlp.c

@@ -11,26 +11,68 @@
 
 #include "../pci.h"
 
+/**
+ * aer_tlp_log_len - Calculate 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 - Calculate 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);
 	}

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 {

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