PCI: Add pcie_print_tlp_log() to print TLP Header and Prefix Log

Add pcie_print_tlp_log() to print TLP Header and Prefix Log.  Print End-End
Prefixes only if they are non-zero.

Consolidate the few places which currently print TLP using custom
formatting.

Link: https://lore.kernel.org/r/20250114170840.1633-9-ilpo.jarvinen@linux.intel.com
Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
[bhelgaas: commit log]
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/pci/pci.h

@@ -553,6 +553,8 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info);
 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);
+void pcie_print_tlp_log(const struct pci_dev *dev,
+			const struct pcie_tlp_log *log, const char *pfx);
 #endif	/* CONFIG_PCIEAER */
 
 #ifdef CONFIG_PCIEPORTBUS

drivers/pci/pcie/aer.c

@@ -665,12 +665,6 @@ static void pci_rootport_aer_stats_incr(struct pci_dev *pdev,
 	}
 }
 
-static void __print_tlp_header(struct pci_dev *dev, struct pcie_tlp_log *t)
-{
-	pci_err(dev, "  TLP Header: %08x %08x %08x %08x\n",
-		t->dw[0], t->dw[1], t->dw[2], t->dw[3]);
-}
-
 static void __aer_print_error(struct pci_dev *dev,
 			      struct aer_err_info *info)
 {
@@ -725,7 +719,7 @@ void aer_print_error(struct pci_dev *dev, struct aer_err_info *info)
 	__aer_print_error(dev, info);
 
 	if (info->tlp_header_valid)
-		__print_tlp_header(dev, &info->tlp);
+		pcie_print_tlp_log(dev, &info->tlp, dev_fmt("  "));
 
 out:
 	if (info->id && info->error_dev_num > 1 && info->id == id)
@@ -797,7 +791,7 @@ void pci_print_aer(struct pci_dev *dev, int aer_severity,
 			aer->uncor_severity);
 
 	if (tlp_header_valid)
-		__print_tlp_header(dev, &aer->header_log);
+		pcie_print_tlp_log(dev, &aer->header_log, dev_fmt("  "));
 
 	trace_aer_event(dev_name(&dev->dev), (status & ~mask),
 			aer_severity, tlp_header_valid, &aer->header_log);

drivers/pci/pcie/dpc.c

@@ -220,10 +220,7 @@ static void dpc_process_rp_pio_error(struct pci_dev *pdev)
 	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",
+	pcie_print_tlp_log(pdev, &tlp_log, dev_fmt(""));
-		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;

drivers/pci/pcie/tlp.c

@@ -6,6 +6,7 @@
  */
 
 #include <linux/aer.h>
+#include <linux/array_size.h>
 #include <linux/pci.h>
 #include <linux/string.h>
 
@@ -79,3 +80,36 @@ int pcie_read_tlp_log(struct pci_dev *dev, int where, int where2,
 
 	return 0;
 }
+
+#define EE_PREFIX_STR " E-E Prefixes:"
+
+/**
+ * pcie_print_tlp_log - Print TLP Header / Prefix Log contents
+ * @dev: PCIe device
+ * @log: TLP Log structure
+ * @pfx: String prefix
+ *
+ * Prints TLP Header and Prefix Log information held by @log.
+ */
+void pcie_print_tlp_log(const struct pci_dev *dev,
+			const struct pcie_tlp_log *log, const char *pfx)
+{
+	char buf[11 * (PCIE_STD_NUM_TLP_HEADERLOG + ARRAY_SIZE(log->prefix)) +
+		 sizeof(EE_PREFIX_STR)];
+	unsigned int i;
+	int len;
+
+	len = scnprintf(buf, sizeof(buf), "%#010x %#010x %#010x %#010x",
+			log->dw[0], log->dw[1], log->dw[2], log->dw[3]);
+
+	if (log->prefix[0])
+		len += scnprintf(buf + len, sizeof(buf) - len, EE_PREFIX_STR);
+	for (i = 0; i < ARRAY_SIZE(log->prefix); i++) {
+		if (!log->prefix[i])
+			break;
+		len += scnprintf(buf + len, sizeof(buf) - len,
+				 " %#010x", log->prefix[i]);
+	}
+
+	pci_err(dev, "%sTLP Header: %s\n", pfx, buf);
+}