[PATCH v9 8/8] PCI: Create helper to print TLP Header and Prefix Log

Ilpo Järvinen
2025-01-14T17:10:03Z

Add pcie_print_tlp_log() helper 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.

The first attempt used pr_cont() instead of building a string first but
it turns out pr_cont() is not compatible with pci_err() and prints on a
separate line. When I asked about this, Andy Shevchenko suggested
pr_cont() should not be used in the first place (to eventually get rid
of it) so pr_cont() is now replaced with building the string first.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
drivers/pci/pci.h | 2 ++
drivers/pci/pcie/aer.c | 10 ++--------
drivers/pci/pcie/dpc.c | 5 +----
drivers/pci/pcie/tlp.c | 34 ++++++++++++++++++++++++++++++++++
4 files changed, 39 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index 7797b2544d00..797ad43a7683 100644
--- a/drivers/pci/pci.h
+++ b/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
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 656dbf1ac45b..ece8cb88d110 100644
--- a/drivers/pci/pcie/aer.c
+++ b/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);
diff --git a/drivers/pci/pcie/dpc.c b/drivers/pci/pcie/dpc.c
index 0aa20bc58697..242cabd5eeeb 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/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",
- 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]);
+ pcie_print_tlp_log(pdev, &tlp_log, dev_fmt(""));

if (pdev->dpc_rp_log_size < PCIE_STD_NUM_TLP_HEADERLOG + 1)
goto clear_status;
diff --git a/drivers/pci/pcie/tlp.c b/drivers/pci/pcie/tlp.c
index 2f029deebc33..7eb88d1b37b7 100644
--- a/drivers/pci/pcie/tlp.c
+++ b/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);
+}
--
2.39.5