[PATCH v2 0/2] PCI: Consolidate TLP Log reading and printing

[PATCH v2 0/2] PCI: Consolidate TLP Log reading and printing

[Ilpo Järvinen]

This series has the remaining patches of the AER & DPC TLP Log handling
consolidation.

v2:
- Don't add EXPORT()s
- Don't include igxbe changes
- Don't use pr_cont() as it's incompatible with pci_err() and according
  to Andy Shevchenko should not be used in the first place

Ilpo Järvinen (2):
  PCI: Add TLP Prefix reading into pcie_read_tlp_log()
  PCI: Create helper to print TLP Header and Prefix Log

 drivers/pci/ats.c             |  2 +-
 drivers/pci/pci.c             | 66 +++++++++++++++++++++++++++++++----
 drivers/pci/pcie/aer.c        | 14 +++-----
 drivers/pci/pcie/dpc.c        | 23 +++++++-----
 drivers/pci/probe.c           | 14 +++++---
 include/linux/aer.h           |  7 +++-
 include/linux/pci.h           |  2 +-
 include/uapi/linux/pci_regs.h |  2 ++
 8 files changed, 98 insertions(+), 32 deletions(-)

-- 
2.39.2

[PATCH v2 1/2] PCI: Add TLP Prefix reading into pcie_read_tlp_log()

[Ilpo Järvinen]

pcie_read_tlp_log() handles only 4 TLP 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 layout of relevant registers in AER and DPC
Capability is not identical but the offsets of TLP Header Log and TLP
Prefix Log vary so the callers must pass the offsets to
pcie_read_tlp_log().

Convert eetlp_prefix_path into integer called eetlp_prefix_max and
make is available also when CONFIG_PCI_PASID is not configured to
be able to determine the number of E-E Prefixes.

Signed-off-by: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com>
---
 drivers/pci/ats.c             |  2 +-
 drivers/pci/pci.c             | 34 ++++++++++++++++++++++++++++------
 drivers/pci/pcie/aer.c        |  4 +++-
 drivers/pci/pcie/dpc.c        | 22 +++++++++++++++-------
 drivers/pci/probe.c           | 14 +++++++++-----
 include/linux/aer.h           |  5 ++++-
 include/linux/pci.h           |  2 +-
 include/uapi/linux/pci_regs.h |  2 ++
 8 files changed, 63 insertions(+), 22 deletions(-)

diff --git a/drivers/pci/ats.c b/drivers/pci/ats.c
index c570892b2090..e13433dcfc82 100644
--- a/drivers/pci/ats.c
+++ b/drivers/pci/ats.c
@@ -377,7 +377,7 @@ int pci_enable_pasid(struct pci_dev *pdev, int features)
 	if (WARN_ON(pdev->pasid_enabled))
 		return -EBUSY;
 
-	if (!pdev->eetlp_prefix_path && !pdev->pasid_no_tlp)
+	if (!pdev->eetlp_prefix_max && !pdev->pasid_no_tlp)
 		return -EINVAL;
 
 	if (!pasid)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index e5f243dd4288..af230e6e5557 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1066,26 +1066,48 @@ static void pci_enable_acs(struct pci_dev *dev)
 	pci_disable_acs_redir(dev);
 }
 
+/**
+ * aer_tlp_log_len - Calculates 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;
+}
+
 /**
  * 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 (in DWORDs)
  * @tlp_log: TLP Log structure to fill
  *
  * Fill @tlp_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 *tlp_log)
+int pcie_read_tlp_log(struct pci_dev *dev, int where, int where2,
+		      unsigned int tlp_len, struct pcie_tlp_log *tlp_log)
 {
-	int i, ret;
+	unsigned int i;
+	int off, ret;
+	u32 *to;
 
 	memset(tlp_log, 0, sizeof(*tlp_log));
 
-	for (i = 0; i < 4; i++) {
-		ret = pci_read_config_dword(dev, where + i * 4,
-					    &tlp_log->dw[i]);
+	for (i = 0; i < tlp_len; i++) {
+		if (i < 4) {
+			to = &tlp_log->dw[i];
+			off = where + i * 4;
+		} else {
+			to = &tlp_log->prefix[i - 4];
+			off = where2 + (i - 4) * 4;
+		}
+
+		ret = pci_read_config_dword(dev, off, to);
 		if (ret)
 			return pcibios_err_to_errno(ret);
 	}
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index ac6293c24976..ecc1dea5a208 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 a668820696dc..80b1456f95fe 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -187,10 +187,19 @@ pci_ers_result_t dpc_reset_link(struct pci_dev *pdev)
 	return ret;
 }
 
+static unsigned int dpc_tlp_log_len(struct pci_dev *pdev)
+{
+	/* Remove ImpSpec Log register from the count */
+	if (pdev->dpc_rp_log_size >= 5)
+		return pdev->dpc_rp_log_size - 1;
+
+	return pdev->dpc_rp_log_size;
+}
+
 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 +226,19 @@ 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/probe.c b/drivers/pci/probe.c
index 1325fbae2f28..02035b005a53 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2211,8 +2211,8 @@ static void pci_configure_relaxed_ordering(struct pci_dev *dev)
 
 static void pci_configure_eetlp_prefix(struct pci_dev *dev)
 {
-#ifdef CONFIG_PCI_PASID
 	struct pci_dev *bridge;
+	unsigned int eetlp_max;
 	int pcie_type;
 	u32 cap;
 
@@ -2224,15 +2224,19 @@ static void pci_configure_eetlp_prefix(struct pci_dev *dev)
 		return;
 
 	pcie_type = pci_pcie_type(dev);
+
+	eetlp_max = FIELD_GET(PCI_EXP_DEVCAP2_EE_PREFIX_MAX, cap);
+	/* 00b means 4 */
+	eetlp_max = eetlp_max ?: 4;
+
 	if (pcie_type == PCI_EXP_TYPE_ROOT_PORT ||
 	    pcie_type == PCI_EXP_TYPE_RC_END)
-		dev->eetlp_prefix_path = 1;
+		dev->eetlp_prefix_max = eetlp_max;
 	else {
 		bridge = pci_upstream_bridge(dev);
-		if (bridge && bridge->eetlp_prefix_path)
-			dev->eetlp_prefix_path = 1;
+		if (bridge && bridge->eetlp_prefix_max)
+			dev->eetlp_prefix_max = eetlp_max;
 	}
-#endif
 }
 
 static void pci_configure_serr(struct pci_dev *dev)
diff --git a/include/linux/aer.h b/include/linux/aer.h
index 4b97f38f3fcf..2484056feb8d 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 {
@@ -37,7 +38,9 @@ struct aer_capability_regs {
 	u16 uncor_err_source;
 };
 
-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);
 
 #if defined(CONFIG_PCIEAER)
 int pci_aer_clear_nonfatal_status(struct pci_dev *dev);
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 16493426a04f..71f505862ef0 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -397,7 +397,7 @@ struct pci_dev {
 					   supported from root to here */
 #endif
 	unsigned int	pasid_no_tlp:1;		/* PASID works without TLP Prefix */
-	unsigned int	eetlp_prefix_path:1;	/* End-to-End TLP Prefix */
+	unsigned int	eetlp_prefix_max:3;	/* Max # of End-to-End TLP Prefix, 0=not supported */
 
 	pci_channel_state_t error_state;	/* Current connectivity state */
 	struct device	dev;			/* Generic device interface */
diff --git a/include/uapi/linux/pci_regs.h b/include/uapi/linux/pci_regs.h
index a39193213ff2..cf7a07fa4a3b 100644
--- a/include/uapi/linux/pci_regs.h
+++ b/include/uapi/linux/pci_regs.h
@@ -661,6 +661,7 @@
 #define  PCI_EXP_DEVCAP2_OBFF_MSG	0x00040000 /* New message signaling */
 #define  PCI_EXP_DEVCAP2_OBFF_WAKE	0x00080000 /* Re-use WAKE# for OBFF */
 #define  PCI_EXP_DEVCAP2_EE_PREFIX	0x00200000 /* End-End TLP Prefix */
+#define  PCI_EXP_DEVCAP2_EE_PREFIX_MAX	0x00c00000 /* Max End-End TLP Prefixes */
 #define PCI_EXP_DEVCTL2		0x28	/* Device Control 2 */
 #define  PCI_EXP_DEVCTL2_COMP_TIMEOUT	0x000f	/* Completion Timeout Value */
 #define  PCI_EXP_DEVCTL2_COMP_TMOUT_DIS	0x0010	/* Completion Timeout Disable */
@@ -802,6 +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

Re: [PATCH v2 1/2] PCI: Add TLP Prefix reading into pcie_read_tlp_log()

[Lukas Wunner]

On Wed, Apr 03, 2024 at 01:02:05PM +0300, Ilpo Järvinen wrote:
> pcie_read_tlp_log() handles only 4 TLP 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 layout of relevant registers in AER and DPC
> Capability is not identical but the offsets of TLP Header Log and TLP
                ^^^           ^^^
Somehow this doesn't seem to make sense.  Is the "not" perhaps wrong here?

> Prefix Log vary so the callers must pass the offsets to
> pcie_read_tlp_log().

Re: [PATCH v2 1/2] PCI: Add TLP Prefix reading into pcie_read_tlp_log()

[Ilpo Järvinen]

[-- Attachment #1: Type: text/plain, Size: 888 bytes --]

On Thu, 4 Apr 2024, Lukas Wunner wrote:

> On Wed, Apr 03, 2024 at 01:02:05PM +0300, Ilpo Järvinen wrote:
> > pcie_read_tlp_log() handles only 4 TLP 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 layout of relevant registers in AER and DPC
> > Capability is not identical but the offsets of TLP Header Log and TLP
>                 ^^^           ^^^
> Somehow this doesn't seem to make sense.  Is the "not" perhaps wrong here?

Hi Lukas,

How about changing it into plural and adding a comma:

The layouts of relevant registers in AER and DPC Capabilities are not 
identical, but ...

Does that sound better?

> > Prefix Log vary so the callers must pass the offsets to
> > pcie_read_tlp_log().


-- 
 i.

[PATCH v2 2/2] PCI: Create helper to print TLP Header and Prefix Log

[Ilpo Järvinen]

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() but 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>
---
 drivers/pci/pci.c      | 32 ++++++++++++++++++++++++++++++++
 drivers/pci/pcie/aer.c | 10 ++--------
 drivers/pci/pcie/dpc.c |  5 +----
 include/linux/aer.h    |  2 ++
 4 files changed, 37 insertions(+), 12 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index af230e6e5557..54d4872d14b8 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/acpi.h>
+#include <linux/array_size.h>
 #include <linux/kernel.h>
 #include <linux/delay.h>
 #include <linux/dmi.h>
@@ -1116,6 +1117,37 @@ int pcie_read_tlp_log(struct pci_dev *dev, int where, int where2,
 }
 EXPORT_SYMBOL_GPL(pcie_read_tlp_log);
 
+/**
+ * pcie_print_tlp_log - Print TLP Header / Prefix Log contents
+ * @dev:	PCIe device
+ * @tlp_log:	TLP Log structure
+ * @pfx:	Internal string prefix (for indentation)
+ *
+ * Prints TLP Header and Prefix Log information held by @tlp_log.
+ */
+void pcie_print_tlp_log(const struct pci_dev *dev,
+			const struct pcie_tlp_log *tlp_log, const char *pfx)
+{
+	char buf[(10 + 1) * (4 + ARRAY_SIZE(tlp_log->prefix)) + 14 + 1];
+	unsigned int i;
+	int len;
+
+	len = scnprintf(buf, sizeof(buf), "%#010x %#010x %#010x %#010x",
+			tlp_log->dw[0], tlp_log->dw[1], tlp_log->dw[2],
+			tlp_log->dw[3]);
+
+	if (tlp_log->prefix[0])
+		len += scnprintf(buf + len, sizeof(buf) - len, " E-E Prefixes:");
+	for (i = 0; i < ARRAY_SIZE(tlp_log->prefix); i++) {
+		if (!tlp_log->prefix[i])
+			break;
+		len += scnprintf(buf + len, sizeof(buf) - len,
+				 " %#010x", tlp_log->prefix[i]);
+	}
+
+	pci_err(dev, "%sTLP Header: %s\n", pfx, buf);
+}
+
 /**
  * pci_restore_bars - restore a device's BAR values (e.g. after wake-up)
  * @dev: PCI device to have its BARs restored
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index ecc1dea5a208..efb9e728fe94 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -664,12 +664,6 @@ 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)
 {
@@ -724,7 +718,7 @@ 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, "  ");
 
 out:
 	if (info->id && info->error_dev_num > 1 && info->id == id)
@@ -796,7 +790,7 @@ 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, "  ");
 
 	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 80b1456f95fe..3f8e3b6c7948 100644
--- a/drivers/pci/pcie/dpc.c
+++ b/drivers/pci/pcie/dpc.c
@@ -229,10 +229,7 @@ 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 - 5; i++)
-		pci_err(pdev, "TLP Prefix Header: dw%d, %#010x\n", i, tlp_log.prefix[i]);
+	pcie_print_tlp_log(pdev, &tlp_log, "");
 
 	if (pdev->dpc_rp_log_size < 5)
 		goto clear_status;
diff --git a/include/linux/aer.h b/include/linux/aer.h
index 2484056feb8d..1e8c61deca65 100644
--- a/include/linux/aer.h
+++ b/include/linux/aer.h
@@ -41,6 +41,8 @@ struct aer_capability_regs {
 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);
+void pcie_print_tlp_log(const struct pci_dev *dev,
+			const struct pcie_tlp_log *tlp_log, const char *pfx);
 
 #if defined(CONFIG_PCIEAER)
 int pci_aer_clear_nonfatal_status(struct pci_dev *dev);
-- 
2.39.2