[PATCH v9 12/15] PCI/RCEC: Add RCiEP's linked RCEC to AER/ERR

[Sean V Kelley <seanvk.dev@oregontracks.org>]

From: Qiuxu Zhuo <qiuxu.zhuo@intel.com>

When attempting error recovery for an RCiEP associated with an RCEC device,
there needs to be a way to update the Root Error Status, the Uncorrectable
Error Status and the Uncorrectable Error Severity of the parent RCEC.  In
some non-native cases in which there is no OS-visible device associated
with the RCiEP, there is nothing to act upon as the firmware is acting
before the OS.

Add handling for the linked RCEC in AER/ERR while taking into account
non-native cases.

Co-developed-by: Sean V Kelley <sean.v.kelley@intel.com>
Link: https://lore.kernel.org/r/20201002184735.1229220-12-seanvk.dev@oregontracks.org
Signed-off-by: Sean V Kelley <sean.v.kelley@intel.com>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
---
 drivers/pci/pcie/aer.c | 53 ++++++++++++++++++++++++++++++------------
 drivers/pci/pcie/err.c | 20 ++++++++--------
 2 files changed, 48 insertions(+), 25 deletions(-)

diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index 65dff5f3457a..083f69b67bfd 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -1357,27 +1357,50 @@ static int aer_probe(struct pcie_device *dev)
  */
 static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
 {
-	int aer = dev->aer_cap;
+	int type = pci_pcie_type(dev);
+	struct pci_dev *root;
+	int aer = 0;
+	int rc = 0;
 	u32 reg32;
-	int rc;
 
+	if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END)
+		/*
+		 * The reset should only clear the Root Error Status
+		 * of the RCEC. Only perform this for the
+		 * native case, i.e., an RCEC is present.
+		 */
+		root = dev->rcec;
+	else
+		root = dev;
 
-	/* Disable Root's interrupt in response to error messages */
-	pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
-	reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
-	pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+	if (root)
+		aer = dev->aer_cap;
 
-	rc = pci_bus_error_reset(dev);
-	pci_info(dev, "Root Port link has been reset\n");
+	if (aer) {
+		/* Disable Root's interrupt in response to error messages */
+		pci_read_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, &reg32);
+		reg32 &= ~ROOT_PORT_INTR_ON_MESG_MASK;
+		pci_write_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, reg32);
 
-	/* Clear Root Error Status */
-	pci_read_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, &reg32);
-	pci_write_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, reg32);
+		/* Clear Root Error Status */
+		pci_read_config_dword(root, aer + PCI_ERR_ROOT_STATUS, &reg32);
+		pci_write_config_dword(root, aer + PCI_ERR_ROOT_STATUS, reg32);
 
-	/* Enable Root Port's interrupt in response to error messages */
-	pci_read_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, &reg32);
-	reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
-	pci_write_config_dword(dev, aer + PCI_ERR_ROOT_COMMAND, reg32);
+		/* Enable Root Port's interrupt in response to error messages */
+		pci_read_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, &reg32);
+		reg32 |= ROOT_PORT_INTR_ON_MESG_MASK;
+		pci_write_config_dword(root, aer + PCI_ERR_ROOT_COMMAND, reg32);
+	}
+
+	if ((type == PCI_EXP_TYPE_RC_EC) || (type == PCI_EXP_TYPE_RC_END)) {
+		if (pcie_has_flr(root)) {
+			rc = pcie_flr(root);
+			pci_info(dev, "has been reset (%d)\n", rc);
+		}
+	} else {
+		rc = pci_bus_error_reset(root);
+		pci_info(dev, "Root Port link has been reset (%d)\n", rc);
+	}
 
 	return rc ? PCI_ERS_RESULT_DISCONNECT : PCI_ERS_RESULT_RECOVERED;
 }
diff --git a/drivers/pci/pcie/err.c b/drivers/pci/pcie/err.c
index 7883c9791562..cbc5abfe767b 100644
--- a/drivers/pci/pcie/err.c
+++ b/drivers/pci/pcie/err.c
@@ -148,10 +148,10 @@ static int report_resume(struct pci_dev *dev, void *data)
 
 /**
  * pci_walk_bridge - walk bridges potentially AER affected
- * @bridge:	bridge which may be a Port, an RCEC with associated RCiEPs,
- *		or an RCiEP associated with an RCEC
- * @cb:		callback to be called for each device found
- * @userdata:	arbitrary pointer to be passed to callback
+ * @bridge   bridge which may be an RCEC with associated RCiEPs,
+ *           or a Port.
+ * @cb       callback to be called for each device found
+ * @userdata arbitrary pointer to be passed to callback.
  *
  * If the device provided is a bridge, walk the subordinate bus, including
  * any bridged devices on buses under this bus.  Call the provided callback
@@ -164,8 +164,14 @@ static void pci_walk_bridge(struct pci_dev *bridge,
 			    int (*cb)(struct pci_dev *, void *),
 			    void *userdata)
 {
+	/*
+	 * In a non-native case where there is no OS-visible reporting
+	 * device the bridge will be NULL, i.e., no RCEC, no Downstream Port.
+	 */
 	if (bridge->subordinate)
 		pci_walk_bus(bridge->subordinate, cb, userdata);
+	else if (bridge->rcec)
+		cb(bridge->rcec, userdata);
 	else
 		cb(bridge, userdata);
 }
@@ -194,12 +200,6 @@ pci_ers_result_t pcie_do_recovery(struct pci_dev *dev,
 	pci_dbg(bridge, "broadcast error_detected message\n");
 	if (state == pci_channel_io_frozen) {
 		pci_walk_bridge(bridge, report_frozen_detected, &status);
-		if (type == PCI_EXP_TYPE_RC_END) {
-			pci_warn(dev, "subordinate device reset not possible for RCiEP\n");
-			status = PCI_ERS_RESULT_NONE;
-			goto failed;
-		}
-
 		status = reset_subordinates(bridge);
 		if (status != PCI_ERS_RESULT_RECOVERED) {
 			pci_warn(bridge, "subordinate device reset failed\n");
-- 
2.28.0