[PATCH v6 08/10] PCI/AER: Add pcie_walk_rcec() to RCEC AER handling

[Sean V Kelley]

From: Sean V Kelley <sean.v.kelley@xxxxxxxxx>

The Root Complex Event Collectors(RCEC) appear as peers to Root Ports
and also have the AER capability. In addition, actions need to be taken
for assocated RCiEPs. In such cases the RCECs will need to be walked in
order to find and act upon their respective RCiEPs.  Extend the existing
ability to link the RCECs with a walking function pcie_walk_rcec(). Add
RCEC support to the current AER service driver and attach the AER service
driver to the RCEC device.

Co-developed-by: Qiuxu Zhuo <qiuxu.zhuo@xxxxxxxxx>
Signed-off-by: Qiuxu Zhuo <qiuxu.zhuo@xxxxxxxxx>
Signed-off-by: Sean V Kelley <sean.v.kelley@xxxxxxxxx>
---
 drivers/pci/pci.h       |  4 ++++
 drivers/pci/pcie/aer.c  | 27 ++++++++++++++++++++-------
 drivers/pci/pcie/rcec.c | 39 ++++++++++++++++++++++++++++++++++++++-
 3 files changed, 62 insertions(+), 8 deletions(-)

diff --git a/drivers/pci/pci.h b/drivers/pci/pci.h
index ddb5872466fb..e8535a7d4b53 100644
--- a/drivers/pci/pci.h
+++ b/drivers/pci/pci.h
@@ -475,10 +475,14 @@ static inline void pci_dpc_init(struct pci_dev *pdev) {}
 void pci_rcec_init(struct pci_dev *dev);
 void pci_rcec_exit(struct pci_dev *dev);
 void pcie_link_rcec(struct pci_dev *rcec);
+void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *),
+		    void *userdata);
 #else
 static inline void pci_rcec_init(struct pci_dev *dev) {}
 static inline void pci_rcec_exit(struct pci_dev *dev) {}
 static inline void pcie_link_rcec(struct pci_dev *rcec) {}
+static inline void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *),
+				  void *userdata) {}
 #endif
 
 #ifdef CONFIG_PCI_ATS
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index dccdba60b5d9..43772bfc134e 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -300,7 +300,7 @@ int pci_aer_raw_clear_status(struct pci_dev *dev)
 		return -EIO;
 
 	port_type = pci_pcie_type(dev);
-	if (port_type == PCI_EXP_TYPE_ROOT_PORT) {
+	if (port_type == PCI_EXP_TYPE_ROOT_PORT || port_type == PCI_EXP_TYPE_RC_EC) {
 		pci_read_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, &status);
 		pci_write_config_dword(dev, aer + PCI_ERR_ROOT_STATUS, status);
 	}
@@ -595,7 +595,8 @@ static umode_t aer_stats_attrs_are_visible(struct kobject *kobj,
 	if ((a == &dev_attr_aer_rootport_total_err_cor.attr ||
 	     a == &dev_attr_aer_rootport_total_err_fatal.attr ||
 	     a == &dev_attr_aer_rootport_total_err_nonfatal.attr) &&
-	    pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT)
+	    ((pci_pcie_type(pdev) != PCI_EXP_TYPE_ROOT_PORT) &&
+	    (pci_pcie_type(pdev) != PCI_EXP_TYPE_RC_EC)))
 		return 0;
 
 	return a->mode;
@@ -916,7 +917,10 @@ static bool find_source_device(struct pci_dev *parent,
 	if (result)
 		return true;
 
-	pci_walk_bus(parent->subordinate, find_device_iter, e_info);
+	if (pci_pcie_type(parent) == PCI_EXP_TYPE_RC_EC)
+		pcie_walk_rcec(parent, find_device_iter, e_info);
+	else
+		pci_walk_bus(parent->subordinate, find_device_iter, e_info);
 
 	if (!e_info->error_dev_num) {
 		pci_info(parent, "can't find device of ID%04x\n", e_info->id);
@@ -1053,6 +1057,7 @@ int aer_get_device_error_info(struct pci_dev *dev, struct aer_err_info *info)
 		if (!(info->status & ~info->mask))
 			return 0;
 	} else if (pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
+		   pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC ||
 	           pci_pcie_type(dev) == PCI_EXP_TYPE_DOWNSTREAM ||
 		   info->severity == AER_NONFATAL) {
 
@@ -1205,6 +1210,7 @@ static int set_device_error_reporting(struct pci_dev *dev, void *data)
 	int type = pci_pcie_type(dev);
 
 	if ((type == PCI_EXP_TYPE_ROOT_PORT) ||
+	    (type == PCI_EXP_TYPE_RC_EC) ||
 	    (type == PCI_EXP_TYPE_UPSTREAM) ||
 	    (type == PCI_EXP_TYPE_DOWNSTREAM)) {
 		if (enable)
@@ -1229,9 +1235,11 @@ static void set_downstream_devices_error_reporting(struct pci_dev *dev,
 {
 	set_device_error_reporting(dev, &enable);
 
-	if (!dev->subordinate)
-		return;
-	pci_walk_bus(dev->subordinate, set_device_error_reporting, &enable);
+	if (pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC)
+		pcie_walk_rcec(dev, set_device_error_reporting, &enable);
+	else if (dev->subordinate)
+		pci_walk_bus(dev->subordinate, set_device_error_reporting, &enable);
+
 }
 
 /**
@@ -1329,6 +1337,11 @@ static int aer_probe(struct pcie_device *dev)
 	struct device *device = &dev->device;
 	struct pci_dev *port = dev->port;
 
+	/* Limit to Root Ports or Root Complex Event Collectors */
+	if ((pci_pcie_type(port) != PCI_EXP_TYPE_RC_EC) &&
+	    (pci_pcie_type(port) != PCI_EXP_TYPE_ROOT_PORT))
+		return -ENODEV;
+
 	rpc = devm_kzalloc(device, sizeof(struct aer_rpc), GFP_KERNEL);
 	if (!rpc)
 		return -ENOMEM;
@@ -1385,7 +1398,7 @@ static pci_ers_result_t aer_root_reset(struct pci_dev *dev)
 
 static struct pcie_port_service_driver aerdriver = {
 	.name		= "aer",
-	.port_type	= PCI_EXP_TYPE_ROOT_PORT,
+	.port_type	= PCIE_ANY_PORT,
 	.service	= PCIE_PORT_SERVICE_AER,
 
 	.probe		= aer_probe,
diff --git a/drivers/pci/pcie/rcec.c b/drivers/pci/pcie/rcec.c
index 5630480a6659..e6d20131b578 100644
--- a/drivers/pci/pcie/rcec.c
+++ b/drivers/pci/pcie/rcec.c
@@ -53,7 +53,18 @@ static int link_rcec_helper(struct pci_dev *dev, void *data)
 	return 0;
 }
 
-void walk_rcec(int (*cb)(struct pci_dev *dev, void *data), void *userdata)
+static int walk_rcec_helper(struct pci_dev *dev, void *data)
+{
+	struct walk_rcec_data *rcec_data = data;
+	struct pci_dev *rcec = rcec_data->rcec;
+
+	if ((pci_pcie_type(dev) == PCI_EXP_TYPE_RC_END) && rcec_assoc_rciep(rcec, dev))
+		rcec_data->user_callback(dev, rcec_data->user_data);
+
+	return 0;
+}
+
+static void walk_rcec(int (*cb)(struct pci_dev *dev, void *data), void *userdata)
 {
 	struct walk_rcec_data *rcec_data = userdata;
 	struct pci_dev *rcec = rcec_data->rcec;
@@ -113,6 +124,32 @@ void pcie_link_rcec(struct pci_dev *rcec)
 	walk_rcec(link_rcec_helper, &rcec_data);
 }
 
+/**
+ * pcie_walk_rcec - Walk RCiEP devices associating with RCEC and call callback.
+ * @rcec     RCEC whose RCiEP devices should be walked.
+ * @cb       Callback to be called for each RCiEP device found.
+ * @userdata Arbitrary pointer to be passed to callback.
+ *
+ * Walk the given RCEC. Call the provided callback on each RCiEP device found.
+ *
+ * We check the return of @cb each time. If it returns anything
+ * other than 0, we break out.
+ */
+void pcie_walk_rcec(struct pci_dev *rcec, int (*cb)(struct pci_dev *, void *),
+		    void *userdata)
+{
+	struct walk_rcec_data rcec_data;
+
+	if (!rcec->rcec_cap)
+		return;
+
+	rcec_data.rcec = rcec;
+	rcec_data.user_callback = cb;
+	rcec_data.user_data = userdata;
+
+	walk_rcec(walk_rcec_helper, &rcec_data);
+}
+
 void pci_rcec_init(struct pci_dev *dev)
 {
 	u32 rcec, hdr, busn;
-- 
2.28.0