PCI/AER: Save AER Capability for suspend/resume

Previously we did not save and restore the AER configuration on
suspend/resume, so the configuration may be lost after resume.

Save the AER configuration during suspend and restore it during resume.

[bhelgaas: commit log]
Link: https://lore.kernel.org/r/92EBB4272BF81E4089A7126EC1E7B28492C3B007@IRSMSX101.ger.corp.intel.com
Signed-off-by: Mayurkumar Patel <mayurkumar.patel@intel.com>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>

drivers/pci/access.c

@@ -355,7 +355,7 @@ static inline bool pcie_cap_has_sltctl(const struct pci_dev *dev)
 	       pcie_caps_reg(dev) & PCI_EXP_FLAGS_SLOT;
 }
 
-static inline bool pcie_cap_has_rtctl(const struct pci_dev *dev)
+bool pcie_cap_has_rtctl(const struct pci_dev *dev)
 {
 	int type = pci_pcie_type(dev);
 

drivers/pci/pci.c

@@ -1361,6 +1361,7 @@ int pci_save_state(struct pci_dev *dev)
 
 	pci_save_ltr_state(dev);
 	pci_save_dpc_state(dev);
+	pci_save_aer_state(dev);
 	return pci_save_vc_state(dev);
 }
 EXPORT_SYMBOL(pci_save_state);
@@ -1474,6 +1475,7 @@ void pci_restore_state(struct pci_dev *dev)
 	pci_restore_dpc_state(dev);
 
 	pci_cleanup_aer_error_status_regs(dev);
+	pci_restore_aer_state(dev);
 
 	pci_restore_config_space(dev);
 

drivers/pci/pci.h

@@ -12,6 +12,7 @@ extern const unsigned char pcie_link_speed[];
 extern bool pci_early_dump;
 
 bool pcie_cap_has_lnkctl(const struct pci_dev *dev);
+bool pcie_cap_has_rtctl(const struct pci_dev *dev);
 
 /* Functions internal to the PCI core code */
 

drivers/pci/pcie/aer.c

@@ -448,12 +448,70 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
 	return 0;
 }
 
+void pci_save_aer_state(struct pci_dev *dev)
+{
+	struct pci_cap_saved_state *save_state;
+	u32 *cap;
+	int pos;
+
+	pos = dev->aer_cap;
+	if (!pos)
+		return;
+
+	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
+	if (!save_state)
+		return;
+
+	cap = &save_state->cap.data[0];
+	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, cap++);
+	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, cap++);
+	pci_read_config_dword(dev, pos + PCI_ERR_COR_MASK, cap++);
+	pci_read_config_dword(dev, pos + PCI_ERR_CAP, cap++);
+	if (pcie_cap_has_rtctl(dev))
+		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, cap++);
+}
+
+void pci_restore_aer_state(struct pci_dev *dev)
+{
+	struct pci_cap_saved_state *save_state;
+	u32 *cap;
+	int pos;
+
+	pos = dev->aer_cap;
+	if (!pos)
+		return;
+
+	save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
+	if (!save_state)
+		return;
+
+	cap = &save_state->cap.data[0];
+	pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_MASK, *cap++);
+	pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_SEVER, *cap++);
+	pci_write_config_dword(dev, pos + PCI_ERR_COR_MASK, *cap++);
+	pci_write_config_dword(dev, pos + PCI_ERR_CAP, *cap++);
+	if (pcie_cap_has_rtctl(dev))
+		pci_write_config_dword(dev, pos + PCI_ERR_ROOT_COMMAND, *cap++);
+}
+
 void pci_aer_init(struct pci_dev *dev)
 {
-	dev->aer_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
+	int n;
 
-	if (dev->aer_cap)
+	dev->aer_cap = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
-		dev->aer_stats = kzalloc(sizeof(struct aer_stats), GFP_KERNEL);
+	if (!dev->aer_cap)
+		return;
+
+	dev->aer_stats = kzalloc(sizeof(struct aer_stats), GFP_KERNEL);
+
+	/*
+	 * We save/restore PCI_ERR_UNCOR_MASK, PCI_ERR_UNCOR_SEVER,
+	 * PCI_ERR_COR_MASK, and PCI_ERR_CAP.  Root and Root Complex Event
+	 * Collectors also implement PCI_ERR_ROOT_COMMAND (PCIe r5.0, sec
+	 * 7.8.4).
+	 */
+	n = pcie_cap_has_rtctl(dev) ? 5 : 4;
+	pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_ERR, sizeof(u32) * n);
 
 	pci_cleanup_aer_error_status_regs(dev);
 }

include/linux/aer.h

@@ -46,6 +46,8 @@ int pci_enable_pcie_error_reporting(struct pci_dev *dev);
 int pci_disable_pcie_error_reporting(struct pci_dev *dev);
 int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev);
 int pci_cleanup_aer_error_status_regs(struct pci_dev *dev);
+void pci_save_aer_state(struct pci_dev *dev);
+void pci_restore_aer_state(struct pci_dev *dev);
 #else
 static inline int pci_enable_pcie_error_reporting(struct pci_dev *dev)
 {
@@ -63,6 +65,8 @@ static inline int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
 {
 	return -EINVAL;
 }
+static inline void pci_save_aer_state(struct pci_dev *dev) {}
+static inline void pci_restore_aer_state(struct pci_dev *dev) {}
 #endif
 
 void cper_print_aer(struct pci_dev *dev, int aer_severity,