PCI/AER: Clear error status registers during enumeration and restore

AER errors might be recorded when powering-on devices.  These errors can be
ignored, so firmware usually clears them before the OS enumerates devices.
However, firmware is not involved when devices are added via hotplug, so
the OS may discover power-up errors that should be ignored.  The same may
happen when powering up devices when resuming after suspend.

Clear the AER error status registers during enumeration and resume.

[bhelgaas: changelog, remove repetitive comments]
Signed-off-by: Taku Izumi <izumi.taku@jp.fujitsu.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

4 files changed, 39 insertions, 0 deletions

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 6a9a1116f1eb..62ecf45a4230 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -27,6 +27,7 @@
 #include <linux/pci_hotplug.h>
 #include <asm-generic/pci-bridge.h>
 #include <asm/setup.h>
+#include <linux/aer.h>
 #include "pci.h"
 
 const char *pci_power_names[] = {
@@ -1099,6 +1100,8 @@ void pci_restore_state(struct pci_dev *dev)
 	pci_restore_ats_state(dev);
 	pci_restore_vc_state(dev);
 
+	pci_cleanup_aer_error_status_regs(dev);
+
 	pci_restore_config_space(dev);
 
 	pci_restore_pcix_state(dev);
diff --git a/drivers/pci/pcie/aer/aerdrv_core.c b/drivers/pci/pcie/aer/aerdrv_core.c
index 9803e3d039fe..fba785e9df75 100644
--- a/drivers/pci/pcie/aer/aerdrv_core.c
+++ b/drivers/pci/pcie/aer/aerdrv_core.c
@@ -74,6 +74,34 @@ int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev)
 }
 EXPORT_SYMBOL_GPL(pci_cleanup_aer_uncorrect_error_status);
 
+int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
+{
+	int pos;
+	u32 status;
+	int port_type;
+
+	if (!pci_is_pcie(dev))
+		return -ENODEV;
+
+	pos = pci_find_ext_capability(dev, PCI_EXT_CAP_ID_ERR);
+	if (!pos)
+		return -EIO;
+
+	port_type = pci_pcie_type(dev);
+	if (port_type == PCI_EXP_TYPE_ROOT_PORT) {
+		pci_read_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, &status);
+		pci_write_config_dword(dev, pos + PCI_ERR_ROOT_STATUS, status);
+	}
+
+	pci_read_config_dword(dev, pos + PCI_ERR_COR_STATUS, &status);
+	pci_write_config_dword(dev, pos + PCI_ERR_COR_STATUS, status);
+
+	pci_read_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, &status);
+	pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, status);
+
+	return 0;
+}
+
 /**
  * add_error_device - list device to be handled
  * @e_info: pointer to error info
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 0b2be174d981..8cd9710498e4 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -12,6 +12,7 @@
 #include <linux/module.h>
 #include <linux/cpumask.h>
 #include <linux/pci-aspm.h>
+#include <linux/aer.h>
 #include <asm-generic/pci-bridge.h>
 #include "pci.h"
 
@@ -1621,6 +1622,8 @@ static void pci_init_capabilities(struct pci_dev *dev)
 
 	/* Enable ACS P2P upstream forwarding */
 	pci_enable_acs(dev);
+
+	pci_cleanup_aer_error_status_regs(dev);
 }
 
 static void pci_set_msi_domain(struct pci_dev *dev)
diff --git a/include/linux/aer.h b/include/linux/aer.h
index 4fef65e57023..744b997d6a94 100644
--- a/include/linux/aer.h
+++ b/include/linux/aer.h
@@ -42,6 +42,7 @@ struct aer_capability_regs {
 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);
 #else
 static inline int pci_enable_pcie_error_reporting(struct pci_dev *dev)
 {
@@ -55,6 +56,10 @@ static inline int pci_cleanup_aer_uncorrect_error_status(struct pci_dev *dev)
 {
 	return -EINVAL;
 }
+static inline int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
+{
+	return -EINVAL;
+}
 #endif
 
 void cper_print_aer(struct pci_dev *dev, int cper_severity,