Hi,
On 8/7/19 9:03 AM, Patel, Mayurkumar wrote:
This patch provides AER config save and restore capabilities. After system
resume AER config registers settings are lost. Not restoring AER root error
command register bits on root port if they were set, disables generation
of an AER interrupt reported by function as described in PCIe spec r4.0,
sec 7.8.4.9. Moreover, AER config mask, severity and ECRC registers are
also required to maintain same state prior to system suspend to maintain
AER interrupts behavior.
Looks good to me
Signed-off-by: Mayurkumar Patel <mayurkumar.patel@xxxxxxxxx>
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>
---
drivers/pci/pci.c | 2 ++
drivers/pci/pcie/aer.c | 70 ++++++++++++++++++++++++++++++++++++++++++++++++++
include/linux/aer.h | 4 +++
3 files changed, 76 insertions(+)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 8abc843..40d5507 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -1340,6 +1340,7 @@ 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);
@@ -1453,6 +1454,7 @@ 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);
diff --git a/drivers/pci/pcie/aer.c b/drivers/pci/pcie/aer.c
index b45bc47..fb067dc 100644
--- a/drivers/pci/pcie/aer.c
+++ b/drivers/pci/pcie/aer.c
@@ -448,6 +448,64 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
return 0;
}
+static inline bool pcie_aer_cap_has_root_command(struct pci_dev *dev)
+{
+ return pci_pcie_type(dev) == PCI_EXP_TYPE_ROOT_PORT ||
+ pci_pcie_type(dev) == PCI_EXP_TYPE_RC_EC;
+}
+
+void pci_save_aer_state(struct pci_dev *dev)
+{
+ struct pci_cap_saved_state *save_state;
+ u32 *cap;
+ int pos;
+
+ if (!pci_is_pcie(dev))
+ return;
+
+ save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
+ if (!save_state)
+ return;
+
+ pos = dev->aer_cap;
+ if (!pos)
+ 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_aer_cap_has_root_command(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;
+
+ if (!pci_is_pcie(dev))
+ return;
+
+ save_state = pci_find_saved_ext_cap(dev, PCI_EXT_CAP_ID_ERR);
+ if (!save_state)
+ return;
+
+ pos = dev->aer_cap;
+ if (!pos)
+ 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_aer_cap_has_root_command(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);
@@ -455,6 +513,18 @@ void pci_aer_init(struct pci_dev *dev)
if (dev->aer_cap)
dev->aer_stats = kzalloc(sizeof(struct aer_stats), GFP_KERNEL);
+ /*
+ * Since PCI_ERR_ROOT_COMMAND is only valid for root port and root
+ * complex event collector, as per PCIe 4.0 section 7.8.4, interpret
+ * the device/port type to determine the availability of additional
+ * root port and root complex event collector register.
+ */
+ if (pcie_aer_cap_has_root_command(dev))
+ pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_ERR,
+ sizeof(u32) * 5);
+ else
+ pci_add_ext_cap_save_buffer(dev, PCI_EXT_CAP_ID_ERR,
+ sizeof(u32) * 4);
pci_cleanup_aer_error_status_regs(dev);
}
diff --git a/include/linux/aer.h b/include/linux/aer.h
index 514bffa..fa19e01 100644
--- a/include/linux/aer.h
+++ b/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,
--
Sathyanarayanan Kuppuswamy
Linux kernel developer
