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PCI/AER: Add pci_aer_raw_clear_status() to unconditionally clear Error Status

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Per the SFI _OSC and DPC Updates ECN [1] implementation note flowchart, the
OS seems to be expected to clear AER status even if it doesn't have
ownership of the AER capability.  Unlike the DPC capability, where a DPC
ECN [2] specifies a window when the OS is allowed to access DPC registers
even if it doesn't have ownership, there is no clear model for AER.

Add pci_aer_raw_clear_status() to clear the AER error status registers
unconditionally.  This is intended for use only by the EDR path (see [2]).

[1] System Firmware Intermediary (SFI) _OSC and DPC Updates ECN, Feb 24,
    2020, affecting PCI Firmware Specification, Rev. 3.2
    https://members.pcisig.com/wg/PCI-SIG/document/14076
[2] Downstream Port Containment Related Enhancements ECN, Jan 28, 2019,
    affecting PCI Firmware Specification, Rev. 3.2
    https://members.pcisig.com/wg/PCI-SIG/document/12888

[bhelgaas: changelog]
Link: https://lore.kernel.org/r/c19ad28f3633cce67448609e89a75635da0da07d.1585000084.git.sathyanarayanan.kuppuswamy@linux.intel.com
Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
This commit is contained in:
Kuppuswamy Sathyanarayanan 2020-03-23 17:26:05 -07:00 committed by Bjorn Helgaas
parent 2700561817
commit 20e15e673b
2 changed files with 20 additions and 4 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

2
drivers/pci/pci.h
View file

@ -654,12 +654,14 @@ void pci_aer_exit(struct pci_dev *dev);
extern const struct attribute_group aer_stats_attr_group;
void pci_aer_clear_fatal_status(struct pci_dev *dev);
void pci_aer_clear_device_status(struct pci_dev *dev);
int pci_aer_raw_clear_status(struct pci_dev *dev);
#else
static inline void pci_no_aer(void) { }
static inline void pci_aer_init(struct pci_dev *d) { }
static inline void pci_aer_exit(struct pci_dev *d) { }
static inline void pci_aer_clear_fatal_status(struct pci_dev *dev) { }
static inline void pci_aer_clear_device_status(struct pci_dev *dev) { }
static inline int pci_aer_raw_clear_status(struct pci_dev *dev) { return -EINVAL; }
#endif
#ifdef CONFIG_ACPI

22
drivers/pci/pcie/aer.c
View file

@ -420,7 +420,16 @@ void pci_aer_clear_fatal_status(struct pci_dev *dev)
pci_write_config_dword(dev, pos + PCI_ERR_UNCOR_STATUS, status);
}
int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
/**
* pci_aer_raw_clear_status - Clear AER error registers.
* @dev: the PCI device
*
* Clearing AER error status registers unconditionally, regardless of
* whether they're owned by firmware or the OS.
*
* Returns 0 on success, or negative on failure.
*/
int pci_aer_raw_clear_status(struct pci_dev *dev)
{
int pos;
u32 status;
@ -433,9 +442,6 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
if (!pos)
return -EIO;
if (pcie_aer_get_firmware_first(dev))
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);
@ -451,6 +457,14 @@ int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
return 0;
}
int pci_cleanup_aer_error_status_regs(struct pci_dev *dev)
{
if (pcie_aer_get_firmware_first(dev))
return -EIO;
return pci_aer_raw_clear_status(dev);
}
void pci_save_aer_state(struct pci_dev *dev)
{
struct pci_cap_saved_state *save_state;