Commit 20e15e67 authored by Kuppuswamy Sathyanarayanan's avatar Kuppuswamy Sathyanarayanan Committed by Bjorn Helgaas
Browse files

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

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: default avatarKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 27005618

drivers/pci/pci.h

+2 −0
Original line number Diff line number Diff line
@@ -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

drivers/pci/pcie/aer.c

+18 −4
Original line number Diff line number Diff line
@@ -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;

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