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PCI: Add support for ACPI _RST reset method

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_RST is a standard ACPI method that performs a function level reset of a
device (ACPI v6.3, sec 7.3.25).

Add pci_dev_acpi_reset() to probe for _RST method and execute if present.
The default priority of this reset is set to below device-specific and
above hardware resets.

Suggested-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20210817180500.1253-9-ameynarkhede03@gmail.com
Signed-off-by: Shanker Donthineni <sdonthineni@nvidia.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Sinan Kaya <okaya@kernel.org>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Shanker Donthineni 2021-08-17 23:34:59 +05:30 committed by Bjorn Helgaas
parent 375553a932
commit 6937b7dd43
4 changed files with 31 additions and 1 deletions
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23
drivers/pci/pci-acpi.c
View file

@ -941,6 +941,29 @@ void pci_set_acpi_fwnode(struct pci_dev *dev)
acpi_pci_find_companion(&dev->dev));
}
/**
* pci_dev_acpi_reset - do a function level reset using _RST method
* @dev: device to reset
* @probe: check if _RST method is included in the acpi_device context.
*/
int pci_dev_acpi_reset(struct pci_dev *dev, int probe)
{
acpi_handle handle = ACPI_HANDLE(&dev->dev);
if (!handle || !acpi_has_method(handle, "_RST"))
return -ENOTTY;
if (probe)
return 0;
if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, NULL))) {
pci_warn(dev, "ACPI _RST failed\n");
return -ENOTTY;
}
return 0;
}
static bool acpi_pci_power_manageable(struct pci_dev *dev)
{
struct acpi_device *adev = ACPI_COMPANION(&dev->dev);

1
drivers/pci/pci.c
View file

@ -5126,6 +5126,7 @@ static void pci_dev_restore(struct pci_dev *dev)
static const struct pci_reset_fn_method pci_reset_fn_methods[] = {
{ },
{ pci_dev_specific_reset, .name = "device_specific" },
{ pci_dev_acpi_reset, .name = "acpi" },
{ pcie_reset_flr, .name = "flr" },
{ pci_af_flr, .name = "af_flr" },
{ pci_pm_reset, .name = "pm" },

6
drivers/pci/pci.h
View file

@ -708,7 +708,13 @@ static inline int pci_aer_raw_clear_status(struct pci_dev *dev) { return -EINVAL
int pci_acpi_program_hp_params(struct pci_dev *dev);
extern const struct attribute_group pci_dev_acpi_attr_group;
void pci_set_acpi_fwnode(struct pci_dev *dev);
int pci_dev_acpi_reset(struct pci_dev *dev, int probe);
#else
static inline int pci_dev_acpi_reset(struct pci_dev *dev, int probe)
{
return -ENOTTY;
}
static inline void pci_set_acpi_fwnode(struct pci_dev *dev) {}
static inline int pci_acpi_program_hp_params(struct pci_dev *dev)
{

2
include/linux/pci.h
View file

@ -50,7 +50,7 @@
PCI_STATUS_PARITY)
/* Number of reset methods used in pci_reset_fn_methods array in pci.c */
#define PCI_NUM_RESET_METHODS 6
#define PCI_NUM_RESET_METHODS 7
/*
* The PCI interface treats multi-function devices as independent