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PCI: Add array to track reset method ordering

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Add reset_methods[] in struct pci_dev to keep track of reset mechanisms
supported by the device and their ordering.

Refactor probing and reset functions to take advantage of calling
convention of reset functions.

Co-developed-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20210817180500.1253-4-ameynarkhede03@gmail.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Amey Narkhede <ameynarkhede03@gmail.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Reviewed-by: Raphael Norwitz <raphael.norwitz@nutanix.com>
This commit is contained in:
Amey Narkhede
2021-08-17 23:34:54 +05:30
committed by Bjorn Helgaas
parent 56f107d781
commit e20afa0624
4 changed files with 69 additions and 44 deletions
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94
drivers/pci/pci.c
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@@ -73,6 +73,11 @@ static void pci_dev_d3_sleep(struct pci_dev *dev)
msleep(delay);
}
bool pci_reset_supported(struct pci_dev *dev)
{
return dev->reset_methods[0] != 0;
}
#ifdef CONFIG_PCI_DOMAINS
int pci_domains_supported = 1;
#endif
@@ -5117,6 +5122,16 @@ static void pci_dev_restore(struct pci_dev *dev)
err_handler->reset_done(dev);
}
/* dev->reset_methods[] is a 0-terminated list of indices into this array */
static const struct pci_reset_fn_method pci_reset_fn_methods[] = {
{ },
{ pci_dev_specific_reset, .name = "device_specific" },
{ pcie_reset_flr, .name = "flr" },
{ pci_af_flr, .name = "af_flr" },
{ pci_pm_reset, .name = "pm" },
{ pci_reset_bus_function, .name = "bus" },
};
/**
* __pci_reset_function_locked - reset a PCI device function while holding
* the @dev mutex lock.
@@ -5139,65 +5154,64 @@ static void pci_dev_restore(struct pci_dev *dev)
*/
int __pci_reset_function_locked(struct pci_dev *dev)
{
int rc;
int i, m, rc = -ENOTTY;
might_sleep();
/*
* A reset method returns -ENOTTY if it doesn't support this device
* and we should try the next method.
* A reset method returns -ENOTTY if it doesn't support this device and
* we should try the next method.
*
* If it returns 0 (success), we're finished. If it returns any
* other error, we're also finished: this indicates that further
* reset mechanisms might be broken on the device.
* If it returns 0 (success), we're finished. If it returns any other
* error, we're also finished: this indicates that further reset
* mechanisms might be broken on the device.
*/
rc = pci_dev_specific_reset(dev, 0);
if (rc != -ENOTTY)
return rc;
rc = pcie_reset_flr(dev, 0);
if (rc != -ENOTTY)
return rc;
rc = pci_af_flr(dev, 0);
if (rc != -ENOTTY)
return rc;
rc = pci_pm_reset(dev, 0);
if (rc != -ENOTTY)
return rc;
return pci_reset_bus_function(dev, 0);
for (i = 0; i < PCI_NUM_RESET_METHODS; i++) {
m = dev->reset_methods[i];
if (!m)
return -ENOTTY;
rc = pci_reset_fn_methods[m].reset_fn(dev, 0);
if (!rc)
return 0;
if (rc != -ENOTTY)
return rc;
}
return -ENOTTY;
}
EXPORT_SYMBOL_GPL(__pci_reset_function_locked);
/**
* pci_probe_reset_function - check whether the device can be safely reset
* @dev: PCI device to reset
* pci_init_reset_methods - check whether device can be safely reset
* and store supported reset mechanisms.
* @dev: PCI device to check for reset mechanisms
*
* Some devices allow an individual function to be reset without affecting
* other functions in the same device. The PCI device must be responsive
* to PCI config space in order to use this function.
* other functions in the same device. The PCI device must be in D0-D3hot
* state.
*
* Returns 0 if the device function can be reset or negative if the
* device doesn't support resetting a single function.
* Stores reset mechanisms supported by device in reset_methods byte array
* which is a member of struct pci_dev.
*/
int pci_probe_reset_function(struct pci_dev *dev)
void pci_init_reset_methods(struct pci_dev *dev)
{
int rc;
int m, i, rc;
BUILD_BUG_ON(ARRAY_SIZE(pci_reset_fn_methods) != PCI_NUM_RESET_METHODS);
might_sleep();
rc = pci_dev_specific_reset(dev, 1);
if (rc != -ENOTTY)
return rc;
rc = pcie_reset_flr(dev, 1);
if (rc != -ENOTTY)
return rc;
rc = pci_af_flr(dev, 1);
if (rc != -ENOTTY)
return rc;
rc = pci_pm_reset(dev, 1);
if (rc != -ENOTTY)
return rc;
i = 0;
for (m = 1; m < PCI_NUM_RESET_METHODS; m++) {
rc = pci_reset_fn_methods[m].reset_fn(dev, 1);
if (!rc)
dev->reset_methods[i++] = m;
else if (rc != -ENOTTY)
break;
}
return pci_reset_bus_function(dev, 1);
dev->reset_methods[i] = 0;
}
/**