From: Shanker Donthineni <sdonthineni () nvidia ! com>
The _RST is a standard method specified in the ACPI specification. It
provides a function level reset when it is described in the acpi_device
context associated with PCI-device.
Implement a new reset function pci_dev_acpi_reset() for probing RST
method and execute if it is defined in the firmware. The ACPI binding
information is available only after calling device_add(), so move
pci_init_reset_methods() to end of the pci_device_add().
The default priority of the acpi reset is set to below device-specific
and above hardware resets.
Signed-off-by: Shanker Donthineni <sdonthineni@xxxxxxxxxx>
---
drivers/pci/pci.c | 30 ++++++++++++++++++++++++++++++
drivers/pci/probe.c | 2 +-
include/linux/pci.h | 2 +-
3 files changed, 32 insertions(+), 2 deletions(-)
diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 664cf2d35..d39dba590 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -5076,6 +5076,35 @@ static void pci_dev_restore(struct pci_dev *dev)
err_handler->reset_done(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.
+ */
+static int pci_dev_acpi_reset(struct pci_dev *dev, int probe)
+{
+#ifdef CONFIG_ACPI
+ acpi_handle handle = ACPI_HANDLE(&dev->dev);
+
+ /* Return -ENOTTY if _RST method is not included in the dev context */
+ if (!handle || !acpi_has_method(handle, "_RST"))
+ return -ENOTTY;
+
+ /* Return 0 for probe phase indicating that we can reset this device */
+ if (probe)
+ return 0;
+
+ /* Invoke _RST() method to perform a function level reset */
+ if (ACPI_FAILURE(acpi_evaluate_object(handle, "_RST", NULL, NULL))) {
+ pci_warn(dev, "Failed to reset the device\n");
+ return -EINVAL;
+ }
+ return 0;
+#else
+ return -ENOTTY;
+#endif
+}
+
/*
* The ordering for functions in pci_reset_fn_methods
* is required for reset_methods byte array defined
@@ -5083,6 +5112,7 @@ static void pci_dev_restore(struct pci_dev *dev)
*/
const struct pci_reset_fn_method pci_reset_fn_methods[] = {
{ .reset_fn = &pci_dev_specific_reset, .name = "device_specific" },
+ { .reset_fn = &pci_dev_acpi_reset, .name = "acpi" },
{ .reset_fn = &pcie_reset_flr, .name = "flr" },
{ .reset_fn = &pci_af_flr, .name = "af_flr" },
{ .reset_fn = &pci_pm_reset, .name = "pm" },
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 4764e031a..d4becd6ff 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -2403,7 +2403,6 @@ static void pci_init_capabilities(struct pci_dev *dev)
pci_rcec_init(dev); /* Root Complex Event Collector */
pcie_report_downtraining(dev);
- pci_init_reset_methods(dev);
}
/*
@@ -2494,6 +2493,7 @@ void pci_device_add(struct pci_dev *dev, struct pci_bus *bus)
dev->match_driver = false;
ret = device_add(&dev->dev);
WARN_ON(ret < 0);
+ pci_init_reset_methods(dev);
}
struct pci_dev *pci_scan_single_device(struct pci_bus *bus, int devfn)
diff --git a/include/linux/pci.h b/include/linux/pci.h
index 9f8347799..b4a5d2146 100644
--- a/include/linux/pci.h
+++ b/include/linux/pci.h
@@ -49,7 +49,7 @@
PCI_STATUS_SIG_TARGET_ABORT | \
PCI_STATUS_PARITY)
-#define PCI_RESET_FN_METHODS 5
+#define PCI_RESET_FN_METHODS 6
/*
* The PCI interface treats multi-function devices as independent
--
2.31.1
