[PATCH 3/5] PCI: make pci_flr_wait() generic and rename to pci_dev_wait()

Sinan Kaya
2017-09-24T00:17:12Z

Rev 3.1 Sec 2.3.1 Request Handling Rules:
Valid reset conditions after which a device is permitted to return CRS
are:
* Cold, Warm, and Hot Resets,
* FLR
* A reset initiated in response to a D3hot to D0 uninitialized

Try to reuse FLR implementation towards other reset types.

Signed-off-by: Sinan Kaya <okaya@codeaurora.org>
---
drivers/pci/pci.c | 45 ++++++++++++++++++++++++++++-----------------
1 file changed, 28 insertions(+), 17 deletions(-)

diff --git a/drivers/pci/pci.c b/drivers/pci/pci.c
index 27ec45d..fd4a3b6 100644
--- a/drivers/pci/pci.c
+++ b/drivers/pci/pci.c
@@ -3820,20 +3820,14 @@ int pci_wait_for_pending_transaction(struct pci_dev *dev)
}
EXPORT_SYMBOL(pci_wait_for_pending_transaction);

-static int pci_flr_wait(struct pci_dev *dev)
+static int pci_dev_wait(struct pci_dev *dev, char *reset_type,
+ int initial_wait, int timeout)
{
- int delay = 1, timeout = 60000;
+ int delay = 1;
u32 id;

/*
- * Per PCIe r3.1, sec 6.6.2, a device must complete an FLR within
- * 100ms, but may silently discard requests while the FLR is in
- * progress. Wait 100ms before trying to access the device.
- */
- msleep(100);
-
- /*
- * After 100ms, the device should not silently discard config
+ * After reset, the device should not silently discard config
* requests, but it may still indicate that it needs more time by
* responding to them with CRS completions. The Root Port will
* generally synthesize ~0 data to complete the read (except when
@@ -3847,14 +3841,14 @@ static int pci_flr_wait(struct pci_dev *dev)
pci_read_config_dword(dev, PCI_COMMAND, &id);
while (id == ~0) {
if (delay > timeout) {
- dev_warn(&dev->dev, "not ready %dms after FLR; giving up\n",
- 100 + delay - 1);
+ dev_warn(&dev->dev, "not ready %dms after %s; giving up\n",
+ initial_wait + delay - 1, reset_type);
return -ENOTTY;
}

if (delay > 1000)
- dev_info(&dev->dev, "not ready %dms after FLR; waiting\n",
- 100 + delay - 1);
+ dev_info(&dev->dev, "not ready %dms after %s; waiting\n",
+ initial_wait + delay - 1, reset_type);

msleep(delay);
delay *= 2;
@@ -3862,7 +3856,8 @@ static int pci_flr_wait(struct pci_dev *dev)
}

if (delay > 1000)
- dev_info(&dev->dev, "ready %dms after FLR\n", 100 + delay - 1);
+ dev_info(&dev->dev, "ready %dms after %s\n",
+ initial_wait + delay - 1, reset_type);

return 0;
}
@@ -3899,7 +3894,15 @@ int pcie_flr(struct pci_dev *dev)
dev_err(&dev->dev, "timed out waiting for pending transaction; performing function level reset anyway\n");

pcie_capability_set_word(dev, PCI_EXP_DEVCTL, PCI_EXP_DEVCTL_BCR_FLR);
- return pci_flr_wait(dev);
+
+ /*
+ * Per PCIe r3.1, sec 6.6.2, a device must complete an FLR within
+ * 100ms, but may silently discard requests while the FLR is in
+ * progress. Wait 100ms before trying to access the device.
+ */
+ msleep(100);
+
+ return pci_dev_wait(dev, "FLR", 100, 60000);
}
EXPORT_SYMBOL_GPL(pcie_flr);

@@ -3932,7 +3935,15 @@ static int pci_af_flr(struct pci_dev *dev, int probe)
dev_err(&dev->dev, "timed out waiting for pending transaction; performing AF function level reset anyway\n");

pci_write_config_byte(dev, pos + PCI_AF_CTRL, PCI_AF_CTRL_FLR);
- return pci_flr_wait(dev);
+
+ /*
+ * Per PCIe r3.1, sec 6.6.2, a device must complete an FLR within
+ * 100ms, but may silently discard requests while the FLR is in
+ * progress. Wait 100ms before trying to access the device.
+ */
+ msleep(100);
+
+ return pci_dev_wait(dev, "AF_FLR", 100, 60000);
}

/**
--
1.9.1