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

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  [PATCH 3/5] PCI: make pci_flr_wait() generic and rename to pci_dev_wait() Sinan Kaya <okaya@codeaurora.org> - 2017-09-24 02:20 +0200
    Re: [PATCH 3/5] PCI: make pci_flr_wait() generic and rename to  pci_dev_wait() Christoph Hellwig <hch@infradead.org> - 2017-09-24 15:10 +0200
      Re: [PATCH 3/5] PCI: make pci_flr_wait() generic and rename to  pci_dev_wait() Sinan Kaya <okaya@codeaurora.org> - 2017-09-25 02:40 +0200

#1738090 — [PATCH 3/5] PCI: make pci_flr_wait() generic and rename to pci_dev_wait()

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

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#1738182 — Re: [PATCH 3/5] PCI: make pci_flr_wait() generic and rename to pci_dev_wait()

On Sat, Sep 23, 2017 at 08:16:56PM -0400, Sinan Kaya wrote:
> 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.

Maybe call it pci_reset_wait instead of pci_dev_wait?

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#1738611 — Re: [PATCH 3/5] PCI: make pci_flr_wait() generic and rename to pci_dev_wait()

On 9/24/2017 9:08 AM, Christoph Hellwig wrote:
> On Sat, Sep 23, 2017 at 08:16:56PM -0400, Sinan Kaya wrote:
>> 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.
> 
> Maybe call it pci_reset_wait instead of pci_dev_wait?
> 

I can go for pci_dev_reset_wait(). I was using the PCI directory function
naming nomenclature where some functions using struct pci_dev start with
pci_dev and others using struct pci_bus start with pci_bus.

-- 
Sinan Kaya
Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc.
Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.

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