On 2/2/21 12:32 PM, Russ Weight wrote:

On 9/17/20 1:28 PM, Tom Rix wrote:

quoted

On 9/17/20 11:32 AM, Russ Weight wrote:

quoted

Port enable is not complete until ACK = 0. Change
__afu_port_enable() to guarantee that the enable process
is complete by polling for ACK == 0.

Signed-off-by: Russ Weight <redacted>
---
 drivers/fpga/dfl-afu-error.c |  2 +-
 drivers/fpga/dfl-afu-main.c  | 29 +++++++++++++++++++++--------
 drivers/fpga/dfl-afu.h       |  2 +-
 3 files changed, 23 insertions(+), 10 deletions(-)

diff --git a/drivers/fpga/dfl-afu-error.c b/drivers/fpga/dfl-afu-error.c
index c4691187cca9..0806532a3e9f 100644
--- a/drivers/fpga/dfl-afu-error.c
+++ b/drivers/fpga/dfl-afu-error.c

@@ -103,7 +103,7 @@ static int afu_port_err_clear(struct device *dev, u64 err)
 	__afu_port_err_mask(dev, false);
 

There is an earlier bit that sets ret = -EINVAL.

This error will be lost or not handled well.

Right now it doesn't seem to be handled.

Good catch. I'll give priority to -EINVAL in the next version of the
patch, as it is more informative in the context of this function.

Actually - Hao pointed out in his response that the falure to re-enable the port
is a more serious error, so the code flow OK, but needs a comment.

- Russ

quoted

quoted

 	/* Enable the Port by clear the reset */
-	__afu_port_enable(pdev);
+	ret = __afu_port_enable(pdev);
 
 done:
 	mutex_unlock(&pdata->lock);

diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
index 753cda4b2568..f73b06cdf13c 100644
--- a/drivers/fpga/dfl-afu-main.c
+++ b/drivers/fpga/dfl-afu-main.c

@@ -21,6 +21,9 @@
 
 #include "dfl-afu.h"
 
+#define RST_POLL_INVL 10 /* us */
+#define RST_POLL_TIMEOUT 1000 /* us */
+
 /**
  * __afu_port_enable - enable a port by clear reset
  * @pdev: port platform device.

@@ -32,7 +35,7 @@
  *
  * The caller needs to hold lock for protection.
  */
-void __afu_port_enable(struct platform_device *pdev)
+int __afu_port_enable(struct platform_device *pdev)
 {
 	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
 	void __iomem *base;

@@ -41,7 +44,7 @@ void __afu_port_enable(struct platform_device *pdev)
 	WARN_ON(!pdata->disable_count);
 
 	if (--pdata->disable_count != 0)
-		return;
+		return 0;

Is this really a success ? Maybe -EBUSY ?

Yilun addressed this question in his previous response. This isessentially a
reference count for nested disable calls. Weonly do the enable if the
disable count has gone to zero, so this isn't an error condition.

quoted

quoted

 
 	base = dfl_get_feature_ioaddr_by_id(&pdev->dev, PORT_FEATURE_ID_HEADER);
 

@@ -49,10 +52,20 @@ void __afu_port_enable(struct platform_device *pdev)
 	v = readq(base + PORT_HDR_CTRL);
 	v &= ~PORT_CTRL_SFTRST;
 	writeq(v, base + PORT_HDR_CTRL);
-}
 
-#define RST_POLL_INVL 10 /* us */
-#define RST_POLL_TIMEOUT 1000 /* us */
+	/*
+	 * HW clears the ack bit to indicate that the port is fully out
+	 * of reset.
+	 */
+	if (readq_poll_timeout(base + PORT_HDR_CTRL, v,
+			       !(v & PORT_CTRL_SFTRST_ACK),
+			       RST_POLL_INVL, RST_POLL_TIMEOUT)) {
+		dev_err(&pdev->dev, "timeout, failure to enable device\n");
+		return -ETIMEDOUT;
+	}
+
+	return 0;
+}
 
 /**
  * __afu_port_disable - disable a port by hold reset

@@ -111,7 +124,7 @@ static int __port_reset(struct platform_device *pdev)
 
 	ret = __afu_port_disable(pdev);
 	if (!ret)
-		__afu_port_enable(pdev);
+		ret = __afu_port_enable(pdev);
 
 	return ret;
 }

@@ -872,11 +885,11 @@ static int afu_dev_destroy(struct platform_device *pdev)
 static int port_enable_set(struct platform_device *pdev, bool enable)
 {
 	struct dfl_feature_platform_data *pdata = dev_get_platdata(&pdev->dev);
-	int ret = 0;
+	int ret;
 
 	mutex_lock(&pdata->lock);
 	if (enable)
-		__afu_port_enable(pdev);
+		ret = __afu_port_enable(pdev);
 	else
 		ret = __afu_port_disable(pdev);
 	mutex_unlock(&pdata->lock);

diff --git a/drivers/fpga/dfl-afu.h b/drivers/fpga/dfl-afu.h
index 576e94960086..e5020e2b1f3d 100644
--- a/drivers/fpga/dfl-afu.h
+++ b/drivers/fpga/dfl-afu.h

@@ -80,7 +80,7 @@ struct dfl_afu {
 };
 
 /* hold pdata->lock when call __afu_port_enable/disable */
-void __afu_port_enable(struct platform_device *pdev);
+int __afu_port_enable(struct platform_device *pdev);
 int __afu_port_disable(struct platform_device *pdev);

The other functions in this file have afu_*  since the __afu_port_enable/disable

are used other places would it make sense to remove the '__' prefix ?

If you think so, maybe a cleanup patch later.

Yilun and Hao addressed this comment in their previous responses. We are using the
'__' prefix to indicate highlight the fact caller needs to use care in managing
the locking associated with these functions.

Thanks,
- Russ

quoted

Tom

quoted

 
 void afu_mmio_region_init(struct dfl_feature_platform_data *pdata);