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Date: Thu, 17 Sep 2020 11:32:19 -0700
From: Russ Weight <russell.h.weight@...el.com>
To: mdf@...nel.org, linux-fpga@...r.kernel.org,
linux-kernel@...r.kernel.org
Cc: trix@...hat.com, lgoncalv@...hat.com, yilun.xu@...el.com,
hao.wu@...el.com, matthew.gerlach@...el.com,
Russ Weight <russell.h.weight@...el.com>
Subject: [PATCH v2 1/1] fpga: dfl: afu: harden port enable logic
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 <russell.h.weight@...el.com>
---
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);
/* 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;
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);
void afu_mmio_region_init(struct dfl_feature_platform_data *pdata);
--
2.17.1
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