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Message-ID: <DM6PR11MB3819173E2C84099BA5D6EB4785B49@DM6PR11MB3819.namprd11.prod.outlook.com>
Date: Wed, 3 Feb 2021 09:01:27 +0000
From: "Wu, Hao" <hao.wu@...el.com>
To: "Weight, Russell H" <russell.h.weight@...el.com>,
"mdf@...nel.org" <mdf@...nel.org>,
"linux-fpga@...r.kernel.org" <linux-fpga@...r.kernel.org>,
"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC: "trix@...hat.com" <trix@...hat.com>,
"lgoncalv@...hat.com" <lgoncalv@...hat.com>,
"Xu, Yilun" <yilun.xu@...el.com>,
"Gerlach, Matthew" <matthew.gerlach@...el.com>,
"Weight, Russell H" <russell.h.weight@...el.com>
Subject: RE: [PATCH v3 1/1] fpga: dfl: afu: harden port enable logic
> Subject: [PATCH v3 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>
> ---
> v3:
> - afu_port_err_clear() changed to prioritize port_enable failure over
> other a detected mismatch in port errors.
> - reorganized code in port_reset() to be more readable.
> v2:
> - Fixed typo in commit message
> ---
> drivers/fpga/dfl-afu-error.c | 8 ++++----
> drivers/fpga/dfl-afu-main.c | 31 ++++++++++++++++++++++---------
> drivers/fpga/dfl-afu.h | 2 +-
> 3 files changed, 27 insertions(+), 14 deletions(-)
>
> diff --git a/drivers/fpga/dfl-afu-error.c b/drivers/fpga/dfl-afu-error.c
> index c4691187cca9..2ced610059cc 100644
> --- a/drivers/fpga/dfl-afu-error.c
> +++ b/drivers/fpga/dfl-afu-error.c
> @@ -52,7 +52,7 @@ static int afu_port_err_clear(struct device *dev, u64 err)
> struct dfl_feature_platform_data *pdata = dev_get_platdata(dev);
> struct platform_device *pdev = to_platform_device(dev);
> void __iomem *base_err, *base_hdr;
> - int ret = -EBUSY;
> + int enable_ret = 0, ret = -EBUSY;
> u64 v;
>
> base_err = dfl_get_feature_ioaddr_by_id(dev,
> PORT_FEATURE_ID_ERROR);
> @@ -102,12 +102,12 @@ static int afu_port_err_clear(struct device *dev, u64
> err)
> /* Clear mask */
> __afu_port_err_mask(dev, false);
>
> - /* Enable the Port by clear the reset */
> - __afu_port_enable(pdev);
> + /* Enable the Port by clearing the reset */
> + enable_ret = __afu_port_enable(pdev);
>
> done:
> mutex_unlock(&pdata->lock);
> - return ret;
> + return enable_ret ? enable_ret : ret;
Maybe we should add some error message to notify user, there are more errors happened,
as some ret value is not returned.
> }
>
> static ssize_t errors_show(struct device *dev, struct device_attribute *attr,
> diff --git a/drivers/fpga/dfl-afu-main.c b/drivers/fpga/dfl-afu-main.c
> index 753cda4b2568..729eb306062e 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");
Maybe we can change dev_err message in port disable to "disable device" as well. : )
Hao
> + return -ETIMEDOUT;
> + }
> +
> + return 0;
> +}
>
> /**
> * __afu_port_disable - disable a port by hold reset
> @@ -111,9 +124,9 @@ static int __port_reset(struct platform_device *pdev)
>
> ret = __afu_port_disable(pdev);
> if (!ret)
> - __afu_port_enable(pdev);
> + return ret;
>
> - return ret;
> + return __afu_port_enable(pdev);
> }
>
> static int port_reset(struct platform_device *pdev)
> @@ -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);
> --
> 2.25.1
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