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Message-ID: <YFuClO0wzhA89WOX@epycbox.lan>
Date: Wed, 24 Mar 2021 11:19:00 -0700
From: Moritz Fischer <mdf@...nel.org>
To: Russ Weight <russell.h.weight@...el.com>
Cc: mdf@...nel.org, linux-fpga@...r.kernel.org,
linux-kernel@...r.kernel.org, trix@...hat.com, lgoncalv@...hat.com,
yilun.xu@...el.com, hao.wu@...el.com, matthew.gerlach@...el.com,
Matthew Gerlach <matthew.gerlach@...ux.intel.com>
Subject: Re: [PATCH v9 1/1] fpga: dfl: afu: harden port enable logic
On Tue, Mar 23, 2021 at 03:46:50PM -0700, Russ Weight wrote:
> 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>
> Reviewed-by: Tom Rix <trix@...hat.com>
> Reviewed-by: Matthew Gerlach <matthew.gerlach@...ux.intel.com>
> Acked-by: Wu Hao <hao.wu@...el.com>
> ---
> v9:
> - Fix the sense of the if condition in __port_reset()
> v8:
> - Rebased to 5.12-rc1 (there were no conflicts)
> v7:
> - Added Acked-by tag from Wu Hao
> v6:
> - Fixed the dev_warn statement, which had "__func__" embedded in the
> string instead of treated as a parameter to the format string.
> v5:
> - Added Reviewed-by tag to commit message
> v4:
> - Added a dev_warn() call for the -EINVAL case of afu_port_err_clear()
> - Modified dev_err() message in __afu_port_disable() to say "disable"
> instead of "reset"
> 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 | 10 ++++++----
> drivers/fpga/dfl-afu-main.c | 35 ++++++++++++++++++++++++-----------
> drivers/fpga/dfl-afu.h | 2 +-
> 3 files changed, 31 insertions(+), 16 deletions(-)
>
> diff --git a/drivers/fpga/dfl-afu-error.c b/drivers/fpga/dfl-afu-error.c
> index c4691187cca9..ab7be6217368 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);
> @@ -96,18 +96,20 @@ static int afu_port_err_clear(struct device *dev, u64 err)
> v = readq(base_err + PORT_FIRST_ERROR);
> writeq(v, base_err + PORT_FIRST_ERROR);
> } else {
> + dev_warn(dev, "%s: received 0x%llx, expected 0x%llx\n",
> + __func__, v, err);
> ret = -EINVAL;
> }
>
> /* 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;
> }
>
> 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..7f621e96d3b8 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
> @@ -86,7 +99,7 @@ int __afu_port_disable(struct platform_device *pdev)
> 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, fail to reset device\n");
> + dev_err(&pdev->dev, "timeout, failure to disable device\n");
> return -ETIMEDOUT;
> }
>
> @@ -110,10 +123,10 @@ static int __port_reset(struct platform_device *pdev)
> int ret;
>
> ret = __afu_port_disable(pdev);
> - if (!ret)
> - __afu_port_enable(pdev);
> + if (ret)
> + 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
>
Applied to for-next.
Thanks,
Moritz
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