linux-kernel - Re: [PATCH net-next v2] net: ethernet: ti: am65-cpsw/cpts: Fix CPTS release action

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Message-ID: <Y8T8+rWrvv6gfNxa@unreal>
Date:   Mon, 16 Jan 2023 09:30:02 +0200
From:   Leon Romanovsky <leon@...nel.org>
To:     Siddharth Vadapalli <s-vadapalli@...com>
Cc:     davem@...emloft.net, edumazet@...gle.com, kuba@...nel.org,
        linux@...linux.org.uk, pabeni@...hat.com, rogerq@...nel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, vigneshr@...com, srk@...com
Subject: Re: [PATCH net-next v2] net: ethernet: ti: am65-cpsw/cpts: Fix CPTS
 release action

On Mon, Jan 16, 2023 at 10:15:17AM +0530, Siddharth Vadapalli wrote:
> The am65_cpts_release() function is registered as a devm_action in the
> am65_cpts_create() function in am65-cpts driver. When the am65-cpsw driver
> invokes am65_cpts_create(), am65_cpts_release() is added in the set of devm
> actions associated with the am65-cpsw driver's device.
> 
> In the event of probe failure or probe deferral, the platform_drv_probe()
> function invokes dev_pm_domain_detach() which powers off the CPSW and the
> CPSW's CPTS hardware, both of which share the same power domain. Since the
> am65_cpts_disable() function invoked by the am65_cpts_release() function
> attempts to reset the CPTS hardware by writing to its registers, the CPTS
> hardware is assumed to be powered on at this point. However, the hardware
> is powered off before the devm actions are executed.
> 
> Fix this by getting rid of the devm action for am65_cpts_release() and
> invoking it directly on the cleanup and exit paths.
> 
> Fixes: f6bd59526ca5 ("net: ethernet: ti: introduce am654 common platform time sync driver")
> Signed-off-by: Siddharth Vadapalli <s-vadapalli@...com>
> Reviewed-by: Roger Quadros <rogerq@...nel.org>
> ---
> Changes from v1:
> 1. Fix the build issue when "CONFIG_TI_K3_AM65_CPTS" is not set. This
>    error was reported by kernel test robot <lkp@...el.com> at:
>    https://lore.kernel.org/r/202301142105.lt733Lt3-lkp@intel.com/
> 2. Collect Reviewed-by tag from Roger Quadros.
> 
> v1:
> https://lore.kernel.org/r/20230113104816.132815-1-s-vadapalli@ti.com/
> 
>  drivers/net/ethernet/ti/am65-cpsw-nuss.c |  8 ++++++++
>  drivers/net/ethernet/ti/am65-cpts.c      | 15 +++++----------
>  drivers/net/ethernet/ti/am65-cpts.h      |  5 +++++
>  3 files changed, 18 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/net/ethernet/ti/am65-cpsw-nuss.c b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> index 5cac98284184..00f25d8a026b 100644
> --- a/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> +++ b/drivers/net/ethernet/ti/am65-cpsw-nuss.c
> @@ -1913,6 +1913,12 @@ static int am65_cpsw_am654_get_efuse_macid(struct device_node *of_node,
>  	return 0;
>  }
>  
> +static void am65_cpsw_cpts_cleanup(struct am65_cpsw_common *common)
> +{
> +	if (IS_ENABLED(CONFIG_TI_K3_AM65_CPTS) && common->cpts)

Why do you have IS_ENABLED(CONFIG_TI_K3_AM65_CPTS), if
am65_cpts_release() defined as empty when CONFIG_TI_K3_AM65_CPTS not set?

How is it possible to have common->cpts == NULL?

And why do you need special am65_cpsw_cpts_cleanup() which does nothing
except call to am65_cpts_release()? It will be more intuitive change
the latter to be exported function.

Thanks