APPLIED: [PATCH][SRU Artful] watchdog: sbsa: use 32-bit read for WCV

[Stefan Bader]

On 13.03.2018 23:51, dann frazier wrote:
> From: Jayachandran C <jnair at caviumnetworks.com>
> 
> BugLink: https://bugs.launchpad.net/bugs/1755595
> 
> According to SBSA spec v3.1 section 5.3:
>   All registers are 32 bits in size and should be accessed using
>   32-bit reads and writes. If an access size other than 32 bits
>   is used then the results are IMPLEMENTATION DEFINED.
>   [...]
>   The Generic Watchdog is little-endian
> 
> The current code uses readq to read the watchdog compare register
> which does a 64-bit access. This fails on ThunderX2 which does not
> implement 64-bit access to this register.
> 
> Fix this by using lo_hi_readq() that does two 32-bit reads.
> 
> Signed-off-by: Jayachandran C <jnair at caviumnetworks.com>
> Reviewed-by: Guenter Roeck <linux at roeck-us.net>
> Signed-off-by: Guenter Roeck <linux at roeck-us.net>
> Signed-off-by: Wim Van Sebroeck <wim at iguana.be>
> (cherry picked from commit 93ac3deb7c220cbcec032a967220a1f109d58431)
> Signed-off-by: dann frazier <dann.frazier at canonical.com>
> ---
>  drivers/watchdog/sbsa_gwdt.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/watchdog/sbsa_gwdt.c b/drivers/watchdog/sbsa_gwdt.c
> index 316c2eb122d2..e8bd9887c566 100644
> --- a/drivers/watchdog/sbsa_gwdt.c
> +++ b/drivers/watchdog/sbsa_gwdt.c
> @@ -50,6 +50,7 @@
>   */
>  
>  #include <linux/io.h>
> +#include <linux/io-64-nonatomic-lo-hi.h>
>  #include <linux/interrupt.h>
>  #include <linux/module.h>
>  #include <linux/moduleparam.h>
> @@ -159,7 +160,7 @@ static unsigned int sbsa_gwdt_get_timeleft(struct watchdog_device *wdd)
>  	    !(readl(gwdt->control_base + SBSA_GWDT_WCS) & SBSA_GWDT_WCS_WS0))
>  		timeleft += readl(gwdt->control_base + SBSA_GWDT_WOR);
>  
> -	timeleft += readq(gwdt->control_base + SBSA_GWDT_WCV) -
> +	timeleft += lo_hi_readq(gwdt->control_base + SBSA_GWDT_WCV) -
>  		    arch_counter_get_cntvct();
>  
>  	do_div(timeleft, gwdt->clk);
> 

Applied to artful master-next

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