[PATCH] drm/xe/xe3: Extend wa_15015404425 for xe3

[Matt Roper]

On Tue, Jan 28, 2025 at 04:55:51PM -0800, Matt Atwood wrote:
> From: Tejas Upadhyay <tejas.upadhyay at intel.com>
> 
> wa_15015404425 applies to xe3 A0 step as well.

We really need a better commit message explaining how this workaround is
different from our usual ones and why it needs to be handled in a
special way that's different from all of our other workarounds,
especially since someone who just quickly skims the workaround database
without digging into the details is going to incorrectly think this just
applies to Xe2 media and isn't relevant to PTL.

I was kind of hoping we'd add a more well-defined infrastructure for
handling device / SoC workarounds.  Adding quick hacks like this is
going to get out of hand quickly if more of these start showing up.


Matt

> 
> v2: query based off SOC stepping
> 
> Signed-off-by: Tejas Upadhyay <tejas.upadhyay at intel.com>
> Signed-off-by: Matt Atwood <matthew.s.atwood at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_mmio.c | 13 +++++++------
>  drivers/gpu/drm/xe/xe_step.h |  2 ++
>  2 files changed, 9 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
> index d321a21aacf0..98d068ad33bb 100644
> --- a/drivers/gpu/drm/xe/xe_mmio.c
> +++ b/drivers/gpu/drm/xe/xe_mmio.c
> @@ -150,14 +150,15 @@ int xe_mmio_init(struct xe_device *xe)
>  static void mmio_flush_pending_writes(struct xe_mmio *mmio)
>  {
>  #define DUMMY_REG_OFFSET	0x130030
> +	struct xe_device *xe = tile_to_xe(mmio->tile);
>  	int i;
>  
> -	if (mmio->tile->xe->info.platform != XE_LUNARLAKE)
> -		return;
> -
> -	/* 4 dummy writes */
> -	for (i = 0; i < 4; i++)
> -		writel(0, mmio->regs + DUMMY_REG_OFFSET);
> +	if (xe->info.platform == XE_LUNARLAKE ||
> +	    (xe->info.platform == XE_PANTHERLAKE &&
> +	     xe->info.revid == PTL_SOC_STEP_A0))
> +		/* 4 dummy writes */
> +		for (i = 0; i < 4; i++)
> +			writel(0, mmio->regs + DUMMY_REG_OFFSET);
>  }
>  
>  u8 xe_mmio_read8(struct xe_mmio *mmio, struct xe_reg reg)
> diff --git a/drivers/gpu/drm/xe/xe_step.h b/drivers/gpu/drm/xe/xe_step.h
> index 686cb59200c2..879486a818e9 100644
> --- a/drivers/gpu/drm/xe/xe_step.h
> +++ b/drivers/gpu/drm/xe/xe_step.h
> @@ -20,4 +20,6 @@ static inline u32 xe_step_to_gmdid(enum xe_step step) { return step - STEP_A0; }
>  
>  const char *xe_step_name(enum xe_step step);
>  
> +#define PTL_SOC_STEP_A0  0x0
> +
>  #endif
> -- 
> 2.45.0
> 

-- 
Matt Roper
Graphics Software Engineer
Linux GPU Platform Enablement
Intel Corporation