[Intel-xe] [PATCH 05/12] drm/xe/mmio: Move memory training check to probe vram

[Matt Roper]

On Wed, Nov 08, 2023 at 01:33:37AM +0100, Michał Winiarski wrote:
> The check doesn't have anything to do with initial MMIO setup. Move it
> to the place where it belongs.

Even though it's called "LMEM_INIT," we're supposed to make sure we
don't touch any GT registers until this bit is set (because the GT won't
be fully functional until that point).  It looks like if we move it to
probe_vram, we've already tried to touch GT registers (e.g., under
xe_irq_install) which might cause problems?


Matt

> 
> Signed-off-by: Michał Winiarski <michal.winiarski at intel.com>
> ---
>  drivers/gpu/drm/xe/xe_mmio.c | 24 ++++++++++++------------
>  1 file changed, 12 insertions(+), 12 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
> index 0da4f75c07bf6..f4cddf2dfa3a3 100644
> --- a/drivers/gpu/drm/xe/xe_mmio.c
> +++ b/drivers/gpu/drm/xe/xe_mmio.c
> @@ -254,6 +254,18 @@ int xe_mmio_probe_vram(struct xe_device *xe)
>  
>  	/* Get the size of the root tile's vram for later accessibility comparison */
>  	tile = xe_device_get_root_tile(xe);
> +
> +	/*
> +	 * The boot firmware initializes local memory and assesses its health.
> +	 * If memory training fails, the punit will have been instructed to
> +	 * keep the GT powered down; we won't be able to communicate with it
> +	 * and we should not continue with driver initialization.
> +	 */
> +	if (IS_DGFX(xe) && !(xe_mmio_read32(xe_root_mmio_gt(xe), GU_CNTL) & LMEM_INIT)) {
> +		drm_err(&xe->drm, "VRAM not initialized by firmware\n");
> +		return -ENODEV;
> +	}
> +
>  	err = xe_mmio_tile_vram_size(tile, &vram_size, &tile_size, &tile_offset);
>  	if (err)
>  		return err;
> @@ -384,7 +396,6 @@ static void mmio_fini(struct drm_device *drm, void *arg)
>  int xe_mmio_init(struct xe_device *xe)
>  {
>  	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
> -	struct xe_gt *gt = xe_root_mmio_gt(xe);
>  	const int mmio_bar = 0;
>  	int err;
>  
> @@ -409,17 +420,6 @@ int xe_mmio_init(struct xe_device *xe)
>  	root_tile->mmio.size = xe->mmio.size;
>  	root_tile->mmio.regs = xe->mmio.regs;
>  
> -	/*
> -	 * The boot firmware initializes local memory and assesses its health.
> -	 * If memory training fails, the punit will have been instructed to
> -	 * keep the GT powered down; we won't be able to communicate with it
> -	 * and we should not continue with driver initialization.
> -	 */
> -	if (IS_DGFX(xe) && !(xe_mmio_read32(gt, GU_CNTL) & LMEM_INIT)) {
> -		drm_err(&xe->drm, "VRAM not initialized by firmware\n");
> -		return -ENODEV;
> -	}
> -
>  	err = xe_set_dma_info(xe);
>  	if (err)
>  		return err;
> -- 
> 2.42.0
> 

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