[PATCH 1/3] drm/xe: Separate pure MMIO init from VRAM checkout

[Matt Roper]

On Wed, Mar 27, 2024 at 07:27:38PM +0100, Michal Wajdeczko wrote:
> We can setup root tile registers mapping at the same time as we
> do early mapping of the entire MMIO BAR and keep mandatory VRAM
> checkout as a separate step. This will allow us to perform SR-IOV
> VF mode detection between those two steps using regular MMIO regs
> access functions.
> 
> Signed-off-by: Michal Wajdeczko <michal.wajdeczko at intel.com>
> Cc: Matt Roper <matthew.d.roper at intel.com>

Reviewed-by: Matt Roper <matthew.d.roper at intel.com>

> ---
>  drivers/gpu/drm/xe/xe_device.c |  2 +-
>  drivers/gpu/drm/xe/xe_mmio.c   | 59 ++++++++++++++--------------------
>  drivers/gpu/drm/xe/xe_mmio.h   |  2 +-
>  3 files changed, 26 insertions(+), 37 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/xe_device.c b/drivers/gpu/drm/xe/xe_device.c
> index b0bfe75eb59f..286ebccc3fc8 100644
> --- a/drivers/gpu/drm/xe/xe_device.c
> +++ b/drivers/gpu/drm/xe/xe_device.c
> @@ -424,7 +424,7 @@ int xe_device_probe_early(struct xe_device *xe)
>  	if (err)
>  		return err;
>  
> -	err = xe_mmio_root_tile_init(xe);
> +	err = xe_mmio_verify_vram(xe);
>  	if (err)
>  		return err;
>  
> diff --git a/drivers/gpu/drm/xe/xe_mmio.c b/drivers/gpu/drm/xe/xe_mmio.c
> index 1de9de4f94b6..5d13fc7cb9d2 100644
> --- a/drivers/gpu/drm/xe/xe_mmio.c
> +++ b/drivers/gpu/drm/xe/xe_mmio.c
> @@ -360,32 +360,9 @@ static void mmio_fini(struct drm_device *drm, void *arg)
>  		iounmap(xe->mem.vram.mapping);
>  }
>  
> -static int xe_verify_lmem_ready(struct xe_device *xe)
> -{
> -	struct xe_gt *gt = xe_root_mmio_gt(xe);
> -
> -	if (!IS_DGFX(xe))
> -		return 0;
> -
> -	if (IS_SRIOV_VF(xe))
> -		return 0;
> -
> -	/*
> -	 * 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 (!(xe_mmio_read32(gt, GU_CNTL) & LMEM_INIT)) {
> -		drm_err(&xe->drm, "VRAM not initialized by firmware\n");
> -		return -ENODEV;
> -	}
> -
> -	return 0;
> -}
> -
>  int xe_mmio_init(struct xe_device *xe)
>  {
> +	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
>  	struct pci_dev *pdev = to_pci_dev(xe->drm.dev);
>  	const int mmio_bar = 0;
>  
> @@ -401,21 +378,33 @@ int xe_mmio_init(struct xe_device *xe)
>  		return -EIO;
>  	}
>  
> -	return drmm_add_action_or_reset(&xe->drm, mmio_fini, xe);
> -}
> -
> -int xe_mmio_root_tile_init(struct xe_device *xe)
> -{
> -	struct xe_tile *root_tile = xe_device_get_root_tile(xe);
> -	int err;
> -
>  	/* Setup first tile; other tiles (if present) will be setup later. */
>  	root_tile->mmio.size = SZ_16M;
>  	root_tile->mmio.regs = xe->mmio.regs;
>  
> -	err = xe_verify_lmem_ready(xe);
> -	if (err)
> -		return err;
> +	return drmm_add_action_or_reset(&xe->drm, mmio_fini, xe);
> +}
> +
> +int xe_mmio_verify_vram(struct xe_device *xe)
> +{
> +	struct xe_gt *gt = xe_root_mmio_gt(xe);
> +
> +	if (!IS_DGFX(xe))
> +		return 0;
> +
> +	if (IS_SRIOV_VF(xe))
> +		return 0;
> +
> +	/*
> +	 * 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 (!(xe_mmio_read32(gt, GU_CNTL) & LMEM_INIT)) {
> +		drm_err(&xe->drm, "VRAM not initialized by firmware\n");
> +		return -ENODEV;
> +	}
>  
>  	return 0;
>  }
> diff --git a/drivers/gpu/drm/xe/xe_mmio.h b/drivers/gpu/drm/xe/xe_mmio.h
> index 67ead99f321b..b1680c4a14fb 100644
> --- a/drivers/gpu/drm/xe/xe_mmio.h
> +++ b/drivers/gpu/drm/xe/xe_mmio.h
> @@ -21,7 +21,7 @@ struct xe_device;
>  #define LMEM_BAR		2
>  
>  int xe_mmio_init(struct xe_device *xe);
> -int xe_mmio_root_tile_init(struct xe_device *xe);
> +int xe_mmio_verify_vram(struct xe_device *xe);
>  void xe_mmio_probe_tiles(struct xe_device *xe);
>  
>  u8 xe_mmio_read8(struct xe_gt *gt, struct xe_reg reg);
> -- 
> 2.43.0
> 

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