Re: [PATCH] Revert "accel/ivpu: Use cached buffers for FW loading"

[Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>]

On Tue, Oct 17, 2023 at 02:13:53PM +0200, Stanislaw Gruszka wrote:
> This reverts commit 645d694559cab36fe6a57c717efcfa27d9321396.
> 
> The commit cause issues with memory access from the device side.
> Switch back to write-combined memory mappings until the issues
> will be properly addressed.
> 
> Add extra wmb() needed when boot_params->save_restore_ret_address() is
> modified.
> 
> Reviewed-by: Karol Wachowski <karol.wachowski@linux.intel.com>
> Signed-off-by: Stanislaw Gruszka <stanislaw.gruszka@linux.intel.com>
Applied to drm-misc-fixes

Thanks
Stanislaw

> ---
>  drivers/accel/ivpu/ivpu_fw.c  | 9 ++++-----
>  drivers/accel/ivpu/ivpu_gem.h | 5 -----
>  2 files changed, 4 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/accel/ivpu/ivpu_fw.c b/drivers/accel/ivpu/ivpu_fw.c
> index 0191cf8e5964..a277bbae78fc 100644
> --- a/drivers/accel/ivpu/ivpu_fw.c
> +++ b/drivers/accel/ivpu/ivpu_fw.c
> @@ -220,8 +220,7 @@ static int ivpu_fw_mem_init(struct ivpu_device *vdev)
>  	if (ret)
>  		return ret;
>  
> -	fw->mem = ivpu_bo_alloc_internal(vdev, fw->runtime_addr, fw->runtime_size,
> -					 DRM_IVPU_BO_CACHED | DRM_IVPU_BO_NOSNOOP);
> +	fw->mem = ivpu_bo_alloc_internal(vdev, fw->runtime_addr, fw->runtime_size, DRM_IVPU_BO_WC);
>  	if (!fw->mem) {
>  		ivpu_err(vdev, "Failed to allocate firmware runtime memory\n");
>  		return -ENOMEM;
> @@ -331,7 +330,7 @@ int ivpu_fw_load(struct ivpu_device *vdev)
>  		memset(start, 0, size);
>  	}
>  
> -	clflush_cache_range(fw->mem->kvaddr, fw->mem->base.size);
> +	wmb(); /* Flush WC buffers after writing fw->mem */
>  
>  	return 0;
>  }
> @@ -433,7 +432,7 @@ void ivpu_fw_boot_params_setup(struct ivpu_device *vdev, struct vpu_boot_params
>  	if (!ivpu_fw_is_cold_boot(vdev)) {
>  		boot_params->save_restore_ret_address = 0;
>  		vdev->pm->is_warmboot = true;
> -		clflush_cache_range(vdev->fw->mem->kvaddr, SZ_4K);
> +		wmb(); /* Flush WC buffers after writing save_restore_ret_address */
>  		return;
>  	}
>  
> @@ -495,7 +494,7 @@ void ivpu_fw_boot_params_setup(struct ivpu_device *vdev, struct vpu_boot_params
>  	boot_params->punit_telemetry_sram_size = ivpu_hw_reg_telemetry_size_get(vdev);
>  	boot_params->vpu_telemetry_enable = ivpu_hw_reg_telemetry_enable_get(vdev);
>  
> -	clflush_cache_range(vdev->fw->mem->kvaddr, SZ_4K);
> +	wmb(); /* Flush WC buffers after writing bootparams */
>  
>  	ivpu_fw_boot_params_print(vdev, boot_params);
>  }
> diff --git a/drivers/accel/ivpu/ivpu_gem.h b/drivers/accel/ivpu/ivpu_gem.h
> index f4130586ff1b..6b0ceda5f253 100644
> --- a/drivers/accel/ivpu/ivpu_gem.h
> +++ b/drivers/accel/ivpu/ivpu_gem.h
> @@ -8,8 +8,6 @@
>  #include <drm/drm_gem.h>
>  #include <drm/drm_mm.h>
>  
> -#define DRM_IVPU_BO_NOSNOOP       0x10000000
> -
>  struct dma_buf;
>  struct ivpu_bo_ops;
>  struct ivpu_file_priv;
> @@ -85,9 +83,6 @@ static inline u32 ivpu_bo_cache_mode(struct ivpu_bo *bo)
>  
>  static inline bool ivpu_bo_is_snooped(struct ivpu_bo *bo)
>  {
> -	if (bo->flags & DRM_IVPU_BO_NOSNOOP)
> -		return false;
> -
>  	return ivpu_bo_cache_mode(bo) == DRM_IVPU_BO_CACHED;
>  }
>  
> -- 
> 2.25.1
>