Re: [PATCH 3/9] drm/xe: Add functions to convert regular address to canonical address and back

["Summers, Stuart" <stuart.summers@intel.com>]

On Mon, 2024-01-22 at 09:04 -0800, José Roberto de Souza wrote:
> Some instructions requires canonical address like
> MI_BATCH_BUFFER_START(UMDs must call xe_exec with a canonical address
> for Xe2+).
> 
> So here adding functions to convert regular address to canonical
> address and back, the first user of this functions will be added
> in the next patches.
> 
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Maarten Lankhorst <dev@lankhorst.se>
> Signed-off-by: José Roberto de Souza <jose.souza@intel.com>
> ---
>  drivers/gpu/drm/xe/xe_device.c | 15 +++++++++++++++
>  drivers/gpu/drm/xe/xe_device.h |  3 +++
>  2 files changed, 18 insertions(+)
> 
> diff --git a/drivers/gpu/drm/xe/xe_device.c
> b/drivers/gpu/drm/xe/xe_device.c
> index ab417f4f7d2a7..b4cdcf1b2081a 100644
> --- a/drivers/gpu/drm/xe/xe_device.c
> +++ b/drivers/gpu/drm/xe/xe_device.c
> @@ -727,3 +727,18 @@ void xe_device_mem_access_put(struct xe_device
> *xe)
>  
>         xe_assert(xe, ref >= 0);
>  }
> +
> +static inline int highest_address_bit_get(struct xe_device *xe)
> +{
> +       return xe->info.dma_mask_size > 48 ? 57 : 47;

Why not just xe->info.dma_mask_size - 1?

Thanks,
Stuart

> +}
> +
> +u64 xe_device_canonicalize_addr(struct xe_device *xe, u64 address)
> +{
> +       return sign_extend64(address, highest_address_bit_get(xe));
> +}
> +
> +u64 xe_device_uncanonicalize_addr(struct xe_device *xe, u64 address)
> +{
> +       return address & GENMASK_ULL(highest_address_bit_get(xe), 0);
> +}
> diff --git a/drivers/gpu/drm/xe/xe_device.h
> b/drivers/gpu/drm/xe/xe_device.h
> index af8ac2e9e2709..ce20f6fe6219a 100644
> --- a/drivers/gpu/drm/xe/xe_device.h
> +++ b/drivers/gpu/drm/xe/xe_device.h
> @@ -175,4 +175,7 @@ static inline bool xe_device_has_memirq(struct
> xe_device *xe)
>  
>  u32 xe_device_ccs_bytes(struct xe_device *xe, u64 size);
>  
> +u64 xe_device_canonicalize_addr(struct xe_device *xe, u64 address);
> +u64 xe_device_uncanonicalize_addr(struct xe_device *xe, u64
> address);
> +
>  #endif