[PATCH] drm/amdgpu: simplify allocation of scratch regs

[Christian König]

Am 16.01.2017 um 21:56 schrieb Nils Wallménius:
> The scratch regs are sequential so there's no need to keep
> them in an array, we can just return the index of the first
> free register + the base register. Also change the array
> of bools for keeping track of the free regs to a bitfield.
>
> Signed-off-by: Nils Wallménius <nils.wallmenius at gmail.com>

Reviewed-by: Christian König <christian.koenig at amd.com>.

> ---
>   drivers/gpu/drm/amd/amdgpu/amdgpu.h     |  3 +--
>   drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c | 21 +++++++--------------
>   drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c   |  7 +------
>   drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c   |  7 +------
>   drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c   |  7 +------
>   5 files changed, 11 insertions(+), 34 deletions(-)
>
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu.h b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> index ffeda245..9531480 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu.h
> @@ -794,8 +794,7 @@ struct amdgpu_kiq {
>   struct amdgpu_scratch {
>   	unsigned		num_reg;
>   	uint32_t                reg_base;
> -	bool			free[32];
> -	uint32_t		reg[32];
> +	uint32_t		free_mask;
>   };
>   
>   /*
> diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
> index 01a42b6..1994335 100644
> --- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
> +++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
> @@ -42,12 +42,12 @@ int amdgpu_gfx_scratch_get(struct amdgpu_device *adev, uint32_t *reg)
>   {
>   	int i;
>   
> -	for (i = 0; i < adev->gfx.scratch.num_reg; i++) {
> -		if (adev->gfx.scratch.free[i]) {
> -			adev->gfx.scratch.free[i] = false;
> -			*reg = adev->gfx.scratch.reg[i];
> -			return 0;
> -		}
> +	i = ffs(adev->gfx.scratch.free_mask);
> +	if (i != 0 && i <= adev->gfx.scratch.num_reg) {
> +		i--;
> +		adev->gfx.scratch.free_mask &= ~(1u << i);
> +		*reg = adev->gfx.scratch.reg_base + i;
> +		return 0;
>   	}
>   	return -EINVAL;
>   }
> @@ -62,14 +62,7 @@ int amdgpu_gfx_scratch_get(struct amdgpu_device *adev, uint32_t *reg)
>    */
>   void amdgpu_gfx_scratch_free(struct amdgpu_device *adev, uint32_t reg)
>   {
> -	int i;
> -
> -	for (i = 0; i < adev->gfx.scratch.num_reg; i++) {
> -		if (adev->gfx.scratch.reg[i] == reg) {
> -			adev->gfx.scratch.free[i] = true;
> -			return;
> -		}
> -	}
> +	adev->gfx.scratch.free_mask |= 1u << (reg - adev->gfx.scratch.reg_base);
>   }
>   
>   /**
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c
> index b323f5e..e013243 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v6_0.c
> @@ -1794,14 +1794,9 @@ static void gfx_v6_0_gpu_init(struct amdgpu_device *adev)
>   
>   static void gfx_v6_0_scratch_init(struct amdgpu_device *adev)
>   {
> -	int i;
> -
>   	adev->gfx.scratch.num_reg = 7;
>   	adev->gfx.scratch.reg_base = mmSCRATCH_REG0;
> -	for (i = 0; i < adev->gfx.scratch.num_reg; i++) {
> -		adev->gfx.scratch.free[i] = true;
> -		adev->gfx.scratch.reg[i] = adev->gfx.scratch.reg_base + i;
> -	}
> +	adev->gfx.scratch.free_mask = (1u << adev->gfx.scratch.num_reg) - 1;
>   }
>   
>   static int gfx_v6_0_ring_test_ring(struct amdgpu_ring *ring)
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c
> index c4e1401..cfed6db 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v7_0.c
> @@ -2003,14 +2003,9 @@ static void gfx_v7_0_gpu_init(struct amdgpu_device *adev)
>    */
>   static void gfx_v7_0_scratch_init(struct amdgpu_device *adev)
>   {
> -	int i;
> -
>   	adev->gfx.scratch.num_reg = 7;
>   	adev->gfx.scratch.reg_base = mmSCRATCH_REG0;
> -	for (i = 0; i < adev->gfx.scratch.num_reg; i++) {
> -		adev->gfx.scratch.free[i] = true;
> -		adev->gfx.scratch.reg[i] = adev->gfx.scratch.reg_base + i;
> -	}
> +	adev->gfx.scratch.free_mask = (1u << adev->gfx.scratch.num_reg) - 1;
>   }
>   
>   /**
> diff --git a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
> index c8c45ba..69543d4 100644
> --- a/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
> +++ b/drivers/gpu/drm/amd/amdgpu/gfx_v8_0.c
> @@ -749,14 +749,9 @@ static void gfx_v8_0_init_golden_registers(struct amdgpu_device *adev)
>   
>   static void gfx_v8_0_scratch_init(struct amdgpu_device *adev)
>   {
> -	int i;
> -
>   	adev->gfx.scratch.num_reg = 7;
>   	adev->gfx.scratch.reg_base = mmSCRATCH_REG0;
> -	for (i = 0; i < adev->gfx.scratch.num_reg; i++) {
> -		adev->gfx.scratch.free[i] = true;
> -		adev->gfx.scratch.reg[i] = adev->gfx.scratch.reg_base + i;
> -	}
> +	adev->gfx.scratch.free_mask = (1u << adev->gfx.scratch.num_reg) - 1;
>   }
>   
>   static int gfx_v8_0_ring_test_ring(struct amdgpu_ring *ring)