[PATCH] drm/xe/xe3: Generate and store the L3 bank mask

[Matt Roper]

On Tue, Jan 14, 2025 at 12:38:53PM -0800, Matt Atwood wrote:
> From: Francois Dugast <francois.dugast at intel.com>
> 
> On Xe3, the register used to indicate which L3 banks are enabled on
> the system is a new one called MIRROR_L3BANK_ENABLE. Each bit
> represents one bank enabled in each node.
> Extend the existing topology code for Xe3 to read this register and
> generate the correct L3 bank mask, which can be read by user space
> throug the topology query.
> 
> Bspec: 72573, 73439
> Signed-off-by: Francois Dugast <francois.dugast at intel.com>
> Signed-off-by: Matt Atwood <matthew.s.atwood at intel.com>
> ---
>  drivers/gpu/drm/xe/regs/xe_gt_regs.h |  3 +++
>  drivers/gpu/drm/xe/xe_gt_topology.c  | 16 +++++++++++++---
>  2 files changed, 16 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/gpu/drm/xe/regs/xe_gt_regs.h b/drivers/gpu/drm/xe/regs/xe_gt_regs.h
> index b4283ac030f4..096859072396 100644
> --- a/drivers/gpu/drm/xe/regs/xe_gt_regs.h
> +++ b/drivers/gpu/drm/xe/regs/xe_gt_regs.h
> @@ -221,6 +221,9 @@
>  
>  #define MIRROR_FUSE1				XE_REG(0x911c)
>  
> +#define MIRROR_L3BANK_ENABLE			XE_REG(0x9130)
> +#define   XE3_L3BANK_ENABLE			REG_GENMASK(31, 0)
> +
>  #define XELP_EU_ENABLE				XE_REG(0x9134)	/* "_DISABLE" on Xe_LP */
>  #define   XELP_EU_MASK				REG_GENMASK(7, 0)
>  #define XELP_GT_SLICE_ENABLE			XE_REG(0x9138)
> diff --git a/drivers/gpu/drm/xe/xe_gt_topology.c b/drivers/gpu/drm/xe/xe_gt_topology.c
> index df2042db7ee6..516c81e3b8dd 100644
> --- a/drivers/gpu/drm/xe/xe_gt_topology.c
> +++ b/drivers/gpu/drm/xe/xe_gt_topology.c
> @@ -129,7 +129,8 @@ static void
>  load_l3_bank_mask(struct xe_gt *gt, xe_l3_bank_mask_t l3_bank_mask)
>  {
>  	struct xe_device *xe = gt_to_xe(gt);
> -	u32 fuse3 = xe_mmio_read32(&gt->mmio, MIRROR_FUSE3);
> +	struct xe_mmio *mmio = &gt->mmio;
> +	u32 fuse3 = xe_mmio_read32(mmio, MIRROR_FUSE3);
>  
>  	/*
>  	 * PTL platforms with media version 30.00 do not provide proper values
> @@ -143,7 +144,16 @@ load_l3_bank_mask(struct xe_gt *gt, xe_l3_bank_mask_t l3_bank_mask)
>  	if (XE_WA(gt, no_media_l3))
>  		return;
>  
> -	if (GRAPHICS_VER(xe) >= 20) {
> +	if (GRAPHICS_VER(xe) >= 30) {
> +		xe_l3_bank_mask_t per_node = {};
> +		u32 meml3_en = REG_FIELD_GET(XE2_NODE_ENABLE_MASK, fuse3);
> +		u32 mirror_l3bank_enable = xe_mmio_read32(mmio, MIRROR_L3BANK_ENABLE);
> +		u32 bank_val = REG_FIELD_GET(XE3_L3BANK_ENABLE, mirror_l3bank_enable);
> +
> +		bitmap_from_arr32(per_node, &bank_val, 32);

Doesn't each bit in L3BANK_ENABLE represent a pair of banks rather than
a single bank?  It doesn't look like that's accounted for here.


Matt

> +		gen_l3_mask_from_pattern(xe, l3_bank_mask, per_node, 32,
> +					 meml3_en);
> +	} else if (GRAPHICS_VER(xe) >= 20) {
>  		xe_l3_bank_mask_t per_node = {};
>  		u32 meml3_en = REG_FIELD_GET(XE2_NODE_ENABLE_MASK, fuse3);
>  		u32 bank_val = REG_FIELD_GET(XE2_GT_L3_MODE_MASK, fuse3);
> @@ -155,7 +165,7 @@ load_l3_bank_mask(struct xe_gt *gt, xe_l3_bank_mask_t l3_bank_mask)
>  		xe_l3_bank_mask_t per_node = {};
>  		xe_l3_bank_mask_t per_mask_bit = {};
>  		u32 meml3_en = REG_FIELD_GET(MEML3_EN_MASK, fuse3);
> -		u32 fuse4 = xe_mmio_read32(&gt->mmio, XEHP_FUSE4);
> +		u32 fuse4 = xe_mmio_read32(mmio, XEHP_FUSE4);
>  		u32 bank_val = REG_FIELD_GET(GT_L3_EXC_MASK, fuse4);
>  
>  		bitmap_set_value8(per_mask_bit, 0x3, 0);
> -- 
> 2.45.0
> 

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