drm/xe: Remove unused "mmio_ext" code

The "mmio_ext" and 'REG_EXT" code is currently unused on any existing
platform.  Going forward, this also isn't the design we want to use for
any future platforms/features either, so we should just go ahead and
remove the dead code to avoid confusion.

mmio_ext was originally added in an attempt to hack around the early
(mis)design of the Xe driver, which used xe_gt as the target for all
register MMIO access, even those completely unrelated to the GT subunit
of the hardware.  With the introduction of commit 34953ee3 ("drm/xe:
Create dedicated xe_mmio structure") and its follow-up patches, that
misdesign has been corrected and access to register MMIO regions
specific to hardware units is now done through xe_mmio structures which
encapsulate an iomap, region size, and some other metadata.

Although all of the registers used by the driver today happen to fall
within one specific PCI BAR region, and thus re-use a single device-wide
iomap, there's no requirement that this stay true for future platforms
or features.  I.e., if a future platform adds a new 'foo' hardware unit
that exists at a different area in the BAR, or even in a completely
different BAR, then that would be handled by doing a separate iomap of
that unit's register region and wrapping it in its own 'struct xe_mmio
foo_regs' structure.  The pointer to the new 'foo_regs' could be placed
within the xe_device, xe_tile, xe_gt, etc., according to where the new
hardware unit falls within the current hardware hierarchy.

This effectively reverts the following commits, although parts of these
commits had already vanished or changed with the earlier xe_mmio
refactor work:

 - commit 399a1332 ("drm/xe: add 28-bit address support in struct
   xe_reg")
 - commit fdef72e0 ("drm/xe: add a flag to bypass multi-tile config
   from MTCFG reg")
 - commit 866b2b17 ("drm/xe: add MMIO extension support flags")
 - commit ef29b390 ("drm/xe: map MMIO BAR according to the num of
   tiles in device desc")
 - commit a4e2f3a2 ("drm/xe: refactor xe_mmio_probe_tiles to support
   MMIO extension")

Cc: Lucas De Marchi <lucas.demarchi@intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Koby Elbaz <kelbaz@habana.ai>
Acked-by: Maciej Patelczyk <maciej.patelczyk@intel.com>
Reviewed-by: Reviewed-by: Lucas De Marchi <lucas.demarchi@intel.com>
Reviewed-by: Stuart Summers <stuart.summers@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20250106234312.2986065-2-matthew.d.roper@intel.com


Signed-off-by: Matt Roper <matthew.d.roper@intel.com>

drivers/gpu/drm/xe/regs/xe_reg_defs.h

@@ -21,7 +21,7 @@ struct xe_reg {
 	union {
 		struct {
 			/** @addr: address */
-			u32 addr:28;
+			u32 addr:22;
 			/**
 			 * @masked: register is "masked", with upper 16bits used
 			 * to identify the bits that are updated on the lower
@@ -41,10 +41,6 @@ struct xe_reg {
 			 * @vf: register is accessible from the Virtual Function.
 			 */
 			u32 vf:1;
-			/**
-			 * @ext: access MMIO extension space for current register.
-			 */
-			u32 ext:1;
 		};
 		/** @raw: Raw value with both address and options */
 		u32 raw;
@@ -111,16 +107,6 @@ struct xe_reg_mcr {
  */
 #define XE_REG(r_, ...)		((const struct xe_reg)XE_REG_INITIALIZER(r_, ##__VA_ARGS__))
 
-/**
- * XE_REG_EXT - Create a struct xe_reg from extension offset and additional
- * flags
- * @r_: Register extension offset
- * @...: Additional options like access mode. See struct xe_reg for available
- *       options.
- */
-#define XE_REG_EXT(r_, ...)	\
-	((const struct xe_reg)XE_REG_INITIALIZER(r_, ##__VA_ARGS__, .ext = 1))
-
 /**
  * XE_REG_MCR - Create a struct xe_reg_mcr from offset and additional flags
  * @r_: Register offset

drivers/gpu/drm/xe/xe_device_types.h

@@ -186,13 +186,6 @@ struct xe_tile {
 	 */
 	struct xe_mmio mmio;
 
-	/**
-	 * @mmio_ext: MMIO-extension info for a tile.
-	 *
-	 * Each tile has its own additional 256MB (28-bit) MMIO-extension space.
-	 */
-	struct xe_mmio mmio_ext;
-
 	/** @mem: memory management info for tile */
 	struct {
 		/**
@@ -263,8 +256,6 @@ struct xe_device {
 		const char *graphics_name;
 		/** @info.media_name: media IP name */
 		const char *media_name;
-		/** @info.tile_mmio_ext_size: size of MMIO extension space, per-tile */
-		u32 tile_mmio_ext_size;
 		/** @info.graphics_verx100: graphics IP version */
 		u32 graphics_verx100;
 		/** @info.media_verx100: media IP version */
@@ -314,8 +305,6 @@ struct xe_device {
 		u8 has_heci_gscfi:1;
 		/** @info.has_llc: Device has a shared CPU+GPU last level cache */
 		u8 has_llc:1;
-		/** @info.has_mmio_ext: Device has extra MMIO address range */
-		u8 has_mmio_ext:1;
 		/** @info.has_range_tlb_invalidation: Has range based TLB invalidations */
 		u8 has_range_tlb_invalidation:1;
 		/** @info.has_sriov: Supports SR-IOV */

drivers/gpu/drm/xe/xe_mmio.c

@@ -103,50 +103,11 @@ static void mmio_multi_tile_setup(struct xe_device *xe, size_t tile_mmio_size)
 	}
 }
 
-/*
- * On top of all the multi-tile MMIO space there can be a platform-dependent
- * extension for each tile, resulting in a layout like below:
- *
- * .----------------------. <- ext_base + tile_count * tile_mmio_ext_size
- * |         ....         |
- * |----------------------| <- ext_base + 2 * tile_mmio_ext_size
- * | tile1->mmio_ext.regs |
- * |----------------------| <- ext_base + 1 * tile_mmio_ext_size
- * | tile0->mmio_ext.regs |
- * |======================| <- ext_base = tile_count * tile_mmio_size
- * |                      |
- * |       mmio.regs      |
- * |                      |
- * '----------------------' <- 0MB
- *
- * Set up the tile[]->mmio_ext pointers/sizes.
- */
-static void mmio_extension_setup(struct xe_device *xe, size_t tile_mmio_size,
-				 size_t tile_mmio_ext_size)
-{
-	struct xe_tile *tile;
-	void __iomem *regs;
-	u8 id;
-
-	if (!xe->info.has_mmio_ext)
-		return;
-
-	regs = xe->mmio.regs + tile_mmio_size * xe->info.tile_count;
-	for_each_tile(tile, xe, id) {
-		tile->mmio_ext.regs_size = tile_mmio_ext_size;
-		tile->mmio_ext.regs = regs;
-		tile->mmio_ext.tile = tile;
-		regs += tile_mmio_ext_size;
-	}
-}
-
 int xe_mmio_probe_tiles(struct xe_device *xe)
 {
 	size_t tile_mmio_size = SZ_16M;
-	size_t tile_mmio_ext_size = xe->info.tile_mmio_ext_size;
 
 	mmio_multi_tile_setup(xe, tile_mmio_size);
-	mmio_extension_setup(xe, tile_mmio_size, tile_mmio_ext_size);
 
 	return devm_add_action_or_reset(xe->drm.dev, tiles_fini, xe);
 }

drivers/gpu/drm/xe/xe_pci.c

@@ -61,7 +61,6 @@ struct xe_device_desc {
 	u8 has_heci_gscfi:1;
 	u8 has_heci_cscfi:1;
 	u8 has_llc:1;
-	u8 has_mmio_ext:1;
 	u8 has_sriov:1;
 	u8 skip_guc_pc:1;
 	u8 skip_mtcfg:1;
@@ -617,7 +616,6 @@ static int xe_info_init_early(struct xe_device *xe,
 	xe->info.has_heci_gscfi = desc->has_heci_gscfi;
 	xe->info.has_heci_cscfi = desc->has_heci_cscfi;
 	xe->info.has_llc = desc->has_llc;
-	xe->info.has_mmio_ext = desc->has_mmio_ext;
 	xe->info.has_sriov = desc->has_sriov;
 	xe->info.skip_guc_pc = desc->skip_guc_pc;
 	xe->info.skip_mtcfg = desc->skip_mtcfg;
@@ -677,7 +675,6 @@ static int xe_info_init(struct xe_device *xe,
 
 	xe->info.graphics_name = graphics_desc->name;
 	xe->info.media_name = media_desc ? media_desc->name : "none";
-	xe->info.tile_mmio_ext_size = graphics_desc->tile_mmio_ext_size;
 
 	xe->info.dma_mask_size = graphics_desc->dma_mask_size;
 	xe->info.vram_flags = graphics_desc->vram_flags;

drivers/gpu/drm/xe/xe_pci_types.h

@@ -20,8 +20,6 @@ struct xe_graphics_desc {
 
 	u64 hw_engine_mask;	/* hardware engines provided by graphics IP */
 
-	u32 tile_mmio_ext_size; /* size of MMIO extension space, per-tile */
-
 	u8 max_remote_tiles:2;
 
 	u8 has_asid:1;