[PATCH 3/3] drm/imagination: Size page table preallocation by device address

[Gyeyoung Baek]

pvr_mmu_op_context_create() preallocates the page tables a mapping
needs. How many is set by the device-virtual address being mapped, not
by the offset into the object's pages, which it used instead.

Size the preallocation from the device address instead.

Fixes: ff5f643de0bf ("drm/imagination: Add GEM and VM related code")
Signed-off-by: Gyeyoung Baek <gye976@xxxxxxxxx>
---
 drivers/gpu/drm/imagination/pvr_mmu.c | 27 ++++++++++++++-------------
 drivers/gpu/drm/imagination/pvr_mmu.h |  3 ++-
 drivers/gpu/drm/imagination/pvr_vm.c  |  5 +++--
 3 files changed, 19 insertions(+), 16 deletions(-)

diff --git a/drivers/gpu/drm/imagination/pvr_mmu.c b/drivers/gpu/drm/imagination/pvr_mmu.c
index 3e494bfa936..dd5f6d32864 100644
--- a/drivers/gpu/drm/imagination/pvr_mmu.c
+++ b/drivers/gpu/drm/imagination/pvr_mmu.c
@@ -2335,7 +2335,8 @@ void pvr_mmu_op_context_destroy(struct pvr_mmu_op_context *op_ctx)
  * pvr_mmu_op_context_create() - Create an MMU op context.
  * @ctx: MMU context associated with owning VM context.
  * @sgt: Scatter gather table containing pages pinned for use by this context.
- * @sgt_offset: Start offset of the requested device-virtual memory mapping.
+ * @sgt_offset: Offset into @sgt of the start of the requested mapping.
+ * @device_addr: Device-virtual address at the start of the requested mapping.
  * @size: Size in bytes of the requested device-virtual memory mapping. For an
  * unmapping, this should be zero so that no page tables are allocated.
  *
@@ -2346,7 +2347,7 @@ void pvr_mmu_op_context_destroy(struct pvr_mmu_op_context *op_ctx)
  */
 struct pvr_mmu_op_context *
 pvr_mmu_op_context_create(struct pvr_mmu_context *ctx, struct sg_table *sgt,
-			  u64 sgt_offset, u64 size)
+			  u64 sgt_offset, u64 device_addr, u64 size)
 {
 	int err;
 
@@ -2362,18 +2363,18 @@ pvr_mmu_op_context_create(struct pvr_mmu_context *ctx, struct sg_table *sgt,
 
 	if (size) {
 		/*
-		 * The number of page table objects we need to prealloc is
-		 * indicated by the mapping size, start offset and the sizes
-		 * of the areas mapped per PT or PD. The range calculation is
-		 * identical to that for the index into a table for a device
-		 * address, so we reuse those functions here.
+		 * The page tables needed are set by the device-virtual range
+		 * being mapped: one level 1 table per 1GiB region and one
+		 * level 0 table per 2MiB region the range touches. Tables that
+		 * already exist are not consumed, so this is an upper bound.
 		 */
-		const u32 l1_start_idx = pvr_page_table_l2_idx(sgt_offset);
-		const u32 l1_end_idx = pvr_page_table_l2_idx(sgt_offset + size);
-		const u32 l1_count = l1_end_idx - l1_start_idx + 1;
-		const u32 l0_start_idx = pvr_page_table_l1_idx(sgt_offset);
-		const u32 l0_end_idx = pvr_page_table_l1_idx(sgt_offset + size);
-		const u32 l0_count = l0_end_idx - l0_start_idx + 1;
+		const u64 last_addr = device_addr + size - 1;
+		const u64 l1_count =
+			(last_addr >> ROGUE_MMUCTRL_VADDR_PC_INDEX_SHIFT) -
+			(device_addr >> ROGUE_MMUCTRL_VADDR_PC_INDEX_SHIFT) + 1;
+		const u64 l0_count =
+			(last_addr >> ROGUE_MMUCTRL_VADDR_PD_INDEX_SHIFT) -
+			(device_addr >> ROGUE_MMUCTRL_VADDR_PD_INDEX_SHIFT) + 1;
 
 		/*
 		 * Alloc and push page table entries until we have enough of
diff --git a/drivers/gpu/drm/imagination/pvr_mmu.h b/drivers/gpu/drm/imagination/pvr_mmu.h
index a8ecd460168..7088f80805e 100644
--- a/drivers/gpu/drm/imagination/pvr_mmu.h
+++ b/drivers/gpu/drm/imagination/pvr_mmu.h
@@ -99,7 +99,8 @@ dma_addr_t pvr_mmu_get_root_table_dma_addr(struct pvr_mmu_context *ctx);
 void pvr_mmu_op_context_destroy(struct pvr_mmu_op_context *op_ctx);
 struct pvr_mmu_op_context *
 pvr_mmu_op_context_create(struct pvr_mmu_context *ctx,
-			  struct sg_table *sgt, u64 sgt_offset, u64 size);
+			  struct sg_table *sgt, u64 sgt_offset,
+			  u64 device_addr, u64 size);
 
 int pvr_mmu_map(struct pvr_mmu_op_context *op_ctx, u64 size, u64 flags,
 		u64 device_addr);
diff --git a/drivers/gpu/drm/imagination/pvr_vm.c b/drivers/gpu/drm/imagination/pvr_vm.c
index c5ae0b79fe6..7bb58ca14e4 100644
--- a/drivers/gpu/drm/imagination/pvr_vm.c
+++ b/drivers/gpu/drm/imagination/pvr_vm.c
@@ -276,7 +276,8 @@ pvr_vm_bind_op_map_init(struct pvr_vm_bind_op *bind_op,
 		goto err_bind_op_fini;
 
 	bind_op->mmu_op_ctx =
-		pvr_mmu_op_context_create(vm_ctx->mmu_ctx, sgt, offset, size);
+		pvr_mmu_op_context_create(vm_ctx->mmu_ctx, sgt, offset,
+					  device_addr, size);
 	err = PTR_ERR_OR_ZERO(bind_op->mmu_op_ctx);
 	if (err) {
 		bind_op->mmu_op_ctx = NULL;
@@ -318,7 +319,7 @@ pvr_vm_bind_op_unmap_init(struct pvr_vm_bind_op *bind_op,
 	}
 
 	bind_op->mmu_op_ctx =
-		pvr_mmu_op_context_create(vm_ctx->mmu_ctx, NULL, 0, 0);
+		pvr_mmu_op_context_create(vm_ctx->mmu_ctx, NULL, 0, 0, 0);
 	err = PTR_ERR_OR_ZERO(bind_op->mmu_op_ctx);
 	if (err) {
 		bind_op->mmu_op_ctx = NULL;

-- 
2.43.0