drm/panthor: Fix firmware initialization on systems with a page size > 4k

The system and GPU MMU page size might differ, which becomes a
problem for FW sections that need to be mapped at explicit addresses
since our PAGE_SIZE alignment might cover a VA range that's
expected to be used for another section.

Make sure we never map more than we need.

Changes in v3:
- Add R-bs

Changes in v2:
- Plan for per-VM page sizes so the MCU VM and user VM can
  have different pages sizes

Fixes: 2718d91816 ("drm/panthor: Add the FW logical block")
Signed-off-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Reviewed-by: Liviu Dudau <liviu.dudau@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241030150231.768949-1-boris.brezillon@collabora.com

drivers/gpu/drm/panthor/panthor_fw.c

@@ -487,6 +487,7 @@ static int panthor_fw_load_section_entry(struct panthor_device *ptdev,
 					 struct panthor_fw_binary_iter *iter,
 					 u32 ehdr)
 {
+	ssize_t vm_pgsz = panthor_vm_page_size(ptdev->fw->vm);
 	struct panthor_fw_binary_section_entry_hdr hdr;
 	struct panthor_fw_section *section;
 	u32 section_size;
@@ -515,8 +516,7 @@ static int panthor_fw_load_section_entry(struct panthor_device *ptdev,
 		return -EINVAL;
 	}
 
-	if ((hdr.va.start & ~PAGE_MASK) != 0 ||
+	if (!IS_ALIGNED(hdr.va.start, vm_pgsz) || !IS_ALIGNED(hdr.va.end, vm_pgsz)) {
-	    (hdr.va.end & ~PAGE_MASK) != 0) {
 		drm_err(&ptdev->base, "Firmware corrupted, virtual addresses not page aligned: 0x%x-0x%x\n",
 			hdr.va.start, hdr.va.end);
 		return -EINVAL;

drivers/gpu/drm/panthor/panthor_gem.c

@@ -44,8 +44,7 @@ void panthor_kernel_bo_destroy(struct panthor_kernel_bo *bo)
 			to_panthor_bo(bo->obj)->exclusive_vm_root_gem != panthor_vm_root_gem(vm)))
 		goto out_free_bo;
 
-	ret = panthor_vm_unmap_range(vm, bo->va_node.start,
+	ret = panthor_vm_unmap_range(vm, bo->va_node.start, bo->va_node.size);
-				     panthor_kernel_bo_size(bo));
 	if (ret)
 		goto out_free_bo;
 
@@ -95,10 +94,16 @@ panthor_kernel_bo_create(struct panthor_device *ptdev, struct panthor_vm *vm,
 	}
 
 	bo = to_panthor_bo(&obj->base);
-	size = obj->base.size;
 	kbo->obj = &obj->base;
 	bo->flags = bo_flags;
 
+	/* The system and GPU MMU page size might differ, which becomes a
+	 * problem for FW sections that need to be mapped at explicit address
+	 * since our PAGE_SIZE alignment might cover a VA range that's
+	 * expected to be used for another section.
+	 * Make sure we never map more than we need.
+	 */
+	size = ALIGN(size, panthor_vm_page_size(vm));
 	ret = panthor_vm_alloc_va(vm, gpu_va, size, &kbo->va_node);
 	if (ret)
 		goto err_put_obj;

drivers/gpu/drm/panthor/panthor_mmu.c

@@ -826,6 +826,14 @@ void panthor_vm_idle(struct panthor_vm *vm)
 	mutex_unlock(&ptdev->mmu->as.slots_lock);
 }
 
+u32 panthor_vm_page_size(struct panthor_vm *vm)
+{
+	const struct io_pgtable *pgt = io_pgtable_ops_to_pgtable(vm->pgtbl_ops);
+	u32 pg_shift = ffs(pgt->cfg.pgsize_bitmap) - 1;
+
+	return 1u << pg_shift;
+}
+
 static void panthor_vm_stop(struct panthor_vm *vm)
 {
 	drm_sched_stop(&vm->sched, NULL);
@@ -1025,12 +1033,13 @@ int
 panthor_vm_alloc_va(struct panthor_vm *vm, u64 va, u64 size,
 		    struct drm_mm_node *va_node)
 {
+	ssize_t vm_pgsz = panthor_vm_page_size(vm);
 	int ret;
 
-	if (!size || (size & ~PAGE_MASK))
+	if (!size || !IS_ALIGNED(size, vm_pgsz))
 		return -EINVAL;
 
-	if (va != PANTHOR_VM_KERNEL_AUTO_VA && (va & ~PAGE_MASK))
+	if (va != PANTHOR_VM_KERNEL_AUTO_VA && !IS_ALIGNED(va, vm_pgsz))
 		return -EINVAL;
 
 	mutex_lock(&vm->mm_lock);
@@ -2366,11 +2375,12 @@ panthor_vm_bind_prepare_op_ctx(struct drm_file *file,
 			       const struct drm_panthor_vm_bind_op *op,
 			       struct panthor_vm_op_ctx *op_ctx)
 {
+	ssize_t vm_pgsz = panthor_vm_page_size(vm);
 	struct drm_gem_object *gem;
 	int ret;
 
 	/* Aligned on page size. */
-	if ((op->va | op->size) & ~PAGE_MASK)
+	if (!IS_ALIGNED(op->va | op->size, vm_pgsz))
 		return -EINVAL;
 
 	switch (op->flags & DRM_PANTHOR_VM_BIND_OP_TYPE_MASK) {

drivers/gpu/drm/panthor/panthor_mmu.h

@@ -30,6 +30,7 @@ panthor_vm_get_bo_for_va(struct panthor_vm *vm, u64 va, u64 *bo_offset);
 
 int panthor_vm_active(struct panthor_vm *vm);
 void panthor_vm_idle(struct panthor_vm *vm);
+u32 panthor_vm_page_size(struct panthor_vm *vm);
 int panthor_vm_as(struct panthor_vm *vm);
 int panthor_vm_flush_all(struct panthor_vm *vm);