[PATCH v2 19/29] drm/xe: Add GPUSVM devic memory copy vfunc functions

[Matthew Brost]

Add GPUSVM devic memory copy vfunc functions and connect to migration
layer.

v2:
 - Allow NULL device pages in xe_svm_copy
 - Use new drm_gpusvm_devmem_ops

Signed-off-by: Matthew Brost <matthew.brost at intel.com>
---
 drivers/gpu/drm/xe/xe_svm.c | 150 ++++++++++++++++++++++++++++++++++++
 1 file changed, 150 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_svm.c b/drivers/gpu/drm/xe/xe_svm.c
index 22e6341117bd..b33fd42d035b 100644
--- a/drivers/gpu/drm/xe/xe_svm.c
+++ b/drivers/gpu/drm/xe/xe_svm.c
@@ -6,6 +6,7 @@
 #include "drm_gpusvm.h"
 
 #include "xe_gt_tlb_invalidation.h"
+#include "xe_migrate.h"
 #include "xe_pt.h"
 #include "xe_svm.h"
 #include "xe_vm.h"
@@ -269,6 +270,155 @@ static void xe_svm_garbage_collector_work_func(struct work_struct *w)
 	up_write(&vm->lock);
 }
 
+static struct xe_mem_region *page_to_mr(struct page *page)
+{
+	return container_of(page->pgmap, struct xe_mem_region, pagemap);
+}
+
+static struct xe_tile *mr_to_tile(struct xe_mem_region *mr)
+{
+	return container_of(mr, struct xe_tile, mem.vram);
+}
+
+static u64 xe_mem_region_page_to_dpa(struct xe_mem_region *mr,
+				     struct page *page)
+{
+	u64 dpa;
+	struct xe_tile *tile = mr_to_tile(mr);
+	u64 pfn = page_to_pfn(page);
+	u64 offset;
+
+	xe_tile_assert(tile, is_device_private_page(page));
+	xe_tile_assert(tile, (pfn << PAGE_SHIFT) >= mr->hpa_base);
+
+	offset = (pfn << PAGE_SHIFT) - mr->hpa_base;
+	dpa = mr->dpa_base + offset;
+
+	return dpa;
+}
+
+enum xe_svm_copy_dir {
+	XE_SVM_COPY_TO_VRAM,
+	XE_SVM_COPY_TO_SRAM,
+};
+
+static int xe_svm_copy(struct page **pages, dma_addr_t *dma_addr,
+		       unsigned long npages, const enum xe_svm_copy_dir dir)
+{
+	struct xe_mem_region *mr = NULL;
+	struct xe_tile *tile;
+	struct dma_fence *fence = NULL;
+	unsigned long i;
+#define VRAM_ADDR_INVALID	~0x0ull
+	u64 vram_addr = VRAM_ADDR_INVALID;
+	int err = 0, pos = 0;
+	bool sram = dir == XE_SVM_COPY_TO_SRAM;
+
+	for (i = 0; i < npages; ++i) {
+		struct page *spage = pages[i];
+		struct dma_fence *__fence;
+		u64 __vram_addr;
+		bool match = false, chunk, last;
+
+		chunk = (i - pos) == (SZ_2M / PAGE_SIZE);
+		last = (i + 1) == npages;
+
+		if (!dma_addr[i] && vram_addr == VRAM_ADDR_INVALID)
+			continue;
+
+		if (!mr && spage) {
+			mr = page_to_mr(spage);
+			tile = mr_to_tile(mr);
+		}
+
+		if (dma_addr[i] && spage) {
+			__vram_addr = xe_mem_region_page_to_dpa(mr, spage);
+			if (vram_addr == VRAM_ADDR_INVALID) {
+				vram_addr = __vram_addr;
+				pos = i;
+			}
+
+			match = vram_addr + PAGE_SIZE * (i - pos) == __vram_addr;
+		}
+
+		if (!match || chunk || last) {
+			int incr = (match && last) ? 1 : 0;
+
+			if (vram_addr != VRAM_ADDR_INVALID) {
+				if (sram)
+					__fence = xe_migrate_from_vram(tile->migrate,
+								       i - pos + incr,
+								       vram_addr,
+								       dma_addr + pos);
+				else
+					__fence = xe_migrate_to_vram(tile->migrate,
+								     i - pos + incr,
+								     dma_addr + pos,
+								     vram_addr);
+				if (IS_ERR(__fence)) {
+					err = PTR_ERR(__fence);
+					goto err_out;
+				}
+
+				dma_fence_put(fence);
+				fence = __fence;
+			}
+
+			if (dma_addr[i] && spage) {
+				vram_addr = __vram_addr;
+				pos = i;
+			} else {
+				vram_addr = VRAM_ADDR_INVALID;
+			}
+
+			if (!match && last && dma_addr[i] && spage) {
+				if (sram)
+					__fence = xe_migrate_from_vram(tile->migrate, 1,
+								       vram_addr,
+								       dma_addr + pos);
+				else
+					__fence = xe_migrate_to_vram(tile->migrate, 1,
+								     dma_addr + pos,
+								     vram_addr);
+				if (IS_ERR(__fence)) {
+					err = PTR_ERR(__fence);
+					goto err_out;
+				}
+
+				dma_fence_put(fence);
+				fence = __fence;
+			}
+		}
+	}
+
+err_out:
+	if (fence) {
+		dma_fence_wait(fence, false);
+		dma_fence_put(fence);
+	}
+
+	return err;
+#undef VRAM_ADDR_INVALID
+}
+
+static int xe_svm_copy_to_devmem(struct page **pages, dma_addr_t *dma_addr,
+				 unsigned long npages)
+{
+	return xe_svm_copy(pages, dma_addr, npages, XE_SVM_COPY_TO_VRAM);
+}
+
+static int xe_svm_copy_to_ram(struct page **pages, dma_addr_t *dma_addr,
+			      unsigned long npages)
+{
+	return xe_svm_copy(pages, dma_addr, npages, XE_SVM_COPY_TO_SRAM);
+}
+
+__maybe_unused
+static const struct drm_gpusvm_devmem_ops gpusvm_devmem_ops = {
+	.copy_to_devmem = xe_svm_copy_to_devmem,
+	.copy_to_ram = xe_svm_copy_to_ram,
+};
+
 static const struct drm_gpusvm_ops gpusvm_ops = {
 	.range_alloc = xe_svm_range_alloc,
 	.range_free = xe_svm_range_free,
-- 
2.34.1