drm/nouveau/nvkm: support loading fws into sg_table

- preparation for GSP-RM, which has massive FW images
- based on a patch by Dave Airlie
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20230918202149.4343-32-skeggsb@gmail.com

drivers/gpu/drm/nouveau/include/nvkm/core/firmware.h

@@ -10,6 +10,7 @@ struct nvkm_firmware {
 		enum nvkm_firmware_type {
 			NVKM_FIRMWARE_IMG_RAM,
 			NVKM_FIRMWARE_IMG_DMA,
+			NVKM_FIRMWARE_IMG_SGT,
 		} type;
 	} *func;
 	const char *name;
@@ -21,7 +22,10 @@ struct nvkm_firmware {
 
 	struct nvkm_firmware_mem {
 		struct nvkm_memory memory;
-		struct scatterlist sgl;
+		union {
+			struct scatterlist sgl; /* DMA */
+			struct sg_table sgt;	/* SGT */
+		};
 	} mem;
 };
 

drivers/gpu/drm/nouveau/nvkm/core/firmware.c

@@ -112,6 +112,22 @@ nvkm_firmware_put(const struct firmware *fw)
 
 #define nvkm_firmware_mem(p) container_of((p), struct nvkm_firmware, mem.memory)
 
+static struct scatterlist *
+nvkm_firmware_mem_sgl(struct nvkm_memory *memory)
+{
+	struct nvkm_firmware *fw = nvkm_firmware_mem(memory);
+
+	switch (fw->func->type) {
+	case NVKM_FIRMWARE_IMG_DMA: return &fw->mem.sgl;
+	case NVKM_FIRMWARE_IMG_SGT: return  fw->mem.sgt.sgl;
+	default:
+		WARN_ON(1);
+		break;
+	}
+
+	return NULL;
+}
+
 static int
 nvkm_firmware_mem_map(struct nvkm_memory *memory, u64 offset, struct nvkm_vmm *vmm,
 		      struct nvkm_vma *vma, void *argv, u32 argc)
@@ -120,10 +136,10 @@ nvkm_firmware_mem_map(struct nvkm_memory *memory, u64 offset, struct nvkm_vmm *v
 	struct nvkm_vmm_map map = {
 		.memory = &fw->mem.memory,
 		.offset = offset,
-		.sgl = &fw->mem.sgl,
+		.sgl = nvkm_firmware_mem_sgl(memory),
 	};
 
-	if (WARN_ON(fw->func->type != NVKM_FIRMWARE_IMG_DMA))
+	if (!map.sgl)
 		return -ENOSYS;
 
 	return nvkm_vmm_map(vmm, vma, argv, argc, &map);
@@ -132,12 +148,15 @@ nvkm_firmware_mem_map(struct nvkm_memory *memory, u64 offset, struct nvkm_vmm *v
 static u64
 nvkm_firmware_mem_size(struct nvkm_memory *memory)
 {
-	return sg_dma_len(&nvkm_firmware_mem(memory)->mem.sgl);
+	struct scatterlist *sgl = nvkm_firmware_mem_sgl(memory);
+
+	return sgl ? sg_dma_len(sgl) : 0;
 }
 
 static u64
 nvkm_firmware_mem_addr(struct nvkm_memory *memory)
 {
+	BUG_ON(nvkm_firmware_mem(memory)->func->type != NVKM_FIRMWARE_IMG_DMA);
 	return nvkm_firmware_mem(memory)->phys;
 }
 
@@ -188,6 +207,12 @@ nvkm_firmware_dtor(struct nvkm_firmware *fw)
 		nvkm_memory_unref(&memory);
 		dma_free_coherent(fw->device->dev, sg_dma_len(&fw->mem.sgl), fw->img, fw->phys);
 		break;
+	case NVKM_FIRMWARE_IMG_SGT:
+		nvkm_memory_unref(&memory);
+		dma_unmap_sgtable(fw->device->dev, &fw->mem.sgt, DMA_TO_DEVICE, 0);
+		sg_free_table(&fw->mem.sgt);
+		vfree(fw->img);
+		break;
 	default:
 		WARN_ON(1);
 		break;
@@ -225,6 +250,49 @@ nvkm_firmware_ctor(const struct nvkm_firmware_func *func, const char *name,
 		sg_dma_len(&fw->mem.sgl) = len;
 	}
 		break;
+	case NVKM_FIRMWARE_IMG_SGT:
+		len = ALIGN(fw->len, PAGE_SIZE);
+
+		fw->img = vmalloc(len);
+		if (fw->img) {
+			int pages = len >> PAGE_SHIFT;
+			int ret = 0;
+
+			memcpy(fw->img, src, fw->len);
+
+			ret = sg_alloc_table(&fw->mem.sgt, pages, GFP_KERNEL);
+			if (ret == 0) {
+				struct scatterlist *sgl;
+				u8 *data = fw->img;
+				int i;
+
+				for_each_sgtable_sg(&fw->mem.sgt, sgl, i) {
+					struct page *page = vmalloc_to_page(data);
+
+					if (!page) {
+						ret = -EFAULT;
+						break;
+					}
+
+					sg_set_page(sgl, page, PAGE_SIZE, 0);
+					data += PAGE_SIZE;
+				}
+
+				if (ret == 0) {
+					ret = dma_map_sgtable(fw->device->dev, &fw->mem.sgt,
+							      DMA_TO_DEVICE, 0);
+				}
+
+				if (ret)
+					sg_free_table(&fw->mem.sgt);
+			}
+
+			if (ret) {
+				vfree(fw->img);
+				fw->img = NULL;
+			}
+		}
+		break;
 	default:
 		WARN_ON(1);
 		return -EINVAL;