ASoC: wm_adsp: Split firmware load into smaller chunks

The firmware files can be quite large and allocating the whole firmware
a single DMA safe buffer can be problematic if the system is under a
high memory load. Ease the requirements slightly by writing the firmware
out in page sized chunks.
Signed-off-by: Charles Keepax <ckeepax@opensource.wolfsonmicro.com>
Signed-off-by: Mark Brown <broonie@linaro.org>

sound/soc/codecs/wm_adsp.c

@@ -684,8 +684,16 @@ static int wm_adsp_load(struct wm_adsp *dsp)
 		}
 
 		if (reg) {
-			buf = wm_adsp_buf_alloc(region->data,
-						le32_to_cpu(region->len),
+			size_t to_write = PAGE_SIZE;
+			size_t remain = le32_to_cpu(region->len);
+			const u8 *data = region->data;
+
+			while (remain > 0) {
+				if (remain < PAGE_SIZE)
+					to_write = remain;
+
+				buf = wm_adsp_buf_alloc(data,
+							to_write,
 							&buf_list);
 				if (!buf) {
 					adsp_err(dsp, "Out of memory\n");
@@ -693,16 +701,22 @@ static int wm_adsp_load(struct wm_adsp *dsp)
 					goto out_fw;
 				}
 
-			ret = regmap_raw_write_async(regmap, reg, buf->buf,
-						     le32_to_cpu(region->len));
+				ret = regmap_raw_write_async(regmap, reg,
+							     buf->buf,
+							     to_write);
 				if (ret != 0) {
 					adsp_err(dsp,
 						"%s.%d: Failed to write %d bytes at %d in %s: %d\n",
 						file, regions,
-					le32_to_cpu(region->len), offset,
+						to_write, offset,
 						region_name, ret);
 					goto out_fw;
 				}
+
+				data += to_write;
+				reg += to_write / 2;
+				remain -= to_write;
+			}
 		}
 
 		pos += le32_to_cpu(region->len) + sizeof(*region);