HID: intel-ish-hid: Use dma_alloc_coherent for firmware update

Allocating memory with kmalloc and GPF_DMA32 is not allowed, the
allocator will ignore the attribute.

Instead, use dma_alloc_coherent() API as we allocate a small amount of
memory to transfer firmware fragment to the ISH.

On Arcada chromebook, after the patch the warning:
"Unexpected gfp: 0x4 (GFP_DMA32). Fixing up to gfp: 0xcc0 (GFP_KERNEL).  Fix your code!"
is gone. The ISH firmware is loaded properly and we can interact with
the ISH:
> ectool  --name cros_ish version
...
Build info:    arcada_ish_v2.0.3661+3c1a1c1ae0 2022-02-08 05:37:47 @localhost
Tool version:  v2.0.12300-900b03ec7f 2022-02-08 10:01:48 @localhost

Fixes: commit 91b22810 ("HID: intel-ish-hid: ISH firmware loader client driver")
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Acked-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Cc: stable@vger.kernel.org
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

drivers/hid/intel-ish-hid/ishtp-fw-loader.c

@@ -661,21 +661,12 @@ static int ish_fw_xfer_direct_dma(struct ishtp_cl_data *client_data,
 	 */
 	payload_max_size &= ~(L1_CACHE_BYTES - 1);
 
-	dma_buf = kmalloc(payload_max_size, GFP_KERNEL | GFP_DMA32);
+	dma_buf = dma_alloc_coherent(devc, payload_max_size, &dma_buf_phy, GFP_KERNEL);
 	if (!dma_buf) {
 		client_data->flag_retry = true;
 		return -ENOMEM;
 	}
 
-	dma_buf_phy = dma_map_single(devc, dma_buf, payload_max_size,
-				     DMA_TO_DEVICE);
-	if (dma_mapping_error(devc, dma_buf_phy)) {
-		dev_err(cl_data_to_dev(client_data), "DMA map failed\n");
-		client_data->flag_retry = true;
-		rv = -ENOMEM;
-		goto end_err_dma_buf_release;
-	}
-
 	ldr_xfer_dma_frag.fragment.hdr.command = LOADER_CMD_XFER_FRAGMENT;
 	ldr_xfer_dma_frag.fragment.xfer_mode = LOADER_XFER_MODE_DIRECT_DMA;
 	ldr_xfer_dma_frag.ddr_phys_addr = (u64)dma_buf_phy;
@@ -695,14 +686,7 @@ static int ish_fw_xfer_direct_dma(struct ishtp_cl_data *client_data,
 		ldr_xfer_dma_frag.fragment.size = fragment_size;
 		memcpy(dma_buf, &fw->data[fragment_offset], fragment_size);
 
-		dma_sync_single_for_device(devc, dma_buf_phy,
-					   payload_max_size,
-					   DMA_TO_DEVICE);
-
-		/*
-		 * Flush cache here because the dma_sync_single_for_device()
-		 * does not do for x86.
-		 */
+		/* Flush cache to be sure the data is in main memory. */
 		clflush_cache_range(dma_buf, payload_max_size);
 
 		dev_dbg(cl_data_to_dev(client_data),
@@ -725,15 +709,8 @@ static int ish_fw_xfer_direct_dma(struct ishtp_cl_data *client_data,
 		fragment_offset += fragment_size;
 	}
 
-	dma_unmap_single(devc, dma_buf_phy, payload_max_size, DMA_TO_DEVICE);
-	kfree(dma_buf);
-	return 0;
-
 end_err_resp_buf_release:
-	/* Free ISH buffer if not done already, in error case */
-	dma_unmap_single(devc, dma_buf_phy, payload_max_size, DMA_TO_DEVICE);
-end_err_dma_buf_release:
-	kfree(dma_buf);
+	dma_free_coherent(devc, payload_max_size, dma_buf, dma_buf_phy);
 	return rv;
 }