usb_update: Add support for touchpad debugging feature

We support touchpad-specific debugging feature over the USB update
protocol. This will be used to fetch raw data from the sensor,
without requiring to remove the write-protect screw.

BRANCH=none
BUG=b:63993891
TEST=./usb_updater2 -g 00 -d 18d1:502b

Change-Id: I46dfd97aaa17b73a5893fe1e8c62327a302f829b
Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/763574
Reviewed-by: Chun-ta Lin <itspeter@chromium.org>
Reviewed-by: Vincent Palatin <vpalatin@chromium.org>

1 files changed, 25 insertions, 0 deletions

diff --git a/common/usb_update.c b/common/usb_update.c
index c73459126c..a97541dd9c 100644
--- a/common/usb_update.c
+++ b/common/usb_update.c
@@ -326,6 +326,31 @@ static int try_vendor_command(struct consumer const *consumer, size_t count)
 					&tp, response_size);
 			return 1;
 		}
+		case UPDATE_EXTRA_CMD_TOUCHPAD_DEBUG: {
+			uint8_t *data = NULL;
+			unsigned int write_count = 0;
+
+			/*
+			 * Let the touchpad driver decide what it wants to do
+			 * with the payload data, and put the response in data.
+			 */
+			response = touchpad_debug(buffer + header_size,
+					data_count, &data, &write_count);
+
+			/*
+			 * On error, or if there is no data to write back, just
+			 * write back response.
+			 */
+			if (response != EC_RES_SUCCESS || write_count == 0)
+				break;
+
+			/* Check that we can write all the data to the queue. */
+			if (write_count > queue_space(&update_to_usb))
+				return EC_RES_BUSY;
+
+			QUEUE_ADD_UNITS(&update_to_usb, data, write_count);
+			return 1;
+		}
 #endif
 		default:
 			response = EC_RES_INVALID_COMMAND;