g: usb_updater: clean up update protocol handling

In preparation of introducing new update protocol version this patch
cleans up the existing implementation.

The receive and transmit PDU headers are separated into their own
structures and are now shared between the server and client sides.

Some comments have been added to better explain different protocol
versions' details.

BRANCH=none
BUG=chrome-os-partner:55789
TEST=verified that it is still possible to update RW_A and RW_B on a
     Kevin CR50, works using both USB and SPI.

Change-Id: Ied65b2c2a7800bae045f1d2dd64e58dd5e793d27
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/368989
Reviewed-by: Bill Richardson <wfrichar@chromium.org>
Reviewed-by: Mary Ruthven <mruthven@chromium.org>

1 files changed, 5 insertions, 30 deletions

diff --git a/extra/usb_updater/usb_updater.c b/extra/usb_updater/usb_updater.c
index bbb276652e..952f7db3c6 100644
--- a/extra/usb_updater/usb_updater.c
+++ b/extra/usb_updater/usb_updater.c
@@ -403,11 +403,6 @@ static void usb_findit(uint16_t vid, uint16_t pid, struct usb_endpoint *uep)
 	printf("READY\n-------\n");
 }
 
-struct upgrade_command {
-	uint32_t  block_digest;
-	uint32_t  block_base;
-};
-
 struct update_pdu {
 	uint32_t block_size; /* Total block size, include this field's size. */
 	struct upgrade_command cmd;
@@ -415,26 +410,6 @@ struct update_pdu {
 };
 
 #define FLASH_BASE 0x40000
-/*
- * When responding to the very first packet of the upgrade sequence, the
- * original implementation was responding with a four byte value, just as to
- * any other block of the transfer sequence.
- *
- * It became clear that there is a need to be able to enhance the upgrade
- * protocol, while stayng backwards compatible. To achieve that a new startup
- * response option was introduced, 8 bytes in size. The first 4 bytes the same
- * as before, the second 4 bytes - the protocol version number.
- *
- * So, receiving of a four byte value in response to the startup packet is an
- * indication of the 'legacy' protocol, version 0. Receiving of an 8 byte
- * value communicates the protocol version in the second 4 bytes.
- */
-
-struct startup_resp {
-	uint32_t value;
-	uint32_t version;
-};
-
 static int transfer_block(struct usb_endpoint *uep, struct update_pdu *updu,
 			  uint8_t *transfer_data_ptr, size_t payload_size)
 {
@@ -535,7 +510,7 @@ static void transfer_section(struct transfer_endpoint *tep,
 				exit(1);
 			}
 		} else {
-			struct startup_resp resp;
+			struct first_response_pdu resp;
 			size_t rxed_size;
 
 			rxed_size = sizeof(resp);
@@ -553,7 +528,7 @@ static void transfer_section(struct transfer_endpoint *tep,
 			if ((rxed_size != 1) || *((uint8_t *)&resp)) {
 				fprintf(stderr,
 					"got response of size %zd, value %#x\n",
-					rxed_size, resp.value);
+					rxed_size, resp.return_value);
 
 				exit(1);
 			}
@@ -571,7 +546,7 @@ static void transfer_and_reboot(struct transfer_endpoint *tep,
 	uint32_t out;
 	uint32_t reply;
 	struct update_pdu updu;
-	struct startup_resp first_resp;
+	struct first_response_pdu first_resp;
 	size_t rxed_size;
 	struct usb_endpoint *uep = &tep->uep;
 
@@ -596,11 +571,11 @@ static void transfer_and_reboot(struct transfer_endpoint *tep,
 	if (rxed_size == sizeof(uint32_t))
 		protocol_version = 0;
 	else
-		protocol_version = be32toh(first_resp.version);
+		protocol_version = be32toh(first_resp.protocol_version);
 
 	printf("Target running protocol version %d\n", protocol_version);
 
-	reply = be32toh(first_resp.value);
+	reply = be32toh(first_resp.return_value);
 
 	if (reply < 256) {
 		fprintf(stderr, "Target reports error %d\n", reply);