usb_updater: stop supporting protocol versions below 5

There are no early H1 chips left in circulation, all released chips
(starting with RW 0.0.10) support update protocol version 5.

This patch drops all technical debt associated with supporting earlier
protocol versions.

BRANCH=cr50
BUG=b:35580805
TEST=downgraded an H1 test board to ro 0.0.8 rw 0.0.9. Updated it to
     the latest image (ro 0.0.10 rw 0.0.18).

Original Change-Id: I28c9b0c597122c7aa602a88fb56f9c7bf04b9984
Original Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Original Reviewed-on: https://chromium-review.googlesource.com/457500
Original Reviewed-by: Nicolas Boichat <drinkcat@chromium.org>

Change-Id: I181af7f613414f7c5458d35337f10fabdd3966b7
Reviewed-on: https://chromium-review.googlesource.com/958706
Reviewed-by: Vadim Bendebury <vbendeb@chromium.org>
Tested-by: Vadim Bendebury <vbendeb@chromium.org>
Tested-by: Marco Chen <marcochen@chromium.org>
Commit-Queue: Marco Chen <marcochen@chromium.org>

1 files changed, 47 insertions, 107 deletions

diff --git a/extra/usb_updater/usb_updater.c b/extra/usb_updater/usb_updater.c
index e688b57cf6..f4e98978ea 100644
--- a/extra/usb_updater/usb_updater.c
+++ b/extra/usb_updater/usb_updater.c
@@ -97,6 +97,9 @@
  *
  * The response to the first PDU varies depending on the protocol version.
  *
+ * Note that protocol versions before 5 are described here for completeness,
+ * but are not supported any more by this utility.
+ *
  * Version 1 is used over /dev/tpm0. The response is either 4 or 1 bytes in
  * size. The 4 byte response is the *base address* of the backup RW section,
  * no support for RO updates. The one byte response is an error indication,
@@ -157,8 +160,6 @@
 #define SUBCLASS USB_SUBCLASS_GOOGLE_CR50
 #define PROTOCOL USB_PROTOCOL_GOOGLE_CR50_NON_HC_FW_UPDATE
 
-#define FLASH_BASE 0x40000
-
 enum exit_values {
 	noop = 0,	  /* All up to date, no update needed. */
 	all_updated = 1,  /* Update completed, reboot required. */
@@ -592,7 +593,7 @@ static int transfer_block(struct usb_endpoint *uep, struct update_pdu *updu,
 				 (void *) &reply, sizeof(reply),
 				 &actual, 1000);
 	if (r) {
-		if ((r == -7) && (protocol_version >= 2)) {
+		if (r == -7) {
 			fprintf(stderr, "Timeout!\n");
 			return r;
 		}
@@ -600,11 +601,7 @@ static int transfer_block(struct usb_endpoint *uep, struct update_pdu *updu,
 		shut_down(uep);
 	}
 
-	if (protocol_version > 2)
-		reply = *((uint8_t *)&reply);
-	else
-		reply = be32toh(reply);
-
+	reply = *((uint8_t *)&reply);
 	if (reply) {
 		fprintf(stderr, "Error: status %#x\n", reply);
 		exit(update_error);
@@ -646,11 +643,7 @@ static void transfer_section(struct transfer_descriptor *td,
 		updu.block_size = htobe32(payload_size +
 					  sizeof(struct update_pdu));
 
-		if (protocol_version <= 2)
-			updu.cmd.block_base = htobe32(section_addr +
-						      FLASH_BASE);
-		else
-			updu.cmd.block_base = htobe32(section_addr);
+		updu.cmd.block_base = htobe32(section_addr);
 
 		/* Calculate the digest. */
 		SHA1_Init(&ctx);
@@ -679,10 +672,7 @@ static void transfer_section(struct transfer_descriptor *td,
 			size_t rxed_size = sizeof(error_code);
 			uint32_t block_addr;
 
-			if (protocol_version <= 2)
-				block_addr = section_addr + FLASH_BASE;
-			else
-				block_addr = section_addr;
+			block_addr = section_addr;
 
 			/*
 			 * A single byte response is expected, but let's give
@@ -846,16 +836,6 @@ static void pick_sections(struct transfer_descriptor *td)
 			continue;
 		}
 
-		/*
-		 * RO update not supported in versions below 3, another
-		 * invocation will be required once the RW is updated to
-		 * handle protocol 3 or above.
-		 */
-		if (protocol_version < 3) {
-			sections[i].ustatus = not_possible;
-			continue;
-		}
-
 		/* Skip currently active section. */
 		if (offset != td->ro_offset)
 			continue;
@@ -872,6 +852,7 @@ static void pick_sections(struct transfer_descriptor *td)
 static void setup_connection(struct transfer_descriptor *td)
 {
 	size_t rxed_size;
+	size_t i;
 	uint32_t error_code;
 
 	/*
@@ -904,89 +885,50 @@ static void setup_connection(struct transfer_descriptor *td)
 	}
 
 	/* We got something. Check for errors in response */
+	if (rxed_size < 8) {
+		fprintf(stderr, "Unexpected response size %zd: ", rxed_size);
+		for (i = 0; i < rxed_size; i++)
+			fprintf(stderr, " %02x", ((uint8_t *)&start_resp)[i]);
+		fprintf(stderr, "\n");
+		exit(update_error);
+	}
 
-	if (rxed_size <= 4) {
-		if (td->ep_type != dev_xfer) {
-			size_t i;
+	protocol_version = be32toh(start_resp.rpdu.protocol_version);
+	if (protocol_version < 5) {
+		fprintf(stderr, "Unsupported protocol version %d\n",
+			protocol_version);
+		exit(update_error);
+	}
 
-			fprintf(stderr, "Unexpected response size %zd: ",
-				rxed_size);
+	printf("target running protocol version %d\n", protocol_version);
 
-			for (i = 0; i < rxed_size; i++)
-				fprintf(stderr, " %02x",
-					((uint8_t *)&start_resp)[i]);
-			fprintf(stderr, "\n");
-			exit(update_error);
-		}
+	error_code = be32toh(start_resp.rpdu.return_value);
 
-		/* This is a protocol version one response. */
-		protocol_version = 1;
-		if (rxed_size == 1) {
-			/* Target is reporting an error. */
-			error_code = *((uint8_t *) &start_resp);
-		} else {
-			/* Target reporting RW base_address. */
-			td->rw_offset = be32toh(start_resp.legacy_resp) -
-				FLASH_BASE;
-			error_code = 0;
-		}
-	} else {
-		protocol_version = be32toh(start_resp.rpdu.protocol_version);
-		error_code = be32toh(start_resp.rpdu.return_value);
+	if (error_code) {
+		fprintf(stderr, "Target reporting error %d\n", error_code);
+		if (td->ep_type == usb_xfer)
+			shut_down(&td->uep);
+		exit(update_error);
+	}
 
-		if (protocol_version == 2) {
-			if (error_code > 256) {
-				td->rw_offset = error_code - FLASH_BASE;
-				error_code = 0;
-			}
-		} else {
-			/* All newer protocols. */
-			td->rw_offset = be32toh
-				(start_resp.rpdu.backup_rw_offset);
-
-			if (protocol_version > 3) {
-				size_t i;
-
-				/* Running header versions are available. */
-				for (i = 0; i < ARRAY_SIZE(targ.shv); i++) {
-					targ.shv[i].minor = be32toh
-						(start_resp.rpdu.shv[i].minor);
-					targ.shv[i].major = be32toh
-						(start_resp.rpdu.shv[i].major);
-					targ.shv[i].epoch = be32toh
-						(start_resp.rpdu.shv[i].epoch);
-				}
-			}
-			if (protocol_version > 4) {
-				size_t i;
+	td->rw_offset = be32toh(start_resp.rpdu.backup_rw_offset);
+	td->ro_offset = be32toh(start_resp.rpdu.backup_ro_offset);
 
-				for (i = 0; i < ARRAY_SIZE(targ.keyid); i++)
-					targ.keyid[i] = be32toh
-						(start_resp.rpdu.keyid[i]);
-			}
-		}
+	/* Running header versions. */
+	for (i = 0; i < ARRAY_SIZE(targ.shv); i++) {
+		targ.shv[i].minor = be32toh(start_resp.rpdu.shv[i].minor);
+		targ.shv[i].major = be32toh(start_resp.rpdu.shv[i].major);
+		targ.shv[i].epoch = be32toh(start_resp.rpdu.shv[i].epoch);
 	}
 
-	printf("target running protocol version %d\n", protocol_version);
+	for (i = 0; i < ARRAY_SIZE(targ.keyid); i++)
+		targ.keyid[i] = be32toh(start_resp.rpdu.keyid[i]);
 
-	if (!error_code) {
-		if (protocol_version > 2) {
-			td->ro_offset = be32toh
-				(start_resp.rpdu.backup_ro_offset);
-			printf("offsets: backup RO at %#x, backup RW at %#x\n",
-			       td->ro_offset, td->rw_offset);
-		}
-		if (protocol_version > 4)
-			printf("keyids: RO 0x%08x, RW 0x%08x\n",
-			       targ.keyid[0], targ.keyid[1]);
-		pick_sections(td);
-		return;
-	}
+	printf("keyids: RO 0x%08x, RW 0x%08x\n", targ.keyid[0], targ.keyid[1]);
+	printf("offsets: backup RO at %#x, backup RW at %#x\n",
+	       td->ro_offset, td->rw_offset);
 
-	fprintf(stderr, "Target reporting error %d\n", error_code);
-	if (td->ep_type == usb_xfer)
-		shut_down(&td->uep);
-	exit(update_error);
+	pick_sections(td);
 }
 
 /*
@@ -1048,8 +990,7 @@ static void send_done(struct usb_endpoint *uep)
 
 	/* Send stop request, ignoring reply. */
 	out = htobe32(UPGRADE_DONE);
-	xfer(uep, &out, sizeof(out), &out,
-	     protocol_version < 3 ? sizeof(out) : 1);
+	xfer(uep, &out, sizeof(out), &out, 1);
 }
 
 /*
@@ -1102,13 +1043,12 @@ static int transfer_and_reboot(struct transfer_descriptor *td,
 	printf("-------\nupdate complete\n");
 
 	/*
-	 * In upstart mode, or in case target is running older protocol
-	 * version, or in case the user explicitly wants it, request post
-	 * reset instead of immediate reset. In this case the h1 will reset
-	 * next time the target reboots, and will consider running the
+	 * In upstart mode, or in case the user explicitly wants it, request
+	 * post reset instead of immediate reset. In this case the h1 will
+	 * reset next time the target reboots, and will consider running the
 	 * uploaded code.
 	 */
-	if (td->upstart_mode || (protocol_version <= 5) || td->post_reset)
+	if (td->upstart_mode || td->post_reset)
 		subcommand = EXTENSION_POST_RESET;
 
 	if (td->ep_type == usb_xfer) {