usb_updater: refactor section transfer into a function

In preparation to RW and RO cr50 updates, separate the code
transferring an image section (an RW section currently) into a
function.

This will allow to add RO transfer by invoking the same function with
different address and size parameters.

BRANCH=none
BUG=chrome-os-partner:55789
TEST=verified that it is still possible to update to RW_A and RW_B
     both over USB and SPI.

Change-Id: Ia41317e0eefe114bac41e73c7e715b1a5cb6549c
Signed-off-by: Vadim Bendebury <vbendeb@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/368988
Reviewed-by: Aseda Aboagye <aaboagye@chromium.org>

1 files changed, 84 insertions, 61 deletions

diff --git a/extra/usb_updater/usb_updater.c b/extra/usb_updater/usb_updater.c
index 364e8039a3..bbb276652e 100644
--- a/extra/usb_updater/usb_updater.c
+++ b/extra/usb_updater/usb_updater.c
@@ -477,72 +477,40 @@ static int transfer_block(struct usb_endpoint *uep, struct update_pdu *updu,
 	return 0;
 }
 
-static void transfer_and_reboot(struct transfer_endpoint *tep,
-				uint8_t *data, uint32_t data_len)
+/**
+ * Transfer an image section (typically RW or RO).
+ *
+ * tep          - transfer endpoint to use to communicate with the target
+ * data_ptr     - pointer at the section base in the image
+ * section_addr - address of the section in the target memory space
+ * data_len     - section size
+ */
+static void transfer_section(struct transfer_endpoint *tep,
+			     uint8_t *data_ptr,
+			     uint32_t section_addr,
+			     size_t data_len)
 {
-	uint32_t out;
-	uint32_t reply;
-	uint8_t *data_ptr;
-	uint32_t next_offset;
-	struct update_pdu updu;
-	struct startup_resp first_resp;
-	size_t rxed_size;
-	struct usb_endpoint *uep = &tep->uep;
-
-	/* Send start/erase request */
-	printf("erase\n");
-
-	memset(&updu, 0, sizeof(updu));
-	updu.block_size = htobe32(sizeof(updu));
-
-	if (tep->ep_type == usb_xfer) {
-		do_xfer(uep, &updu, sizeof(updu), &first_resp,
-			sizeof(first_resp), 1, &rxed_size);
-	} else {
-		rxed_size = sizeof(first_resp);
-		if (tpm_send_pkt(tep->tpm_fd, 0, 0, NULL, 0,
-				 &first_resp, &rxed_size) < 0) {
-			perror("Failed to start transfer");
-			return;
-		}
-	}
-
-	if (rxed_size == sizeof(uint32_t))
-		protocol_version = 0;
-	else
-		protocol_version = be32toh(first_resp.version);
-
-	printf("Target running protocol version %d\n", protocol_version);
-
-	reply = be32toh(first_resp.value);
-
-	if (reply < 256) {
-		fprintf(stderr, "Target reports error %d\n", reply);
-		shut_down(uep);
-	}
-
-	next_offset = reply - FLASH_BASE;
-	data_ptr = data + next_offset;
-	data_len = CONFIG_RW_SIZE;
-
-	/* Actually, we can skip trailing chunks of 0xff */
+	/*
+	 * Actually, we can skip trailing chunks of 0xff, as the entire
+	 * section space must be erased before the update is attempted.
+	 */
 	while (data_len && (data_ptr[data_len - 1] == 0xff))
 		data_len--;
 
-	printf("sending 0x%x/0x%x bytes to %#x\n", data_len, CONFIG_RW_SIZE,
-	       next_offset);
+	printf("sending 0x%zx bytes to %#x\n", data_len, section_addr);
 	while (data_len) {
 		size_t payload_size;
 		SHA_CTX ctx;
 		uint8_t digest[SHA_DIGEST_LENGTH];
 		int max_retries;
+		struct update_pdu updu;
 
 		/* prepare the header to prepend to the block. */
 		payload_size = MIN(data_len, SIGNED_TRANSFER_SIZE);
 		updu.block_size = htobe32(payload_size +
 					  sizeof(struct update_pdu));
 
-		updu.cmd.block_base = htobe32(next_offset + FLASH_BASE);
+		updu.cmd.block_base = htobe32(section_addr);
 
 		/* Calculate the digest. */
 		SHA1_Init(&ctx);
@@ -556,42 +524,97 @@ static void transfer_and_reboot(struct transfer_endpoint *tep,
 		       sizeof(updu.cmd.block_digest));
 		if (tep->ep_type == usb_xfer) {
 			for (max_retries = 10; max_retries; max_retries--)
-				if (!transfer_block(uep, &updu,
+				if (!transfer_block(&tep->uep, &updu,
 						    data_ptr, payload_size))
 					break;
 
 			if (!max_retries) {
 				fprintf(stderr,
-					"Failed to trasfer block, %d to go\n",
+					"Failed to trasfer block, %zd to go\n",
 					data_len);
 				exit(1);
 			}
 		} else {
-			rxed_size = sizeof(first_resp);
+			struct startup_resp resp;
+			size_t rxed_size;
+
+			rxed_size = sizeof(resp);
 			if (tpm_send_pkt(tep->tpm_fd,
 					 updu.cmd.block_digest,
-					 next_offset + FLASH_BASE,
-			  data_ptr,
-					 payload_size, &first_resp,
+					 section_addr,
+					 data_ptr,
+					 payload_size, &resp,
 					 &rxed_size) < 0) {
 				fprintf(stderr,
-					"Failed to trasfer block, %d to go\n",
+					"Failed to trasfer block, %zd to go\n",
 					data_len);
 				exit(1);
 			}
-			if ((rxed_size != 1) || *((uint8_t *)&first_resp)) {
+			if ((rxed_size != 1) || *((uint8_t *)&resp)) {
 				fprintf(stderr,
 					"got response of size %zd, value %#x\n",
-					rxed_size, first_resp.value);
+					rxed_size, resp.value);
 
 				exit(1);
 			}
 		}
 		data_len -= payload_size;
 		data_ptr += payload_size;
-		next_offset += payload_size;
+		section_addr += payload_size;
 	}
 
+}
+
+static void transfer_and_reboot(struct transfer_endpoint *tep,
+				uint8_t *data, size_t data_len)
+{
+	uint32_t out;
+	uint32_t reply;
+	struct update_pdu updu;
+	struct startup_resp first_resp;
+	size_t rxed_size;
+	struct usb_endpoint *uep = &tep->uep;
+
+	/* Send start/erase request */
+	printf("erase\n");
+
+	memset(&updu, 0, sizeof(updu));
+	updu.block_size = htobe32(sizeof(updu));
+
+	if (tep->ep_type == usb_xfer) {
+		do_xfer(uep, &updu, sizeof(updu), &first_resp,
+			sizeof(first_resp), 1, &rxed_size);
+	} else {
+		rxed_size = sizeof(first_resp);
+		if (tpm_send_pkt(tep->tpm_fd, 0, 0, NULL, 0,
+				 &first_resp, &rxed_size) < 0) {
+			perror("Failed to start transfer");
+			return;
+		}
+	}
+
+	if (rxed_size == sizeof(uint32_t))
+		protocol_version = 0;
+	else
+		protocol_version = be32toh(first_resp.version);
+
+	printf("Target running protocol version %d\n", protocol_version);
+
+	reply = be32toh(first_resp.value);
+
+	if (reply < 256) {
+		fprintf(stderr, "Target reports error %d\n", reply);
+		shut_down(uep);
+	}
+
+	if ((reply - FLASH_BASE + CONFIG_RW_SIZE) > data_len) {
+		fprintf(stderr, "Base addr of %#x too high\n", reply);
+		shut_down(uep);
+	}
+
+	transfer_section(tep, data + reply - FLASH_BASE,
+			 reply, CONFIG_RW_SIZE);
+
 	printf("-------\nupdate complete\n");
 	if (tep->ep_type != usb_xfer)
 		return;