comm-i2c.c upgrades to protocol v2.

Old i2c code uses protocol v1, which cannot handle veriable-length
response (unknown lenght to calculate checksum).

So, upgrade to procotol v2 anyway since command v1 needs protocol v2.

BUG=chrome-os-partner:11608,
Signed-off-by: Louis Yung-Chieh Lo <yjlou@chromium.org>
BRANCH=None
TEST=on snow, and both command v0/v1 are working on protocol v2.
ectool version
ectool hello
ectool echash
ectool flashinfo
ectool flashprotect
ectool flashwp

Change-Id: Id8532fe51359dce18839d37de8a8c8669754041c
Reviewed-on: https://gerrit.chromium.org/gerrit/31838
Commit-Ready: Yung-Chieh Lo <yjlou@chromium.org>
Reviewed-by: Yung-Chieh Lo <yjlou@chromium.org>
Tested-by: Yung-Chieh Lo <yjlou@chromium.org>

2 files changed, 78 insertions, 51 deletions

diff --git a/util/comm-i2c.c b/util/comm-i2c.c
index 5ff71700fd..d1471495c8 100644
--- a/util/comm-i2c.c
+++ b/util/comm-i2c.c
@@ -32,6 +32,12 @@
 #define debug(...)
 #endif
 
+/* v2 protocol bytes
+ *   OUT: (version, command, size, ... request ..., checksum) */
+#define PROTO_V2_IN    4
+/*   IN:  (command, size, ... response ..., checkcum) */
+#define PROTO_V2_OUT   3
+
 static int i2c_fd = -1;
 
 int comm_init(void)
@@ -73,29 +79,37 @@ int comm_init(void)
 }
 
 
-/* Sends a command to the EC.  Returns the command status code, or
- * -1 if other error. */
+/*
+ * Sends a command to the EC (protocol v2).  Returns the command status code, or
+ * -1 if other error.
+ *
+ * Returns >= 0 for success, or negative if error.
+ *
+ */
 int ec_command(int command, int version, const void *indata, int insize,
 	       void *outdata, int outsize)
 {
 	struct i2c_rdwr_ioctl_data data;
 	int ret = -1;
 	int i;
-	uint8_t res_code;
+	int req_len;
 	uint8_t *req_buf = NULL;
+	int resp_len;
 	uint8_t *resp_buf = NULL;
 	const uint8_t *c;
 	uint8_t *d;
 	uint8_t sum;
 	struct i2c_msg i2c_msg[2];
 
-	if (version > 0) {
-		fprintf(stderr, "Command versions >0 unsupported.\n");
+	if (version > 1) {
+		fprintf(stderr, "Command versions >1 unsupported.\n");
 		return -EC_RES_ERROR;
 	}
 
-	if (i2c_fd < 0)
+	if (i2c_fd < 0) {
+		fprintf(stderr, "i2c_fd is negative: %d\n", i2c_fd);
 		return -EC_RES_ERROR;
+	}
 
 	if (ioctl(i2c_fd, I2C_SLAVE, EC_I2C_ADDR) < 0) {
 		fprintf(stderr, "Cannot set I2C slave address\n");
@@ -109,44 +123,41 @@ int ec_command(int command, int version, const void *indata, int insize,
 	data.msgs = i2c_msg;
 	data.nmsgs = 2;
 
-	if (outsize) {
-		/* allocate larger packet
-		 * (one byte for checksum, one for result code)
-		 */
-		resp_buf = calloc(1, outsize + 2);
-		if (!resp_buf)
-			goto done;
-		i2c_msg[1].len = outsize + 2;
-		i2c_msg[1].buf = (char *)resp_buf;
-	} else {
-		i2c_msg[1].len = 1;
-		i2c_msg[1].buf = (char *)&res_code;
-	}
-
-	if (insize) {
-		/* allocate larger packet
-		 * (one byte for checksum, one for command code)
-		 */
-		req_buf = calloc(1, insize + 2);
-		if (!req_buf)
-			goto done;
-		i2c_msg[0].len = insize + 2;
-		i2c_msg[0].buf = (char *)req_buf;
-		req_buf[0] = command;
-
-		debug("i2c req %02x:", command);
-		/* copy message payload and compute checksum */
-		for (i = 0, sum = 0, c = indata; i < insize; i++, c++) {
-			req_buf[i + 1] = *c;
-			sum += *c;
-			debug(" %02x", *c);
-		}
-		debug(", sum=%02x\n", sum);
-		req_buf[insize + 1] = sum;
-	} else {
-		i2c_msg[0].len = 1;
-		i2c_msg[0].buf = (char *)&command; /* nasty cast */
+	/*
+	 * allocate larger packet
+	 * (version, command, size, ..., checksum)
+	 */
+	req_len = insize + PROTO_V2_IN;
+	req_buf = calloc(1, req_len);
+	if (!req_buf)
+		goto done;
+	i2c_msg[0].len = req_len;
+	i2c_msg[0].buf = (char *)req_buf;
+	req_buf[0] = version + EC_CMD_VERSION0;
+	req_buf[1] = command;
+	req_buf[2] = insize;
+
+	debug("i2c req %02x:", command);
+	sum = req_buf[0] + req_buf[1] + req_buf[2];
+	/* copy message payload and compute checksum */
+	for (i = 0, c = indata; i < insize; i++, c++) {
+		req_buf[i + 3] = *c;
+		sum += *c;
+		debug(" %02x", *c);
 	}
+	debug(", sum=%02x\n", sum);
+	req_buf[req_len - 1] = sum;
+
+	/*
+	 * allocate larger packet
+	 * (result, size, ..., checksum)
+	 */
+	resp_len = outsize + PROTO_V2_OUT;
+	resp_buf = calloc(1, resp_len);
+	if (!resp_buf)
+		goto done;
+	i2c_msg[1].len = resp_len;
+	i2c_msg[1].buf = (char *)resp_buf;
 
 	/* send command to EC and read answer */
 	ret = ioctl(i2c_fd, I2C_RDWR, &data);
@@ -158,7 +169,17 @@ int ec_command(int command, int version, const void *indata, int insize,
 	}
 
 	/* check response error code */
-	ret = i2c_msg[1].buf[0];
+	ret = resp_buf[0];
+	/* TODO: handle EC_RES_IN_PROGRESS case. */
+
+	resp_len = resp_buf[1];
+	if (resp_len > outsize) {
+		fprintf(stderr, "response size is too large %d > %d\n",
+				resp_len, outsize);
+		ret = -EC_RES_ERROR;
+		goto done;
+	}
+
 	if (ret) {
 		debug("command 0x%02x returned an error %d\n",
 			 command, i2c_msg[1].buf[0]);
@@ -167,21 +188,22 @@ int ec_command(int command, int version, const void *indata, int insize,
 	} else if (outsize) {
 		debug("i2c resp  :");
 		/* copy response packet payload and compute checksum */
-		for (i = 0, sum = 0, d = outdata; i < outsize; i++, d++) {
-			*d = resp_buf[i + 1];
+		sum = resp_buf[0] + resp_buf[1];
+		for (i = 0, d = outdata; i < resp_len; i++, d++) {
+			*d = resp_buf[i + 2];
 			sum += *d;
 			debug(" %02x", *d);
 		}
 		debug(", sum=%02x\n", sum);
 
-		if (sum != resp_buf[outsize + 1]) {
-			debug("bad packet checksum\n");
+		if (sum != resp_buf[resp_len + 2]) {
+			fprintf(stderr, "bad packet checksum\n");
 			ret = -EC_RES_ERROR;
 			goto done;
 		}
 
 		/* Return output buffer size */
-		ret = outsize;
+		ret = resp_len;
 	}
 done:
 	if (resp_buf)
diff --git a/util/ectool.c b/util/ectool.c
index 0623dc7e7f..1fc7009479 100644
--- a/util/ectool.c
+++ b/util/ectool.c
@@ -296,12 +296,17 @@ int cmd_version(int argc, char *argv[])
 
 	rv = ec_command(EC_CMD_GET_VERSION, 0,
 			NULL, 0, &r, sizeof(r));
-	if (rv < 0)
+	if (rv < 0) {
+		fprintf(stderr, "ERROR: EC_CMD_GET_VERSION failed: %d\n", rv);
 		return rv;
+	}
 	rv = ec_command(EC_CMD_GET_BUILD_INFO, 0,
 			NULL, 0, build_string, sizeof(build_string));
-	if (rv < 0)
+	if (rv < 0) {
+		fprintf(stderr, "ERROR: EC_CMD_GET_BUILD_INFO failed: %d\n",
+				rv);
 		return rv;
+	}
 
 	/* Ensure versions are null-terminated before we print them */
 	r.version_string_ro[sizeof(r.version_string_ro) - 1] = '\0';