sahara: add chipinfo command to read chip identity

QDL only ever drives Sahara in its image-transfer and memory-debug
modes. Sahara also defines a command mode that lets the primary
bootloader be queried for the device's identity before any programmer
is uploaded. Expose that as a new "chipinfo" subcommand.

It enters command mode by requesting SAHARA_MODE_COMMAND in the HELLO
response and echoing the device's advertised protocol version, then
drives EXECUTE transactions to read the chip serial number, the HW ID
(broken out into MSM_ID / OEM_ID / MODEL_ID) and the OEM PK hash.
Version 3 targets no longer answer MSM_HW_ID_READ, so the same fields
are recovered through READ_CHIP_ID_V3 on those devices.

Command mode is left by switching back to image-transfer mode, which
returns the device to its power-on HELLO state and keeps it usable for
a subsequent query or flash. A Sahara reset is deliberately avoided
here: on some targets it leaves the device enumerated on PID 0x9008 but
no longer answering Sahara until it is power-cycled back into EDL.

This is handy for identifying an attached target and, in particular,
for troubleshooting secure-boot provisioning: the fused OEM PK hash and
OEM ID can be read straight from the PBL without loading a programmer.

Signed-off-by: Igor Opaniuk <igor.opaniuk@oss.qualcomm.com>

Author: igoropaniuk

include/qdl.h

@@ -172,6 +172,7 @@ int firehose_read_buf(struct qdl_device *qdl, struct firehose_op *read_op, void
 int sahara_run(struct qdl_device *qdl, const struct sahara_image *images,
 	       const char *ramdump_path,
 	       const char *ramdump_filter);
+int sahara_chipinfo(struct qdl_device *qdl);
 int load_sahara_image(struct qdl_zip *zip, const char *filename, struct sahara_image *image);
 void sahara_images_free(struct sahara_image *images, size_t count);
 void print_hex_dump(const char *prefix, const void *buf, size_t len);

src/qdl.c

@@ -472,6 +472,7 @@ static void print_usage(FILE *out)
 	fprintf(out, "       %s [options] <prog.mbn> (erase <address>)...\n", __progname);
 	fprintf(out, "       %s [options] <prog.mbn> (sha256 <address>)...\n", __progname);
 	fprintf(out, "       %s list\n", __progname);
+	fprintf(out, "       %s chipinfo\n", __progname);
 	fprintf(out, "       %s ramdump [--debug] [-o <ramdump-path>] [<segment-filter>,...]\n", __progname);
 	fprintf(out, "       %s ks -p <sahara-dev-node> -s <id:file-path>...\n", __progname);
 	fprintf(out, "       %s flash (<flashmap>[::specifier] | <contents>[::<specifier>])\n", __progname);
@@ -640,6 +641,86 @@ static int qdl_ramdump(int argc, char **argv)
 	return ret;
 }
 
+/*
+ * Chip identity ("chipinfo") subcommand.
+ *
+ * Enters Sahara command mode to read and print the device's serial number,
+ * hardware ID (MSM/OEM/model) and OEM PK hash, then resets the device.
+ */
+static int qdl_chipinfo(int argc, char **argv)
+{
+	struct qdl_device *qdl;
+	char *serial = NULL;
+	enum QDL_DEVICE_TYPE qdl_dev_type = QDL_DEVICE_AUTO;
+	int ret = 0;
+	int opt;
+
+	static struct option options[] = {
+		{"debug", no_argument, 0, 'd'},
+		{"version", no_argument, 0, 'v'},
+		{"serial", required_argument, 0, 'S'},
+		{"backend", required_argument, 0, OPT_BACKEND},
+		{"help", no_argument, 0, 'h'},
+		{0, 0, 0, 0}
+	};
+
+	while ((opt = getopt_long(argc, argv, "dvS:h", options, NULL)) != -1) {
+		switch (opt) {
+		case 'd':
+			qdl_debug = true;
+			break;
+		case 'v':
+			print_version();
+			return 0;
+		case 'S':
+			serial = optarg;
+			break;
+		case OPT_BACKEND:
+			if (decode_backend(optarg, &qdl_dev_type) < 0)
+				errx(1, "unknown backend \"%s\" (expected auto|usb|qud)", optarg);
+			break;
+		case 'h':
+			print_usage(stdout);
+			return 0;
+		default:
+			print_usage(stderr);
+			return 1;
+		}
+	}
+
+	if (optind != argc) {
+		print_usage(stderr);
+		return 1;
+	}
+
+	ux_init();
+
+	qdl = qdl_init(qdl_dev_type);
+	if (!qdl) {
+		ux_err("backend not available\n");
+		return 1;
+	}
+
+	if (qdl_debug)
+		print_version();
+
+	ret = qdl_open(qdl, serial);
+	if (ret) {
+		ret = 1;
+		goto out_cleanup;
+	}
+
+	ret = sahara_chipinfo(qdl);
+	if (ret < 0)
+		ret = 1;
+
+out_cleanup:
+	qdl_close(qdl);
+	qdl_deinit(qdl);
+
+	return ret;
+}
+
 /*
  * Sahara kickstart ("ks") subcommand.
  *
@@ -1287,6 +1368,8 @@ int main(int argc, char **argv)
 			return qdl_list(stdout);
 		if (!strcmp(argv[i], "ramdump"))
 			return qdl_ramdump(argc - i, argv + i);
+		if (!strcmp(argv[i], "chipinfo"))
+			return qdl_chipinfo(argc - i, argv + i);
 		if (!strcmp(argv[i], "ks"))
 			return qdl_ks(argc - i, argv + i);
 		if (!strcmp(argv[i], "create-zip"))