g: use devid 0 and 1 to create a serial number

To be able to identify different cr50 devices connected to the same
machine we need a serial number. This change uses dev id 0 and 1 to come
up with one.

BUG=chrome-os-partner:56641
BUG=chrome-os-partner:58342
BRANCH=none
TEST=lsusb -vd 18d1:5014 | grep iSerial shows different numbers for
different devices. Verify when ccd is disabled the serial number is 0.

Change-Id: I85c54af4a21bdfd0542019c02aa8420d9a879fae
Signed-off-by: Mary Ruthven <mruthven@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/395633
Reviewed-by: Bill Richardson <wfrichar@chromium.org>

board/cr50/board.c

@@ -324,6 +324,7 @@ const void * const usb_strings[] = {
 	[USB_STR_EC_NAME] = USB_STRING_DESC("EC"),
 	[USB_STR_UPGRADE_NAME] = USB_STRING_DESC("Firmware upgrade"),
 	[USB_STR_SPI_NAME] = USB_STRING_DESC("AP EC upgrade"),
+	[USB_STR_SERIALNO] = USB_STRING_DESC(DEFAULT_SERIALNO),
 };
 BUILD_ASSERT(ARRAY_SIZE(usb_strings) == USB_STR_COUNT);
 #endif

board/cr50/board.h

@@ -65,6 +65,8 @@
 #define CONFIG_USB_INHIBIT_INIT
 #define CONFIG_USB_SELECT_PHY
 #define CONFIG_USB_SPI
+#define CONFIG_USB_SERIALNO
+#define DEFAULT_SERIALNO "0"
 
 #define CONFIG_STREAM_USART
 #define CONFIG_STREAM_USB
@@ -115,6 +117,7 @@ enum usb_strings {
 	USB_STR_EC_NAME,
 	USB_STR_UPGRADE_NAME,
 	USB_STR_SPI_NAME,
+	USB_STR_SERIALNO,
 
 	USB_STR_COUNT
 };

board/cr50/rdd.c

@@ -34,7 +34,7 @@ static struct uart_config uarts[] = {
 
 static int ccd_is_enabled(void)
 {
-	return !gpio_get_level(GPIO_CCD_MODE_L);
+	return ccd_get_mode() == CCD_MODE_ENABLED;
 }
 
 int is_utmi_wakeup_allowed(void)

chip/g/usb.c

@@ -3,6 +3,7 @@
  * found in the LICENSE file.
  */
 
+#include "case_closed_debug.h"
 #include "clock.h"
 #include "common.h"
 #include "config.h"
@@ -11,6 +12,7 @@
 #include "hooks.h"
 #include "init_chip.h"
 #include "link_defs.h"
+#include "printf.h"
 #include "registers.h"
 #include "system.h"
 #include "task.h"
@@ -26,6 +28,13 @@
 #define CPRINTS(format, args...) cprints(CC_USB, format, ## args)
 #define CPRINTF(format, args...) cprintf(CC_USB, format, ## args)
 
+#define USE_SERIAL_NUMBER (defined(CONFIG_USB_SERIALNO) && \
+			   defined(CONFIG_CASE_CLOSED_DEBUG))
+
+#if !USE_SERIAL_NUMBER
+#define USB_STR_SERIALNO 0
+#endif
+
 /* This is not defined anywhere else. Change it here to debug. */
 #undef DEBUG_ME
 #ifdef DEBUG_ME
@@ -213,7 +222,7 @@ static const struct usb_device_descriptor dev_desc = {
 	.bcdDevice = CONFIG_USB_BCD_DEV,
 	.iManufacturer = USB_STR_VENDOR,
 	.iProduct = USB_STR_PRODUCT,
-	.iSerialNumber = 0,
+	.iSerialNumber = USB_STR_SERIALNO,
 	.bNumConfigurations = 1
 };
 
@@ -598,7 +607,13 @@ static int handle_setup_with_in_stage(enum table_case tc,
 		case USB_DT_STRING:
 			if (idx >= USB_STR_COUNT)
 				return -1;
-			data = usb_strings[idx];
+#if USE_SERIAL_NUMBER
+			if (idx == USB_STR_SERIALNO &&
+			    ccd_get_mode() == CCD_MODE_ENABLED)
+				data = usb_serialno_desc;
+			else
+#endif
+				data = usb_strings[idx];
 			len = *(uint8_t *)data;
 			break;
 		case USB_DT_DEVICE_QUALIFIER:
@@ -1407,3 +1422,64 @@ static int command_usb(int argc, char **argv)
 DECLARE_CONSOLE_COMMAND(usb, command_usb,
 			"[<BOOLEAN> | a | b]",
 			"Get/set the USB connection state and PHY selection");
+
+#if USE_SERIAL_NUMBER
+/* This will be subbed into USB_STR_SERIALNO. */
+struct usb_string_desc *usb_serialno_desc =
+	USB_WR_STRING_DESC(DEFAULT_SERIALNO);
+
+/* Update serial number */
+static int usb_set_serial(const char *serialno)
+{
+	struct usb_string_desc *sd = usb_serialno_desc;
+	int i;
+
+	if (!serialno)
+		return EC_ERROR_INVAL;
+
+	/* Convert into unicode usb string desc. */
+	for (i = 0; i < USB_STRING_LEN; i++) {
+		sd->_data[i] = serialno[i];
+		if (serialno[i] == 0)
+			break;
+	}
+	/* Count wchars (w/o null terminator) plus size & type bytes. */
+	sd->_len = (i * 2) + 2;
+	sd->_type = USB_DT_STRING;
+
+	return EC_SUCCESS;
+}
+
+static void usb_load_serialno(void)
+{
+	char devid_str[20];
+
+	snprintf(devid_str, 20, "%08X-%08X", GREG32(FUSE, DEV_ID0),
+		GREG32(FUSE, DEV_ID1));
+
+	usb_set_serial(devid_str);
+}
+DECLARE_HOOK(HOOK_INIT, usb_load_serialno, HOOK_PRIO_DEFAULT - 1);
+
+static int command_serialno(int argc, char **argv)
+{
+	struct usb_string_desc *sd = usb_serialno_desc;
+	char buf[USB_STRING_LEN];
+	int rv = EC_SUCCESS;
+	int i;
+
+	if (argc != 1) {
+		ccprintf("Setting serial number\n");
+		rv = usb_set_serial(argv[1]);
+	}
+
+	for (i = 0; i < USB_STRING_LEN; i++)
+		buf[i] = sd->_data[i];
+	ccprintf("Serial number: %s\n", buf);
+	return rv;
+}
+
+DECLARE_CONSOLE_COMMAND(serialno, command_serialno,
+	"[value]",
+	"Read and write USB serial number");
+#endif

common/case_closed_debug.c

@@ -60,3 +60,8 @@ void ccd_set_mode(enum ccd_mode new_mode)
 		usb_init();
 #endif
 }
+
+enum ccd_mode ccd_get_mode(void)
+{
+	return current_mode;
+}

include/case_closed_debug.h

@@ -37,4 +37,9 @@ void ccd_set_mode(enum ccd_mode new_mode);
 
 /* Initialize the PHY based on CCD state */
 void ccd_phy_init(int enable_ccd);
+
+/*
+ * Get current CCD mode.
+ */
+enum ccd_mode ccd_get_mode(void);
 #endif /* __CROS_EC_CASE_CLOSED_DEBUG_H */