libpayload: usb mass storage detect empty media

There is currently a hard-coded 30 sec delay in the mass storage
driver while waiting for each device to become ready. However, mass
storage card readers that are empty return an error code on the
TEST UNIT READY command. A REQUEST SENSE command then needs to be
issued and interrogate the data to determine if no media is present.
If no media determination is found to be true the USB device is no
longer considered a candidate to be a disk.

This code does lead to the fact that the media card reader needs to be
populated at enumeration time. I suspect this is not an issue as it
appears the storage stack in libpayload can't handle removable media
coming online later.

Booted recovery and dev modes. Noted that removable mass storage
devices with no media were ignored without any boot delay.

Change-Id: Ida7a45614d97c6e6fbfc9bb099765aad4df550fd
Signed-off-by: Aaron Durbin <adurbin@chromium.org>
Reviewed-on: https://gerrit.chromium.org/gerrit/57828
Reviewed-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: http://review.coreboot.org/4225
Tested-by: build bot (Jenkins)
Reviewed-by: Ronald G. Minnich <rminnich@gmail.com>

1 files changed, 35 insertions, 0 deletions

diff --git a/payloads/libpayload/drivers/usb/usbmsc.c b/payloads/libpayload/drivers/usb/usbmsc.c
index ad7e82f3b0..ffb1c93916 100644
--- a/payloads/libpayload/drivers/usb/usbmsc.c
+++ b/payloads/libpayload/drivers/usb/usbmsc.c
@@ -123,6 +123,8 @@ enum {
 
 static int
 request_sense (usbdev_t *dev);
+static int
+request_sense_no_media (usbdev_t *dev);
 
 static int
 reset_transport (usbdev_t *dev)
@@ -256,6 +258,11 @@ execute_command (usbdev_t *dev, cbw_direction dir, const u8 *cb, int cblen,
 		if (cb[0] == 0x03)
 			/* requesting sense failed, that's bad */
 			return MSC_COMMAND_FAIL;
+		else if (cb[0] == 0)
+			/* If command was TEST UNIT READY determine if the
+			 * device is of removable type indicating no media
+			 * found. */
+			return request_sense_no_media (dev);
 		/* error "check condition" or reserved error */
 		ret = request_sense (dev);
 		/* return fail or the status of request_sense if it's worse */
@@ -350,6 +357,34 @@ request_sense (usbdev_t *dev)
 				sizeof (cb), buf, 19, 1);
 }
 
+static int request_sense_no_media(usbdev_t *dev)
+{
+	u8 buf[19];
+	int ret;
+	cmdblock6_t cb;
+	memset (&cb, 0, sizeof (cb));
+	cb.command = 0x3;
+
+	ret = execute_command (dev, cbw_direction_data_in, (u8 *) &cb,
+				sizeof (cb), buf, 19, 1);
+
+	if (ret)
+		return ret;
+
+	/* Check if sense key is set to NOT READY. */
+	if ((buf[2] & 0xf) != 2)
+		return MSC_COMMAND_FAIL;
+
+	/* Check if additional sense code is 0x3a. */
+	if (buf[12] != 0x3a)
+		return MSC_COMMAND_FAIL;
+
+	/* No media is present. Return MSC_COMMAND_DETACHED so as not to use
+	 * this device any longer. */
+	usb_debug("Empty media found.\n");
+	return MSC_COMMAND_DETACHED;
+}
+
 static int
 test_unit_ready (usbdev_t *dev)
 {