Patch set updated for coreboot: b4e71fb libpayload: usbmsc: Implement limited LUN support

[Marc Jones]

Marc Jones ([e-mail]) just uploaded a new patch set to gerrit, which you can find at http://review.coreboot.org/7904

-gerrit

commit b4e71fba7e35dd9395bc94e0d22c43049ae449e5
Author: Julius Werner 
Date:   Fri May 2 16:35:50 2014 -0700

libpayload: usbmsc: Implement limited LUN support

I always thought the support for multiple logical SCSI units in the USB
    mass storage class was a dead feature. Turns out that it's actually used
    by SD card readers that provide multiple slots (e.g. one regular sized
    and one micro-SD). Implementing perfect support for that would require a
    major redesign of the whole MSC stack, since the one device -> one disk
    assumption is deeply embedded in our data structures.

Instead, this patch implements a poor man's LUN support that will just
    cycle through all available LUNs (in multiple calls to usb_msc_poll())
    until it finds a connected device. This should be reasonable enough to
    allow these card readers to be usable while only requiring superficial
    changes.

Also removes the unused 'protocol' attribute of usb_msc_inst_t.

BRANCH=rambi?,nyan
    BUG=chrome-os-partner:28437
    TEST=Alternatively plug an SD or micro-SD card (or both) into my card
    reader, confirm that one of them is correctly detected at all times.

Original-Change-Id: I3df4ca88afe2dcf7928b823aa2a73c2b0f599cf2
    Original-Signed-off-by: Julius Werner 
    Original-Reviewed-on: https://chromium-review.googlesource.com/198101
    Original-Reviewed-by: Aaron Durbin 
    (cherry picked from commit 960534a20e4334772c29355bb0d310b3f41b31ee)
    Signed-off-by: Marc Jones

Change-Id: I39909fc96e32c9a5d76651d91c2b5c16c89ace9e
---
 payloads/libpayload/drivers/usb/usbmsc.c | 41 +++++++++++++++++++-------------
 payloads/libpayload/include/usb/usbmsc.h |  7 +++---
 2 files changed, 28 insertions(+), 20 deletions(-)

diff --git a/payloads/libpayload/drivers/usb/usbmsc.c b/payloads/libpayload/drivers/usb/usbmsc.c
index 3b5206e..62428b6 100644
--- a/payloads/libpayload/drivers/usb/usbmsc.c
+++ b/payloads/libpayload/drivers/usb/usbmsc.c
@@ -170,10 +170,10 @@ reset_transport (usbdev_t *dev)
 }

/* device may stall this command, so beware! */
-static int
-get_max_luns (usbdev_t *dev)
+static void
+initialize_luns (usbdev_t *dev)
 {
-	unsigned char luns = 75;
+	usbmsc_inst_t *msc = MSC_INST (dev);
    dev_req_t dr;
    dr.bmRequestType = 0;
    dr.data_dir = device_to_host;
@@ -185,23 +185,24 @@ get_max_luns (usbdev_t *dev)
    dr.wValue = 0;
    dr.wIndex = 0;
    dr.wLength = 1;
-	if (dev->controller->control (dev, IN, sizeof (dr), &dr, 1, &luns) < 0)
-		luns = 0;	// assume only 1 lun if req fails
-	return luns;
+	if (dev->controller->control (dev, IN, sizeof (dr), &dr,
+			sizeof (msc->num_luns), &msc->num_luns) < 0)
+		msc->num_luns = 0;	/* assume only 1 lun if req fails */
+	msc->num_luns++;	/* Get Max LUN returns number of last LUN */
+	msc->lun = 0;
 }

unsigned int tag;
-unsigned char lun = 0;

static void
 wrap_cbw (cbw_t *cbw, int datalen, cbw_direction dir, const u8 *cmd,
-	  int cmdlen)
+	  int cmdlen, u8 lun)
 {
    memset (cbw, 0, sizeof (cbw_t));

cbw->dCBWSignature = cbw_signature;
    cbw->dCBWTag = ++tag;
-	cbw->bCBWLUN = lun;	// static value per device
+	cbw->bCBWLUN = lun;

cbw->dCBWDataTransferLength = datalen;
    cbw->bmCBWFlags = dir;
@@ -236,7 +237,7 @@ execute_command (usbdev_t *dev, cbw_direction dir, const u8 *cb, int cblen,
    if ((cb[0] == 0x1b) && (cb[4] == 1)) {	//start command, always succeed
    	always_succeed = 1;
    }
-	wrap_cbw (&cbw, buflen, dir, cb, cblen);
+	wrap_cbw (&cbw, buflen, dir, cb, cblen, MSC_INST (dev)->lun);
    if (dev->controller->
        bulk (MSC_INST (dev)->bulk_out, sizeof (cbw), (u8 *) &cbw, 0) < 0) {
    	return reset_transport (dev);
@@ -623,7 +624,6 @@ usb_msc_init (usbdev_t *dev)
    if (!dev->data)
    	fatal("Not enough memory for USB MSC device.\n");

-	MSC_INST (dev)->protocol = interface->bInterfaceSubClass;
    MSC_INST (dev)->bulk_in = 0;
    MSC_INST (dev)->bulk_out = 0;
    MSC_INST (dev)->usbdisk_created = 0;
@@ -655,7 +655,8 @@ usb_msc_init (usbdev_t *dev)
    	MSC_INST (dev)->bulk_in->endpoint,
    	MSC_INST (dev)->bulk_out->endpoint);

-	usb_debug ("  has %d luns\n", get_max_luns (dev) + 1);
+	initialize_luns (dev);
+	usb_debug ("  has %d luns\n", MSC_INST (dev)->num_luns);

/* Test if unit is ready (nothing to do if it isn't). */
    if (usb_msc_test_unit_ready (dev) != USB_MSC_READY)
@@ -668,16 +669,22 @@ usb_msc_init (usbdev_t *dev)
 static void
 usb_msc_poll (usbdev_t *dev)
 {
-	int prev_ready = MSC_INST (dev)->ready;
+	usbmsc_inst_t *msc = MSC_INST (dev);
+	int prev_ready = msc->ready;

if (usb_msc_test_unit_ready (dev) == USB_MSC_DETACHED)
    	return;

-	if (!prev_ready && MSC_INST (dev)->ready) {
-		usb_debug ("usb msc: not ready -> ready\n");
+	if (!prev_ready && msc->ready) {
+		usb_debug ("usb msc: not ready -> ready (lun %d)\n", msc->lun);
    	usb_msc_create_disk (dev);
-	} else if (prev_ready && !MSC_INST (dev)->ready) {
-		usb_debug ("usb msc: ready -> not ready\n");
+	} else if (prev_ready && !msc->ready) {
+		usb_debug ("usb msc: ready -> not ready (lun %d)\n", msc->lun);
    	usb_msc_remove_disk (dev);
+	} else if (!prev_ready && !msc->ready) {
+		u8 new_lun = (msc->lun + 1) % msc->num_luns;
+		usb_debug("usb msc: not ready (lun %d) -> lun %d\n", msc->lun,
+			  new_lun);
+		msc->lun = new_lun;
    }
 }
diff --git a/payloads/libpayload/include/usb/usbmsc.h b/payloads/libpayload/include/usb/usbmsc.h
index 8930156..f4562a5 100644
--- a/payloads/libpayload/include/usb/usbmsc.h
+++ b/payloads/libpayload/include/usb/usbmsc.h
@@ -32,11 +32,12 @@
 typedef struct {
    unsigned int blocksize;
    unsigned int numblocks;
-	unsigned int protocol;
    endpoint_t *bulk_in;
    endpoint_t *bulk_out;
-	int usbdisk_created;
-	int ready;
+	u8 usbdisk_created;
+	s8 ready;
+	u8 lun;
+	u8 num_luns;
    void *data; /* For use by consumers of libpayload. */
 } usbmsc_inst_t;