Re: [SeaBIOS] usb-msc.c: TEST_UNIT_READY needs USB_DIR_OUT?

[Kevin O'Connor]

On Wed, Mar 14, 2012 at 01:02:39PM -0600, Steve Goodrich wrote:
> I've been working with coreboot and SeaBIOS lately to try to get a platform
> working, including having boot capability using an SD-to-USB adapter.  I got
> stuck on this last part: the USB/SD adapter would start enumeration, but
> would fail out during TEST_UNIT_READY because the device came back with a
> STALL (this via a LeCroy/CACT USB analyzer).  I compared the transactions to
> those done during USB enumeration/configuration in Linux, and I noticed that
> the Direction bit in bmCBWFlags is *cleared* for the TEST_UNIT_READY command
> in Linux, but *set* in coreboot.

If Linux always clears the direction bit for zero length transfers,
then I think it should be safe to do that in SeaBIOS also.  How about
the patch below?

-Kevin
> From 1fd9a89082b807a4bb4ab6ce1285df474cb75746 Mon Sep 17 00:00:00 2001

From: Kevin O'Connor 
Date: Wed, 14 Mar 2012 21:27:45 -0400
Subject: [PATCH] Use OUT mode for all zero byte "scsi" transfers.

Some devices can get confused if asked to "read" data during a zero
byte transfer, so consider these transfers as "writes".  (Reported by
Steve Goodrich.)

Also, extract out the code to determine the transfer direction into
cdb_is_read().

Signed-off-by: Kevin O'Connor 
---
 src/blockcmd.c    |    7 +++++++
 src/blockcmd.h    |    1 +
 src/usb-msc.c     |    4 ++--
 src/virtio-scsi.c |    7 ++++---
 4 files changed, 14 insertions(+), 5 deletions(-)

diff --git a/src/blockcmd.c b/src/blockcmd.c
index 8d881a5..2dda04d 100644
--- a/src/blockcmd.c
+++ b/src/blockcmd.c
@@ -35,6 +35,13 @@ cdb_cmd_data(struct disk_op_s *op, void *cdbcmd, u16 blocksize)
     }
 }

+// Determine if the command is a request to pull data from the device
+int
+cdb_is_read(u8 *cdbcmd, u16 blocksize)
+{
+    return blocksize && cdbcmd[0] != CDB_CMD_WRITE_10;
+}
+
 int
 scsi_is_ready(struct disk_op_s *op)
 {
diff --git a/src/blockcmd.h b/src/blockcmd.h
index ccfeeaf..8459d3e 100644
--- a/src/blockcmd.h
+++ b/src/blockcmd.h
@@ -100,6 +100,7 @@ struct cdbres_mode_sense_geom {
 } PACKED;

// blockcmd.c
+int cdb_is_read(u8 *cdbcmd, u16 blocksize);
 int cdb_get_inquiry(struct disk_op_s *op, struct cdbres_inquiry *data);
 int cdb_get_sense(struct disk_op_s *op, struct cdbres_request_sense *data);
 int cdb_test_unit_ready(struct disk_op_s *op);
diff --git a/src/usb-msc.c b/src/usb-msc.c
index dadb9ca..c53a1f5 100644
--- a/src/usb-msc.c
+++ b/src/usb-msc.c
@@ -77,13 +77,13 @@ usb_cmd_data(struct disk_op_s *op, void *cdbcmd, u16 blocksize)
     cbw.dCBWSignature = CBW_SIGNATURE;
     cbw.dCBWTag = 999; // XXX
     cbw.dCBWDataTransferLength = bytes;
-    cbw.bmCBWFlags = (cbw.CBWCB[0] == CDB_CMD_WRITE_10) ? USB_DIR_OUT : USB_DIR_IN;
+    cbw.bmCBWFlags = cdb_is_read(cdbcmd, blocksize) ? USB_DIR_IN : USB_DIR_OUT;
     cbw.bCBWLUN = 0; // XXX
     cbw.bCBWCBLength = USB_CDB_SIZE;

// Transfer cbw to device.
     int ret = usb_msc_send(udrive_g, USB_DIR_OUT
-                            , MAKE_FLATPTR(GET_SEG(SS), &cbw), sizeof(cbw));
+                           , MAKE_FLATPTR(GET_SEG(SS), &cbw), sizeof(cbw));
     if (ret)
         goto fail;

diff --git a/src/virtio-scsi.c b/src/virtio-scsi.c
index 3c59438..50339d7 100644
--- a/src/virtio-scsi.c
+++ b/src/virtio-scsi.c
@@ -31,7 +31,7 @@ struct virtio_lun_s {

static int
 virtio_scsi_cmd(u16 ioaddr, struct vring_virtqueue *vq, struct disk_op_s *op,
-                void *cdbcmd, u16 target, u16 lun, u32 len)
+                void *cdbcmd, u16 target, u16 lun, u16 blocksize)
 {
     struct virtio_scsi_req_cmd req;
     struct virtio_scsi_resp_cmd resp;
@@ -44,7 +44,8 @@ virtio_scsi_cmd(u16 ioaddr, struct vring_virtqueue *vq, struct disk_op_s *op,
     req.lun[3] = (lun & 0xff);
     memcpy(req.cdb, cdbcmd, 16);

-    int datain = (req.cdb[0] != CDB_CMD_WRITE_10);
+    u32 len = op->count * blocksize;
+    int datain = cdb_is_read(cdbcmd, blocksize);
     int data_idx = (datain ? 2 : 1);
     int out_num = (datain ? 1 : 2);
     int in_num = (len ? 3 : 2) - out_num;
@@ -89,7 +90,7 @@ virtio_scsi_cmd_data(struct disk_op_s *op, void *cdbcmd, u16 blocksize)
     return virtio_scsi_cmd(GET_GLOBAL(vlun->ioaddr),
                            GET_GLOBAL(vlun->vq), op, cdbcmd,
                            GET_GLOBAL(vlun->target), GET_GLOBAL(vlun->lun),
-                           blocksize * op->count);
+                           blocksize);
 }

static int