[U-Boot] [PATCH v2 3/3] usb_storage: Fix EHCI "out of buffer pointers" with CD-ROM

Kyle Moffett
2011-12-21T17:08:12Z

When performing large bulk reads from a CD or DVD using the U-Boot
usb_storage driver, it generates requests of up to 20 blocks at a time.

With a standard 512-byte block size, that is 10240 bytes and within the
limit of U-Boot's EHCI driver (maximum 5 pages at 4k per page).

Unfortunately CD-ROM media has a 2048-byte blocksize, resulting in a
maximum transfer size of 40960 bytes, which does not fit.

Since the EHCI specification is impossibly obtuse and far beyond my
comprehension, I chose to dynamically compute the limit based on the
blocksize.

Signed-off-by: Kyle Moffett <Kyle.D.Moffett@boeing.com>

--

v2:
Minor whitespace fixes

---
common/usb_storage.c | 45 +++++++++++++++++++++++++--------------------
1 files changed, 25 insertions(+), 20 deletions(-)

diff --git a/common/usb_storage.c b/common/usb_storage.c
index d9a2585..de84c8d 100644
--- a/common/usb_storage.c
+++ b/common/usb_storage.c
@@ -151,6 +151,7 @@ struct us_data {
unsigned int irqpipe; /* pipe for release_irq */
unsigned char irqmaxp; /* max packed for irq Pipe */
unsigned char irqinterval; /* Intervall for IRQ Pipe */
+ unsigned long max_xfer_blk; /* Max blocks per xfer */
ccb *srb; /* current srb */
trans_reset transport_reset; /* reset routine */
trans_cmnd transport; /* transport routine */
@@ -1041,14 +1042,13 @@ static void usb_bin_fixup(struct usb_device_descriptor descriptor,
}
#endif /* CONFIG_USB_BIN_FIXUP */

-#define USB_MAX_READ_BLK 20
-
unsigned long usb_stor_read(int device, unsigned long blknr,
unsigned long blkcnt, void *buffer)
{
unsigned long start, blks, buf_addr;
unsigned short smallblks;
struct usb_device *dev;
+ struct us_data *ss;
int retry, i;
ccb *srb = &usb_ccb;

@@ -1066,13 +1066,14 @@ unsigned long usb_stor_read(int device, unsigned long blknr,
if (dev->devnum == usb_dev_desc[device].target)
break;
}
+ ss = (struct us_data *)dev->privptr;

usb_disable_asynch(1); /* asynch transfer not allowed */
srb->lun = usb_dev_desc[device].lun;
buf_addr = (unsigned long)buffer;
start = blknr;
blks = blkcnt;
- if (usb_test_unit_ready(srb, (struct us_data *)dev->privptr)) {
+ if (usb_test_unit_ready(srb, ss)) {
printf("Device NOT ready\n Request Sense returned %02X %02X"
" %02X\n", srb->sense_buf[2], srb->sense_buf[12],
srb->sense_buf[13]);
@@ -1086,19 +1087,18 @@ unsigned long usb_stor_read(int device, unsigned long blknr,
/* XXX need some comment here */
retry = 2;
srb->pdata = (unsigned char *)buf_addr;
- if (blks > USB_MAX_READ_BLK)
- smallblks = USB_MAX_READ_BLK;
+ if (blks > ss->max_xfer_blk)
+ smallblks = ss->max_xfer_blk;
else
smallblks = (unsigned short) blks;
retry_it:
- if (smallblks == USB_MAX_READ_BLK)
+ if (smallblks == ss->max_xfer_blk)
usb_show_progress();
srb->datalen = usb_dev_desc[device].blksz * smallblks;
srb->pdata = (unsigned char *)buf_addr;
- if (usb_read_10(srb, (struct us_data *)dev->privptr, start,
- smallblks)) {
+ if (usb_read_10(srb, ss, start, smallblks)) {
USB_STOR_PRINTF("Read ERROR\n");
- usb_request_sense(srb, (struct us_data *)dev->privptr);
+ usb_request_sense(srb, ss);
if (retry--)
goto retry_it;
blkcnt -= blks;
@@ -1113,19 +1113,18 @@ retry_it:
start, smallblks, buf_addr);

usb_disable_asynch(0); /* asynch transfer allowed */
- if (blkcnt >= USB_MAX_READ_BLK)
+ if (blkcnt >= ss->max_xfer_blk)
debug("\n");
return blkcnt;
}

-#define USB_MAX_WRITE_BLK 20
-
unsigned long usb_stor_write(int device, unsigned long blknr,
unsigned long blkcnt, const void *buffer)
{
unsigned long start, blks, buf_addr;
unsigned short smallblks;
struct usb_device *dev;
+ struct us_data *ss;
int retry, i;
ccb *srb = &usb_ccb;

@@ -1143,6 +1142,7 @@ unsigned long usb_stor_write(int device, unsigned long blknr,
if (dev->devnum == usb_dev_desc[device].target)
break;
}
+ ss = (struct us_data *)dev->privptr;

usb_disable_asynch(1); /* asynch transfer not allowed */

@@ -1150,7 +1150,7 @@ unsigned long usb_stor_write(int device, unsigned long blknr,
buf_addr = (unsigned long)buffer;
start = blknr;
blks = blkcnt;
- if (usb_test_unit_ready(srb, (struct us_data *)dev->privptr)) {
+ if (usb_test_unit_ready(srb, ss)) {
printf("Device NOT ready\n Request Sense returned %02X %02X"
" %02X\n", srb->sense_buf[2], srb->sense_buf[12],
srb->sense_buf[13]);
@@ -1166,19 +1166,18 @@ unsigned long usb_stor_write(int device, unsigned long blknr,
*/
retry = 2;
srb->pdata = (unsigned char *)buf_addr;
- if (blks > USB_MAX_WRITE_BLK)
- smallblks = USB_MAX_WRITE_BLK;
+ if (blks > ss->max_xfer_blk)
+ smallblks = ss->max_xfer_blk;
else
smallblks = (unsigned short) blks;
retry_it:
- if (smallblks == USB_MAX_WRITE_BLK)
+ if (smallblks == ss->max_xfer_blk)
usb_show_progress();
srb->datalen = usb_dev_desc[device].blksz * smallblks;
srb->pdata = (unsigned char *)buf_addr;
- if (usb_write_10(srb, (struct us_data *)dev->privptr, start,
- smallblks)) {
+ if (usb_write_10(srb, ss, start, smallblks)) {
USB_STOR_PRINTF("Write ERROR\n");
- usb_request_sense(srb, (struct us_data *)dev->privptr);
+ usb_request_sense(srb, ss);
if (retry--)
goto retry_it;
blkcnt -= blks;
@@ -1193,7 +1192,7 @@ retry_it:
start, smallblks, buf_addr);

usb_disable_asynch(0); /* asynch transfer allowed */
- if (blkcnt >= USB_MAX_WRITE_BLK)
+ if (blkcnt >= ss->max_xfer_blk)
debug("\n");
return blkcnt;

@@ -1419,6 +1418,12 @@ int usb_stor_get_info(struct usb_device *dev, struct us_data *ss,
USB_STOR_PRINTF(" address %d\n", dev_desc->target);
USB_STOR_PRINTF("partype: %d\n", dev_desc->part_type);

+ /*
+ * The U-Boot EHCI driver cannot handle more than 4096 * 5 bytes in a
+ * transfer without running itself out of qt_buffers.
+ */
+ ss->max_xfer_blk = (4096 * 5) / dev_desc->blksz;
+
init_part(dev_desc);

USB_STOR_PRINTF("partype: %d\n", dev_desc->part_type);
--
1.7.7.3