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libpayload: usbmsc: Split transfers into 64KB chunks 

Add a new function to split transfer requests into chunks of
64KB in order to be as compatible as possible with devices that
choke when sent large transfer requests.

Change-Id: Id11990bd149af14af5535de4af47bda21d1ab51e
Signed-off-by: Duncan Laurie <dlaurie@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/169170
Reviewed-by: Julius Werner <jwerner@chromium.org>
(cherry picked from commit 4c413b007aa23da830877127dd556c4c38b43042)
Signed-off-by: Isaac Christensen <isaac.christensen@se-eng.com>
Reviewed-on: http://review.coreboot.org/6636
Tested-by: build bot (Jenkins)
Reviewed-by: Patrick Georgi <patrick@georgi-clan.de>
Reviewed-by: Paul Menzel <paulepanter@users.sourceforge.net>
This commit is contained in:
Duncan Laurie 2013-09-12 13:27:15 -07:00 committed by Isaac Christensen
parent 8f993784ef
commit 3a65d857ea
1 changed files with 47 additions and 1 deletions
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48
payloads/libpayload/drivers/usb/usbmsc.c
View File

@ -125,6 +125,9 @@ usb_msc_destroy (usbdev_t *dev)
const int DEV_RESET = 0xff;
const int GET_MAX_LUN = 0xfe;
/* Many USB3 devices do not work with large transfer requests.
* Limit the request size to 64KB chunks to ensure maximum compatibility. */
const int MAX_CHUNK_BYTES = 1024 * 64;
const unsigned int cbw_signature = 0x43425355;
const unsigned int csw_signature = 0x53425355;
@ -363,7 +366,7 @@ readwrite_blocks_512 (usbdev_t *dev, int start, int n,
* @return 0 on success, 1 on failure
*/
int
readwrite_blocks (usbdev_t *dev, int start, int n, cbw_direction dir, u8 *buf)
readwrite_chunk (usbdev_t *dev, int start, int n, cbw_direction dir, u8 *buf)
{
cmdblock_t cb;
memset (&cb, 0, sizeof (cb));
@ -382,6 +385,49 @@ readwrite_blocks (usbdev_t *dev, int start, int n, cbw_direction dir, u8 *buf)
!= MSC_COMMAND_OK ? 1 : 0;
}
/**
* Reads or writes a number of sequential blocks on a USB storage device
* that is split into MAX_CHUNK_BYTES size requests.
*
* As it uses the READ(10) SCSI-2 command, it's limited to storage devices
* of at most 2TB. It assumes sectors of 512 bytes.
*
* @param dev device to access
* @param start first sector to access
* @param n number of sectors to access
* @param dir direction of access: cbw_direction_data_in == read,
* cbw_direction_data_out == write
* @param buf buffer to read into or write from.
* Must be at least n*sectorsize bytes
* @return 0 on success, 1 on failure
*/
int
readwrite_blocks (usbdev_t *dev, int start, int n, cbw_direction dir, u8 *buf)
{
int chunk_size = MAX_CHUNK_BYTES / MSC_INST(dev)->blocksize;
int chunk;
/* Read as many full chunks as needed. */
for (chunk = 0; chunk < (n / chunk_size); chunk++) {
if (readwrite_chunk (dev, start + (chunk * chunk_size),
chunk_size, dir,
buf + (chunk * MAX_CHUNK_BYTES))
!= MSC_COMMAND_OK)
return 1;
}
/* Read any remaining partial chunk at the end. */
if (n % chunk_size) {
if (readwrite_chunk (dev, start + (chunk * chunk_size),
n % chunk_size, dir,
buf + (chunk * MAX_CHUNK_BYTES))
!= MSC_COMMAND_OK)
return 1;
}
return 0;
}
/* Only request it, we don't interpret it.
On certain errors, that's necessary to get devices out of
a special state called "Contingent Allegiance Condition" */