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[ehci] Support arbitrarily large transfers 

Signed-off-by: Michael Brown <mcb30@ipxe.org>
pull/41/head
Michael Brown 2015-09-13 11:48:14 +01:00
parent 6424a38323
commit 8f418ee477
1 changed files with 50 additions and 15 deletions
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63
src/drivers/usb/ehci.c
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@ -1220,6 +1220,30 @@ static int ehci_endpoint_message ( struct usb_endpoint *ep,
return 0;
}
/**
* Calculate number of transfer descriptors
*
* @v len Length of data
* @v zlp Append a zero-length packet
* @ret count Number of transfer descriptors
*/
static unsigned int ehci_endpoint_count ( size_t len, int zlp ) {
unsigned int count;
/* Split into 16kB transfers. A single transfer can handle up
* to 20kB if it happens to be page-aligned, or up to 16kB
* with arbitrary alignment. We simplify the code by assuming
* that we can fit only 16kB into each transfer.
*/
count = ( ( len + EHCI_MTU - 1 ) / EHCI_MTU );
/* Append a zero-length transfer if applicable */
if ( zlp || ( count == 0 ) )
count++;
return count;
}
/**
* Enqueue stream transfer
*
@ -1232,29 +1256,40 @@ static int ehci_endpoint_stream ( struct usb_endpoint *ep,
struct io_buffer *iobuf, int zlp ) {
struct ehci_endpoint *endpoint = usb_endpoint_get_hostdata ( ep );
struct ehci_device *ehci = endpoint->ehci;
unsigned int input = ( ep->address & USB_DIR_IN );
struct ehci_transfer xfers[2];
struct ehci_transfer *xfer = xfers;
void *data = iobuf->data;
size_t len = iob_len ( iobuf );
unsigned int count = ehci_endpoint_count ( len, zlp );
unsigned int input = ( ep->address & USB_DIR_IN );
unsigned int flags = ( input ? EHCI_FL_PID_IN : EHCI_FL_PID_OUT );
struct ehci_transfer xfers[count];
struct ehci_transfer *xfer = xfers;
size_t xfer_len;
unsigned int i;
int rc;
/* Create transfers */
for ( i = 0 ; i < count ; i++ ) {
/* Calculate transfer length */
xfer_len = EHCI_MTU;
if ( xfer_len > len )
xfer_len = len;
/* Create transfer */
xfer->data = iobuf->data;
xfer->len = len;
xfer->flags = ( EHCI_FL_IOC |
( input ? EHCI_FL_PID_IN : EHCI_FL_PID_OUT ) );
xfer++;
if ( zlp ) {
xfer->data = NULL;
xfer->len = 0;
assert ( ! input );
xfer->flags = ( EHCI_FL_IOC | EHCI_FL_PID_OUT );
xfer->data = data;
xfer->len = xfer_len;
xfer->flags = flags;
/* Move to next transfer */
data += xfer_len;
len -= xfer_len;
xfer++;
}
xfer[-1].flags |= EHCI_FL_IOC;
/* Enqueue transfer */
if ( ( rc = ehci_enqueue ( ehci, &endpoint->ring, iobuf, xfers,
( xfer - xfers ) ) ) != 0 )
count ) ) != 0 )
return rc;
return 0;