diff options
| author | Alan Stern <stern@rowland.harvard.edu> | 2009-11-06 12:29:40 -0500 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2009-12-11 11:55:19 -0800 |
| commit | 40f8db8f8f5af2cafeb976ae15e11aca641a931d (patch) | |
| tree | b2da27baeab34919264b60f7679cfef62daa933d /drivers/usb/host/ehci-q.c | |
| parent | 3a2b808e95287c8235e25a833fda3dad3e9853ef (diff) | |
USB: EHCI: add native scatter-gather support
This patch (as1300) adds native scatter-gather support to ehci-hcd.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host/ehci-q.c')
| -rw-r--r-- | drivers/usb/host/ehci-q.c | 32 |
1 files changed, 27 insertions, 5 deletions
diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index 139a2cc3f641..a427d3b00634 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -616,9 +616,11 @@ qh_urb_transaction ( ) { struct ehci_qtd *qtd, *qtd_prev; dma_addr_t buf; - int len, maxpacket; + int len, this_sg_len, maxpacket; int is_input; u32 token; + int i; + struct scatterlist *sg; /* * URBs map to sequences of QTDs: one logical transaction @@ -659,7 +661,20 @@ qh_urb_transaction ( /* * data transfer stage: buffer setup */ - buf = urb->transfer_dma; + i = urb->num_sgs; + if (len > 0 && i > 0) { + sg = urb->sg->sg; + buf = sg_dma_address(sg); + + /* urb->transfer_buffer_length may be smaller than the + * size of the scatterlist (or vice versa) + */ + this_sg_len = min_t(int, sg_dma_len(sg), len); + } else { + sg = NULL; + buf = urb->transfer_dma; + this_sg_len = len; + } if (is_input) token |= (1 /* "in" */ << 8); @@ -675,7 +690,9 @@ qh_urb_transaction ( for (;;) { int this_qtd_len; - this_qtd_len = qtd_fill(ehci, qtd, buf, len, token, maxpacket); + this_qtd_len = qtd_fill(ehci, qtd, buf, this_sg_len, token, + maxpacket); + this_sg_len -= this_qtd_len; len -= this_qtd_len; buf += this_qtd_len; @@ -691,8 +708,13 @@ qh_urb_transaction ( if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0) token ^= QTD_TOGGLE; - if (likely (len <= 0)) - break; + if (likely(this_sg_len <= 0)) { + if (--i <= 0 || len <= 0) + break; + sg = sg_next(sg); + buf = sg_dma_address(sg); + this_sg_len = min_t(int, sg_dma_len(sg), len); + } qtd_prev = qtd; qtd = ehci_qtd_alloc (ehci, flags); |