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usb: musb: Enable DMA mode1 RX for transfers without short packets 

This patch enables DMA mode1 for the RX path when we know
there won't be any short packets. We check that by looking
into the short_no_ok flag, if it's true we enable mode1, otherwise
we use mode0 to transfer the data.

This will result in a throughput performance gain of around
40% for USB mass-storage/mtp use cases.

[ balbi@ti.com : updated commit log and code comments slightly ]

Signed-off-by: Anand Gadiyar <gadiyar@ti.com>
Signed-off-by: Moiz Sonasath <m-sonasath@ti.com>
Signed-off-by: Vikram Pandita <vikram.pandita@ti.com>
Tested-by: Vikram Pandita <vikram.pandita@ti.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
This commit is contained in:
Anand Gadiyar 2011-07-19 22:11:58 -07:00 committed by Felipe Balbi
parent b3c3dc2236
commit 0ae52d5458
1 changed files with 43 additions and 26 deletions
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69
drivers/usb/musb/musb_gadget.c
View File

@ -634,6 +634,7 @@ static void rxstate(struct musb *musb, struct musb_request *req)
u16 len;
u16 csr = musb_readw(epio, MUSB_RXCSR);
struct musb_hw_ep *hw_ep = &musb->endpoints[epnum];
u8 use_mode_1;
if (hw_ep->is_shared_fifo)
musb_ep = &hw_ep->ep_in;
@ -683,6 +684,18 @@ static void rxstate(struct musb *musb, struct musb_request *req)
if (csr & MUSB_RXCSR_RXPKTRDY) {
len = musb_readw(epio, MUSB_RXCOUNT);
/*
* Enable Mode 1 on RX transfers only when short_not_ok flag
* is set. Currently short_not_ok flag is set only from
* file_storage and f_mass_storage drivers
*/
if (request->short_not_ok && len == musb_ep->packet_sz)
use_mode_1 = 1;
else
use_mode_1 = 0;
if (request->actual < request->length) {
#ifdef CONFIG_USB_INVENTRA_DMA
if (is_buffer_mapped(req)) {
@ -714,37 +727,41 @@ static void rxstate(struct musb *musb, struct musb_request *req)
* then becomes usable as a runtime "use mode 1" hint...
*/
csr |= MUSB_RXCSR_DMAENAB;
#ifdef USE_MODE1
csr |= MUSB_RXCSR_AUTOCLEAR;
/* csr |= MUSB_RXCSR_DMAMODE; */
/* this special sequence (enabling and then
* disabling MUSB_RXCSR_DMAMODE) is required
* to get DMAReq to activate
*/
musb_writew(epio, MUSB_RXCSR,
csr | MUSB_RXCSR_DMAMODE);
#else
if (!musb_ep->hb_mult &&
musb_ep->hw_ep->rx_double_buffered)
/* Experimental: Mode1 works with mass storage use cases */
if (use_mode_1) {
csr |= MUSB_RXCSR_AUTOCLEAR;
#endif
musb_writew(epio, MUSB_RXCSR, csr);
musb_writew(epio, MUSB_RXCSR, csr);
csr |= MUSB_RXCSR_DMAENAB;
musb_writew(epio, MUSB_RXCSR, csr);
/*
* this special sequence (enabling and then
* disabling MUSB_RXCSR_DMAMODE) is required
* to get DMAReq to activate
*/
musb_writew(epio, MUSB_RXCSR,
csr | MUSB_RXCSR_DMAMODE);
musb_writew(epio, MUSB_RXCSR, csr);
} else {
if (!musb_ep->hb_mult &&
musb_ep->hw_ep->rx_double_buffered)
csr |= MUSB_RXCSR_AUTOCLEAR;
csr |= MUSB_RXCSR_DMAENAB;
musb_writew(epio, MUSB_RXCSR, csr);
}
if (request->actual < request->length) {
int transfer_size = 0;
#ifdef USE_MODE1
transfer_size = min(request->length - request->actual,
channel->max_len);
#else
transfer_size = min(request->length - request->actual,
(unsigned)len);
#endif
if (transfer_size <= musb_ep->packet_sz)
musb_ep->dma->desired_mode = 0;
else
if (use_mode_1) {
transfer_size = min(request->length - request->actual,
channel->max_len);
musb_ep->dma->desired_mode = 1;
} else {
transfer_size = min(request->length - request->actual,
(unsigned)len);
musb_ep->dma->desired_mode = 0;
}
use_dma = c->channel_program(
channel,