From: Vikram Pandita <[email protected]> This patch enables the DMA mode1 RX support. This feature is enabled based on the short_not_ok flag passed from gadget drivers.
This will result in a thruput performance gain of around 40% for USB mass-storage/mtp use cases. Based on Original work by Anand Gadiyar <[email protected]> on 2.6.35 kernel Change-Id: I9b3a7cae73b63e86128d2caf4cdd67ab77556e75 Signed-off-by: Moiz Sonasath <[email protected]> Signed-off-by: Vikram Pandita <[email protected]> --- V1 - initial drop V2 - fixed whitespace issues as per Sergei Shtylyov<[email protected]> comments drivers/usb/musb/musb_gadget.c | 68 ++++++++++++++++++++++++--------------- 1 files changed, 42 insertions(+), 26 deletions(-) diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c index 6aeb363..4a1432e 100644 --- a/drivers/usb/musb/musb_gadget.c +++ b/drivers/usb/musb/musb_gadget.c @@ -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 for RX transfers only for mass-storage + * use-case, based on short_not_ok flag which 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 +727,40 @@ 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, -- 1.7.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
