From: Vikram Pandita <vikram.pandita@xxxxxx>
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 <gadiyar@xxxxxx> on 2.6.35 kernel
Tested on OMAP4460 Blaze board.
Signed-off-by: Moiz Sonasath <m-sonasath@xxxxxx>
Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
---
drivers/usb/musb/musb_gadget.c | 42 ++++++++++++++++++++++++++++-----------
1 files changed, 30 insertions(+), 12 deletions(-)
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 9412410..e643ec2 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -624,6 +624,7 @@ void musb_g_tx(struct musb *musb, u8 epnum)
/*
* Context: controller locked, IRQs blocked, endpoint selected
*/
+
static void rxstate(struct musb *musb, struct musb_request *req)
{
const u8 epnum = req->epnum;
@@ -634,6 +635,7 @@ 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 +685,18 @@ 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)) {
@@ -714,10 +728,13 @@ 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
+ /* Experimental: Mode1 works with mass storage use cases
+ */
+ if (use_mode_1) {
csr |= MUSB_RXCSR_AUTOCLEAR;
- /* csr |= MUSB_RXCSR_DMAMODE; */
+ 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
@@ -725,26 +742,27 @@ static void rxstate(struct musb *musb, struct musb_request *req)
*/
musb_writew(epio, MUSB_RXCSR,
csr | MUSB_RXCSR_DMAMODE);
-#else
+ musb_writew(epio, MUSB_RXCSR, csr);
+
+ } else {
if (!musb_ep->hb_mult &&
musb_ep->hw_ep->rx_double_buffered)
csr |= MUSB_RXCSR_AUTOCLEAR;
-#endif
+ csr |= MUSB_RXCSR_DMAENAB;
musb_writew(epio, MUSB_RXCSR, csr);
+ }
if (request->actual < request->length) {
int transfer_size = 0;
-#ifdef USE_MODE1
+ if (use_mode_1) {
transfer_size = min(request->length - request->actual,
channel->max_len);
-#else
+ musb_ep->dma->desired_mode = 1;
+ } 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
- musb_ep->dma->desired_mode = 1;
+ musb_ep->dma->desired_mode = 0;
+ }
use_dma = c->channel_program(
channel,
--
1.7.4.1
--
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