On MUSB:IP rev RTL1.8 and above(OMAP3630, OMAP4),
DMA addresses have to be word aligned.
g-ether gadget passes unaligned buffers to the controller
For such buffers, dma fails and a fall back mechanism of interrupt
mode is used
Validated on Zoom3 with g-ether diver
Signed-off-by: Anand Gadiyar <gadiyar@xxxxxx>
Signed-off-by: Vikram Pandita <vikram.pandita@xxxxxx>
Cc: Maulik Mankad <x0082077@xxxxxx>
Cc: Nilkesh Patra <nilkesh.patra@xxxxxx>
Cc: Felipe Balbi <felipe.balbi@xxxxxxxxx>
---
drivers/usb/musb/musb_gadget.c | 9 ++++++++-
drivers/usb/musb/musbhsdma.c | 11 +++++++++++
2 files changed, 19 insertions(+), 1 deletions(-)
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index cbcf14a..7ad3571 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -681,8 +681,15 @@ static void rxstate(struct musb *musb, struct musb_request *req)
transfer_size);
}
- if (use_dma)
+ if (use_dma) {
return;
+ } else {
+ /* Need to clear DMAENAB for the
+ * backup PIO mode transfer to work
+ */
+ csr &= ~MUSB_RXCSR_DMAENAB;
+ musb_writew(epio, MUSB_RXCSR, csr);
+ }
}
#endif /* Mentor's DMA */
diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c
index a237550..f118ae2 100644
--- a/drivers/usb/musb/musbhsdma.c
+++ b/drivers/usb/musb/musbhsdma.c
@@ -166,6 +166,8 @@ static int dma_channel_program(struct dma_channel *channel,
dma_addr_t dma_addr, u32 len)
{
struct musb_dma_channel *musb_channel = channel->private_data;
+ struct musb_dma_controller *controller = musb_channel->controller;
+ struct musb *musb = controller->private_data;
DBG(2, "ep%d-%s pkt_sz %d, dma_addr 0x%x length %d, mode %d\n",
musb_channel->epnum,
@@ -175,6 +177,15 @@ static int dma_channel_program(struct dma_channel *channel,
BUG_ON(channel->status == MUSB_DMA_STATUS_UNKNOWN ||
channel->status == MUSB_DMA_STATUS_BUSY);
+ /* On MUSB:RTL1.8 and above, DMA has to be word aligned */
+ if ((dma_addr % 4) &&
+ (musb->hwvers >= MUSB_HWVERS_1800)) {
+ /* Fail DMA for unaligned buffers:
+ * Use PIO for such buffers
+ */
+ return false;
+ }
+
channel->actual_len = 0;
musb_channel->start_addr = dma_addr;
musb_channel->len = len;
--
1.6.6.rc0.66.ge160d
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