Hi,
On Mon, Nov 30, 2009 at 11:53:26AM +0100, ext Sergei Shtylyov wrote:
@@ -175,6 +182,19 @@ static int dma_channel_program(struct dm
BUG_ON(channel->status == MUSB_DMA_STATUS_UNKNOWN ||
channel->status == MUSB_DMA_STATUS_BUSY);
+ /* In version 1.4, if two DMA channels are simultaneously
+ * enabled in opposite directions, there is a chance that
+ * the DMA controller will hang. However, it is safe to
+ * have multiple DMA channels enabled in the same direction
+ * at the same time.
+ */
+ if (musb->hwvers == MUSB_HWVERS_1400) {
+ if (musb_channel->transmit && controller->rx_active)
+ return false;
+ else if (!musb_channel->transmit && controller->tx_active)
+ return false;
how about returning error code here ?
How? The channel_program() method returns zero on error, and non-zero
on sucess.
if this is on top of the mode1 support then you're wrong:
464 static void musb_ep_restart(struct musb *musb, struct musb_request *req)
465 {
466 DBG(3, "<== TX/IN request %p len %u on hw_ep%d%s\n",
467 &req->request, req->request.length, req->epnum,
468 req->ep->dma ? " (dma)" : "(pio)");
469
470 musb_ep_select(musb->mregs, req->epnum);
471
472 if (start_dma(musb, req) < 0)
473 do_pio_tx(musb, req);
474 }
and I'm assuming Anand is using that already ?? There's only one change
needed on start_dma() to actually make this work as supposed, something
like:
diff --git a/drivers/usb/musb/musb_gadget.c b/drivers/usb/musb/musb_gadget.c
index 808a432..6901cbd 100644
--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -250,8 +250,9 @@ static int start_dma(struct musb *musb, struct musb_request *req)
musb_ep->dma = dma;
- (void) cntr->channel_program(dma, packet_sz, true, req->request.dma,
- transfer_size);
+ if (cntr->channel_program(dma, packet_sz, true, req->request.dma,
+ transfer_size) < 0)
+ return -1;
DBG(4, "%s dma started (addr 0x%08x, len %u, CSR %04x)\n",
musb_ep->name, req->request.dma, transfer_size, csr);
--
balbi
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