On 5/23/2014 6:58 PM, Daniel Mack wrote:
On 05/23/2014 03:18 PM, George Cherian wrote:
On 5/23/2014 3:01 PM, Daniel Mack wrote:
Before accessing any of an endpoint's CSR registers, make sure the
correct endpoint is selected. Otherwise, data read from or written to
the registers is likely to affect the wrong endpoint as long as the
connected device has more than one endpoint.
This, of course, leads to all sorts of strange effects such as stream
starvation and driver internal state machine confusion due to spurious
interrupts.
Signed-off-by: Daniel Mack <zonque@xxxxxxxxx>
---
drivers/usb/musb/musb_cppi41.c | 17 ++++++++++++++---
1 file changed, 14 insertions(+), 3 deletions(-)
diff --git a/drivers/usb/musb/musb_cppi41.c b/drivers/usb/musb/musb_cppi41.c
index a11bbb6..db497dd 100644
--- a/drivers/usb/musb/musb_cppi41.c
+++ b/drivers/usb/musb/musb_cppi41.c
@@ -58,14 +58,17 @@ struct cppi41_dma_controller {
static void save_rx_toggle(struct cppi41_dma_channel *cppi41_channel)
{
+ struct musb_hw_ep *hw_ep = cppi41_channel->hw_ep;
+ struct musb *musb = hw_ep->musb;
u16 csr;
u8 toggle;
if (cppi41_channel->is_tx)
return;
- if (!is_host_active(cppi41_channel->controller->musb))
+ if (!is_host_active(musb))
return;
+ musb_ep_select(musb->mregs, hw_ep->epnum);
save_rx_toggle is called from cppi41_configure_channel as part of
channel_program() from musb_host_rx()
and musb_ep_program(). Both these functions call musb_ep_select() before
calling channel_program().
Both musb_ep_program() and musb_host_rx() are called with IRQ's disabled.
Still do we need this musb_ep_select() in save_rx_toggle? Or am I confused?
No, you're right. It seems not necessary here.
@@ -173,6 +180,7 @@ static void cppi41_trans_done(struct cppi41_dma_channel *cppi41_channel)
dma_async_issue_pending(dc);
if (!cppi41_channel->is_tx) {
+ musb_ep_select(musb->mregs, hw_ep->epnum);
Since in update_rx_toggle () we did musb_epe_select(), do we really it
again here?
I'd say so, because cppi41_trans_done() may be called from a work
tasklet or hrtimer callback. In such cases, another endpoint might have
been selected.
Yes Correct!!!
@@ -565,6 +574,8 @@ static int cppi41_dma_channel_abort(struct dma_channel *channel)
if (cppi41_channel->channel.status == MUSB_DMA_STATUS_FREE)
return 0;
musb_ep_select is done before calling channel_abort.
Right, thanks for spotting this. I'll drop it in v3.
Thanks,
Daniel
--
-George
--
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