Hi Tony,
On Wed, Oct 2, 2019 at 6:52 PM Tony Lindgren <t...@atomide.com> wrote:
>
> * Yegor Yefremov <yegorsli...@googlemail.com> [191002 06:57]:
> > On Wed, Oct 2, 2019 at 12:03 AM Tony Lindgren <t...@atomide.com> wrote:
> > > The other way to fix this would be to just wake up cpp41 in
> > > cppi41_dma_prep_slave_sg() and return NULL so that we can
> > > have musb_ep_program() continue with PIO while cppi41 is
> > > asleep.
> > >
> > > Anyways, care to try it out and see if it fixes your issue?
> >
> > The fix is working but on the first invocation, I get this output
> > (minicom provokes the same output):
>
> > # serialtest.py -c 2 /dev/ttyUSB0 /dev/ttyUSB0
> ...
> > [ 210.940612] [<c065fc94>] (__rpm_callback) from [<c065fd60>]
> > (rpm_callback+0x20/0x80)
> > [ 210.948402] [<c065fd60>] (rpm_callback) from [<c065f7cc>]
> > (rpm_resume+0x468/0x7a0)
> > [ 210.956018] [<c065f7cc>] (rpm_resume) from [<c065fb50>]
> > (__pm_runtime_resume+0x4c/0x64)
> > [ 210.964086] [<c065fb50>] (__pm_runtime_resume) from [<bf020940>]
> > (cppi41_dma_prep_slave_sg+0x20/0xfc [cppi41])
>
> OK so that won't work, thanks for testing. Here's the alternative
> patch to try along the lines described above that just wakes up
> cppi41 and returns NULL so musb_ep_program() can continue with PIO
> until cppi41 is awake.
I'm out of the office for some weeks and don't have access to my hw.
I'll make the test as soon as I'm back.
Thanks.
Yegor
> 8< -----------------------
> diff --git a/drivers/dma/ti/cppi41.c b/drivers/dma/ti/cppi41.c
> --- a/drivers/dma/ti/cppi41.c
> +++ b/drivers/dma/ti/cppi41.c
> @@ -586,9 +586,22 @@ static struct dma_async_tx_descriptor
> *cppi41_dma_prep_slave_sg(
> enum dma_transfer_direction dir, unsigned long tx_flags, void
> *context)
> {
> struct cppi41_channel *c = to_cpp41_chan(chan);
> + struct dma_async_tx_descriptor *txd = NULL;
> + struct cppi41_dd *cdd = c->cdd;
> struct cppi41_desc *d;
> struct scatterlist *sg;
> unsigned int i;
> + int error;
> +
> + error = pm_runtime_get(cdd->ddev.dev);
> + if (error < 0) {
> + pm_runtime_put_noidle(cdd->ddev.dev);
> +
> + return NULL;
> + }
> +
> + if (cdd->is_suspended)
> + goto err_out_not_ready;
>
> d = c->desc;
> for_each_sg(sgl, sg, sg_len, i) {
> @@ -611,7 +624,13 @@ static struct dma_async_tx_descriptor
> *cppi41_dma_prep_slave_sg(
> d++;
> }
>
> - return &c->txd;
> + txd = &c->txd;
> +
> +err_out_not_ready:
> + pm_runtime_mark_last_busy(cdd->ddev.dev);
> + pm_runtime_put_autosuspend(cdd->ddev.dev);
> +
> + return txd;
> }
>
> static void cppi41_compute_td_desc(struct cppi41_desc *d)
> --
> 2.23.0
