From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [PATCH 2/2] dmaengine: cppi41: Add basic PM runtime support Date: Mon, 22 Aug 2016 12:11:52 +0530 Message-ID: <20160822064152.GP2890@localhost> References: <20160819225940.12653-1-tony@atomide.com> <20160819225940.12653-3-tony@atomide.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20160819225940.12653-3-tony-4v6yS6AI5VpBDgjK7y7TUQ@public.gmane.org> Sender: linux-usb-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Tony Lindgren Cc: Dan Williams , Bin Liu , Daniel Mack , Felipe Balbi , George Cherian , Peter Ujfalusi , Sebastian Andrzej Siewior , dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-omap-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-omap@vger.kernel.org On Fri, Aug 19, 2016 at 03:59:40PM -0700, Tony Lindgren wrote: > Let's keep the device enabled between cppi41_dma_issue_pending() > and dmaengine_desc_get_callback_invoke() and rely on the PM runtime > autoidle timeout elsewhere. > > As the PM runtime is for whole device, not for each channel, > we need to queue pending transfers if the device is PM runtime > suspended. Then we start the pending transfers in PM runtime > resume. > > Signed-off-by: Tony Lindgren > --- > drivers/dma/cppi41.c | 104 ++++++++++++++++++++++++++++++++++++++++++++++++--- > 1 file changed, 99 insertions(+), 5 deletions(-) > > diff --git a/drivers/dma/cppi41.c b/drivers/dma/cppi41.c > index 66b84fe..ce8739f 100644 > --- a/drivers/dma/cppi41.c > +++ b/drivers/dma/cppi41.c > @@ -108,6 +108,8 @@ struct cppi41_channel { > unsigned td_queued:1; > unsigned td_seen:1; > unsigned td_desc_seen:1; > + > + struct list_head node; /* Node for pending list */ > }; > > struct cppi41_desc { > @@ -146,6 +148,9 @@ struct cppi41_dd { > const struct chan_queues *queues_tx; > struct chan_queues td_queue; > > + struct list_head pending; /* Pending queued transfers */ > + spinlock_t lock; /* Lock for pending list */ > + > /* context for suspend/resume */ > unsigned int dma_tdfdq; > }; > @@ -332,6 +337,10 @@ static irqreturn_t cppi41_irq(int irq, void *data) > c->residue = pd_trans_len(c->desc->pd6) - len; > dma_cookie_complete(&c->txd); > dmaengine_desc_get_callback_invoke(&c->txd, NULL); > + > + /* Paired with cppi41_dma_issue_pending */ > + pm_runtime_mark_last_busy(cdd->ddev.dev); > + pm_runtime_put_autosuspend(cdd->ddev.dev); > } > } > return IRQ_HANDLED; > @@ -349,6 +358,12 @@ static dma_cookie_t cppi41_tx_submit(struct dma_async_tx_descriptor *tx) > static int cppi41_dma_alloc_chan_resources(struct dma_chan *chan) > { > struct cppi41_channel *c = to_cpp41_chan(chan); > + struct cppi41_dd *cdd = c->cdd; > + int error; > + > + error = pm_runtime_get_sync(cdd->ddev.dev); This will be problematic. The alloc callback are not supposed to sleep, so we cannot use a _sync() call here :( This is explicitly documented in Documentation/dmaengine/provider.txt > + if (error < 0) > + return error; > > dma_cookie_init(chan); > dma_async_tx_descriptor_init(&c->txd, chan); > @@ -357,11 +372,26 @@ static int cppi41_dma_alloc_chan_resources(struct dma_chan *chan) > if (!c->is_tx) > cppi_writel(c->q_num, c->gcr_reg + RXHPCRA0); > > + pm_runtime_mark_last_busy(cdd->ddev.dev); > + pm_runtime_put_autosuspend(cdd->ddev.dev); > + > return 0; > } > > static void cppi41_dma_free_chan_resources(struct dma_chan *chan) > { > + struct cppi41_channel *c = to_cpp41_chan(chan); > + struct cppi41_dd *cdd = c->cdd; > + int error; > + > + error = pm_runtime_get_sync(cdd->ddev.dev); same applies here too -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html