> -----Original Message----- > From: linux-omap-owner@xxxxxxxxxxxxxxx > [mailto:linux-omap-owner@xxxxxxxxxxxxxxx] On Behalf Of Kevin Hilman > Sent: Wednesday, November 10, 2010 4:18 AM > To: G, Manjunath Kondaiah > Cc: linux-omap@xxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; Cousson, Benoit; > Shilimkar, Santosh > Subject: Re: [PATCH v3 13/13] OMAP: PM: DMA: Enable runtime pm > > "G, Manjunath Kondaiah" <manjugk@xxxxxx> writes: > > > Enable runtime pm and use pm_runtime_get and pm_runtime_put > > for OMAP DMA driver. > > > > Signed-off-by: G, Manjunath Kondaiah <manjugk@xxxxxx> > > Cc: Benoit Cousson <b-cousson@xxxxxx> > > Cc: Kevin Hilman <khilman@xxxxxxxxxxxxxxxxxxx> > > Cc: Santosh Shilimkar <santosh.shilimkar@xxxxxx> > > --- > > arch/arm/plat-omap/dma.c | 13 +++++++++++++ > > 1 files changed, 13 insertions(+), 0 deletions(-) > > > > diff --git a/arch/arm/plat-omap/dma.c b/arch/arm/plat-omap/dma.c > > index 41b14b0..feac7ee 100644 > > --- a/arch/arm/plat-omap/dma.c > > +++ b/arch/arm/plat-omap/dma.c > > @@ -35,6 +35,7 @@ > > #include <linux/io.h> > > #include <linux/slab.h> > > #include <linux/delay.h> > > +#include <linux/pm_runtime.h> > > > > #include <asm/system.h> > > #include <mach/hardware.h> > > @@ -367,6 +368,8 @@ int omap_request_dma(int dev_id, const > char *dev_name, > > chan = dma_chan + free_ch; > > chan->dev_id = dev_id; > > > > + pm_runtime_get(&pd->dev); > > The _get() call is asynchronous. So if the device was actually > idled/disabled, immediately after this call it may still be > idle/disabled. When using the asynchronous versions of the API, the > device should not be touched until the driver's ->runtime_resume() > callback is called. driver runtime_resume will call omap_device_enable. How do we make we check from driver side, whether omap_device_enable execution is complete or not. > > > if (d->dev_caps & IS_WORD_16) > > p->clear_lch_regs(free_ch); > > else > > @@ -452,6 +455,7 @@ void omap_free_dma(int lch) > > omap_clear_dma(lch); > > p->clear_dma_sglist_mode(lch); > > } > > + pm_runtime_put(&pd->dev); > > spin_lock_irqsave(&dma_chan_lock, flags); > > dma_chan[lch].dev_id = -1; > > dma_chan[lch].next_lch = -1; > > @@ -819,6 +823,11 @@ static int __devinit > omap_system_dma_probe(struct platform_device *pdev) > > dma_chan_count = d->chan_count; > > dma_chan = d->chan; > > > > + /* Enable run time PM */ > > comment is redundant ok. > > > + pm_runtime_enable(&pd->dev); > > + > > + /* Accessing hw registers, get clock */ > > comment is wrong, driver doesn't know anything about clocks. > Just drop comment as it doesn't tell you anything that the following > 'get' doesn't. > > > + pm_runtime_get(&pd->dev); > > see above Re: async calls. > > > for (ch = 0; ch < dma_chan_count; ch++) { > > unsigned long flags; > > omap_clear_dma(ch); > > @@ -846,6 +855,10 @@ static int __devinit > omap_system_dma_probe(struct platform_device *pdev) > > dma_chan[0].dev_id = 0; > > dma_chan[1].dev_id = 1; > > } > > + > > + if (!omap_dma_reserve_channels) > > + pm_runtime_put(&pd->dev); > > + > > So if the reserve channels feature is used, PM is essentially disabled > for sDMA. You should add a warning here to that effect as well. I will add warning comment. -Manjunath-- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
