From: jamie@jamieiles.com (Jamie Iles) Date: Tue, 19 Apr 2011 09:55:15 +0100 Subject: [PATCH V2 7/7] dmaengine/dw_dmac: implement pause and resume in dwc_control In-Reply-To: References: Message-ID: <20110419085514.GG2820@pulham.picochip.com> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On Tue, Apr 19, 2011 at 02:02:12PM +0530, Viresh Kumar wrote: > From: Linus Walleij > > Some peripherals like amba-pl011 needs pause to be implemented in DMA controller > drivers. This also returns correct status from dwc_tx_status() in case chan is > paused. > > Signed-off-by: Linus Walleij > Signed-off-by: Viresh Kumar > --- > drivers/dma/dw_dmac.c | 25 +++++++++++++++++++++++-- > drivers/dma/dw_dmac_regs.h | 1 + > 2 files changed, 24 insertions(+), 2 deletions(-) > > diff --git a/drivers/dma/dw_dmac.c b/drivers/dma/dw_dmac.c > index c30f0ba..48d2d7e 100644 > --- a/drivers/dma/dw_dmac.c > +++ b/drivers/dma/dw_dmac.c > @@ -832,8 +832,7 @@ static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, > struct dw_desc *desc, *_desc; > LIST_HEAD(list); > > - /* Only supports DMA_TERMINATE_ALL */ > - if (cmd != DMA_TERMINATE_ALL) > + if (cmd != DMA_TERMINATE_ALL && cmd != DMA_PAUSE && cmd != DMA_RESUME) > return -ENXIO; > > /* > @@ -844,11 +843,30 @@ static int dwc_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd, > */ > spin_lock_irqsave(&dwc->lock, dwc->lflags); > > + if (cmd == DMA_RESUME) { > + if (dwc->paused) { > + channel_set_bit(dw, CH_EN, dwc->mask); > + while (!(dma_readl(dw, CH_EN) & dwc->mask)) > + cpu_relax(); > + } > + spin_unlock_irqrestore(&dwc->lock, dwc->lflags); > + return 0; > + } > + > channel_clear_bit(dw, CH_EN, dwc->mask); > > while (dma_readl(dw, CH_EN) & dwc->mask) > cpu_relax(); > > + if (cmd == DMA_PAUSE) { > + dwc->paused = true; > + spin_unlock_irqrestore(&dwc->lock, dwc->lflags); > + return 0; > + }