From mboxrd@z Thu Jan 1 00:00:00 1970 From: Vinod Koul Subject: Re: [PATCH] dmaengine: tegra-apb: Support non-flow controlled slave configuration Date: Thu, 12 Oct 2017 22:23:11 +0530 Message-ID: <20171012165310.GU30097@localhost> References: <20171003223838.31834-1-digetx@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20171003223838.31834-1-digetx-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org> Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Dmitry Osipenko Cc: Thierry Reding , Jonathan Hunter , Laxman Dewangan , dmaengine-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-tegra@vger.kernel.org On Wed, Oct 04, 2017 at 01:38:38AM +0300, Dmitry Osipenko wrote: > This allows DMA client to issue a non-flow controlled TX. In particular > it is needed for the fuse driver that reads fuse registers using APBDMA > to workaround a HW bug that results in hang when CPU and DMA perform > simultaneous access to fuse peripheral. > > Signed-off-by: Dmitry Osipenko > --- > drivers/dma/tegra20-apb-dma.c | 19 ++++++++++++++----- > 1 file changed, 14 insertions(+), 5 deletions(-) > > diff --git a/drivers/dma/tegra20-apb-dma.c b/drivers/dma/tegra20-apb-dma.c > index b9d75a54c896..a177039713a7 100644 > --- a/drivers/dma/tegra20-apb-dma.c > +++ b/drivers/dma/tegra20-apb-dma.c > @@ -353,7 +353,8 @@ static int tegra_dma_slave_config(struct dma_chan *dc, > } > > memcpy(&tdc->dma_sconfig, sconfig, sizeof(*sconfig)); > - if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID) { > + if (tdc->slave_id == TEGRA_APBDMA_SLAVE_ID_INVALID && > + sconfig->device_fc) { > if (sconfig->slave_id > TEGRA_APBDMA_CSR_REQ_SEL_MASK) > return -EINVAL; > tdc->slave_id = sconfig->slave_id; > @@ -970,8 +971,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_slave_sg( > TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT; > ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32; > > - csr |= TEGRA_APBDMA_CSR_ONCE | TEGRA_APBDMA_CSR_FLOW; > - csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT; > + csr |= TEGRA_APBDMA_CSR_ONCE ; ^^^ Checkpatch should have complained here, no space before ; please > + > + if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) { > + csr |= TEGRA_APBDMA_CSR_FLOW; > + csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT; > + } > + > if (flags & DMA_PREP_INTERRUPT) > csr |= TEGRA_APBDMA_CSR_IE_EOC; > > @@ -1110,10 +1116,13 @@ static struct dma_async_tx_descriptor *tegra_dma_prep_dma_cyclic( > TEGRA_APBDMA_AHBSEQ_WRAP_SHIFT; > ahb_seq |= TEGRA_APBDMA_AHBSEQ_BUS_WIDTH_32; > > - csr |= TEGRA_APBDMA_CSR_FLOW; > + if (tdc->slave_id != TEGRA_APBDMA_SLAVE_ID_INVALID) { > + csr |= TEGRA_APBDMA_CSR_FLOW; > + csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT; > + } > + > if (flags & DMA_PREP_INTERRUPT) > csr |= TEGRA_APBDMA_CSR_IE_EOC; > - csr |= tdc->slave_id << TEGRA_APBDMA_CSR_REQ_SEL_SHIFT; > > apb_seq |= TEGRA_APBDMA_APBSEQ_WRAP_WORD_1; > > -- > 2.14.1 > > -- > To unsubscribe from this list: send the line "unsubscribe dmaengine" in > the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org > More majordomo info at http://vger.kernel.org/majordomo-info.html -- ~Vinod