RE: [PATCH 1/2] dmaengine: fsl-edma: add dma memcpy support
From: Yao Yuan
Date: Wed Feb 11 2015 - 03:21:17 EST
Hi Stefan,
Thanks for your test.
Yes, it's not a huge number.
The number is always very small especially when the "test_buf_size" is small.
For dmatest tool, the measure transmission time is far greater than the actual transmission time.
So the number is small. In fact, the DMA with memory copy mode is very fast.
Best Regards,
Yuan Yao
> -----Original Message-----
> From: linux-arm-kernel [mailto:linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx]
> On Behalf Of Stefan Agner
> Sent: Friday, January 30, 2015 8:39 PM
> To: Lu Jingchang-B35083
> Cc: vinod.koul@xxxxxxxxx; dmaengine@xxxxxxxxxxxxxxx;
> dan.j.williams@xxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-arm-
> kernel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH 1/2] dmaengine: fsl-edma: add dma memcpy support
>
> On 2014-12-30 09:41, Jingchang Lu wrote:
> > This adds the memory copy capability support, the memcpy functionality
> > needs to configure the DMAMUX of the channel with the always on slave
> > id.
>
> Hi Jingchang,
>
> I run some tests on v3.19-rc6 with this patches applied on Vybrid SoC
> VF500 and VF610.
>
> On VF500 clocked at 400MHz I get this numbers:
> # insmod dmatest.ko max_channels=1 iterations=100 run=1 [ 616.809594]
> dmatest: Started 1 threads using dma0chan0 [ 617.293498] dmatest:
> dma0chan0-copy0: summary 100 tests, 0 failures
> 209 iops 1613 KB/s (0)
>
> In contrast, on a VF610 clocked at 500MHz I get this:
> # insmod dmatest.ko max_channels=1 iterations=100 run=1 [ 154.203290]
> dmatest: Started 1 threads using dma0chan4 [ 154.614225] dmatest:
> dma0chan4-copy0: summary 100 tests, 0 failures
> 246 iops 2002 KB/s (0)
>
> Not that huge numbers, but I guess this is what the hardware can deliver... Did
> you run some performance tests?
>
> But generally, looks good.
>
> Tested-by: Stefan Agner <stefan@xxxxxxxx>
>
> >
> > Signed-off-by: Jingchang Lu <jingchang.lu@xxxxxxxxxxxxx>
> > ---
> > drivers/dma/fsl-edma.c | 63
> > ++++++++++++++++++++++++++++++++++++++++++++++++--
> > 1 file changed, 61 insertions(+), 2 deletions(-)
> >
> > diff --git a/drivers/dma/fsl-edma.c b/drivers/dma/fsl-edma.c index
> > 09e2842..e0bd517 100644
> > --- a/drivers/dma/fsl-edma.c
> > +++ b/drivers/dma/fsl-edma.c
> > @@ -110,6 +110,8 @@
> > #define EDMAMUX_CHCFG_ENBL 0x80
> > #define EDMAMUX_CHCFG_SOURCE(n) ((n) & 0x3F)
> >
> > +#define SLAVE_ID_ALWAYSON 63 /* the always on slave id */
> > +
> > #define DMAMUX_NR 2
> >
> > #define FSL_EDMA_BUSWIDTHS BIT(DMA_SLAVE_BUSWIDTH_1_BYTE) |
> \
> > @@ -147,6 +149,7 @@ struct fsl_edma_slave_config { struct
> > fsl_edma_chan {
> > struct virt_dma_chan vchan;
> > enum dma_status status;
> > + u32 slave_id;
> > struct fsl_edma_engine *edma;
> > struct fsl_edma_desc *edesc;
> > struct fsl_edma_slave_config fsc;
> > @@ -637,6 +640,45 @@ static struct dma_async_tx_descriptor
> > *fsl_edma_prep_slave_sg(
> > return vchan_tx_prep(&fsl_chan->vchan, &fsl_desc->vdesc, flags); }
> >
> > +static struct dma_async_tx_descriptor * fsl_edma_prep_memcpy(struct
> > +dma_chan *chan, dma_addr_t dst,
> > + dma_addr_t src, size_t len, unsigned long tx_flags) {
> > + struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
> > + struct fsl_edma_desc *fsl_desc;
> > + u16 soff, doff, attr;
> > +
> > + /*
> > + * use 4-bytes data transfer size if all is 4-bytes aligned,
> > + * else 2-bytes data transfer size of all is 2-bytes aligned,
> > + * otherwise 1-byte tranfer size.
> > + */
> > + if (src & 0x1 || dst & 0x1 || len & 0x1) {
> > + attr = EDMA_TCD_ATTR_SSIZE_8BIT |
> EDMA_TCD_ATTR_DSIZE_8BIT;
> > + soff = 0x1;
> > + doff = 0x1;
> > + } else if (src & 0x2 || dst & 0x2 || len & 0x2) {
> > + attr = EDMA_TCD_ATTR_SSIZE_16BIT |
> EDMA_TCD_ATTR_DSIZE_16BIT;
> > + soff = 0x2;
> > + doff = 0x2;
> > + } else {
> > + attr = EDMA_TCD_ATTR_SSIZE_32BIT |
> EDMA_TCD_ATTR_DSIZE_32BIT;
> > + soff = 0x4;
> > + doff = 0x4;
> > + }
> > +
> > + fsl_desc = fsl_edma_alloc_desc(fsl_chan, 1);
> > + if (!fsl_desc)
> > + return NULL;
> > + fsl_desc->iscyclic = false;
> > +
> > + fsl_edma_fill_tcd(fsl_desc->tcd[0].vtcd, src, dst, attr, soff, len,
> > + 0, 1, 1, doff, 0, true, true, false);
> > +
> > + return vchan_tx_prep(&fsl_chan->vchan, &fsl_desc->vdesc, tx_flags);
> > +
> > +}
> > +
> > static void fsl_edma_xfer_desc(struct fsl_edma_chan *fsl_chan) {
> > struct virt_dma_desc *vdesc;
> > @@ -735,6 +777,7 @@ static struct dma_chan *fsl_edma_xlate(struct
> > of_phandle_args *dma_spec, {
> > struct fsl_edma_engine *fsl_edma = ofdma->of_dma_data;
> > struct dma_chan *chan, *_chan;
> > + struct fsl_edma_chan *fsl_chan;
> > unsigned long chans_per_mux = fsl_edma->n_chans / DMAMUX_NR;
> >
> > if (dma_spec->args_count != 2)
> > @@ -748,8 +791,10 @@ static struct dma_chan *fsl_edma_xlate(struct
> > of_phandle_args *dma_spec,
> > chan = dma_get_slave_channel(chan);
> > if (chan) {
> > chan->device->privatecnt++;
> > - fsl_edma_chan_mux(to_fsl_edma_chan(chan),
> > - dma_spec->args[1], true);
> > + fsl_chan = to_fsl_edma_chan(chan);
> > + fsl_chan->slave_id = dma_spec->args[1];
> > + fsl_edma_chan_mux(fsl_chan, fsl_chan-
> >slave_id,
> > + true);
> > mutex_unlock(&fsl_edma->fsl_edma_mutex);
> > return chan;
> > }
> > @@ -763,6 +808,17 @@ static int fsl_edma_alloc_chan_resources(struct
> > dma_chan *chan)
> > {
> > struct fsl_edma_chan *fsl_chan = to_fsl_edma_chan(chan);
> >
> > + /*
> > + * If the slave id of the channel DMAMUX is not set yet,
> > + * this could happy when the channel is requested by the
> > + * dma_request_channel() for memory copy purpose instead
> > + * of by dts binding, then configure the DMAMUX with the
> > + * always on slave id.
> > + */
> > + if (fsl_chan->slave_id == 0) {
> > + fsl_chan->slave_id = SLAVE_ID_ALWAYSON;
> > + fsl_edma_chan_mux(fsl_chan, fsl_chan->slave_id, true);
> > + }
> > fsl_chan->tcd_pool = dma_pool_create("tcd_pool", chan->device-
> >dev,
> > sizeof(struct fsl_edma_hw_tcd),
> > 32, 0);
> > @@ -778,6 +834,7 @@ static void fsl_edma_free_chan_resources(struct
> > dma_chan *chan)
> > spin_lock_irqsave(&fsl_chan->vchan.lock, flags);
> > fsl_edma_disable_request(fsl_chan);
> > fsl_edma_chan_mux(fsl_chan, 0, false);
> > + fsl_chan->slave_id = 0;
> > fsl_chan->edesc = NULL;
> > vchan_get_all_descriptors(&fsl_chan->vchan, &head);
> > spin_unlock_irqrestore(&fsl_chan->vchan.lock, flags); @@ -903,6
> > +960,7 @@ static int fsl_edma_probe(struct platform_device *pdev)
> > dma_cap_set(DMA_PRIVATE, fsl_edma->dma_dev.cap_mask);
> > dma_cap_set(DMA_SLAVE, fsl_edma->dma_dev.cap_mask);
> > dma_cap_set(DMA_CYCLIC, fsl_edma->dma_dev.cap_mask);
> > + dma_cap_set(DMA_MEMCPY, fsl_edma->dma_dev.cap_mask);
> >
> > fsl_edma->dma_dev.dev = &pdev->dev;
> > fsl_edma->dma_dev.device_alloc_chan_resources
> > @@ -912,6 +970,7 @@ static int fsl_edma_probe(struct platform_device
> *pdev)
> > fsl_edma->dma_dev.device_tx_status = fsl_edma_tx_status;
> > fsl_edma->dma_dev.device_prep_slave_sg =
> fsl_edma_prep_slave_sg;
> > fsl_edma->dma_dev.device_prep_dma_cyclic =
> fsl_edma_prep_dma_cyclic;
> > + fsl_edma->dma_dev.device_prep_dma_memcpy =
> fsl_edma_prep_memcpy;
> > fsl_edma->dma_dev.device_config = fsl_edma_slave_config;
> > fsl_edma->dma_dev.device_pause = fsl_edma_pause;
> > fsl_edma->dma_dev.device_resume = fsl_edma_resume;
>
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