> -----Original Message----- > From: Sascha Hauer [mailto:s.hauer@xxxxxxxxxxxxxx] > Sent: 2018年7月13日 14:16 > To: Robin Gong <yibin.gong@xxxxxxx> > Cc: vkoul@xxxxxxxxxx; dan.j.williams@xxxxxxxxx; shawnguo@xxxxxxxxxx; Fabio > Estevam <fabio.estevam@xxxxxxx>; linux@xxxxxxxxxxxxxxx; > linux-arm-kernel@xxxxxxxxxxxxxxxxxxx; kernel@xxxxxxxxxxxxxx; > dmaengine@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; dl-linux-imx > <linux-imx@xxxxxxx> > Subject: Re: [PATCH v2 2/3] dmaengine: imx-sdma: add memcpy interface > > On Fri, Jul 13, 2018 at 09:08:46PM +0800, Robin Gong wrote: > > Add MEMCPY capability for imx-sdma driver. > > > > Signed-off-by: Robin Gong <yibin.gong@xxxxxxx> > > --- > > drivers/dma/imx-sdma.c | 95 > > ++++++++++++++++++++++++++++++++++++++++++++++++-- > > 1 file changed, 92 insertions(+), 3 deletions(-) > > > > @@ -1318,6 +1347,63 @@ static struct sdma_desc > *sdma_transfer_init(struct sdma_channel *sdmac, > > return NULL; > > } > > > > +static struct dma_async_tx_descriptor *sdma_prep_memcpy( > > + struct dma_chan *chan, dma_addr_t dma_dst, > > + dma_addr_t dma_src, size_t len, unsigned long flags) { > > + struct sdma_channel *sdmac = to_sdma_chan(chan); > > + struct sdma_engine *sdma = sdmac->sdma; > > + int channel = sdmac->channel; > > + size_t count; > > + int i = 0, param; > > + struct sdma_buffer_descriptor *bd; > > + struct sdma_desc *desc; > > + > > + if (!chan || !len) > > + return NULL; > > + > > + dev_dbg(sdma->dev, "memcpy: %pad->%pad, len=%zu, channel=%d.\n", > > + &dma_src, &dma_dst, len, channel); > > + > > + desc = sdma_transfer_init(sdmac, DMA_MEM_TO_MEM, > > + len / SDMA_BD_MAX_CNT + 1); > > + if (!desc) > > + return NULL; > > + > > + do { > > + count = min_t(size_t, len, SDMA_BD_MAX_CNT); > > + bd = &desc->bd[i]; > > + bd->buffer_addr = dma_src; > > + bd->ext_buffer_addr = dma_dst; > > + bd->mode.count = count; > > + desc->chn_count += count; > > + /* align with sdma->dma_device.copy_align: 4bytes */ > > + bd->mode.command = 0; > > + > > + dma_src += count; > > + dma_dst += count; > > + len -= count; > > + i++; > > NACK. > > Please actually look at your code and find out where you do unaligned DMA > accesses. Hint: What happens when this loop body is executed more than > once? > > Sascha Actually internal sdma script has already take such 'align' matter like below: Burst with words if source/dest address and data length are all aligned with words, burst with Byte if not. So I will remove the comment '/* align with sdma->dma_device.copy_align: 4bytes */' In v3. Besides, I have found another bug which introduced by my virt-dma patch. Will send V3 later. > > > + > > + param = BD_DONE | BD_EXTD | BD_CONT; > > + /* last bd */ > > + if (!len) { > > + param |= BD_INTR; > > + param |= BD_LAST; > > + param &= ~BD_CONT; > > + } > > + > > + dev_dbg(sdma->dev, "entry %d: count: %zd dma: 0x%x %s%s\n", > > + i, count, bd->buffer_addr, > > + param & BD_WRAP ? "wrap" : "", > > + param & BD_INTR ? " intr" : ""); > > + > > + bd->mode.status = param; > > + } while (len); > > + > > -- > Pengutronix e.K. | > | > Industrial Linux Solutions | > https://emea01.safelinks.protection.outlook.com/?url=http%3A%2F%2Fwww. > pengutronix.de%2F&data=02%7C01%7Cyibin.gong%40nxp.com%7Cf78f9 > 91028e64b45cf7508d5e888310d%7C686ea1d3bc2b4c6fa92cd99c5c301635%7 > C0%7C0%7C636670594003030732&sdata=zyDkLHVl4VneD05f4VvaY82m > ZITkybewrXyCj2YRu%2FI%3D&reserved=0 | > Peiner Str. 6-8, 31137 Hildesheim, Germany | Phone: +49-5121-206917-0 | > Amtsgericht Hildesheim, HRA 2686 | Fax: > +49-5121-206917-5555 | ?韬{.n?????%??檩??w?{.n???Ё?撖)?骅w* jg????????G??⒏ ⒎?:+v???????? ????＂??????
