diff mbox

[v2,2/3] dmaengine: imx-sdma: add memcpy interface

Message ID 1531487327-21879-3-git-send-email-yibin.gong@nxp.com (mailing list archive)
State Changes Requested
Headers show

Commit Message

Robin Gong July 13, 2018, 1:08 p.m. UTC 
Add MEMCPY capability for imx-sdma driver.

Signed-off-by: Robin Gong <yibin.gong@nxp.com>
---
 drivers/dma/imx-sdma.c | 95 ++++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 92 insertions(+), 3 deletions(-)

Comments

Sascha Hauer July 13, 2018, 6:16 a.m. UTC | #1 
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@nxp.com>
> ---
>  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

> +
> +		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);
> +
Robin Gong July 20, 2018, 9:40 a.m. UTC | #2 
> -----Original Message-----

> From: Sascha Hauer [mailto:s.hauer@pengutronix.de]

> Sent: 2018年7月13日 14:16

> To: Robin Gong <yibin.gong@nxp.com>

> Cc: vkoul@kernel.org; dan.j.williams@intel.com; shawnguo@kernel.org; Fabio

> Estevam <fabio.estevam@nxp.com>; linux@armlinux.org.uk;

> linux-arm-kernel@lists.infradead.org; kernel@pengutronix.de;

> dmaengine@vger.kernel.org; linux-kernel@vger.kernel.org; dl-linux-imx

> <linux-imx@nxp.com>

> 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@nxp.com>

> > ---

> >  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);

> > +

> 

> --

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Sascha Hauer Aug. 6, 2018, 8:53 a.m. UTC | #3 
On Fri, Jul 20, 2018 at 09:40:51AM +0000, Robin Gong wrote:
> > -----Original Message-----
> > From: Sascha Hauer [mailto:s.hauer@pengutronix.de]
> > Sent: 2018年7月13日 14:16
> > To: Robin Gong <yibin.gong@nxp.com>
> > Cc: vkoul@kernel.org; dan.j.williams@intel.com; shawnguo@kernel.org; Fabio
> > Estevam <fabio.estevam@nxp.com>; linux@armlinux.org.uk;
> > linux-arm-kernel@lists.infradead.org; kernel@pengutronix.de;
> > dmaengine@vger.kernel.org; linux-kernel@vger.kernel.org; dl-linux-imx
> > <linux-imx@nxp.com>
> > 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@nxp.com>
> > > ---
> > >  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.

If that's the case why did you add the DMAENGINE_ALIGN_4_BYTES flag in the
first place?

Also, if the SDMA script falls back to byte copy when necessary, doing
so probably has performance impacts, so I wonder why you don't just cut
'count' to something that is four byte aligned.

Sascha
diff mbox

Patch

diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
index e3d5e73..ef50f2c 100644
--- a/drivers/dma/imx-sdma.c
+++ b/drivers/dma/imx-sdma.c
@@ -342,6 +342,7 @@  struct sdma_desc {
  * @pc_from_device:	script address for those device_2_memory
  * @pc_to_device:	script address for those memory_2_device
  * @device_to_device:	script address for those device_2_device
+ * @pc_to_pc:		script address for those memory_2_memory
  * @flags:		loop mode or not
  * @per_address:	peripheral source or destination address in common case
  *                      destination address in p_2_p case
@@ -367,6 +368,7 @@  struct sdma_channel {
 	enum dma_slave_buswidth		word_size;
 	unsigned int			pc_from_device, pc_to_device;
 	unsigned int			device_to_device;
+	unsigned int                    pc_to_pc;
 	unsigned long			flags;
 	dma_addr_t			per_address, per_address2;
 	unsigned long			event_mask[2];
@@ -869,14 +871,16 @@  static void sdma_get_pc(struct sdma_channel *sdmac,
 	 * These are needed once we start to support transfers between
 	 * two peripherals or memory-to-memory transfers
 	 */
-	int per_2_per = 0;
+	int per_2_per = 0, emi_2_emi = 0;
 
 	sdmac->pc_from_device = 0;
 	sdmac->pc_to_device = 0;
 	sdmac->device_to_device = 0;
+	sdmac->pc_to_pc = 0;
 
 	switch (peripheral_type) {
 	case IMX_DMATYPE_MEMORY:
+		emi_2_emi = sdma->script_addrs->ap_2_ap_addr;
 		break;
 	case IMX_DMATYPE_DSP:
 		emi_2_per = sdma->script_addrs->bp_2_ap_addr;
@@ -949,6 +953,7 @@  static void sdma_get_pc(struct sdma_channel *sdmac,
 	sdmac->pc_from_device = per_2_emi;
 	sdmac->pc_to_device = emi_2_per;
 	sdmac->device_to_device = per_2_per;
+	sdmac->pc_to_pc = emi_2_emi;
 }
 
 static int sdma_load_context(struct sdma_channel *sdmac)
@@ -965,6 +970,8 @@  static int sdma_load_context(struct sdma_channel *sdmac)
 		load_address = sdmac->pc_from_device;
 	else if (sdmac->direction == DMA_DEV_TO_DEV)
 		load_address = sdmac->device_to_device;
+	else if (sdmac->direction == DMA_MEM_TO_MEM)
+		load_address = sdmac->pc_to_pc;
 	else
 		load_address = sdmac->pc_to_device;
 
@@ -1214,10 +1221,28 @@  static int sdma_alloc_chan_resources(struct dma_chan *chan)
 {
 	struct sdma_channel *sdmac = to_sdma_chan(chan);
 	struct imx_dma_data *data = chan->private;
+	struct imx_dma_data mem_data;
 	int prio, ret;
 
-	if (!data)
-		return -EINVAL;
+	/*
+	 * MEMCPY may never setup chan->private by filter function such as
+	 * dmatest, thus create 'struct imx_dma_data mem_data' for this case.
+	 * Please note in any other slave case, you have to setup chan->private
+	 * with 'struct imx_dma_data' in your own filter function if you want to
+	 * request dma channel by dma_request_channel() rather than
+	 * dma_request_slave_channel(). Othwise, 'MEMCPY in case?' will appear
+	 * to warn you to correct your filter function.
+	 */
+	if (!data) {
+		dev_dbg(sdmac->sdma->dev, "MEMCPY in case?\n");
+		mem_data.priority = 2;
+		mem_data.peripheral_type = IMX_DMATYPE_MEMORY;
+		mem_data.dma_request = 0;
+		mem_data.dma_request2 = 0;
+		data = &mem_data;
+
+		sdma_get_pc(sdmac, IMX_DMATYPE_MEMORY);
+	}
 
 	switch (data->priority) {
 	case DMA_PRIO_HIGH:
@@ -1307,6 +1332,10 @@  static struct sdma_desc *sdma_transfer_init(struct sdma_channel *sdmac,
 	if (sdma_alloc_bd(desc))
 		goto err_desc_out;
 
+	/* No slave_config called in MEMCPY case, so do here */
+	if (direction == DMA_MEM_TO_MEM)
+		sdma_config_ownership(sdmac, false, true, false);
+
 	if (sdma_load_context(sdmac))
 		goto err_desc_out;
 
@@ -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++;
+
+		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);
+
+	return vchan_tx_prep(&sdmac->vc, &desc->vd, flags);
+}
+
 static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
 		struct dma_chan *chan, struct scatterlist *sgl,
 		unsigned int sg_len, enum dma_transfer_direction direction,
@@ -1903,6 +1989,7 @@  static int sdma_probe(struct platform_device *pdev)
 
 	dma_cap_set(DMA_SLAVE, sdma->dma_device.cap_mask);
 	dma_cap_set(DMA_CYCLIC, sdma->dma_device.cap_mask);
+	dma_cap_set(DMA_MEMCPY, sdma->dma_device.cap_mask);
 
 	INIT_LIST_HEAD(&sdma->dma_device.channels);
 	/* Initialize channel parameters */
@@ -1969,8 +2056,10 @@  static int sdma_probe(struct platform_device *pdev)
 	sdma->dma_device.dst_addr_widths = SDMA_DMA_BUSWIDTHS;
 	sdma->dma_device.directions = SDMA_DMA_DIRECTIONS;
 	sdma->dma_device.residue_granularity = DMA_RESIDUE_GRANULARITY_SEGMENT;
+	sdma->dma_device.device_prep_dma_memcpy = sdma_prep_memcpy;
 	sdma->dma_device.device_issue_pending = sdma_issue_pending;
 	sdma->dma_device.dev->dma_parms = &sdma->dma_parms;
+	sdma->dma_device.copy_align = DMAENGINE_ALIGN_4_BYTES;
 	dma_set_max_seg_size(sdma->dma_device.dev, SDMA_BD_MAX_CNT);
 
 	platform_set_drvdata(pdev, sdma);