Re: [PATCH v1] dma: imx-sdma: add support for sdma memory copy

From: Shevchenko, Andriy
Date: Thu Apr 17 2014 - 06:25:50 EST


On Thu, 2014-04-17 at 18:01 +0800, Robin Gong wrote:
> add "device_prep_dma_memcpy" and "device_prep_dma_sg" for memory copy by sdma.
>
> Signed-off-by: Robin Gong <b38343@xxxxxxxxxxxxx>
> ---
> drivers/dma/imx-sdma.c | 188 +++++++++++++++++++++++++++++++++++++++++------
> 1 files changed, 164 insertions(+), 24 deletions(-)
>
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index 4e79183..2a97e03 100644
> --- a/drivers/dma/imx-sdma.c
> +++ b/drivers/dma/imx-sdma.c
> @@ -229,6 +229,7 @@ struct sdma_context_data {
> } __attribute__ ((packed));
>
> #define NUM_BD (int)(PAGE_SIZE / sizeof(struct sdma_buffer_descriptor))
> +#define SDMA_BD_MAX_CNT (0xfffc) /* align with 4 bytes */
>
> struct sdma_engine;
>
> @@ -260,6 +261,7 @@ struct sdma_channel {
> unsigned int pc_from_device, pc_to_device;
> unsigned long flags;
> dma_addr_t per_address;
> + unsigned int pc_to_pc;
> unsigned long event_mask[2];
> unsigned long watermark_level;
> u32 shp_addr, per_addr;
> @@ -694,6 +696,7 @@ static void sdma_get_pc(struct sdma_channel *sdmac,
>
> sdmac->pc_from_device = 0;
> sdmac->pc_to_device = 0;
> + sdmac->pc_to_pc = 0;
>
> switch (peripheral_type) {
> case IMX_DMATYPE_MEMORY:
> @@ -763,6 +766,7 @@ static void sdma_get_pc(struct sdma_channel *sdmac,
>
> sdmac->pc_from_device = per_2_emi;
> sdmac->pc_to_device = emi_2_per;
> + sdmac->pc_to_pc = emi_2_emi;
> }
>
> static int sdma_load_context(struct sdma_channel *sdmac)
> @@ -775,11 +779,12 @@ static int sdma_load_context(struct sdma_channel *sdmac)
> int ret;
> unsigned long flags;
>
> - if (sdmac->direction == DMA_DEV_TO_MEM) {
> + if (sdmac->direction == DMA_DEV_TO_MEM)
> load_address = sdmac->pc_from_device;
> - } else {
> + else if (sdmac->direction == DMA_MEM_TO_MEM)
> + load_address = sdmac->pc_to_pc;
> + else
> load_address = sdmac->pc_to_device;
> - }
>
> if (load_address < 0)
> return load_address;
> @@ -1010,16 +1015,118 @@ static void sdma_free_chan_resources(struct dma_chan *chan)
> clk_disable(sdma->clk_ahb);
> }
>
> -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,
> - unsigned long flags, void *context)
> +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, ret;
> + struct sdma_buffer_descriptor *bd;
> +
> + if (!chan || !len || sdmac->status == DMA_IN_PROGRESS)
> + return NULL;
> +
> + if (len >= NUM_BD * SDMA_BD_MAX_CNT) {
> + dev_err(sdma->dev, "channel%d: maximum bytes exceeded:%d > %d\n"
> + , channel, len, NUM_BD * SDMA_BD_MAX_CNT);
> + goto err_out;
> + }
> +
> + sdmac->status = DMA_IN_PROGRESS;
> +
> + sdmac->buf_tail = 0;
> +
> + dev_dbg(sdma->dev, "memcpy: %x->%x, len=%d, channel=%d.\n",

%pad for dma_addr_t variables.

> + dma_src, dma_dst, len, channel);
> +
> + sdmac->direction = DMA_MEM_TO_MEM;
> +
> + ret = sdma_load_context(sdmac);
> + if (ret)
> + goto err_out;
> +
> + sdmac->chn_count = 0;
> +
> + do {
> + count = min_t(size_t, len, SDMA_BD_MAX_CNT);
> + bd = &sdmac->bd[i];
> + bd->buffer_addr = dma_src;
> + bd->ext_buffer_addr = dma_dst;
> + bd->mode.count = count;
> +
> + if (sdmac->word_size > DMA_SLAVE_BUSWIDTH_4_BYTES) {
> + ret = -EINVAL;
> + goto err_out;
> + }
> +
> + switch (sdmac->word_size) {
> + case DMA_SLAVE_BUSWIDTH_4_BYTES:
> + bd->mode.command = 0;
> + if (count & 3 || dma_dst & 3 || dma_src & 3)

Could it be like
if ((count | dma_dst | dma_src) & 3)
?

> + return NULL;
> + break;
> + case DMA_SLAVE_BUSWIDTH_2_BYTES:
> + bd->mode.command = 2;
> + if (count & 1 || dma_dst & 1 || dma_src & 1)

Similar here.

> + return NULL;
> + break;
> + case DMA_SLAVE_BUSWIDTH_1_BYTE:
> + bd->mode.command = 1;
> + break;
> + default:
> + return NULL;
> + }

Moreover, could you consider to make above piece of code (switch) a
separate function and re-use it in sdma_prep_slave_sg()?

> +
> + 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: %d dma: 0x%08x %s%s\n",
> + i, count, bd->buffer_addr,


> + param & BD_WRAP ? "wrap" : "",
> + param & BD_INTR ? " intr" : "");
> +
> + bd->mode.status = param;
> + sdmac->chn_count += count;
> + } while (len);
> +
> + sdmac->num_bd = i;
> + sdma->channel_control[channel].current_bd_ptr = sdmac->bd_phys;
> +
> + return &sdmac->desc;
> +err_out:
> + sdmac->status = DMA_ERROR;
> + return NULL;
> +}
> +
> +/*
> + * Please ensure dst_nents no smaller than src_nents , also every sg_len of
> + * dst_sg node no smaller than src_sg. To simply things, please use the same
> + * size of dst_sg as src_sg.
> + */
> +static struct dma_async_tx_descriptor *sdma_prep_sg(
> + struct dma_chan *chan,
> + struct scatterlist *dst_sg, unsigned int dst_nents,
> + struct scatterlist *src_sg, unsigned int src_nents,
> + enum dma_transfer_direction direction)
> {
> struct sdma_channel *sdmac = to_sdma_chan(chan);
> struct sdma_engine *sdma = sdmac->sdma;
> int ret, i, count;
> int channel = sdmac->channel;
> - struct scatterlist *sg;
> + struct scatterlist *sg_src = src_sg, *sg_dst = dst_sg;
>
> if (sdmac->status == DMA_IN_PROGRESS)
> return NULL;
> @@ -1030,32 +1137,38 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
> sdmac->buf_tail = 0;
>
> dev_dbg(sdma->dev, "setting up %d entries for channel %d.\n",
> - sg_len, channel);
> + src_nents, channel);
>
> sdmac->direction = direction;
> +
> ret = sdma_load_context(sdmac);
> if (ret)
> goto err_out;
>
> - if (sg_len > NUM_BD) {
> + if (src_nents > NUM_BD) {
> dev_err(sdma->dev, "SDMA channel %d: maximum number of sg exceeded: %d > %d\n",
> - channel, sg_len, NUM_BD);

%u for sg_len.
I guess the same for NUM_BD.

> + channel, src_nents, NUM_BD);
> ret = -EINVAL;
> goto err_out;
> }
>
> sdmac->chn_count = 0;
> - for_each_sg(sgl, sg, sg_len, i) {
> + for_each_sg(src_sg, sg_src, src_nents, i) {
> struct sdma_buffer_descriptor *bd = &sdmac->bd[i];
> int param;
>
> - bd->buffer_addr = sg->dma_address;
> + bd->buffer_addr = sg_src->dma_address;
>
> - count = sg_dma_len(sg);
> + if (direction == DMA_MEM_TO_MEM) {
> + BUG_ON(!sg_dst);
> + bd->ext_buffer_addr = sg_dst->dma_address;
> + }
> +
> + count = sg_dma_len(sg_src);
>
> - if (count > 0xffff) {
> + if (count > SDMA_BD_MAX_CNT) {
> dev_err(sdma->dev, "SDMA channel %d: maximum bytes for sg entry exceeded: %d > %d\n",
> - channel, count, 0xffff);
> + channel, count, SDMA_BD_MAX_CNT);
> ret = -EINVAL;
> goto err_out;
> }
> @@ -1071,12 +1184,14 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
> switch (sdmac->word_size) {
> case DMA_SLAVE_BUSWIDTH_4_BYTES:
> bd->mode.command = 0;
> - if (count & 3 || sg->dma_address & 3)
> + if (count & 3 || sg_src->dma_address & 3 ||
> + (sg_dst && (sg_dst->dma_address & 3)))
> return NULL;
> break;
> case DMA_SLAVE_BUSWIDTH_2_BYTES:
> bd->mode.command = 2;
> - if (count & 1 || sg->dma_address & 1)
> + if (count & 1 || sg_src->dma_address & 1 ||
> + (sg_dst && (sg_dst->dma_address & 1)))
> return NULL;
> break;
> case DMA_SLAVE_BUSWIDTH_1_BYTE:
> @@ -1088,21 +1203,23 @@ static struct dma_async_tx_descriptor *sdma_prep_slave_sg(
>
> param = BD_DONE | BD_EXTD | BD_CONT;
>
> - if (i + 1 == sg_len) {
> + if (i + 1 == src_nents) {
> param |= BD_INTR;
> param |= BD_LAST;
> param &= ~BD_CONT;
> }
>
> - dev_dbg(sdma->dev, "entry %d: count: %d dma: %#llx %s%s\n",
> - i, count, (u64)sg->dma_address,
> + dev_dbg(sdma->dev, "entry %d: count: %d dma: 0x%08x %s%s\n",
> + i, count, sg_src->dma_address,

%pad for dma_addr_t.

> param & BD_WRAP ? "wrap" : "",
> param & BD_INTR ? " intr" : "");
>
> bd->mode.status = param;
> + if (direction == DMA_MEM_TO_MEM)
> + sg_dst = sg_next(sg_dst);
> }
>
> - sdmac->num_bd = sg_len;
> + sdmac->num_bd = src_nents;
> sdma->channel_control[channel].current_bd_ptr = sdmac->bd_phys;
>
> return &sdmac->desc;
> @@ -1111,6 +1228,24 @@ err_out:
> return NULL;
> }
>
> +static struct dma_async_tx_descriptor *sdma_prep_memcpy_sg(
> + struct dma_chan *chan,
> + struct scatterlist *dst_sg, unsigned int dst_nents,
> + struct scatterlist *src_sg, unsigned int src_nents,
> + unsigned long flags)
> +{
> + return sdma_prep_sg(chan, dst_sg, dst_nents, src_sg, src_nents,
> + DMA_MEM_TO_MEM);
> +}
> +
> +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,
> + unsigned long flags, void *context)
> +{
> + return sdma_prep_sg(chan, NULL, 0, sgl, sg_len, direction);
> +}
> +
> static struct dma_async_tx_descriptor *sdma_prep_dma_cyclic(
> struct dma_chan *chan, dma_addr_t dma_addr, size_t buf_len,
> size_t period_len, enum dma_transfer_direction direction,
> @@ -1143,9 +1278,9 @@ static struct dma_async_tx_descriptor *sdma_prep_dma_cyclic(
> goto err_out;
> }
>
> - if (period_len > 0xffff) {
> + if (period_len > SDMA_BD_MAX_CNT) {
> dev_err(sdma->dev, "SDMA channel %d: maximum period size exceeded: %d > %d\n",
> - channel, period_len, 0xffff);
> + channel, period_len, SDMA_BD_MAX_CNT);

%zu for period_len. Check carefully print specifiers over your code,
please.

> goto err_out;
> }
>
> @@ -1206,6 +1341,8 @@ static int sdma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
> sdmac->watermark_level = dmaengine_cfg->src_maxburst *
> dmaengine_cfg->src_addr_width;
> sdmac->word_size = dmaengine_cfg->src_addr_width;
> + } else if (dmaengine_cfg->direction == DMA_MEM_TO_MEM) {
> + sdmac->word_size = dmaengine_cfg->dst_addr_width;
> } else {
> sdmac->per_address = dmaengine_cfg->dst_addr;
> sdmac->watermark_level = dmaengine_cfg->dst_maxburst *
> @@ -1516,6 +1653,7 @@ static int __init 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 */
> @@ -1578,6 +1716,8 @@ static int __init sdma_probe(struct platform_device *pdev)
> sdma->dma_device.device_tx_status = sdma_tx_status;
> sdma->dma_device.device_prep_slave_sg = sdma_prep_slave_sg;
> sdma->dma_device.device_prep_dma_cyclic = sdma_prep_dma_cyclic;
> + sdma->dma_device.device_prep_dma_memcpy = sdma_prep_memcpy;
> + sdma->dma_device.device_prep_dma_sg = sdma_prep_memcpy_sg;
> sdma->dma_device.device_control = sdma_control;
> sdma->dma_device.device_issue_pending = sdma_issue_pending;
> sdma->dma_device.dev->dma_parms = &sdma->dma_parms;


--
Andy Shevchenko <andriy.shevchenko@xxxxxxxxx>
Intel Finland Oy
---------------------------------------------------------------------
Intel Finland Oy
Registered Address: PL 281, 00181 Helsinki
Business Identity Code: 0357606 - 4
Domiciled in Helsinki

This e-mail and any attachments may contain confidential material for
the sole use of the intended recipient(s). Any review or distribution
by others is strictly prohibited. If you are not the intended
recipient, please contact the sender and delete all copies.
N‹§²æ¸›yú²X¬¶ÇvØ–)Þ{.nlj·¥Š{±‘êX§¶›¡Ü}©ž²ÆzÚj:+v‰¨¾«‘êZ+€Êzf£¢·hšˆ§~†­†Ûÿû®w¥¢¸?™¨è&¢)ßf”ùy§m…á«a¶Úÿ 0¶ìå