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Date: Wed, 21 May 2014 16:26:52 +0530
From: Vinod Koul <vinod.koul@...el.com>
To: Robin Gong <b38343@...escale.com>
Cc: dan.j.williams@...el.com, dmaengine@...r.kernel.org,
linux-kernel@...r.kernel.org, andriy.shevchenko@...ux.jf.intel.com
Subject: Re: [PATCH v3] dma: imx-sdma: add support for sdma memory copy
On Tue, May 06, 2014 at 10:12:48AM +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@...escale.com>
>
> ---
> change:
> --v3:
> 1. remove redundant check for bus width
>
> --v2:
> 1. correct some printk format, such as %pad for dma_addr_t
> 2. split duplicated code in prep_dma_memcpy and prep_dma_sg to make code clean.
>
> Signed-off-by: Robin Gong <b38343@...escale.com>
> ---
> drivers/dma/imx-sdma.c | 250 ++++++++++++++++++++++++++++++++++++-----------
> 1 files changed, 191 insertions(+), 59 deletions(-)
>
> diff --git a/drivers/dma/imx-sdma.c b/drivers/dma/imx-sdma.c
> index 4e79183..9abc164 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
else is not proper here as enum defines one more field. So else-if would be apt.
> load_address = sdmac->pc_to_device;
> - }
>
> if (load_address < 0)
> return load_address;
> @@ -1010,99 +1015,203 @@ 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 int sdma_transfer_init(struct sdma_channel *sdmac,
> + enum dma_transfer_direction direction)
> +{
> + int ret = 0;
> +
> + sdmac->status = DMA_IN_PROGRESS;
> + sdmac->buf_tail = 0;
> + sdmac->flags = 0;
> + sdmac->direction = direction;
> +
> + ret = sdma_load_context(sdmac);
> + if (ret)
> + return ret;
> +
> + sdmac->chn_count = 0;
> +
> + return ret;
> +}
> +
> +static int check_bd_buswidth(struct sdma_buffer_descriptor *bd,
> + struct sdma_channel *sdmac, int count,
> + dma_addr_t dma_dst, dma_addr_t dma_src)
> +{
> + int ret = 0;
> +
> + switch (sdmac->word_size) {
> + case DMA_SLAVE_BUSWIDTH_4_BYTES:
> + bd->mode.command = 0;
> + if ((count | dma_dst | dma_src) & 3)
> + ret = -EINVAL;
> + break;
> + case DMA_SLAVE_BUSWIDTH_2_BYTES:
> + bd->mode.command = 2;
> + if ((count | dma_dst | dma_src) & 1)
> + ret = -EINVAL;
> + break;
> + case DMA_SLAVE_BUSWIDTH_1_BYTE:
> + bd->mode.command = 1;
> + break;
> + default:
> + return -EINVAL;
> + }
> +
> + return ret;
> +}
This looks like a code reorg change, perhpas another patch?
> +
> +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 ret, i, count;
> int channel = sdmac->channel;
> - struct scatterlist *sg;
> + size_t count;
> + int i = 0, param;
> + struct sdma_buffer_descriptor *bd;
>
> - if (sdmac->status == DMA_IN_PROGRESS)
> + if (!chan || !len || sdmac->status == DMA_IN_PROGRESS)
> return NULL;
> - sdmac->status = DMA_IN_PROGRESS;
>
> - sdmac->flags = 0;
> -
> - sdmac->buf_tail = 0;
> + if (len >= NUM_BD * SDMA_BD_MAX_CNT) {
> + dev_err(sdma->dev, "channel%d: maximum bytes exceeded:%zu > %d\n"
> + , channel, len, NUM_BD * SDMA_BD_MAX_CNT);
> + goto err_out;
> + }
>
> - dev_dbg(sdma->dev, "setting up %d entries for channel %d.\n",
> - sg_len, channel);
> + dev_dbg(sdma->dev, "memcpy: %pad->%pad, len=%zu, channel=%d.\n",
> + &dma_src, &dma_dst, len, channel);
>
> - sdmac->direction = direction;
> - ret = sdma_load_context(sdmac);
> - if (ret)
> + if (sdma_transfer_init(sdmac, DMA_MEM_TO_MEM))
> goto err_out;
>
> - if (sg_len > NUM_BD) {
> + 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 (check_bd_buswidth(bd, sdmac, count, dma_dst, dma_src))
> + goto err_out;
> +
> + 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%u %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_src = src_sg, *sg_dst = dst_sg;
> +
> + if (sdmac->status == DMA_IN_PROGRESS)
> + return NULL;
> +
> + dev_dbg(sdma->dev, "setting up %d entries for channel %d.\n",
> + src_nents, channel);
> +
> + 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);
> - ret = -EINVAL;
> + channel, src_nents, NUM_BD);
> goto err_out;
> }
>
> - sdmac->chn_count = 0;
> - for_each_sg(sgl, sg, sg_len, i) {
> + if (sdma_transfer_init(sdmac, direction))
> + goto err_out;
> +
> + 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);
why should this be direction specfic?
> + 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);
> - ret = -EINVAL;
> + channel, count, SDMA_BD_MAX_CNT);
> goto err_out;
> }
>
> bd->mode.count = count;
> sdmac->chn_count += count;
>
> - if (sdmac->word_size > DMA_SLAVE_BUSWIDTH_4_BYTES) {
> - ret = -EINVAL;
> - goto err_out;
> - }
> + if (direction == DMA_MEM_TO_MEM)
> + ret = check_bd_buswidth(bd, sdmac, count,
> + sg_dst->dma_address,
> + sg_src->dma_address);
> + else
> + ret = check_bd_buswidth(bd, sdmac, count, 0,
> + sg_src->dma_address);
>
> - switch (sdmac->word_size) {
> - case DMA_SLAVE_BUSWIDTH_4_BYTES:
> - bd->mode.command = 0;
> - if (count & 3 || sg->dma_address & 3)
> - return NULL;
> - break;
> - case DMA_SLAVE_BUSWIDTH_2_BYTES:
> - bd->mode.command = 2;
> - if (count & 1 || sg->dma_address & 1)
> - return NULL;
> - break;
> - case DMA_SLAVE_BUSWIDTH_1_BYTE:
> - bd->mode.command = 1;
> - break;
> - default:
> - return NULL;
> - }
> + if (ret)
> + goto err_out;
>
> 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: %pad %s%s\n",
> + i, count, &sg_src->dma_address,
> 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 +1220,24 @@ 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 +1270,9 @@ static struct dma_async_tx_descriptor *sdma_prep_dma_cyclic(
> goto err_out;
> }
>
> - if (period_len > 0xffff) {
> - dev_err(sdma->dev, "SDMA channel %d: maximum period size exceeded: %d > %d\n",
> - channel, period_len, 0xffff);
> + if (period_len > SDMA_BD_MAX_CNT) {
> + dev_err(sdma->dev, "SDMA channel %d: maximum period size exceeded: %zu > %d\n",
> + channel, period_len, SDMA_BD_MAX_CNT);
this macro change should have been another patch too...
--
~Vinod
--
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