[PATCH v2 10/11] dma: mmp_pdma: add support for residue reporting
Vinod Koul
vinod.koul at intel.com
Wed Aug 14 04:19:37 EDT 2013
On Sat, Aug 10, 2013 at 06:52:24PM +0200, Daniel Mack wrote:
> In order to report the channel's residue, we have to memorize the first
> dma buffer position when the channel is configured.
>
> Signed-off-by: Daniel Mack <zonque at gmail.com>
> ---
> drivers/dma/mmp_pdma.c | 39 +++++++++++++++++++++++++++++++++++++--
> 1 file changed, 37 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/dma/mmp_pdma.c b/drivers/dma/mmp_pdma.c
> index 7a0956b..ab0303b 100644
> --- a/drivers/dma/mmp_pdma.c
> +++ b/drivers/dma/mmp_pdma.c
> @@ -28,8 +28,8 @@
> #define DALGN 0x00a0
> #define DINT 0x00f0
> #define DDADR 0x0200
> -#define DSADR 0x0204
> -#define DTADR 0x0208
> +#define DSADR(n) (0x0204 + ((n) << 4))
> +#define DTADR(n) (0x0208 + ((n) << 4))
> #define DCMD 0x020c
>
> #define DCSR_RUN (1 << 31) /* Run Bit (read / write) */
> @@ -97,6 +97,13 @@ struct mmp_pdma_chan {
> struct dma_async_tx_descriptor desc;
> struct mmp_pdma_phy *phy;
> enum dma_transfer_direction dir;
> + /*
> + * We memorize the original start address of the first descriptor as
> + * well as the original total length so we can later determine the
> + * channel's residue.
> + */
> + dma_addr_t start_addr;
> + u32 total_len;
well instead of rembering two values and doing two computations runtime, you can store
last_addr = start_addr + total_len;
then calculate
residue = last_addr - dma_poistion;
Neverthless, this is okay too, so am going to apply this one..
~Vinod
>
> /* channel's basic info */
> struct tasklet_struct tasklet;
> @@ -470,6 +477,13 @@ mmp_pdma_prep_memcpy(struct dma_chan *dchan,
> chan->dcmd |= DCMD_BURST32;
> }
>
> + if (chan->dir == DMA_MEM_TO_DEV)
> + chan->start_addr = dma_src;
> + else
> + chan->start_addr = dma_dst;
> +
> + chan->total_len = len;
> +
> do {
> /* Allocate the link descriptor from DMA pool */
> new = mmp_pdma_alloc_descriptor(chan);
> @@ -541,11 +555,17 @@ mmp_pdma_prep_slave_sg(struct dma_chan *dchan, struct scatterlist *sgl,
> return NULL;
>
> chan->byte_align = false;
> + chan->total_len = 0;
>
> for_each_sg(sgl, sg, sg_len, i) {
> addr = sg_dma_address(sg);
> avail = sg_dma_len(sgl);
>
> + if (!first)
> + chan->start_addr = addr;
> +
> + chan->total_len += avail;
> +
> do {
> len = min_t(size_t, avail, PDMA_MAX_DESC_BYTES);
> if (addr & 0x7)
> @@ -672,6 +692,20 @@ static int mmp_pdma_control(struct dma_chan *dchan, enum dma_ctrl_cmd cmd,
> return ret;
> }
>
> +static unsigned int mmp_pdma_residue(struct mmp_pdma_chan *chan)
> +{
> + u32 curr, done;
> +
> + if (chan->dir == DMA_DEV_TO_MEM)
> + curr = readl(chan->phy->base + DTADR(chan->phy->idx));
> + else
> + curr = readl(chan->phy->base + DSADR(chan->phy->idx));
> +
> + done = curr - chan->start_addr;
> +
> + return chan->total_len - done;
simpler logic:
store the
> +}
> +
> static enum dma_status mmp_pdma_tx_status(struct dma_chan *dchan,
> dma_cookie_t cookie, struct dma_tx_state *txstate)
> {
> @@ -681,6 +715,7 @@ static enum dma_status mmp_pdma_tx_status(struct dma_chan *dchan,
>
> spin_lock_irqsave(&chan->desc_lock, flags);
> ret = dma_cookie_status(dchan, cookie, txstate);
> + txstate->residue = mmp_pdma_residue(chan);
> spin_unlock_irqrestore(&chan->desc_lock, flags);
>
> return ret;
> --
> 1.8.3.1
>
--
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