On 24-03-23, 09:49, Biju Das wrote:
> The device_tx_status() callback is needed for serial DMA (RZ/G2L
> SCIFA). Add support for device_tx_status() callback.
>
> Based on a patch in the BSP by Long Luu similar to rcar-dmac
> <long.luu.ur@xxxxxxxxxxx>
>
> Signed-off-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> ---
> drivers/dma/sh/rz-dmac.c | 169 ++++++++++++++++++++++++++++++++++++++-
> 1 file changed, 168 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/dma/sh/rz-dmac.c b/drivers/dma/sh/rz-dmac.c
> index a04a37ce03fd..3625925d9f9f 100644
> --- a/drivers/dma/sh/rz-dmac.c
> +++ b/drivers/dma/sh/rz-dmac.c
> @@ -110,10 +110,12 @@ struct rz_dmac {
> * Registers
> */
>
> +#define CRTB 0x0020
> #define CHSTAT 0x0024
> #define CHCTRL 0x0028
> #define CHCFG 0x002c
> #define NXLA 0x0038
> +#define CRLA 0x003c
>
> #define DCTRL 0x0000
>
> @@ -655,6 +657,171 @@ static void rz_dmac_device_synchronize(struct dma_chan *chan)
> rz_dmac_set_dmars_register(dmac, channel->index, 0);
> }
>
> +static unsigned int calculate_total_bytes_in_vd(struct rz_dmac_desc *desc)
> +{
> + struct scatterlist *sg, *sgl = desc->sg;
> + unsigned int i, size, sg_len = desc->sgcount;
> +
> + for (i = 0, size = 0, sg = sgl; i < sg_len; i++, sg = sg_next(sg))
> + size += sg_dma_len(sg);
for_each_sg() ?
> +
> + return size;
> +}
> +
> +static unsigned int calculate_residue_bytes_in_vd(struct rz_dmac_chan *channel)
> +{
> + struct rz_lmdesc *lmdesc = channel->lmdesc.head;
> + struct dma_chan *chan = &channel->vc.chan;
> + struct rz_dmac *dmac = to_rz_dmac(chan->device);
> + unsigned int residue = 0, i = 0;
> + unsigned int crla;
> +
> + /* get current lmdesc */
> + crla = rz_dmac_ch_readl(channel, CRLA, 1);
> + while (!(lmdesc->nxla == crla)) {
> + lmdesc++;
> + if (lmdesc >= (channel->lmdesc.base + DMAC_NR_LMDESC))
> + lmdesc = channel->lmdesc.base;
> + i++;
> + /* Not found current lmdesc */
> + if (i > DMAC_NR_LMDESC)
> + return 0;
> + }
> +
> + /* Point to current processing lmdesc in hardware */
> + lmdesc++;
> + if (lmdesc >= (channel->lmdesc.base + DMAC_NR_LMDESC))
> + lmdesc = channel->lmdesc.base;
> +
> + /* Calculate residue from next lmdesc to end of virtual desc*/
> + while (lmdesc->chcfg & CHCFG_DEM) {
> + lmdesc++;
> + if (lmdesc >= (channel->lmdesc.base + DMAC_NR_LMDESC))
> + lmdesc = channel->lmdesc.base;
> + residue += lmdesc->tb;
> + }
> +
> + dev_dbg(dmac->dev, "%s: Getting residue is %d\n", __func__, residue);
> +
> + return residue;
> +}
> +
> +static unsigned int rz_dmac_chan_get_residue(struct rz_dmac_chan *channel,
> + dma_cookie_t cookie)
> +{
> + struct rz_dmac_desc *current_desc, *desc;
> + enum dma_status status;
> + unsigned int residue;
> + unsigned int crla;
> + unsigned int crtb;
> + unsigned int i;
> +
> + /* Get current processing virtual descriptor */
> + current_desc = list_first_entry(&channel->ld_active,
> + struct rz_dmac_desc, node);
> + if (!current_desc)
> + return 0;
> +
> + /*
> + * If the cookie corresponds to a descriptor that has been completed
> + * there is no residue. The same check has already been performed by the
> + * caller but without holding the channel lock, so the descriptor could
> + * now be complete.
> + */
> + status = dma_cookie_status(&channel->vc.chan, cookie, NULL);
> + if (status == DMA_COMPLETE)
> + return 0;
> +
> + /*
> + * If the cookie doesn't correspond to the currently processing virtual
> + * descriptor then the descriptor hasn't been processed yet, and the
> + * residue is equal to the full descriptor size.
> + * Also, a client driver is possible to call this function before
> + * rz_dmac_irq_handler_thread() runs. In this case, the running
> + * descriptor will be the next descriptor, and the done list will
> + * appear. So, if the argument cookie matches the done list's cookie,
> + * we can assume the residue is zero.
> + */
> + if (cookie != current_desc->vd.tx.cookie) {
> + list_for_each_entry(desc, &channel->ld_free, node) {
> + if (cookie == desc->vd.tx.cookie)
> + return 0;
> + }
> +
> + list_for_each_entry(desc, &channel->ld_queue, node) {
> + if (cookie == desc->vd.tx.cookie)
> + return calculate_total_bytes_in_vd(desc);
> + }
> +
> + list_for_each_entry(desc, &channel->ld_active, node) {
> + if (cookie == desc->vd.tx.cookie)
> + return calculate_total_bytes_in_vd(desc);
> + }
> +
> + /*
> + * No descriptor found for the cookie, there's thus no residue.
> + * This shouldn't happen if the calling driver passes a correct
> + * cookie value.
> + */
> + WARN(1, "No descriptor for cookie!");
> + return 0;
> + }
> +
> + /*
> + * Correspond to the currently processing virtual descriptor
> + *
> + * Make sure the hardware does not move to next lmdesc
> + * while reading the counter.
> + * Trying it 3 times should be enough: Initial read, retry, retry
> + * for the paranoid.
> + * The current lmdesc running in hardware is channel.lmdesc.head
> + */
> + for (i = 0; i < 3; i++) {
> + crla = rz_dmac_ch_readl(channel, CRLA, 1);
> + crtb = rz_dmac_ch_readl(channel, CRTB, 1);
> + /* Still the same? */
> + if (crla == rz_dmac_ch_readl(channel, CRLA, 1))
> + break;
> + }
> +
> + WARN_ONCE(i >= 3, "residue might be not continuous!");
> +
> + /*
> + * Calculate number of byte transferred in processing virtual descriptor
> + * One virtual descriptor can have many lmdesc
> + */
> + residue = crtb;
> + residue += calculate_residue_bytes_in_vd(channel);
> +
> + return residue;
> +}
> +
> +static enum dma_status rz_dmac_tx_status(struct dma_chan *chan,
> + dma_cookie_t cookie,
> + struct dma_tx_state *txstate)
> +{
> + struct rz_dmac_chan *channel = to_rz_dmac_chan(chan);
> + enum dma_status status;
> + unsigned int residue;
> + unsigned long flags;
> +
> + status = dma_cookie_status(chan, cookie, txstate);
> + if (status == DMA_COMPLETE || !txstate)
> + return status;
> +
> + spin_lock_irqsave(&channel->vc.lock, flags);
> + residue = rz_dmac_chan_get_residue(channel, cookie);
> + spin_unlock_irqrestore(&channel->vc.lock, flags);
> +
> + /* if there's no residue, the cookie is complete */
> + if (!residue)
> + return DMA_COMPLETE;
> +
> + dma_set_residue(txstate, residue);
> +
> + return status;
> +}
> +
> /*
> * -----------------------------------------------------------------------------
> * IRQ handling
> @@ -937,7 +1104,7 @@ static int rz_dmac_probe(struct platform_device *pdev)
>
> engine->device_alloc_chan_resources = rz_dmac_alloc_chan_resources;
> engine->device_free_chan_resources = rz_dmac_free_chan_resources;
> - engine->device_tx_status = dma_cookie_status;
> + engine->device_tx_status = rz_dmac_tx_status;
> engine->device_prep_slave_sg = rz_dmac_prep_slave_sg;
> engine->device_prep_dma_memcpy = rz_dmac_prep_dma_memcpy;
> engine->device_config = rz_dmac_config;
> --
> 2.25.1
--
~Vinod
