Add support for device_tx_status() callback as it is needed for
RZ/G2L SCIFA driver.
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>
---
v2->v3:
* No change.
v1->v2:
* Replaced the loop for->for_each_sg and dropped sgl and sg_len variables
from calculate_total_bytes_in_vd().
* Updated commit description.
---
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 81e72529f7d3..aaaae1c090ad 100644
--- a/drivers/dma/sh/rz-dmac.c
+++ b/drivers/dma/sh/rz-dmac.c
@@ -108,10 +108,12 @@ 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
@@ -650,6 +652,171 @@ 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)
+{
+ unsigned int i, size = 0;
+ struct scatterlist *sg;
+
+ for_each_sg(desc->sg, sg, desc->sgcount, i)
+ size += sg_dma_len(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
@@ -932,7 +1099,7 @@ 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
