dma: pl330: add infinite loop functionality

This patch adds an infinite loop feature to PL330 driver.
This feature removes the stop period of PL330 HW.

Change-Id: I5cb5be0eca76497c80ba0ad44021e62776c843d9
Signed-off-by: Seokju Yoon <sukju.yoon@samsung.com>

diff --git a/drivers/dma/pl330.c b/drivers/dma/pl330.c
index 86c3a449b2b18424c67544c007b9acfd25a6756a..1560957cf8fcdb7748cbf2bcfc75c716f3cbb099 100644 (file)
--- a/drivers/dma/pl330.c
+++ b/drivers/dma/pl330.c
@@ -534,6 +534,7 @@ struct dma_pl330_desc {
        unsigned peri:5;
        /* Hook to attach to DMAC's list of reqs with due callback */
        struct list_head rqd;
+       unsigned int infiniteloop;
 };
 
 struct _xfer_spec {
@@ -1167,6 +1168,77 @@ static int _bursts(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
        return off;
 }
 
+/* Returns bytes consumed */
+static inline int _loop_infiniteloop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
+               unsigned long bursts, const struct _xfer_spec *pxs, int ev)
+{
+       int cyc, off;
+       unsigned lcnt0, lcnt1, ljmp0, ljmp1, ljmpfe;
+       struct _arg_LPEND lpend;
+
+       off = 0;
+       ljmpfe = off;
+       lcnt0 = pxs->desc->infiniteloop;
+
+       if (bursts > 256) {
+               lcnt1 = 256;
+               cyc = bursts / 256;
+       } else {
+               lcnt1 = bursts;
+               cyc = 1;
+       }
+
+       /* forever loop */
+       off += _emit_MOV(dry_run, &buf[off], SAR, pxs->desc->px.src_addr);
+       off += _emit_MOV(dry_run, &buf[off], DAR, pxs->desc->px.dst_addr);
+       if (pxs->desc->rqtype != DMA_MEM_TO_MEM)
+               off += _emit_FLUSHP(dry_run, &buf[off], pxs->desc->peri);
+
+       /* loop0 */
+       off += _emit_LP(dry_run, &buf[off], 0,  lcnt0);
+       ljmp0 = off;
+
+       /* loop1 */
+       off += _emit_LP(dry_run, &buf[off], 1, lcnt1);
+       ljmp1 = off;
+       off += _bursts(pl330, dry_run, &buf[off], pxs, cyc);
+       lpend.cond = ALWAYS;
+       lpend.forever = false;
+       lpend.loop = 1;
+       lpend.bjump = off - ljmp1;
+       off += _emit_LPEND(dry_run, &buf[off], &lpend);
+
+       /* remainder */
+       lcnt1 = bursts - (lcnt1 * cyc);
+
+       if (lcnt1) {
+               off += _emit_LP(dry_run, &buf[off], 1, lcnt1);
+               ljmp1 = off;
+               off += _bursts(pl330, dry_run, &buf[off], pxs, 1);
+               lpend.cond = ALWAYS;
+               lpend.forever = false;
+               lpend.loop = 1;
+               lpend.bjump = off - ljmp1;
+               off += _emit_LPEND(dry_run, &buf[off], &lpend);
+       }
+
+       off += _emit_SEV(dry_run, &buf[off], ev);
+
+       lpend.cond = ALWAYS;
+       lpend.forever = false;
+       lpend.loop = 0;
+       lpend.bjump = off - ljmp0;
+       off += _emit_LPEND(dry_run, &buf[off], &lpend);
+
+       lpend.cond = ALWAYS;
+       lpend.forever = true;
+       lpend.loop = 1;
+       lpend.bjump = off - ljmpfe;
+       off +=  _emit_LPEND(dry_run, &buf[off], &lpend);
+
+       return off;
+}
+
 /* Returns bytes consumed and updates bursts */
 static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
                unsigned long *bursts, const struct _xfer_spec *pxs)
@@ -1249,6 +1321,22 @@ static inline int _loop(struct pl330_dmac *pl330, unsigned dry_run, u8 buf[],
        return off;
 }
 
+static inline int _setup_xfer_infiniteloop(struct pl330_dmac *pl330,
+               unsigned dry_run, u8 buf[],
+               const struct _xfer_spec *pxs, int ev)
+{
+       struct pl330_xfer *x = &pxs->desc->px;
+       u32 ccr = pxs->ccr;
+       unsigned long bursts = BYTE_TO_BURST(x->bytes, ccr);
+       int off = 0;
+
+       /* Setup Loop(s) */
+       off += _loop_infiniteloop(pl330, dry_run, &buf[off], bursts, pxs, ev);
+
+       return off;
+}
+
+
 static inline int _setup_loops(struct pl330_dmac *pl330,
                               unsigned dry_run, u8 buf[],
                               const struct _xfer_spec *pxs)
@@ -1308,12 +1396,18 @@ static int _setup_req(struct pl330_dmac *pl330, unsigned dry_run,
        if (x->bytes % (BRST_SIZE(pxs->ccr) * BRST_LEN(pxs->ccr)))
                return -EINVAL;
 
-       off += _setup_xfer(pl330, dry_run, &buf[off], pxs);
+       if (!pxs->desc->infiniteloop) {
+               off += _setup_xfer(pl330, dry_run, &buf[off], pxs);
 
-       /* DMASEV peripheral/event */
-       off += _emit_SEV(dry_run, &buf[off], thrd->ev);
-       /* DMAEND */
-       off += _emit_END(dry_run, &buf[off]);
+               /* DMASEV peripheral/event */
+               off += _emit_SEV(dry_run, &buf[off], thrd->ev);
+               /* DMAEND */
+               off += _emit_END(dry_run, &buf[off]);
+       } else {
+               off += _setup_xfer_infiniteloop(pl330,
+                               dry_run, &buf[off],
+                               pxs, thrd->ev);
+       }
 
        return off;
 }
@@ -1426,6 +1520,8 @@ xfer_exit:
        return ret;
 }
 
+static void pl330_tasklet(unsigned long data);
+
 static void dma_pl330_rqcb(struct dma_pl330_desc *desc, enum pl330_op_err err)
 {
        struct dma_pl330_chan *pch;
@@ -1446,7 +1542,10 @@ static void dma_pl330_rqcb(struct dma_pl330_desc *desc, enum pl330_op_err err)
 
        spin_unlock_irqrestore(&pch->lock, flags);
 
-       tasklet_schedule(&pch->task);
+       if (desc->infiniteloop)
+               pl330_tasklet((unsigned long)pch);
+       else
+               tasklet_schedule(&pch->task);
 }
 
 static void pl330_dotask(unsigned long data)
@@ -1575,12 +1674,15 @@ static int pl330_update(struct pl330_dmac *pl330)
 
                        /* Detach the req */
                        descdone = thrd->req[active].desc;
-                       thrd->req[active].desc = NULL;
 
                        thrd->req_running = -1;
 
-                       /* Get going again ASAP */
-                       _start(thrd);
+                       if (!descdone->infiniteloop) {
+                               thrd->req[active].desc = NULL;
+
+                               /* Get going again ASAP */
+                               _start(thrd);
+                       }
 
                        /* For now, just make a list of callbacks to be done */
                        list_add_tail(&descdone->rqd, &pl330->req_done);
@@ -2471,6 +2573,7 @@ static struct dma_pl330_desc *pl330_get_desc(struct dma_pl330_chan *pch)
        desc->txd.cookie = 0;
        async_tx_ack(&desc->txd);
 
+       desc->infiniteloop = 0;
        desc->peri = peri_id ? pch->chan.chan_id : 0;
        desc->rqcfg.pcfg = &pch->dmac->pcfg;
 
@@ -2549,6 +2652,7 @@ static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
        unsigned int i;
        dma_addr_t dst;
        dma_addr_t src;
+       unsigned int *infinite = context;
 
        if (len % period_len != 0)
                return NULL;
@@ -2607,6 +2711,7 @@ static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
                desc->rqcfg.brst_size = pch->burst_sz;
                desc->rqcfg.brst_len = 1;
                desc->bytes_requested = period_len;
+               desc->infiniteloop = *infinite;
                fill_px(&desc->px, dst, src, period_len);
 
                if (!first)