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dmaengine: pl330: make transfer run infinitely without CPU intervention
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this patch is based on "https://patchwork.kernel.org/patch/8349321/"

Change-Id: I377d1590186ce6e17983b931ad035d58a9e69e85
Signed-off-by: Sugar Zhang <sugar.zhang@rock-chips.com>
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@rkhuangtao
Sugar Zhang authored and rkhuangtao committed Jun 1, 2017
1 parent f090065 commit e8a6e50
Showing 1 changed file with 94 additions and 105 deletions.
199 changes: 94 additions & 105 deletions drivers/dma/pl330.c
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Original file line number Diff line number Diff line change
Expand Up @@ -447,9 +447,6 @@ struct dma_pl330_chan {
int burst_len; /* the number of burst */
dma_addr_t fifo_addr;

/* for cyclic capability */
bool cyclic;

/* for runtime pm tracking */
bool active;
};
Expand Down Expand Up @@ -535,6 +532,10 @@ struct dma_pl330_desc {
unsigned peri:5;
/* Hook to attach to DMAC's list of reqs with due callback */
struct list_head rqd;

/* For cyclic capability */
bool cyclic;
size_t num_periods;
};

struct _xfer_spec {
Expand Down Expand Up @@ -1321,16 +1322,19 @@ static inline int _setup_loops(struct pl330_dmac *pl330,
}

static inline int _setup_xfer(struct pl330_dmac *pl330,
unsigned dry_run, u8 buf[],
unsigned dry_run, u8 buf[], u32 period,
const struct _xfer_spec *pxs)
{
struct pl330_xfer *x = &pxs->desc->px;
struct pl330_reqcfg *rqcfg = &pxs->desc->rqcfg;
int off = 0;

/* DMAMOV SAR, x->src_addr */
off += _emit_MOV(dry_run, &buf[off], SAR, x->src_addr);
off += _emit_MOV(dry_run, &buf[off], SAR,
x->src_addr + rqcfg->src_inc * period * x->bytes);
/* DMAMOV DAR, x->dst_addr */
off += _emit_MOV(dry_run, &buf[off], DAR, x->dst_addr);
off += _emit_MOV(dry_run, &buf[off], DAR,
x->dst_addr + rqcfg->dst_inc * period * x->bytes);

/* Setup Loop(s) */
off += _setup_loops(pl330, dry_run, &buf[off], pxs);
Expand Down Expand Up @@ -1364,11 +1368,14 @@ static int _setup_req(struct pl330_dmac *pl330, unsigned dry_run,
struct pl330_xfer *x;
u8 *buf = req->mc_cpu;
int off = 0;
int period;
int again_off;

PL330_DBGMC_START(req->mc_bus);

/* DMAMOV CCR, ccr */
off += _emit_MOV(dry_run, &buf[off], CCR, pxs->ccr);
again_off = off;

x = &pxs->desc->px;
if (pl330->peripherals_req_type != BURST) {
Expand All @@ -1377,12 +1384,27 @@ static int _setup_req(struct pl330_dmac *pl330, unsigned dry_run,
return -EINVAL;
}

off += _setup_xfer(pl330, dry_run, &buf[off], pxs);
for (period = 0; period < pxs->desc->num_periods; period++) {
off += _setup_xfer(pl330, dry_run, &buf[off], period, pxs);

/* DMASEV peripheral/event */
off += _emit_SEV(dry_run, &buf[off], thrd->ev);
}

/* DMASEV peripheral/event */
off += _emit_SEV(dry_run, &buf[off], thrd->ev);
/* DMAEND */
off += _emit_END(dry_run, &buf[off]);
if (!pxs->desc->cyclic) {
/* DMAEND */
off += _emit_END(dry_run, &buf[off]);
} else {
struct _arg_LPEND lpend;
/* LP */
off += _emit_LP(dry_run, &buf[off], 0, 255);
/* LPEND */
lpend.cond = ALWAYS;
lpend.forever = false;
lpend.loop = 0;
lpend.bjump = off - again_off;
off += _emit_LPEND(dry_run, &buf[off], &lpend);
}

return off;
}
Expand Down Expand Up @@ -1644,12 +1666,13 @@ 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->cyclic) {
thrd->req[active].desc = NULL;
thrd->req_running = -1;
/* 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);
Expand Down Expand Up @@ -2028,12 +2051,27 @@ static void pl330_tasklet(unsigned long data)
spin_lock_irqsave(&pch->lock, flags);

/* Pick up ripe tomatoes */
list_for_each_entry_safe(desc, _dt, &pch->work_list, node)
list_for_each_entry_safe(desc, _dt, &pch->work_list, node) {
if (desc->status == DONE) {
if (!pch->cyclic)
if (!desc->cyclic) {
dma_cookie_complete(&desc->txd);
list_move_tail(&desc->node, &pch->completed_list);
list_move_tail(&desc->node, &pch->completed_list);
} else {
dma_async_tx_callback callback;
void *callback_param;

desc->status = BUSY;
callback = desc->txd.callback;
callback_param = desc->txd.callback_param;

if (callback) {
spin_unlock_irqrestore(&pch->lock, flags);
callback(callback_param);
spin_lock_irqsave(&pch->lock, flags);
}
}
}
}

/* Try to submit a req imm. next to the last completed cookie */
fill_queue(pch);
Expand Down Expand Up @@ -2061,20 +2099,8 @@ static void pl330_tasklet(unsigned long data)
callback = desc->txd.callback;
callback_param = desc->txd.callback_param;

if (pch->cyclic) {
desc->status = PREP;
list_move_tail(&desc->node, &pch->work_list);
if (power_down) {
pch->active = true;
spin_lock(&pch->thread->dmac->lock);
_start(pch->thread);
spin_unlock(&pch->thread->dmac->lock);
power_down = false;
}
} else {
desc->status = FREE;
list_move_tail(&desc->node, &pch->dmac->desc_pool);
}
desc->status = FREE;
list_move_tail(&desc->node, &pch->dmac->desc_pool);

dma_descriptor_unmap(&desc->txd);

Expand Down Expand Up @@ -2134,7 +2160,6 @@ static int pl330_alloc_chan_resources(struct dma_chan *chan)
spin_lock_irqsave(&pch->lock, flags);

dma_cookie_init(chan);
pch->cyclic = false;

pch->thread = pl330_request_channel(pl330);
if (!pch->thread) {
Expand Down Expand Up @@ -2257,8 +2282,7 @@ static void pl330_free_chan_resources(struct dma_chan *chan)
pl330_release_channel(pch->thread);
pch->thread = NULL;

if (pch->cyclic)
list_splice_tail_init(&pch->work_list, &pch->dmac->desc_pool);
list_splice_tail_init(&pch->work_list, &pch->dmac->desc_pool);

spin_unlock_irqrestore(&pch->lock, flags);
pm_runtime_mark_last_busy(pch->dmac->ddma.dev);
Expand Down Expand Up @@ -2312,7 +2336,7 @@ pl330_tx_status(struct dma_chan *chan, dma_cookie_t cookie,

/* Check in pending list */
list_for_each_entry(desc, &pch->work_list, node) {
if (desc->status == DONE)
if (desc->status == DONE && !desc->cyclic)
transferred = desc->bytes_requested;
else if (running && desc == running)
transferred =
Expand Down Expand Up @@ -2384,12 +2408,8 @@ static dma_cookie_t pl330_tx_submit(struct dma_async_tx_descriptor *tx)
/* Assign cookies to all nodes */
while (!list_empty(&last->node)) {
desc = list_entry(last->node.next, struct dma_pl330_desc, node);
if (pch->cyclic) {
desc->txd.callback = last->txd.callback;
desc->txd.callback_param = last->txd.callback_param;
}
desc->last = false;

desc->last = false;
dma_cookie_assign(&desc->txd);

list_move_tail(&desc->node, &pch->submitted_list);
Expand Down Expand Up @@ -2489,6 +2509,9 @@ static struct dma_pl330_desc *pl330_get_desc(struct dma_pl330_chan *pch)
desc->peri = peri_id ? pch->chan.chan_id : 0;
desc->rqcfg.pcfg = &pch->dmac->pcfg;

desc->cyclic = false;
desc->num_periods = 1;

dma_async_tx_descriptor_init(&desc->txd, &pch->chan);

return desc;
Expand Down Expand Up @@ -2558,10 +2581,8 @@ static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
size_t period_len, enum dma_transfer_direction direction,
unsigned long flags)
{
struct dma_pl330_desc *desc = NULL, *first = NULL;
struct dma_pl330_desc *desc = NULL;
struct dma_pl330_chan *pch = to_pchan(chan);
struct pl330_dmac *pl330 = pch->dmac;
unsigned int i;
dma_addr_t dst;
dma_addr_t src;

Expand All @@ -2574,70 +2595,38 @@ static struct dma_async_tx_descriptor *pl330_prep_dma_cyclic(
return NULL;
}

for (i = 0; i < len / period_len; i++) {
desc = pl330_get_desc(pch);
if (!desc) {
dev_err(pch->dmac->ddma.dev, "%s:%d Unable to fetch desc\n",
__func__, __LINE__);

if (!first)
return NULL;

spin_lock_irqsave(&pl330->pool_lock, flags);

while (!list_empty(&first->node)) {
desc = list_entry(first->node.next,
struct dma_pl330_desc, node);
list_move_tail(&desc->node, &pl330->desc_pool);
}

list_move_tail(&first->node, &pl330->desc_pool);

spin_unlock_irqrestore(&pl330->pool_lock, flags);

return NULL;
}

switch (direction) {
case DMA_MEM_TO_DEV:
desc->rqcfg.src_inc = 1;
desc->rqcfg.dst_inc = 0;
src = dma_addr;
dst = pch->fifo_addr;
break;
case DMA_DEV_TO_MEM:
desc->rqcfg.src_inc = 0;
desc->rqcfg.dst_inc = 1;
src = pch->fifo_addr;
dst = dma_addr;
break;
default:
break;
}

desc->rqtype = direction;
desc->rqcfg.brst_size = pch->burst_sz;

if (pl330->peripherals_req_type == BURST)
desc->rqcfg.brst_len = pch->burst_len;
else
desc->rqcfg.brst_len = 1;

desc->bytes_requested = period_len;
fill_px(&desc->px, dst, src, period_len);

if (!first)
first = desc;
else
list_add_tail(&desc->node, &first->node);
desc = pl330_get_desc(pch);
if (!desc) {
dev_err(pch->dmac->ddma.dev, "%s:%d Unable to fetch desc\n",
__func__, __LINE__);
return NULL;
}

dma_addr += period_len;
switch (direction) {
case DMA_MEM_TO_DEV:
desc->rqcfg.src_inc = 1;
desc->rqcfg.dst_inc = 0;
src = dma_addr;
dst = pch->fifo_addr;
break;
case DMA_DEV_TO_MEM:
desc->rqcfg.src_inc = 0;
desc->rqcfg.dst_inc = 1;
src = pch->fifo_addr;
dst = dma_addr;
break;
default:
break;
}

if (!desc)
return NULL;
desc->rqtype = direction;
desc->rqcfg.brst_size = pch->burst_sz;
desc->rqcfg.brst_len = pch->burst_len;
desc->bytes_requested = len;
fill_px(&desc->px, dst, src, period_len);

pch->cyclic = true;
desc->cyclic = true;
desc->num_periods = len / period_len;
desc->txd.flags = flags;

return &desc->txd;
Expand Down

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