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From: Linus Walleij on 20 Jun 2010 17:30
From: Jonas Aaberg <jonas.aberg(a)stericsson.com>

Avoid doing unnessecary suspend when modifying logical channels.

Signed-off-by: Jonas Aaberg <jonas.aberg(a)stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij(a)stericsson.com>
---
drivers/dma/ste_dma40.c | 39 +++++++--------------------------------
1 files changed, 7 insertions(+), 32 deletions(-)

diff --git a/drivers/dma/ste_dma40.c b/drivers/dma/ste_dma40.c
index ebffb53..abbc1b6 100644
--- a/drivers/dma/ste_dma40.c
+++ b/drivers/dma/ste_dma40.c
@@ -595,6 +595,7 @@ static void d40_config_set_event(struct d40_chan *d40c, bool do_enable)
u32 val;
unsigned long flags;

+ /* Notice, that disable requires the physical channel to be stopped */
if (do_enable)
val = D40_ACTIVATE_EVENTLINE;
else
@@ -740,18 +741,10 @@ static dma_cookie_t d40_tx_submit(struct dma_async_tx_descriptor *tx)

static int d40_start(struct d40_chan *d40c)
{
- int err;
-
- if (d40c->log_num != D40_PHY_CHAN) {
- err = d40_channel_execute_command(d40c, D40_DMA_SUSPEND_REQ);
- if (err)
- return err;
+ if (d40c->log_num != D40_PHY_CHAN)
d40_config_set_event(d40c, true);
- }
-
- err = d40_channel_execute_command(d40c, D40_DMA_RUN);

- return err;
+ return d40_channel_execute_command(d40c, D40_DMA_RUN);
}

static struct d40_desc *d40_queue_start(struct d40_chan *d40c)
@@ -1340,7 +1333,6 @@ static bool d40_is_paused(struct d40_chan *d40c)
void __iomem *active_reg;
u32 status;
u32 event;
- int res;

spin_lock_irqsave(&d40c->lock, flags);

@@ -1359,10 +1351,6 @@ static bool d40_is_paused(struct d40_chan *d40c)
goto _exit;
}

- res = d40_channel_execute_command(d40c, D40_DMA_SUSPEND_REQ);
- if (res != 0)
- goto _exit;
-
if (d40c->dma_cfg.dir == STEDMA40_MEM_TO_PERIPH ||
d40c->dma_cfg.dir == STEDMA40_MEM_TO_MEM)
event = D40_TYPE_TO_EVENT(d40c->dma_cfg.dst_dev_type);
@@ -1379,12 +1367,6 @@ static bool d40_is_paused(struct d40_chan *d40c)

if (status != D40_DMA_RUN)
is_paused = true;
-
- /* Resume the other logical channels if any */
- if (d40_chan_has_events(d40c))
- res = d40_channel_execute_command(d40c,
- D40_DMA_RUN);
-
_exit:
spin_unlock_irqrestore(&d40c->lock, flags);
return is_paused;
@@ -1430,20 +1412,13 @@ static int d40_resume(struct dma_chan *chan)

spin_lock_irqsave(&d40c->lock, flags);

- if (d40c->log_num != D40_PHY_CHAN) {
- res = d40_channel_execute_command(d40c, D40_DMA_SUSPEND_REQ);
- if (res)
- goto out;
-
- /* If bytes left to transfer or linked tx resume job */
- if (d40_residue(d40c) || d40_tx_is_linked(d40c)) {
+ /* If bytes left to transfer or linked tx resume job */
+ if (d40_residue(d40c) || d40_tx_is_linked(d40c)) {
+ if (d40c->log_num != D40_PHY_CHAN)
d40_config_set_event(d40c, true);
- res = d40_channel_execute_command(d40c, D40_DMA_RUN);
- }
- } else if (d40_residue(d40c) || d40_tx_is_linked(d40c))
res = d40_channel_execute_command(d40c, D40_DMA_RUN);
+ }

-out:
spin_unlock_irqrestore(&d40c->lock, flags);
return res;
}
--
1.6.3.3

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Next: [PATCH 17/19] DMAENGINE: ste_dma40: no disabled phy channels on ux500