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dma40: ensure event lines get enabled

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The controller sometimes fails to register the enable of the event line when
both src and dst event lines are used on the same logical channel.  Implement
the recommended software workaround, which is to retry the write until it
works.

Acked-by: Per Forlin <per.forlin@stericsson.com>
Acked-by: Jonas Aaberg <jonas.aberg@stericsson.com>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Rabin Vincent 2011-01-25 11:18:05 +01:00 committed by Dan Williams
parent cb9ab2d8e4
commit 262d2915d4
1 changed files with 46 additions and 17 deletions
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63
drivers/dma/ste_dma40.c
View file

@ -303,6 +303,11 @@ struct d40_reg_val {
unsigned int val;
};
static struct device *chan2dev(struct d40_chan *d40c)
{
return &d40c->chan.dev->device;
}
static int d40_pool_lli_alloc(struct d40_desc *d40d,
int lli_len, bool is_log)
{
@ -701,17 +706,46 @@ static void d40_term_all(struct d40_chan *d40c)
d40c->busy = false;
}
static void __d40_config_set_event(struct d40_chan *d40c, bool enable,
u32 event, int reg)
{
void __iomem *addr = d40c->base->virtbase + D40_DREG_PCBASE
+ d40c->phy_chan->num * D40_DREG_PCDELTA + reg;
int tries;
if (!enable) {
writel((D40_DEACTIVATE_EVENTLINE << D40_EVENTLINE_POS(event))
| ~D40_EVENTLINE_MASK(event), addr);
return;
}
/*
* The hardware sometimes doesn't register the enable when src and dst
* event lines are active on the same logical channel. Retry to ensure
* it does. Usually only one retry is sufficient.
*/
tries = 100;
while (--tries) {
writel((D40_ACTIVATE_EVENTLINE << D40_EVENTLINE_POS(event))
| ~D40_EVENTLINE_MASK(event), addr);
if (readl(addr) & D40_EVENTLINE_MASK(event))
break;
}
if (tries != 99)
dev_dbg(chan2dev(d40c),
"[%s] workaround enable S%cLNK (%d tries)\n",
__func__, reg == D40_CHAN_REG_SSLNK ? 'S' : 'D',
100 - tries);
WARN_ON(!tries);
}
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
val = D40_DEACTIVATE_EVENTLINE;
spin_lock_irqsave(&d40c->phy_chan->lock, flags);
/* Enable event line connected to device (or memcpy) */
@ -719,20 +753,15 @@ static void d40_config_set_event(struct d40_chan *d40c, bool do_enable)
(d40c->dma_cfg.dir == STEDMA40_PERIPH_TO_PERIPH)) {
u32 event = D40_TYPE_TO_EVENT(d40c->dma_cfg.src_dev_type);
writel((val << D40_EVENTLINE_POS(event)) |
~D40_EVENTLINE_MASK(event),
d40c->base->virtbase + D40_DREG_PCBASE +
d40c->phy_chan->num * D40_DREG_PCDELTA +
D40_CHAN_REG_SSLNK);
__d40_config_set_event(d40c, do_enable, event,
D40_CHAN_REG_SSLNK);
}
if (d40c->dma_cfg.dir != STEDMA40_PERIPH_TO_MEM) {
u32 event = D40_TYPE_TO_EVENT(d40c->dma_cfg.dst_dev_type);
writel((val << D40_EVENTLINE_POS(event)) |
~D40_EVENTLINE_MASK(event),
d40c->base->virtbase + D40_DREG_PCBASE +
d40c->phy_chan->num * D40_DREG_PCDELTA +
D40_CHAN_REG_SDLNK);
__d40_config_set_event(d40c, do_enable, event,
D40_CHAN_REG_SDLNK);
}
spin_unlock_irqrestore(&d40c->phy_chan->lock, flags);