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OMAP2/3/4: DMA: disable channel interrupts in omap_init_dma() 

If we are softbooting another kernel using kexec, DMA controller state is not
known when we are performing omap_init_dma(). It is possible that some DMA
channels are already active. For example after kexec we get:

<4>IRQ 0020 for non-allocated DMAchannel 5
<4>IRQ 0020 for non-allocated DMAchannel 5
<4>IRQ 0020 for non-allocated DMAchannel 5
<4>IRQ 0020 for non-allocated DMAchannel 5
<4>IRQ 0020 for non-allocated DMAchannel 5

To prevent any weird things happening, we disable all channel interrupts during
init.

Signed-off-by: Mika Westerberg <ext-mika.1.westerberg@nokia.com>
Acked-by: Kevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
This commit is contained in:
Mika Westerberg 2010-05-14 12:05:25 -07:00 committed by Tony Lindgren
parent ad57c39482
commit ada8d4a5e2
1 changed files with 19 additions and 8 deletions
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27
arch/arm/plat-omap/dma.c
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@ -709,6 +709,21 @@ static inline void omap2_enable_irq_lch(int lch)
spin_unlock_irqrestore(&dma_chan_lock, flags);
}
static inline void omap2_disable_irq_lch(int lch)
{
u32 val;
unsigned long flags;
if (!cpu_class_is_omap2())
return;
spin_lock_irqsave(&dma_chan_lock, flags);
val = dma_read(IRQENABLE_L0);
val &= ~(1 << lch);
dma_write(val, IRQENABLE_L0);
spin_unlock_irqrestore(&dma_chan_lock, flags);
}
int omap_request_dma(int dev_id, const char *dev_name,
void (*callback)(int lch, u16 ch_status, void *data),
void *data, int *dma_ch_out)
@ -807,14 +822,7 @@ void omap_free_dma(int lch)
}
if (cpu_class_is_omap2()) {
u32 val;
spin_lock_irqsave(&dma_chan_lock, flags);
/* Disable interrupts */
val = dma_read(IRQENABLE_L0);
val &= ~(1 << lch);
dma_write(val, IRQENABLE_L0);
spin_unlock_irqrestore(&dma_chan_lock, flags);
omap2_disable_irq_lch(lch);
/* Clear the CSR register and IRQ status register */
dma_write(OMAP2_DMA_CSR_CLEAR_MASK, CSR(lch));
@ -2107,6 +2115,9 @@ static int __init omap_init_dma(void)
for (ch = 0; ch < dma_chan_count; ch++) {
omap_clear_dma(ch);
if (cpu_class_is_omap2())
omap2_disable_irq_lch(ch);
dma_chan[ch].dev_id = -1;
dma_chan[ch].next_lch = -1;