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Commit ada8d4a5 authored by Mika Westerberg's avatar Mika Westerberg Committed by Tony Lindgren
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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: default avatarMika Westerberg <ext-mika.1.westerberg@nokia.com>
Acked-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: default avatarTony Lindgren <tony@atomide.com>
parent ad57c394

arch/arm/plat-omap/dma.c

+19 −8
Original line number Diff line number Diff line
@@ -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;