OMAP2/3/4: DMA: disable channel interrupts in omap_init_dma() (ada8d4a5) · Commits · 戴 / test

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>

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;

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