usb: musb: workaround MUSB DMA_INTR sometimes reads zero (f933a0c0) · Commits · 戴 / test

MUSB DMA_INTR register may sometimes read zero when infact there was a pending interrupt. Workaround this by reading the DMA_COUNT values for all enabled channels when this condition occurs. Flag these channels as the ones needing to be serviced. Additionally, the absence of a debug print meant we would never catch a spurious DMA interrupt in MUSB. So this patch adds a debug print in the IRQ handler. Signed-off-by:

Anand Gadiyar <gadiyar@ti.com> Cc: Ajay Kumar Gupta <ajay.gupta@ti.com> Cc: David Brownell <dbrownell@users.sourceforge.net> Cc: Sergei Shtylyov <sshtylyov@ru.mvista.com> Cc: Vikram Pandita <vikram.pandita@ti.com> Signed-off-by:

Felipe Balbi <felipe.balbi@nokia.com> Signed-off-by:

Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/musb/musbhsdma.c

+22 −3

Original line number	Diff line number	Diff line
		@@ -250,20 +250,39 @@ static irqreturn_t dma_controller_irq(int irq, void *private_data)
		u8 bchannel;
		u8 int_hsdma;

		u32 addr;
		u32 addr, count;
		u16 csr;

		spin_lock_irqsave(&musb->lock, flags);

		int_hsdma = musb_readb(mbase, MUSB_HSDMA_INTR);
		if (!int_hsdma)
		goto done;

		#ifdef CONFIG_BLACKFIN
		/* Clear DMA interrupt flags */
		musb_writeb(mbase, MUSB_HSDMA_INTR, int_hsdma);
		#endif

		if (!int_hsdma) {
		DBG(2, "spurious DMA irq\n");

		for (bchannel = 0; bchannel < MUSB_HSDMA_CHANNELS; bchannel++) {
		musb_channel = (struct musb_dma_channel *)
		&(controller->channel[bchannel]);
		channel = &musb_channel->channel;
		if (channel->status == MUSB_DMA_STATUS_BUSY) {
		count = musb_read_hsdma_count(mbase, bchannel);

		if (count == 0)
		int_hsdma \|= (1 << bchannel);
		}
		}

		DBG(2, "int_hsdma = 0x%x\n", int_hsdma);

		if (!int_hsdma)
		goto done;
		}

		for (bchannel = 0; bchannel < MUSB_HSDMA_CHANNELS; bchannel++) {
		if (int_hsdma & (1 << bchannel)) {
		musb_channel = (struct musb_dma_channel *)

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