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usb: musb: workaround MUSB DMA_INTR sometimes reads zero 

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>
This commit is contained in:
Anand Gadiyar 2009-12-28 13:40:36 +02:00 committed by Greg Kroah-Hartman
parent 452f039437
commit f933a0c0fe
1 changed files with 22 additions and 3 deletions
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25
drivers/usb/musb/musbhsdma.c
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@ -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 *)