From f933a0c0fe0ea5f49a35bcd45e3e4850e0606cba Mon Sep 17 00:00:00 2001 From: Anand Gadiyar Date: Mon, 28 Dec 2009 13:40:36 +0200 Subject: [PATCH] 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 Cc: Ajay Kumar Gupta Cc: David Brownell Cc: Sergei Shtylyov Cc: Vikram Pandita Signed-off-by: Felipe Balbi Signed-off-by: Greg Kroah-Hartman --- drivers/usb/musb/musbhsdma.c | 25 ++++++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/drivers/usb/musb/musbhsdma.c b/drivers/usb/musb/musbhsdma.c index a237550f91b..2fa7d5c00f3 100644 --- a/drivers/usb/musb/musbhsdma.c +++ b/drivers/usb/musb/musbhsdma.c @@ -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 *) -- 2.11.4.GIT