diff --git a/arch/powerpc/platforms/cell/axon_msi.c b/arch/powerpc/platforms/cell/axon_msi.c index 896548ba1ca1..442cf36aa172 100644 --- a/arch/powerpc/platforms/cell/axon_msi.c +++ b/arch/powerpc/platforms/cell/axon_msi.c @@ -95,6 +95,7 @@ static void axon_msi_cascade(unsigned int irq, struct irq_desc *desc) struct axon_msic *msic = get_irq_data(irq); u32 write_offset, msi; int idx; + int retry = 0; write_offset = dcr_read(msic->dcr_host, MSIC_WRITE_OFFSET_REG); pr_debug("axon_msi: original write_offset 0x%x\n", write_offset); @@ -102,7 +103,7 @@ static void axon_msi_cascade(unsigned int irq, struct irq_desc *desc) /* write_offset doesn't wrap properly, so we have to mask it */ write_offset &= MSIC_FIFO_SIZE_MASK; - while (msic->read_offset != write_offset) { + while (msic->read_offset != write_offset && retry < 100) { idx = msic->read_offset / sizeof(__le32); msi = le32_to_cpu(msic->fifo_virt[idx]); msi &= 0xFFFF; @@ -110,13 +111,37 @@ static void axon_msi_cascade(unsigned int irq, struct irq_desc *desc) pr_debug("axon_msi: woff %x roff %x msi %x\n", write_offset, msic->read_offset, msi); + if (msi < NR_IRQS && irq_map[msi].host == msic->irq_host) { + generic_handle_irq(msi); + msic->fifo_virt[idx] = cpu_to_le32(0xffffffff); + } else { + /* + * Reading the MSIC_WRITE_OFFSET_REG does not + * reliably flush the outstanding DMA to the + * FIFO buffer. Here we were reading stale + * data, so we need to retry. + */ + udelay(1); + retry++; + pr_debug("axon_msi: invalid irq 0x%x!\n", msi); + continue; + } + + if (retry) { + pr_debug("axon_msi: late irq 0x%x, retry %d\n", + msi, retry); + retry = 0; + } + msic->read_offset += MSIC_FIFO_ENTRY_SIZE; msic->read_offset &= MSIC_FIFO_SIZE_MASK; + } - if (msi < NR_IRQS && irq_map[msi].host == msic->irq_host) - generic_handle_irq(msi); - else - pr_debug("axon_msi: invalid irq 0x%x!\n", msi); + if (retry) { + printk(KERN_WARNING "axon_msi: irq timed out\n"); + + msic->read_offset += MSIC_FIFO_ENTRY_SIZE; + msic->read_offset &= MSIC_FIFO_SIZE_MASK; } desc->chip->eoi(irq); @@ -364,6 +389,7 @@ static int axon_msi_probe(struct of_device *device, dn->full_name); goto out_free_fifo; } + memset(msic->fifo_virt, 0xff, MSIC_FIFO_SIZE_BYTES); msic->irq_host = irq_alloc_host(dn, IRQ_HOST_MAP_NOMAP, NR_IRQS, &msic_host_ops, 0);