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| author | Michael Ellerman <michael@ellerman.id.au> | 2008-01-25 16:59:14 +1100 |
|---|---|---|
| committer | Paul Mackerras <paulus@samba.org> | 2008-02-06 16:30:00 +1100 |
| commit | de4c928b843063b7079c35c950c1d38c559fa0cb (patch) | |
| tree | 59c3f70d0047bef6c68bc7d514175c9d6378ec2c /arch/powerpc/platforms | |
| parent | e4347dfb580e0172185cb38529266ecf3b4d0baa (diff) | |
| download | op-kernel-dev-de4c928b843063b7079c35c950c1d38c559fa0cb.zip op-kernel-dev-de4c928b843063b7079c35c950c1d38c559fa0cb.tar.gz | |
[POWERPC] Avoid DMA exception when using axon_msi with IOMMU
There's a brown-paper-bag bug in axon_msi, we pass the address of our
FIFO directly to the hardware, without DMA mapping it. This leads to
DMA exceptions if you enable MSI & the IOMMU.
The fix is to correctly DMA map the fifo, dma_alloc_coherent() does
what we want - and we need to track the virt & phys addresses.
Signed-off-by: Michael Ellerman <michael@ellerman.id.au>
Acked-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Paul Mackerras <paulus@samba.org>
Diffstat (limited to 'arch/powerpc/platforms')
| -rw-r--r-- | arch/powerpc/platforms/cell/axon_msi.c | 21 |
1 files changed, 10 insertions, 11 deletions
diff --git a/arch/powerpc/platforms/cell/axon_msi.c b/arch/powerpc/platforms/cell/axon_msi.c index ea3dc8c..b9a97c4 100644 --- a/arch/powerpc/platforms/cell/axon_msi.c +++ b/arch/powerpc/platforms/cell/axon_msi.c @@ -65,7 +65,8 @@ struct axon_msic { struct irq_host *irq_host; - __le32 *fifo; + __le32 *fifo_virt; + dma_addr_t fifo_phys; dcr_host_t dcr_host; u32 read_offset; }; @@ -91,7 +92,7 @@ static void axon_msi_cascade(unsigned int irq, struct irq_desc *desc) while (msic->read_offset != write_offset) { idx = msic->read_offset / sizeof(__le32); - msi = le32_to_cpu(msic->fifo[idx]); + msi = le32_to_cpu(msic->fifo_virt[idx]); msi &= 0xFFFF; pr_debug("axon_msi: woff %x roff %x msi %x\n", @@ -306,7 +307,6 @@ static int axon_msi_shutdown(struct of_device *device) static int axon_msi_probe(struct of_device *device, const struct of_device_id *device_id) { - struct page *page; struct device_node *dn = device->node; struct axon_msic *msic; unsigned int virq; @@ -338,16 +338,14 @@ static int axon_msi_probe(struct of_device *device, goto out_free_msic; } - page = alloc_pages_node(of_node_to_nid(dn), GFP_KERNEL, - get_order(MSIC_FIFO_SIZE_BYTES)); - if (!page) { + msic->fifo_virt = dma_alloc_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES, + &msic->fifo_phys, GFP_KERNEL); + if (!msic->fifo_virt) { printk(KERN_ERR "axon_msi: couldn't allocate fifo for %s\n", dn->full_name); goto out_free_msic; } - msic->fifo = page_address(page); - msic->irq_host = irq_alloc_host(of_node_get(dn), IRQ_HOST_MAP_NOMAP, NR_IRQS, &msic_host_ops, 0); if (!msic->irq_host) { @@ -370,9 +368,9 @@ static int axon_msi_probe(struct of_device *device, pr_debug("axon_msi: irq 0x%x setup for axon_msi\n", virq); /* Enable the MSIC hardware */ - msic_dcr_write(msic, MSIC_BASE_ADDR_HI_REG, (u64)msic->fifo >> 32); + msic_dcr_write(msic, MSIC_BASE_ADDR_HI_REG, msic->fifo_phys >> 32); msic_dcr_write(msic, MSIC_BASE_ADDR_LO_REG, - (u64)msic->fifo & 0xFFFFFFFF); + msic->fifo_phys & 0xFFFFFFFF); msic_dcr_write(msic, MSIC_CTRL_REG, MSIC_CTRL_IRQ_ENABLE | MSIC_CTRL_ENABLE | MSIC_CTRL_FIFO_SIZE); @@ -390,7 +388,8 @@ static int axon_msi_probe(struct of_device *device, out_free_host: kfree(msic->irq_host); out_free_fifo: - __free_pages(virt_to_page(msic->fifo), get_order(MSIC_FIFO_SIZE_BYTES)); + dma_free_coherent(&device->dev, MSIC_FIFO_SIZE_BYTES, msic->fifo_virt, + msic->fifo_phys); out_free_msic: kfree(msic); out: |
