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authorMichael Ellerman <michael@ellerman.id.au>2008-01-25 16:59:14 +1100
committerPaul Mackerras <paulus@samba.org>2008-02-06 16:30:00 +1100
commitde4c928b843063b7079c35c950c1d38c559fa0cb (patch)
tree59c3f70d0047bef6c68bc7d514175c9d6378ec2c /arch/powerpc/platforms/cell/axon_msi.c
parente4347dfb580e0172185cb38529266ecf3b4d0baa (diff)
[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/cell/axon_msi.c')
-rw-r--r--arch/powerpc/platforms/cell/axon_msi.c21
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 ea3dc8c64a38..b9a97c4ae15a 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:

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