On Thu, Oct 10, 2013 at 12:12:17PM -0400, Will Deacon wrote:
On Wed, Oct 09, 2013 at 11:38:01PM +0100, Andreas Herrmann wrote:
drivers/iommu/arm-smmu.c | 53
++
1 file changed, 53 insertions(+)
diff --git a/drivers/iommu/arm-smmu.c b/drivers/iommu/arm-smmu.c
index 478c8ad..87239e8 100644
--- a/drivers/iommu/arm-smmu.c
+++ b/drivers/iommu/arm-smmu.c
@@ -46,6 +46,7 @@
#include linux/amba/bus.h
#include asm/pgalloc.h
+#include asm/dma-iommu.h
/* Driver options */
#define ARM_SMMU_OPT_ISOLATE_DEVICES (1 0)
@@ -1983,6 +1984,56 @@ static int arm_smmu_device_remove(struct
platform_device *pdev)
return 0;
}
+static int arm_smmu_device_notifier(struct notifier_block *nb,
+ unsigned long action, void *data)
+{
+ struct device *dev = data;
+ struct dma_iommu_mapping *mapping;
+ struct arm_smmu_device *smmu;
+ void __iomem *gr0_base;
+ u32 cr0;
+ int ret;
+
+ switch (action) {
+ case BUS_NOTIFY_BIND_DRIVER:
+
+ arm_smmu_add_device(dev);
+ smmu = dev-archdata.iommu;
+ if (!smmu || !(smmu-options ARM_SMMU_OPT_ISOLATE_DEVICES))
+ break;
+
+ mapping = arm_iommu_create_mapping(platform_bus_type,
+ 0, SZ_128M, 0);
We need to find a better way of doing this; I'm really not happy hardcoding
that size limit and hoping for the best.
Hmm, seems that mid-term we should try to enlarge this area by another
128M if a mapping fails due to this limit. I think Joerg's amd_iommu
driver does this.
(But at the same time I'd prefer to start with even a hardcoded value,
or to simply introduce some option to set this fixed limit per master
or per smmu.)
+ if (IS_ERR(mapping)) {
+ ret = PTR_ERR(mapping);
+ dev_info(dev, arm_iommu_create_mapping failed\n);
+ break;
+ }
+
+ ret = arm_iommu_attach_device(dev, mapping);
+ if (ret 0) {
+ dev_info(dev, arm_iommu_attach_device failed\n);
+ arm_iommu_release_mapping(mapping);
+ }
+
+ gr0_base = ARM_SMMU_GR0_NS(smmu);
+ cr0 = readl_relaxed(gr0_base + ARM_SMMU_GR0_sCR0);
+ cr0 |= sCR0_USFCFG;
+ writel(cr0, gr0_base + ARM_SMMU_GR0_sCR0);
Why do you need to enable this flag? If no mapping is found, that means *we*
screwed something up, so we should report that and not rely on the hardware
potentially raising a fault. I also prefer to allow passthrough for devices
that don't hit in the stream table, because it allows people to ignore the
SMMU
in their DT if they want to.
You are right that's not strictly required for device isolation.
(but it helped to learn about relevant stream-ids that were not
covered by by my DTS ;-)
Andreas
___
iommu mailing list
iommu@lists.linux-foundation.org
https://lists.linuxfoundation.org/mailman/listinfo/iommu
