On 2015/7/8 21:22, Robin Murphy wrote:
> On 07/07/15 04:30, Zhen Lei wrote:
>> This patch support a master with multiple stream IDs, but doesn't support a
>> master behinds more than one SMMUs.
>
> This should probably include a binding documentation update to make it clear
> what values of #iommu-cells the driver supports in what circumstances, and
> that the cells themselves should contain raw
> stream IDs.
OK.
>
>> Signed-off-by: Zhen Lei <thunder.leiz...@huawei.com>
>> ---
>> drivers/iommu/arm-smmu-v3.c | 39 +++++++++++++++++++++++++++++++++++++--
>> 1 file changed, 37 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/iommu/arm-smmu-v3.c b/drivers/iommu/arm-smmu-v3.c
>> index 274d059..582cd1e 100644
>> --- a/drivers/iommu/arm-smmu-v3.c
>> +++ b/drivers/iommu/arm-smmu-v3.c
>> @@ -30,6 +30,7 @@
>> #include <linux/of_address.h>
>> #include <linux/pci.h>
>> #include <linux/platform_device.h>
>> +#include <linux/amba/bus.h>
>> #include <linux/of_iommu.h>
>> #include <linux/of_platform.h>
>>
>> @@ -1928,9 +1929,35 @@ static int arm_smmu_of_xlate(struct device *dev,
>> struct of_phandle_args *args)
>> return -EINVAL;
>> }
>>
>> - /* We only support PCI, for now */
>> if (!dev_is_pci(dev)) {
>> - return -ENODEV;
>> + int i;
>> + struct iommu_group *group;
>> +
>> + group = iommu_group_get(dev);
>> + if (!group) {
>> + group = iommu_group_alloc();
>> + if (IS_ERR(group)) {
>> + dev_err(dev, "failed to allocate IOMMU group\n");
>> + return PTR_ERR(group);
>> + }
>> +
>> + ret = iommu_group_add_device(group, dev);
>> + if (ret) {
>> + dev_err(dev, "failed to add device into IOMMU group\n");
>> + return PTR_ERR(group);
>
> This leaks the group.
OK, I got it. Thanks.
>
>> + }
>> + }
>> + iommu_group_put(group);
>> +
>> + for (i = 0; i < args->args_count; i++) {
>
> I'm dubious of the value of looping here - having n>1 #iommu-cells per
> phandle means that every platform device behind one SMMU must have the same
> number of stream IDs, or you still have to have
> repeated phandles for every device with some greater multiple of n stream IDs
> each, but ruling out any device with <n. I'm not sure how realistic that is,
> and whether there's any real benefit beyond
> saving a handful of bytes in the DTB.
As you mentioned before, a master with two streamIDs can be written as
below(This is also mentioned in
Documentation\devicetree\bindings\iommu\iommu.txt):
#iommu-cells = <1>;
iommus = <&{/iommu} 23>, <&{/iommu} 24>;
On my hardware platform, a master only have one streamID. But I tested two
cases:
#iommu-cells = <1>;
1. iommus = <&smmu0 good-sid>, <&smmu0 bad-sid>;
2. iommus = <&smmu0 bad-sid>, <&smmu0 good-sid>;
All of these two cases worked well.
Well, if each master contains two streamIDs(or more but equal), this for loop
is needed.
>
>> + ret = arm_smmu_add_device(dev, args->args[i]);
>> + if (ret) {
>> + dev_err(dev,
>> + "failed to add sid=%d into SMMU\n",
>> + args->args[i]);
>> + return ret;
>> + }
>> + }
>> } else {
>> u32 sid;
>> struct device_node *of_root;
>> @@ -2725,6 +2752,14 @@ static int __init arm_smmu_init(void)
>> if (ret)
>> return ret;
>>
>> + if (!iommu_present(&platform_bus_type))
>> + bus_set_iommu(&platform_bus_type, &arm_smmu_ops);
>> +
>> +#ifdef CONFIG_ARM_AMBA
>> + if (!iommu_present(&amba_bustype))
>> + bus_set_iommu(&amba_bustype, &arm_smmu_ops);
>> +#endif
>> +
>> return bus_set_iommu(&pci_bus_type, &arm_smmu_ops);
>> }
>>
>> --
>> 1.8.0
>>
>>
>> _______________________________________________
>> iommu mailing list
>> iommu@lists.linux-foundation.org
>> https://lists.linuxfoundation.org/mailman/listinfo/iommu
>>
>
>
> .
>
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