lkml.org 
[lkml]   [2020]   [Nov]   [11]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCHv7 2/7] iommu/arm-smmu: Add domain attribute for system cache
On 2020-11-10 17:48, Will Deacon wrote:
> On Fri, Oct 30, 2020 at 02:53:09PM +0530, Sai Prakash Ranjan wrote:
>> Add iommu domain attribute for using system cache aka last level
>> cache by client drivers like GPU to set right attributes for caching
>> the hardware pagetables into the system cache.
>>
>> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org>
>> ---
>> drivers/iommu/arm/arm-smmu/arm-smmu.c | 17 +++++++++++++++++
>> drivers/iommu/arm/arm-smmu/arm-smmu.h | 1 +
>> include/linux/iommu.h | 1 +
>> 3 files changed, 19 insertions(+)
>>
>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> b/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> index b1cf8f0abc29..070d13f80c7e 100644
>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.c
>> @@ -789,6 +789,9 @@ static int arm_smmu_init_domain_context(struct
>> iommu_domain *domain,
>> if (smmu_domain->non_strict)
>> pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_NON_STRICT;
>>
>> + if (smmu_domain->sys_cache)
>> + pgtbl_cfg.quirks |= IO_PGTABLE_QUIRK_SYS_CACHE;
>> +
>> pgtbl_ops = alloc_io_pgtable_ops(fmt, &pgtbl_cfg, smmu_domain);
>> if (!pgtbl_ops) {
>> ret = -ENOMEM;
>> @@ -1520,6 +1523,9 @@ static int arm_smmu_domain_get_attr(struct
>> iommu_domain *domain,
>> case DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE:
>> *(int *)data = smmu_domain->non_strict;
>> return 0;
>> + case DOMAIN_ATTR_SYS_CACHE:
>> + *((int *)data) = smmu_domain->sys_cache;
>> + return 0;
>> default:
>> return -ENODEV;
>> }
>> @@ -1551,6 +1557,17 @@ static int arm_smmu_domain_set_attr(struct
>> iommu_domain *domain,
>> else
>> smmu_domain->stage = ARM_SMMU_DOMAIN_S1;
>> break;
>> + case DOMAIN_ATTR_SYS_CACHE:
>> + if (smmu_domain->smmu) {
>> + ret = -EPERM;
>> + goto out_unlock;
>> + }
>> +
>> + if (*((int *)data))
>> + smmu_domain->sys_cache = true;
>> + else
>> + smmu_domain->sys_cache = false;
>> + break;
>> default:
>> ret = -ENODEV;
>> }
>> diff --git a/drivers/iommu/arm/arm-smmu/arm-smmu.h
>> b/drivers/iommu/arm/arm-smmu/arm-smmu.h
>> index 885840f3bec8..dfc44d806671 100644
>> --- a/drivers/iommu/arm/arm-smmu/arm-smmu.h
>> +++ b/drivers/iommu/arm/arm-smmu/arm-smmu.h
>> @@ -373,6 +373,7 @@ struct arm_smmu_domain {
>> struct mutex init_mutex; /* Protects smmu pointer */
>> spinlock_t cb_lock; /* Serialises ATS1* ops and TLB syncs */
>> struct iommu_domain domain;
>> + bool sys_cache;
>> };
>>
>> struct arm_smmu_master_cfg {
>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
>> index b95a6f8db6ff..4f4bb9c6f8f6 100644
>> --- a/include/linux/iommu.h
>> +++ b/include/linux/iommu.h
>> @@ -118,6 +118,7 @@ enum iommu_attr {
>> DOMAIN_ATTR_FSL_PAMUV1,
>> DOMAIN_ATTR_NESTING, /* two stages of translation */
>> DOMAIN_ATTR_DMA_USE_FLUSH_QUEUE,
>> + DOMAIN_ATTR_SYS_CACHE,
>
> I think you're trying to make this look generic, but it's really not.
> If we need to funnel io-pgtable quirks through domain attributes, then
> I
> think we should be open about that and add something like
> DOMAIN_ATTR_IO_PGTABLE_CFG which could take a struct of page-table
> configuration data for the domain (this could just be quirks initially,
> but maybe it's worth extending to take ias, oas and page size)
>

Actually the initial versions used DOMAIN_ATTR_QCOM_SYS_CACHE
to make it QCOM specific and not generic, I don't see anyone else
using this attribute, would that work?

Thanks,
Sai

--
QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a
member
of Code Aurora Forum, hosted by The Linux Foundation

\
 
 \ /
  Last update: 2020-11-11 07:41    [W:2.209 / U:0.044 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site