Hi Robin, On Thu, May 16, 2019 at 3:00 PM Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx> wrote: > > Few Qualcomm platforms such as, sdm845 have an additional outer > cache called as System cache, aka. Last level cache (LLC) that > allows non-coherent devices to upgrade to using caching. > This cache sits right before the DDR, and is tightly coupled > with the memory controller. The clients using this cache request > their slices from this system cache, make it active, and can then > start using it. > > There is a fundamental assumption that non-coherent devices can't > access caches. This change adds an exception where they *can* use > some level of cache despite still being non-coherent overall. > The coherent devices that use cacheable memory, and CPU make use of > this system cache by default. > > Looking at memory types, we have following - > a) Normal uncached :- MAIR 0x44, inner non-cacheable, > outer non-cacheable; > b) Normal cached :- MAIR 0xff, inner read write-back non-transient, > outer read write-back non-transient; > attribute setting for coherenet I/O devices. > and, for non-coherent i/o devices that can allocate in system cache > another type gets added - > c) Normal sys-cached :- MAIR 0xf4, inner non-cacheable, > outer read write-back non-transient > > Coherent I/O devices use system cache by marking the memory as > normal cached. > Non-coherent I/O devices should mark the memory as normal > sys-cached in page tables to use system cache. > > Signed-off-by: Vivek Gautam <vivek.gautam@xxxxxxxxxxxxxx> > --- Let me know if there's more to improve on this patch. Best regards Vivek > > V3 version of this patch and related series can be found at [1]. > V4 of this patch is available at [2]. > > The example usage of how a smmu master can make use of this protection > flag and set the correct memory attributes to start using system cache, > can be found at [3]; and here at [3] IOMMU_UPSTREAM_HINT is same as > IOMMU_QCOM_SYS_CACHE. > > Changes since v4: > - Changed ARM_LPAE_MAIR_ATTR_QCOM_SYS_CACHE to > ARM_LPAE_MAIR_ATTR_INC_OWBRWA. > - Changed ARM_LPAE_MAIR_ATTR_IDX_QCOM_SYS_CACHE to > ARM_LPAE_MAIR_ATTR_IDX_INC_OCACHE. > - Added comments to iommu protection flag - IOMMU_QCOM_SYS_CACHE. > > Changes since v3: > - Dropping support to cache i/o page tables to system cache. Getting support > for data buffers is the first step. > Removed io-pgtable quirk and related change to add domain attribute. > > Glmark2 numbers on SDM845 based cheza board: > > S.No.| with LLC support | without LLC support > | for data buffers | > --------------------------------------------------- > 1 | 4480; 72.3fps | 4042; 65.2fps > 2 | 4500; 72.6fps | 4039; 65.1fps > 3 | 4523; 72.9fps | 4106; 66.2fps > 4 | 4489; 72.4fps | 4104; 66.2fps > 5 | 4518; 72.9fps | 4072; 65.7fps > > [1] https://patchwork.kernel.org/cover/10772629/ > [2] https://lore.kernel.org/patchwork/patch/1072936/ > [3] https://patchwork.kernel.org/patch/10302791/ > > drivers/iommu/io-pgtable-arm.c | 9 ++++++++- > include/linux/iommu.h | 6 ++++++ > 2 files changed, 14 insertions(+), 1 deletion(-) > > diff --git a/drivers/iommu/io-pgtable-arm.c b/drivers/iommu/io-pgtable-arm.c > index 4e21efbc4459..2454ac11aa97 100644 > --- a/drivers/iommu/io-pgtable-arm.c > +++ b/drivers/iommu/io-pgtable-arm.c > @@ -167,10 +167,12 @@ > #define ARM_LPAE_MAIR_ATTR_MASK 0xff > #define ARM_LPAE_MAIR_ATTR_DEVICE 0x04 > #define ARM_LPAE_MAIR_ATTR_NC 0x44 > +#define ARM_LPAE_MAIR_ATTR_INC_OWBRWA 0xf4 > #define ARM_LPAE_MAIR_ATTR_WBRWA 0xff > #define ARM_LPAE_MAIR_ATTR_IDX_NC 0 > #define ARM_LPAE_MAIR_ATTR_IDX_CACHE 1 > #define ARM_LPAE_MAIR_ATTR_IDX_DEV 2 > +#define ARM_LPAE_MAIR_ATTR_IDX_INC_OCACHE 3 > > #define ARM_MALI_LPAE_TTBR_ADRMODE_TABLE (3u << 0) > #define ARM_MALI_LPAE_TTBR_READ_INNER BIT(2) > @@ -470,6 +472,9 @@ static arm_lpae_iopte arm_lpae_prot_to_pte(struct arm_lpae_io_pgtable *data, > else if (prot & IOMMU_CACHE) > pte |= (ARM_LPAE_MAIR_ATTR_IDX_CACHE > << ARM_LPAE_PTE_ATTRINDX_SHIFT); > + else if (prot & IOMMU_QCOM_SYS_CACHE) > + pte |= (ARM_LPAE_MAIR_ATTR_IDX_INC_OCACHE > + << ARM_LPAE_PTE_ATTRINDX_SHIFT); > } > > if (prot & IOMMU_NOEXEC) > @@ -857,7 +862,9 @@ arm_64_lpae_alloc_pgtable_s1(struct io_pgtable_cfg *cfg, void *cookie) > (ARM_LPAE_MAIR_ATTR_WBRWA > << ARM_LPAE_MAIR_ATTR_SHIFT(ARM_LPAE_MAIR_ATTR_IDX_CACHE)) | > (ARM_LPAE_MAIR_ATTR_DEVICE > - << ARM_LPAE_MAIR_ATTR_SHIFT(ARM_LPAE_MAIR_ATTR_IDX_DEV)); > + << ARM_LPAE_MAIR_ATTR_SHIFT(ARM_LPAE_MAIR_ATTR_IDX_DEV)) | > + (ARM_LPAE_MAIR_ATTR_INC_OWBRWA > + << ARM_LPAE_MAIR_ATTR_SHIFT(ARM_LPAE_MAIR_ATTR_IDX_INC_OCACHE)); > > cfg->arm_lpae_s1_cfg.mair[0] = reg; > cfg->arm_lpae_s1_cfg.mair[1] = 0; > diff --git a/include/linux/iommu.h b/include/linux/iommu.h > index a815cf6f6f47..8ee3fbaf5855 100644 > --- a/include/linux/iommu.h > +++ b/include/linux/iommu.h > @@ -41,6 +41,12 @@ > * if the IOMMU page table format is equivalent. > */ > #define IOMMU_PRIV (1 << 5) > +/* > + * Non-coherent masters on few Qualcomm SoCs can use this page protection flag > + * to set correct cacheability attributes to use an outer level of cache - > + * last level cache, aka system cache. > + */ > +#define IOMMU_QCOM_SYS_CACHE (1 << 6) > > struct iommu_ops; > struct iommu_group; > -- > QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member > of Code Aurora Forum, hosted by The Linux Foundation > > _______________________________________________ > iommu mailing list > iommu@xxxxxxxxxxxxxxxxxxxxxxxxxx > https://lists.linuxfoundation.org/mailman/listinfo/iommu -- QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation
