Messages in this thread | | | Date | Mon, 28 Sep 2020 17:56:55 +0530 | From | Sai Prakash Ranjan <> | Subject | Re: [PATCHv5 4/6] drm/msm/a6xx: Add support for using system cache(LLC) |
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Hi Jordan,
On 2020-09-23 20:33, Jordan Crouse wrote: > On Tue, Sep 22, 2020 at 11:48:17AM +0530, Sai Prakash Ranjan wrote: >> From: Sharat Masetty <smasetty@codeaurora.org> >> >> The last level system cache can be partitioned to 32 different >> slices of which GPU has two slices preallocated. One slice is >> used for caching GPU buffers and the other slice is used for >> caching the GPU SMMU pagetables. This talks to the core system >> cache driver to acquire the slice handles, configure the SCID's >> to those slices and activates and deactivates the slices upon >> GPU power collapse and restore. >> >> Some support from the IOMMU driver is also needed to make use >> of the system cache to set the right TCR attributes. GPU then >> has the ability to override a few cacheability parameters which >> it does to override write-allocate to write-no-allocate as the >> GPU hardware does not benefit much from it. >> >> DOMAIN_ATTR_SYS_CACHE is another domain level attribute used by the >> IOMMU driver to set the right attributes to cache the hardware >> pagetables into the system cache. >> >> Signed-off-by: Sharat Masetty <smasetty@codeaurora.org> >> [saiprakash.ranjan: fix to set attr before device attach to iommu and >> rebase] >> Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@codeaurora.org> >> --- >> drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 83 >> +++++++++++++++++++++++++ >> drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 4 ++ >> drivers/gpu/drm/msm/adreno/adreno_gpu.c | 17 +++++ >> 3 files changed, 104 insertions(+) >> >> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c >> b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c >> index 8915882e4444..151190ff62f7 100644 >> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c >> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c >> @@ -8,7 +8,9 @@ >> #include "a6xx_gpu.h" >> #include "a6xx_gmu.xml.h" >> >> +#include <linux/bitfield.h> >> #include <linux/devfreq.h> >> +#include <linux/soc/qcom/llcc-qcom.h> >> >> #define GPU_PAS_ID 13 >> >> @@ -1022,6 +1024,79 @@ static irqreturn_t a6xx_irq(struct msm_gpu >> *gpu) >> return IRQ_HANDLED; >> } >> >> +static void a6xx_llc_rmw(struct a6xx_gpu *a6xx_gpu, u32 reg, u32 >> mask, u32 or) >> +{ >> + return msm_rmw(a6xx_gpu->llc_mmio + (reg << 2), mask, or); >> +} >> + >> +static void a6xx_llc_write(struct a6xx_gpu *a6xx_gpu, u32 reg, u32 >> value) >> +{ >> + return msm_writel(value, a6xx_gpu->llc_mmio + (reg << 2)); >> +} >> + >> +static void a6xx_llc_deactivate(struct a6xx_gpu *a6xx_gpu) >> +{ >> + llcc_slice_deactivate(a6xx_gpu->llc_slice); >> + llcc_slice_deactivate(a6xx_gpu->htw_llc_slice); >> +} >> + >> +static void a6xx_llc_activate(struct a6xx_gpu *a6xx_gpu) >> +{ >> + u32 cntl1_regval = 0; >> + >> + if (IS_ERR(a6xx_gpu->llc_mmio)) >> + return; >> + >> + if (!llcc_slice_activate(a6xx_gpu->llc_slice)) { >> + u32 gpu_scid = llcc_get_slice_id(a6xx_gpu->llc_slice); >> + >> + gpu_scid &= 0x1f; >> + cntl1_regval = (gpu_scid << 0) | (gpu_scid << 5) | (gpu_scid << 10) >> | >> + (gpu_scid << 15) | (gpu_scid << 20); >> + } >> + >> + if (!llcc_slice_activate(a6xx_gpu->htw_llc_slice)) { >> + u32 gpuhtw_scid = llcc_get_slice_id(a6xx_gpu->htw_llc_slice); >> + >> + gpuhtw_scid &= 0x1f; >> + cntl1_regval |= FIELD_PREP(GENMASK(29, 25), gpuhtw_scid); >> + } >> + >> + if (cntl1_regval) { >> + /* >> + * Program the slice IDs for the various GPU blocks and GPU MMU >> + * pagetables >> + */ >> + a6xx_llc_write(a6xx_gpu, REG_A6XX_CX_MISC_SYSTEM_CACHE_CNTL_1, >> cntl1_regval); >> + >> + /* >> + * Program cacheability overrides to not allocate cache lines on >> + * a write miss >> + */ >> + a6xx_llc_rmw(a6xx_gpu, REG_A6XX_CX_MISC_SYSTEM_CACHE_CNTL_0, 0xF, >> 0x03); >> + } >> +} > > This code has been around long enough that it pre-dates a650. On a650 > and other > MMU-500 targets the htw_llc is configured by the firmware and the > llc_slice is > configured in a different register. > > I don't think we need to pause everything and add support for the > MMU-500 path, > but we do need a way to disallow LLCC on affected targets until such > time that > we can get it fixed up. >
Thanks for taking a close look, does something like below look ok or something else is needed here?
+ /* Till the time we get in LLCC support for A650 */ + if (!(info && info->revn == 650)) + a6xx_llc_slices_init(pdev, a6xx_gpu);
Thanks, Sai
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