[PATCHv7 5/7] drm/msm/a6xx: Add support for using system cache on MMU500 based targets

From: Sai Prakash Ranjan
Date: Fri Oct 30 2020 - 05:24:14 EST


From: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>

This is an extension to the series [1] to enable the System Cache (LLC) for
Adreno a6xx targets.

GPU targets with an MMU-500 attached have a slightly different process for
enabling system cache. Use the compatible string on the IOMMU phandle
to see if an MMU-500 is attached and modify the programming sequence
accordingly.

[1] https://patchwork.freedesktop.org/series/83037/

Signed-off-by: Jordan Crouse <jcrouse@xxxxxxxxxxxxxx>
Signed-off-by: Sai Prakash Ranjan <saiprakash.ranjan@xxxxxxxxxxxxxx>
---
drivers/gpu/drm/msm/adreno/a6xx_gpu.c | 46 +++++++++++++++++++++------
drivers/gpu/drm/msm/adreno/a6xx_gpu.h | 1 +
2 files changed, 37 insertions(+), 10 deletions(-)

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
index 95c98c642876..3f8b92da8cba 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
@@ -1042,6 +1042,8 @@ static void a6xx_llc_deactivate(struct a6xx_gpu *a6xx_gpu)

static void a6xx_llc_activate(struct a6xx_gpu *a6xx_gpu)
{
+ struct adreno_gpu *adreno_gpu = &a6xx_gpu->base;
+ struct msm_gpu *gpu = &adreno_gpu->base;
u32 cntl1_regval = 0;

if (IS_ERR(a6xx_gpu->llc_mmio))
@@ -1055,11 +1057,17 @@ static void a6xx_llc_activate(struct a6xx_gpu *a6xx_gpu)
(gpu_scid << 15) | (gpu_scid << 20);
}

+ /*
+ * For targets with a MMU500, activate the slice but don't program the
+ * register. The XBL will take care of that.
+ */
if (!llcc_slice_activate(a6xx_gpu->htw_llc_slice)) {
- u32 gpuhtw_scid = llcc_get_slice_id(a6xx_gpu->htw_llc_slice);
+ if (!a6xx_gpu->have_mmu500) {
+ u32 gpuhtw_scid = llcc_get_slice_id(a6xx_gpu->htw_llc_slice);

- gpuhtw_scid &= 0x1f;
- cntl1_regval |= FIELD_PREP(GENMASK(29, 25), gpuhtw_scid);
+ gpuhtw_scid &= 0x1f;
+ cntl1_regval |= FIELD_PREP(GENMASK(29, 25), gpuhtw_scid);
+ }
}

if (cntl1_regval) {
@@ -1067,13 +1075,20 @@ static void a6xx_llc_activate(struct a6xx_gpu *a6xx_gpu)
* 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);
+ if (a6xx_gpu->have_mmu500)
+ gpu_rmw(gpu, REG_A6XX_GBIF_SCACHE_CNTL1, GENMASK(24, 0),
+ cntl1_regval);
+ else {
+ 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);
+ }
}
}

@@ -1086,10 +1101,21 @@ static void a6xx_llc_slices_destroy(struct a6xx_gpu *a6xx_gpu)
static void a6xx_llc_slices_init(struct platform_device *pdev,
struct a6xx_gpu *a6xx_gpu)
{
+ struct device_node *phandle;
+
a6xx_gpu->llc_mmio = msm_ioremap(pdev, "cx_mem", "gpu_cx");
if (IS_ERR(a6xx_gpu->llc_mmio))
return;

+ /*
+ * There is a different programming path for targets with an mmu500
+ * attached, so detect if that is the case
+ */
+ phandle = of_parse_phandle(pdev->dev.of_node, "iommus", 0);
+ a6xx_gpu->have_mmu500 = (phandle &&
+ of_device_is_compatible(phandle, "arm,mmu-500"));
+ of_node_put(phandle);
+
a6xx_gpu->llc_slice = llcc_slice_getd(LLCC_GPU);
a6xx_gpu->htw_llc_slice = llcc_slice_getd(LLCC_GPUHTW);

diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
index 9e6079af679c..e793d329e77b 100644
--- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
+++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
@@ -32,6 +32,7 @@ struct a6xx_gpu {
void __iomem *llc_mmio;
void *llc_slice;
void *htw_llc_slice;
+ bool have_mmu500;
};

#define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
--
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