[PATCHv5,4/6] drm/msm/a6xx: Add support for using system cache(LLC)

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(+)

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.

Jordan

> +
> +static void a6xx_llc_slices_destroy(struct a6xx_gpu *a6xx_gpu)
> +{
> +	llcc_slice_putd(a6xx_gpu->llc_slice);
> +	llcc_slice_putd(a6xx_gpu->htw_llc_slice);
> +}
> +
> +static void a6xx_llc_slices_init(struct platform_device *pdev,
> +		struct a6xx_gpu *a6xx_gpu)
> +{
> +	a6xx_gpu->llc_mmio = msm_ioremap(pdev, "cx_mem", "gpu_cx");
> +	if (IS_ERR(a6xx_gpu->llc_mmio))
> +		return;
> +
> +	a6xx_gpu->llc_slice = llcc_slice_getd(LLCC_GPU);
> +	a6xx_gpu->htw_llc_slice = llcc_slice_getd(LLCC_GPUHTW);
> +
> +	if (IS_ERR(a6xx_gpu->llc_slice) && IS_ERR(a6xx_gpu->htw_llc_slice))
> +		a6xx_gpu->llc_mmio = ERR_PTR(-EINVAL);
> +}
> +
>  static int a6xx_pm_resume(struct msm_gpu *gpu)
>  {
>  	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> @@ -1038,6 +1113,8 @@ static int a6xx_pm_resume(struct msm_gpu *gpu)
>  
>  	msm_gpu_resume_devfreq(gpu);
>  
> +	a6xx_llc_activate(a6xx_gpu);
> +
>  	return 0;
>  }
>  
> @@ -1048,6 +1125,8 @@ static int a6xx_pm_suspend(struct msm_gpu *gpu)
>  
>  	trace_msm_gpu_suspend(0);
>  
> +	a6xx_llc_deactivate(a6xx_gpu);
> +
>  	devfreq_suspend_device(gpu->devfreq.devfreq);
>  
>  	return a6xx_gmu_stop(a6xx_gpu);
> @@ -1091,6 +1170,8 @@ static void a6xx_destroy(struct msm_gpu *gpu)
>  		drm_gem_object_put(a6xx_gpu->shadow_bo);
>  	}
>  
> +	a6xx_llc_slices_destroy(a6xx_gpu);
> +
>  	a6xx_gmu_remove(a6xx_gpu);
>  
>  	adreno_gpu_cleanup(adreno_gpu);
> @@ -1209,6 +1290,8 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
>  	if (info && info->revn == 650)
>  		adreno_gpu->base.hw_apriv = true;
>  
> +	a6xx_llc_slices_init(pdev, a6xx_gpu);
> +
>  	ret = adreno_gpu_init(dev, pdev, adreno_gpu, &funcs, 1);
>  	if (ret) {
>  		a6xx_destroy(&(a6xx_gpu->base.base));
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> index 3eeebf6a754b..9e6079af679c 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.h
> @@ -28,6 +28,10 @@ struct a6xx_gpu {
>  	uint32_t *shadow;
>  
>  	bool has_whereami;
> +
> +	void __iomem *llc_mmio;
> +	void *llc_slice;
> +	void *htw_llc_slice;
>  };
>  
>  #define to_a6xx_gpu(x) container_of(x, struct a6xx_gpu, base)
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index fd8f491f2e48..86c4fe667225 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -16,6 +16,7 @@
>  #include <linux/soc/qcom/mdt_loader.h>
>  #include <soc/qcom/ocmem.h>
>  #include "adreno_gpu.h"
> +#include "a6xx_gpu.h"
>  #include "msm_gem.h"
>  #include "msm_mmu.h"
>  
> @@ -189,6 +190,8 @@ struct msm_gem_address_space *
>  adreno_iommu_create_address_space(struct msm_gpu *gpu,
>  		struct platform_device *pdev)
>  {
> +	struct adreno_gpu *adreno_gpu = to_adreno_gpu(gpu);
> +	struct a6xx_gpu *a6xx_gpu = to_a6xx_gpu(adreno_gpu);
>  	struct iommu_domain *iommu;
>  	struct msm_mmu *mmu;
>  	struct msm_gem_address_space *aspace;
> @@ -198,7 +201,21 @@ adreno_iommu_create_address_space(struct msm_gpu *gpu,
>  	if (!iommu)
>  		return NULL;
>  
> +	/*
> +	 * This allows GPU to set the bus attributes required to use system
> +	 * cache on behalf of the iommu page table walker.
> +	 */
> +	if (!IS_ERR(a6xx_gpu->htw_llc_slice)) {
> +		int gpu_htw_llc = 1;
> +
> +		iommu_domain_set_attr(iommu, DOMAIN_ATTR_SYS_CACHE, &gpu_htw_llc);
> +	}
> +
>  	mmu = msm_iommu_new(&pdev->dev, iommu);
> +	if (IS_ERR(mmu)) {
> +		iommu_domain_free(iommu);
> +		return ERR_CAST(mmu);
> +	}
>  
>  	/*
>  	 * Use the aperture start or SZ_16M, whichever is greater. This will
> -- 
> QUALCOMM INDIA, on behalf of Qualcomm Innovation Center, Inc. is a member
> of Code Aurora Forum, hosted by The Linux Foundation
>

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

On Mon, Sep 28, 2020 at 05:56:55PM +0530, Sai Prakash Ranjan wrote:
> 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);

It doesn't look like Rob picked this up for 5.10, so we have some time to do it
right.  Would you like me to give you an add-on patch for mmu-500 targets?

Jordan

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

On 2020-09-28 21:41, Jordan Crouse wrote:
> On Mon, Sep 28, 2020 at 05:56:55PM +0530, Sai Prakash Ranjan wrote:
>> 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);
> 
> It doesn't look like Rob picked this up for 5.10, so we have some time 
> to do it
> right.  Would you like me to give you an add-on patch for mmu-500 
> targets?
> 

Yes that will be great.

Thanks,
Sai