Re: [PATCH v5 1/5] drm/msm/adreno: Implement SMEM-based speed bin

[Akhil P Oommen]

On Tue, Jul 09, 2024 at 12:45:29PM +0200, Konrad Dybcio wrote:
> On recent (SM8550+) Snapdragon platforms, the GPU speed bin data is
> abstracted through SMEM, instead of being directly available in a fuse.
> 
> Add support for SMEM-based speed binning, which includes getting
> "feature code" and "product code" from said source and parsing them
> to form something that lets us match OPPs against.
> 
> Due to the product code being ignored in the context of Adreno on
> production parts (as of SM8650), hardcode it to SOCINFO_PC_UNKNOWN.
> 
> Signed-off-by: Konrad Dybcio <konrad.dybcio@xxxxxxxxxx>
> ---
>  drivers/gpu/drm/msm/adreno/a6xx_gpu.c      | 14 +++++-----
>  drivers/gpu/drm/msm/adreno/adreno_device.c |  2 ++
>  drivers/gpu/drm/msm/adreno/adreno_gpu.c    | 42 +++++++++++++++++++++++++++---
>  drivers/gpu/drm/msm/adreno/adreno_gpu.h    |  7 ++++-
>  4 files changed, 54 insertions(+), 11 deletions(-)
> 
> diff --git a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> index bcaec86ac67a..0d8682c28ba4 100644
> --- a/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/a6xx_gpu.c
> @@ -2117,18 +2117,20 @@ static u32 fuse_to_supp_hw(const struct adreno_info *info, u32 fuse)
>  	return UINT_MAX;
>  }
>  
> -static int a6xx_set_supported_hw(struct device *dev, const struct adreno_info *info)
> +static int a6xx_set_supported_hw(struct adreno_gpu *adreno_gpu,
> +				 struct device *dev,
> +				 const struct adreno_info *info)
>  {
>  	u32 supp_hw;
>  	u32 speedbin;
>  	int ret;
>  
> -	ret = adreno_read_speedbin(dev, &speedbin);
> +	ret = adreno_read_speedbin(adreno_gpu, dev, &speedbin);
>  	/*
> -	 * -ENOENT means that the platform doesn't support speedbin which is
> -	 * fine
> +	 * -ENOENT/EOPNOTSUPP means that the platform doesn't support speedbin
> +	 * which is fine
>  	 */
> -	if (ret == -ENOENT) {
> +	if (ret == -ENOENT || ret == -EOPNOTSUPP) {
>  		return 0;
>  	} else if (ret) {
>  		dev_err_probe(dev, ret,
> @@ -2283,7 +2285,7 @@ struct msm_gpu *a6xx_gpu_init(struct drm_device *dev)
>  
>  	a6xx_llc_slices_init(pdev, a6xx_gpu, is_a7xx);
>  
> -	ret = a6xx_set_supported_hw(&pdev->dev, config->info);
> +	ret = a6xx_set_supported_hw(adreno_gpu, &pdev->dev, config->info);
>  	if (ret) {
>  		a6xx_llc_slices_destroy(a6xx_gpu);
>  		kfree(a6xx_gpu);
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_device.c b/drivers/gpu/drm/msm/adreno/adreno_device.c
> index cfc74a9e2646..0842ea76e616 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_device.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_device.c
> @@ -6,6 +6,8 @@
>   * Copyright (c) 2014,2017 The Linux Foundation. All rights reserved.
>   */
>  
> +#include <linux/soc/qcom/socinfo.h>
> +
>  #include "adreno_gpu.h"
>  
>  bool hang_debug = false;
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.c b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> index 1c6626747b98..cf6652c4439d 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.c
> @@ -21,6 +21,9 @@
>  #include "msm_gem.h"
>  #include "msm_mmu.h"
>  
> +#include <linux/soc/qcom/smem.h>
> +#include <linux/soc/qcom/socinfo.h>
> +
>  static u64 address_space_size = 0;
>  MODULE_PARM_DESC(address_space_size, "Override for size of processes private GPU address space");
>  module_param(address_space_size, ullong, 0600);
> @@ -1061,9 +1064,40 @@ void adreno_gpu_ocmem_cleanup(struct adreno_ocmem *adreno_ocmem)
>  			   adreno_ocmem->hdl);
>  }
>  
> -int adreno_read_speedbin(struct device *dev, u32 *speedbin)
> +int adreno_read_speedbin(struct adreno_gpu *adreno_gpu,
> +			 struct device *dev, u32 *fuse)
>  {
> -	return nvmem_cell_read_variable_le_u32(dev, "speed_bin", speedbin);
> +	int ret;
> +
> +	/*
> +	 * Try reading the speedbin via a nvmem cell first
> +	 * -ENOENT means "no nvmem-cells" and essentially means "old DT" or
> +	 * "nvmem fuse is irrelevant", simply assume it's fine.
> +	 */
> +	ret = nvmem_cell_read_variable_le_u32(dev, "speed_bin", fuse);
> +	if (!ret)
> +		return 0;
> +	else if (ret != -ENOENT)
> +		return dev_err_probe(dev, ret, "Couldn't read the speed bin fuse value\n");
> +
> +#ifdef CONFIG_QCOM_SMEM
> +	u32 fcode;
> +
> +	/*
> +	 * Only check the feature code - the product code only matters for
> +	 * proto SoCs unavailable outside Qualcomm labs, as far as GPU bin
> +	 * matching is concerned.
> +	 *
> +	 * Ignore EOPNOTSUPP, as not all SoCs expose this info through SMEM.
> +	 */
> +	ret = qcom_smem_get_feature_code(&fcode);
> +	if (!ret)
> +		*fuse = ADRENO_SKU_ID(fcode);
> +	else if (ret != -EOPNOTSUPP)
> +		return dev_err_probe(dev, ret, "Couldn't get feature code from SMEM\n");
> +#endif
> +
> +	return ret;
>  }
>  
>  int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
> @@ -1102,9 +1136,9 @@ int adreno_gpu_init(struct drm_device *drm, struct platform_device *pdev,
>  			devm_pm_opp_set_clkname(dev, "core");
>  	}
>  
> -	if (adreno_read_speedbin(dev, &speedbin) || !speedbin)
> +	if (adreno_read_speedbin(adreno_gpu, dev, &speedbin) || !speedbin)
>  		speedbin = 0xffff;
> -	adreno_gpu->speedbin = (uint16_t) (0xffff & speedbin);
> +	adreno_gpu->speedbin = speedbin;

There are some chipsets which uses both Speedbin and Socinfo data for
SKU detection [1]. We don't need to worry about that logic for now. But
I am worried about mixing Speedbin and SKU_ID in the UABI with this patch.
It will be difficult when we have to expose both to userspace.

I think we can use a separate bitfield to expose FCODE/PCODE. Currently,
the lower 32 bit is reserved for chipid and 33-48 is reserved for speedbin,
so I think we can use the rest of the 16 bits for SKU_ID. And within that
16bits, 12 bits should be sufficient for FCODE and the rest 8 bits
reserved for future PCODE.

[1] https://git.codelinaro.org/clo/la/platform/vendor/qcom/opensource/graphics-kernel/-/commit/ab8015dec341d85cd1c97aa7eb5a903527496102

-Akhil


>  
>  	gpu_name = devm_kasprintf(dev, GFP_KERNEL, "%"ADRENO_CHIPID_FMT,
>  			ADRENO_CHIPID_ARGS(config->chip_id));
> diff --git a/drivers/gpu/drm/msm/adreno/adreno_gpu.h b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> index 1ab523a163a0..0d629343ebb4 100644
> --- a/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> +++ b/drivers/gpu/drm/msm/adreno/adreno_gpu.h
> @@ -79,6 +79,10 @@ struct adreno_reglist {
>  
>  struct adreno_speedbin {
>  	uint16_t fuse;
> +/* As of SM8650, PCODE on production SoCs is meaningless wrt the GPU bin */
> +#define ADRENO_SKU_ID_FCODE		GENMASK(15, 0)
> +#define ADRENO_SKU_ID(fcode)	(fcode)
> +
>  	uint16_t speedbin;
>  };
>  
> @@ -555,7 +559,8 @@ int adreno_fault_handler(struct msm_gpu *gpu, unsigned long iova, int flags,
>  			 struct adreno_smmu_fault_info *info, const char *block,
>  			 u32 scratch[4]);
>  
> -int adreno_read_speedbin(struct device *dev, u32 *speedbin);
> +int adreno_read_speedbin(struct adreno_gpu *adreno_gpu,
> +			 struct device *dev, u32 *speedbin);
>  
>  /*
>   * For a5xx and a6xx targets load the zap shader that is used to pull the GPU
> 
> -- 
> 2.45.2
>