Re: [PATCH] nvmem: mtk-efuse: Support postprocessing for GPU speed binning data

[Srinivas Kandagatla <srinivas.kandagatla@linaro.org>]

On 21/03/2023 14:33, AngeloGioacchino Del Regno wrote:
> On some MediaTek SoCs GPU speed binning data is available for read
> in the SoC's eFuse array but it has a format that is incompatible
> with what the OPP API expects, as we read a number from 0 to 7 but
> opp-supported-hw is expecting a bitmask to enable an OPP entry:
> being what we read limited to 0-7, it's straightforward to simply
> convert the value to BIT(value) as a post-processing action.
> 
> So, introduce post-processing support and enable it by evaluating
> the newly introduced platform data's `uses_post_processing` member,
> currently enabled only for MT8186.
> 
> Signed-off-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> ---

Applied thanks,

--srini
>   drivers/nvmem/mtk-efuse.c | 53 +++++++++++++++++++++++++++++++++++++--
>   1 file changed, 51 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
> index a08e0aedd21c..b36cd0dcc8c7 100644
> --- a/drivers/nvmem/mtk-efuse.c
> +++ b/drivers/nvmem/mtk-efuse.c
> @@ -10,6 +10,11 @@
>   #include <linux/io.h>
>   #include <linux/nvmem-provider.h>
>   #include <linux/platform_device.h>
> +#include <linux/property.h>
> +
> +struct mtk_efuse_pdata {
> +	bool uses_post_processing;
> +};
>   
>   struct mtk_efuse_priv {
>   	void __iomem *base;
> @@ -29,6 +34,37 @@ static int mtk_reg_read(void *context,
>   	return 0;
>   }
>   
> +static int mtk_efuse_gpu_speedbin_pp(void *context, const char *id, int index,
> +				     unsigned int offset, void *data, size_t bytes)
> +{
> +	u8 *val = data;
> +
> +	if (val[0] < 8)
> +		val[0] = BIT(val[0]);
> +
> +	return 0;
> +}
> +
> +static void mtk_efuse_fixup_cell_info(struct nvmem_device *nvmem,
> +				      struct nvmem_layout *layout,
> +				      struct nvmem_cell_info *cell)
> +{
> +	size_t sz = strlen(cell->name);
> +
> +	/*
> +	 * On some SoCs, the GPU speedbin is not read as bitmask but as
> +	 * a number with range [0-7] (max 3 bits): post process to use
> +	 * it in OPP tables to describe supported-hw.
> +	 */
> +	if (cell->nbits <= 3 &&
> +	    strncmp(cell->name, "gpu-speedbin", min(sz, strlen("gpu-speedbin"))) == 0)
> +		cell->read_post_process = mtk_efuse_gpu_speedbin_pp;
> +}
> +
> +static struct nvmem_layout mtk_efuse_layout = {
> +	.fixup_cell_info = mtk_efuse_fixup_cell_info,
> +};
> +
>   static int mtk_efuse_probe(struct platform_device *pdev)
>   {
>   	struct device *dev = &pdev->dev;
> @@ -36,6 +72,7 @@ static int mtk_efuse_probe(struct platform_device *pdev)
>   	struct nvmem_device *nvmem;
>   	struct nvmem_config econfig = {};
>   	struct mtk_efuse_priv *priv;
> +	const struct mtk_efuse_pdata *pdata;
>   
>   	priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
>   	if (!priv)
> @@ -45,20 +82,32 @@ static int mtk_efuse_probe(struct platform_device *pdev)
>   	if (IS_ERR(priv->base))
>   		return PTR_ERR(priv->base);
>   
> +	pdata = device_get_match_data(dev);
>   	econfig.stride = 1;
>   	econfig.word_size = 1;
>   	econfig.reg_read = mtk_reg_read;
>   	econfig.size = resource_size(res);
>   	econfig.priv = priv;
>   	econfig.dev = dev;
> +	if (pdata->uses_post_processing)
> +		econfig.layout = &mtk_efuse_layout;
>   	nvmem = devm_nvmem_register(dev, &econfig);
>   
>   	return PTR_ERR_OR_ZERO(nvmem);
>   }
>   
> +static const struct mtk_efuse_pdata mtk_mt8186_efuse_pdata = {
> +	.uses_post_processing = true,
> +};
> +
> +static const struct mtk_efuse_pdata mtk_efuse_pdata = {
> +	.uses_post_processing = false,
> +};
> +
>   static const struct of_device_id mtk_efuse_of_match[] = {
> -	{ .compatible = "mediatek,mt8173-efuse",},
> -	{ .compatible = "mediatek,efuse",},
> +	{ .compatible = "mediatek,mt8173-efuse", .data = &mtk_efuse_pdata },
> +	{ .compatible = "mediatek,mt8186-efuse", .data = &mtk_mt8186_efuse_pdata },
> +	{ .compatible = "mediatek,efuse", .data = &mtk_efuse_pdata },
>   	{/* sentinel */},
>   };
>   MODULE_DEVICE_TABLE(of, mtk_efuse_of_match);