[PATCH 27/40] nvmem: mtk-efuse: Support postprocessing for GPU speed binning data

From: Srinivas Kandagatla
Date: Tue Apr 04 2023 - 13:24:13 EST


From: AngeloGioacchino Del Regno <angelogioacchino.delregno@xxxxxxxxxxxxx>

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@xxxxxxxxxxxxx>
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@xxxxxxxxxx>
---
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);
--
2.25.1