[PATCH V3] nvmem: add explicit config option to read OF fixed cells
Srinivas Kandagatla
srinivas.kandagatla at linaro.org
Fri Mar 10 01:22:19 PST 2023
On 09/03/2023 11:20, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal at milecki.pl>
>
> NVMEM subsystem looks for fixed NVMEM cells (specified in DT) by
> default. This behaviour was totally safe in early days before adding
> support for dynamic cells and with simple DT syntax.
>
> With every new supported NVMEM device with dynamic cells the current
> behaviour becomes non-optimal:
> 1. It results in unneeded iterating over DT nodes
> 2. It may result in false discovery of cells (in case DT subnodes
> contain "reg" property)
>
Am really not sure what is going on here,
I did raise some issues with this overall approch to start with at [1]
none of which are discussed and now I see v3 :-)
[1]
https://lore.kernel.org/lkml/20230309094010.1051573-1-michael@walle.cc/T/#m7706b640979aabf251436e017b8189413661a53a
--srini
> This behaviour has actually caused a problem already with the MTD
> subsystem and required a fix. MTD subpartitions were incorrectly treated
> (falsely discovered) as NVMEM cells.
>
> Also with the support for NVMEM layouts we may & should have *new*
> bindings allow fixed NVMEM cells only in the "nvmem-layout" subnode. It
> means no *new* driver should require NVMEM core support for fixed cells
> defined in the **device** node.
>
> Obviously existing bindings must be supported and old drivers must
> support old DT syntax.
>
> The best approach seems to be making NVMEM core looking for fixed DT
> cells in **device** node an opt-in feature. It's a feature that over
> time should get deprecated in a favor of using "nvmem-layouts" also for
> fixed NVMEM cells.
>
> Solve this by modifying drivers for those bindings that support
> specifying fixed NVMEM cells in DT node of **NVMEM device**. Those
> drivers were picked by reviewing all supported NVMEM bindings. Make
> those drivers explicitly tell NVMEM subsystem to read cells from DT node
> of **NVMEM device**.
>
> It wasn't clear (to me) if rtc and w1 code actually uses fixed cells. I
> enabled them to don't risk any breakage.
>
> The whole change is not a huge game changer. It makes code slightly more
> optimal (in case you care), a bit less error prone and maybe / hopefully
> NVMEM code parsing code easier to understand.
>
> Signed-off-by: Rafał Miłecki <rafal at milecki.pl>
> [for meson-{efuse,mx-efuse}.c]
> Acked-by: Martin Blumenstingl <martin.blumenstingl at googlemail.com>
> [for mtk-efuse.c, nvmem/core.c, nvmem-provider.h]
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
> [MT8192, MT8195 Chromebooks]
> Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno at collabora.com>
> [for microchip-otpc.c]
> Reviewed-by: Claudiu Beznea <claudiu.beznea at microchip.com>
> [SAMA7G5-EK]
> Tested-by: Claudiu Beznea <claudiu.beznea at microchip.com>
> ---
> V2: Fix stm32-romem.c typo breaking its compilation
> Pick Martin's Acked-by
> Add paragraph about layouts deprecating use_fixed_of_cells
> V3: Update commit description:
> 1. Make it clear we're NOT dropping fixed cells support
> 2. Use nicer words (s/made sense/was totally safe/)
> 3. Explain fixed cells layout thing
> 4. Add paragraph with purpose of this commit
> ---
> drivers/mtd/mtdcore.c | 2 ++
> drivers/nvmem/apple-efuses.c | 1 +
> drivers/nvmem/core.c | 8 +++++---
> drivers/nvmem/imx-ocotp-scu.c | 1 +
> drivers/nvmem/imx-ocotp.c | 1 +
> drivers/nvmem/meson-efuse.c | 1 +
> drivers/nvmem/meson-mx-efuse.c | 1 +
> drivers/nvmem/microchip-otpc.c | 1 +
> drivers/nvmem/mtk-efuse.c | 1 +
> drivers/nvmem/qcom-spmi-sdam.c | 1 +
> drivers/nvmem/qfprom.c | 1 +
> drivers/nvmem/rave-sp-eeprom.c | 1 +
> drivers/nvmem/rockchip-efuse.c | 1 +
> drivers/nvmem/sc27xx-efuse.c | 1 +
> drivers/nvmem/sprd-efuse.c | 1 +
> drivers/nvmem/stm32-romem.c | 1 +
> drivers/nvmem/sunplus-ocotp.c | 1 +
> drivers/nvmem/sunxi_sid.c | 1 +
> drivers/nvmem/uniphier-efuse.c | 1 +
> drivers/nvmem/zynqmp_nvmem.c | 1 +
> drivers/rtc/nvmem.c | 1 +
> drivers/w1/slaves/w1_ds250x.c | 1 +
> include/linux/nvmem-provider.h | 2 ++
> 23 files changed, 29 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/mtd/mtdcore.c b/drivers/mtd/mtdcore.c
> index 0feacb9fbdac..1bb479c0f758 100644
> --- a/drivers/mtd/mtdcore.c
> +++ b/drivers/mtd/mtdcore.c
> @@ -523,6 +523,7 @@ static int mtd_nvmem_add(struct mtd_info *mtd)
> config.dev = &mtd->dev;
> config.name = dev_name(&mtd->dev);
> config.owner = THIS_MODULE;
> + config.use_fixed_of_cells = of_device_is_compatible(node, "nvmem-cells");
> config.reg_read = mtd_nvmem_reg_read;
> config.size = mtd->size;
> config.word_size = 1;
> @@ -891,6 +892,7 @@ static struct nvmem_device *mtd_otp_nvmem_register(struct mtd_info *mtd,
> config.name = kasprintf(GFP_KERNEL, "%s-%s", dev_name(&mtd->dev), compatible);
> config.id = NVMEM_DEVID_NONE;
> config.owner = THIS_MODULE;
> + config.use_fixed_of_cells = true;
> config.type = NVMEM_TYPE_OTP;
> config.root_only = true;
> config.ignore_wp = true;
> diff --git a/drivers/nvmem/apple-efuses.c b/drivers/nvmem/apple-efuses.c
> index 9b7c87102104..0119bac43b2c 100644
> --- a/drivers/nvmem/apple-efuses.c
> +++ b/drivers/nvmem/apple-efuses.c
> @@ -36,6 +36,7 @@ static int apple_efuses_probe(struct platform_device *pdev)
> struct resource *res;
> struct nvmem_config config = {
> .dev = &pdev->dev,
> + .use_fixed_of_cells = true,
> .read_only = true,
> .reg_read = apple_efuses_read,
> .stride = sizeof(u32),
> diff --git a/drivers/nvmem/core.c b/drivers/nvmem/core.c
> index 174ef3574e07..6783cd8478d7 100644
> --- a/drivers/nvmem/core.c
> +++ b/drivers/nvmem/core.c
> @@ -844,9 +844,11 @@ struct nvmem_device *nvmem_register(const struct nvmem_config *config)
> if (rval)
> goto err_remove_cells;
>
> - rval = nvmem_add_cells_from_of(nvmem);
> - if (rval)
> - goto err_remove_cells;
> + if (config->use_fixed_of_cells) {
> + rval = nvmem_add_cells_from_of(nvmem);
> + if (rval)
> + goto err_remove_cells;
> + }
>
> dev_dbg(&nvmem->dev, "Registering nvmem device %s\n", config->name);
>
> diff --git a/drivers/nvmem/imx-ocotp-scu.c b/drivers/nvmem/imx-ocotp-scu.c
> index 399e1eb8b4c1..ec5cce7c6697 100644
> --- a/drivers/nvmem/imx-ocotp-scu.c
> +++ b/drivers/nvmem/imx-ocotp-scu.c
> @@ -220,6 +220,7 @@ static int imx_scu_ocotp_write(void *context, unsigned int offset,
>
> static struct nvmem_config imx_scu_ocotp_nvmem_config = {
> .name = "imx-scu-ocotp",
> + .use_fixed_of_cells = true,
> .read_only = false,
> .word_size = 4,
> .stride = 1,
> diff --git a/drivers/nvmem/imx-ocotp.c b/drivers/nvmem/imx-ocotp.c
> index e9b52ecb3f72..e37a82f98ba6 100644
> --- a/drivers/nvmem/imx-ocotp.c
> +++ b/drivers/nvmem/imx-ocotp.c
> @@ -616,6 +616,7 @@ static int imx_ocotp_probe(struct platform_device *pdev)
> return PTR_ERR(priv->clk);
>
> priv->params = of_device_get_match_data(&pdev->dev);
> + imx_ocotp_nvmem_config.use_fixed_of_cells = true;
> imx_ocotp_nvmem_config.size = 4 * priv->params->nregs;
> imx_ocotp_nvmem_config.dev = dev;
> imx_ocotp_nvmem_config.priv = priv;
> diff --git a/drivers/nvmem/meson-efuse.c b/drivers/nvmem/meson-efuse.c
> index d6b533497ce1..657e171d5af3 100644
> --- a/drivers/nvmem/meson-efuse.c
> +++ b/drivers/nvmem/meson-efuse.c
> @@ -93,6 +93,7 @@ static int meson_efuse_probe(struct platform_device *pdev)
>
> econfig->dev = dev;
> econfig->name = dev_name(dev);
> + econfig->use_fixed_of_cells = true;
> econfig->stride = 1;
> econfig->word_size = 1;
> econfig->reg_read = meson_efuse_read;
> diff --git a/drivers/nvmem/meson-mx-efuse.c b/drivers/nvmem/meson-mx-efuse.c
> index 13eb14316f46..7cc51391ec9c 100644
> --- a/drivers/nvmem/meson-mx-efuse.c
> +++ b/drivers/nvmem/meson-mx-efuse.c
> @@ -213,6 +213,7 @@ static int meson_mx_efuse_probe(struct platform_device *pdev)
> efuse->config.owner = THIS_MODULE;
> efuse->config.dev = &pdev->dev;
> efuse->config.priv = efuse;
> + efuse->config.use_fixed_of_cells = true;
> efuse->config.stride = drvdata->word_size;
> efuse->config.word_size = drvdata->word_size;
> efuse->config.size = SZ_512;
> diff --git a/drivers/nvmem/microchip-otpc.c b/drivers/nvmem/microchip-otpc.c
> index 436e0dc4f337..fb920fd7a8fc 100644
> --- a/drivers/nvmem/microchip-otpc.c
> +++ b/drivers/nvmem/microchip-otpc.c
> @@ -261,6 +261,7 @@ static int mchp_otpc_probe(struct platform_device *pdev)
> return ret;
>
> mchp_nvmem_config.dev = otpc->dev;
> + mchp_nvmem_config.use_fixed_of_cells = true;
> mchp_nvmem_config.size = size;
> mchp_nvmem_config.priv = otpc;
> nvmem = devm_nvmem_register(&pdev->dev, &mchp_nvmem_config);
> diff --git a/drivers/nvmem/mtk-efuse.c b/drivers/nvmem/mtk-efuse.c
> index a08e0aedd21c..1947337a121f 100644
> --- a/drivers/nvmem/mtk-efuse.c
> +++ b/drivers/nvmem/mtk-efuse.c
> @@ -45,6 +45,7 @@ static int mtk_efuse_probe(struct platform_device *pdev)
> if (IS_ERR(priv->base))
> return PTR_ERR(priv->base);
>
> + econfig.use_fixed_of_cells = true;
> econfig.stride = 1;
> econfig.word_size = 1;
> econfig.reg_read = mtk_reg_read;
> diff --git a/drivers/nvmem/qcom-spmi-sdam.c b/drivers/nvmem/qcom-spmi-sdam.c
> index f822790db49e..b547def94b5b 100644
> --- a/drivers/nvmem/qcom-spmi-sdam.c
> +++ b/drivers/nvmem/qcom-spmi-sdam.c
> @@ -142,6 +142,7 @@ static int sdam_probe(struct platform_device *pdev)
> sdam->sdam_config.name = "spmi_sdam";
> sdam->sdam_config.id = NVMEM_DEVID_AUTO;
> sdam->sdam_config.owner = THIS_MODULE;
> + sdam->sdam_config.use_fixed_of_cells = true;
> sdam->sdam_config.stride = 1;
> sdam->sdam_config.word_size = 1;
> sdam->sdam_config.reg_read = sdam_read;
> diff --git a/drivers/nvmem/qfprom.c b/drivers/nvmem/qfprom.c
> index c1e893c8a247..eb126d507561 100644
> --- a/drivers/nvmem/qfprom.c
> +++ b/drivers/nvmem/qfprom.c
> @@ -357,6 +357,7 @@ static int qfprom_probe(struct platform_device *pdev)
> {
> struct nvmem_config econfig = {
> .name = "qfprom",
> + .use_fixed_of_cells = true,
> .stride = 1,
> .word_size = 1,
> .id = NVMEM_DEVID_AUTO,
> diff --git a/drivers/nvmem/rave-sp-eeprom.c b/drivers/nvmem/rave-sp-eeprom.c
> index c456011b75e8..e9b4c7927e37 100644
> --- a/drivers/nvmem/rave-sp-eeprom.c
> +++ b/drivers/nvmem/rave-sp-eeprom.c
> @@ -328,6 +328,7 @@ static int rave_sp_eeprom_probe(struct platform_device *pdev)
> of_property_read_string(np, "zii,eeprom-name", &config.name);
> config.priv = eeprom;
> config.dev = dev;
> + config.use_fixed_of_cells = true;
> config.size = size;
> config.reg_read = rave_sp_eeprom_reg_read;
> config.reg_write = rave_sp_eeprom_reg_write;
> diff --git a/drivers/nvmem/rockchip-efuse.c b/drivers/nvmem/rockchip-efuse.c
> index e4579de5d014..211f6e7401a9 100644
> --- a/drivers/nvmem/rockchip-efuse.c
> +++ b/drivers/nvmem/rockchip-efuse.c
> @@ -205,6 +205,7 @@ static int rockchip_rk3399_efuse_read(void *context, unsigned int offset,
>
> static struct nvmem_config econfig = {
> .name = "rockchip-efuse",
> + .use_fixed_of_cells = true,
> .stride = 1,
> .word_size = 1,
> .read_only = true,
> diff --git a/drivers/nvmem/sc27xx-efuse.c b/drivers/nvmem/sc27xx-efuse.c
> index c825fc902d10..ed5cc4f3e2bc 100644
> --- a/drivers/nvmem/sc27xx-efuse.c
> +++ b/drivers/nvmem/sc27xx-efuse.c
> @@ -248,6 +248,7 @@ static int sc27xx_efuse_probe(struct platform_device *pdev)
> econfig.reg_read = sc27xx_efuse_read;
> econfig.priv = efuse;
> econfig.dev = &pdev->dev;
> + econfig.use_fixed_of_cells = true;
> nvmem = devm_nvmem_register(&pdev->dev, &econfig);
> if (IS_ERR(nvmem)) {
> dev_err(&pdev->dev, "failed to register nvmem config\n");
> diff --git a/drivers/nvmem/sprd-efuse.c b/drivers/nvmem/sprd-efuse.c
> index 4f1fcbfec394..ef3161645f60 100644
> --- a/drivers/nvmem/sprd-efuse.c
> +++ b/drivers/nvmem/sprd-efuse.c
> @@ -408,6 +408,7 @@ static int sprd_efuse_probe(struct platform_device *pdev)
> econfig.read_only = false;
> econfig.name = "sprd-efuse";
> econfig.size = efuse->data->blk_nums * SPRD_EFUSE_BLOCK_WIDTH;
> + econfig.use_fixed_of_cells = true;
> econfig.reg_read = sprd_efuse_read;
> econfig.reg_write = sprd_efuse_write;
> econfig.priv = efuse;
> diff --git a/drivers/nvmem/stm32-romem.c b/drivers/nvmem/stm32-romem.c
> index ba779e26937a..a6fc43acb797 100644
> --- a/drivers/nvmem/stm32-romem.c
> +++ b/drivers/nvmem/stm32-romem.c
> @@ -208,6 +208,7 @@ static int stm32_romem_probe(struct platform_device *pdev)
> priv->cfg.priv = priv;
> priv->cfg.owner = THIS_MODULE;
> priv->cfg.type = NVMEM_TYPE_OTP;
> + priv->cfg.use_fixed_of_cells = true;
>
> priv->lower = 0;
>
> diff --git a/drivers/nvmem/sunplus-ocotp.c b/drivers/nvmem/sunplus-ocotp.c
> index 52b928a7a6d5..57e3e0833b85 100644
> --- a/drivers/nvmem/sunplus-ocotp.c
> +++ b/drivers/nvmem/sunplus-ocotp.c
> @@ -145,6 +145,7 @@ static int sp_ocotp_read(void *priv, unsigned int offset, void *value, size_t by
>
> static struct nvmem_config sp_ocotp_nvmem_config = {
> .name = "sp-ocotp",
> + .use_fixed_of_cells = true,
> .read_only = true,
> .word_size = 1,
> .size = QAC628_OTP_SIZE,
> diff --git a/drivers/nvmem/sunxi_sid.c b/drivers/nvmem/sunxi_sid.c
> index a970f1741cc6..6ab7aa3724a0 100644
> --- a/drivers/nvmem/sunxi_sid.c
> +++ b/drivers/nvmem/sunxi_sid.c
> @@ -156,6 +156,7 @@ static int sunxi_sid_probe(struct platform_device *pdev)
> nvmem_cfg->dev = dev;
> nvmem_cfg->name = "sunxi-sid";
> nvmem_cfg->type = NVMEM_TYPE_OTP;
> + nvmem_cfg->use_fixed_of_cells = true;
> nvmem_cfg->read_only = true;
> nvmem_cfg->size = cfg->size;
> nvmem_cfg->word_size = 1;
> diff --git a/drivers/nvmem/uniphier-efuse.c b/drivers/nvmem/uniphier-efuse.c
> index aca910b3b6f8..69b9dfe6ab6e 100644
> --- a/drivers/nvmem/uniphier-efuse.c
> +++ b/drivers/nvmem/uniphier-efuse.c
> @@ -53,6 +53,7 @@ static int uniphier_efuse_probe(struct platform_device *pdev)
> econfig.size = resource_size(res);
> econfig.priv = priv;
> econfig.dev = dev;
> + econfig.use_fixed_of_cells = true;
> nvmem = devm_nvmem_register(dev, &econfig);
>
> return PTR_ERR_OR_ZERO(nvmem);
> diff --git a/drivers/nvmem/zynqmp_nvmem.c b/drivers/nvmem/zynqmp_nvmem.c
> index e28d7b133e11..d13750a4c112 100644
> --- a/drivers/nvmem/zynqmp_nvmem.c
> +++ b/drivers/nvmem/zynqmp_nvmem.c
> @@ -58,6 +58,7 @@ static int zynqmp_nvmem_probe(struct platform_device *pdev)
>
> priv->dev = dev;
> econfig.dev = dev;
> + econfig.use_fixed_of_cells = true;
> econfig.reg_read = zynqmp_nvmem_read;
> econfig.priv = priv;
>
> diff --git a/drivers/rtc/nvmem.c b/drivers/rtc/nvmem.c
> index 07ede21cee34..5cc039d92257 100644
> --- a/drivers/rtc/nvmem.c
> +++ b/drivers/rtc/nvmem.c
> @@ -21,6 +21,7 @@ int devm_rtc_nvmem_register(struct rtc_device *rtc,
>
> nvmem_config->dev = dev;
> nvmem_config->owner = rtc->owner;
> + nvmem_config->use_fixed_of_cells = true;
> nvmem = devm_nvmem_register(dev, nvmem_config);
> if (IS_ERR(nvmem))
> dev_err(dev, "failed to register nvmem device for RTC\n");
> diff --git a/drivers/w1/slaves/w1_ds250x.c b/drivers/w1/slaves/w1_ds250x.c
> index 7592c7050d1d..538722b41f87 100644
> --- a/drivers/w1/slaves/w1_ds250x.c
> +++ b/drivers/w1/slaves/w1_ds250x.c
> @@ -168,6 +168,7 @@ static int w1_eprom_add_slave(struct w1_slave *sl)
> struct nvmem_device *nvmem;
> struct nvmem_config nvmem_cfg = {
> .dev = &sl->dev,
> + .use_fixed_of_cells = true,
> .reg_read = w1_nvmem_read,
> .type = NVMEM_TYPE_OTP,
> .read_only = true,
> diff --git a/include/linux/nvmem-provider.h b/include/linux/nvmem-provider.h
> index 0262b86194eb..b3c14ce87a65 100644
> --- a/include/linux/nvmem-provider.h
> +++ b/include/linux/nvmem-provider.h
> @@ -73,6 +73,7 @@ struct nvmem_cell_info {
> * @owner: Pointer to exporter module. Used for refcounting.
> * @cells: Optional array of pre-defined NVMEM cells.
> * @ncells: Number of elements in cells.
> + * @use_fixed_of_cells: Read fixed NVMEM cells from OF.
> * @keepout: Optional array of keepout ranges (sorted ascending by start).
> * @nkeepout: Number of elements in the keepout array.
> * @type: Type of the nvmem storage
> @@ -103,6 +104,7 @@ struct nvmem_config {
> struct module *owner;
> const struct nvmem_cell_info *cells;
> int ncells;
> + bool use_fixed_of_cells;
> const struct nvmem_keepout *keepout;
> unsigned int nkeepout;
> enum nvmem_type type;
More information about the linux-mtd
mailing list