[V3] nvmem: add explicit config option to read OF fixed cells
Commit Message
From: Rafał Miłecki <rafal@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)
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@milecki.pl>
[for meson-{efuse,mx-efuse}.c]
Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
[for mtk-efuse.c, nvmem/core.c, nvmem-provider.h]
Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
[MT8192, MT8195 Chromebooks]
Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
[for microchip-otpc.c]
Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
[SAMA7G5-EK]
Tested-by: Claudiu Beznea <claudiu.beznea@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(-)
Comments
Hi Rafał,
> 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.
I'm still unhappy with the naming, especially since you explained in
more details the whole plan which involves using a container to put
these fixed cells from now on. In both cases you extract cells from
fixed OF nodes but this boolean needs to be set to true in one
case, and false in the other, which would not make sense.
Also, regarding the bindings changes, I'm fairly happy with the idea,
but if we go this way I would prefer a full series instead of
individual changes with:
- the boolean you introduce here (renamed, at the very least)
- the new bindings
- the update of the current provider bindings to take the new bindings
into account and deprecate the old ones officially
- support for the new bindings in the core
> * @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;
Thanks,
Miquèl
On 9.03.2023 12:35, Miquel Raynal wrote:
>> 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.
>
> I'm still unhappy with the naming, especially since you explained in
> more details the whole plan which involves using a container to put
> these fixed cells from now on. In both cases you extract cells from
> fixed OF nodes but this boolean needs to be set to true in one
> case, and false in the other, which would not make sense.
>
> Also, regarding the bindings changes, I'm fairly happy with the idea,
> but if we go this way I would prefer a full series instead of
> individual changes with:
>
> - the boolean you introduce here (renamed, at the very least)
> - the new bindings
I assume you mean fixed-layout.yaml?
> - the update of the current provider bindings to take the new bindings
> into account and deprecate the old ones officially
What has to be updated in current proceds? It seems to me that:
1. Current NVMEM providers reference nvmem.yaml
2. nvmem.yaml references nvmem-layout.yaml
3. nvmem-layout.yaml references fixed-layout.yaml
what else is missing?
> - support for the new bindings in the core
Please, don't get me wrong, but I'm not going to spend more hours on
actual coding without approval of chosen path.
I'll need to have
[PATCH V2] dt-bindings: nvmem: layouts: add fixed-layout
reviewed/acked first. If you can do that that's great.
>> * @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;
>
> Thanks,
> Miquèl
Hi Rafał,
zajec5@gmail.com wrote on Thu, 9 Mar 2023 13:01:19 +0100:
> On 9.03.2023 12:35, Miquel Raynal wrote:
> >> 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.
> >
> > I'm still unhappy with the naming, especially since you explained in
> > more details the whole plan which involves using a container to put
> > these fixed cells from now on. In both cases you extract cells from
> > fixed OF nodes but this boolean needs to be set to true in one
> > case, and false in the other, which would not make sense.
> >
> > Also, regarding the bindings changes, I'm fairly happy with the idea,
> > but if we go this way I would prefer a full series instead of
> > individual changes with:
> >
> > - the boolean you introduce here (renamed, at the very least)
> > - the new bindings
>
> I assume you mean fixed-layout.yaml?
Yes!
> > - the update of the current provider bindings to take the new bindings
> > into account and deprecate the old ones officially
>
> What has to be updated in current proceds? It seems to me that:
> 1. Current NVMEM providers reference nvmem.yaml
> 2. nvmem.yaml references nvmem-layout.yaml
> 3. nvmem-layout.yaml references fixed-layout.yaml
>
> what else is missing?
That's the theory, but then provider bindings should reflect the
changes as well in their own binding documents.
IOW, this one (and all its cousins) becomes legacy and must be updated:
https://elixir.bootlin.com/linux/latest/source/Documentation/devicetree/bindings/nvmem/imx-ocotp.yaml#L92
(and there are many files to update then)
>
>
> > - support for the new bindings in the core
>
> Please, don't get me wrong, but I'm not going to spend more hours on
> actual coding without approval of chosen path.
Well, you want to make the bindings evolve. Just updating a single
binding file is not enough, I believe we should at least provide full
support for the new description. But of course I'm fine discussing what
description we want first.
> I'll need to have
> [PATCH V2] dt-bindings: nvmem: layouts: add fixed-layout
> reviewed/acked first. If you can do that that's great.
>
>
> >> * @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;
> >
> > Thanks,
> > Miquèl
>
Thanks,
Miquèl
On 09/03/2023 11:20, Rafał Miłecki wrote:
> From: Rafał Miłecki <rafal@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@milecki.pl>
> [for meson-{efuse,mx-efuse}.c]
> Acked-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
> [for mtk-efuse.c, nvmem/core.c, nvmem-provider.h]
> Reviewed-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> [MT8192, MT8195 Chromebooks]
> Tested-by: AngeloGioacchino Del Regno <angelogioacchino.delregno@collabora.com>
> [for microchip-otpc.c]
> Reviewed-by: Claudiu Beznea <claudiu.beznea@microchip.com>
> [SAMA7G5-EK]
> Tested-by: Claudiu Beznea <claudiu.beznea@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;
On 10.03.2023 10:22, Srinivas Kandagatla wrote:
>
> On 09/03/2023 11:20, Rafał Miłecki wrote:
>> From: Rafał Miłecki <rafal@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
I updated commit message to address your concerns. I thought I made it
clear. I don't know how to emphasize it better.
I'll try to answer nevertheless, please see below.
On 9.03.2023 10:37, Srinivas Kandagatla wrote:
> On 24/02/2023 07:29, Rafał Miłecki wrote:
>> From: Rafał Miłecki <rafal@milecki.pl>
>>
>> NVMEM subsystem looks for fixed NVMEM cells (specified in DT) by
>> default. This behaviour made sense in early days before adding support
>> for dynamic cells.
>>
>> With every new supported NVMEM device with dynamic cells current
>> behaviour becomes non-optimal. It results in unneeded iterating over DT
>> nodes and may result in false discovery of cells (depending on used DT
>> properties).
>
>>
>> This behaviour has actually caused a problem already with the MTD
>> subsystem. MTD subpartitions were incorrectly treated as NVMEM cells.
>>
>> Also with upcoming support for NVMEM layouts no new binding or driver
>> should support fixed cells defined in device node.
>
> This is not very clear, are you saying that we should not support fixed cells? If that is the case then you are proabably taking this in wrong direction. nvmem was built based on the fact that drivers can read from a fixed offsets. Dynamic cells is something very new, that does not mean that we should ditch fixed cells support in dt.
I DON'T deprecate or drop support for fixed layouts (fixed NVMEM cells).
Period.
I WON'T drop support for old binding. We stay backward compatible.
Period.
In this patch's body I wrote:
"with the support for NVMEM layouts we may & should have *new* bindings allow fixed NVMEM cells only in the "nvmem-layout" subnode"
that clearly means I still want to ALLOW fixed NVMEM cells - just in the *nvmem-layout* node.
I want to KEEP support for fixed NVMEM cells.
I just want them to be preferably defined in the "nvmem-layout" node.
>> Solve this by modifying drivers for bindings that support specifying
>> fixed NVMEM cells in DT. Make them explicitly tell NVMEM subsystem to
>> read cells from DT.
>
> Shouldn't this be opposite, let the new providers tell that cells are created at runtime?
>
> or even better if there is a way to detect if we can set this flag dynamically based on layout/post-processing configuration.
>
> that should be much cleaner approch.
I tried to address this concert in the following part of commit body:
> 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.
New NVMEM provider bindings and drivers will get developed. I would
want all new bindings to use "nvmem-layout" for describing NVMEM cells
(no matter if fixed or dynamic).
That means all new drivers WILL NOT need to set "use_fixed_of_cells".
So over time "use_fixed_of_cells" will become a minority. It'w would be
pitty to have every new driver to request NVMEM code to skip looking for
NVMEM cells in **device** node.
So my answer is: no. I don't believe it should be opposite. Looking for
fixed NVMEM cells in **device** DT node should be an opt-in.
If by some miracle I manage to get my patches through then you'll forget
about "use_fixed_of_cells" next month. Noone will need it for any new
stuff. It'll stay for backward compatibility only.
@@ -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;
@@ -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),
@@ -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);
@@ -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,
@@ -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;
@@ -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;
@@ -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;
@@ -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);
@@ -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;
@@ -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;
@@ -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,
@@ -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;
@@ -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,
@@ -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");
@@ -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;
@@ -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;
@@ -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,
@@ -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;
@@ -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);
@@ -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;
@@ -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");
@@ -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,
@@ -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;