From: Rafał Miłecki <[email protected]>
NVMEM on some devices can be accessed using I/O mapping. For example on
Broadcom MIPS and ARM Northstar platforms NVRAM can be accessed that
way.
Signed-off-by: Rafał Miłecki <[email protected]>
---
.../devicetree/bindings/nvmem/iomap.yaml | 29 +++++++++++++++++++
1 file changed, 29 insertions(+)
create mode 100644 Documentation/devicetree/bindings/nvmem/iomap.yaml
diff --git a/Documentation/devicetree/bindings/nvmem/iomap.yaml b/Documentation/devicetree/bindings/nvmem/iomap.yaml
new file mode 100644
index 000000000000..ec8764598061
--- /dev/null
+++ b/Documentation/devicetree/bindings/nvmem/iomap.yaml
@@ -0,0 +1,29 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/nvmem/iomap.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: I/O mapped NVMEM
+
+maintainers:
+ - Rafał Miłecki <[email protected]>
+
+allOf:
+ - $ref: "nvmem.yaml#"
+
+properties:
+ compatible:
+ items:
+ - enum:
+ - brcm,nvram
+ - const: nvmem-iomap
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ nvram@1eff0000 {
+ compatible = "brcm,nvram", "nvmem-iomap";
+ reg = <0x1eff0000 0x10000>;
+ };
--
2.26.2
From: Rafał Miłecki <[email protected]>
This is a generic NVMEM access method used e.g. by Broadcom for their
NVRAM on MIPS and Northstar devices.
Signed-off-by: Rafał Miłecki <[email protected]>
---
drivers/nvmem/Kconfig | 7 +++
drivers/nvmem/Makefile | 2 +
drivers/nvmem/iomap.c | 99 ++++++++++++++++++++++++++++++++++++++++++
3 files changed, 108 insertions(+)
create mode 100644 drivers/nvmem/iomap.c
diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
index 75d2594c16e1..3d5c5684685d 100644
--- a/drivers/nvmem/Kconfig
+++ b/drivers/nvmem/Kconfig
@@ -278,4 +278,11 @@ config NVMEM_RMEM
This driver can also be built as a module. If so, the module
will be called nvmem-rmem.
+
+config NVMEM_IOMAP
+ tristate "I/O mapped NVMEM support"
+ depends on HAS_IOMEM
+ help
+ This driver supports NVMEM that can be accessed using I/O mapping.
+
endif
diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
index 5376b8e0dae5..88a3b6979c53 100644
--- a/drivers/nvmem/Makefile
+++ b/drivers/nvmem/Makefile
@@ -57,3 +57,5 @@ obj-$(CONFIG_SPRD_EFUSE) += nvmem_sprd_efuse.o
nvmem_sprd_efuse-y := sprd-efuse.o
obj-$(CONFIG_NVMEM_RMEM) += nvmem-rmem.o
nvmem-rmem-y := rmem.o
+obj-$(CONFIG_NVMEM_IOMAP) += nvmem_iomap.o
+nvmem_iomap-y := iomap.o
diff --git a/drivers/nvmem/iomap.c b/drivers/nvmem/iomap.c
new file mode 100644
index 000000000000..ab6b40858a64
--- /dev/null
+++ b/drivers/nvmem/iomap.c
@@ -0,0 +1,99 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2021 Rafał Miłecki <[email protected]>
+ */
+
+#include <linux/io.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/nvmem-provider.h>
+#include <linux/platform_device.h>
+
+struct iomap {
+ struct device *dev;
+ void __iomem *base;
+};
+
+static int iomap_read(void *context, unsigned int offset, void *val,
+ size_t bytes)
+{
+ struct iomap *priv = context;
+ u8 *src = priv->base + offset;
+ u8 *dst = val;
+ size_t tmp;
+
+ tmp = offset % 4;
+ memcpy_fromio(dst, src, tmp);
+ dst += tmp;
+ src += tmp;
+ bytes -= tmp;
+
+ tmp = rounddown(bytes, 4);
+ __ioread32_copy(dst, src, tmp / 4);
+ dst += tmp;
+ src += tmp;
+ bytes -= tmp;
+
+ memcpy_fromio(dst, src, bytes);
+
+ return 0;
+}
+
+static int iomap_probe(struct platform_device *pdev)
+{
+ struct nvmem_config config = {
+ .name = "iomap",
+ .reg_read = iomap_read,
+ };
+ struct device *dev = &pdev->dev;
+ struct resource *res;
+ struct iomap *priv;
+
+ priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
+ if (!priv)
+ return -ENOMEM;
+ priv->dev = dev;
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ dev_err(dev, "Failed to get resource\n");
+ return -ENODEV;
+ }
+
+ priv->base = devm_ioremap_resource(dev, res);
+ if (IS_ERR(priv->base)) {
+ dev_err(dev, "Failed to map resource: %ld\n", PTR_ERR(priv->base));
+ return PTR_ERR(priv->base);
+ }
+
+ config.dev = dev;
+ config.priv = priv;
+ config.size = resource_size(res);
+
+ return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
+}
+
+static const struct of_device_id iomap_of_match_table[] = {
+ { .compatible = "brcm,nvram", },
+ { .compatible = "nvmem-iomap", },
+ {},
+};
+
+static struct platform_driver iomap_driver = {
+ .probe = iomap_probe,
+ .driver = {
+ .name = "nvmem_iomap",
+ .of_match_table = iomap_of_match_table,
+ },
+};
+
+static int __init iomap_init(void)
+{
+ return platform_driver_register(&iomap_driver);
+}
+
+subsys_initcall_sync(iomap_init);
+
+MODULE_AUTHOR("Rafał Miłecki");
+MODULE_LICENSE("GPL v2");
+MODULE_DEVICE_TABLE(of, iomap_of_match_table);
--
2.26.2
On 04/03/2021 14:41, Rafał Miłecki wrote:
> From: Rafał Miłecki <[email protected]>
>
> This is a generic NVMEM access method used e.g. by Broadcom for their
> NVRAM on MIPS and Northstar devices.
>
> Signed-off-by: Rafał Miłecki <[email protected]>
> ---
> drivers/nvmem/Kconfig | 7 +++
> drivers/nvmem/Makefile | 2 +
> drivers/nvmem/iomap.c | 99 ++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 108 insertions(+)
> create mode 100644 drivers/nvmem/iomap.c
>
> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
> index 75d2594c16e1..3d5c5684685d 100644
> --- a/drivers/nvmem/Kconfig
> +++ b/drivers/nvmem/Kconfig
> @@ -278,4 +278,11 @@ config NVMEM_RMEM
>
> This driver can also be built as a module. If so, the module
> will be called nvmem-rmem.
> +
> +config NVMEM_IOMAP
> + tristate "I/O mapped NVMEM support"
> + depends on HAS_IOMEM
> + help
> + This driver supports NVMEM that can be accessed using I/O mapping.
> +
> endif
> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
> index 5376b8e0dae5..88a3b6979c53 100644
> --- a/drivers/nvmem/Makefile
> +++ b/drivers/nvmem/Makefile
> @@ -57,3 +57,5 @@ obj-$(CONFIG_SPRD_EFUSE) += nvmem_sprd_efuse.o
> nvmem_sprd_efuse-y := sprd-efuse.o
> obj-$(CONFIG_NVMEM_RMEM) += nvmem-rmem.o
> nvmem-rmem-y := rmem.o
> +obj-$(CONFIG_NVMEM_IOMAP) += nvmem_iomap.o
> +nvmem_iomap-y := iomap.o
> diff --git a/drivers/nvmem/iomap.c b/drivers/nvmem/iomap.c
> new file mode 100644
> index 000000000000..ab6b40858a64
> --- /dev/null
> +++ b/drivers/nvmem/iomap.c
> @@ -0,0 +1,99 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (C) 2021 Rafał Miłecki <[email protected]>
> + */
> +
> +#include <linux/io.h>
> +#include <linux/mod_devicetable.h>
> +#include <linux/module.h>
> +#include <linux/nvmem-provider.h>
> +#include <linux/platform_device.h>
> +
> +struct iomap {
> + struct device *dev;
> + void __iomem *base;
> +};
> +
> +static int iomap_read(void *context, unsigned int offset, void *val,
> + size_t bytes)
> +{
> + struct iomap *priv = context;
> + u8 *src = priv->base + offset;
> + u8 *dst = val;
> + size_t tmp;
> +
> + tmp = offset % 4;
> + memcpy_fromio(dst, src, tmp);
> + dst += tmp;
> + src += tmp;
> + bytes -= tmp;
> +
> + tmp = rounddown(bytes, 4);
> + __ioread32_copy(dst, src, tmp / 4);
> + dst += tmp;
> + src += tmp;
> + bytes -= tmp;
> +
> + memcpy_fromio(dst, src, bytes);
> +
You could just do this!
while (bytes--)
*val++ = readb(priv->base + offset + i++);
> + return 0;
> +}
> +
> +static int iomap_probe(struct platform_device *pdev)
> +{
> + struct nvmem_config config = {
> + .name = "iomap",
> + .reg_read = iomap_read,
> + };
> + struct device *dev = &pdev->dev;
> + struct resource *res;
> + struct iomap *priv;
> +
> + priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
> + if (!priv)
> + return -ENOMEM;
> + priv->dev = dev;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + if (!res) {
> + dev_err(dev, "Failed to get resource\n");
> + return -ENODEV;
> + }
This is redundant check and error message!
You can just do :
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
priv->base = devm_ioremap_resource(dev, res);
> +
> + priv->base = devm_ioremap_resource(dev, res);
> + if (IS_ERR(priv->base)) {
> + dev_err(dev, "Failed to map resource: %ld\n", PTR_ERR(priv->base));
This message is redundant!
> + return PTR_ERR(priv->base);
> + }
> +
> + config.dev = dev;
> + config.priv = priv;
> + config.size = resource_size(res);
> +
> + return PTR_ERR_OR_ZERO(devm_nvmem_register(dev, &config));
> +}
> +
> +static const struct of_device_id iomap_of_match_table[] = {
> + { .compatible = "brcm,nvram", },
> + { .compatible = "nvmem-iomap", },
Generic compatible does not really makes sense at all, you can probably
consider adding some generic functions rather than having a compatible,
in case you want to reduce code duplication!
> + {},
> +};
> +
> +static struct platform_driver iomap_driver = {
> + .probe = iomap_probe,
> + .driver = {
> + .name = "nvmem_iomap",
> + .of_match_table = iomap_of_match_table,
> + },
> +};
> +
> +static int __init iomap_init(void)
> +{
> + return platform_driver_register(&iomap_driver);
> +}
> +
> +subsys_initcall_sync(iomap_init);
> +
> +MODULE_AUTHOR("Rafał Miłecki");
> +MODULE_LICENSE("GPL v2");
it should be
MODULE_LICENSE("GPL");
> +MODULE_DEVICE_TABLE(of, iomap_of_match_table);
>
On 05/03/2021 10:24, Rafał Miłecki wrote:
>>>
>>> +static int iomap_read(void *context, unsigned int offset, void *val,
>>> + size_t bytes)
>>> +{
>>> + struct iomap *priv = context;
>>> + u8 *src = priv->base + offset;
>>> + u8 *dst = val;
>>> + size_t tmp;
>>> +
>>> + tmp = offset % 4;
>>> + memcpy_fromio(dst, src, tmp);
>>> + dst += tmp;
>>> + src += tmp;
>>> + bytes -= tmp;
>>> +
>>> + tmp = rounddown(bytes, 4);
>>> + __ioread32_copy(dst, src, tmp / 4);
>>> + dst += tmp;
>>> + src += tmp;
>>> + bytes -= tmp;
>>> +
>>> + memcpy_fromio(dst, src, bytes);
>>> +
>>
>>
>> You could just do this!
>>
>> while (bytes--)
>> *val++ = readb(priv->base + offset + i++);
>
> Do you mean that as replacement for "memcpy_fromio" or the whole
> function code?
Yes please!
> The reason for using __ioread32_copy() was to improve reading
> performance (using aligned 32 bit access where possible). I'm not sure
> if that really matters?
Just simple while loop is much readable than the previous code TBH!
>
> P.S.
> Please don't yell at me in every sentence :( Makes me a bit sad :(
Sorry!! I did not mean anything as such! :-)
--srini
On 05.03.2021 11:02, Srinivas Kandagatla wrote:
> On 04/03/2021 14:41, Rafał Miłecki wrote:
>> From: Rafał Miłecki <[email protected]>
>>
>> This is a generic NVMEM access method used e.g. by Broadcom for their
>> NVRAM on MIPS and Northstar devices.
>>
>> Signed-off-by: Rafał Miłecki <[email protected]>
>> ---
>> drivers/nvmem/Kconfig | 7 +++
>> drivers/nvmem/Makefile | 2 +
>> drivers/nvmem/iomap.c | 99 ++++++++++++++++++++++++++++++++++++++++++
>> 3 files changed, 108 insertions(+)
>> create mode 100644 drivers/nvmem/iomap.c
>>
>> diff --git a/drivers/nvmem/Kconfig b/drivers/nvmem/Kconfig
>> index 75d2594c16e1..3d5c5684685d 100644
>> --- a/drivers/nvmem/Kconfig
>> +++ b/drivers/nvmem/Kconfig
>> @@ -278,4 +278,11 @@ config NVMEM_RMEM
>> This driver can also be built as a module. If so, the module
>> will be called nvmem-rmem.
>> +
>> +config NVMEM_IOMAP
>> + tristate "I/O mapped NVMEM support"
>> + depends on HAS_IOMEM
>> + help
>> + This driver supports NVMEM that can be accessed using I/O mapping.
>> +
>> endif
>> diff --git a/drivers/nvmem/Makefile b/drivers/nvmem/Makefile
>> index 5376b8e0dae5..88a3b6979c53 100644
>> --- a/drivers/nvmem/Makefile
>> +++ b/drivers/nvmem/Makefile
>> @@ -57,3 +57,5 @@ obj-$(CONFIG_SPRD_EFUSE) += nvmem_sprd_efuse.o
>> nvmem_sprd_efuse-y := sprd-efuse.o
>> obj-$(CONFIG_NVMEM_RMEM) += nvmem-rmem.o
>> nvmem-rmem-y := rmem.o
>> +obj-$(CONFIG_NVMEM_IOMAP) += nvmem_iomap.o
>> +nvmem_iomap-y := iomap.o
>> diff --git a/drivers/nvmem/iomap.c b/drivers/nvmem/iomap.c
>> new file mode 100644
>> index 000000000000..ab6b40858a64
>> --- /dev/null
>> +++ b/drivers/nvmem/iomap.c
>> @@ -0,0 +1,99 @@
>> +// SPDX-License-Identifier: GPL-2.0-only
>> +/*
>> + * Copyright (C) 2021 Rafał Miłecki <[email protected]>
>> + */
>> +
>> +#include <linux/io.h>
>> +#include <linux/mod_devicetable.h>
>> +#include <linux/module.h>
>> +#include <linux/nvmem-provider.h>
>> +#include <linux/platform_device.h>
>> +
>> +struct iomap {
>> + struct device *dev;
>> + void __iomem *base;
>> +};
>> +
>> +static int iomap_read(void *context, unsigned int offset, void *val,
>> + size_t bytes)
>> +{
>> + struct iomap *priv = context;
>> + u8 *src = priv->base + offset;
>> + u8 *dst = val;
>> + size_t tmp;
>> +
>> + tmp = offset % 4;
>> + memcpy_fromio(dst, src, tmp);
>> + dst += tmp;
>> + src += tmp;
>> + bytes -= tmp;
>> +
>> + tmp = rounddown(bytes, 4);
>> + __ioread32_copy(dst, src, tmp / 4);
>> + dst += tmp;
>> + src += tmp;
>> + bytes -= tmp;
>> +
>> + memcpy_fromio(dst, src, bytes);
>> +
>
>
> You could just do this!
>
> while (bytes--)
> *val++ = readb(priv->base + offset + i++);
Do you mean that as replacement for "memcpy_fromio" or the whole
function code?
The reason for using __ioread32_copy() was to improve reading
performance (using aligned 32 bit access where possible). I'm not sure
if that really matters?
P.S.
Please don't yell at me in every sentence :( Makes me a bit sad :(
On 05.03.2021 11:33, Srinivas Kandagatla wrote:
> On 05/03/2021 10:24, Rafał Miłecki wrote:
>>>>
>>>> +static int iomap_read(void *context, unsigned int offset, void *val,
>>>> + size_t bytes)
>>>> +{
>>>> + struct iomap *priv = context;
>>>> + u8 *src = priv->base + offset;
>>>> + u8 *dst = val;
>>>> + size_t tmp;
>>>> +
>>>> + tmp = offset % 4;
>>>> + memcpy_fromio(dst, src, tmp);
>>>> + dst += tmp;
>>>> + src += tmp;
>>>> + bytes -= tmp;
>>>> +
>>>> + tmp = rounddown(bytes, 4);
>>>> + __ioread32_copy(dst, src, tmp / 4);
>>>> + dst += tmp;
>>>> + src += tmp;
>>>> + bytes -= tmp;
>>>> +
>>>> + memcpy_fromio(dst, src, bytes);
>>>> +
>>>
>>>
>>> You could just do this!
>>>
>>> while (bytes--)
>>> *val++ = readb(priv->base + offset + i++);
>>
>> Do you mean that as replacement for "memcpy_fromio" or the whole
>> function code?
>
> Yes please!
>
>> The reason for using __ioread32_copy() was to improve reading
>> performance (using aligned 32 bit access where possible). I'm not sure
>> if that really matters?
>
> Just simple while loop is much readable than the previous code TBH!
>
>>
>
>> P.S.
>> Please don't yell at me in every sentence :( Makes me a bit sad :(
> Sorry!! I did not mean anything as such! :-)
All clear (I hope)! Thanks for your review!