| Message ID | 20210304144132.24098-1-zajec5@gmail.com |
|---|---|
| State | New |
| Headers | show |
| Series | [1/2] dt-bindings: nvmem: add binding for I/O mapped NVMEM | expand |
On 04/03/2021 14:41, Rafał Miłecki wrote: > From: Rafał Miłecki <rafal@milecki.pl> > > 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 <rafal@milecki.pl> > --- > 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 <rafal@milecki.pl> > + */ > + > +#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 11:02, Srinivas Kandagatla wrote: > On 04/03/2021 14:41, Rafał Miłecki wrote: >> From: Rafał Miłecki <rafal@milecki.pl> >> >> 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 <rafal@milecki.pl> >> --- >> 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 <rafal@milecki.pl> >> + */ >> + >> +#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 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 11:33, 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!
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 <rafal@milecki.pl> + +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>; + };