On 05.03.2021 11:02, Srinivas Kandagatla wrote:
On 04/03/2021 14:41, Rafał Miłecki wrote:From: Rafał Miłecki <rafal@xxxxxxxxxx> 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@xxxxxxxxxx> --- 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@xxxxxxxxxx> + */ + +#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 :(
