Re: [PATCH 2/2] nvmem: iomap: new driver exposing NVMEM accessible using I/O mapping
From: Srinivas Kandagatla <hidden>
Date: 2021-03-05 10:03:23
Also in:
linux-devicetree, linux-mips, lkml
On 04/03/2021 14:41, Rafał Miłecki wrote:
quoted hunk ↗ jump to hunk
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.cdiff --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. + endifdiff --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.odiff --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);
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