Re: [PATCH 2/2] maps/mtd-ram: add an of-platform driver

Wolfram Sang
2009-01-24T22:30:46Z

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Hello,

found one question thing myself...

On Wed, Jan 21, 2009 at 06:41:25PM +0100, Wolfram Sang wrote:
> Create an of-aware driver using the now exported generic functions from
> plat-ram.c. A typical oftree snipplet for it looks like this:
>
> sram@04e00000 {
> compatible = "mtd-ram";
> reg = <0x04e00000 0x00200000>;
> bank-width = <2>;
> };
>
> Partitions on this device are not yet supported.
>
> Signed-off-by: Wolfram Sang <w.sang@pengutronix.de>
> ---
> drivers/mtd/maps/Kconfig | 6 ++
> drivers/mtd/maps/Makefile | 1 +
> drivers/mtd/maps/of-ram.c | 120 +++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 127 insertions(+), 0 deletions(-)
> create mode 100644 drivers/mtd/maps/of-ram.c
>
> diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig
> index 0225cbb..b238b6d 100644
> --- a/drivers/mtd/maps/Kconfig
> +++ b/drivers/mtd/maps/Kconfig
> @@ -551,5 +551,11 @@ config MTD_PLATRAM
>
> This selection automatically selects the map_ram driver.
>
> +config MTD_OFRAM
> + tristate "Map driver for of-device RAM (mtd-ram)"
> + depends on MTD_PLATRAM && OF
> + help
> + Map driver for RAM areas described via the of-device
> + system.
> endmenu
>
> diff --git a/drivers/mtd/maps/Makefile b/drivers/mtd/maps/Makefile
> index 6d9ba35..f8e3908 100644
> --- a/drivers/mtd/maps/Makefile
> +++ b/drivers/mtd/maps/Makefile
> @@ -58,6 +58,7 @@ obj-$(CONFIG_MTD_WRSBC8260) += wr_sbc82xx_flash.o
> obj-$(CONFIG_MTD_DMV182) += dmv182.o
> obj-$(CONFIG_MTD_SHARP_SL) += sharpsl-flash.o
> obj-$(CONFIG_MTD_PLATRAM) += plat-ram.o
> +obj-$(CONFIG_MTD_OFRAM) += of-ram.o
> obj-$(CONFIG_MTD_OMAP_NOR) += omap_nor.o
> obj-$(CONFIG_MTD_INTEL_VR_NOR) += intel_vr_nor.o
> obj-$(CONFIG_MTD_BFIN_ASYNC) += bfin-async-flash.o
> diff --git a/drivers/mtd/maps/of-ram.c b/drivers/mtd/maps/of-ram.c
> new file mode 100644
> index 0000000..4d334a9
> --- /dev/null
> +++ b/drivers/mtd/maps/of-ram.c
> @@ -0,0 +1,120 @@
> +/*
> + * drivers/mtd/maps/of-ram.c
> + *
> + * Generic of device based RAM map
> + *
> + * Copyright (C) 2009 Wolfram Sang, Pengutronix
> + *
> + * Using plat-ram.c by Ben Dooks
> + *
> + * This program is free software; you can redistribute it and/or modify it
> + * under the terms of the GNU General Public License version 2 as published by
> + * the Free Software Foundation.
> + */
> +
> +#include <linux/module.h>
> +#include <linux/types.h>
> +#include <linux/init.h>
> +#include <linux/kernel.h>
> +#include <linux/device.h>
> +#include <linux/platform_device.h>
> +#include <linux/of_device.h>
> +#include <linux/of_platform.h>
> +#include <linux/mtd/plat-ram.h>
> +
> +static int of_ram_probe(struct of_device *op, const struct of_device_id *match)
> +{
> + struct platdata_mtd_ram *pdata;
> + struct resource *resource;
> + const char *name;
> + const u32 *bankwidth;
> + int ret = -ENOMEM;
> +
> + pdata = kzalloc(sizeof(*pdata), GFP_KERNEL);
> + if (!pdata)
> + goto bad0;
> + op->dev.platform_data = pdata;
> +
> + name = of_get_property(op->node, "name", NULL);

As this pointer gets passed on and used, I must probably add something
like of_node_get(op->node) here and put the node later in the remove
function? Not 100% sure, though...

> + if (!name) {
> + ret = -ENOENT;
> + dev_dbg(&op->dev, "could not get node name\n");
> + goto bad1;
> + }
> +
> + resource = kzalloc(sizeof(struct resource), GFP_KERNEL);
> + if (!resource)
> + goto bad1;
> +
> + if (of_address_to_resource(op->node, 0, resource)) {
> + ret = -ENXIO;
> + dev_dbg(&op->dev, "could not create resource\n");
> + goto bad2;
> + }
> +
> + bankwidth = of_get_property(op->node, "bank-width", NULL);
> + if (*bankwidth == 0) {
> + ret = -ENOENT;
> + dev_dbg(&op->dev, "bank width not set\n");
> + goto bad2;
> + }
> + pdata->bankwidth = *bankwidth;
> +
> + ret = __platram_probe(&op->dev, name, resource, pdata);
> + kfree(resource);
> +
> + if (ret)
> + goto bad1;
> +
> + return 0;
> +
> + bad2:
> + kfree(resource);
> + bad1:
> + op->dev.platform_data = NULL;
> + kfree(pdata);
> + bad0:
> + return ret;
> +}
> +
> +static int of_ram_remove(struct of_device *op)
> +{
> + int ret;
> + struct platdata_mtd_ram *pdata = op->dev.platform_data;
> +
> + ret = __platram_remove(&op->dev);
> + op->dev.platform_data = NULL;
> + kfree(pdata);
> + return ret;
> +}
> +
> +static struct of_device_id of_ram_match[] = {
> + { .compatible = "mtd-ram", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, of_ram_match);
> +
> +static struct of_platform_driver of_ram_driver = {
> + .owner = THIS_MODULE,
> + .name = "of-ram",
> + .match_table = of_ram_match,
> + .probe = of_ram_probe,
> + .remove = of_ram_remove,
> +};
> +
> +static int __init of_ram_init(void)
> +{
> + return of_register_platform_driver(&of_ram_driver);
> +}
> +
> +static void __exit of_ram_exit(void)
> +{
> + of_unregister_platform_driver(&of_ram_driver);
> +}
> +
> +module_init(of_ram_init);
> +module_exit(of_ram_exit);
> +
> +MODULE_AUTHOR("Wolfram Sang");
> +MODULE_DESCRIPTION("MTD OF RAM map driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.5.6.5
>

--
Dipl.-Ing. Wolfram Sang | http://www.pengutronix.de
Pengutronix - Linux Solutions for Science and Industry

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