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

[Wolfram Sang <w.sang@pengutronix.de>]

[-- Attachment #1: Type: text/plain, Size: 5379 bytes --]

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

[-- Attachment #2: Digital signature --]
[-- Type: application/pgp-signature, Size: 197 bytes --]