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

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Submitter Wolfram Sang
Date Jan. 21, 2009, 5:41 p.m.
Message ID <1232559685-2268-3-git-send-email-w.sang@pengutronix.de>
Download mbox | patch
Permalink /patch/19682/
State Not Applicable
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Wolfram Sang - Jan. 21, 2009, 5:41 p.m.
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
Wolfram Sang - Jan. 24, 2009, 10:30 p.m.
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
>
Grant Likely - May 19, 2009, 2:57 p.m.
On Wed, Jan 21, 2009 at 11:41 AM, Wolfram Sang <w.sang@pengutronix.de> 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.

This is a new device tree binding.  It must be documented in
Documentation/powerpc/dts-bindings and posted to
devicetree-discuss@ozlabs.org for review.

> 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)

__devinit

> +{
> +       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);
> +       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;

Why isn't resource on the stack?

> +
> +       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;

I'd rather see more meaningful labels.  ie "err_kalloc:" and
"err_platram_probe:".

> +}
> +
> +static int of_ram_remove(struct of_device *op)

__devexit

> +{
> +       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 = {

__devinitdata

> +       .owner = THIS_MODULE,
> +       .name = "of-ram",

This name is too generic for an of_platform device.  'mtd' needs to be
in there somewhere.

> +       .match_table = of_ram_match,
> +       .probe = of_ram_probe,
> +       .remove = of_ram_remove,

__devexit_p()

> +};
> +
> +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);

Put the module_init() statement directly after the of_ram_init() definition.

> +module_exit(of_ram_exit);
> +
> +MODULE_AUTHOR("Wolfram Sang");
> +MODULE_DESCRIPTION("MTD OF RAM map driver");
> +MODULE_LICENSE("GPL v2");
> --
> 1.5.6.5
>
> _______________________________________________
> Linuxppc-dev mailing list
> Linuxppc-dev@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-dev
>
Wolfram Sang - May 19, 2009, 8:30 p.m.
Hi Grant,

thanks a lot for the review!

On Tue, May 19, 2009 at 08:57:15AM -0600, Grant Likely wrote:
> On Wed, Jan 21, 2009 at 11:41 AM, Wolfram Sang <w.sang@pengutronix.de> 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.
> 
> This is a new device tree binding.  It must be documented in
> Documentation/powerpc/dts-bindings and posted to
> devicetree-discuss@ozlabs.org for review.

Yeah, noticed that myself. I wanted to start another try to mainline this
driver next week, then also asking devicetree-discuss; will do it happily this
week, too :)

> 
> > 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)
> 
> __devinit

Oops, missed all of those.

> 
> > +{
> > +       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);
> > +       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;
> 
> Why isn't resource on the stack?

Point taken.

> 
> > +
> > +       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;
> 
> I'd rather see more meaningful labels.  ie "err_kalloc:" and
> "err_platram_probe:".

Okay.

> 
> > +}
> > +
> > +static int of_ram_remove(struct of_device *op)
> 
> __devexit
> 
> > +{
> > +       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 = {
> 
> __devinitdata
> 
> > +       .owner = THIS_MODULE,
> > +       .name = "of-ram",
> 
> This name is too generic for an of_platform device.  'mtd' needs to be
> in there somewhere.

Will "of-mtd-ram" do? (I'd think so)

> 
> > +       .match_table = of_ram_match,
> > +       .probe = of_ram_probe,
> > +       .remove = of_ram_remove,
> 
> __devexit_p()
> 
> > +};
> > +
> > +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);
> 
> Put the module_init() statement directly after the of_ram_init() definition.
> 
> > +module_exit(of_ram_exit);
> > +
> > +MODULE_AUTHOR("Wolfram Sang");
> > +MODULE_DESCRIPTION("MTD OF RAM map driver");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 1.5.6.5
> >
> > _______________________________________________
> > Linuxppc-dev mailing list
> > Linuxppc-dev@ozlabs.org
> > https://ozlabs.org/mailman/listinfo/linuxppc-dev
> >
> 
> 
> 
> -- 
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.

Will send V2 after some tests tomorrow...

Thanks,

   Wolfram
Grant Likely - May 19, 2009, 8:36 p.m.
On Tue, May 19, 2009 at 2:30 PM, Wolfram Sang <w.sang@pengutronix.de> wrote:
>> This name is too generic for an of_platform device.  'mtd' needs to be
>> in there somewhere.
>
> Will "of-mtd-ram" do? (I'd think so)

fine by me.

g
Wolfram Sang - May 21, 2009, 12:46 a.m.
Hello Grant,

as I am just working on V2 (fixed even some additional things), two more
questions came up:

On Tue, May 19, 2009 at 08:57:15AM -0600, Grant Likely wrote:
> On Wed, Jan 21, 2009 at 11:41 AM, Wolfram Sang <w.sang@pengutronix.de> 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.
> 
> This is a new device tree binding.  It must be documented in
> Documentation/powerpc/dts-bindings and posted to
> devicetree-discuss@ozlabs.org for review.
> 
> > 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)
> 
> __devinit
> 
> > +{
> > +       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);
> > +       if (!name) {
> > +               ret = -ENOENT;
> > +               dev_dbg(&op->dev, "could not get node name\n");
> > +               goto bad1;
> > +       }

Can I just use

	name = op->node->name

here? I wonder because of_device in asm/of_device.h states 'node' as "to be
obsoleted". And could I safely assume that all architectures will have the node
entry?

At least, I could drop the error check, if I understand booting-without-of
correctly? A name property will always be constructed, even if it is not
explicitly given.

> > +
> > +       resource = kzalloc(sizeof(struct resource), GFP_KERNEL);
> > +       if (!resource)
> > +               goto bad1;
> 
> Why isn't resource on the stack?
> 
> > +
> > +       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;
> 
> I'd rather see more meaningful labels.  ie "err_kalloc:" and
> "err_platram_probe:".
> 
> > +}
> > +
> > +static int of_ram_remove(struct of_device *op)
> 
> __devexit
> 
> > +{
> > +       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 = {
> 
> __devinitdata

I assume you mean the match_table and not the of_platform_driver. Shouldn't it
even better be const and using __devinitconst?

> 
> > +       .owner = THIS_MODULE,
> > +       .name = "of-ram",
> 
> This name is too generic for an of_platform device.  'mtd' needs to be
> in there somewhere.
> 
> > +       .match_table = of_ram_match,
> > +       .probe = of_ram_probe,
> > +       .remove = of_ram_remove,
> 
> __devexit_p()
> 
> > +};
> > +
> > +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);
> 
> Put the module_init() statement directly after the of_ram_init() definition.
> 
> > +module_exit(of_ram_exit);
> > +
> > +MODULE_AUTHOR("Wolfram Sang");
> > +MODULE_DESCRIPTION("MTD OF RAM map driver");
> > +MODULE_LICENSE("GPL v2");
> > --
> > 1.5.6.5
> >
> > _______________________________________________
> > Linuxppc-dev mailing list
> > Linuxppc-dev@ozlabs.org
> > https://ozlabs.org/mailman/listinfo/linuxppc-dev
> >
> 
> 
> 
> -- 
> Grant Likely, B.Sc., P.Eng.
> Secret Lab Technologies Ltd.
> 
> ______________________________________________________
> Linux MTD discussion mailing list
> http://lists.infradead.org/mailman/listinfo/linux-mtd/
Grant Likely - May 21, 2009, 4:21 a.m.
On Wed, May 20, 2009 at 6:46 PM, Wolfram Sang <w.sang@pengutronix.de> wrote:
>> > +       name = of_get_property(op->node, "name", NULL);
>> > +       if (!name) {
>> > +               ret = -ENOENT;
>> > +               dev_dbg(&op->dev, "could not get node name\n");
>> > +               goto bad1;
>> > +       }
>
> Can I just use
>
>        name = op->node->name
>
> here? I wonder because of_device in asm/of_device.h states 'node' as "to be
> obsoleted"
It may be labeled as such, but it's been so for over 2 years now, and
op->node is used all over the place.  I think Ben would like to
eventually move to using the node pointer in archdata, but that will
require a fair bit of refactoring.

Ben will kick me if I'm wrong, but I'll go out on a limb and say that
I think you're okay to use it.

>. And could I safely assume that all architectures will have the node
> entry?

All three current users do.

>> > +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 = {
>>
>> __devinitdata
>
> I assume you mean the match_table and not the of_platform_driver. Shouldn't it
> even better be const and using __devinitconst?

correct on both counts.

g.

Patch

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);
+	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");