[RFC] Make physmap into a platform device driver...

[RFC] Make physmap into a platform device driver...

[Deepak Saxena]

I'm working on a system where I want to use the physmap driver
but the size or buswidth of the flash device might change depending
on the specific board layout. I want to be able to build a single kernel
that boots on all boards using this NPU (IXP2350) and with the hardcoded
approach to buswidth and such, it makes it rather impossible. On ARM
platforms, we've been using the following data structure to pass
board-specific flash information to the SOC-specific drivers and I 
am wondering if it makes sense to move it out of ARM into the generic
MTD layer and have the physmap driver use it. The physmap driver
could register itself as a platform driver for "phys-mtd" devices
and boards would just fill in platform_device structure with the
appropriate resource window and the needed fields below as the
platform_data. We may want to trim down the structure to remove 
ARM-specific fields and let ARM have it's own structure that contains
the generic structure as a member. Thoughts?

~Deepak

/*
 * map_name:	the map probe function name
 * name:	flash device name (eg, as used with mtdparts=)
 * width:	width of mapped device
 * init:	method called at driver/device initialisation
 * exit:	method called at driver/device removal
 * set_vpp:	method called to enable or disable VPP
 * mmcontrol:	method called to enable or disable Sync. Burst Read in OneNAND
 * parts:	optional array of mtd_partitions for static partitioning
 * nr_parts:	number of mtd_partitions for static partitoning
 */
struct flash_platform_data {
	const char	*map_name;
	const char	*name;
	unsigned int	width;
	int		(*init)(void);
	void		(*exit)(void);
	void		(*set_vpp)(int on);
	void		(*mmcontrol)(struct mtd_info *mtd, int sync_read);
	struct mtd_partition *parts;
	unsigned int	nr_parts;
};


-- 
Deepak Saxena - dsaxena@plexity.net - http://www.plexity.net

A starving child in Africa or you in front of your TV?
Where's the real tragedy?

Re: [RFC] Make physmap into a platform device driver...

[Mark Brown]

[-- Attachment #1: Type: text/plain, Size: 10259 bytes --]

On Thu, Dec 29, 2005 at 03:21:38PM -0800, Deepak Saxena wrote:

> MTD layer and have the physmap driver use it. The physmap driver
> could register itself as a platform driver for "phys-mtd" devices
> and boards would just fill in platform_device structure with the
> appropriate resource window and the needed fields below as the
> platform_data. We may want to trim down the structure to remove 
> ARM-specific fields and let ARM have it's own structure that contains
> the generic structure as a member. Thoughts?

An alternative approach (which Jason Gunthorpe posted a patch for
recently IIRC) is to add probe support to the plat-ram driver so it can
work with any kind of chip.  I have a patch kicking around doing pretty
much that but also renaming the driver to make it look less strange when
used.

My patch is below - it probably ought to have the re-addition of write
protection methods which I had stripped out since I've got partially
written support for paging in chips and thought the two might end up
related.

diff -uprN linux-2.6.13/drivers/mtd/maps/Kconfig linux-plat-flash/drivers/mtd/maps/Kconfig
--- linux-2.6.13/drivers/mtd/maps/Kconfig	2005-08-29 00:41:01.000000000 +0100
+++ linux-plat-flash/drivers/mtd/maps/Kconfig	2005-09-08 18:51:13.984319480 +0100
@@ -624,5 +624,12 @@ config MTD_PLATRAM
 
 	  This selection automatically selects the map_ram driver.
 
+config MTD_PLATFLASH
+	tristate "Map driver for platform device physically mapped flash"
+	depends on MTD
+	help
+	  Map driver allowing MTD devices which are physically mapped into
+	  the CPU's address space to be enumerated using the platform bus.
+
 endmenu
 
diff -uprN linux-2.6.13/drivers/mtd/maps/Makefile linux-plat-flash/drivers/mtd/maps/Makefile
--- linux-2.6.13/drivers/mtd/maps/Makefile	2005-08-29 00:41:01.000000000 +0100
+++ linux-plat-flash/drivers/mtd/maps/Makefile	2005-09-08 18:51:08.706121888 +0100
@@ -69,4 +69,5 @@ obj-$(CONFIG_MTD_WRSBC8260)	+= wr_sbc82x
 obj-$(CONFIG_MTD_DMV182)	+= dmv182.o
 obj-$(CONFIG_MTD_SHARP_SL)	+= sharpsl-flash.o
 obj-$(CONFIG_MTD_PLATRAM)	+= plat-ram.o
+obj-$(CONFIG_MTD_PLATFLASH)     += plat-flash.o
 obj-$(CONFIG_MTD_OMAP_NOR)	+= omap_nor.o
diff -uprN linux-2.6.13/drivers/mtd/maps/plat-flash.c linux-plat-flash/drivers/mtd/maps/plat-flash.c
--- linux-2.6.13/drivers/mtd/maps/plat-flash.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-plat-flash/drivers/mtd/maps/plat-flash.c	2005-09-08 18:48:56.711188168 +0100
@@ -0,0 +1,270 @@
+/* drivers/mtd/maps/plat-flash.c
+ *
+ * (c) 2004-2005 Simtec Electronics
+ *	http://www.simtec.co.uk/products/SWLINUX/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * Generic platform device based flash mappings.
+ *
+ * $Id: $
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/ioport.h>
+#include <linux/device.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/plat-flash.h>
+
+#include <asm/io.h>
+
+/* private structure for each mtd platform ram device created */
+
+struct platflash_info {
+	struct device		*dev;
+	struct mtd_info		*mtd;
+	struct map_info		 map;
+	struct mtd_partition	*partitions;
+	struct resource		*area;
+};
+
+/* to_platflash_info()
+ *
+ * device private data to struct platflash_info conversion
+*/
+
+static inline struct platflash_info *to_platflash_info(struct device *dev)
+{
+	return (struct platflash_info *)dev_get_drvdata(dev);
+}
+
+/* platflash_remove
+ *
+ * called to remove the device from the driver's control
+*/
+
+static int platflash_remove(struct device *dev)
+{
+	struct platflash_info *info = to_platflash_info(dev);
+
+	dev_set_drvdata(dev, NULL);
+
+	dev_dbg(dev, "removing device\n");
+
+	if (info == NULL) 
+		return 0;
+
+	if (info->mtd) {
+#ifdef CONFIG_MTD_PARTITIONS
+		if (info->partitions) {
+			del_mtd_partitions(info->mtd);
+			kfree(info->partitions);
+		}
+#endif
+		del_mtd_device(info->mtd);
+		map_destroy(info->mtd);
+	}
+
+	/* release resources */
+
+	if (info->area) {
+		release_resource(info->area);
+		kfree(info->area);
+	}
+
+	if (info->map.virt != NULL)
+		iounmap(info->map.virt);
+	
+	kfree(info);
+
+	return 0;
+}
+
+/* platflash_probe
+ *
+ * called from device drive system when a device matching our
+ * driver is found.
+*/
+
+static int platflash_probe(struct device *dev)
+{
+	struct platform_device *pd = to_platform_device(dev);
+	struct platflash_info *info;
+	struct platdata_mtd_flash *pdata;
+	struct resource *res;
+	int err = 0;
+	int i;
+
+	dev_dbg(dev, "probe entered\n");
+
+	if (dev->platform_data == NULL) {
+		dev_err(dev, "no platform data supplied\n");
+		err = -ENOENT;
+		goto exit_error;
+	}
+
+	pdata = dev->platform_data;
+
+	if (pdata->chip_probes == 0) {
+		dev_err(dev, "no chip probes specified\n");
+		err = -ENOENT;
+		goto exit_error;
+	}
+	
+	info = kmalloc(sizeof(*info), GFP_KERNEL);
+	if (info == NULL) {
+		dev_err(dev, "no memory for flash info\n");
+		err = -ENOMEM;
+		goto exit_error;
+	}
+
+	memset(info, 0, sizeof(*info));
+	dev_set_drvdata(dev, info);
+
+	info->dev = dev;
+
+	/* get the resource for the memory mapping */
+
+	res = platform_get_resource(pd, IORESOURCE_MEM, 0);
+
+	if (res == NULL) {
+		dev_err(dev, "no memory resource specified\n");
+		err = -ENOENT;
+		goto exit_free;
+	}
+
+	dev_dbg(dev, "got platform resource %p (0x%lx)\n", res, res->start);
+
+	/* setup map parameters */
+
+	info->map.phys = res->start;
+	info->map.size = (res->end - res->start) + 1;
+	info->map.name = pdata->mapname != NULL ? pdata->mapname : pd->name;
+	info->map.bankwidth = pdata->bankwidth;
+
+	/* register our usage of the memory area */
+
+	info->area = request_mem_region(res->start, info->map.size, pd->name);
+	if (info->area == NULL) {
+		dev_err(dev, "failed to request memory region\n");
+		err = -EIO;
+		goto exit_free;
+	}
+
+	/* remap the memory area */
+
+	info->map.virt = ioremap(res->start, info->map.size);
+	dev_dbg(dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
+
+	if (info->map.virt == NULL) {
+		dev_err(dev, "failed to ioremap() region\n");
+		err = -EIO;
+		goto exit_free;
+	}
+
+	simple_map_init(&info->map);
+
+	dev_dbg(dev, "initialised map, probing for mtd\n");
+
+	/* probe for the right mtd map driver */
+	i = 0;
+	while (pdata->chip_probes[i]) {
+		dev_dbg(dev, "probing with %s\n", pdata->chip_probes[i]);
+		info->mtd = do_map_probe(pdata->chip_probes[i], &info->map);
+		i++;
+		if (info->mtd != NULL) 
+			break;
+	}
+	if (info->mtd == NULL) {
+		dev_err(dev, "failed to identify device\n");
+		err = -ENOMEM;
+		goto exit_free;
+	}
+
+	info->mtd->owner = THIS_MODULE;
+
+	/* check to see if there are any available partitions, or wether
+	 * to add this device whole */
+
+#ifdef CONFIG_MTD_PARTITIONS
+	if (pdata->nr_partitions > 0) {
+		if (pdata->partition_probes)
+		{
+			err = parse_mtd_partitions(info->mtd,
+						   pdata->partition_probes,
+						   &info->partitions, 0);
+		}
+		else
+		{
+			err = pdata->nr_partitions;
+			info->partitions = pdata->partitions;
+		}
+
+		if (err > 0) {
+			err = add_mtd_partitions(info->mtd, info->partitions,
+						 err);
+		}
+	}
+#endif /* CONFIG_MTD_PARTITIONS */
+
+	if (add_mtd_device(info->mtd)) {
+		dev_err(dev, "add_mtd_device() failed\n");
+		err = -ENOMEM;
+	}
+	
+	dev_info(dev, "registered mtd device\n");
+	return err;
+
+ exit_free:
+	platflash_remove(dev);
+ exit_error:
+	return err;
+}
+
+/* device driver info */
+
+static struct device_driver platflash_driver = {
+	.name		= "mtd-phys",
+	.bus		= &platform_bus_type,
+	.probe		= platflash_probe,
+	.remove		= platflash_remove,
+};
+
+/* module init/exit */
+
+static int __init platflash_init(void)
+{
+	return driver_register(&platflash_driver);
+}
+
+static void __exit platflash_exit(void)
+{
+	driver_unregister(&platflash_driver);
+}
+
+module_init(platflash_init);
+module_exit(platflash_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mark Brown <broonie@sirena.org.uk>");
+MODULE_DESCRIPTION("MTD platform map driver");
diff -uprN linux-2.6.13/include/linux/mtd/plat-flash.h linux-plat-flash/include/linux/mtd/plat-flash.h
--- linux-2.6.13/include/linux/mtd/plat-flash.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-plat-flash/include/linux/mtd/plat-flash.h	2005-09-08 18:49:28.000000000 +0100
@@ -0,0 +1,29 @@
+/* linux/include/mtd/plat-flash.h
+ *
+ * (c) 2004 Simtec Electronics
+ *	http://www.simtec.co.uk/products/SWLINUX/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * Generic platform device based flash map
+ *
+ * $Id: $
+ *
+ * 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.
+ *
+ */
+
+#ifndef __LINUX_MTD_PLATFLASH_H
+#define __LINUX_MTD_PLATFLASH_H __FILE__
+
+struct platdata_mtd_flash {
+	char			*mapname;
+	char                   **chip_probes;
+	char		       **partition_probes;
+	struct mtd_partition	*partitions;
+	int			 nr_partitions;
+	int			 bankwidth;
+};
+
+#endif /* __LINUX_MTD_PLATRAM_H */

-- 
"You grabbed my hand and we fell into it, like a daydream - or a fever."

[-- Attachment #2: Digital signature --]
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Re: [RFC] Make physmap into a platform device driver...

[Ben Dooks]

On Thu, Dec 29, 2005 at 03:21:38PM -0800, Deepak Saxena wrote:
> 
> I'm working on a system where I want to use the physmap driver
> but the size or buswidth of the flash device might change depending
> on the specific board layout. I want to be able to build a single kernel
> that boots on all boards using this NPU (IXP2350) and with the hardcoded
> approach to buswidth and such, it makes it rather impossible. On ARM
> platforms, we've been using the following data structure to pass
> board-specific flash information to the SOC-specific drivers and I 
> am wondering if it makes sense to move it out of ARM into the generic
> MTD layer and have the physmap driver use it. The physmap driver
> could register itself as a platform driver for "phys-mtd" devices
> and boards would just fill in platform_device structure with the
> appropriate resource window and the needed fields below as the
> platform_data. We may want to trim down the structure to remove 
> ARM-specific fields and let ARM have it's own structure that contains
> the generic structure as a member. Thoughts?

Several people have said they where going to modify the
plat-ram driver I wrote a while ago to support flash...

I think a number of the flash drivers currently in the
mtd system could be rolled into a generic mtd flash driver

-- 
Ben (ben@fluff.org, http://www.fluff.org/)

  'a smiley only costs 4 bytes'

Re: [RFC] Make physmap into a platform device driver...

[Mark Brown]

[Resent without GPG signature since the list software rejected my mail
due to a "suspicious header".]

On Thu, Dec 29, 2005 at 03:21:38PM -0800, Deepak Saxena wrote:

> MTD layer and have the physmap driver use it. The physmap driver
> could register itself as a platform driver for "phys-mtd" devices
> and boards would just fill in platform_device structure with the
> appropriate resource window and the needed fields below as the
> platform_data. We may want to trim down the structure to remove 
> ARM-specific fields and let ARM have it's own structure that contains
> the generic structure as a member. Thoughts?

An alternative approach (which Jason Gunthorpe posted a patch for
recently IIRC) is to add probe support to the plat-ram driver so it can
work with any kind of chip.  I have a patch kicking around doing pretty
much that but also renaming the driver to make it look less strange when
used.

My patch is below - it probably ought to have the re-addition of write
protection methods which I had stripped out since I've got partially
written support for paging in chips and thought the two might end up
related.

diff -uprN linux-2.6.13/drivers/mtd/maps/Kconfig linux-plat-flash/drivers/mtd/maps/Kconfig
--- linux-2.6.13/drivers/mtd/maps/Kconfig	2005-08-29 00:41:01.000000000 +0100
+++ linux-plat-flash/drivers/mtd/maps/Kconfig	2005-09-08 18:51:13.984319480 +0100
@@ -624,5 +624,12 @@ config MTD_PLATRAM
 
 	  This selection automatically selects the map_ram driver.
 
+config MTD_PLATFLASH
+	tristate "Map driver for platform device physically mapped flash"
+	depends on MTD
+	help
+	  Map driver allowing MTD devices which are physically mapped into
+	  the CPU's address space to be enumerated using the platform bus.
+
 endmenu
 
diff -uprN linux-2.6.13/drivers/mtd/maps/Makefile linux-plat-flash/drivers/mtd/maps/Makefile
--- linux-2.6.13/drivers/mtd/maps/Makefile	2005-08-29 00:41:01.000000000 +0100
+++ linux-plat-flash/drivers/mtd/maps/Makefile	2005-09-08 18:51:08.706121888 +0100
@@ -69,4 +69,5 @@ obj-$(CONFIG_MTD_WRSBC8260)	+= wr_sbc82x
 obj-$(CONFIG_MTD_DMV182)	+= dmv182.o
 obj-$(CONFIG_MTD_SHARP_SL)	+= sharpsl-flash.o
 obj-$(CONFIG_MTD_PLATRAM)	+= plat-ram.o
+obj-$(CONFIG_MTD_PLATFLASH)     += plat-flash.o
 obj-$(CONFIG_MTD_OMAP_NOR)	+= omap_nor.o
diff -uprN linux-2.6.13/drivers/mtd/maps/plat-flash.c linux-plat-flash/drivers/mtd/maps/plat-flash.c
--- linux-2.6.13/drivers/mtd/maps/plat-flash.c	1970-01-01 01:00:00.000000000 +0100
+++ linux-plat-flash/drivers/mtd/maps/plat-flash.c	2005-09-08 18:48:56.711188168 +0100
@@ -0,0 +1,270 @@
+/* drivers/mtd/maps/plat-flash.c
+ *
+ * (c) 2004-2005 Simtec Electronics
+ *	http://www.simtec.co.uk/products/SWLINUX/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * Generic platform device based flash mappings.
+ *
+ * $Id: $
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+*/
+
+#include <linux/module.h>
+#include <linux/types.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/string.h>
+#include <linux/ioport.h>
+#include <linux/device.h>
+
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/map.h>
+#include <linux/mtd/partitions.h>
+#include <linux/mtd/plat-flash.h>
+
+#include <asm/io.h>
+
+/* private structure for each mtd platform ram device created */
+
+struct platflash_info {
+	struct device		*dev;
+	struct mtd_info		*mtd;
+	struct map_info		 map;
+	struct mtd_partition	*partitions;
+	struct resource		*area;
+};
+
+/* to_platflash_info()
+ *
+ * device private data to struct platflash_info conversion
+*/
+
+static inline struct platflash_info *to_platflash_info(struct device *dev)
+{
+	return (struct platflash_info *)dev_get_drvdata(dev);
+}
+
+/* platflash_remove
+ *
+ * called to remove the device from the driver's control
+*/
+
+static int platflash_remove(struct device *dev)
+{
+	struct platflash_info *info = to_platflash_info(dev);
+
+	dev_set_drvdata(dev, NULL);
+
+	dev_dbg(dev, "removing device\n");
+
+	if (info == NULL) 
+		return 0;
+
+	if (info->mtd) {
+#ifdef CONFIG_MTD_PARTITIONS
+		if (info->partitions) {
+			del_mtd_partitions(info->mtd);
+			kfree(info->partitions);
+		}
+#endif
+		del_mtd_device(info->mtd);
+		map_destroy(info->mtd);
+	}
+
+	/* release resources */
+
+	if (info->area) {
+		release_resource(info->area);
+		kfree(info->area);
+	}
+
+	if (info->map.virt != NULL)
+		iounmap(info->map.virt);
+	
+	kfree(info);
+
+	return 0;
+}
+
+/* platflash_probe
+ *
+ * called from device drive system when a device matching our
+ * driver is found.
+*/
+
+static int platflash_probe(struct device *dev)
+{
+	struct platform_device *pd = to_platform_device(dev);
+	struct platflash_info *info;
+	struct platdata_mtd_flash *pdata;
+	struct resource *res;
+	int err = 0;
+	int i;
+
+	dev_dbg(dev, "probe entered\n");
+
+	if (dev->platform_data == NULL) {
+		dev_err(dev, "no platform data supplied\n");
+		err = -ENOENT;
+		goto exit_error;
+	}
+
+	pdata = dev->platform_data;
+
+	if (pdata->chip_probes == 0) {
+		dev_err(dev, "no chip probes specified\n");
+		err = -ENOENT;
+		goto exit_error;
+	}
+	
+	info = kmalloc(sizeof(*info), GFP_KERNEL);
+	if (info == NULL) {
+		dev_err(dev, "no memory for flash info\n");
+		err = -ENOMEM;
+		goto exit_error;
+	}
+
+	memset(info, 0, sizeof(*info));
+	dev_set_drvdata(dev, info);
+
+	info->dev = dev;
+
+	/* get the resource for the memory mapping */
+
+	res = platform_get_resource(pd, IORESOURCE_MEM, 0);
+
+	if (res == NULL) {
+		dev_err(dev, "no memory resource specified\n");
+		err = -ENOENT;
+		goto exit_free;
+	}
+
+	dev_dbg(dev, "got platform resource %p (0x%lx)\n", res, res->start);
+
+	/* setup map parameters */
+
+	info->map.phys = res->start;
+	info->map.size = (res->end - res->start) + 1;
+	info->map.name = pdata->mapname != NULL ? pdata->mapname : pd->name;
+	info->map.bankwidth = pdata->bankwidth;
+
+	/* register our usage of the memory area */
+
+	info->area = request_mem_region(res->start, info->map.size, pd->name);
+	if (info->area == NULL) {
+		dev_err(dev, "failed to request memory region\n");
+		err = -EIO;
+		goto exit_free;
+	}
+
+	/* remap the memory area */
+
+	info->map.virt = ioremap(res->start, info->map.size);
+	dev_dbg(dev, "virt %p, %lu bytes\n", info->map.virt, info->map.size);
+
+	if (info->map.virt == NULL) {
+		dev_err(dev, "failed to ioremap() region\n");
+		err = -EIO;
+		goto exit_free;
+	}
+
+	simple_map_init(&info->map);
+
+	dev_dbg(dev, "initialised map, probing for mtd\n");
+
+	/* probe for the right mtd map driver */
+	i = 0;
+	while (pdata->chip_probes[i]) {
+		dev_dbg(dev, "probing with %s\n", pdata->chip_probes[i]);
+		info->mtd = do_map_probe(pdata->chip_probes[i], &info->map);
+		i++;
+		if (info->mtd != NULL) 
+			break;
+	}
+	if (info->mtd == NULL) {
+		dev_err(dev, "failed to identify device\n");
+		err = -ENOMEM;
+		goto exit_free;
+	}
+
+	info->mtd->owner = THIS_MODULE;
+
+	/* check to see if there are any available partitions, or wether
+	 * to add this device whole */
+
+#ifdef CONFIG_MTD_PARTITIONS
+	if (pdata->nr_partitions > 0) {
+		if (pdata->partition_probes)
+		{
+			err = parse_mtd_partitions(info->mtd,
+						   pdata->partition_probes,
+						   &info->partitions, 0);
+		}
+		else
+		{
+			err = pdata->nr_partitions;
+			info->partitions = pdata->partitions;
+		}
+
+		if (err > 0) {
+			err = add_mtd_partitions(info->mtd, info->partitions,
+						 err);
+		}
+	}
+#endif /* CONFIG_MTD_PARTITIONS */
+
+	if (add_mtd_device(info->mtd)) {
+		dev_err(dev, "add_mtd_device() failed\n");
+		err = -ENOMEM;
+	}
+	
+	dev_info(dev, "registered mtd device\n");
+	return err;
+
+ exit_free:
+	platflash_remove(dev);
+ exit_error:
+	return err;
+}
+
+/* device driver info */
+
+static struct device_driver platflash_driver = {
+	.name		= "mtd-phys",
+	.bus		= &platform_bus_type,
+	.probe		= platflash_probe,
+	.remove		= platflash_remove,
+};
+
+/* module init/exit */
+
+static int __init platflash_init(void)
+{
+	return driver_register(&platflash_driver);
+}
+
+static void __exit platflash_exit(void)
+{
+	driver_unregister(&platflash_driver);
+}
+
+module_init(platflash_init);
+module_exit(platflash_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Mark Brown <broonie@sirena.org.uk>");
+MODULE_DESCRIPTION("MTD platform map driver");
diff -uprN linux-2.6.13/include/linux/mtd/plat-flash.h linux-plat-flash/include/linux/mtd/plat-flash.h
--- linux-2.6.13/include/linux/mtd/plat-flash.h	1970-01-01 01:00:00.000000000 +0100
+++ linux-plat-flash/include/linux/mtd/plat-flash.h	2005-09-08 18:49:28.000000000 +0100
@@ -0,0 +1,29 @@
+/* linux/include/mtd/plat-flash.h
+ *
+ * (c) 2004 Simtec Electronics
+ *	http://www.simtec.co.uk/products/SWLINUX/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * Generic platform device based flash map
+ *
+ * $Id: $
+ *
+ * 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.
+ *
+ */
+
+#ifndef __LINUX_MTD_PLATFLASH_H
+#define __LINUX_MTD_PLATFLASH_H __FILE__
+
+struct platdata_mtd_flash {
+	char			*mapname;
+	char                   **chip_probes;
+	char		       **partition_probes;
+	struct mtd_partition	*partitions;
+	int			 nr_partitions;
+	int			 bankwidth;
+};
+
+#endif /* __LINUX_MTD_PLATRAM_H */

-- 
"You grabbed my hand and we fell into it, like a daydream - or a fever."

Re: [RFC] Make physmap into a platform device driver...

[Jared Hulbert]

> My patch is below - it probably ought to have the re-addition of write
> protection methods which I had stripped out since I've got partially
> written support for paging in chips and thought the two might end up
> related.

One thing I would like to see is the addition of something like:

<code>
       info->map.cached = ioremap_cached(res->start, info->map.size);
       dev_dbg(dev, "cached %p, %lu bytes\n", info->map.cached, info->map.size);

       if (info->map.cached == NULL) {
               dev_err(dev, "failed to ioremap_cached() region\n");
               err = -EIO;
               goto exit_free;
       }
</code>

The problem is how do we populate info->map.inval_cache?

drivers/mtd/maps/mainstone-flash.c does it as follows.

<code>
static void mainstone_map_inval_cache(struct map_info *map, unsigned long from,
                                       ssize_t len)
{
         consistent_sync((char *)map->cached + from, len, DMA_FROM_DEVICE);
}

 static struct map_info mainstone_maps[2] = { {
         .size =         WINDOW_SIZE,
         .phys =         PXA_CS0_PHYS,
         .inval_cache =  mainstone_map_inval_cache,
 }, {
         .size =         WINDOW_SIZE,
         .phys =         PXA_CS1_PHYS,
         .inval_cache =  mainstone_map_inval_cache,
} };
</code>

Is the consistent_sync() and ioremap_cached() generic enough to
include in a platflash.c?