[MTD] Platform RAM Driver

Driver for generic RAM blocks which are exported by an platform_device
from the device driver system.
Signed-off-by: Ben Dooks <ben@simtec.co.uk>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

drivers/mtd/maps/Kconfig

 # drivers/mtd/maps/Kconfig
-# $Id: Kconfig,v 1.42 2005/01/05 16:59:50 dwmw2 Exp $
+# $Id: Kconfig,v 1.43 2005/01/24 00:35:21 bjd Exp $
 
 menu "Mapping drivers for chip access"
 	depends on MTD!=n
@@ -659,5 +659,15 @@ config MTD_SHARP_SL
 	help
 	  This enables access to the flash chip on the Sharp SL Series of PDAs.
 
+config MTD_PLATRAM
+	tristate "Map driver for platfrom device RAM (mtd-ram)"
+	depends on MTD
+	select MTD_RAM
+	help
+	  Map driver for RAM areas described via the platform device
+	  system.
+
+	  This selection automatically selects the map_ram driver.
+
 endmenu
 

drivers/mtd/maps/Makefile

 #
 # linux/drivers/maps/Makefile
 #
-# $Id: Makefile.common,v 1.23 2005/01/05 17:06:36 dwmw2 Exp $
+# $Id: Makefile.common,v 1.24 2005/01/24 00:35:21 bjd Exp $
 
 ifeq ($(CONFIG_MTD_COMPLEX_MAPPINGS),y)
 obj-$(CONFIG_MTD)		+= map_funcs.o
@@ -71,3 +71,4 @@ obj-$(CONFIG_MTD_IXP2000)	+= ixp2000.o
 obj-$(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

drivers/mtd/maps/plat-ram.c

+/* drivers/mtd/maps/plat-ram.c
+ *
+ * (c) 2004-2005 Simtec Electronics
+ *	http://www.simtec.co.uk/products/SWLINUX/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * Generic platfrom device based RAM map
+ *
+ * $Id: plat-ram.c,v 1.1 2005/01/24 00:37:02 bjd Exp $
+ *
+ * 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
+*/
+
+#define DEBUG
+
+#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-ram.h>
+
+#include <asm/io.h>
+
+/* private structure for each mtd platform ram device created */
+
+struct platram_info {
+	struct device		*dev;
+	struct mtd_info		*mtd;
+	struct map_info		 map;
+	struct mtd_partition	*partitions;
+	struct resource		*area;
+	struct platdata_mtd_ram	*pdata;
+};
+
+/* to_platram_info()
+ *
+ * device private data to struct platram_info conversion
+*/
+
+static inline struct platram_info *to_platram_info(struct device *dev)
+{
+	return (struct platram_info *)dev_get_drvdata(dev);
+}
+
+/* platram_setrw
+ *
+ * call the platform device's set rw/ro control
+ *
+ * to = 0 => read-only
+ *    = 1 => read-write
+*/
+
+static inline void platram_setrw(struct platram_info *info, int to)
+{
+	if (info->pdata == NULL)
+		return;
+
+	if (info->pdata->set_rw != NULL)
+		(info->pdata->set_rw)(info->dev, to);
+}
+
+/* platram_remove
+ *
+ * called to remove the device from the driver's control
+*/
+
+static int platram_remove(struct device *dev)
+{
+	struct platram_info *info = to_platram_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);
+	}
+
+	/* ensure ram is left read-only */
+
+	platram_setrw(info, PLATRAM_RO);
+
+	/* 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;
+}
+
+/* platram_probe
+ *
+ * called from device drive system when a device matching our
+ * driver is found.
+*/
+
+static int platram_probe(struct device *dev)
+{
+	struct platform_device *pd = to_platform_device(dev);
+	struct platdata_mtd_ram	*pdata;
+	struct platram_info *info;
+	struct resource *res;
+	int err = 0;
+
+	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;
+
+	info = kmalloc(sizeof(*info), GFP_KERNEL);
+	if (info == NULL) {
+		dev_err(dev, "no memory for flash info\n");
+		err = -ENOMEM;
+		goto exit_error;
+	}
+
+	memzero(info, sizeof(*info));
+	dev_set_drvdata(dev, info);
+
+	info->dev = dev;
+	info->pdata = pdata;
+
+	/* 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, %d 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;
+	}
+
+	{
+		unsigned int *p = (unsigned int *)info->map.virt;
+		printk("%08x %08x %08x %08x\n",
+		       readl(p), readl(p+1), readl(p+2), readl(p+3));
+	}
+
+	simple_map_init(&info->map);
+
+	dev_dbg(dev, "initialised map, probing for mtd\n");
+
+	/* probe for the right mtd map driver */
+
+	info->mtd = do_map_probe("map_ram" , &info->map);
+	if (info->mtd == NULL) {
+		dev_err(dev, "failed to probe for map_ram\n");
+		err = -ENOMEM;
+		goto exit_free;
+	}
+
+	info->mtd->owner = THIS_MODULE;
+
+	platram_setrw(info, PLATRAM_RW);
+
+	/* 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) {
+		const char **probes = { NULL };
+
+		if (pdata->probes)
+			probes = (const char **)pdata->probes;
+
+		err = parse_mtd_partitions(info->mtd, probes,
+					   &info->partitions, 0);
+		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:
+	platram_remove(dev);
+ exit_error:
+	return err;
+}
+
+/* device driver info */
+
+static struct device_driver platram_driver = {
+	.name		= "mtd-ram",
+	.bus		= &platform_bus_type,
+	.probe		= platram_probe,
+	.remove		= platram_remove,
+};
+
+/* module init/exit */
+
+static int __init platram_init(void)
+{
+	printk("Generic platform RAM MTD, (c) 2004 Simtec Electronics\n");
+	return driver_register(&platram_driver);
+}
+
+static void __exit platram_exit(void)
+{
+	driver_unregister(&platram_driver);
+}
+
+module_init(platram_init);
+module_exit(platram_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
+MODULE_DESCRIPTION("MTD platform RAM map driver");

include/linux/mtd/plat-ram.h

+/* linux/include/mtd/plat-ram.h
+ *
+ * (c) 2004 Simtec Electronics
+ *	http://www.simtec.co.uk/products/SWLINUX/
+ *	Ben Dooks <ben@simtec.co.uk>
+ *
+ * Generic platform device based RAM map
+ *
+ * $Id: plat-ram.h,v 1.2 2005/01/24 00:37:40 bjd Exp $
+ *
+ * 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_PLATRAM_H
+#define __LINUX_MTD_PLATRAM_H __FILE__
+
+#define PLATRAM_RO (0)
+#define PLATRAM_RW (1)
+
+struct platdata_mtd_ram {
+	char			*mapname;
+	char		       **probes;
+	struct mtd_partition	*partitions;
+	int			 nr_partitions;
+	int			 bankwidth;
+
+	/* control callbacks */
+
+	void	(*set_rw)(struct device *dev, int to);
+};
+
+#endif /* __LINUX_MTD_PLATRAM_H */