[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>

1 files changed, 286 insertions, 0 deletions

diff --git a/drivers/mtd/maps/plat-ram.c b/drivers/mtd/maps/plat-ram.c
new file mode 100644
index 000000000000..808f94346add
--- /dev/null
+++ b/drivers/mtd/maps/plat-ram.c
@@ -0,0 +1,286 @@
+/* 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");