[RFC] Make physmap into a platform device driver...
Mark Brown
broonie at sirena.org.uk
Sat Dec 31 07:33:41 EST 2005
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 at 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 at 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 at 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."
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