mtd: uclinux: support ROM and allow passing the base address

This allows to put the filesystem at a defined address in ROM allowing
to save more precious RAM.

I think it's safe to default to ROM because the intention of using the
uclinux map is to use a romfs and so mtd-ram doesn't give you anything
that mtd-rom doesn't.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Greg Ungerer <gerg@uclinux.org>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>

2 files changed, 20 insertions, 6 deletions

diff --git a/drivers/mtd/maps/Kconfig b/drivers/mtd/maps/Kconfig
index 62ba82c396c2..3ed17c4d4358 100644
--- a/drivers/mtd/maps/Kconfig
+++ b/drivers/mtd/maps/Kconfig
@@ -429,7 +429,7 @@ config MTD_GPIO_ADDR
 
 config MTD_UCLINUX
         bool "Generic uClinux RAM/ROM filesystem support"
-        depends on MTD_RAM=y && (!MMU || COLDFIRE)
+        depends on (MTD_RAM=y || MTD_ROM=y) && (!MMU || COLDFIRE)
         help
           Map driver to support image based filesystems for uClinux.
 
diff --git a/drivers/mtd/maps/uclinux.c b/drivers/mtd/maps/uclinux.c
index 299bf88a6f41..f56d0aa4404b 100644
--- a/drivers/mtd/maps/uclinux.c
+++ b/drivers/mtd/maps/uclinux.c
@@ -23,12 +23,20 @@
 
 /****************************************************************************/
 
+#ifdef CONFIG_MTD_ROM
+#define MAP_NAME "rom"
+#else
+#define MAP_NAME "ram"
+#endif
+
 struct map_info uclinux_ram_map = {
-        .name = "RAM",
-        .phys = (unsigned long)__bss_stop,
+        .name = MAP_NAME,
         .size = 0,
 };
 
+static unsigned long physaddr = -1;
+module_param(physaddr, ulong, S_IRUGO);
+
 static struct mtd_info *uclinux_ram_mtdinfo;
 
 /****************************************************************************/
@@ -60,11 +68,17 @@ static int __init uclinux_mtd_init(void)
         struct map_info *mapp;
 
         mapp = &uclinux_ram_map;
+
+        if (physaddr == -1)
+                mapp->phys = (resource_size_t)__bss_stop;
+        else
+                mapp->phys = physaddr;
+
         if (!mapp->size)
                 mapp->size = PAGE_ALIGN(ntohl(*((unsigned long *)(mapp->phys + 8))));
         mapp->bankwidth = 4;
 
-        printk("uclinux[mtd]: RAM probe address=0x%x size=0x%x\n",
+        printk("uclinux[mtd]: probe address=0x%x size=0x%x\n",
                 (int) mapp->phys, (int) mapp->size);
 
         /*
@@ -82,7 +96,7 @@ static int __init uclinux_mtd_init(void)
 
         simple_map_init(mapp);
 
-        mtd = do_map_probe("map_ram", mapp);
+        mtd = do_map_probe("map_" MAP_NAME, mapp);
         if (!mtd) {
                 printk("uclinux[mtd]: failed to find a mapping?\n");
                 return(-ENXIO);
@@ -118,6 +132,6 @@ module_exit(uclinux_mtd_cleanup);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Greg Ungerer <gerg@snapgear.com>");
-MODULE_DESCRIPTION("Generic RAM based MTD for uClinux");
+MODULE_DESCRIPTION("Generic MTD for uClinux");
 
 /****************************************************************************/