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Commit 402d3265 authored by David Howells's avatar David Howells Committed by David Woodhouse
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NOMMU: Present backing device capabilities for MTD chardevs 



Present backing device capabilities for MTD character device files to allow
NOMMU mmap to do direct mapping where possible.

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarBernd Schmidt <bernd.schmidt@analog.com>
Signed-off-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
parent 9ce96908

drivers/mtd/Makefile

+1 −1
Original line number Diff line number Diff line
@@ -4,7 +4,7 @@ 


# Core functionality.

obj-$(CONFIG_MTD)		+= mtd.o

mtd-y				:= mtdcore.o mtdsuper.o

mtd-y				:= mtdcore.o mtdsuper.o mtdbdi.o

mtd-$(CONFIG_MTD_PARTITIONS)	+= mtdpart.o



obj-$(CONFIG_MTD_CONCAT)	+= mtdconcat.o

drivers/mtd/chips/map_ram.c

+17 −0
Original line number Diff line number Diff line
@@ -21,6 +21,8 @@ static int mapram_write (struct mtd_info *, loff_t, size_t, size_t *, const u_ch 
static int mapram_erase (struct mtd_info *, struct erase_info *);

static void mapram_nop (struct mtd_info *);

static struct mtd_info *map_ram_probe(struct map_info *map);

static unsigned long mapram_unmapped_area(struct mtd_info *, unsigned long,

					  unsigned long, unsigned long);





static struct mtd_chip_driver mapram_chipdrv = {
@@ -64,6 +66,7 @@ static struct mtd_info *map_ram_probe(struct map_info *map) 
	mtd->type = MTD_RAM;

	mtd->size = map->size;

	mtd->erase = mapram_erase;

	mtd->get_unmapped_area = mapram_unmapped_area;

	mtd->read = mapram_read;

	mtd->write = mapram_write;

	mtd->sync = mapram_nop;
@@ -79,6 +82,20 @@ static struct mtd_info *map_ram_probe(struct map_info *map) 
}





/*

 * Allow NOMMU mmap() to directly map the device (if not NULL)

 * - return the address to which the offset maps

 * - return -ENOSYS to indicate refusal to do the mapping

 */

static unsigned long mapram_unmapped_area(struct mtd_info *mtd,

					  unsigned long len,

					  unsigned long offset,

					  unsigned long flags)

{

	struct map_info *map = mtd->priv;

	return (unsigned long) map->virt + offset;

}



static int mapram_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)

{

	struct map_info *map = mtd->priv;

drivers/mtd/chips/map_rom.c

+17 −0
Original line number Diff line number Diff line
@@ -20,6 +20,8 @@ static int maprom_write (struct mtd_info *, loff_t, size_t, size_t *, const u_ch 
static void maprom_nop (struct mtd_info *);

static struct mtd_info *map_rom_probe(struct map_info *map);

static int maprom_erase (struct mtd_info *mtd, struct erase_info *info);

static unsigned long maprom_unmapped_area(struct mtd_info *, unsigned long,

					  unsigned long, unsigned long);



static struct mtd_chip_driver maprom_chipdrv = {

	.probe	= map_rom_probe,
@@ -40,6 +42,7 @@ static struct mtd_info *map_rom_probe(struct map_info *map) 
	mtd->name = map->name;

	mtd->type = MTD_ROM;

	mtd->size = map->size;

	mtd->get_unmapped_area = maprom_unmapped_area;

	mtd->read = maprom_read;

	mtd->write = maprom_write;

	mtd->sync = maprom_nop;
@@ -53,6 +56,20 @@ static struct mtd_info *map_rom_probe(struct map_info *map) 
}





/*

 * Allow NOMMU mmap() to directly map the device (if not NULL)

 * - return the address to which the offset maps

 * - return -ENOSYS to indicate refusal to do the mapping

 */

static unsigned long maprom_unmapped_area(struct mtd_info *mtd,

					  unsigned long len,

					  unsigned long offset,

					  unsigned long flags)

{

	struct map_info *map = mtd->priv;

	return (unsigned long) map->virt + offset;

}



static int maprom_read (struct mtd_info *mtd, loff_t from, size_t len, size_t *retlen, u_char *buf)

{

	struct map_info *map = mtd->priv;

drivers/mtd/devices/mtdram.c

+14 −0
Original line number Diff line number Diff line
@@ -65,6 +65,19 @@ static void ram_unpoint(struct mtd_info *mtd, loff_t from, size_t len) 
{

}



/*

 * Allow NOMMU mmap() to directly map the device (if not NULL)

 * - return the address to which the offset maps

 * - return -ENOSYS to indicate refusal to do the mapping

 */

static unsigned long ram_get_unmapped_area(struct mtd_info *mtd,

					   unsigned long len,

					   unsigned long offset,

					   unsigned long flags)

{

	return (unsigned long) mtd->priv + offset;

}



static int ram_read(struct mtd_info *mtd, loff_t from, size_t len,

		size_t *retlen, u_char *buf)

{
@@ -116,6 +129,7 @@ int mtdram_init_device(struct mtd_info *mtd, void *mapped_address, 
	mtd->erase = ram_erase;

	mtd->point = ram_point;

	mtd->unpoint = ram_unpoint;

	mtd->get_unmapped_area = ram_get_unmapped_area;

	mtd->read = ram_read;

	mtd->write = ram_write;

drivers/mtd/internal.h

0 → 100644
+17 −0
Original line number Diff line number Diff line 
/* Internal MTD definitions

 *

 * Copyright © 2006 Red Hat, Inc. All Rights Reserved.

 * Written by David Howells (dhowells@redhat.com)

 *

 * 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.

 */



/*

 * mtdbdi.c

 */

extern struct backing_dev_info mtd_bdi_unmappable;

extern struct backing_dev_info mtd_bdi_ro_mappable;

extern struct backing_dev_info mtd_bdi_rw_mappable;