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mtd: physmap_of: Add "no-unaligned-direct-access" DT property

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On some platforms (e.g. MPC5200) a direct 1:1 mapping may cause
problems with JFFS2 usage, as the local bus (LPB) doesn't support
unaligned accesses as implemented in the JFFS2 code via memcpy().
By defining "no-unaligned-direct-access", the flash will not be
exposed directly to the MTD users (e.g. JFFS2) any more.

Signed-off-by: Stefan Roese <sr@denx.de>
Signed-off-by: Artem Bityutskiy <artem.bityutskiy@linux.intel.com>
Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
This commit is contained in:
Stefan Roese 2012-08-17 15:22:32 +02:00 committed by David Woodhouse
parent e1ed147fd4
commit d0788ce492
2 changed files with 21 additions and 0 deletions
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7
Documentation/devicetree/bindings/mtd/mtd-physmap.txt
View File

@ -16,6 +16,13 @@ file systems on embedded devices.
- #address-cells, #size-cells : Must be present if the device has
sub-nodes representing partitions (see below). In this case
both #address-cells and #size-cells must be equal to 1.
- no-unaligned-direct-access: boolean to disable the default direct
mapping of the flash.
On some platforms (e.g. MPC5200) a direct 1:1 mapping may cause
problems with JFFS2 usage, as the local bus (LPB) doesn't support
unaligned accesses as implemented in the JFFS2 code via memcpy().
By defining "no-unaligned-direct-access", the flash will not be
exposed directly to the MTD users (e.g. JFFS2) any more.
For JEDEC compatible devices, the following additional properties
are defined:

14
drivers/mtd/maps/physmap_of.c
View File

@ -169,6 +169,7 @@ static int __devinit of_flash_probe(struct platform_device *dev)
struct mtd_info **mtd_list = NULL;
resource_size_t res_size;
struct mtd_part_parser_data ppdata;
bool map_indirect;
match = of_match_device(of_flash_match, &dev->dev);
if (!match)
@ -192,6 +193,8 @@ static int __devinit of_flash_probe(struct platform_device *dev)
}
count /= reg_tuple_size;
map_indirect = of_property_read_bool(dp, "no-unaligned-direct-access");
err = -ENOMEM;
info = kzalloc(sizeof(struct of_flash) +
sizeof(struct of_flash_list) * count, GFP_KERNEL);
@ -247,6 +250,17 @@ static int __devinit of_flash_probe(struct platform_device *dev)
simple_map_init(&info->list[i].map);
/*
* On some platforms (e.g. MPC5200) a direct 1:1 mapping
* may cause problems with JFFS2 usage, as the local bus (LPB)
* doesn't support unaligned accesses as implemented in the
* JFFS2 code via memcpy(). By setting NO_XIP, the
* flash will not be exposed directly to the MTD users
* (e.g. JFFS2) any more.
*/
if (map_indirect)
info->list[i].map.phys = NO_XIP;
if (probe_type) {
info->list[i].mtd = do_map_probe(probe_type,
&info->list[i].map);