@@ -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:
@@ -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);
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> Cc: Stephan Gatzka <Stephan.Gatzka@hbm.com> Cc: Anatolij Gustschin <agust@denx.de> Cc: Albrecht Dress <albrecht.dress@arcor.de> Cc: Artem Bityutskiy <dedekind1@gmail.com> Cc: David Woodhouse <dwmw2@infradead.org> --- v2: - Changed "map-indirect" to "no-unaligned-direct-access" because of David's comments. Documentation/devicetree/bindings/mtd/mtd-physmap.txt | 7 +++++++ drivers/mtd/maps/physmap_of.c | 14 ++++++++++++++ 2 files changed, 21 insertions(+)