mtd: physmap_of: Add "no-unaligned-direct-access" DT property
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>
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@ -16,6 +16,13 @@ file systems on embedded devices.
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- #address-cells, #size-cells : Must be present if the device has
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sub-nodes representing partitions (see below). In this case
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both #address-cells and #size-cells must be equal to 1.
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- no-unaligned-direct-access: boolean to disable the default direct
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mapping of the flash.
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On some platforms (e.g. MPC5200) a direct 1:1 mapping may cause
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problems with JFFS2 usage, as the local bus (LPB) doesn't support
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unaligned accesses as implemented in the JFFS2 code via memcpy().
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By defining "no-unaligned-direct-access", the flash will not be
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exposed directly to the MTD users (e.g. JFFS2) any more.
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For JEDEC compatible devices, the following additional properties
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are defined:
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@ -169,6 +169,7 @@ static int __devinit of_flash_probe(struct platform_device *dev)
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struct mtd_info **mtd_list = NULL;
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resource_size_t res_size;
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struct mtd_part_parser_data ppdata;
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bool map_indirect;
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match = of_match_device(of_flash_match, &dev->dev);
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if (!match)
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@ -192,6 +193,8 @@ static int __devinit of_flash_probe(struct platform_device *dev)
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}
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count /= reg_tuple_size;
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map_indirect = of_property_read_bool(dp, "no-unaligned-direct-access");
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err = -ENOMEM;
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info = kzalloc(sizeof(struct of_flash) +
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sizeof(struct of_flash_list) * count, GFP_KERNEL);
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@ -247,6 +250,17 @@ static int __devinit of_flash_probe(struct platform_device *dev)
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simple_map_init(&info->list[i].map);
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/*
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* On some platforms (e.g. MPC5200) a direct 1:1 mapping
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* may cause problems with JFFS2 usage, as the local bus (LPB)
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* doesn't support unaligned accesses as implemented in the
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* JFFS2 code via memcpy(). By setting NO_XIP, the
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* flash will not be exposed directly to the MTD users
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* (e.g. JFFS2) any more.
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*/
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if (map_indirect)
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info->list[i].map.phys = NO_XIP;
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if (probe_type) {
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info->list[i].mtd = do_map_probe(probe_type,
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&info->list[i].map);
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