* [PATCH] mtd: physmap_of: Add "map-indirect" DT property
@ 2012-07-03 8:26 Stefan Roese
2012-07-07 7:16 ` Stephan Gatzka
` (2 more replies)
0 siblings, 3 replies; 7+ messages in thread
From: Stefan Roese @ 2012-07-03 8:26 UTC (permalink / raw)
To: linux-mtd; +Cc: Albrecht Dress, Anatolij Gustschin, Stephan Gatzka
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 "map-indirect", 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>
---
Documentation/devicetree/bindings/mtd/mtd-physmap.txt | 7 +++++++
drivers/mtd/maps/physmap_of.c | 14 ++++++++++++++
2 files changed, 21 insertions(+)
diff --git a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt
index a63c2bd7..97a7245 100644
--- a/Documentation/devicetree/bindings/mtd/mtd-physmap.txt
+++ b/Documentation/devicetree/bindings/mtd/mtd-physmap.txt
@@ -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.
+ - map-indirect: 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 "map-indirect", 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:
diff --git a/drivers/mtd/maps/physmap_of.c b/drivers/mtd/maps/physmap_of.c
index 2e6fb68..a96011d 100644
--- a/drivers/mtd/maps/physmap_of.c
+++ b/drivers/mtd/maps/physmap_of.c
@@ -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, "map-indirect");
+
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);
--
1.7.11.1
^ permalink raw reply related [flat|nested] 7+ messages in thread
* Re: [PATCH] mtd: physmap_of: Add "map-indirect" DT property
2012-07-03 8:26 [PATCH] mtd: physmap_of: Add "map-indirect" DT property Stefan Roese
@ 2012-07-07 7:16 ` Stephan Gatzka
2012-07-16 20:41 ` David Woodhouse
2012-07-16 7:43 ` Anatolij Gustschin
2012-07-16 15:03 ` Artem Bityutskiy
2 siblings, 1 reply; 7+ messages in thread
From: Stephan Gatzka @ 2012-07-07 7:16 UTC (permalink / raw)
To: Stefan Roese
Cc: Albrecht Dress, Anatolij Gustschin, linux-mtd, Stephan Gatzka
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Hello all,
this patch works very well for us (of course, because Stefan made it for
us). Are there any concerns against it? Probably against introducing a
new DT property? Of course we can make this fix much more MPC5200
specific but this will result in largely copying physmap_of.c and some
additional code for access routines and Kconfig.
I'm wondering a bit about this silence because I consider this LPB issue
a major concern for the MPC5200.
Regards,
Stephan
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mtd: physmap_of: Add "map-indirect" DT property
2012-07-03 8:26 [PATCH] mtd: physmap_of: Add "map-indirect" DT property Stefan Roese
2012-07-07 7:16 ` Stephan Gatzka
@ 2012-07-16 7:43 ` Anatolij Gustschin
2012-07-16 15:03 ` Artem Bityutskiy
2 siblings, 0 replies; 7+ messages in thread
From: Anatolij Gustschin @ 2012-07-16 7:43 UTC (permalink / raw)
To: Stefan Roese; +Cc: Albrecht Dress, linux-mtd, Stephan Gatzka
Hi Stefan,
On Tue, 3 Jul 2012 10:26:31 +0200
Stefan Roese <sr@denx.de> wrote:
> 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 "map-indirect", 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>
> ---
> Documentation/devicetree/bindings/mtd/mtd-physmap.txt | 7 +++++++
> drivers/mtd/maps/physmap_of.c | 14 ++++++++++++++
> 2 files changed, 21 insertions(+)
The patch looks good, so
Acked-by: Anatolij Gustschin <agust@denx.de>
Thanks,
Anatolij
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mtd: physmap_of: Add "map-indirect" DT property
2012-07-03 8:26 [PATCH] mtd: physmap_of: Add "map-indirect" DT property Stefan Roese
2012-07-07 7:16 ` Stephan Gatzka
2012-07-16 7:43 ` Anatolij Gustschin
@ 2012-07-16 15:03 ` Artem Bityutskiy
2 siblings, 0 replies; 7+ messages in thread
From: Artem Bityutskiy @ 2012-07-16 15:03 UTC (permalink / raw)
To: Stefan Roese
Cc: Albrecht Dress, Anatolij Gustschin, linux-mtd, Stephan Gatzka
[-- Attachment #1: Type: text/plain, Size: 447 bytes --]
On Tue, 2012-07-03 at 10:26 +0200, Stefan Roese wrote:
> 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 "map-indirect", the flash will not be exposed directly
> to the MTD users (e.g. JFFS2) any more.
Pushed to l2-mtd.git, thanks!
--
Best Regards,
Artem Bityutskiy
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mtd: physmap_of: Add "map-indirect" DT property
2012-07-07 7:16 ` Stephan Gatzka
@ 2012-07-16 20:41 ` David Woodhouse
2012-07-17 9:56 ` Stefan Roese
0 siblings, 1 reply; 7+ messages in thread
From: David Woodhouse @ 2012-07-16 20:41 UTC (permalink / raw)
To: stephan
Cc: Albrecht Dress, Stefan Roese, linux-mtd, Anatolij Gustschin,
Stephan Gatzka
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On Sat, 2012-07-07 at 09:16 +0200, Stephan Gatzka wrote:
> this patch works very well for us (of course, because Stefan made it for
> us). Are there any concerns against it? Probably against introducing a
> new DT property? Of course we can make this fix much more MPC5200
> specific but this will result in largely copying physmap_of.c and some
> additional code for access routines and Kconfig.
I don't much like the "map-indirect" name. If it's actually unaligned
access, or non-word-sized access, that's forbidden, then that's what the
DT property should be.
The term "map-indirect" is more a description of how the software
currently behaves... which is exactly that DT bindings *shouldn't* be.
--
dwmw2
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^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mtd: physmap_of: Add "map-indirect" DT property
2012-07-16 20:41 ` David Woodhouse
@ 2012-07-17 9:56 ` Stefan Roese
2012-07-18 6:26 ` Artem Bityutskiy
0 siblings, 1 reply; 7+ messages in thread
From: Stefan Roese @ 2012-07-17 9:56 UTC (permalink / raw)
To: David Woodhouse
Cc: Albrecht Dress, Anatolij Gustschin, linux-mtd, stephan, Stephan Gatzka
On Monday 16 July 2012 22:41:52 David Woodhouse wrote:
> On Sat, 2012-07-07 at 09:16 +0200, Stephan Gatzka wrote:
> > this patch works very well for us (of course, because Stefan made it for
> > us). Are there any concerns against it? Probably against introducing a
> > new DT property? Of course we can make this fix much more MPC5200
> > specific but this will result in largely copying physmap_of.c and some
> > additional code for access routines and Kconfig.
>
> I don't much like the "map-indirect" name. If it's actually unaligned
> access, or non-word-sized access, that's forbidden, then that's what the
> DT property should be.
>
> The term "map-indirect" is more a description of how the software
> currently behaves... which is exactly that DT bindings *shouldn't* be.
Okay. I've chosen "map-indirect" because it might be used by other platforms
as well, perhaps because of different reasons (so not restricting this to the
unaligned access problem of the MPC5200). But I have no strong feelings here,
so I can prepare a new patch version with a different name.
How about "no-unaligned-direct-access"? Pretty long though. Any other
suggestions here?
Thanks,
Stefan
^ permalink raw reply [flat|nested] 7+ messages in thread
* Re: [PATCH] mtd: physmap_of: Add "map-indirect" DT property
2012-07-17 9:56 ` Stefan Roese
@ 2012-07-18 6:26 ` Artem Bityutskiy
0 siblings, 0 replies; 7+ messages in thread
From: Artem Bityutskiy @ 2012-07-18 6:26 UTC (permalink / raw)
To: Stefan Roese
Cc: stephan, Albrecht Dress, linux-mtd, Anatolij Gustschin,
David Woodhouse, Stephan Gatzka
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On Tue, 2012-07-17 at 11:56 +0200, Stefan Roese wrote:
> How about "no-unaligned-direct-access"? Pretty long though. Any other
> suggestions here?
FYI, I am dropping this patch from l2-mtd.git.
--
Best Regards,
Artem Bityutskiy
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^ permalink raw reply [flat|nested] 7+ messages in thread
end of thread, other threads:[~2012-07-18 6:32 UTC | newest]
Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2012-07-03 8:26 [PATCH] mtd: physmap_of: Add "map-indirect" DT property Stefan Roese
2012-07-07 7:16 ` Stephan Gatzka
2012-07-16 20:41 ` David Woodhouse
2012-07-17 9:56 ` Stefan Roese
2012-07-18 6:26 ` Artem Bityutskiy
2012-07-16 7:43 ` Anatolij Gustschin
2012-07-16 15:03 ` Artem Bityutskiy
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