* boot partition access at HS200 speed in eMMC
@ 2018-08-02 9:44 ` Faiz Abbas
0 siblings, 0 replies; 4+ messages in thread
From: Faiz Abbas @ 2018-08-02 9:44 UTC (permalink / raw)
To: U-Boot Mailing List, linux-mmc; +Cc: Ulf Hansson
Hi Everyone,
After the following patch from JJ, U-boot shifts to a lower speed mode
from HS200 when accessing a boot partition.
01298da31d mmc: Change mode when switching to a boot partition
I have looked through the JESD84-B51 spec for eMMC card and don't see it
say anywhere that boot0 partition cannot be accessed in HS200 modes.
In practice, I have seen timeouts sometimes when I try to write to the
boot partition in HS200 mode on a dra7xx-evm in U-boot but not
consistently (one would expect if such a thing was forbidden by the spec
then it wouldn't work at all).
Can anyone point to a documentation that says that boot partition cannot
be accessed in HS200 mode? Has anyone else observed failures before this
patch?
I was able to access the boot0 partition in kernel in HS200 mode (log
below). Unless there is code to fallback to a lower speed in kernel also
(which doesn't seem to be the case from a simple searching of the code),
this should prove that boot partitions can be accessed in HS200 speed mode.
Here is the log:
https://pastebin.ubuntu.com/p/W3SB4N3rfn/
Thanks,
Faiz
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
https://lists.denx.de/listinfo/u-boot
^ permalink raw reply [flat|nested] 4+ messages in thread
* [U-Boot] boot partition access at HS200 speed in eMMC
@ 2018-08-02 9:44 ` Faiz Abbas
0 siblings, 0 replies; 4+ messages in thread
From: Faiz Abbas @ 2018-08-02 9:44 UTC (permalink / raw)
To: u-boot
Hi Everyone,
After the following patch from JJ, U-boot shifts to a lower speed mode
from HS200 when accessing a boot partition.
01298da31d mmc: Change mode when switching to a boot partition
I have looked through the JESD84-B51 spec for eMMC card and don't see it
say anywhere that boot0 partition cannot be accessed in HS200 modes.
In practice, I have seen timeouts sometimes when I try to write to the
boot partition in HS200 mode on a dra7xx-evm in U-boot but not
consistently (one would expect if such a thing was forbidden by the spec
then it wouldn't work at all).
Can anyone point to a documentation that says that boot partition cannot
be accessed in HS200 mode? Has anyone else observed failures before this
patch?
I was able to access the boot0 partition in kernel in HS200 mode (log
below). Unless there is code to fallback to a lower speed in kernel also
(which doesn't seem to be the case from a simple searching of the code),
this should prove that boot partitions can be accessed in HS200 speed mode.
Here is the log:
https://pastebin.ubuntu.com/p/W3SB4N3rfn/
Thanks,
Faiz
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: boot partition access at HS200 speed in eMMC
2018-08-02 9:44 ` [U-Boot] " Faiz Abbas
@ 2018-08-06 6:29 ` Faiz Abbas
-1 siblings, 0 replies; 4+ messages in thread
From: Faiz Abbas @ 2018-08-06 6:29 UTC (permalink / raw)
To: U-Boot Mailing List, linux-mmc; +Cc: Ulf Hansson
Hi,
+JJ, Jaehoon Chung
I had CCd them in my original mail but they seem to have been dropped in
the U-boot list.
On Thursday 02 August 2018 03:14 PM, Faiz Abbas wrote:
> Hi Everyone,
>
> After the following patch from JJ, U-boot shifts to a lower speed mode
> from HS200 when accessing a boot partition.
>
> 01298da31d mmc: Change mode when switching to a boot partition
>
> I have looked through the JESD84-B51 spec for eMMC card and don't see it
> say anywhere that boot0 partition cannot be accessed in HS200 modes.
>
> In practice, I have seen timeouts sometimes when I try to write to the
> boot partition in HS200 mode on a dra7xx-evm in U-boot but not
> consistently (one would expect if such a thing was forbidden by the spec
> then it wouldn't work at all).
>
> Can anyone point to a documentation that says that boot partition cannot
> be accessed in HS200 mode? Has anyone else observed failures before this
> patch?
>
> I was able to access the boot0 partition in kernel in HS200 mode (log
> below). Unless there is code to fallback to a lower speed in kernel also
> (which doesn't seem to be the case from a simple searching of the code),
> this should prove that boot partitions can be accessed in HS200 speed mode.
>
> Here is the log:
> https://pastebin.ubuntu.com/p/W3SB4N3rfn/
>
> Thanks,
> Faiz
> _______________________________________________
> U-Boot mailing list
> U-Boot@lists.denx.de
> https://lists.denx.de/listinfo/u-boot
>
_______________________________________________
U-Boot mailing list
U-Boot@lists.denx.de
https://lists.denx.de/listinfo/u-boot
^ permalink raw reply [flat|nested] 4+ messages in thread
* [U-Boot] boot partition access at HS200 speed in eMMC
@ 2018-08-06 6:29 ` Faiz Abbas
0 siblings, 0 replies; 4+ messages in thread
From: Faiz Abbas @ 2018-08-06 6:29 UTC (permalink / raw)
To: u-boot
Hi,
+JJ, Jaehoon Chung
I had CCd them in my original mail but they seem to have been dropped in
the U-boot list.
On Thursday 02 August 2018 03:14 PM, Faiz Abbas wrote:
> Hi Everyone,
>
> After the following patch from JJ, U-boot shifts to a lower speed mode
> from HS200 when accessing a boot partition.
>
> 01298da31d mmc: Change mode when switching to a boot partition
>
> I have looked through the JESD84-B51 spec for eMMC card and don't see it
> say anywhere that boot0 partition cannot be accessed in HS200 modes.
>
> In practice, I have seen timeouts sometimes when I try to write to the
> boot partition in HS200 mode on a dra7xx-evm in U-boot but not
> consistently (one would expect if such a thing was forbidden by the spec
> then it wouldn't work at all).
>
> Can anyone point to a documentation that says that boot partition cannot
> be accessed in HS200 mode? Has anyone else observed failures before this
> patch?
>
> I was able to access the boot0 partition in kernel in HS200 mode (log
> below). Unless there is code to fallback to a lower speed in kernel also
> (which doesn't seem to be the case from a simple searching of the code),
> this should prove that boot partitions can be accessed in HS200 speed mode.
>
> Here is the log:
> https://pastebin.ubuntu.com/p/W3SB4N3rfn/
>
> Thanks,
> Faiz
> _______________________________________________
> U-Boot mailing list
> U-Boot at lists.denx.de
> https://lists.denx.de/listinfo/u-boot
>
^ permalink raw reply [flat|nested] 4+ messages in thread
end of thread, other threads:[~2018-08-06 6:29 UTC | newest]
Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
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2018-08-02 9:44 boot partition access at HS200 speed in eMMC Faiz Abbas
2018-08-02 9:44 ` [U-Boot] " Faiz Abbas
2018-08-06 6:29 ` Faiz Abbas
2018-08-06 6:29 ` [U-Boot] " Faiz Abbas
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