From: sudeep.holla@arm•com (Sudeep Holla)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH 1/2] tty: amba-pl011: fix earlycon register offsets
Date: Tue, 5 Jan 2016 13:45:52 +0000 [thread overview]
Message-ID: <568BC910.5050904@arm.com> (raw)
In-Reply-To: <20160105123018.GU19062@n2100.arm.linux.org.uk>
On 05/01/16 12:30, Russell King - ARM Linux wrote:
> On Tue, Jan 05, 2016 at 12:12:31PM +0000, Sudeep Holla wrote:
>> Hi Russell,
>>
>> On Thu, Dec 24, 2015 at 4:47 PM, Russell King - ARM Linux
>> <linux@arm•linux.org.uk> wrote:
>>> On Thu, Dec 24, 2015 at 09:49:48AM -0600, Timur Tabi wrote:
>>>> The REG_x macros are indices into a table, not register offsets. Since
>>>> earlycon does not have access to the vendor data, we can currently only
>>>> support standard ARM PL011 devices.
>>>>
>>>> Signed-off-by: Timur Tabi <timur@codeaurora•org>
>>>
>>> Please credit me with the change; this was obviously a change I made
>>> when I posted the updated patches, which Greg had failed to take
>>> instead of the original set. Thanks.
>>>
>>
>> I don't see this patch in linux-next. Without this it fails to boot(panics) on
>> ARM64 when earlycon is enabled.
>
[...]
>
> As far as 4.4 goes, I think it's fate was sealed when Greg took the
> wrong set of patches. It's Greg's problem to sort out now.
>
Since it's boot failure, it should be considered as bug fix and merged.
>> Also I think this fix might not be correct
>> for ZTE pl011, though it works for ST and standard PL011.
>
> Yes, earlycon won't work for ZTE PL011. This isn't a big problem at
> the moment, because the patch set doesn't wire up the ZTE PL011 itself.
Yes, I observed that, but still mentioned it just to check if that was
the reason for holding this patch. Thanks for the clarification.
> The reason there is that I'm saying no to using a platform device; I
> really do not like drivers which end up with multiple different probe
> and remove methods. The AMBA PL011 driver is an AMBA primecell driver,
> and it sits on the AMBA primecell bus, not the platform bus.
>
> What I want to see is some way of having the ZTE PL011 appearing on the
> AMBA bus, which means we need to come up with some way to deal with
> primecells which don't have an ID. That is an open issue, as is how
> to deal with earlycon.
>
Understood and thanks for the detailed explanation.
--
Regards,
Sudeep
next prev parent reply other threads:[~2016-01-05 13:45 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-12-24 15:49 [PATCH 1/2] tty: amba-pl011: fix earlycon register offsets Timur Tabi
2015-12-24 15:49 ` [PATCH 2/2] tty: amba-pl011: use iotype instead of access_32b to track 32-bit I/O Timur Tabi
2015-12-24 16:47 ` [PATCH 1/2] tty: amba-pl011: fix earlycon register offsets Russell King - ARM Linux
2016-01-05 12:12 ` Sudeep Holla
2016-01-05 12:30 ` Russell King - ARM Linux
2016-01-05 13:45 ` Sudeep Holla [this message]
2016-01-06 2:43 ` Greg Kroah-Hartman
2016-01-06 10:07 ` Russell King - ARM Linux
2016-01-07 5:17 ` Greg Kroah-Hartman
2016-01-07 18:13 ` Peter Hurley
2015-12-25 1:46 ` Huang Shijie
2015-12-25 1:56 ` Huang Shijie
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