From: Graeme Gregory <graeme.gregory@linaro.org>
To: Julien Grall <julien.grall@linaro.org>
Cc: Stefano Stabellini <sstabellini@kernel.org>,
Wei Liu <wei.liu2@citrix.com>,
Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>,
George Dunlap <George.Dunlap@eu.citrix.com>,
Andrew Cooper <andrew.cooper3@citrix.com>,
Ian Jackson <ian.jackson@eu.citrix.com>, Tim Deegan <tim@xen.org>,
Julien Grall <julien.grall@arm.com>,
Jan Beulich <JBeulich@suse.com>,
Bhupinder Thakur <bhupinder.thakur@linaro.org>,
xen-devel@lists.xenproject.org
Subject: Re: [PATCH 3/3 v3] xen: Fix 16550 UART console for HP Moonshot (Aarch64) platform
Date: Mon, 27 Nov 2017 10:37:01 +0000 [thread overview]
Message-ID: <CAGCh1+=q=U665pCNmX2FtyvrMaHtEoVv9sdmsgb5H83iPY0ung@mail.gmail.com> (raw)
In-Reply-To: <2f4ebb63-4295-d249-8966-385c70674d53@linaro.org>
On 27 November 2017 at 10:30, Julien Grall <julien.grall@linaro.org> wrote:
> + Graeme
>
> On 27/11/17 10:06, Jan Beulich wrote:
>>>>>
>>>>> On 24.11.17 at 12:39, <bhupinder.thakur@linaro.org> wrote:
>>>
>>> --- a/xen/drivers/char/ns16550.c
>>> +++ b/xen/drivers/char/ns16550.c
>>> @@ -1571,6 +1571,30 @@ DT_DEVICE_END
>>> #endif /* HAS_DEVICE_TREE */
>>> #if defined(CONFIG_ACPI) && defined(CONFIG_ARM)
>>> +/*
>>> + * APM X-Gene v1 and v2 UART hardware is an 16550 like device but has
>>> its
>>> + * register aligned to 32-bit. In addition, the BIOS also encoded the
>>> + * access width to be 8 bits. This function detects this errata
>>> condition.
>>> + */
>>> +static bool xgene_8250_erratum_present(struct acpi_table_spcr *tb)
>>
>>
>> Is this really to be considered an erratum? From the description it
>> doesn't sound like this couldn't have been a deliberate decision.
>> IOW - does their behavior contradict any spec? (ACPI not providing
>> information in field and access width looks suspicious too - GAS fields
>> exist for both.)
>
>
> I believe the problem here is the firmware table does not describe correctly
> the hardware. I have CCed Graeme which might be able to confirm.
>
Yup, their firmware is wrong, we did tell them many times!
Graeme
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prev parent reply other threads:[~2017-11-27 10:37 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-11-24 11:39 [PATCH 0/3 v3] xen: ACPI/SPCR based initialization of 8250 UART Bhupinder Thakur
2017-11-24 11:39 ` [PATCH 1/3 v3] xen: Refactor 16550 UART code Bhupinder Thakur
2017-11-24 13:37 ` Konrad Rzeszutek Wilk
2017-11-24 16:04 ` Julien Grall
2017-11-24 11:39 ` [PATCH 2/3 v3] xen: Add support for initializing 16550 UART using ACPI Bhupinder Thakur
2017-11-24 13:50 ` Konrad Rzeszutek Wilk
2017-11-24 15:11 ` Andre Przywara
2017-11-24 15:52 ` Julien Grall
2017-11-24 16:05 ` Julien Grall
2017-11-27 10:01 ` Jan Beulich
2017-11-24 11:39 ` [PATCH 3/3 v3] xen: Fix 16550 UART console for HP Moonshot (Aarch64) platform Bhupinder Thakur
2017-11-24 13:51 ` Konrad Rzeszutek Wilk
2017-11-27 10:06 ` Jan Beulich
2017-11-27 10:30 ` Julien Grall
2017-11-27 10:37 ` Graeme Gregory [this message]
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