From: Duc Dang <dhdang@apm.com>
To: Jon Masters <jcm@redhat.com>, Mark Salter <msalter@redhat.com>
Cc: Rafael Wysocki <rafael@kernel.org>, Arnd Bergmann <arnd@arndb.de>,
linux-arm <linux-arm-kernel@lists.infradead.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
patches <patches@apm.com>,
Aleksey Makarov <aleksey.makarov@linaro.org>,
"linux-acpi@vger.kernel.org" <linux-acpi@vger.kernel.org>,
Grant Likely <grant.likely@hpe.com>
Subject: Re: [SPCR] mmio32 iotype access requirements for X-Gene 8250(_dw) UART
Date: Sun, 4 Dec 2016 02:35:28 -0800 [thread overview]
Message-ID: <CADaLNDnTFYhJK76DhRNvxb5eAEQGtaJtag1CoyLb73iweUkMGw@mail.gmail.com> (raw)
In-Reply-To: <c6a0c134-2fde-21c2-03fb-6e1961161a26@redhat.com>
On Sat, Dec 3, 2016 at 12:33 PM, Jon Masters <jcm@redhat.com> wrote:
> Hi Mark,
>
> On 12/03/2016 12:15 PM, Mark Salter wrote:
>> On Sat, 2016-12-03 at 05:06 -0500, Jon Masters wrote:
>
>>> There is a broader problem with X-Gene SPCR support. The problem is
>>> that the 16550 UART in X-Gene requires the 32-bit access quirk (the
>>> iotype is set to UPIO_MEM32 for the APMC0D08 device). This means
>>> that when univ8250_console_match runs later, it will compare the
>>> iotype (MEM32) with the type previously registered with the
>>> kernel when the earlycon setup the preferred console.
>>
>> Linaro has a kernel patch which looks at the bit_width field of the
>> port address:
>>
>> Author: Aleksey Makarov <aleksey.makarov@linaro.org>
>> Date: Thu Apr 28 19:52:38 2016 +0300
>>
>> serial: SPCR: check bit width for the 16550 UART
>>
>> The SPCR in 3.06.25 firmware has a bit_width field set to 32 and with the
>> above patch, I don't need to use console=. But HP firmware on m400 sets
>> bit width to 8 so that needs a firmware fix to work with above.
Will this patch be posted for upstream?
>
> Indeed, thanks. Graeme also mentioned that last night. I think this
> a good solution for the moment, but still that it makes sense to
> have a new 16650 UART type defined in the DBG2 spec for those
> requiring 32-bit access (to mirror the type D for pl011). I
> heard back from Microsoft this morning that they're looking.
Yes, thanks, Jon. It will be nice to have a new 16550 UART type for
those requiring 32-bit access.
>
> Jon.
>
> --
> Computer Architect | Sent from my Fedora powered laptop
>
Regards,
Duc Dang.
next prev parent reply other threads:[~2016-12-04 10:42 UTC|newest]
Thread overview: 42+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-30 23:42 [PATCH v3] PCI/ACPI: xgene: Add ECAM quirk for X-Gene PCIe controller Duc Dang
2016-12-01 15:08 ` Mark Salter
2016-12-01 19:17 ` Jon Masters
2016-12-01 19:58 ` Duc Dang
2016-12-01 18:33 ` Bjorn Helgaas
2016-12-01 19:20 ` Mark Salter
2016-12-01 19:26 ` Jon Masters
2016-12-01 19:41 ` Bjorn Helgaas
2016-12-01 22:10 ` Duc Dang
2016-12-01 22:31 ` Jon Masters
2016-12-01 23:07 ` Bjorn Helgaas
2016-12-01 23:22 ` Duc Dang
2016-12-02 4:08 ` Jon Masters
2016-12-02 6:31 ` Jon Masters
2016-12-02 7:34 ` Duc Dang
2016-12-02 8:08 ` Jon Masters
2016-12-02 23:39 ` Bjorn Helgaas
2016-12-03 0:33 ` Jon Masters
2016-12-05 21:21 ` Bjorn Helgaas
2016-12-06 19:46 ` Jon Masters
2016-12-06 20:18 ` Bjorn Helgaas
2016-12-06 20:23 ` Jon Masters
2016-12-13 21:35 ` Jon Masters
2016-12-03 7:06 ` Duc Dang
2016-12-05 21:20 ` Bjorn Helgaas
2016-12-05 21:40 ` Duc Dang
2016-12-05 23:31 ` Jon Masters
2016-12-02 2:27 ` [PATCH v4 1/1] " Duc Dang
2016-12-02 7:12 ` Jon Masters
2016-12-02 7:36 ` Duc Dang
2016-12-02 8:11 ` Jon Masters
2016-12-02 19:39 ` Duc Dang
2016-12-02 19:59 ` Jon Masters
2016-12-03 10:06 ` [SPCR] mmio32 iotype access requirements for X-Gene 8250(_dw) UART Jon Masters
2016-12-03 17:11 ` Graeme Gregory
2016-12-03 17:15 ` Mark Salter
2016-12-03 20:33 ` Jon Masters
2016-12-04 10:35 ` Duc Dang [this message]
2016-12-02 11:36 ` [PATCH v4 1/1] PCI/ACPI: xgene: Add ECAM quirk for X-Gene PCIe controller Graeme Gregory
2016-12-02 2:52 ` [PATCH v3] " Duc Dang
2016-12-05 21:53 ` Bjorn Helgaas
2016-12-05 22:09 ` Duc Dang
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