From: jonathanh@nvidia•com (Jon Hunter)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH] ARM64: tegra: Add support for Google Pixel C
Date: Thu, 7 Jan 2016 18:00:56 +0000 [thread overview]
Message-ID: <568EA7D8.1060305@nvidia.com> (raw)
In-Reply-To: <CAL_Jsq++DkgJA--40YBqGZd5BJFkzXfKt_st1kN+ZiVY7yb8OA@mail.gmail.com>
On 07/01/16 17:20, Rob Herring wrote:
> On Thu, Jan 7, 2016 at 10:53 AM, Jon Hunter <jonathanh@nvidia•com> wrote:
>>
>> On 07/01/16 14:11, Arnd Bergmann wrote:
>>> On Thursday 07 January 2016 13:19:44 Jon Hunter wrote:
>
> [...]
>
>> Ok so something like this ...
>>
>> diff --git a/drivers/tty/serial/8250/8250_early.c
>> b/drivers/tty/serial/8250/8250_early.c
>> index af62131af21e..4ce6e2b57534 100644
>> --- a/drivers/tty/serial/8250/8250_early.c
>> +++ b/drivers/tty/serial/8250/8250_early.c
>> @@ -141,7 +141,18 @@ int __init early_serial8250_setup(struct
>> earlycon_device *device,
>> device->con->write = early_serial8250_write;
>> return 0;
>> }
>> +
>> +int __init early_serial8250_mem32_setup(struct earlycon_device *device,
>> + const char *options)
>> +{
>> + device->port.iotype = UPIO_MEM32;
>> + device->port.regshift = 2;
>> +
>> + return early_serial8250_setup(device, options);
>> +}
>> EARLYCON_DECLARE(uart8250, early_serial8250_setup);
>> EARLYCON_DECLARE(uart, early_serial8250_setup);
>> OF_EARLYCON_DECLARE(ns16550, "ns16550", early_serial8250_setup);
>> OF_EARLYCON_DECLARE(ns16550a, "ns16550a", early_serial8250_setup);
>> +OF_EARLYCON_DECLARE(tegra20_uart, "nvidia,tegra20-uart",
>> + early_serial8250_mem32_setup);
>>
>>> Would it be possible to handle the "reg-io-width" parsing in
>>> early_serial8250_setup instead of keying it off the string?
>>
>> Good point. I spent a bit of time looking at this, but I cannot see an
>> easy way to do this unless we check for "reg-io-width" and "reg-shift"
>> in early_init_dt_scan_chosen_serial() and pass to of_setup_earlycon(),
>> however, I am guessing that this would not be ideal as this would happen
>> for non-8250 devices. May be that would be ok, but I am not sure.
>
> There's been one attempt[1] already. It had a few issues easily
> solved, but I haven't seen a follow-up.
Thanks. Adding Paul.
Paul, are you planning a follow-up to your patch? Otherwise, I am happy
to have crack at it. Don't we also need to read the "reg-shift"?
Cheers
Jon
prev parent reply other threads:[~2016-01-07 18:00 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-01-06 9:40 [PATCH] ARM64: tegra: Add support for Google Pixel C Jon Hunter
2016-01-06 9:46 ` Mark Rutland
2016-01-06 12:49 ` Jon Hunter
2016-01-07 13:19 ` Jon Hunter
2016-01-07 14:11 ` Arnd Bergmann
2016-01-07 16:53 ` Jon Hunter
2016-01-07 17:20 ` Rob Herring
2016-01-07 18:00 ` Jon Hunter [this message]
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