From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jon Hunter Subject: Re: [PATCH] ARM64: tegra: Add support for Google Pixel C Date: Thu, 7 Jan 2016 18:00:56 +0000 Message-ID: <568EA7D8.1060305@nvidia.com> References: <1452073222-2956-1-git-send-email-jonathanh@nvidia.com> <568D0D70.4020309@nvidia.com> <568E65F0.2070201@nvidia.com> <4442990.rM1mk43t6M@wuerfel> <568E9804.5020503@nvidia.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: Sender: linux-tegra-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Rob Herring , paul.burton-1AXoQHu6uovQT0dZR+AlfA@public.gmane.org Cc: Arnd Bergmann , Mark Rutland , Pawel Moll , Ian Campbell , Kumar Gala , Stephen Warren , Thierry Reding , Alexandre Courbot , Olof Johansson , "linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org" , "devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , "linux-tegra-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" List-Id: linux-tegra@vger.kernel.org On 07/01/16 17:20, Rob Herring wrote: > On Thu, Jan 7, 2016 at 10:53 AM, Jon Hunter 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