Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757871AbcCaSYE (ORCPT ); Thu, 31 Mar 2016 14:24:04 -0400 Received: from mail-lf0-f54.google.com ([209.85.215.54]:35935 "EHLO mail-lf0-f54.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757525AbcCaSX5 (ORCPT ); Thu, 31 Mar 2016 14:23:57 -0400 Subject: Re: [PATCH v7 1/5] of/serial: move earlycon early_param handling to serial To: Greg Kroah-Hartman References: <1459431629-27934-1-git-send-email-aleksey.makarov@linaro.org> <1459431629-27934-2-git-send-email-aleksey.makarov@linaro.org> <20160331163203.GC10256@kroah.com> <56FD5894.3060105@linaro.org> <20160331173732.GA10567@kroah.com> Cc: Russell King , linux-serial@vger.kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, "Rafael J . Wysocki" , Len Brown , Leif Lindholm , Graeme Gregory , Al Stone , Christopher Covington , Yury Norov , Peter Hurley , Andy Shevchenko , "Zheng, Lv" , Rob Herring , Frank Rowand , Grant Likely , Jiri Slaby , devicetree@vger.kernel.org From: Aleksey Makarov Message-ID: <56FD6AAE.3090001@linaro.org> Date: Thu, 31 Mar 2016 21:21:34 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:38.0) Gecko/20100101 Thunderbird/38.7.0 MIME-Version: 1.0 In-Reply-To: <20160331173732.GA10567@kroah.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5227 Lines: 142 On 03/31/2016 08:37 PM, Greg Kroah-Hartman wrote: > On Thu, Mar 31, 2016 at 08:04:20PM +0300, Aleksey Makarov wrote: >> >> >> On 03/31/2016 07:32 PM, Greg Kroah-Hartman wrote: >>> On Thu, Mar 31, 2016 at 04:40:23PM +0300, Aleksey Makarov wrote: >>>> From: Leif Lindholm >>>> >>>> We have multiple "earlycon" early_param handlers - merge the DT one into >>>> the main earlycon one. It's a cleanup that also will be useful >>>> to defer setting up DT console until ACPI/DT decision is made. >>>> >>>> Rename the exported function to avoid clashing with the function from >>>> arch/microblaze/kernel/prom.c >>>> >>>> Signed-off-by: Leif Lindholm >>>> Signed-off-by: Aleksey Makarov >>>> Acked-by: Rob Herring >>>> --- >>>> drivers/of/fdt.c | 11 +---------- >>>> drivers/tty/serial/earlycon.c | 2 +- >>>> include/linux/of_fdt.h | 2 ++ >>>> 3 files changed, 4 insertions(+), 11 deletions(-) >>>> >>>> diff --git a/drivers/of/fdt.c b/drivers/of/fdt.c >>>> index 3349d2a..b50f775 100644 >>>> --- a/drivers/of/fdt.c >>>> +++ b/drivers/of/fdt.c >>>> @@ -805,7 +805,7 @@ static inline void early_init_dt_check_for_initrd(unsigned long node) >>>> >>>> #ifdef CONFIG_SERIAL_EARLYCON >>>> >>>> -static int __init early_init_dt_scan_chosen_serial(void) >>>> +int __init early_init_dt_scan_chosen_stdout(void) >>>> { >>>> int offset; >>>> const char *p, *q, *options = NULL; >>>> @@ -849,15 +849,6 @@ static int __init early_init_dt_scan_chosen_serial(void) >>>> } >>>> return -ENODEV; >>>> } >>>> - >>>> -static int __init setup_of_earlycon(char *buf) >>>> -{ >>>> - if (buf) >>>> - return 0; >>>> - >>>> - return early_init_dt_scan_chosen_serial(); >>>> -} >>>> -early_param("earlycon", setup_of_earlycon); >>>> #endif >>>> >>>> /** >>>> diff --git a/drivers/tty/serial/earlycon.c b/drivers/tty/serial/earlycon.c >>>> index 067783f..7aae655 100644 >>>> --- a/drivers/tty/serial/earlycon.c >>>> +++ b/drivers/tty/serial/earlycon.c >>>> @@ -209,7 +209,7 @@ static int __init param_setup_earlycon(char *buf) >>>> * don't generate a warning from parse_early_params() in that case >>>> */ >>>> if (!buf || !buf[0]) >>>> - return 0; >>>> + return early_init_dt_scan_chosen_stdout(); >>>> >>>> err = setup_earlycon(buf); >>>> if (err == -ENOENT || err == -EALREADY) >>>> diff --git a/include/linux/of_fdt.h b/include/linux/of_fdt.h >>>> index 2fbe868..5cfe322 100644 >>>> --- a/include/linux/of_fdt.h >>>> +++ b/include/linux/of_fdt.h >>>> @@ -63,6 +63,7 @@ extern int early_init_dt_scan_chosen(unsigned long node, const char *uname, >>>> int depth, void *data); >>>> extern int early_init_dt_scan_memory(unsigned long node, const char *uname, >>>> int depth, void *data); >>>> +extern int early_init_dt_scan_chosen_stdout(void); >>>> extern void early_init_fdt_scan_reserved_mem(void); >>>> extern void early_init_fdt_reserve_self(void); >>>> extern void early_init_dt_add_memory_arch(u64 base, u64 size); >>>> @@ -91,6 +92,7 @@ extern void early_get_first_memblock_info(void *, phys_addr_t *); >>>> extern u64 of_flat_dt_translate_address(unsigned long node); >>>> extern void of_fdt_limit_memory(int limit); >>>> #else /* CONFIG_OF_FLATTREE */ >>>> +static inline int early_init_dt_scan_chosen_stdout(void) { return -ENODEV; } >>> >>> Doesn't this change the default logic? Today you are returning 0 if you >>> don't have this config option set, >> >> I am not sure I understand this. Which return value do you mean? >> >> 1. early_init_dt_scan_chosen_stdout() >> >> Today if CONFIG_OF_FLATTREE is not set then early_init_dt_scan_chosen_stdout() does not exist. > > It "exists" in that you return -ENODEV, right? Look at the place where > you called this function, It's param_setup_earlycon() so see below for explanations. > previously you returned 0, now you return this > function call's return value. > >> 2. param_setup_earlycon() >> >> Today we have 2 handlers for "earlycon" option. One (in fdt.c) is for the option without args, >> and another (earlycon.c) always expects agrs. But both return 0 for the opposite cases becasue they >> can not check what another hander returns. >> >> Now we have just one handler and it can return correct value. > > I don't understand. This patch deletes early_param("earlycon", setup_of_earlycon) from fdt.c and keeps early_param("earlycon", param_setup_earlycon) in earlycon.c. Assume "earlycon" kernel command line parameter was passed without arguments. Before this patch: early_init_dt_scan_chosen_stdout() is called from setup_of_earlycon() where its return value is returned to parse_early_param() After this patch: early_init_dt_scan_chosen_stdout() is called from param_setup_earlycon() so we should return its return value from param_setup_earlycon() if we want to pass it to parse_early_param(). >>> and now you return -ENODEV, did you >>> test this out? >> >> Yes, I tested it. > > On what platforms? With what configurations? platform: QEMU configuration options: with/without acpi, dt command line options: with/without "earlycon", "earlycon=..." Thank you Aleksey Makarov