From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751992AbdHAJa3 (ORCPT ); Tue, 1 Aug 2017 05:30:29 -0400 Received: from mail-pf0-f172.google.com ([209.85.192.172]:33550 "EHLO mail-pf0-f172.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751680AbdHAJ2y (ORCPT ); Tue, 1 Aug 2017 05:28:54 -0400 From: Viresh Kumar To: Greg Kroah-Hartman , Jonathan Corbet Cc: Viresh Kumar , Vincent Guittot , Mark Brown , Stephen Boyd , Rajendra Nayak , Shiraz Hashim , linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org, robdclark@gmail.com, linux-doc@vger.kernel.org Subject: [PATCH V3 2/8] drivers: boot_constraint: Add boot_constraints_disable kernel parameter Date: Tue, 1 Aug 2017 14:53:43 +0530 Message-Id: <4bec0c3e58f76e06e5305c5ddbab859e2a87935e.1501578037.git.viresh.kumar@linaro.org> X-Mailer: git-send-email 2.13.0.71.gd7076ec9c9cb In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Users must be given an option to discard any constraints set by bootloaders. For example, consider that a constraint is set for the LCD controller's supply and the LCD driver isn't loaded by the kernel. If the user doesn't need to use the LCD device, then he shouldn't be forced to honour the constraint. We can also think about finer control of such constraints with help of some sysfs files, but a kernel parameter is fine to begin with. Tested-by: Rajendra Nayak Signed-off-by: Viresh Kumar --- Documentation/admin-guide/kernel-parameters.txt | 3 +++ drivers/base/boot_constraints/core.c | 17 +++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index d9c171ce4190..0706d1b6004d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -426,6 +426,9 @@ embedded devices based on command line input. See Documentation/block/cmdline-partition.txt + boot_constraints_disable + Do not set any boot constraints for devices. + boot_delay= Milliseconds to delay each printk during boot. Values larger than 10 seconds (10000) are changed to no delay (0). diff --git a/drivers/base/boot_constraints/core.c b/drivers/base/boot_constraints/core.c index 366a05d6d9ba..e0c33b2b216f 100644 --- a/drivers/base/boot_constraints/core.c +++ b/drivers/base/boot_constraints/core.c @@ -24,6 +24,17 @@ static LIST_HEAD(constraint_devices); static DEFINE_MUTEX(constraint_devices_mutex); +static bool boot_constraints_disabled; + +static int __init constraints_disable(char *str) +{ + boot_constraints_disabled = true; + pr_debug("disabled\n"); + + return 0; +} +early_param("boot_constraints_disable", constraints_disable); + /* Boot constraints core */ static struct constraint_dev *constraint_device_find(struct device *dev) @@ -126,6 +137,9 @@ int dev_boot_constraint_add(struct device *dev, struct constraint *constraint; int ret; + if (boot_constraints_disabled) + return -ENODEV; + mutex_lock(&constraint_devices_mutex); /* Find or add the cdev type first */ @@ -184,6 +198,9 @@ void dev_boot_constraints_remove(struct device *dev) struct constraint_dev *cdev; struct constraint *constraint, *temp; + if (boot_constraints_disabled) + return; + mutex_lock(&constraint_devices_mutex); cdev = constraint_device_find(dev); -- 2.13.0.71.gd7076ec9c9cb From mboxrd@z Thu Jan 1 00:00:00 1970 From: viresh.kumar@linaro.org (Viresh Kumar) Date: Tue, 1 Aug 2017 14:53:43 +0530 Subject: [PATCH V3 2/8] drivers: boot_constraint: Add boot_constraints_disable kernel parameter In-Reply-To: References: Message-ID: <4bec0c3e58f76e06e5305c5ddbab859e2a87935e.1501578037.git.viresh.kumar@linaro.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org Users must be given an option to discard any constraints set by bootloaders. For example, consider that a constraint is set for the LCD controller's supply and the LCD driver isn't loaded by the kernel. If the user doesn't need to use the LCD device, then he shouldn't be forced to honour the constraint. We can also think about finer control of such constraints with help of some sysfs files, but a kernel parameter is fine to begin with. Tested-by: Rajendra Nayak Signed-off-by: Viresh Kumar --- Documentation/admin-guide/kernel-parameters.txt | 3 +++ drivers/base/boot_constraints/core.c | 17 +++++++++++++++++ 2 files changed, 20 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index d9c171ce4190..0706d1b6004d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -426,6 +426,9 @@ embedded devices based on command line input. See Documentation/block/cmdline-partition.txt + boot_constraints_disable + Do not set any boot constraints for devices. + boot_delay= Milliseconds to delay each printk during boot. Values larger than 10 seconds (10000) are changed to no delay (0). diff --git a/drivers/base/boot_constraints/core.c b/drivers/base/boot_constraints/core.c index 366a05d6d9ba..e0c33b2b216f 100644 --- a/drivers/base/boot_constraints/core.c +++ b/drivers/base/boot_constraints/core.c @@ -24,6 +24,17 @@ static LIST_HEAD(constraint_devices); static DEFINE_MUTEX(constraint_devices_mutex); +static bool boot_constraints_disabled; + +static int __init constraints_disable(char *str) +{ + boot_constraints_disabled = true; + pr_debug("disabled\n"); + + return 0; +} +early_param("boot_constraints_disable", constraints_disable); + /* Boot constraints core */ static struct constraint_dev *constraint_device_find(struct device *dev) @@ -126,6 +137,9 @@ int dev_boot_constraint_add(struct device *dev, struct constraint *constraint; int ret; + if (boot_constraints_disabled) + return -ENODEV; + mutex_lock(&constraint_devices_mutex); /* Find or add the cdev type first */ @@ -184,6 +198,9 @@ void dev_boot_constraints_remove(struct device *dev) struct constraint_dev *cdev; struct constraint *constraint, *temp; + if (boot_constraints_disabled) + return; + mutex_lock(&constraint_devices_mutex); cdev = constraint_device_find(dev); -- 2.13.0.71.gd7076ec9c9cb