Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755393Ab1DGH6u (ORCPT ); Thu, 7 Apr 2011 03:58:50 -0400 Received: from eu1sys200aog116.obsmtp.com ([207.126.144.141]:48857 "EHLO eu1sys200aog116.obsmtp.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754085Ab1DGH6t (ORCPT ); Thu, 7 Apr 2011 03:58:49 -0400 Message-ID: <4D9D6807.40800@stericsson.com> Date: Thu, 7 Apr 2011 09:30:15 +0200 From: Mattias Wallin User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.15) Gecko/20101027 Thunderbird/3.0.10 MIME-Version: 1.0 To: Stephen Boyd Cc: Russell King , "linux-kernel@vger.kernel.org" , "linux-arm-msm@vger.kernel.org" , "linux-arm-kernel@lists.infradead.org" , Saravana Kannan , Nicolas Pitre , Andrew Morton , Linus Walleij Subject: Re: [PATCHv5 2/3] ARM: Allow machines to override __delay() References: <1302047800-26720-1-git-send-email-sboyd@codeaurora.org> <1302047800-26720-3-git-send-email-sboyd@codeaurora.org> In-Reply-To: <1302047800-26720-3-git-send-email-sboyd@codeaurora.org> Content-Type: text/plain; charset="ISO-8859-1"; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1224 Lines: 30 On 04/06/2011 01:56 AM, Stephen Boyd wrote: > Some machines want to implement their own __delay() routine based > on fixed rate timers. Expose functionality to set the __delay() > routine at runtime. This should allow two machines with different > __delay() routines to happily co-exist within the same kernel > with minimal overhead. > > Russell expressed concern that using a timer based __delay() > would cause problems when an iomapped device isn't mapped in > prior to a delay call being made (see > http://article.gmane.org/gmane.linux.ports.arm.kernel/78543 for > more info). We can sidestep that issue with this approach since > the __delay() routine_should_ only be pointed to a timer based > delay once the timer has been properly mapped. Up until that > point __delay() and udelay() will use delay_loop() which is > always safe to call. > > This patch is inspired by x86's delay.c > Tested-by: Mattias Wallin Yours, Mattias Wallin -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/