From mboxrd@z Thu Jan 1 00:00:00 1970 From: Julien Grall Subject: Re: [PATCH 3/4] xen: set the right flags when enabling interrupts for 8250 Date: Fri, 26 Jul 2013 11:42:46 +0100 Message-ID: <51F252A6.1060602@linaro.org> References: <1374238666-5870-1-git-send-email-baozich@gmail.com> <1374238666-5870-4-git-send-email-baozich@gmail.com> <1374243315.13645.85.camel@kazak.uk.xensource.com> <95E1BD1E-4580-48B9-A86B-906B0D32E4A4@gmail.com> <3AA43164-D350-4E67-AAD2-0A07B19BE695@gmail.com> <51F10950.8010803@linaro.org> <89ED3C27-8D2C-4E2E-86F8-83255D3B618F@gmail.com> <51F11B18.80407@linaro.org> <69476C12-4163-4AB8-A927-9BB8F8F3E8C7@gmail.com> <00ED6B47-36B1-4C4F-B5E3-249575BD57AF@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <00ED6B47-36B1-4C4F-B5E3-249575BD57AF@gmail.com> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: Chen Baozi Cc: Keir Fraser , Ian Campbell , xen-devel@lists.xen.org List-Id: xen-devel@lists.xenproject.org On 07/26/2013 04:31 AM, Chen Baozi wrote: > > On Jul 26, 2013, at 9:14 AM, Chen Baozi wrote: > >> >> On Jul 25, 2013, at 8:33 PM, Julien Grall wrote: >> >>> On 07/25/2013 12:31 PM, Chen Baozi wrote: >>>> >>>> On Jul 25, 2013, at 7:17 PM, Julien Grall wrote: >>>> >>>>> On 07/25/2013 10:14 AM, Chen Baozi wrote: >>>>> >>>>>> Besides this test, I noticed that we set a timer to poll UART after enabling >>>>>> the interrupt. And the timer initialization codes are platform specific, which >>>>>> should be implemented in xen/arch/arm/platforms/omap5.c for example. However, >>>>>> I haven't done this yet. (I used to plan to turn to this work after UART porting >>>>>> has been done.) Is it a possible factor that may cause my issues? >>>>> >>>>> Xen uses the arch timers to handle the time. On some platform (for >>>>> instance the Arndale), it's not enabled by default. >>>>> >>>>> If the omap5 boot with the arch timers enabled, you don't need to >>>>> implement the init_time callback. >>>>> >>>>> Do you know if Xen receives timer interrupts? >>>> >>>> Any way that I could confirm this? >>>> >>>> There is a line of boot message: >>>> >>>> "Using generic timer at 0 KHz." >>>> >>> >>> It seems the arch timer is not configured/enabled. Do you know if U-boot >>> enables it? >> >> I could see clocks.c/clocks.o in its u-boot sources, but I don't think U-boot has already enabled it, for I could read such lines from Linux kernel boot messages: Are you trying to boot Linux on bare metal or as dom0? >> """ >> OMAP clockevent source: GPTIMER1 at 32768 Hz >> sched_clock: 32 bits at 32kHz, resolution 30517ns, wraps every 131071999s >> OMAP clocksource: 32k_counter at 32768 Hz >> arch_timer: No interrupt available, giving up Do you have a "arm,armv7-timer" compatible node in your DTS with interrupts? Here Linux can't find an appropriate interrupt. >> omap5_realtime_timer_init: arch_timer_register failed -22 >> >>> >>> It's not clear to me, how you need to implement init_time. Do you have a >>> datasheet with the board? If yes, is there a section for the section timer? >> >> Yes, TI has published an 49.6MB Technical Reference Manual online with 88 pages section about timer. > > Wait. I think I might make a mistake. The "arch timer" is different from "timer" as devices, right? The timer section in Technical Reference Manual seems to be the latter one, for it is connect to the Level-4 interconnect of OMAP5432 and described as "ti,omap5430-timer" in DTS. I think the "arch timer" you mentioned should refer to "arm,armv7-timer", right? By "arch timer" I mean "arm,armv7-timer". -- Julien