Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161731Ab3DENJJ (ORCPT ); Fri, 5 Apr 2013 09:09:09 -0400 Received: from bear.ext.ti.com ([192.94.94.41]:36115 "EHLO bear.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1161475Ab3DENJH (ORCPT ); Fri, 5 Apr 2013 09:09:07 -0400 Message-ID: <515ECCE1.5070003@ti.com> Date: Fri, 5 Apr 2013 18:38:49 +0530 From: Sourav Poddar User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.9.2.28) Gecko/20120313 Thunderbird/3.1.20 MIME-Version: 1.0 To: Santosh Shilimkar CC: Kevin Hilman , Felipe Balbi , Rajendra nayak , , , , LKML , Subject: Re: [PATCH/Resend 2/2] arm: mach-omap2: prevent UART console idle on suspend while using "no_console_suspend" References: <1363612924-349-1-git-send-email-sourav.poddar@ti.com> <87fvzsilnv.fsf@linaro.org> <5149A221.5@ti.com> <5149A63C.4000102@ti.com> <515AA9CD.5000004@ti.com> <87txnnzesd.fsf@linaro.org> <515E7876.3080407@ti.com> <515E7A13.90303@ti.com> In-Reply-To: <515E7A13.90303@ti.com> 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: 7848 Lines: 199 Hi Santosh, On Friday 05 April 2013 12:45 PM, Santosh Shilimkar wrote: > On Friday 05 April 2013 12:38 PM, Sourav Poddar wrote: >> Hi Kevin, >> On Wednesday 03 April 2013 11:18 PM, Kevin Hilman wrote: >>> Sourav Poddar writes: >>> >>>> Hi Kevin, >>>> On Wednesday 20 March 2013 05:36 PM, Sourav Poddar wrote: >>>>> Realised the list to whom the patch was send got dropped. Ccing >>>>> them all.. >>>>> On Wednesday 20 March 2013 05:18 PM, Sourav Poddar wrote: >>>>>> Hi Kevin, >>>>>> On Tuesday 19 March 2013 12:24 AM, Kevin Hilman wrote: >>>>>>> Sourav Poddar writes: >>>>>>> >>>>>>>> With dt boot, uart wakeup after suspend is non functional on >>>>>>>> omap4/5 while using >>>>>>>> "no_console_suspend" in the bootargs. With "no_console_suspend" >>>>>>>> used, od->flags >>>>>>>> should be ORed with "OMAP_DEVICE_NO_IDLE_ON_SUSPEND", thereby not >>>>>>>> allowing the console >>>>>>>> to idle in the suspend path. For non-dt case, this was taken care >>>>>>>> by platform data. >>>>>>>> >>>>>>>> Tested on omap5430evm, omap4430sdp. >>>>>>>> >>>>>>>> Cc: Santosh Shilimkar >>>>>>>> Cc: Felipe Balbi >>>>>>>> Cc: Rajendra nayak >>>>>>>> Signed-off-by: Sourav Poddar >>>>>>> This patch creates a dependency between omap_device (generic, >>>>>>> device-independent code) and a specific driver (UART.) >>>>>>> >>>>>>> If you need to do something like this that's DT boot specific, then >>>>>>> we probably need some late initcall in serial.c to handle this. >>>>>>> It does >>>>>>> not belong in omap_device. >>>>>>> >>>>>> The following function "omap_device_disable_idle_on_suspend(pdev)" >>>>>> should only >>>>>> be called once the omap device has been build, which in the case of >>>>>> device tree is >>>>>> done in omap_device.c file. Moreover, the above call should be >>>>>> executed conditionally >>>>>> and should depend on the following two parameter. >>>>>> >>>>>> [1] a. Whether "no_console_suspend" is set and >>>>>> b. the device build is a console uart. >>>>>> >>>>>> When I look closely into the serial.c file, I realised that >>>>>> "core_initcall(omap_serial_early_init)" gets called irrespective >>>>>> of dt/non dt boot and will take care of most of the stuff(checking >>>>>> whether >>>>>> "no_console_suspend" is used and which uart is used as a console >>>>>> uart) which the >>>>>> $subject patch is proposing. >>>>>> >>>>>> But the problem is that we need to exchange the parsed information >>>>>> from serial.c to the omap_device file for the condtional execution of >>>>>> "omap_device_disable_idle_on_suspend" >>>>>> >>>>>> In this case, >>>>>> from "serial.c" we need >>>>>> 1. no_console_suspend = true >>>>>> 2. strcpy(console_name, oh_name), where oh_name corresponds to >>>>>> the console uart. >>>>>> >>>>>> then in "omap_device.c" do >>>>>> if (no_console_suspend&& !strcmp(oh->name, console_name)) >>>>>> omap_device_disable_idle_on_suspend(pdev); >>>>>> >>>>>> Please correct if I am understanding it incorrectly. >>>>>> >>>>>> If the above understanding looks good to you, is there a way we can >>>>>> make this >>>>>> exchange of information happen between serial.c and omap_device.c file? >>>> Any input on this? >>>> As I explained earlier, that there is a need to parse information in >>>> serial.c and use that in >>>> omap_device.c only after the device is build. >>> As I explained earlier, any device specific hacks inside omap_device >>> should be a red flag that something has gone wrong. >>> >>> How about fixing the UART driver/core to not runtime suspend if >>> no_console_suspend is given? >>> >>> Then we can get rid of this no_idle_on_suspend hack all together since >>> UART is the only remaining user. >>> >> Yes, that can be done. >> >> I cooked up an experimental patch, based on your above suggestion. The patch is >> inlined along with the mail. I tested the patch and it resolves >> the issue. >> > Would be good to start a new thread. > I will post a new version based on your comments below. >> Depending on whether no_console_suspend is used or not, we can set a variable >> which can be used as a condition in runtime api's in serial driver. >> >> The information whether "no_console_suspend" is used or not is parsed in >> serial.c file, and this need to be communicated to the driver layer. >> > WHY ? > Serial core already knows about 'no_console_suspend' and thats used > to manage console lock. > True. >> In my experimental patch below, I have used an extern variable >> "force_console_suspend_disable". >> >> Do you see a better way of handling this without using extern? >> >> --------- >> From: Sourav Poddar >> Date: Wed, 13 Mar 2013 20:32:36 +0530 >> Subject: [PATCH] arm: mach-omap2: prevent UART console idle on suspend while using "no_console_suspend" >> >> With dt boot, uart wakeup after suspend is non functional while using >> "no_console_suspend" in the bootargs. With "no_console_suspend" used, od->flags >> should be ORed with "OMAP_DEVICE_NO_IDLE_ON_SUSPEND", thereby not allowing the console >> to idle in the suspend path. >> >> Tested on omap5430evm, omap4430sdp. >> >> Signed-off-by: Sourav Poddar >> --- >> arch/arm/mach-omap2/serial.c | 6 ++++-- >> drivers/tty/serial/omap-serial.c | 6 +++++- >> 2 files changed, 9 insertions(+), 3 deletions(-) >> >> diff --git a/arch/arm/mach-omap2/serial.c b/arch/arm/mach-omap2/serial.c >> index f660156..427c407 100644 >> --- a/arch/arm/mach-omap2/serial.c >> +++ b/arch/arm/mach-omap2/serial.c >> @@ -51,7 +51,7 @@ >> #define DEFAULT_AUTOSUSPEND_DELAY -1 >> >> #define MAX_UART_HWMOD_NAME_LEN 16 >> - >> +int force_console_suspend_disable; >> struct omap_uart_state { >> int num; >> >> @@ -207,8 +207,10 @@ static int __init omap_serial_early_init(void) >> uart_name, uart->num); >> } >> >> - if (cmdline_find_option("no_console_suspend")) >> + if (cmdline_find_option("no_console_suspend")) { >> + force_console_suspend_disable = 1; >> no_console_suspend = true; >> + } >> >> /* >> * omap-uart can be used for earlyprintk logs >> diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c >> index 08332f3..395ade8 100644 >> --- a/drivers/tty/serial/omap-serial.c >> +++ b/drivers/tty/serial/omap-serial.c >> @@ -43,6 +43,7 @@ >> #include >> #include >> >> +extern int force_console_suspend_disable; > This is no good. You need to use the information from > core serial layer > Ok. Will change. >> #define OMAP_MAX_HSUART_PORTS 6 >> >> #define UART_BUILD_REVISION(x, y) (((x)<< 8) | (y)) >> @@ -1582,7 +1583,7 @@ static int serial_omap_runtime_suspend(struct device *dev) >> struct uart_omap_port *up = dev_get_drvdata(dev); >> struct omap_uart_port_info *pdata = dev->platform_data; >> >> - if (!up) >> + if (!up || force_console_suspend_disable) >> return -EINVAL; >> >> if (!pdata) >> @@ -1614,6 +1615,9 @@ static int serial_omap_runtime_resume(struct device *dev) >> >> int loss_cnt = serial_omap_get_context_loss_count(up); >> >> + if (force_console_suspend_disable) >> + return -EINVAL; >> + >> if (loss_cnt< 0) { >> dev_err(dev, "serial_omap_get_context_loss_count failed : %d\n", >> loss_cnt); -- 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/