Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161768Ab3DEHNg (ORCPT ); Fri, 5 Apr 2013 03:13:36 -0400 Received: from arroyo.ext.ti.com ([192.94.94.40]:55582 "EHLO arroyo.ext.ti.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751204Ab3DEHNe (ORCPT ); Fri, 5 Apr 2013 03:13:34 -0400 Message-ID: <515E7A13.90303@ti.com> Date: Fri, 5 Apr 2013 12:45:31 +0530 From: Santosh Shilimkar User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Sourav Poddar 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> In-Reply-To: <515E7876.3080407@ti.com> Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7498 Lines: 195 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. > 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. > 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 > #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/