From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tom Rini Date: Fri, 14 Oct 2016 21:45:08 -0400 Subject: [U-Boot] [PATCH v2] watchdog: Fix Watchdog Reset while in U-Boot Prompt In-Reply-To: <20160919115944.GA20369@tng> References: <20160801133918.DA1251E4323@proxy.tng.vnc.biz> <20160919115944.GA20369@tng> Message-ID: <20161015014508.GE18591@bill-the-cat> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Mon, Sep 19, 2016 at 01:59:44PM +0200, Andreas Reichel wrote: > Hi Tom, > > is my patch going to be applied or is the problem resolved > otherwhise? Sorry, lost in my patchwork queue. I'll pick this up soon now. > > Kind regards > Andreas > > On Mo, Sep 05, 2016 at 07:04:53 -0600, Simon Glass wrote: > > +Tom, in case this should go into the release. > > > > On 1 August 2016 at 05:49, Andreas J. Reichel > > wrote: > > > This patch fixes unwanted watchdog resets while the user enters > > > a command at the U-Boot prompt. > > > > > > As found on the CM-FX6 board from Compulab, when having enabled the > > > watchdog, a missing WATCHDOG_RESET call in _serial_tstc() in > > > (/drivers/serial/serial-uclass.c) causes this and alike boards to > > > reset when the watchdog's timeout has elapsed while waiting at the > > > U-Boot prompt. > > > > > > Despite the user could press several keys within the watchdog > > > timeout limit, the while loop in cli_readline.c, line 261, does only > > > call WATCHDOG_RESET if first == 1, which gets set to 0 in the 1st > > > loop iteration. This leads to a watchdog timeout no matter if the > > > user presses keys or not. > > > > > > The problem is solved with a call to WATCHDOG_RESET in _serial_tstc, > > > defined in drivers/serial/serial-uclass.c. > > > > > > Since the macro WATCHDOG_RESET expands to {} if watchdog support > > > isn't configured, there's no need to surround it by #ifdef in this > > > case. > > > > > > * Symptom: > > > U-Boot resets after watchdog times out when in commandline prompt > > > and watchdog is enabled. > > > > > > * Reasoning: > > > When U-Boot shows the commandline prompt, the following function > > > call stack is executed while waiting for a keypress: > > > > > > common/main.c: > > > main_loop => common/cli.c: cli_loop() => > > > common/cli_hush.c: > > > parse_file_outer => parse_stream_outer => > > > parse_stream => b_getch(i) => > > > i->get(i) => file_get => > > > get_user_input => cmdedit_read_input => > > > uboot_cli_readline => > > > common/cli_readline.c: > > > cli_readline => cli_readline_into_buffer => > > > cread_line => getcmd_getch (== getc) => > > > commonn/console.c: > > > fgetc => console_tstc > > > > > > - in console_tstc line 181: > > > If dev->tstc(dev) returns 0, the global tstcdev variable doesn't > > > get set. This is the case if no character is in the serial buffer. > > > > > > - in fgetc(int file), line 297: > > > Program flow keeps looping because tstcdev does not get set. > > > Therefore WATCHDOG_RESET is not called, as mx_serial_tstc from > > > drivers/serial/serial_mxc.c does not call it. > > > > > > - Initialization calls drv_system_init in stdio.c, which sets > > > dev.tstc = stdio_serial_tstc. Thus, dev->tstc(dev) calls serial_tstc() > > > which in turn calls _serial_tstc(). > > > > > > Hence, _serial_tstc() needs to call WATCHDOG_RESET() to periodically > > > reset the watchdog while cli_readline waits for user input. > > > > > > Signed-off-by: Christian Storm > > > Signed-off-by: Jan Kiszka > > > Signed-off-by: Andreas J. Reichel > > > --- > > > > > > Changes in v2: > > > - Move WATCHDOG_RESET() call from common/console.c to > > > drivers/serial/serial-uclass.c. > > > > > > drivers/serial/serial-uclass.c | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/drivers/serial/serial-uclass.c b/drivers/serial/serial-uclass.c > > > index 0ce5c44..72cf808 100644 > > > --- a/drivers/serial/serial-uclass.c > > > +++ b/drivers/serial/serial-uclass.c > > > @@ -155,6 +155,7 @@ static int _serial_tstc(struct udevice *dev) > > > { > > > struct dm_serial_ops *ops = serial_get_ops(dev); > > > > > > + WATCHDOG_RESET(); > > > if (ops->pending) > > > return ops->pending(dev, true); > > > > Great explanation, thank you. > > > > Acked-by: Simon Glass > > > > > > > > -- > > > 2.8.2 > > > > > -- > Andreas Reichel > Dipl.-Phys. (Univ.) > Software Consultant > > Andreas.Reichel at tngtech.com > +49-174-3180074 > > TNG Technology Consulting GmbH, Betastr. 13a, 85774 Unterf?hring > Gesch?ftsf?hrer: Henrik Klagges, Christoph Stock, Dr. Robert Dahlke > Sitz: Unterf?hring * Amtsgericht M?nchen * HRB 135082 -- Tom -------------- next part -------------- A non-text attachment was scrubbed... Name: signature.asc Type: application/pgp-signature Size: 819 bytes Desc: Digital signature URL: