On Fri, Sep 20, 2019 at 05:39:06PM +0200, Alexandre Belloni wrote: > It is not allowed to sleep to early in the boot process and this may lead > to kernel issues if the bootloader didn't prepare the slow clock and main > clock. > > This results in the following error and dump stack on the AriettaG25: > bad: scheduling from the idle thread! > > Ensure it is possible to sleep, else simply have a delay. > > Reported-by: Uwe Kleine-König <u.kleine-koe...@pengutronix.de> > Signed-off-by: Alexandre Belloni <alexandre.bell...@bootlin.com>
Tested-by: Uwe Kleine-König <u.kleine-koe...@pengutronix.de> See below for a comment. > Note that this was already discussed a while ago and Arnd said this approach > was > reasonable: > https://lore.kernel.org/lkml/6120818.MyeJZ74hYa@wuerfel/ > > drivers/clk/at91/clk-main.c | 5 ++++- > drivers/clk/at91/sckc.c | 20 ++++++++++++++++---- > 2 files changed, 20 insertions(+), 5 deletions(-) > > diff --git a/drivers/clk/at91/clk-main.c b/drivers/clk/at91/clk-main.c > index f607ee702c83..ccd48e7a3d74 100644 > --- a/drivers/clk/at91/clk-main.c > +++ b/drivers/clk/at91/clk-main.c > @@ -293,7 +293,10 @@ static int clk_main_probe_frequency(struct regmap > *regmap) > regmap_read(regmap, AT91_CKGR_MCFR, &mcfr); > if (mcfr & AT91_PMC_MAINRDY) > return 0; > - usleep_range(MAINF_LOOP_MIN_WAIT, MAINF_LOOP_MAX_WAIT); > + if (system_state < SYSTEM_RUNNING) > + udelay(MAINF_LOOP_MIN_WAIT); > + else > + usleep_range(MAINF_LOOP_MIN_WAIT, MAINF_LOOP_MAX_WAIT); Given that this construct is introduced several times, I wonder if we want something like: static inline void early_usleep_range(unsigned long min, unsigned long max) { if (system_state < SYSTEM_RUNNING) udelay(min); else usleep_range(min, max); } Best regards Uwe -- Pengutronix e.K. | Uwe Kleine-König | Industrial Linux Solutions | http://www.pengutronix.de/ |
