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clk: at91: avoid sleeping early 

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-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lkml.kernel.org/r/20190920153906.20887-1-alexandre.belloni@bootlin.com
Fixes: 80eded6ce8 ("clk: at91: add slow clks driver")
Tested-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
This commit is contained in:
Alexandre Belloni 2019-09-20 17:39:06 +02:00 committed by Stephen Boyd
parent b234fe9558
commit 658fd65cf0
2 changed files with 20 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
drivers/clk/at91/clk-main.c
View File

@ -297,7 +297,10 @@ 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);
} while (time_before(prep_time, timeout));
return -ETIMEDOUT;

20
drivers/clk/at91/sckc.c
View File

@ -76,7 +76,10 @@ static int clk_slow_osc_prepare(struct clk_hw *hw)
writel(tmp | osc->bits->cr_osc32en, sckcr);
usleep_range(osc->startup_usec, osc->startup_usec + 1);
if (system_state < SYSTEM_RUNNING)
udelay(osc->startup_usec);
else
usleep_range(osc->startup_usec, osc->startup_usec + 1);
return 0;
}
@ -187,7 +190,10 @@ static int clk_slow_rc_osc_prepare(struct clk_hw *hw)
writel(readl(sckcr) | osc->bits->cr_rcen, sckcr);
usleep_range(osc->startup_usec, osc->startup_usec + 1);
if (system_state < SYSTEM_RUNNING)
udelay(osc->startup_usec);
else
usleep_range(osc->startup_usec, osc->startup_usec + 1);
return 0;
}
@ -288,7 +294,10 @@ static int clk_sam9x5_slow_set_parent(struct clk_hw *hw, u8 index)
writel(tmp, sckcr);
usleep_range(SLOWCK_SW_TIME_USEC, SLOWCK_SW_TIME_USEC + 1);
if (system_state < SYSTEM_RUNNING)
udelay(SLOWCK_SW_TIME_USEC);
else
usleep_range(SLOWCK_SW_TIME_USEC, SLOWCK_SW_TIME_USEC + 1);
return 0;
}
@ -533,7 +542,10 @@ static int clk_sama5d4_slow_osc_prepare(struct clk_hw *hw)
return 0;
}
usleep_range(osc->startup_usec, osc->startup_usec + 1);
if (system_state < SYSTEM_RUNNING)
udelay(osc->startup_usec);
else
usleep_range(osc->startup_usec, osc->startup_usec + 1);
osc->prepared = true;
return 0;