3.16.80-rc1 review patch. If anyone has any objections, please let me know.
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From: Alexandre Belloni alexandre.belloni@bootlin.com
commit 658fd65cf0b0d511de1718e48d9a28844c385ae0 upstream.
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.c... Fixes: 80eded6ce8bb ("clk: at91: add slow clks driver") Tested-by: Uwe Kleine-König u.kleine-koenig@pengutronix.de Signed-off-by: Stephen Boyd sboyd@kernel.org [bwh: Backported to 3.16: - Drop changes in clk_sama5d4_slow_osc_prepare() - Adjust filename, context] Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/clk/at91/clk-main.c | 5 ++++- drivers/clk/at91/clk-slow.c | 20 ++++++++++++++++---- 2 files changed, 20 insertions(+), 5 deletions(-)
--- a/drivers/clk/at91/clk-main.c +++ b/drivers/clk/at91/clk-main.c @@ -374,7 +374,10 @@ static int clk_main_probe_frequency(stru tmp = pmc_read(pmc, AT91_CKGR_MCFR); if (tmp & 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; --- a/drivers/clk/at91/clk-slow.c +++ b/drivers/clk/at91/clk-slow.c @@ -83,7 +83,10 @@ static int clk_slow_osc_prepare(struct c
writel(tmp | AT91_SCKC_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; } @@ -202,7 +205,10 @@ static int clk_slow_rc_osc_prepare(struc
writel(readl(sckcr) | AT91_SCKC_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; } @@ -311,7 +317,10 @@ static int clk_sam9x5_slow_set_parent(st
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; }