From 8a5745e7e4ad8081d8340f71b372ca70ccc39434 Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Fri, 20 Sep 2019 17:39:06 +0200 Subject: [PATCH] clk: at91: avoid sleeping early MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit [ Upstream commit 658fd65cf0b0d511de1718e48d9a28844c385ae0 ] 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 Signed-off-by: Alexandre Belloni Link: https://lkml.kernel.org/r/20190920153906.20887-1-alexandre.belloni@bootlin.com Fixes: 80eded6ce8bb ("clk: at91: add slow clks driver") Tested-by: Uwe Kleine-König Signed-off-by: Stephen Boyd Signed-off-by: Sasha Levin --- 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 2f97a84..fb5c14a 100644 --- a/drivers/clk/at91/clk-main.c +++ b/drivers/clk/at91/clk-main.c @@ -354,7 +354,10 @@ 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; diff --git a/drivers/clk/at91/sckc.c b/drivers/clk/at91/sckc.c index ab6ecef..43ba2a8 100644 --- a/drivers/clk/at91/sckc.c +++ b/drivers/clk/at91/sckc.c @@ -74,7 +74,10 @@ static int clk_slow_osc_prepare(struct clk_hw *hw) 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; } @@ -197,7 +200,10 @@ static int clk_slow_rc_osc_prepare(struct clk_hw *hw) 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; } @@ -310,7 +316,10 @@ 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; } @@ -443,7 +452,10 @@ 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; -- 2.7.4