From: Paweł Chmiel pawel.mikolaj.chmiel@gmail.com
commit 34138a59b92c1a30649a18ec442d2e61f3bc34dd upstream.
This clock must be always enabled to allow access to any registers in fsys1 CMU. Until proper solution based on runtime PM is applied (similar to what was done for Exynos5433), mark that clock as critical so it won't be disabled.
It was observed on Samsung Galaxy S6 device (based on Exynos7420), where UFS module is probed before pmic used to power that device. In this case defer probe was happening and that clock was disabled by UFS driver, causing whole boot to hang on next CMU access.
Fixes: 753195a749a6 ("clk: samsung: exynos7: Correct CMU_FSYS1 clocks names") Signed-off-by: Paweł Chmiel pawel.mikolaj.chmiel@gmail.com Acked-by: Krzysztof Kozlowski krzk@kernel.org Link: https://lore.kernel.org/linux-clk/20201024154346.9589-1-pawel.mikolaj.chmiel... [s.nawrocki: Added comment in the code] Signed-off-by: Sylwester Nawrocki s.nawrocki@samsung.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Yang Yingliang yangyingliang@huawei.com --- drivers/clk/samsung/clk-exynos7.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-)
diff --git a/drivers/clk/samsung/clk-exynos7.c b/drivers/clk/samsung/clk-exynos7.c index 492d516910800..9b02980ee929b 100644 --- a/drivers/clk/samsung/clk-exynos7.c +++ b/drivers/clk/samsung/clk-exynos7.c @@ -541,8 +541,13 @@ static const struct samsung_gate_clock top1_gate_clks[] __initconst = { GATE(CLK_ACLK_FSYS0_200, "aclk_fsys0_200", "dout_aclk_fsys0_200", ENABLE_ACLK_TOP13, 28, CLK_SET_RATE_PARENT | CLK_IS_CRITICAL, 0), + /* + * This clock is required for the CMU_FSYS1 registers access, keep it + * enabled permanently until proper runtime PM support is added. + */ GATE(CLK_ACLK_FSYS1_200, "aclk_fsys1_200", "dout_aclk_fsys1_200", - ENABLE_ACLK_TOP13, 24, CLK_SET_RATE_PARENT, 0), + ENABLE_ACLK_TOP13, 24, CLK_SET_RATE_PARENT | + CLK_IS_CRITICAL, 0),
GATE(CLK_SCLK_PHY_FSYS1_26M, "sclk_phy_fsys1_26m", "dout_sclk_phy_fsys1_26m", ENABLE_SCLK_TOP1_FSYS11,