clk: samsung: exynos4: mark 'chipid' clock as CLK_IGNORE_UNUSED

[ Upstream commit f3bb0f796f5ffe32f0fbdce5b1b12eb85511158f ]

The ChipID IO region has it's own clock, which is being disabled while
scanning for unused clocks. It turned out that some CPU hotplug, CPU idle
or even SOC firmware code depends on the reads from that area. Fix the
mysterious hang caused by entering deep CPU idle state by ignoring the
'chipid' clock during unused clocks scan, as there are no direct clients
for it which will keep it enabled.

Fixes: e062b571777f ("clk: exynos4: register clocks using common clock framework")
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20200922124046.10496-1-m.szyprowski@samsung.com
Reviewed-by: Krzysztof Kozlowski <krzk@kernel.org>
Acked-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>

diff --git a/drivers/clk/samsung/clk-exynos4.c b/drivers/clk/samsung/clk-exynos4.c
index 91f9b79e39411abc79f151efd3245d1af32c8afe..9a9402f568ef6a0a3adb6541060fe33b7ae92fab 100644 (file)
--- a/drivers/clk/samsung/clk-exynos4.c
+++ b/drivers/clk/samsung/clk-exynos4.c
@@ -1060,7 +1060,7 @@ static const struct samsung_gate_clock exynos4210_gate_clks[] __initconst = {
        GATE(CLK_PCIE, "pcie", "aclk133", GATE_IP_FSYS, 14, 0, 0),
        GATE(CLK_SMMU_PCIE, "smmu_pcie", "aclk133", GATE_IP_FSYS, 18, 0, 0),
        GATE(CLK_MODEMIF, "modemif", "aclk100", GATE_IP_PERIL, 28, 0, 0),
-       GATE(CLK_CHIPID, "chipid", "aclk100", E4210_GATE_IP_PERIR, 0, 0, 0),
+       GATE(CLK_CHIPID, "chipid", "aclk100", E4210_GATE_IP_PERIR, 0, CLK_IGNORE_UNUSED, 0),
        GATE(CLK_SYSREG, "sysreg", "aclk100", E4210_GATE_IP_PERIR, 0,
                        CLK_IGNORE_UNUSED, 0),
        GATE(CLK_HDMI_CEC, "hdmi_cec", "aclk100", E4210_GATE_IP_PERIR, 11, 0,
@@ -1101,7 +1101,7 @@ static const struct samsung_gate_clock exynos4x12_gate_clks[] __initconst = {
                0),
        GATE(CLK_TSADC, "tsadc", "aclk133", E4X12_GATE_BUS_FSYS1, 16, 0, 0),
        GATE(CLK_MIPI_HSI, "mipi_hsi", "aclk133", GATE_IP_FSYS, 10, 0, 0),
-       GATE(CLK_CHIPID, "chipid", "aclk100", E4X12_GATE_IP_PERIR, 0, 0, 0),
+       GATE(CLK_CHIPID, "chipid", "aclk100", E4X12_GATE_IP_PERIR, 0, CLK_IGNORE_UNUSED, 0),
        GATE(CLK_SYSREG, "sysreg", "aclk100", E4X12_GATE_IP_PERIR, 1,
                        CLK_IGNORE_UNUSED, 0),
        GATE(CLK_HDMI_CEC, "hdmi_cec", "aclk100", E4X12_GATE_IP_PERIR, 11, 0,