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@xxxxxxxxxxx>
---
drivers/clk/samsung/clk-exynos4.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/clk/samsung/clk-exynos4.c b/drivers/clk/samsung/clk-exynos4.c
index 436fcd279951..bf13e29a655c 100644
--- a/drivers/clk/samsung/clk-exynos4.c
+++ b/drivers/clk/samsung/clk-exynos4.c
@@ -927,7 +927,7 @@ 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,
@@ -969,7 +969,7 @@ 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,
--
2.17.1
