4.17-stable review patch. If anyone has any objections, please let me know.
------------------
From: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
commit c987ac6f1f088663b6dad39281071aeb31d450a8 upstream.
On Amlogic Meson GXBB & GXL platforms, the SCPI Cortex-M4 Co-Processor
seems to be dependent on the FCLK_DIV2 to be operationnal.
The issue occurred since v4.17-rc1 by freezing the kernel boot when
the 'schedutil' cpufreq governor was selected as default :
[ 12.071837] scpi_protocol scpi: SCP Protocol 0.0 Firmware 0.0.0 version
domain-0 init dvfs: 4
[ 12.087757] hctosys: unable to open rtc device (rtc0)
[ 12.087907] cfg80211: Loading compiled-in X.509 certificates for regulatory database
[ 12.102241] cfg80211: Loaded X.509 cert 'sforshee: 00b28ddf47aef9cea7'
But when disabling the MMC driver, the boot finished but cpufreq failed to
change the CPU frequency :
[ 12.153045] cpufreq: __target_index: Failed to change cpu frequency: -5
A bisect between v4.16 and v4.16-rc1 gave
05f814402d61 ("clk: meson: add fdiv clock gates") to be the first bad commit.
This commit added support for the missing clock gates before the fixed PLL
fixed dividers (FCLK_DIVx) and the clock framework basically disabled
all the unused fixed dividers, thus disabled a critical clock path for
the SCPI Co-Processor.
This patch simply sets the FCLK_DIV2 gate as critical to ensure
nobody can disable it.
Fixes: 05f814402d61 ("clk: meson: add fdiv clock gates")
Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
Tested-by: Kevin Hilman <khilman@xxxxxxxxxxxx>
[few corrections in the commit description]
Signed-off-by: Jerome Brunet <jbrunet@xxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/clk/meson/gxbb.c | 1 +
1 file changed, 1 insertion(+)
--- a/drivers/clk/meson/gxbb.c
+++ b/drivers/clk/meson/gxbb.c
@@ -511,6 +511,7 @@ static struct clk_regmap gxbb_fclk_div2
.ops = &clk_regmap_gate_ops,
.parent_names = (const char *[]){ "fclk_div2_div" },
.num_parents = 1,
+ .flags = CLK_IS_CRITICAL,
},
};
