clk: meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL

superna9999 · jbrun3t · commit c987ac6f1f08 · 2018-06-19T17:20:11.000+02:00
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 05f8144 ("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: 05f8144 ("clk: meson: add fdiv clock gates") Signed-off-by: Neil Armstrong <narmstrong@baylibre.com> Tested-by: Kevin Hilman <khilman@baylibre.com> [few corrections in the commit description] Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
diff --git a/drivers/clk/meson/gxbb.c b/drivers/clk/meson/gxbb.c
@@ -498,6 +498,7 @@ 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,
 	},
 };
 
