lkml.org 
[lkml]   [2018]   [Jul]   [27]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.17 12/66] clk: meson-gxbb: set fclk_div2 as CLK_IS_CRITICAL
Date
4.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Neil Armstrong <narmstrong@baylibre.com>

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@baylibre.com>
Tested-by: Kevin Hilman <khilman@baylibre.com>
[few corrections in the commit description]
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
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,
},
};


\
 
 \ /
  Last update: 2018-07-27 11:55    [W:0.176 / U:0.832 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site