[PATCH 5.0 81/95] cpufreq: armada-37xx: fix frequency calculation for opp

Greg Kroah-Hartman
2019-05-09T18:53:13Z

From: Gregory CLEMENT <gregory.clement@bootlin.com>

commit 8db82563451f976597ab7b282ec655e4390a4088 upstream.

The frequency calculation was based on the current(max) frequency of the
CPU. However for low frequency, the value used was already the parent
frequency divided by a factor of 2.

Instead of using this frequency, this fix directly get the frequency from
the parent clock.

Fixes: 92ce45fb875d ("cpufreq: Add DVFS support for Armada 37xx")
Cc: <stable@vger.kernel.org>
Reported-by: Christian Neubert <christian.neubert.86@gmail.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@bootlin.com>
Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/cpufreq/armada-37xx-cpufreq.c | 22 +++++++++++++++++++---
1 file changed, 19 insertions(+), 3 deletions(-)

--- a/drivers/cpufreq/armada-37xx-cpufreq.c
+++ b/drivers/cpufreq/armada-37xx-cpufreq.c
@@ -359,11 +359,11 @@ static int __init armada37xx_cpufreq_dri
struct armada_37xx_dvfs *dvfs;
struct platform_device *pdev;
unsigned long freq;
- unsigned int cur_frequency;
+ unsigned int cur_frequency, base_frequency;
struct regmap *nb_pm_base, *avs_base;
struct device *cpu_dev;
int load_lvl, ret;
- struct clk *clk;
+ struct clk *clk, *parent;

nb_pm_base =
syscon_regmap_lookup_by_compatible("marvell,armada-3700-nb-pm");
@@ -399,6 +399,22 @@ static int __init armada37xx_cpufreq_dri
return PTR_ERR(clk);
}

+ parent = clk_get_parent(clk);
+ if (IS_ERR(parent)) {
+ dev_err(cpu_dev, "Cannot get parent clock for CPU0\n");
+ clk_put(clk);
+ return PTR_ERR(parent);
+ }
+
+ /* Get parent CPU frequency */
+ base_frequency = clk_get_rate(parent);
+
+ if (!base_frequency) {
+ dev_err(cpu_dev, "Failed to get parent clock rate for CPU\n");
+ clk_put(clk);
+ return -EINVAL;
+ }
+
/* Get nominal (current) CPU frequency */
cur_frequency = clk_get_rate(clk);
if (!cur_frequency) {
@@ -431,7 +447,7 @@ static int __init armada37xx_cpufreq_dri
for (load_lvl = ARMADA_37XX_DVFS_LOAD_0; load_lvl < LOAD_LEVEL_NR;
load_lvl++) {
unsigned long u_volt = avs_map[dvfs->avs[load_lvl]] * 1000;
- freq = cur_frequency / dvfs->divider[load_lvl];
+ freq = base_frequency / dvfs->divider[load_lvl];
ret = dev_pm_opp_add(cpu_dev, freq, u_volt);
if (ret)
goto remove_opp;