On 08-03-19, 17:47, Gregory CLEMENT wrote:
> 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@xxxxxxxxxxxxxxx>
> Reported-by: Christian Neubert <christian.neubert.86@xxxxxxxxx>
> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxx>
> ---
> drivers/cpufreq/armada-37xx-cpufreq.c | 22 +++++++++++++++++++---
> 1 file changed, 19 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/cpufreq/armada-37xx-cpufreq.c b/drivers/cpufreq/armada-37xx-cpufreq.c
> index ad4463e4266e..a0962463805e 100644
> --- a/drivers/cpufreq/armada-37xx-cpufreq.c
> +++ b/drivers/cpufreq/armada-37xx-cpufreq.c
> @@ -373,11 +373,11 @@ static int __init armada37xx_cpufreq_driver_init(void)
> 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");
> @@ -413,6 +413,22 @@ static int __init armada37xx_cpufreq_driver_init(void)
> 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) {
> @@ -445,7 +461,7 @@ static int __init armada37xx_cpufreq_driver_init(void)
> 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;
Great. I was wondering on why the top frequency was skipped :)
--
viresh
