Re: [PATCH V2 13/15] cpufreq: mediatek: Link CCI device to CPU

AngeloGioacchino Del Regno
2022-04-08T13:37:52Z

Il 08/04/22 06:59, Rex-BC Chen ha scritto:
> From: Jia-Wei Chang <jia-wei.chang@mediatek.com>
>
> In some MediaTek SoCs, like MT8183, CPU and CCI share the same power
> supplies. Cpufreq needs to check if CCI devfreq exists and wait until
> CCI devfreq ready before scaling frequency.
>
> - Add is_ccifreq_ready() to link CCI device to CPI, and CPU will start
> DVFS when CCI is ready.
> - Add platform data for MT8183.
>
> Signed-off-by: Jia-Wei Chang <jia-wei.chang@mediatek.com>
> ---
> drivers/cpufreq/mediatek-cpufreq.c | 69 +++++++++++++++++++++++++++++-
> 1 file changed, 68 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/cpufreq/mediatek-cpufreq.c b/drivers/cpufreq/mediatek-cpufreq.c
> index b08ab7c14818..cebe5af2ef5d 100644
> --- a/drivers/cpufreq/mediatek-cpufreq.c
> +++ b/drivers/cpufreq/mediatek-cpufreq.c
> @@ -22,6 +22,7 @@ struct mtk_cpufreq_platform_data {
> int proc_max_volt;
> int sram_min_volt;
> int sram_max_volt;
> + bool is_ccifreq_support;

bool ccifreq_supported; looks better.

> };
>
> /*
> @@ -38,6 +39,7 @@ struct mtk_cpufreq_platform_data {
> struct mtk_cpu_dvfs_info {
> struct cpumask cpus;
> struct device *cpu_dev;
> + struct device *cci_dev;
> struct regulator *proc_reg;
> struct regulator *sram_reg;
> struct clk *cpu_clk;
> @@ -52,6 +54,7 @@ struct mtk_cpu_dvfs_info {
> int opp_cpu;
> unsigned long opp_freq;
> const struct mtk_cpufreq_platform_data *soc_data;
> + bool is_ccifreq_bounded;

bool ccifreq_bound; looks better.

> };
>
> static struct platform_device *cpufreq_pdev;
> @@ -171,6 +174,29 @@ static int mtk_cpufreq_set_voltage(struct mtk_cpu_dvfs_info *info, int vproc)
> return ret;
> }
>
> +static bool is_ccifreq_ready(struct mtk_cpu_dvfs_info *info)
> +{
> + struct device_link *sup_link;
> +
> + if (info->is_ccifreq_bounded)
> + return true;
> +
> + sup_link = device_link_add(info->cpu_dev, info->cci_dev,
> + DL_FLAG_AUTOREMOVE_CONSUMER);
> + if (!sup_link) {
> + dev_err(info->cpu_dev, "cpu%d: sup_link is NULL\n",
> + info->opp_cpu);

Please, don't break this line: 84 columns are ok.

> + return false;
> + }
> +
> + if (sup_link->supplier->links.status != DL_DEV_DRIVER_BOUND)
> + return false;
> +
> + info->is_ccifreq_bounded = true;
> +
> + return true;
> +}
> +
> static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> unsigned int index)
> {
> @@ -183,6 +209,9 @@ static int mtk_cpufreq_set_target(struct cpufreq_policy *policy,
> long freq_hz, old_freq_hz;
> int vproc, old_vproc, inter_vproc, target_vproc, ret;
>
> + if (info->soc_data->is_ccifreq_support && !is_ccifreq_ready(info))
> + return 0;

Honestly, I think that pretending that everything is alright and faking
set_target success is *not* a good idea...

You should return -EAGAIN here, not zero.

Regards,
Angelo