lkml.org 
[lkml]   [2023]   [Jan]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v11 06/11] cpufreq: amd-pstate: implement suspend and resume callbacks
From


On 1/18/2023 1:22 PM, Perry Yuan wrote:
> From: Perry Yuan <Perry.Yuan@amd.com>
>
> add suspend and resume support for the AMD processors by amd_pstate_epp
> driver instance.
>
> When the CPPC is suspended, EPP driver will set EPP profile to 'power'
> profile and set max/min perf to lowest perf value.
> When resume happens, it will restore the MSR registers with
> previous cached value.
>
> Acked-by: Huang Rui <ray.huang@amd.com>
> Tested-by: Wyes Karny <wyes.karny@amd.com>
> Reviewed-by: Mario Limonciello <Mario.Limonciello@amd.com>
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>

Reviewed-by: <wyes.karny@amd.com>

> ---
> drivers/cpufreq/amd-pstate.c | 40 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 40 insertions(+)
>
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index 1472a6382b29..9e1bee060597 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -1045,6 +1045,44 @@ static int amd_pstate_epp_verify_policy(struct cpufreq_policy_data *policy)
> return 0;
> }
>
> +static int amd_pstate_epp_suspend(struct cpufreq_policy *policy)
> +{
> + struct amd_cpudata *cpudata = policy->driver_data;
> + int ret;
> +
> + /* avoid suspending when EPP is not enabled */
> + if (cppc_state != AMD_PSTATE_ACTIVE)
> + return 0;
> +
> + /* set this flag to avoid setting core offline*/
> + cpudata->suspended = true;
> +
> + /* disable CPPC in lowlevel firmware */
> + ret = amd_pstate_enable(false);
> + if (ret)
> + pr_err("failed to suspend, return %d\n", ret);
> +
> + return 0;
> +}
> +
> +static int amd_pstate_epp_resume(struct cpufreq_policy *policy)
> +{
> + struct amd_cpudata *cpudata = policy->driver_data;
> +
> + if (cpudata->suspended) {
> + mutex_lock(&amd_pstate_limits_lock);
> +
> + /* enable amd pstate from suspend state*/
> + amd_pstate_epp_reenable(cpudata);
> +
> + mutex_unlock(&amd_pstate_limits_lock);
> +
> + cpudata->suspended = false;
> + }
> +
> + return 0;
> +}
> +
> static struct cpufreq_driver amd_pstate_driver = {
> .flags = CPUFREQ_CONST_LOOPS | CPUFREQ_NEED_UPDATE_LIMITS,
> .verify = amd_pstate_verify,
> @@ -1066,6 +1104,8 @@ static struct cpufreq_driver amd_pstate_epp_driver = {
> .exit = amd_pstate_epp_cpu_exit,
> .offline = amd_pstate_epp_cpu_offline,
> .online = amd_pstate_epp_cpu_online,
> + .suspend = amd_pstate_epp_suspend,
> + .resume = amd_pstate_epp_resume,
> .name = "amd_pstate_epp",
> .attr = amd_pstate_epp_attr,
> };

--
Thanks & Regards,
Wyes

\
 
 \ /
  Last update: 2023-03-26 23:47    [W:0.300 / U:1.336 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site