firmware: arm_scmi: Add fast_switch_possible() interface

Add a new fast_switch_possible interface to the existing perf_ops to
export the information of whether or not fast_switch is possible for a
given device.

This can be used by the cpufreq driver and framework to choose proper
mechanism for frequency change.

Link: https://lore.kernel.org/r/20200617094332.8391-1-nicola.mazzucato@arm.com
Suggested-by: Lukasz Luba <lukasz.luba@arm.com>
Signed-off-by: Nicola Mazzucato <nicola.mazzucato@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index eadc171e254b85f8d0fa6b42a94fba33f9e3146a..7b8d7cebdac9fddfa66c12fb8641ed31840d73e5 100644 (file)
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -697,6 +697,17 @@ static int scmi_dvfs_est_power_get(const struct scmi_handle *handle, u32 domain,
        return ret;
 }
 
+static bool scmi_fast_switch_possible(const struct scmi_handle *handle,
+                                     struct device *dev)
+{
+       struct perf_dom_info *dom;
+       struct scmi_perf_info *pi = handle->perf_priv;
+
+       dom = pi->dom_info + scmi_dev_domain_id(dev);
+
+       return dom->fc_info && dom->fc_info->level_set_addr;
+}
+
 static struct scmi_perf_ops perf_ops = {
        .limits_set = scmi_perf_limits_set,
        .limits_get = scmi_perf_limits_get,
@@ -708,6 +719,7 @@ static struct scmi_perf_ops perf_ops = {
        .freq_set = scmi_dvfs_freq_set,
        .freq_get = scmi_dvfs_freq_get,
        .est_power_get = scmi_dvfs_est_power_get,
+       .fast_switch_possible = scmi_fast_switch_possible,
 };
 
 static int scmi_perf_protocol_init(struct scmi_handle *handle)

diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
index ce2f5c28b2dfd60b7aab4670df1eba7660141376..73911d156a39c76c7ad4ff8fc8d3488f67fca401 100644 (file)
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -118,6 +118,8 @@ struct scmi_perf_ops {
                        unsigned long *rate, bool poll);
        int (*est_power_get)(const struct scmi_handle *handle, u32 domain,
                             unsigned long *rate, unsigned long *power);
+       bool (*fast_switch_possible)(const struct scmi_handle *handle,
+                                    struct device *dev);
 };
 
 /**