firmware: arm_scmi: add a getter for power of performance states

The SCMI protocol can be used to get power estimates from firmware
corresponding to each performance state of a device. Although these power
costs are already managed by the SCMI firmware driver, they are not
exposed to any external subsystem yet.

Fix this by adding a new get_power() interface to the exisiting perf_ops
defined for the SCMI protocol.

Signed-off-by: Quentin Perret <quentin.perret@arm.com>
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>

2 files changed, 32 insertions, 0 deletions

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 87c99d296ecd..3c8ae7cc35de 100644
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -427,6 +427,33 @@ static int scmi_dvfs_freq_get(const struct scmi_handle *handle, u32 domain,
         return ret;
 }
 
+static int scmi_dvfs_est_power_get(const struct scmi_handle *handle, u32 domain,
+                                   unsigned long *freq, unsigned long *power)
+{
+        struct scmi_perf_info *pi = handle->perf_priv;
+        struct perf_dom_info *dom;
+        unsigned long opp_freq;
+        int idx, ret = -EINVAL;
+        struct scmi_opp *opp;
+
+        dom = pi->dom_info + domain;
+        if (!dom)
+                return -EIO;
+
+        for (opp = dom->opp, idx = 0; idx < dom->opp_count; idx++, opp++) {
+                opp_freq = opp->perf * dom->mult_factor;
+                if (opp_freq < *freq)
+                        continue;
+
+                *freq = opp_freq;
+                *power = opp->power;
+                ret = 0;
+                break;
+        }
+
+        return ret;
+}
+
 static struct scmi_perf_ops perf_ops = {
         .limits_set = scmi_perf_limits_set,
         .limits_get = scmi_perf_limits_get,
@@ -437,6 +464,7 @@ static struct scmi_perf_ops perf_ops = {
         .device_opps_add = scmi_dvfs_device_opps_add,
         .freq_set = scmi_dvfs_freq_set,
         .freq_get = scmi_dvfs_freq_get,
+        .est_power_get = scmi_dvfs_est_power_get,
 };
 
 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 f4c9fc0fc755..3105055c00a7 100644
--- a/include/linux/scmi_protocol.h
+++ b/include/linux/scmi_protocol.h
@@ -91,6 +91,8 @@ struct scmi_clk_ops {
  *      to sustained performance level mapping
  * @freq_get: gets the frequency for a given device using sustained frequency
  *      to sustained performance level mapping
+ * @est_power_get: gets the estimated power cost for a given performance domain
+ *      at a given frequency
  */
 struct scmi_perf_ops {
         int (*limits_set)(const struct scmi_handle *handle, u32 domain,
@@ -110,6 +112,8 @@ struct scmi_perf_ops {
                         unsigned long rate, bool poll);
         int (*freq_get)(const struct scmi_handle *handle, u32 domain,
                         unsigned long *rate, bool poll);
+        int (*est_power_get)(const struct scmi_handle *handle, u32 domain,
+                             unsigned long *rate, unsigned long *power);
 };
 
 /**