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Subject[PATCH v3] firmware: arm_scmi: add a getter for power of performance states
Date
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>
---
v3: Changed the accessor name to "scmi_dvfs_est_power_get"
v2: rebased on 4.19-rc2
---
drivers/firmware/arm_scmi/perf.c | 28 ++++++++++++++++++++++++++++
include/linux/scmi_protocol.h | 4 ++++
2 files changed, 32 insertions(+)

diff --git a/drivers/firmware/arm_scmi/perf.c b/drivers/firmware/arm_scmi/perf.c
index 721e6c57beae..3e6453b4ea1d 100644
--- a/drivers/firmware/arm_scmi/perf.c
+++ b/drivers/firmware/arm_scmi/perf.c
@@ -421,6 +421,33 @@ 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,
@@ -431,6 +458,7 @@ 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..e4db899c1cfb 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);
};

/**
--
2.17.1
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