[PATCH v3 2/6] OPP: Add support for bandwidth OPP tables

Saravana Kannan
2019-07-03T01:10:34Z

Not all devices quantify their performance points in terms of frequency.
Devices like interconnects quantify their performance points in terms of
bandwidth. We need a way to represent these bandwidth levels in OPP. So,
add support for parsing bandwidth OPPs from DT.

Signed-off-by: Saravana Kannan <saravanak@google.com>
---
drivers/opp/of.c | 34 ++++++++++++++++++++++++++++++++--
drivers/opp/opp.h | 4 +++-
2 files changed, 35 insertions(+), 3 deletions(-)

diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index c10c782d15aa..54fa70ed2adc 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -552,6 +552,35 @@ void dev_pm_opp_of_remove_table(struct device *dev)
}
EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);

+static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np)
+{
+ int ret;
+ u64 rate;
+ u32 bw;
+
+ ret = of_property_read_u64(np, "opp-hz", &rate);
+ if (!ret) {
+ /*
+ * Rate is defined as an unsigned long in clk API, and so
+ * casting explicitly to its type. Must be fixed once rate is 64
+ * bit guaranteed in clk API.
+ */
+ new_opp->rate = (unsigned long)rate;
+ return 0;
+ }
+
+ ret = of_property_read_u32(np, "opp-peak-KBps", &bw);
+ if (ret)
+ return ret;
+ new_opp->rate = (unsigned long) &bw;
+
+ ret = of_property_read_u32(np, "opp-avg-KBps", &bw);
+ if (!ret)
+ new_opp->avg_bw = (unsigned long) &bw;
+
+ return 0;
+}
+
/**
* _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
* @opp_table: OPP table
@@ -589,11 +618,12 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
if (!new_opp)
return ERR_PTR(-ENOMEM);

- ret = of_property_read_u64(np, "opp-hz", &rate);
+ ret = _read_opp_key(new_opp, np);
if (ret < 0) {
/* "opp-hz" is optional for devices like power domains. */
if (!opp_table->is_genpd) {
- dev_err(dev, "%s: opp-hz not found\n", __func__);
+ dev_err(dev, "%s: opp-hz or opp-peak-bw not found\n",
+ __func__);
goto free_opp;
}

diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index 569b3525aa67..ead2cdafe957 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -59,7 +59,8 @@ extern struct list_head opp_tables;
* @turbo: true if turbo (boost) OPP
* @suspend: true if suspend OPP
* @pstate: Device's power domain's performance state.
- * @rate: Frequency in hertz
+ * @rate: Frequency in hertz OR Peak bandwidth in kilobytes per second
+ * @avg_bw: Average bandwidth in kilobytes per second
* @level: Performance level
* @supplies: Power supplies voltage/current values
* @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
@@ -81,6 +82,7 @@ struct dev_pm_opp {
bool suspend;
unsigned int pstate;
unsigned long rate;
+ unsigned long avg_bw;
unsigned int level;

struct dev_pm_opp_supply *supplies;
--
2.22.0.410.gd8fdbe21b5-goog