Re: [PATCH v7 4/7] OPP: Add support for parsing interconnect bandwidth

From: Sibi Sankar
Date: Mon May 04 2020 - 17:03:57 EST

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Hey Georgi,

Apart from the Matthias's comments
ran into a few issues during testing.

On 2020-04-24 21:24, Georgi Djakov wrote:

The OPP bindings now support bandwidth values, so add support to parse it
from device tree and store it into the new dev_pm_opp_icc_bw struct, which
is part of the dev_pm_opp.

Signed-off-by: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
---
v7:
* Addressed some review comments from Viresh and Sibi.
* Various other changes.

v2:
https://lore.kernel.org/linux-arm-msm/20190423132823.7915-4-georgi.djakov@xxxxxxxxxx/

drivers/opp/Kconfig | 1 +
drivers/opp/core.c | 16 +++++-
drivers/opp/of.c | 119 ++++++++++++++++++++++++++++++++++++++++-
drivers/opp/opp.h | 9 ++++
include/linux/pm_opp.h | 12 +++++
5 files changed, 153 insertions(+), 4 deletions(-)

diff --git a/drivers/opp/Kconfig b/drivers/opp/Kconfig
index 35dfc7e80f92..230d2b84436c 100644
--- a/drivers/opp/Kconfig
+++ b/drivers/opp/Kconfig
@@ -2,6 +2,7 @@
config PM_OPP
bool
select SRCU
+ depends on INTERCONNECT || !INTERCONNECT
---help---
SOCs have a standard set of tuples consisting of frequency and
voltage pairs that the device will support per voltage domain. This
diff --git a/drivers/opp/core.c b/drivers/opp/core.c
index c9c1bbe6ae27..8e86811eb7b2 100644
--- a/drivers/opp/core.c
+++ b/drivers/opp/core.c
@@ -985,6 +985,12 @@ static struct opp_table
*_allocate_opp_table(struct device *dev, int index)
ret);
}

+ /* Find interconnect path(s) for the device */
+ ret = _of_find_paths(opp_table, dev);
+ if (ret)
+ dev_dbg(dev, "%s: Error finding interconnect paths: %d\n",
+ __func__, ret);
+
BLOCKING_INIT_NOTIFIER_HEAD(&opp_table->head);
INIT_LIST_HEAD(&opp_table->opp_list);
kref_init(&opp_table->kref);
@@ -1229,19 +1235,22 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_remove_all_dynamic);
struct dev_pm_opp *_opp_allocate(struct opp_table *table)
{
struct dev_pm_opp *opp;
- int count, supply_size;
+ int count, supply_size, icc_size;

/* Allocate space for at least one supply */
count = table->regulator_count > 0 ? table->regulator_count : 1;
supply_size = sizeof(*opp->supplies) * count;
+ icc_size = sizeof(*opp->bandwidth) * table->path_count;

/* allocate new OPP node and supplies structures */
- opp = kzalloc(sizeof(*opp) + supply_size, GFP_KERNEL);
+ opp = kzalloc(sizeof(*opp) + supply_size + icc_size, GFP_KERNEL);
+
if (!opp)
return NULL;

/* Put the supplies at the end of the OPP structure as an empty array */
opp->supplies = (struct dev_pm_opp_supply *)(opp + 1);
+ opp->bandwidth = (struct dev_pm_opp_icc_bw *)(opp->supplies + 1);
INIT_LIST_HEAD(&opp->node);

return opp;
@@ -1276,6 +1285,9 @@ int _opp_compare_key(struct dev_pm_opp *opp1,
struct dev_pm_opp *opp2)
{
if (opp1->rate != opp2->rate)
return opp1->rate < opp2->rate ? -1 : 1;
+ if (opp1->bandwidth && opp2->bandwidth &&
+ opp1->bandwidth[0].peak != opp2->bandwidth[0].peak)
+ return opp1->bandwidth[0].peak < opp2->bandwidth[0].peak ? -1 : 1;
if (opp1->level != opp2->level)
return opp1->level < opp2->level ? -1 : 1;
return 0;
diff --git a/drivers/opp/of.c b/drivers/opp/of.c
index e33169c7e045..978e445b0cdb 100644
--- a/drivers/opp/of.c
+++ b/drivers/opp/of.c
@@ -332,6 +332,59 @@ static int _of_opp_alloc_required_opps(struct
opp_table *opp_table,
return ret;
}

+int _of_find_paths(struct opp_table *opp_table, struct device *dev)
+{
+ struct device_node *np;
+ int ret, i, count, num_paths;
+
+ np = of_node_get(dev->of_node);
+ if (!np)
+ return 0;
+
+ count = of_count_phandle_with_args(np, "interconnects",
+ "#interconnect-cells");
+ of_node_put(np);
+ if (count < 0)
+ return 0;
+
+ /* two phandles when #interconnect-cells = <1> */
+ if (count % 2) {
+ dev_err(dev, "%s: Invalid interconnects values\n",
+ __func__);
+ return -EINVAL;
+ }
+
+ num_paths = count / 2;
+ opp_table->paths = kcalloc(num_paths, sizeof(*opp_table->paths),
+ GFP_KERNEL);
+ if (!opp_table->paths)
+ return -ENOMEM;
+
+ for (i = 0; i < num_paths; i++) {
+ opp_table->paths[i] = of_icc_get_by_index(dev, i);

now that icc_get is part of the
opp core framework shouldn't we
do a put on table remove as well?

+ if (IS_ERR(opp_table->paths[i])) {
+ ret = PTR_ERR(opp_table->paths[i]);
+ if (ret != -EPROBE_DEFER) {
+ dev_err(dev, "%s: Unable to get path%d: %d\n",
+ __func__, i, ret);
+ }
+ goto err;
+ }
+ }
+ opp_table->path_count = num_paths;
+
+ return 0;
+
+err:
+ while (i--)
+ icc_put(opp_table->paths[i]);
+
+ kfree(opp_table->paths);
+ opp_table->paths = NULL;
+
+ return ret;
+}
+
static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
struct device_node *np)
{
@@ -524,8 +577,11 @@ EXPORT_SYMBOL_GPL(dev_pm_opp_of_remove_table);
static int _read_opp_key(struct dev_pm_opp *new_opp, struct device_node *np,
bool *rate_not_available)
{
+ struct property *peak, *avg;
+ u32 *peak_bw, *avg_bw;
u64 rate;
- int ret;
+ int ret, i, count;
+ bool found = false;

ret = of_property_read_u64(np, "opp-hz", &rate);
if (!ret) {
@@ -535,10 +591,69 @@ static int _read_opp_key(struct dev_pm_opp
*new_opp, struct device_node *np,
* bit guaranteed in clk API.
*/
new_opp->rate = (unsigned long)rate;
+ found = true;
}
*rate_not_available = !!ret;

- of_property_read_u32(np, "opp-level", &new_opp->level);
+ peak = of_find_property(np, "opp-peak-kBps", NULL);
+ if (peak) {
+ /*
+ * Bandwidth consists of peak and average (optional) values:
+ * opp-peak-kBps = <path1_value path2_value>;
+ * opp-avg-kBps = <path1_value path2_value>;
+ */
+ count = peak->length / sizeof(u32);
+ peak_bw = kmalloc_array(count, sizeof(*peak_bw), GFP_KERNEL);
+ if (!peak_bw)
+ return -ENOMEM;
+
+ ret = of_property_read_u32_array(np, "opp-peak-kBps", peak_bw,
+ count);
+ if (ret) {
+ pr_err("%s: Error parsing opp-peak-kBps: %d\n",
+ __func__, ret);
+ goto free_peak_bw;
+ }
+
+ for (i = 0; i < count; i++)
+ new_opp->bandwidth[i].peak = kBps_to_icc(peak_bw[i]);
+
+ found = true;
+ }
+
+ avg = of_find_property(np, "opp-avg-kBps", NULL);
+ if (peak && avg) {
+ count = avg->length / sizeof(u32);
+ avg_bw = kmalloc_array(count, sizeof(*avg_bw), GFP_KERNEL);
+ if (!avg_bw) {
+ ret = -ENOMEM;
+ goto free_peak_bw;
+ }
+
+ ret = of_property_read_u32_array(np, "opp-avg-kBps", avg_bw,
+ count);
+ if (ret) {
+ pr_err("%s: Error parsing opp-avg-kBps: %d\n",
+ __func__, ret);
+ goto free_avg_bw;
+ }
+
+ for (i = 0; i < count; i++)
+ new_opp->bandwidth[i].avg = kBps_to_icc(avg_bw[i]);
+ }
+
+ if (of_property_read_u32(np, "opp-level", &new_opp->level))

of_property_read_u32 returns 0 on
success so should use logical not
instead ^^

+ found = true;
+
+ if (found)
+ return 0;
+
+ return ret;
+
+free_avg_bw:
+ kfree(avg_bw);
+free_peak_bw:
+ kfree(peak_bw);

return ret;
}
diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
index bcadb1e328a4..2e0113360297 100644
--- a/drivers/opp/opp.h
+++ b/drivers/opp/opp.h
@@ -12,6 +12,7 @@
#define __DRIVER_OPP_H__

#include <linux/device.h>
+#include <linux/interconnect.h>
#include <linux/kernel.h>
#include <linux/kref.h>
#include <linux/list.h>
@@ -59,6 +60,7 @@ extern struct list_head opp_tables;
* @rate: Frequency in hertz
* @level: Performance level
* @supplies: Power supplies voltage/current values
+ * @bandwidth: Interconnect bandwidth values
* @clock_latency_ns: Latency (in nanoseconds) of switching to this OPP's
* frequency from any other OPP's frequency.
* @required_opps: List of OPPs that are required by this OPP.
@@ -81,6 +83,7 @@ struct dev_pm_opp {
unsigned int level;

struct dev_pm_opp_supply *supplies;
+ struct dev_pm_opp_icc_bw *bandwidth;

unsigned long clock_latency_ns;

@@ -146,6 +149,8 @@ enum opp_table_access {
* @regulator_count: Number of power supply regulators. Its value can be -1
* (uninitialized), 0 (no opp-microvolt property) or > 0 (has opp-microvolt
* property).
+ * @paths: Interconnect path handles
+ * @path_count: Number of interconnect paths
* @genpd_performance_state: Device's power domain support performance state.
* @is_genpd: Marks if the OPP table belongs to a genpd.
* @set_opp: Platform specific set_opp callback
@@ -189,6 +194,8 @@ struct opp_table {
struct clk *clk;
struct regulator **regulators;
int regulator_count;
+ struct icc_path **paths;
+ unsigned int path_count;
bool genpd_performance_state;
bool is_genpd;

@@ -224,12 +231,14 @@ void _of_clear_opp_table(struct opp_table *opp_table);
struct opp_table *_managed_opp(struct device *dev, int index);
void _of_opp_free_required_opps(struct opp_table *opp_table,
struct dev_pm_opp *opp);
+int _of_find_paths(struct opp_table *opp_table, struct device *dev);
#else
static inline void _of_init_opp_table(struct opp_table *opp_table,
struct device *dev, int index) {}
static inline void _of_clear_opp_table(struct opp_table *opp_table) {}
static inline struct opp_table *_managed_opp(struct device *dev, int
index) { return NULL; }
static inline void _of_opp_free_required_opps(struct opp_table *opp_table,
struct dev_pm_opp *opp) {}
+static inline int _of_find_paths(struct opp_table *opp_table, struct
device *dev) { return 0; }
#endif

#ifdef CONFIG_DEBUG_FS
diff --git a/include/linux/pm_opp.h b/include/linux/pm_opp.h
index 747861816f4f..cfceb0290401 100644
--- a/include/linux/pm_opp.h
+++ b/include/linux/pm_opp.h
@@ -41,6 +41,18 @@ struct dev_pm_opp_supply {
unsigned long u_amp;
};

+/**
+ * struct dev_pm_opp_icc_bw - Interconnect bandwidth values
+ * @avg: Average bandwidth corresponding to this OPP (in icc units)
+ * @peak: Peak bandwidth corresponding to this OPP (in icc units)
+ *
+ * This structure stores the bandwidth values for a single interconnect path.
+ */
+struct dev_pm_opp_icc_bw {
+ u32 avg;
+ u32 peak;
+};
+
/**
* struct dev_pm_opp_info - OPP freq/voltage/current values
* @rate: Target clk rate in hz

--
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a Linux Foundation Collaborative Project.

Next message: Will Deacon: "Re: [PATCH] arm64/cpuinfo: Move device_initcall() near cpuinfo_regs_init()"
Previous message: Florian Fainelli: "Re: [PATCH net] net: dsa: Do not leave DSA master with NULL netdev_ops"
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