Re: [PATCH v2 3/5] OPP: Add support for parsing the interconnect bandwidth

From: Viresh Kumar
Date: Wed Apr 24 2019 - 01:52:15 EST

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On 23-04-19, 16:28, 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.
>
> Also add and export the dev_pm_opp_set_paths() and dev_pm_opp_put_paths()
> helpers, to set (and release) an interconnect paths to a device. The
> bandwidth of these paths will be updated when the OPPs are switched.
>
> Signed-off-by: Georgi Djakov <georgi.djakov@xxxxxxxxxx>
> ---
> drivers/opp/core.c | 87 ++++++++++++++++++++++++++++++++++-
> drivers/opp/of.c | 102 +++++++++++++++++++++++++++++++++++++++++
> drivers/opp/opp.h | 9 ++++
> include/linux/pm_opp.h | 14 ++++++
> 4 files changed, 210 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/opp/core.c b/drivers/opp/core.c
> index 0420f7e8ad5b..97ee39ecdebd 100644
> --- a/drivers/opp/core.c
> +++ b/drivers/opp/core.c
> @@ -19,6 +19,7 @@
> #include <linux/slab.h>
> #include <linux/device.h>
> #include <linux/export.h>
> +#include <linux/interconnect.h>

Just include this once in opp.h and the other .c files won't need it.

> #include <linux/pm_domain.h>
> #include <linux/regulator/consumer.h>
>
> @@ -876,6 +877,8 @@ static struct opp_table *_allocate_opp_table(struct device *dev, int index)
> ret);
> }
>
> + _of_find_paths(opp_table, dev);
> +
> BLOCKING_INIT_NOTIFIER_HEAD(&opp_table->head);
> INIT_LIST_HEAD(&opp_table->opp_list);
> kref_init(&opp_table->kref);
> @@ -1129,11 +1132,12 @@ 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);

You never updated this to include icc_size :(

> @@ -1141,7 +1145,8 @@ struct dev_pm_opp *_opp_allocate(struct opp_table *table)
> 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 + 1);

Keep the order as supplies and then bandwidth.

> + opp->supplies = (struct dev_pm_opp_supply *)(opp + icc_size + 1);

Did you check what address gets assigned here ? I think the pointer
addition will screw things up for you.

> INIT_LIST_HEAD(&opp->node);
>
> return opp;
> @@ -1637,6 +1642,84 @@ void dev_pm_opp_put_clkname(struct opp_table *opp_table)
> }
> EXPORT_SYMBOL_GPL(dev_pm_opp_put_clkname);
>
> +/**
> + * dev_pm_opp_set_paths() - Set interconnect path for a device
> + * @dev: Device for which interconnect path is being set.
> + *
> + * This must be called before any OPPs are initialized for the device.
> + */
> +struct opp_table *dev_pm_opp_set_paths(struct device *dev)

I got a bit confused. Why is this routine required exactly as
_of_find_paths() would have already done something similar ?

> +{
> + struct opp_table *opp_table;
> + int ret, i;
> +
> + opp_table = dev_pm_opp_get_opp_table(dev);
> + if (!opp_table)
> + return ERR_PTR(-ENOMEM);
> +
> + /* This should be called before OPPs are initialized */
> + if (WARN_ON(!list_empty(&opp_table->opp_list))) {
> + ret = -EBUSY;
> + goto err;
> + }
> +
> + /* Another CPU that shares the OPP table has set the path */
> + if (opp_table->paths)
> + return opp_table;
> +
> + opp_table->paths = kmalloc_array(opp_table->path_count,
> + sizeof(*opp_table->paths), GFP_KERNEL);
> +
> + /* Find interconnect path(s) for the device */
> + for (i = 0; i < opp_table->path_count; i++) {
> + opp_table->paths[i] = of_icc_get_by_index(dev, i);
> + if (IS_ERR(opp_table->paths[i])) {
> + ret = PTR_ERR(opp_table->paths[i]);
> + if (ret != -EPROBE_DEFER)
> + dev_err(dev, "%s: Couldn't find path%d: %d\n",
> + __func__, i, ret);
> + goto err;
> + }
> + }
> +
> + return opp_table;
> +
> +err:
> + dev_pm_opp_put_opp_table(opp_table);
> +
> + return ERR_PTR(ret);
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_opp_set_paths);
> +
> +/**
> + * dev_pm_opp_put_paths() - Release interconnect path resources
> + * @opp_table: OPP table returned from dev_pm_opp_set_paths().
> + */
> +void dev_pm_opp_put_paths(struct opp_table *opp_table)
> +{
> + int i;
> +
> + if (!opp_table->paths) {
> + pr_err("%s: Doesn't have paths set\n", __func__);
> + return;
> + }
> +
> + /* Make sure there are no concurrent readers while updating opp_table */
> + WARN_ON(!list_empty(&opp_table->opp_list));
> +
> + for (i = opp_table->path_count - 1; i >= 0; i--)
> + icc_put(opp_table->paths[i]);
> +
> + _free_set_opp_data(opp_table);
> +
> + kfree(opp_table->paths);
> + opp_table->paths = NULL;
> + opp_table->path_count = 0;
> +
> + dev_pm_opp_put_opp_table(opp_table);
> +}
> +EXPORT_SYMBOL_GPL(dev_pm_opp_put_paths);
> +
> /**
> * dev_pm_opp_register_set_opp_helper() - Register custom set OPP helper
> * @dev: Device for which the helper is getting registered.
> diff --git a/drivers/opp/of.c b/drivers/opp/of.c
> index c10c782d15aa..00af23280bc6 100644
> --- a/drivers/opp/of.c
> +++ b/drivers/opp/of.c
> @@ -16,6 +16,7 @@
> #include <linux/cpu.h>
> #include <linux/errno.h>
> #include <linux/device.h>
> +#include <linux/interconnect.h>
> #include <linux/of_device.h>
> #include <linux/pm_domain.h>
> #include <linux/slab.h>
> @@ -363,6 +364,45 @@ 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) {

I would rather do:

if (!np)
return 0;

That will kill unnecessary line breaks and indentation.

> + count = of_count_phandle_with_args(np, "interconnects",
> + "#interconnect-cells");

You can do of_node_put() right here as it isn't used afterwards.

> + if (count % 2) {

Shouldn't this be 4 instead of 2 ? Each path is represented as:

<&noc MASTER_CPU &noc SLAVE_DDR>

which has 4 fields.

> + dev_err(dev, "%s: Invalid interconnects values\n",
> + __func__);
> + ret = -EINVAL;
> + goto put_of_node;
> + }
> +
> + num_paths = count / 2;
> + opp_table->paths = kcalloc(num_paths, sizeof(*opp_table->paths),
> + GFP_KERNEL);
> + if (!opp_table->paths) {
> + ret = -ENOMEM;
> + goto put_of_node;
> + }
> +
> + for (i = 0; i < num_paths; i++)
> + opp_table->paths[i] = of_icc_get_by_index(dev, i);
> +
> + opp_table->path_count = num_paths;
> + of_node_put(np);
> + }
> +
> + return 0;
> +
> +put_of_node:
> + of_node_put(np);
> +
> + return ret;
> +}
> +
> static bool _opp_is_supported(struct device *dev, struct opp_table *opp_table,
> struct device_node *np)
> {
> @@ -539,6 +579,64 @@ static int opp_parse_supplies(struct dev_pm_opp *opp, struct device *dev,
> return ret;
> }
>
> +static int opp_parse_icc_bw(struct dev_pm_opp *opp, struct device *dev,
> + struct opp_table *opp_table)
> +{
> + struct property *prop = NULL;
> + u32 *bandwidth;
> + char name[] = "bandwidth-MBps";
> + int count, i, j, ret;
> +
> + /* Search for "bandwidth-MBps" */
> + prop = of_find_property(opp->np, name, NULL);
> +
> + /* Missing property is not a problem */
> + if (!prop) {
> + dev_dbg(dev, "%s: Missing %s property\n", __func__, name);
> + return 0;
> + }
> +
> + if (!prop->value) {
> + dev_dbg(dev, "%s: Missing %s value\n", __func__, name);
> + return -ENODATA;
> + }
> +
> + /*
> + * Bandwidth consists of average and peak values like:
> + * bandwidth-MBps = <avg-MBps peak-MBps>
> + */
> + count = prop->length / sizeof(u32);
> + if (count % 2) {
> + dev_err(dev, "%s: Invalid %s values\n", __func__, name);
> + return -EINVAL;
> + }
> +
> + if (opp_table->path_count != count / 2) {
> + dev_err(dev, "%s Mismatch between values and paths (%d %d)\n",
> + __func__, opp_table->path_count, count / 2);
> + return -EINVAL;
> + }
> +
> + bandwidth = kmalloc_array(count, sizeof(*bandwidth), GFP_KERNEL);
> + if (!bandwidth)
> + return -ENOMEM;
> +
> + ret = of_property_read_u32_array(opp->np, name, bandwidth, count);
> + if (ret) {
> + dev_err(dev, "%s: Error parsing %s: %d\n", __func__, name, ret);
> + goto free_bandwidth;
> + }
> + for (i = 0, j = 0; i < count; i++) {
> + opp->bandwidth[i].avg = MBps_to_icc(bandwidth[j++]);
> + opp->bandwidth[i].peak = MBps_to_icc(bandwidth[j++]);
> + }
> +
> +free_bandwidth:
> + kfree(bandwidth);
> +
> + return ret;
> +}
> +
> /**
> * dev_pm_opp_of_remove_table() - Free OPP table entries created from static DT
> * entries
> @@ -635,6 +733,10 @@ static struct dev_pm_opp *_opp_add_static_v2(struct opp_table *opp_table,
> if (opp_table->is_genpd)
> new_opp->pstate = pm_genpd_opp_to_performance_state(dev, new_opp);
>
> + ret = opp_parse_icc_bw(new_opp, dev, opp_table);
> + if (ret)
> + goto free_opp;
> +
> ret = _opp_add(dev, new_opp, opp_table, rate_not_available);
> if (ret) {
> /* Don't return error for duplicate OPPs */
> diff --git a/drivers/opp/opp.h b/drivers/opp/opp.h
> index 569b3525aa67..70a537f2dbd3 100644
> --- a/drivers/opp/opp.h
> +++ b/drivers/opp/opp.h
> @@ -24,6 +24,7 @@
>
> struct clk;
> struct regulator;
> +struct icc_path;
>
> /* Lock to allow exclusive modification to the device and opp lists */
> extern struct mutex opp_table_lock;
> @@ -62,6 +63,7 @@ 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.
> @@ -84,6 +86,7 @@ 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;
>
> @@ -150,6 +153,8 @@ 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
> @@ -194,6 +199,8 @@ 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;
>
> @@ -228,12 +235,14 @@ 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 24c757a32a7b..dabee09a92b8 100644
> --- a/include/linux/pm_opp.h
> +++ b/include/linux/pm_opp.h
> @@ -43,6 +43,18 @@ 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
> @@ -127,6 +139,8 @@ struct opp_table *dev_pm_opp_set_regulators(struct device *dev, const char * con
> void dev_pm_opp_put_regulators(struct opp_table *opp_table);
> struct opp_table *dev_pm_opp_set_clkname(struct device *dev, const char * name);
> void dev_pm_opp_put_clkname(struct opp_table *opp_table);
> +struct opp_table *dev_pm_opp_set_paths(struct device *dev);
> +void dev_pm_opp_put_paths(struct opp_table *opp_table);
> struct opp_table *dev_pm_opp_register_set_opp_helper(struct device *dev, int (*set_opp)(struct dev_pm_set_opp_data *data));
> void dev_pm_opp_unregister_set_opp_helper(struct opp_table *opp_table);
> struct opp_table *dev_pm_opp_set_genpd_virt_dev(struct device *dev, struct device *virt_dev, int index);

--
viresh

Next message: Daniel Drake: "Re: [PATCH 1/2] x86/tsc: use CPUID.0x16 to calculate missing crystal frequency"
Previous message: james qian wang (Arm Technology China): "[PATCH] drm/komeda: Mark the local functions as static"
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