[05/10] opp: Add support to parse "operating-points-v2" bindings

Message ID 1b5a393f2162752cbb773956dff15739e7525a1d.1434369079.git.viresh.kumar@linaro.org
State New
Headers show

Commit Message

Viresh Kumar June 15, 2015, 11:57 a.m.
This adds support in OPP library to parse and create list of OPPs from
operating-points-v2 bindings. It takes care of most of the properties of
new bindings (except shared-opp, which will be handled separately).

For backward compatibility, we keep supporting earlier bindings. We try
to search for the new bindings first, in case they aren't present we
look for the old deprecated ones.

There are few things marked as TODO:
- Support for multiple OPP tables
- Support for multiple regulators

They should be fixed separately.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
---
 drivers/base/power/opp.c | 238 ++++++++++++++++++++++++++++++++++++++++++-----
 1 file changed, 213 insertions(+), 25 deletions(-)

Comments

Viresh Kumar July 2, 2015, 6:38 a.m. | #1
On 01-07-15, 18:13, Stephen Boyd wrote:
> On 06/15/2015 04:57 AM, Viresh Kumar wrote:
> > ---
> >  drivers/base/power/opp.c | 238 ++++++++++++++++++++++++++++++++++++++++++-----
> >  1 file changed, 213 insertions(+), 25 deletions(-)
> >
> > diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
> > index 2ac48ff9c1ef..3198c3e77224 100644
> > --- a/drivers/base/power/opp.c
> > +++ b/drivers/base/power/opp.c
> > @@ -49,12 +49,17 @@
> >   *		are protected by the dev_opp_list_lock for integrity.
> >   *		IMPORTANT: the opp nodes should be maintained in increasing
> >   *		order.
> > - * @dynamic:	not-created from static DT entries.
> >   * @available:	true/false - marks if this OPP as available or not
> > + * @dynamic:	not-created from static DT entries.
> 
> Why move dynamic?

To match its position, as it is present in the struct below. Yes it
could have been done in a separate patch, but its also fine to fix
such silly mistakes in another patch :)

> > + * @turbo:	true if turbo (boost) OPP
> >   * @rate:	Frequency in hertz
> > - * @u_volt:	Nominal voltage in microvolts corresponding to this OPP
> > + * @u_volt:	Target voltage in microvolts corresponding to this OPP
> > + * @u_volt_min:	Minimum voltage in microvolts corresponding to this OPP
> > + * @u_volt_max:	Maximum voltage in microvolts corresponding to this OPP
> > + * @u_amp:	Maximum current drawn by the device in microamperes
> >   * @dev_opp:	points back to the device_opp struct this opp belongs to
> >   * @rcu_head:	RCU callback head used for deferred freeing
> > + * @np:		OPP's device node.
> >   *
> >   * This structure stores the OPP information for a given device.
> >   */
> > @@ -63,11 +68,22 @@ struct dev_pm_opp {
> >  
> >  	bool available;
> >  	bool dynamic;
> > +	bool turbo;
> >  	unsigned long rate;
> > +
> > +	/*
> > +	 * Order in which u_volt{_min|_max} are present in this structure
> > +	 * shouldn't be changed.
> > +	 */
> >  	unsigned long u_volt;
> > +	unsigned long u_volt_min;
> > +	unsigned long u_volt_max;
> > +	unsigned long u_amp;
> >  
> >  	struct device_opp *dev_opp;
> >  	struct rcu_head rcu_head;
> > +
> > +	struct device_node *np;
> >  };
> >  
> >  /**
> > @@ -501,6 +517,7 @@ static void _opp_remove(struct device_opp *dev_opp,
> >  	 */
> >  	if (notify)
> >  		srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp);
> > +
> >  	list_del_rcu(&opp->node);
> >  	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
> >  
> 
> Please remove this hunk of noise.

Sigh

> > @@ -675,6 +692,100 @@ static int _opp_add_dynamic(struct device *dev, unsigned long freq,
> >  }
> >  
> >  /**
> > + * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
> > + * @dev:	device for which we do this operation
> > + * @np:		device node
> > + *
> > + * This function adds an opp definition to the opp list and returns status. The
> > + * opp can be controlled using dev_pm_opp_enable/disable functions and may be
> > + * removed by dev_pm_opp_remove.
> > + *
> > + * Locking: The internal device_opp and opp structures are RCU protected.
> > + * Hence this function internally uses RCU updater strategy with mutex locks
> > + * to keep the integrity of the internal data structures. Callers should ensure
> > + * that this function is *NOT* called under RCU protection or in contexts where
> > + * mutex cannot be locked.
> > + *
> > + * Return:
> > + * 0		On success OR
> > + *		Duplicate OPPs (both freq and volt are same) and opp->available
> > + * -EEXIST	Freq are same and volt are different OR
> > + *		Duplicate OPPs (both freq and volt are same) and !opp->available
> > + * -ENOMEM	Memory allocation failure
> > + * -EINVAL	Failed parsing the OPP node
> > + */
> > +static int _opp_add_static_v2(struct device *dev, struct device_node *np)
> > +{
> > +	struct device_opp *dev_opp;
> > +	struct dev_pm_opp *new_opp;
> > +	int ret;
> > +
> > +	/* Hold our list modification lock here */
> > +	mutex_lock(&dev_opp_list_lock);
> > +
> > +	new_opp = _allocate_opp(dev, &dev_opp);
> > +	if (!new_opp) {
> > +		ret = -ENOMEM;
> > +		goto unlock;
> > +	}
> > +
> > +	ret = of_property_read_u32(np, "opp-hz", (u32 *)&new_opp->rate);
> > +	if (ret < 0) {
> > +		dev_err(dev, "%s: opp-hz not found\n", __func__);
> > +		goto free_opp;
> > +	}
> > +
> > +	if (of_get_property(np, "turbo-mode", NULL))
> > +		new_opp->turbo = true;
> 
> new_opp->turbo = of_property_read_bool(np, "turbo-mode");

Sure.

> > +
> > +	new_opp->np = np;
> > +	new_opp->dynamic = false;
> > +	new_opp->available = true;
> > +
> > +	/*
> > +	 * TODO: Support multiple regulators
> > +	 *
> > +	 * read opp-microvolt array
> > +	 */
> > +	ret = of_property_count_u32_elems(np, "opp-microvolt");
> > +	if (ret == 1 || ret == 3) {
> > +		/* There can be one or three elements here */
> > +		ret = of_property_read_u32_array(np, "opp-microvolt",
> > +						 (u32 *)&new_opp->u_volt, ret);
> 
> It seems fragile to rely on the struct packing here. Maybe the same
> comment in the struct should be copied here, and possibly some better
> way of doing this so the code can't be subtly broken?

Any example of how things will break? Aren't these guaranteed to be
present at 3 consecutive 32 bit positions ?

> > +
> > +	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu\n",
> > +		 __func__, new_opp->turbo, new_opp->rate, new_opp->u_volt,
> > +		 new_opp->u_volt_min, new_opp->u_volt_max);
> > +
> > +	mutex_unlock(&dev_opp_list_lock);
> 
> We can pr_debug after the unlock?

Okay
Viresh Kumar July 9, 2015, 5:18 a.m. | #2
On 08-07-15, 15:41, Bartlomiej Zolnierkiewicz wrote:
> Isn't using u32 for storing frequency (in Hz) too small by today's
> standards?
> 
> [ Please note that the old v1 binding uses kHz not Hz. ]

Hmm, probably yes we need it to be u64. Thanks for pointing out.
Viresh Kumar July 27, 2015, 3:02 a.m. | #3
On 08-07-15, 15:41, Bartlomiej Zolnierkiewicz wrote:
> Isn't using u32 for storing frequency (in Hz) too small by today's
> standards?
> 
> [ Please note that the old v1 binding uses kHz not Hz. ]

I have thought about this a bit more and I am somewhat confused. Yes I
agree that u32 isn't big enough for frequencies in Hz, i.e. Max value
of 4294967295 ~ 4.29 GHz.

But the bigger problem lies with the clk API that we have today. It
declares clk-rate as a unsigned-long which is 32 bits on a 32 bit
machine and 64 bits on a 64 bit machine. And every single piece of
code reading "clock-frequency" DT property, reads it as a 32 bit value
as we reserve only a single cell for it.

Now, if we wanna change that, we need to start changing from the
clk-API itself and that's not gonna be a small task and I would leave
it to Mike/Stephen for obvious reasons :)

So, I will keep this code in sync with rest of the kernel and lets see
what Mike has to say.
Viresh Kumar July 29, 2015, 6:53 a.m. | #4
On 28-07-15, 16:03, Stephen Boyd wrote:
> There is talk about moving to 64 bits for the frequency in the clk API.
> It's not actively being developed though and I'm not sure when we'll get
> there. From a DT perspective though, I don't see why it would be bad to
> have two cells instead of one cell for the frequency here. It would
> allow up to 64 bits of frequency so that when we change the clk API we
> won't need to do anything in the OPP bindings to handle it. Just because
> we have problems in the kernel doesn't mean we should put the same
> problems into DT.

Okay, I am going to send a patch for that as well and will respin the
series again.

Patch

diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index 2ac48ff9c1ef..3198c3e77224 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -49,12 +49,17 @@ 
  *		are protected by the dev_opp_list_lock for integrity.
  *		IMPORTANT: the opp nodes should be maintained in increasing
  *		order.
- * @dynamic:	not-created from static DT entries.
  * @available:	true/false - marks if this OPP as available or not
+ * @dynamic:	not-created from static DT entries.
+ * @turbo:	true if turbo (boost) OPP
  * @rate:	Frequency in hertz
- * @u_volt:	Nominal voltage in microvolts corresponding to this OPP
+ * @u_volt:	Target voltage in microvolts corresponding to this OPP
+ * @u_volt_min:	Minimum voltage in microvolts corresponding to this OPP
+ * @u_volt_max:	Maximum voltage in microvolts corresponding to this OPP
+ * @u_amp:	Maximum current drawn by the device in microamperes
  * @dev_opp:	points back to the device_opp struct this opp belongs to
  * @rcu_head:	RCU callback head used for deferred freeing
+ * @np:		OPP's device node.
  *
  * This structure stores the OPP information for a given device.
  */
@@ -63,11 +68,22 @@  struct dev_pm_opp {
 
 	bool available;
 	bool dynamic;
+	bool turbo;
 	unsigned long rate;
+
+	/*
+	 * Order in which u_volt{_min|_max} are present in this structure
+	 * shouldn't be changed.
+	 */
 	unsigned long u_volt;
+	unsigned long u_volt_min;
+	unsigned long u_volt_max;
+	unsigned long u_amp;
 
 	struct device_opp *dev_opp;
 	struct rcu_head rcu_head;
+
+	struct device_node *np;
 };
 
 /**
@@ -501,6 +517,7 @@  static void _opp_remove(struct device_opp *dev_opp,
 	 */
 	if (notify)
 		srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_REMOVE, opp);
+
 	list_del_rcu(&opp->node);
 	call_srcu(&dev_opp->srcu_head.srcu, &opp->rcu_head, _kfree_opp_rcu);
 
@@ -675,6 +692,100 @@  static int _opp_add_dynamic(struct device *dev, unsigned long freq,
 }
 
 /**
+ * _opp_add_static_v2() - Allocate static OPPs (As per 'v2' DT bindings)
+ * @dev:	device for which we do this operation
+ * @np:		device node
+ *
+ * This function adds an opp definition to the opp list and returns status. The
+ * opp can be controlled using dev_pm_opp_enable/disable functions and may be
+ * removed by dev_pm_opp_remove.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function internally uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ *
+ * Return:
+ * 0		On success OR
+ *		Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST	Freq are same and volt are different OR
+ *		Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM	Memory allocation failure
+ * -EINVAL	Failed parsing the OPP node
+ */
+static int _opp_add_static_v2(struct device *dev, struct device_node *np)
+{
+	struct device_opp *dev_opp;
+	struct dev_pm_opp *new_opp;
+	int ret;
+
+	/* Hold our list modification lock here */
+	mutex_lock(&dev_opp_list_lock);
+
+	new_opp = _allocate_opp(dev, &dev_opp);
+	if (!new_opp) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	ret = of_property_read_u32(np, "opp-hz", (u32 *)&new_opp->rate);
+	if (ret < 0) {
+		dev_err(dev, "%s: opp-hz not found\n", __func__);
+		goto free_opp;
+	}
+
+	if (of_get_property(np, "turbo-mode", NULL))
+		new_opp->turbo = true;
+
+	new_opp->np = np;
+	new_opp->dynamic = false;
+	new_opp->available = true;
+
+	/*
+	 * TODO: Support multiple regulators
+	 *
+	 * read opp-microvolt array
+	 */
+	ret = of_property_count_u32_elems(np, "opp-microvolt");
+	if (ret == 1 || ret == 3) {
+		/* There can be one or three elements here */
+		ret = of_property_read_u32_array(np, "opp-microvolt",
+						 (u32 *)&new_opp->u_volt, ret);
+		if (ret) {
+			dev_err(dev, "%s: error parsing opp-microvolt: %d\n",
+				__func__, ret);
+			goto free_opp;
+		}
+	}
+
+	of_property_read_u32(np, "opp-microamp", (u32 *)&new_opp->u_amp);
+
+	ret = _opp_add(new_opp, dev_opp);
+	if (ret)
+		goto free_opp;
+
+	pr_debug("%s: turbo:%d rate:%lu uv:%lu uvmin:%lu uvmax:%lu\n",
+		 __func__, new_opp->turbo, new_opp->rate, new_opp->u_volt,
+		 new_opp->u_volt_min, new_opp->u_volt_max);
+
+	mutex_unlock(&dev_opp_list_lock);
+
+	/*
+	 * Notify the changes in the availability of the operable
+	 * frequency/voltage list.
+	 */
+	srcu_notifier_call_chain(&dev_opp->srcu_head, OPP_EVENT_ADD, new_opp);
+	return 0;
+
+free_opp:
+	_opp_remove(dev_opp, new_opp, false);
+unlock:
+	mutex_unlock(&dev_opp_list_lock);
+	return ret;
+}
+
+/**
  * dev_pm_opp_add()  - Add an OPP table from a table definitions
  * @dev:	device for which we do this operation
  * @freq:	Frequency in Hz for this OPP
@@ -905,29 +1016,64 @@  void of_free_opp_table(struct device *dev)
 }
 EXPORT_SYMBOL_GPL(of_free_opp_table);
 
-/**
- * of_init_opp_table() - Initialize opp table from device tree
- * @dev:	device pointer used to lookup device OPPs.
- *
- * Register the initial OPP table with the OPP library for given device.
- *
- * Locking: The internal device_opp and opp structures are RCU protected.
- * Hence this function indirectly uses RCU updater strategy with mutex locks
- * to keep the integrity of the internal data structures. Callers should ensure
- * that this function is *NOT* called under RCU protection or in contexts where
- * mutex cannot be locked.
- *
- * Return:
- * 0		On success OR
- *		Duplicate OPPs (both freq and volt are same) and opp->available
- * -EEXIST	Freq are same and volt are different OR
- *		Duplicate OPPs (both freq and volt are same) and !opp->available
- * -ENOMEM	Memory allocation failure
- * -ENODEV	when 'operating-points' property is not found or is invalid data
- *		in device node.
- * -ENODATA	when empty 'operating-points' property is found
- */
-int of_init_opp_table(struct device *dev)
+/* Returns opp descriptor node from its phandle. Caller must do of_node_put() */
+static struct device_node *
+_of_get_opp_desc_node_from_prop(struct device *dev, const struct property *prop)
+{
+	struct device_node *opp_np;
+
+	opp_np = of_find_node_by_phandle(be32_to_cpup(prop->value));
+	if (!opp_np) {
+		dev_err(dev, "%s: Prop: %s contains invalid opp desc phandle\n",
+			__func__, prop->name);
+		return ERR_PTR(-EINVAL);
+	}
+
+	return opp_np;
+}
+
+/* Initializes OPP tables based on new bindings */
+static int _of_init_opp_table_v2(struct device *dev,
+				 const struct property *prop)
+{
+	struct device_node *opp_np, *np;
+	int ret = 0, count = 0;
+
+	if (!prop->value)
+		return -ENODATA;
+
+	/* Get opp node */
+	opp_np = _of_get_opp_desc_node_from_prop(dev, prop);
+	if (IS_ERR(opp_np))
+		return PTR_ERR(opp_np);
+
+	/* We have opp-list node now, iterate over it and add OPPs */
+	for_each_available_child_of_node(opp_np, np) {
+		count++;
+
+		ret = _opp_add_static_v2(dev, np);
+		if (ret) {
+			dev_err(dev, "%s: Failed to add OPP, %d\n", __func__,
+				ret);
+			break;
+		}
+	}
+
+	/* There should be one of more OPP defined */
+	if (WARN_ON(!count))
+		goto put_opp_np;
+
+	if (ret)
+		of_free_opp_table(dev);
+
+put_opp_np:
+	of_node_put(opp_np);
+
+	return ret;
+}
+
+/* Initializes OPP tables based on old-deprecated bindings */
+static int _of_init_opp_table_v1(struct device *dev)
 {
 	const struct property *prop;
 	const __be32 *val;
@@ -962,5 +1108,47 @@  int of_init_opp_table(struct device *dev)
 
 	return 0;
 }
+
+/**
+ * of_init_opp_table() - Initialize opp table from device tree
+ * @dev:	device pointer used to lookup device OPPs.
+ *
+ * Register the initial OPP table with the OPP library for given device.
+ *
+ * Locking: The internal device_opp and opp structures are RCU protected.
+ * Hence this function indirectly uses RCU updater strategy with mutex locks
+ * to keep the integrity of the internal data structures. Callers should ensure
+ * that this function is *NOT* called under RCU protection or in contexts where
+ * mutex cannot be locked.
+ *
+ * Return:
+ * 0		On success OR
+ *		Duplicate OPPs (both freq and volt are same) and opp->available
+ * -EEXIST	Freq are same and volt are different OR
+ *		Duplicate OPPs (both freq and volt are same) and !opp->available
+ * -ENOMEM	Memory allocation failure
+ * -ENODEV	when 'operating-points' property is not found or is invalid data
+ *		in device node.
+ * -ENODATA	when empty 'operating-points' property is found
+ */
+int of_init_opp_table(struct device *dev)
+{
+	const struct property *prop;
+
+	/*
+	 * OPPs have two version of bindings now. The older one is deprecated,
+	 * try for the new binding first.
+	 */
+	prop = of_find_property(dev->of_node, "operating-points-v2", NULL);
+	if (!prop) {
+		/*
+		 * Try old-deprecated bindings for backward compatibility with
+		 * older dtbs.
+		 */
+		return _of_init_opp_table_v1(dev);
+	}
+
+	return _of_init_opp_table_v2(dev, prop);
+}
 EXPORT_SYMBOL_GPL(of_init_opp_table);
 #endif