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@@ -71,14 +71,14 @@ operations until that OPP could be re-enabled if possible.
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OPP library facilitates this concept in it's implementation. The following
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operational functions operate only on available opps:
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-opp_find_freq_{ceil, floor}, opp_get_voltage, opp_get_freq, opp_get_opp_count
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-and opp_init_cpufreq_table
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+opp_find_freq_{ceil, floor}, dev_pm_opp_get_voltage, dev_pm_opp_get_freq, dev_pm_opp_get_opp_count
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+and dev_pm_opp_init_cpufreq_table
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-opp_find_freq_exact is meant to be used to find the opp pointer which can then
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-be used for opp_enable/disable functions to make an opp available as required.
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+dev_pm_opp_find_freq_exact is meant to be used to find the opp pointer which can then
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+be used for dev_pm_opp_enable/disable functions to make an opp available as required.
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WARNING: Users of OPP library should refresh their availability count using
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-get_opp_count if opp_enable/disable functions are invoked for a device, the
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+get_opp_count if dev_pm_opp_enable/disable functions are invoked for a device, the
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exact mechanism to trigger these or the notification mechanism to other
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dependent subsystems such as cpufreq are left to the discretion of the SoC
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specific framework which uses the OPP library. Similar care needs to be taken
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@@ -96,24 +96,24 @@ using RCU read locks. The opp_find_freq_{exact,ceil,floor},
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opp_get_{voltage, freq, opp_count} fall into this category.
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opp_{add,enable,disable} are updaters which use mutex and implement it's own
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-RCU locking mechanisms. opp_init_cpufreq_table acts as an updater and uses
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+RCU locking mechanisms. dev_pm_opp_init_cpufreq_table acts as an updater and uses
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mutex to implment RCU updater strategy. These functions should *NOT* be called
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under RCU locks and other contexts that prevent blocking functions in RCU or
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mutex operations from working.
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2. Initial OPP List Registration
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================================
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-The SoC implementation calls opp_add function iteratively to add OPPs per
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+The SoC implementation calls dev_pm_opp_add function iteratively to add OPPs per
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device. It is expected that the SoC framework will register the OPP entries
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optimally- typical numbers range to be less than 5. The list generated by
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registering the OPPs is maintained by OPP library throughout the device
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operation. The SoC framework can subsequently control the availability of the
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-OPPs dynamically using the opp_enable / disable functions.
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+OPPs dynamically using the dev_pm_opp_enable / disable functions.
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-opp_add - Add a new OPP for a specific domain represented by the device pointer.
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+dev_pm_opp_add - Add a new OPP for a specific domain represented by the device pointer.
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The OPP is defined using the frequency and voltage. Once added, the OPP
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is assumed to be available and control of it's availability can be done
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- with the opp_enable/disable functions. OPP library internally stores
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+ with the dev_pm_opp_enable/disable functions. OPP library internally stores
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and manages this information in the opp struct. This function may be
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used by SoC framework to define a optimal list as per the demands of
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SoC usage environment.
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@@ -124,7 +124,7 @@ opp_add - Add a new OPP for a specific domain represented by the device pointer.
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soc_pm_init()
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{
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/* Do things */
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- r = opp_add(mpu_dev, 1000000, 900000);
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+ r = dev_pm_opp_add(mpu_dev, 1000000, 900000);
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if (!r) {
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pr_err("%s: unable to register mpu opp(%d)\n", r);
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goto no_cpufreq;
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@@ -143,44 +143,44 @@ functions return the matching pointer representing the opp if a match is
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found, else returns error. These errors are expected to be handled by standard
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error checks such as IS_ERR() and appropriate actions taken by the caller.
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-opp_find_freq_exact - Search for an OPP based on an *exact* frequency and
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+dev_pm_opp_find_freq_exact - Search for an OPP based on an *exact* frequency and
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availability. This function is especially useful to enable an OPP which
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is not available by default.
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Example: In a case when SoC framework detects a situation where a
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higher frequency could be made available, it can use this function to
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- find the OPP prior to call the opp_enable to actually make it available.
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+ find the OPP prior to call the dev_pm_opp_enable to actually make it available.
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rcu_read_lock();
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- opp = opp_find_freq_exact(dev, 1000000000, false);
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+ opp = dev_pm_opp_find_freq_exact(dev, 1000000000, false);
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rcu_read_unlock();
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/* dont operate on the pointer.. just do a sanity check.. */
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if (IS_ERR(opp)) {
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pr_err("frequency not disabled!\n");
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/* trigger appropriate actions.. */
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} else {
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- opp_enable(dev,1000000000);
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+ dev_pm_opp_enable(dev,1000000000);
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}
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NOTE: This is the only search function that operates on OPPs which are
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not available.
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-opp_find_freq_floor - Search for an available OPP which is *at most* the
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+dev_pm_opp_find_freq_floor - Search for an available OPP which is *at most* the
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provided frequency. This function is useful while searching for a lesser
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match OR operating on OPP information in the order of decreasing
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frequency.
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Example: To find the highest opp for a device:
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freq = ULONG_MAX;
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rcu_read_lock();
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- opp_find_freq_floor(dev, &freq);
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+ dev_pm_opp_find_freq_floor(dev, &freq);
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rcu_read_unlock();
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-opp_find_freq_ceil - Search for an available OPP which is *at least* the
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+dev_pm_opp_find_freq_ceil - Search for an available OPP which is *at least* the
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provided frequency. This function is useful while searching for a
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higher match OR operating on OPP information in the order of increasing
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frequency.
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Example 1: To find the lowest opp for a device:
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freq = 0;
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rcu_read_lock();
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- opp_find_freq_ceil(dev, &freq);
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+ dev_pm_opp_find_freq_ceil(dev, &freq);
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rcu_read_unlock();
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Example 2: A simplified implementation of a SoC cpufreq_driver->target:
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soc_cpufreq_target(..)
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@@ -188,7 +188,7 @@ opp_find_freq_ceil - Search for an available OPP which is *at least* the
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/* Do stuff like policy checks etc. */
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/* Find the best frequency match for the req */
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rcu_read_lock();
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- opp = opp_find_freq_ceil(dev, &freq);
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+ opp = dev_pm_opp_find_freq_ceil(dev, &freq);
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rcu_read_unlock();
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if (!IS_ERR(opp))
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soc_switch_to_freq_voltage(freq);
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@@ -208,34 +208,34 @@ as thermal considerations (e.g. don't use OPPx until the temperature drops).
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WARNING: Do not use these functions in interrupt context.
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-opp_enable - Make a OPP available for operation.
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+dev_pm_opp_enable - Make a OPP available for operation.
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Example: Lets say that 1GHz OPP is to be made available only if the
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SoC temperature is lower than a certain threshold. The SoC framework
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implementation might choose to do something as follows:
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if (cur_temp < temp_low_thresh) {
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/* Enable 1GHz if it was disabled */
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rcu_read_lock();
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- opp = opp_find_freq_exact(dev, 1000000000, false);
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+ opp = dev_pm_opp_find_freq_exact(dev, 1000000000, false);
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rcu_read_unlock();
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/* just error check */
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if (!IS_ERR(opp))
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- ret = opp_enable(dev, 1000000000);
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+ ret = dev_pm_opp_enable(dev, 1000000000);
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else
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goto try_something_else;
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}
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-opp_disable - Make an OPP to be not available for operation
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+dev_pm_opp_disable - Make an OPP to be not available for operation
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Example: Lets say that 1GHz OPP is to be disabled if the temperature
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exceeds a threshold value. The SoC framework implementation might
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choose to do something as follows:
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if (cur_temp > temp_high_thresh) {
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/* Disable 1GHz if it was enabled */
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rcu_read_lock();
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- opp = opp_find_freq_exact(dev, 1000000000, true);
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+ opp = dev_pm_opp_find_freq_exact(dev, 1000000000, true);
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rcu_read_unlock();
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/* just error check */
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if (!IS_ERR(opp))
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- ret = opp_disable(dev, 1000000000);
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+ ret = dev_pm_opp_disable(dev, 1000000000);
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else
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goto try_something_else;
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}
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@@ -247,7 +247,7 @@ information from the OPP structure is necessary. Once an OPP pointer is
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retrieved using the search functions, the following functions can be used by SoC
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framework to retrieve the information represented inside the OPP layer.
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-opp_get_voltage - Retrieve the voltage represented by the opp pointer.
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+dev_pm_opp_get_voltage - Retrieve the voltage represented by the opp pointer.
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Example: At a cpufreq transition to a different frequency, SoC
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framework requires to set the voltage represented by the OPP using
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the regulator framework to the Power Management chip providing the
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@@ -256,15 +256,15 @@ opp_get_voltage - Retrieve the voltage represented by the opp pointer.
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{
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/* do things */
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rcu_read_lock();
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- opp = opp_find_freq_ceil(dev, &freq);
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- v = opp_get_voltage(opp);
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+ opp = dev_pm_opp_find_freq_ceil(dev, &freq);
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+ v = dev_pm_opp_get_voltage(opp);
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rcu_read_unlock();
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if (v)
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regulator_set_voltage(.., v);
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/* do other things */
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}
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-opp_get_freq - Retrieve the freq represented by the opp pointer.
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+dev_pm_opp_get_freq - Retrieve the freq represented by the opp pointer.
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Example: Lets say the SoC framework uses a couple of helper functions
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we could pass opp pointers instead of doing additional parameters to
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handle quiet a bit of data parameters.
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@@ -273,8 +273,8 @@ opp_get_freq - Retrieve the freq represented by the opp pointer.
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/* do things.. */
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max_freq = ULONG_MAX;
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rcu_read_lock();
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- max_opp = opp_find_freq_floor(dev,&max_freq);
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- requested_opp = opp_find_freq_ceil(dev,&freq);
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+ max_opp = dev_pm_opp_find_freq_floor(dev,&max_freq);
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+ requested_opp = dev_pm_opp_find_freq_ceil(dev,&freq);
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if (!IS_ERR(max_opp) && !IS_ERR(requested_opp))
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r = soc_test_validity(max_opp, requested_opp);
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rcu_read_unlock();
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@@ -282,25 +282,25 @@ opp_get_freq - Retrieve the freq represented by the opp pointer.
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}
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soc_test_validity(..)
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{
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- if(opp_get_voltage(max_opp) < opp_get_voltage(requested_opp))
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+ if(dev_pm_opp_get_voltage(max_opp) < dev_pm_opp_get_voltage(requested_opp))
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return -EINVAL;
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- if(opp_get_freq(max_opp) < opp_get_freq(requested_opp))
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+ if(dev_pm_opp_get_freq(max_opp) < dev_pm_opp_get_freq(requested_opp))
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return -EINVAL;
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/* do things.. */
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}
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-opp_get_opp_count - Retrieve the number of available opps for a device
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+dev_pm_opp_get_opp_count - Retrieve the number of available opps for a device
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Example: Lets say a co-processor in the SoC needs to know the available
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frequencies in a table, the main processor can notify as following:
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soc_notify_coproc_available_frequencies()
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{
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/* Do things */
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rcu_read_lock();
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- num_available = opp_get_opp_count(dev);
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+ num_available = dev_pm_opp_get_opp_count(dev);
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speeds = kzalloc(sizeof(u32) * num_available, GFP_KERNEL);
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/* populate the table in increasing order */
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freq = 0;
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- while (!IS_ERR(opp = opp_find_freq_ceil(dev, &freq))) {
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+ while (!IS_ERR(opp = dev_pm_opp_find_freq_ceil(dev, &freq))) {
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speeds[i] = freq;
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freq++;
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i++;
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@@ -313,7 +313,7 @@ opp_get_opp_count - Retrieve the number of available opps for a device
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6. Cpufreq Table Generation
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===========================
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-opp_init_cpufreq_table - cpufreq framework typically is initialized with
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+dev_pm_opp_init_cpufreq_table - cpufreq framework typically is initialized with
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cpufreq_frequency_table_cpuinfo which is provided with the list of
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frequencies that are available for operation. This function provides
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a ready to use conversion routine to translate the OPP layer's internal
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@@ -326,7 +326,7 @@ opp_init_cpufreq_table - cpufreq framework typically is initialized with
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soc_pm_init()
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{
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/* Do things */
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- r = opp_init_cpufreq_table(dev, &freq_table);
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+ r = dev_pm_opp_init_cpufreq_table(dev, &freq_table);
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if (!r)
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cpufreq_frequency_table_cpuinfo(policy, freq_table);
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/* Do other things */
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@@ -336,7 +336,7 @@ opp_init_cpufreq_table - cpufreq framework typically is initialized with
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addition to CONFIG_PM as power management feature is required to
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dynamically scale voltage and frequency in a system.
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-opp_free_cpufreq_table - Free up the table allocated by opp_init_cpufreq_table
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+dev_pm_opp_free_cpufreq_table - Free up the table allocated by dev_pm_opp_init_cpufreq_table
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7. Data Structures
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==================
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@@ -366,8 +366,8 @@ struct opp - The internal data structure of OPP library which is used to
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identifier for OPP in the interactions with OPP layer.
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WARNING: The struct opp pointer should not be parsed or modified by the
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- users. The defaults of for an instance is populated by opp_add, but the
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- availability of the OPP can be modified by opp_enable/disable functions.
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+ users. The defaults of for an instance is populated by dev_pm_opp_add, but the
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+ availability of the OPP can be modified by dev_pm_opp_enable/disable functions.
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struct device - This is used to identify a domain to the OPP layer. The
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nature of the device and it's implementation is left to the user of
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@@ -377,19 +377,19 @@ Overall, in a simplistic view, the data structure operations is represented as
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following:
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Initialization / modification:
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- +-----+ /- opp_enable
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-opp_add --> | opp | <-------
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- | +-----+ \- opp_disable
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+ +-----+ /- dev_pm_opp_enable
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+dev_pm_opp_add --> | opp | <-------
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+ | +-----+ \- dev_pm_opp_disable
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\-------> domain_info(device)
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Search functions:
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- /-- opp_find_freq_ceil ---\ +-----+
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-domain_info<---- opp_find_freq_exact -----> | opp |
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- \-- opp_find_freq_floor ---/ +-----+
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+ /-- dev_pm_opp_find_freq_ceil ---\ +-----+
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+domain_info<---- dev_pm_opp_find_freq_exact -----> | opp |
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+ \-- dev_pm_opp_find_freq_floor ---/ +-----+
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Retrieval functions:
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-+-----+ /- opp_get_voltage
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++-----+ /- dev_pm_opp_get_voltage
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| opp | <---
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-+-----+ \- opp_get_freq
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++-----+ \- dev_pm_opp_get_freq
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-domain_info <- opp_get_opp_count
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+domain_info <- dev_pm_opp_get_opp_count
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Nishanth Menon