Proceedings of the PM SW Workshop Jun 2010

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(SRF Replacement - OPP Part)
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==SRF Replacement - OPP Part==
==SRF Replacement - OPP Part==
 +
Aligned on using device based OPP approach & maintaining constraints in voltage layer for OPP part of SRF replacement.
 +
===RFC Patches===
===RFC Patches===
Here is a work-in-progress patch that shows work done so far and some of the review comments addressed. Please note that this is in no way completed, compiling, clean patch. It is provided to have a better idea of the changes proposed and discussed.  
Here is a work-in-progress patch that shows work done so far and some of the review comments addressed. Please note that this is in no way completed, compiling, clean patch. It is provided to have a better idea of the changes proposed and discussed.  
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===Minutes & Action Items===
===Minutes & Action Items===
-
* '''VDD MPU, VDD IVA & VDD Core DVFS basic functionality'''  
+
* '''Attaining VDD MPU, VDD IVA & VDD Core DVFS basic functionality'''  
** Shift in approach from voltage domain based OPP to device based OPP
** Shift in approach from voltage domain based OPP to device based OPP
*** OPP will be stored in separate SOC dependent file from other clock, hwmod, voltage files.  
*** OPP will be stored in separate SOC dependent file from other clock, hwmod, voltage files.  
*** These will be loaded into memory and then board-specific modifications will be done.  
*** These will be loaded into memory and then board-specific modifications will be done.  
-
*** The device HWMODs will point to the dynamic versions of the devie-OPPs.
+
*** The device HWMODs will point to the dynamic versions of the device-OPPs.
** Kevin is targeting it for the next merge window – should be doable by month end but needs Thara’s full bandwidth  
** Kevin is targeting it for the next merge window – should be doable by month end but needs Thara’s full bandwidth  
** Kevin will do the data structural changes and get them working with existing SRF – '''Kevin''' by Tuesday 15-Jun
** Kevin will do the data structural changes and get them working with existing SRF – '''Kevin''' by Tuesday 15-Jun
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*** Kevin suggested to use plist (priority assigned doubly linked lists) for this purpose  
*** Kevin suggested to use plist (priority assigned doubly linked lists) for this purpose  
-
 
+
* Enhancement to allow drivers to block or allow rate change of their scalable clocks 
-
* '''APIs to be added to the clock framework'''
+
** The following APIs need to be added to the clock framework to allow drivers to block or allow rate change of their scalable clocks (& their parents)
-
** This will allow drivers to block or allow rate change of their functional or optional clock
+
** The APIs are clock_block_change(), clock_allow_change(), is_clock_rate_change_allowed() – '''Paul''' is OK if some one also picks up this.  
** The APIs are clock_block_change(), clock_allow_change(), is_clock_rate_change_allowed() – '''Paul''' is OK if some one also picks up this.  
** Need to ensure that the implementation doesn’t result into race conditions  
** Need to ensure that the implementation doesn’t result into race conditions  

Revision as of 14:51, 11 June 2010

This wikipage contains proceedings of the PM SW Workshop held in Bangalore on 7-11 Jun, 2010

Contents

HWMOD Framework Enhancements

Reset Management Support in HWMOD

More Granular HWMOD Structures

Multi-level omap_device_idle

Placeholder for patches from Vibhore to support device latency contraint

Access to HWMOD Internal Data

Miscellaneous Issues

Minutes & Action Items


Power Domain And Clock Domain Cleanup

Aligned on the following two phase approach


SRF Replacement - Constraints Part

Types of Latency Constraints

Details of Interrupt Latency

Details of Device Latency

Proposed Implementation

void omap_pm_set_max_dev_wakeup_lat(struct device *dev, long t)
{
	/*  existing code */	
	1. Look for devices’ power domain (might be multiple step if starting  with general device)
	2. Use device name as identifier for constraint request

	if (t == -1)
		pwrdm_release_wakeup_lat_constraint (pwrdm, lat_dev_name);
	else
		 pwrdm_set_wakeup_lat_constraint (pwrdm, lat_dev_name, t);
}
struct powerdomain {
/* existing entries*/
const u32 wakeup_lat[PWRDM_MAX_PWRSTS-1];
static LIST_HEAD(wakeup_lat_constraint_list);
} 
static struct powerdomain core_44xx_pwrdm = {
.wakeup_lat = {
50,   /* off */
20,   /* ret */ -1 for not supported power state
0,     /* inactive */ Do we have to worry about OSWR?
}
}
pwrdm_set_wakeup_lat_constraint (struct powerdomain *pwrdm, char *lat_dev_name, long lat_us){
	1. If new constraint, add a new entry to wakeup_lat_constraint_list
	2. If already existing, update entries’ latency value
	3. pwrdm_check_for_state_change (pwrdm)
} 
pwrdm_release_wakeup_lat_constraint (struct powerdomain *pwrdm, char   *lat_dev_name){
	1. Remove this devices’ constraint from wakeup_lat_constraint_list
	2. pwrdm_check_for_state_change (pwrdm)
}
pwrdm_check_for_state_change (struct powerdomain *pwrdm){
	1. min_latency = find_min_wakeup_latency_constraint (pwrdm) 
		 //go through the list for minimum latency value
	2. find power state that has latency lower than minimum constraint
		 for (new_state = 0x0; new_state < PWRDM_MAX_PWRSTS; new_state++){
		    if (pwrdm->wakeup_lat[i] < min_latency) break;
		}
	3.  if (pwrdm->state != new_state)
 		    pwrdm_set_next_pwrst (pwrdm, new_state); // existing function to program next state
}

Minutes & Action Items

.wakeuplat = {
    [FUNC-PWRST-OFF] = 50,
   [FUNC-PWRST-OSWR] = 30,
  [FUNC-PWRST-CSWR] = 5,
  [FUNC-PWRST-ON] = 0,
};
.func_pwrsts = (FUNC_PWRST_OFF | FUNC_PWRST_OSWR | FUNC_PWRST_CSWR |   FUNC_PWRST_ON)
1 << FUNC_PWRST_OFF
pwrdm_wakelat_set_constraint
pwrdm_wakeuplat_remove_constraint
pwrdm_wakeuplat_update_pwrst)


SRF Replacement - OPP Part

Aligned on using device based OPP approach & maintaining constraints in voltage layer for OPP part of SRF replacement.

RFC Patches

Here is a work-in-progress patch that shows work done so far and some of the review comments addressed. Please note that this is in no way completed, compiling, clean patch. It is provided to have a better idea of the changes proposed and discussed.

File:SRF Replacement OPP Part RFC Patch.pdf

Minutes & Action Items

Review of Device Driver HWMOD Adaptations

MUSB


MMC


DSS


DMA


General Minutes and Action Items

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