Commit c0407a96 authored by Paul Walmsley's avatar Paul Walmsley Committed by paul

OMAP2/3 PM: create the OMAP PM interface and add a default OMAP PM no-op layer

The interface provides device drivers, CPUFreq, and DSPBridge with a
means of controlling OMAP power management parameters that are not yet
supported by the Linux PM PMQoS interface.  Copious documentation is
in the patch in Documentation/arm/OMAP/omap_pm and the interface
header file, arch/arm/plat-omap/include/mach/omap-pm.h.

Thanks to Rajendra Nayak <rnayak@ti.com> for adding CORE (VDD2) OPP
support and moving the OPP table initialization earlier in the event
that the clock code needs them.  Thanks to Tero Kristo
<tero.kristo@nokia.com> for fixing the parameter check in
omap_pm_set_min_bus_tput().  Jouni signed off on Tero's patch.
Signed-off-by: default avatarPaul Walmsley <paul@pwsan.com>
Signed-off-by: default avatarKevin Hilman <khilman@deeprootsystems.com>
Signed-off-by: default avatarRajendra Nayak <rnayak@ti.com>
Signed-off-by: default avatarTero Kristo <tero.kristo@nokia.com>
Signed-off-by: default avatarJouni Högander <jouni.hogander@nokia.com>
Cc: Tony Lindgren <tony@atomide.com>
Cc: Igor Stoppa <igor.stoppa@nokia.com>
Cc: Richard Woodruff <r-woodruff2@ti.com>
Cc: Anand Sawant <sawant@ti.com>
Cc: Sakari Poussa <sakari.poussa@nokia.com>
Cc: Veeramanikandan Raju <veera@ti.com>
Cc: Karthik Dasu <karthik-dp@ti.com>
parent 08e3d5f2
The OMAP PM interface
=====================
This document describes the temporary OMAP PM interface. Driver
authors use these functions to communicate minimum latency or
throughput constraints to the kernel power management code.
Over time, the intention is to merge features from the OMAP PM
interface into the Linux PM QoS code.
Drivers need to express PM parameters which:
- support the range of power management parameters present in the TI SRF;
- separate the drivers from the underlying PM parameter
implementation, whether it is the TI SRF or Linux PM QoS or Linux
latency framework or something else;
- specify PM parameters in terms of fundamental units, such as
latency and throughput, rather than units which are specific to OMAP
or to particular OMAP variants;
- allow drivers which are shared with other architectures (e.g.,
DaVinci) to add these constraints in a way which won't affect non-OMAP
systems,
- can be implemented immediately with minimal disruption of other
architectures.
This document proposes the OMAP PM interface, including the following
five power management functions for driver code:
1. Set the maximum MPU wakeup latency:
(*pdata->set_max_mpu_wakeup_lat)(struct device *dev, unsigned long t)
2. Set the maximum device wakeup latency:
(*pdata->set_max_dev_wakeup_lat)(struct device *dev, unsigned long t)
3. Set the maximum system DMA transfer start latency (CORE pwrdm):
(*pdata->set_max_sdma_lat)(struct device *dev, long t)
4. Set the minimum bus throughput needed by a device:
(*pdata->set_min_bus_tput)(struct device *dev, u8 agent_id, unsigned long r)
5. Return the number of times the device has lost context
(*pdata->get_dev_context_loss_count)(struct device *dev)
Further documentation for all OMAP PM interface functions can be
found in arch/arm/plat-omap/include/mach/omap-pm.h.
The OMAP PM layer is intended to be temporary
---------------------------------------------
The intention is that eventually the Linux PM QoS layer should support
the range of power management features present in OMAP3. As this
happens, existing drivers using the OMAP PM interface can be modified
to use the Linux PM QoS code; and the OMAP PM interface can disappear.
Driver usage of the OMAP PM functions
-------------------------------------
As the 'pdata' in the above examples indicates, these functions are
exposed to drivers through function pointers in driver .platform_data
structures. The function pointers are initialized by the board-*.c
files to point to the corresponding OMAP PM functions:
.set_max_dev_wakeup_lat will point to
omap_pm_set_max_dev_wakeup_lat(), etc. Other architectures which do
not support these functions should leave these function pointers set
to NULL. Drivers should use the following idiom:
if (pdata->set_max_dev_wakeup_lat)
(*pdata->set_max_dev_wakeup_lat)(dev, t);
The most common usage of these functions will probably be to specify
the maximum time from when an interrupt occurs, to when the device
becomes accessible. To accomplish this, driver writers should use the
set_max_mpu_wakeup_lat() function to to constrain the MPU wakeup
latency, and the set_max_dev_wakeup_lat() function to constrain the
device wakeup latency (from clk_enable() to accessibility). For
example,
/* Limit MPU wakeup latency */
if (pdata->set_max_mpu_wakeup_lat)
(*pdata->set_max_mpu_wakeup_lat)(dev, tc);
/* Limit device powerdomain wakeup latency */
if (pdata->set_max_dev_wakeup_lat)
(*pdata->set_max_dev_wakeup_lat)(dev, td);
/* total wakeup latency in this example: (tc + td) */
The PM parameters can be overwritten by calling the function again
with the new value. The settings can be removed by calling the
function with a t argument of -1 (except in the case of
set_max_bus_tput(), which should be called with an r argument of 0).
The fifth function above, omap_pm_get_dev_context_loss_count(),
is intended as an optimization to allow drivers to determine whether the
device has lost its internal context. If context has been lost, the
driver must restore its internal context before proceeding.
Other specialized interface functions
-------------------------------------
The five functions listed above are intended to be usable by any
device driver. DSPBridge and CPUFreq have a few special requirements.
DSPBridge expresses target DSP performance levels in terms of OPP IDs.
CPUFreq expresses target MPU performance levels in terms of MPU
frequency. The OMAP PM interface contains functions for these
specialized cases to convert that input information (OPPs/MPU
frequency) into the form that the underlying power management
implementation needs:
6. (*pdata->dsp_get_opp_table)(void)
7. (*pdata->dsp_set_min_opp)(u8 opp_id)
8. (*pdata->dsp_get_opp)(void)
9. (*pdata->cpu_get_freq_table)(void)
10. (*pdata->cpu_set_freq)(unsigned long f)
11. (*pdata->cpu_get_freq)(void)
...@@ -36,6 +36,7 @@ ...@@ -36,6 +36,7 @@
#ifndef CONFIG_ARCH_OMAP4 /* FIXME: Remove this once clkdev is ready */ #ifndef CONFIG_ARCH_OMAP4 /* FIXME: Remove this once clkdev is ready */
#include "clock.h" #include "clock.h"
#include <mach/omap-pm.h>
#include <mach/powerdomain.h> #include <mach/powerdomain.h>
#include "powerdomains.h" #include "powerdomains.h"
...@@ -281,9 +282,12 @@ void __init omap2_init_common_hw(struct omap_sdrc_params *sdrc_cs0, ...@@ -281,9 +282,12 @@ void __init omap2_init_common_hw(struct omap_sdrc_params *sdrc_cs0,
{ {
omap2_mux_init(); omap2_mux_init();
#ifndef CONFIG_ARCH_OMAP4 /* FIXME: Remove this once the clkdev is ready */ #ifndef CONFIG_ARCH_OMAP4 /* FIXME: Remove this once the clkdev is ready */
/* The OPP tables have to be registered before a clk init */
omap_pm_if_early_init(mpu_opps, dsp_opps, l3_opps);
pwrdm_init(powerdomains_omap); pwrdm_init(powerdomains_omap);
clkdm_init(clockdomains_omap, clkdm_pwrdm_autodeps); clkdm_init(clockdomains_omap, clkdm_pwrdm_autodeps);
omap2_clk_init(); omap2_clk_init();
omap_pm_if_init();
omap2_sdrc_init(sdrc_cs0, sdrc_cs1); omap2_sdrc_init(sdrc_cs0, sdrc_cs1);
_omap2_init_reprogram_sdrc(); _omap2_init_reprogram_sdrc();
#endif #endif
......
...@@ -187,6 +187,19 @@ config OMAP_SERIAL_WAKE ...@@ -187,6 +187,19 @@ config OMAP_SERIAL_WAKE
to data on the serial RX line. This allows you to wake the to data on the serial RX line. This allows you to wake the
system from serial console. system from serial console.
choice
prompt "OMAP PM layer selection"
depends on ARCH_OMAP
default OMAP_PM_NOOP
config OMAP_PM_NONE
bool "No PM layer"
config OMAP_PM_NOOP
bool "No-op/debug PM layer"
endchoice
endmenu endmenu
endif endif
...@@ -26,3 +26,4 @@ obj-y += $(i2c-omap-m) $(i2c-omap-y) ...@@ -26,3 +26,4 @@ obj-y += $(i2c-omap-m) $(i2c-omap-y)
# OMAP mailbox framework # OMAP mailbox framework
obj-$(CONFIG_OMAP_MBOX_FWK) += mailbox.o obj-$(CONFIG_OMAP_MBOX_FWK) += mailbox.o
obj-$(CONFIG_OMAP_PM_NOOP) += omap-pm-noop.o
\ No newline at end of file
This diff is collapsed.
/*
* omap-pm-noop.c - OMAP power management interface - dummy version
*
* This code implements the OMAP power management interface to
* drivers, CPUIdle, CPUFreq, and DSP Bridge. It is strictly for
* debug/demonstration use, as it does nothing but printk() whenever a
* function is called (when DEBUG is defined, below)
*
* Copyright (C) 2008-2009 Texas Instruments, Inc.
* Copyright (C) 2008-2009 Nokia Corporation
* Paul Walmsley
*
* Interface developed by (in alphabetical order):
* Karthik Dasu, Tony Lindgren, Rajendra Nayak, Sakari Poussa, Veeramanikandan
* Raju, Anand Sawant, Igor Stoppa, Paul Walmsley, Richard Woodruff
*/
#undef DEBUG
#include <linux/init.h>
#include <linux/cpufreq.h>
#include <linux/device.h>
/* Interface documentation is in mach/omap-pm.h */
#include <mach/omap-pm.h>
#include <mach/powerdomain.h>
struct omap_opp *dsp_opps;
struct omap_opp *mpu_opps;
struct omap_opp *l3_opps;
/*
* Device-driver-originated constraints (via board-*.c files)
*/
void omap_pm_set_max_mpu_wakeup_lat(struct device *dev, long t)
{
if (!dev || t < -1) {
WARN_ON(1);
return;
};
if (t == -1)
pr_debug("OMAP PM: remove max MPU wakeup latency constraint: "
"dev %s\n", dev_name(dev));
else
pr_debug("OMAP PM: add max MPU wakeup latency constraint: "
"dev %s, t = %ld usec\n", dev_name(dev), t);
/*
* For current Linux, this needs to map the MPU to a
* powerdomain, then go through the list of current max lat
* constraints on the MPU and find the smallest. If
* the latency constraint has changed, the code should
* recompute the state to enter for the next powerdomain
* state.
*
* TI CDP code can call constraint_set here.
*/
}
void omap_pm_set_min_bus_tput(struct device *dev, u8 agent_id, unsigned long r)
{
if (!dev || (agent_id != OCP_INITIATOR_AGENT &&
agent_id != OCP_TARGET_AGENT)) {
WARN_ON(1);
return;
};
if (r == 0)
pr_debug("OMAP PM: remove min bus tput constraint: "
"dev %s for agent_id %d\n", dev_name(dev), agent_id);
else
pr_debug("OMAP PM: add min bus tput constraint: "
"dev %s for agent_id %d: rate %ld KiB\n",
dev_name(dev), agent_id, r);
/*
* This code should model the interconnect and compute the
* required clock frequency, convert that to a VDD2 OPP ID, then
* set the VDD2 OPP appropriately.
*
* TI CDP code can call constraint_set here on the VDD2 OPP.
*/
}
void omap_pm_set_max_dev_wakeup_lat(struct device *dev, long t)
{
if (!dev || t < -1) {
WARN_ON(1);
return;
};
if (t == -1)
pr_debug("OMAP PM: remove max device latency constraint: "
"dev %s\n", dev_name(dev));
else
pr_debug("OMAP PM: add max device latency constraint: "
"dev %s, t = %ld usec\n", dev_name(dev), t);
/*
* For current Linux, this needs to map the device to a
* powerdomain, then go through the list of current max lat
* constraints on that powerdomain and find the smallest. If
* the latency constraint has changed, the code should
* recompute the state to enter for the next powerdomain
* state. Conceivably, this code should also determine
* whether to actually disable the device clocks or not,
* depending on how long it takes to re-enable the clocks.
*
* TI CDP code can call constraint_set here.
*/
}
void omap_pm_set_max_sdma_lat(struct device *dev, long t)
{
if (!dev || t < -1) {
WARN_ON(1);
return;
};
if (t == -1)
pr_debug("OMAP PM: remove max DMA latency constraint: "
"dev %s\n", dev_name(dev));
else
pr_debug("OMAP PM: add max DMA latency constraint: "
"dev %s, t = %ld usec\n", dev_name(dev), t);
/*
* For current Linux PM QOS params, this code should scan the
* list of maximum CPU and DMA latencies and select the
* smallest, then set cpu_dma_latency pm_qos_param
* accordingly.
*
* For future Linux PM QOS params, with separate CPU and DMA
* latency params, this code should just set the dma_latency param.
*
* TI CDP code can call constraint_set here.
*/
}
/*
* DSP Bridge-specific constraints
*/
const struct omap_opp *omap_pm_dsp_get_opp_table(void)
{
pr_debug("OMAP PM: DSP request for OPP table\n");
/*
* Return DSP frequency table here: The final item in the
* array should have .rate = .opp_id = 0.
*/
return NULL;
}
void omap_pm_dsp_set_min_opp(u8 opp_id)
{
if (opp_id == 0) {
WARN_ON(1);
return;
}
pr_debug("OMAP PM: DSP requests minimum VDD1 OPP to be %d\n", opp_id);
/*
*
* For l-o dev tree, our VDD1 clk is keyed on OPP ID, so we
* can just test to see which is higher, the CPU's desired OPP
* ID or the DSP's desired OPP ID, and use whichever is
* highest.
*
* In CDP12.14+, the VDD1 OPP custom clock that controls the DSP
* rate is keyed on MPU speed, not the OPP ID. So we need to
* map the OPP ID to the MPU speed for use with clk_set_rate()
* if it is higher than the current OPP clock rate.
*
*/
}
u8 omap_pm_dsp_get_opp(void)
{
pr_debug("OMAP PM: DSP requests current DSP OPP ID\n");
/*
* For l-o dev tree, call clk_get_rate() on VDD1 OPP clock
*
* CDP12.14+:
* Call clk_get_rate() on the OPP custom clock, map that to an
* OPP ID using the tables defined in board-*.c/chip-*.c files.
*/
return 0;
}
/*
* CPUFreq-originated constraint
*
* In the future, this should be handled by custom OPP clocktype
* functions.
*/
struct cpufreq_frequency_table **omap_pm_cpu_get_freq_table(void)
{
pr_debug("OMAP PM: CPUFreq request for frequency table\n");
/*
* Return CPUFreq frequency table here: loop over
* all VDD1 clkrates, pull out the mpu_ck frequencies, build
* table
*/
return NULL;
}
void omap_pm_cpu_set_freq(unsigned long f)
{
if (f == 0) {
WARN_ON(1);
return;
}
pr_debug("OMAP PM: CPUFreq requests CPU frequency to be set to %lu\n",
f);
/*
* For l-o dev tree, determine whether MPU freq or DSP OPP id
* freq is higher. Find the OPP ID corresponding to the
* higher frequency. Call clk_round_rate() and clk_set_rate()
* on the OPP custom clock.
*
* CDP should just be able to set the VDD1 OPP clock rate here.
*/
}
unsigned long omap_pm_cpu_get_freq(void)
{
pr_debug("OMAP PM: CPUFreq requests current CPU frequency\n");
/*
* Call clk_get_rate() on the mpu_ck.
*/
return 0;
}
/*
* Device context loss tracking
*/
int omap_pm_get_dev_context_loss_count(struct device *dev)
{
if (!dev) {
WARN_ON(1);
return -EINVAL;
};
pr_debug("OMAP PM: returning context loss count for dev %s\n",
dev_name(dev));
/*
* Map the device to the powerdomain. Return the powerdomain
* off counter.
*/
return 0;
}
/* Should be called before clk framework init */
int __init omap_pm_if_early_init(struct omap_opp *mpu_opp_table,
struct omap_opp *dsp_opp_table,
struct omap_opp *l3_opp_table)
{
mpu_opps = mpu_opp_table;
dsp_opps = dsp_opp_table;
l3_opps = l3_opp_table;
return 0;
}
/* Must be called after clock framework is initialized */
int __init omap_pm_if_init(void)
{
return 0;
}
void omap_pm_if_exit(void)
{
/* Deallocate CPUFreq frequency table here */
}
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