9799aca203
First, this patch adds new worst-case latency values to the omap_device_pm_latency struct. Here the worst-case measured latencies for the activate and deactivate hooks are stored. In addition, add an option to auto-adjust the latency values used for device activate/deactivate. By setting a new 'OMAP_DEVICE_LATENCY_AUTO_ADJUST' flag in the omap_device_pm_latency struct, the omap_device layer automatically adjusts the activate/deactivate latencies to the worst-case measured values. Anytime a new worst-case value is found, it is printed to the console. Here is an example log during boot using UART2 s an example. After boot, the OPP is manually changed to the 125MHz OPP: [...] Freeing init memory: 128K omap_device: serial8250.2: new worst case deactivate latency 0: 30517 omap_device: serial8250.2: new worst case activate latency 0: 30517 omap_device: serial8250.2: new worst case activate latency 0: 218139648 omap_device: serial8250.2: new worst case deactivate latency 0: 61035 omap_device: serial8250.2: new worst case activate latency 0: 278076171 omap_device: serial8250.2: new worst case activate latency 0: 298614501 omap_device: serial8250.2: new worst case activate latency 0: 327331542 / # echo 125000 > /sys/devices/system/cpu/cpu0/cpufreq/scaling_setspeed omap_device: serial8250.2: new worst case deactivate latency 0: 91552 Motivation: this can be used as a technique to automatically determine the worst case latency values. The current method of printing a warning on every violation is too noisy to actually interact the console in order to set low OPP to discover latencies. Another motivation for this patch is that the activate/deactivate latenices can vary depending on the idlemode of the device. While working on the UARTs, I noticed that when using no-idle, the activate latencies were as high as several hundred msecs as shown above. When the UARTs are in smart-idle, the max latency is well under 100 usecs. Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com> Signed-off-by: Paul Walmsley <paul@pwsan.com>
148 lines
4.7 KiB
C
148 lines
4.7 KiB
C
/*
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* omap_device headers
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*
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* Copyright (C) 2009 Nokia Corporation
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* Paul Walmsley
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*
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* Developed in collaboration with (alphabetical order): Benoit
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* Cousson, Kevin Hilman, Tony Lindgren, Rajendra Nayak, Vikram
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* Pandita, Sakari Poussa, Anand Sawant, Santosh Shilimkar, Richard
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* Woodruff
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License version 2 as
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* published by the Free Software Foundation.
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*
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* Eventually this type of functionality should either be
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* a) implemented via arch-specific pointers in platform_device
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* or
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* b) implemented as a proper omap_bus/omap_device in Linux, no more
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* platform_device
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*
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* omap_device differs from omap_hwmod in that it includes external
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* (e.g., board- and system-level) integration details. omap_hwmod
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* stores hardware data that is invariant for a given OMAP chip.
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*
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* To do:
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* - GPIO integration
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* - regulator integration
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*
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*/
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#ifndef __ARCH_ARM_PLAT_OMAP_INCLUDE_MACH_OMAP_DEVICE_H
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#define __ARCH_ARM_PLAT_OMAP_INCLUDE_MACH_OMAP_DEVICE_H
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#include <linux/kernel.h>
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#include <linux/platform_device.h>
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#include <plat/omap_hwmod.h>
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/* omap_device._state values */
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#define OMAP_DEVICE_STATE_UNKNOWN 0
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#define OMAP_DEVICE_STATE_ENABLED 1
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#define OMAP_DEVICE_STATE_IDLE 2
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#define OMAP_DEVICE_STATE_SHUTDOWN 3
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/**
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* struct omap_device - omap_device wrapper for platform_devices
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* @pdev: platform_device
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* @hwmods: (one .. many per omap_device)
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* @hwmods_cnt: ARRAY_SIZE() of @hwmods
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* @pm_lats: ptr to an omap_device_pm_latency table
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* @pm_lats_cnt: ARRAY_SIZE() of what is passed to @pm_lats
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* @pm_lat_level: array index of the last odpl entry executed - -1 if never
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* @dev_wakeup_lat: dev wakeup latency in nanoseconds
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* @_dev_wakeup_lat_limit: dev wakeup latency limit in nsec - set by OMAP PM
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* @_state: one of OMAP_DEVICE_STATE_* (see above)
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* @flags: device flags
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*
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* Integrates omap_hwmod data into Linux platform_device.
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*
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* Field names beginning with underscores are for the internal use of
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* the omap_device code.
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*
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*/
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struct omap_device {
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struct platform_device pdev;
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struct omap_hwmod **hwmods;
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struct omap_device_pm_latency *pm_lats;
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u32 dev_wakeup_lat;
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u32 _dev_wakeup_lat_limit;
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u8 pm_lats_cnt;
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s8 pm_lat_level;
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u8 hwmods_cnt;
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u8 _state;
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};
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/* Device driver interface (call via platform_data fn ptrs) */
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int omap_device_enable(struct platform_device *pdev);
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int omap_device_idle(struct platform_device *pdev);
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int omap_device_shutdown(struct platform_device *pdev);
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/* Core code interface */
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int omap_device_count_resources(struct omap_device *od);
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int omap_device_fill_resources(struct omap_device *od, struct resource *res);
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struct omap_device *omap_device_build(const char *pdev_name, int pdev_id,
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struct omap_hwmod *oh, void *pdata,
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int pdata_len,
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struct omap_device_pm_latency *pm_lats,
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int pm_lats_cnt);
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struct omap_device *omap_device_build_ss(const char *pdev_name, int pdev_id,
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struct omap_hwmod **oh, int oh_cnt,
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void *pdata, int pdata_len,
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struct omap_device_pm_latency *pm_lats,
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int pm_lats_cnt);
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int omap_device_register(struct omap_device *od);
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/* OMAP PM interface */
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int omap_device_align_pm_lat(struct platform_device *pdev,
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u32 new_wakeup_lat_limit);
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struct powerdomain *omap_device_get_pwrdm(struct omap_device *od);
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/* Other */
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int omap_device_idle_hwmods(struct omap_device *od);
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int omap_device_enable_hwmods(struct omap_device *od);
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int omap_device_disable_clocks(struct omap_device *od);
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int omap_device_enable_clocks(struct omap_device *od);
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/*
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* Entries should be kept in latency order ascending
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*
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* deact_lat is the maximum number of microseconds required to complete
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* deactivate_func() at the device's slowest OPP.
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*
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* act_lat is the maximum number of microseconds required to complete
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* activate_func() at the device's slowest OPP.
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*
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* This will result in some suboptimal power management decisions at fast
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* OPPs, but avoids having to recompute all device power management decisions
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* if the system shifts from a fast OPP to a slow OPP (in order to meet
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* latency requirements).
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*
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* XXX should deactivate_func/activate_func() take platform_device pointers
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* rather than omap_device pointers?
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*/
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struct omap_device_pm_latency {
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u32 deactivate_lat;
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u32 deactivate_lat_worst;
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int (*deactivate_func)(struct omap_device *od);
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u32 activate_lat;
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u32 activate_lat_worst;
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int (*activate_func)(struct omap_device *od);
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u32 flags;
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};
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#define OMAP_DEVICE_LATENCY_AUTO_ADJUST BIT(1)
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/* Get omap_device pointer from platform_device pointer */
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#define to_omap_device(x) container_of((x), struct omap_device, pdev)
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#endif
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