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![Victor Gallardo](/assets/img/avatar_default.png)
Add suspend/resume support for 4xx compatible CPUs. See /sys/power/state for available power states configured in. Add two different idle states (idle-wait and idle-doze) controlled via sysfs. Default is idle-wait. cat /sys/devices/system/cpu/cpu0/idle [wait] doze To save additional power, use idle-doze. echo doze > /sys/devices/system/cpu/cpu0/idle cat /sys/devices/system/cpu/cpu0/idle wait [doze] Signed-off-by: Victor Gallardo <vgallardo@apm.com> Signed-off-by: Josh Boyer <jwboyer@linux.vnet.ibm.com>
346 lines
7.6 KiB
C
346 lines
7.6 KiB
C
/*
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* PowerPC 4xx Clock and Power Management
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*
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* Copyright (C) 2010, Applied Micro Circuits Corporation
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* Victor Gallardo (vgallardo@apm.com)
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*
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* Based on arch/powerpc/platforms/44x/idle.c:
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* Jerone Young <jyoung5@us.ibm.com>
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* Copyright 2008 IBM Corp.
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*
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* Based on arch/powerpc/sysdev/fsl_pmc.c:
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* Anton Vorontsov <avorontsov@ru.mvista.com>
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* Copyright 2009 MontaVista Software, Inc.
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*
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* See file CREDITS for list of people who contributed to this
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* project.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2 of
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* the License, or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston,
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* MA 02111-1307 USA
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*/
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#include <linux/kernel.h>
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#include <linux/of_platform.h>
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#include <linux/sysfs.h>
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#include <linux/cpu.h>
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#include <linux/suspend.h>
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#include <asm/dcr.h>
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#include <asm/dcr-native.h>
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#include <asm/machdep.h>
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#define CPM_ER 0
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#define CPM_FR 1
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#define CPM_SR 2
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#define CPM_IDLE_WAIT 0
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#define CPM_IDLE_DOZE 1
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struct cpm {
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dcr_host_t dcr_host;
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unsigned int dcr_offset[3];
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unsigned int powersave_off;
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unsigned int unused;
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unsigned int idle_doze;
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unsigned int standby;
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unsigned int suspend;
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};
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static struct cpm cpm;
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struct cpm_idle_mode {
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unsigned int enabled;
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const char *name;
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};
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static struct cpm_idle_mode idle_mode[] = {
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[CPM_IDLE_WAIT] = { 1, "wait" }, /* default */
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[CPM_IDLE_DOZE] = { 0, "doze" },
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};
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static unsigned int cpm_set(unsigned int cpm_reg, unsigned int mask)
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{
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unsigned int value;
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/* CPM controller supports 3 different types of sleep interface
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* known as class 1, 2 and 3. For class 1 units, they are
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* unconditionally put to sleep when the corresponding CPM bit is
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* set. For class 2 and 3 units this is not case; if they can be
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* put to to sleep, they will. Here we do not verify, we just
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* set them and expect them to eventually go off when they can.
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*/
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value = dcr_read(cpm.dcr_host, cpm.dcr_offset[cpm_reg]);
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dcr_write(cpm.dcr_host, cpm.dcr_offset[cpm_reg], value | mask);
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/* return old state, to restore later if needed */
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return value;
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}
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static void cpm_idle_wait(void)
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{
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unsigned long msr_save;
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/* save off initial state */
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msr_save = mfmsr();
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/* sync required when CPM0_ER[CPU] is set */
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mb();
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/* set wait state MSR */
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mtmsr(msr_save|MSR_WE|MSR_EE|MSR_CE|MSR_DE);
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isync();
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/* return to initial state */
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mtmsr(msr_save);
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isync();
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}
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static void cpm_idle_sleep(unsigned int mask)
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{
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unsigned int er_save;
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/* update CPM_ER state */
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er_save = cpm_set(CPM_ER, mask);
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/* go to wait state so that CPM0_ER[CPU] can take effect */
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cpm_idle_wait();
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/* restore CPM_ER state */
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dcr_write(cpm.dcr_host, cpm.dcr_offset[CPM_ER], er_save);
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}
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static void cpm_idle_doze(void)
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{
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cpm_idle_sleep(cpm.idle_doze);
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}
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static void cpm_idle_config(int mode)
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{
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int i;
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if (idle_mode[mode].enabled)
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return;
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for (i = 0; i < ARRAY_SIZE(idle_mode); i++)
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idle_mode[i].enabled = 0;
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idle_mode[mode].enabled = 1;
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}
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static ssize_t cpm_idle_show(struct kobject *kobj,
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struct kobj_attribute *attr, char *buf)
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{
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char *s = buf;
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int i;
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for (i = 0; i < ARRAY_SIZE(idle_mode); i++) {
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if (idle_mode[i].enabled)
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s += sprintf(s, "[%s] ", idle_mode[i].name);
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else
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s += sprintf(s, "%s ", idle_mode[i].name);
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}
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*(s-1) = '\n'; /* convert the last space to a newline */
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return s - buf;
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}
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static ssize_t cpm_idle_store(struct kobject *kobj,
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struct kobj_attribute *attr,
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const char *buf, size_t n)
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{
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int i;
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char *p;
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int len;
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p = memchr(buf, '\n', n);
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len = p ? p - buf : n;
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for (i = 0; i < ARRAY_SIZE(idle_mode); i++) {
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if (strncmp(buf, idle_mode[i].name, len) == 0) {
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cpm_idle_config(i);
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return n;
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}
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}
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return -EINVAL;
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}
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static struct kobj_attribute cpm_idle_attr =
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__ATTR(idle, 0644, cpm_idle_show, cpm_idle_store);
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static void cpm_idle_config_sysfs(void)
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{
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struct sys_device *sys_dev;
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unsigned long ret;
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sys_dev = get_cpu_sysdev(0);
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ret = sysfs_create_file(&sys_dev->kobj,
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&cpm_idle_attr.attr);
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if (ret)
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printk(KERN_WARNING
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"cpm: failed to create idle sysfs entry\n");
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}
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static void cpm_idle(void)
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{
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if (idle_mode[CPM_IDLE_DOZE].enabled)
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cpm_idle_doze();
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else
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cpm_idle_wait();
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}
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static int cpm_suspend_valid(suspend_state_t state)
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{
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switch (state) {
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case PM_SUSPEND_STANDBY:
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return !!cpm.standby;
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case PM_SUSPEND_MEM:
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return !!cpm.suspend;
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default:
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return 0;
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}
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}
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static void cpm_suspend_standby(unsigned int mask)
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{
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unsigned long tcr_save;
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/* disable decrement interrupt */
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tcr_save = mfspr(SPRN_TCR);
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mtspr(SPRN_TCR, tcr_save & ~TCR_DIE);
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/* go to sleep state */
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cpm_idle_sleep(mask);
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/* restore decrement interrupt */
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mtspr(SPRN_TCR, tcr_save);
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}
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static int cpm_suspend_enter(suspend_state_t state)
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{
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switch (state) {
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case PM_SUSPEND_STANDBY:
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cpm_suspend_standby(cpm.standby);
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break;
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case PM_SUSPEND_MEM:
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cpm_suspend_standby(cpm.suspend);
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break;
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}
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return 0;
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}
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static struct platform_suspend_ops cpm_suspend_ops = {
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.valid = cpm_suspend_valid,
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.enter = cpm_suspend_enter,
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};
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static int cpm_get_uint_property(struct device_node *np,
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const char *name)
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{
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int len;
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const unsigned int *prop = of_get_property(np, name, &len);
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if (prop == NULL || len < sizeof(u32))
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return 0;
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return *prop;
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}
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static int __init cpm_init(void)
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{
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struct device_node *np;
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int dcr_base, dcr_len;
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int ret = 0;
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if (!cpm.powersave_off) {
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cpm_idle_config(CPM_IDLE_WAIT);
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ppc_md.power_save = &cpm_idle;
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}
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np = of_find_compatible_node(NULL, NULL, "ibm,cpm");
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if (!np) {
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ret = -EINVAL;
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goto out;
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}
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dcr_base = dcr_resource_start(np, 0);
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dcr_len = dcr_resource_len(np, 0);
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if (dcr_base == 0 || dcr_len == 0) {
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printk(KERN_ERR "cpm: could not parse dcr property for %s\n",
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np->full_name);
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ret = -EINVAL;
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goto out;
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}
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cpm.dcr_host = dcr_map(np, dcr_base, dcr_len);
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if (!DCR_MAP_OK(cpm.dcr_host)) {
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printk(KERN_ERR "cpm: failed to map dcr property for %s\n",
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np->full_name);
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ret = -EINVAL;
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goto out;
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}
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/* All 4xx SoCs with a CPM controller have one of two
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* different order for the CPM registers. Some have the
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* CPM registers in the following order (ER,FR,SR). The
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* others have them in the following order (SR,ER,FR).
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*/
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if (cpm_get_uint_property(np, "er-offset") == 0) {
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cpm.dcr_offset[CPM_ER] = 0;
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cpm.dcr_offset[CPM_FR] = 1;
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cpm.dcr_offset[CPM_SR] = 2;
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} else {
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cpm.dcr_offset[CPM_ER] = 1;
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cpm.dcr_offset[CPM_FR] = 2;
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cpm.dcr_offset[CPM_SR] = 0;
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}
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/* Now let's see what IPs to turn off for the following modes */
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cpm.unused = cpm_get_uint_property(np, "unused-units");
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cpm.idle_doze = cpm_get_uint_property(np, "idle-doze");
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cpm.standby = cpm_get_uint_property(np, "standby");
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cpm.suspend = cpm_get_uint_property(np, "suspend");
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/* If some IPs are unused let's turn them off now */
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if (cpm.unused) {
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cpm_set(CPM_ER, cpm.unused);
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cpm_set(CPM_FR, cpm.unused);
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}
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/* Now let's export interfaces */
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if (!cpm.powersave_off && cpm.idle_doze)
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cpm_idle_config_sysfs();
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if (cpm.standby || cpm.suspend)
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suspend_set_ops(&cpm_suspend_ops);
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out:
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if (np)
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of_node_put(np);
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return ret;
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}
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late_initcall(cpm_init);
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static int __init cpm_powersave_off(char *arg)
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{
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cpm.powersave_off = 1;
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return 0;
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}
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__setup("powersave=off", cpm_powersave_off);
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