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Message-Id: <1352330622-13616-1-git-send-email-robherring2@gmail.com>
Date: Wed, 7 Nov 2012 17:23:42 -0600
From: Rob Herring <robherring2@...il.com>
To: linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org
Cc: Arnd Bergmann <arnd@...db.de>, Olof Johansson <olof@...om.net>,
Rob Herring <rob.herring@...xeda.com>,
Len Brown <len.brown@...el.com>,
"Rafael J. Wysocki" <rjw@...k.pl>
Subject: [PATCH] cpuidle: add Calxeda SOC idle support
From: Rob Herring <rob.herring@...xeda.com>
Add support for core powergating on Calxeda platforms. Initially, this
supports ECX-1000 (highbank), but support will be added for ECX-2000
later.
Signed-off-by: Rob Herring <rob.herring@...xeda.com>
Cc: Len Brown <len.brown@...el.com>
Cc: "Rafael J. Wysocki" <rjw@...k.pl>
---
It's not really clear where we want ARM cpuidle drivers. We're moving
everything else out of arch/arm, and my understanding is Len doesn't want
them in drivers/idle. It seems kind of silly to me to have the framework
and drivers in 2 places. I've put this in drivers/cpuidle, but it doesn't
make any difference to me.
Rob
drivers/cpuidle/Kconfig | 10 +++
drivers/cpuidle/Makefile | 2 +
drivers/cpuidle/cpuidle-calxeda.c | 161 +++++++++++++++++++++++++++++++++++++
3 files changed, 173 insertions(+)
create mode 100644 drivers/cpuidle/cpuidle-calxeda.c
diff --git a/drivers/cpuidle/Kconfig b/drivers/cpuidle/Kconfig
index a76b689..d2d007b 100644
--- a/drivers/cpuidle/Kconfig
+++ b/drivers/cpuidle/Kconfig
@@ -21,3 +21,13 @@ config CPU_IDLE_GOV_MENU
config ARCH_NEEDS_CPU_IDLE_COUPLED
def_bool n
+
+if CPU_IDLE
+
+config CPU_IDLE_CALXEDA
+ bool "CPU Idle Driver for Calxeda processors"
+ depends on ARCH_HIGHBANK
+ help
+ Select this to enable cpuidle on Calxeda processors.
+
+endif
diff --git a/drivers/cpuidle/Makefile b/drivers/cpuidle/Makefile
index 38c8f69..03ee874 100644
--- a/drivers/cpuidle/Makefile
+++ b/drivers/cpuidle/Makefile
@@ -4,3 +4,5 @@
obj-y += cpuidle.o driver.o governor.o sysfs.o governors/
obj-$(CONFIG_ARCH_NEEDS_CPU_IDLE_COUPLED) += coupled.o
+
+obj-$(CONFIG_CPU_IDLE_CALXEDA) += cpuidle-calxeda.o
diff --git a/drivers/cpuidle/cpuidle-calxeda.c b/drivers/cpuidle/cpuidle-calxeda.c
new file mode 100644
index 0000000..e1aab38
--- /dev/null
+++ b/drivers/cpuidle/cpuidle-calxeda.c
@@ -0,0 +1,161 @@
+/*
+ * Copyright 2012 Calxeda, Inc.
+ *
+ * Based on arch/arm/plat-mxc/cpuidle.c:
+ * Copyright 2012 Freescale Semiconductor, Inc.
+ * Copyright 2012 Linaro Ltd.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License along with
+ * this program. If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/cpuidle.h>
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/time.h>
+#include <linux/delay.h>
+#include <linux/suspend.h>
+#include <asm/cpuidle.h>
+#include <asm/proc-fns.h>
+#include <asm/smp_scu.h>
+#include <asm/suspend.h>
+#include <asm/cacheflush.h>
+#include <asm/cp15.h>
+
+extern void highbank_set_cpu_jump(int cpu, void *jump_addr);
+extern void *scu_base_addr;
+
+static struct cpuidle_device __percpu *calxeda_idle_cpuidle_devices;
+
+static inline unsigned int get_auxcr(void)
+{
+ unsigned int val;
+ asm("mrc p15, 0, %0, c1, c0, 1 @ get AUXCR" : "=r" (val) : : "cc");
+ return val;
+}
+
+static inline void set_auxcr(unsigned int val)
+{
+ asm volatile("mcr p15, 0, %0, c1, c0, 1 @ set AUXCR"
+ : : "r" (val) : "cc");
+ isb();
+}
+
+static noinline void calxeda_idle_restore(void)
+{
+ set_cr(get_cr() | CR_C);
+ set_auxcr(get_auxcr() | 0x40);
+ scu_power_mode(scu_base_addr, SCU_PM_NORMAL);
+}
+
+static int calxeda_idle_finish(unsigned long val)
+{
+ /* Already flushed cache, but do it again as the outer cache functions
+ * dirty the cache with spinlocks */
+ flush_cache_all();
+
+ set_auxcr(get_auxcr() & ~0x40);
+ set_cr(get_cr() & ~CR_C);
+
+ scu_power_mode(scu_base_addr, SCU_PM_DORMANT);
+
+ cpu_do_idle();
+
+ /* Restore things if we didn't enter power-gating */
+ calxeda_idle_restore();
+ return 1;
+}
+
+static int calxeda_pwrdown_idle(struct cpuidle_device *dev,
+ struct cpuidle_driver *drv,
+ int index)
+{
+ highbank_set_cpu_jump(smp_processor_id(), cpu_resume);
+ cpu_suspend(0, calxeda_idle_finish);
+ return index;
+}
+
+static void calxeda_idle_cpuidle_devices_uninit(void)
+{
+ int i;
+ struct cpuidle_device *dev;
+
+ for_each_possible_cpu(i) {
+ dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, i);
+ cpuidle_unregister_device(dev);
+ }
+
+ free_percpu(calxeda_idle_cpuidle_devices);
+}
+
+static struct cpuidle_driver calxeda_idle_driver = {
+ .name = "calxeda_idle",
+ .en_core_tk_irqen = 1,
+ .states = {
+ ARM_CPUIDLE_WFI_STATE,
+ {
+ .name = "PG",
+ .desc = "Power Gate",
+ .flags = CPUIDLE_FLAG_TIME_VALID,
+ .exit_latency = 30,
+ .power_usage = 50,
+ .target_residency = 200,
+ .enter = calxeda_pwrdown_idle,
+ },
+ },
+ .state_count = 2,
+};
+
+static int __init calxeda_cpuidle_init(void)
+{
+ int cpu_id;
+ int ret;
+ struct cpuidle_device *dev;
+ struct cpuidle_driver *drv = &calxeda_idle_driver;
+
+ if (!of_machine_is_compatible("calxeda,highbank"))
+ return -ENODEV;
+
+ ret = cpuidle_register_driver(drv);
+ if (ret)
+ return ret;
+
+ calxeda_idle_cpuidle_devices = alloc_percpu(struct cpuidle_device);
+ if (calxeda_idle_cpuidle_devices == NULL) {
+ ret = -ENOMEM;
+ goto unregister_drv;
+ }
+
+ /* initialize state data for each cpuidle_device */
+ for_each_possible_cpu(cpu_id) {
+ dev = per_cpu_ptr(calxeda_idle_cpuidle_devices, cpu_id);
+ dev->cpu = cpu_id;
+ dev->state_count = drv->state_count;
+
+ ret = cpuidle_register_device(dev);
+ if (ret) {
+ pr_err("Failed to register cpu %u, error: %d\n",
+ cpu_id, ret);
+ goto uninit;
+ }
+ }
+
+ return 0;
+
+uninit:
+ calxeda_idle_cpuidle_devices_uninit();
+unregister_drv:
+ cpuidle_unregister_driver(drv);
+ return ret;
+}
+module_init(calxeda_cpuidle_init);
--
1.7.10.4
--
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