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authorRabeeh Khoury <rabeeh@marvell.com>2009-03-24 16:10:15 +0200
committerNicolas Pitre <nico@cam.org>2009-06-08 13:04:41 -0400
commite50b6befae9ea91c2d190fb78ff1e06a0b950add (patch)
tree28f12968f6564d87a9e1c158d40ce4dbd1271d9a /arch/arm/mach-kirkwood
parenta914d4309c4cf6e7c4d0dbce4822dcad38a7cf27 (diff)
downloadop-kernel-dev-e50b6befae9ea91c2d190fb78ff1e06a0b950add.zip
op-kernel-dev-e50b6befae9ea91c2d190fb78ff1e06a0b950add.tar.gz
[ARM] Kirkwood: CPU idle driver
The patch adds support for Kirkwood cpu idle. Two idle states are defined: 1. Wait-for-interrupt (replacing default kirkwood wfi) 2. Wait-for-interrupt and DDR self refresh Signed-off-by: Rabeeh Khoury <rabeeh@marvell.com> Signed-off-by: Nicolas Pitre <nico@marvell.com>
Diffstat (limited to 'arch/arm/mach-kirkwood')
-rw-r--r--arch/arm/mach-kirkwood/Makefile2
-rw-r--r--arch/arm/mach-kirkwood/cpuidle.c96
-rw-r--r--arch/arm/mach-kirkwood/include/mach/kirkwood.h1
3 files changed, 99 insertions, 0 deletions
diff --git a/arch/arm/mach-kirkwood/Makefile b/arch/arm/mach-kirkwood/Makefile
index 8f03c9b..f21f35d 100644
--- a/arch/arm/mach-kirkwood/Makefile
+++ b/arch/arm/mach-kirkwood/Makefile
@@ -5,3 +5,5 @@ obj-$(CONFIG_MACH_RD88F6192_NAS) += rd88f6192-nas-setup.o
obj-$(CONFIG_MACH_RD88F6281) += rd88f6281-setup.o
obj-$(CONFIG_MACH_SHEEVAPLUG) += sheevaplug-setup.o
obj-$(CONFIG_MACH_TS219) += ts219-setup.o
+
+obj-$(CONFIG_CPU_IDLE) += cpuidle.o
diff --git a/arch/arm/mach-kirkwood/cpuidle.c b/arch/arm/mach-kirkwood/cpuidle.c
new file mode 100644
index 0000000..f68d33f
--- /dev/null
+++ b/arch/arm/mach-kirkwood/cpuidle.c
@@ -0,0 +1,96 @@
+/*
+ * arch/arm/mach-kirkwood/cpuidle.c
+ *
+ * CPU idle Marvell Kirkwood SoCs
+ *
+ * This file is licensed under the terms of the GNU General Public
+ * License version 2. This program is licensed "as is" without any
+ * warranty of any kind, whether express or implied.
+ *
+ * The cpu idle uses wait-for-interrupt and DDR self refresh in order
+ * to implement two idle states -
+ * #1 wait-for-interrupt
+ * #2 wait-for-interrupt and DDR self refresh
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/cpuidle.h>
+#include <linux/io.h>
+#include <asm/proc-fns.h>
+#include <mach/kirkwood.h>
+
+#define KIRKWOOD_MAX_STATES 2
+
+static struct cpuidle_driver kirkwood_idle_driver = {
+ .name = "kirkwood_idle",
+ .owner = THIS_MODULE,
+};
+
+static DEFINE_PER_CPU(struct cpuidle_device, kirkwood_cpuidle_device);
+
+/* Actual code that puts the SoC in different idle states */
+static int kirkwood_enter_idle(struct cpuidle_device *dev,
+ struct cpuidle_state *state)
+{
+ struct timeval before, after;
+ int idle_time;
+
+ local_irq_disable();
+ do_gettimeofday(&before);
+ if (state == &dev->states[0])
+ /* Wait for interrupt state */
+ cpu_do_idle();
+ else if (state == &dev->states[1]) {
+ /*
+ * Following write will put DDR in self refresh.
+ * Note that we have 256 cycles before DDR puts it
+ * self in self-refresh, so the wait-for-interrupt
+ * call afterwards won't get the DDR from self refresh
+ * mode.
+ */
+ writel(0x7, DDR_OPERATION_BASE);
+ cpu_do_idle();
+ }
+ do_gettimeofday(&after);
+ local_irq_enable();
+ idle_time = (after.tv_sec - before.tv_sec) * USEC_PER_SEC +
+ (after.tv_usec - before.tv_usec);
+ return idle_time;
+}
+
+/* Initialize CPU idle by registering the idle states */
+static int kirkwood_init_cpuidle(void)
+{
+ struct cpuidle_device *device;
+
+ cpuidle_register_driver(&kirkwood_idle_driver);
+
+ device = &per_cpu(kirkwood_cpuidle_device, smp_processor_id());
+ device->state_count = KIRKWOOD_MAX_STATES;
+
+ /* Wait for interrupt state */
+ device->states[0].enter = kirkwood_enter_idle;
+ device->states[0].exit_latency = 1;
+ device->states[0].target_residency = 10000;
+ device->states[0].flags = CPUIDLE_FLAG_TIME_VALID;
+ strcpy(device->states[0].name, "WFI");
+ strcpy(device->states[0].desc, "Wait for interrupt");
+
+ /* Wait for interrupt and DDR self refresh state */
+ device->states[1].enter = kirkwood_enter_idle;
+ device->states[1].exit_latency = 10;
+ device->states[1].target_residency = 10000;
+ device->states[1].flags = CPUIDLE_FLAG_TIME_VALID;
+ strcpy(device->states[1].name, "DDR SR");
+ strcpy(device->states[1].desc, "WFI and DDR Self Refresh");
+
+ if (cpuidle_register_device(device)) {
+ printk(KERN_ERR "kirkwood_init_cpuidle: Failed registering\n");
+ return -EIO;
+ }
+ return 0;
+}
+
+device_initcall(kirkwood_init_cpuidle);
diff --git a/arch/arm/mach-kirkwood/include/mach/kirkwood.h b/arch/arm/mach-kirkwood/include/mach/kirkwood.h
index b3e1395..f20ff64 100644
--- a/arch/arm/mach-kirkwood/include/mach/kirkwood.h
+++ b/arch/arm/mach-kirkwood/include/mach/kirkwood.h
@@ -48,6 +48,7 @@
*/
#define DDR_VIRT_BASE (KIRKWOOD_REGS_VIRT_BASE | 0x00000)
#define DDR_WINDOW_CPU_BASE (DDR_VIRT_BASE | 0x1500)
+#define DDR_OPERATION_BASE (DDR_VIRT_BASE | 0x1418)
#define DEV_BUS_PHYS_BASE (KIRKWOOD_REGS_PHYS_BASE | 0x10000)
#define DEV_BUS_VIRT_BASE (KIRKWOOD_REGS_VIRT_BASE | 0x10000)
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