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Commit e50b6bef authored by Rabeeh Khoury's avatar Rabeeh Khoury Committed by Nicolas Pitre
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[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: default avatarRabeeh Khoury <rabeeh@marvell.com>
Signed-off-by: default avatarNicolas Pitre <nico@marvell.com>
parent a914d430

arch/arm/configs/kirkwood_defconfig

+3 −1
Original line number Diff line number Diff line
@@ -270,7 +270,9 @@ CONFIG_CMDLINE="" 
#

# CPU Power Management

#

# CONFIG_CPU_IDLE is not set

CONFIG_CPU_IDLE=y

CONFIG_CPU_IDLE_GOV_LADDER=y

CONFIG_CPU_IDLE_GOV_MENU=y



#

# Floating point emulation

arch/arm/mach-kirkwood/Makefile

+2 −0
Original line number Diff line number Diff line
@@ -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

arch/arm/mach-kirkwood/cpuidle.c

0 → 100644
+96 −0
Original line number Diff line number Diff line 
/*

 * 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);

arch/arm/mach-kirkwood/include/mach/kirkwood.h

+1 −0
Original line number Diff line number Diff line
@@ -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)