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author | Anson Huang <b20788@freescale.com> | 2014-01-09 16:03:16 +0800 |
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committer | Shawn Guo <shawn.guo@linaro.org> | 2014-03-05 10:35:01 +0800 |
commit | 751f7e999afcef157527f5f6f06529c93f8a4022 (patch) | |
tree | 49dae752f037aa96d2a61ec88ee5179a75c0d86d /arch/arm/mach-imx/cpuidle-imx6sl.c | |
parent | 848db4a0a17aaf97b8ba5b1f754d635ff622670a (diff) | |
download | op-kernel-dev-751f7e999afcef157527f5f6f06529c93f8a4022.zip op-kernel-dev-751f7e999afcef157527f5f6f06529c93f8a4022.tar.gz |
ARM: imx: add cpuidle support for i.mx6sl
Add cpuidle support for i.MX6SL, currently only support
two cpuidle levels(ARM wfi and WAIT mode), and add software
workaround for WAIT mode errata as below:
ERR005311 CCM: After exit from WAIT mode, unwanted interrupt(s) taken
during WAIT mode entry process could cause cache memory
corruption.
Software workaround:
To prevent this issue from occurring, software should ensure that
the ARM to IPG clock ratio is less than 12:5 (that is < 2.4x), before
entering WAIT mode.
Signed-off-by: Anson Huang <b20788@freescale.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
Diffstat (limited to 'arch/arm/mach-imx/cpuidle-imx6sl.c')
-rw-r--r-- | arch/arm/mach-imx/cpuidle-imx6sl.c | 57 |
1 files changed, 57 insertions, 0 deletions
diff --git a/arch/arm/mach-imx/cpuidle-imx6sl.c b/arch/arm/mach-imx/cpuidle-imx6sl.c new file mode 100644 index 0000000..d4b6b81 --- /dev/null +++ b/arch/arm/mach-imx/cpuidle-imx6sl.c @@ -0,0 +1,57 @@ +/* + * Copyright (C) 2014 Freescale Semiconductor, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License version 2 as + * published by the Free Software Foundation. + */ + +#include <linux/cpuidle.h> +#include <linux/module.h> +#include <asm/cpuidle.h> +#include <asm/proc-fns.h> + +#include "common.h" +#include "cpuidle.h" + +static int imx6sl_enter_wait(struct cpuidle_device *dev, + struct cpuidle_driver *drv, int index) +{ + imx6q_set_lpm(WAIT_UNCLOCKED); + /* + * Software workaround for ERR005311, see function + * description for details. + */ + imx6sl_set_wait_clk(true); + cpu_do_idle(); + imx6sl_set_wait_clk(false); + imx6q_set_lpm(WAIT_CLOCKED); + + return index; +} + +static struct cpuidle_driver imx6sl_cpuidle_driver = { + .name = "imx6sl_cpuidle", + .owner = THIS_MODULE, + .states = { + /* WFI */ + ARM_CPUIDLE_WFI_STATE, + /* WAIT */ + { + .exit_latency = 50, + .target_residency = 75, + .flags = CPUIDLE_FLAG_TIME_VALID | + CPUIDLE_FLAG_TIMER_STOP, + .enter = imx6sl_enter_wait, + .name = "WAIT", + .desc = "Clock off", + }, + }, + .state_count = 2, + .safe_state_index = 0, +}; + +int __init imx6sl_cpuidle_init(void) +{ + return cpuidle_register(&imx6sl_cpuidle_driver, NULL); +} |