From 751f7e999afcef157527f5f6f06529c93f8a4022 Mon Sep 17 00:00:00 2001 From: Anson Huang Date: Thu, 9 Jan 2014 16:03:16 +0800 Subject: 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 Signed-off-by: Shawn Guo --- arch/arm/mach-imx/Makefile | 1 + arch/arm/mach-imx/clk-imx6sl.c | 26 +++++++++++++++++ arch/arm/mach-imx/common.h | 1 + arch/arm/mach-imx/cpuidle-imx6sl.c | 57 ++++++++++++++++++++++++++++++++++++++ arch/arm/mach-imx/cpuidle.h | 5 ++++ arch/arm/mach-imx/mach-imx6sl.c | 3 ++ 6 files changed, 93 insertions(+) create mode 100644 arch/arm/mach-imx/cpuidle-imx6sl.c (limited to 'arch') diff --git a/arch/arm/mach-imx/Makefile b/arch/arm/mach-imx/Makefile index ec419649320f..21114a9a2ae7 100644 --- a/arch/arm/mach-imx/Makefile +++ b/arch/arm/mach-imx/Makefile @@ -30,6 +30,7 @@ obj-$(CONFIG_MXC_DEBUG_BOARD) += 3ds_debugboard.o ifeq ($(CONFIG_CPU_IDLE),y) obj-$(CONFIG_SOC_IMX5) += cpuidle-imx5.o obj-$(CONFIG_SOC_IMX6Q) += cpuidle-imx6q.o +obj-$(CONFIG_SOC_IMX6SL) += cpuidle-imx6sl.o endif ifdef CONFIG_SND_IMX_SOC diff --git a/arch/arm/mach-imx/clk-imx6sl.c b/arch/arm/mach-imx/clk-imx6sl.c index c5f17c2d4951..6f21a1333fe4 100644 --- a/arch/arm/mach-imx/clk-imx6sl.c +++ b/arch/arm/mach-imx/clk-imx6sl.c @@ -66,6 +66,32 @@ static struct clk_div_table video_div_table[] = { static struct clk *clks[IMX6SL_CLK_END]; static struct clk_onecell_data clk_data; +/* + * 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. + * + * This function will set the ARM clk to max value within the 12:5 limit. + */ +void imx6sl_set_wait_clk(bool enter) +{ + static unsigned long saved_arm_rate; + + if (enter) { + unsigned long ipg_rate = clk_get_rate(clks[IMX6SL_CLK_IPG]); + unsigned long max_arm_wait_rate = (12 * ipg_rate) / 5; + saved_arm_rate = clk_get_rate(clks[IMX6SL_CLK_ARM]); + clk_set_rate(clks[IMX6SL_CLK_ARM], max_arm_wait_rate); + } else { + clk_set_rate(clks[IMX6SL_CLK_ARM], saved_arm_rate); + } +} + static void __init imx6sl_clocks_init(struct device_node *ccm_node) { struct device_node *np; diff --git a/arch/arm/mach-imx/common.h b/arch/arm/mach-imx/common.h index cdbddfa2a42f..b909b689619b 100644 --- a/arch/arm/mach-imx/common.h +++ b/arch/arm/mach-imx/common.h @@ -140,6 +140,7 @@ void imx_anatop_pre_suspend(void); void imx_anatop_post_resume(void); int imx6q_set_lpm(enum mxc_cpu_pwr_mode mode); void imx6q_set_int_mem_clk_lpm(void); +void imx6sl_set_wait_clk(bool enter); void imx_cpu_die(unsigned int cpu); int imx_cpu_kill(unsigned int cpu); diff --git a/arch/arm/mach-imx/cpuidle-imx6sl.c b/arch/arm/mach-imx/cpuidle-imx6sl.c new file mode 100644 index 000000000000..d4b6b8171fa9 --- /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 +#include +#include +#include + +#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); +} diff --git a/arch/arm/mach-imx/cpuidle.h b/arch/arm/mach-imx/cpuidle.h index 786f98ecc145..24e33670417c 100644 --- a/arch/arm/mach-imx/cpuidle.h +++ b/arch/arm/mach-imx/cpuidle.h @@ -13,6 +13,7 @@ #ifdef CONFIG_CPU_IDLE extern int imx5_cpuidle_init(void); extern int imx6q_cpuidle_init(void); +extern int imx6sl_cpuidle_init(void); #else static inline int imx5_cpuidle_init(void) { @@ -22,4 +23,8 @@ static inline int imx6q_cpuidle_init(void) { return 0; } +static inline int imx6sl_cpuidle_init(void) +{ + return 0; +} #endif diff --git a/arch/arm/mach-imx/mach-imx6sl.c b/arch/arm/mach-imx/mach-imx6sl.c index 0f4fd4c0ab8e..a26fdb2b1a6f 100644 --- a/arch/arm/mach-imx/mach-imx6sl.c +++ b/arch/arm/mach-imx/mach-imx6sl.c @@ -17,6 +17,7 @@ #include #include "common.h" +#include "cpuidle.h" static void __init imx6sl_fec_init(void) { @@ -39,6 +40,8 @@ static void __init imx6sl_init_late(void) /* imx6sl reuses imx6q cpufreq driver */ if (IS_ENABLED(CONFIG_ARM_IMX6Q_CPUFREQ)) platform_device_register_simple("imx6q-cpufreq", -1, NULL, 0); + + imx6sl_cpuidle_init(); } static void __init imx6sl_init_machine(void) -- cgit v1.2.3