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authorAnson Huang <b20788@freescale.com>2014-01-09 16:03:16 +0800
committerShawn Guo <shawn.guo@linaro.org>2014-03-05 10:35:01 +0800
commit751f7e999afcef157527f5f6f06529c93f8a4022 (patch)
tree49dae752f037aa96d2a61ec88ee5179a75c0d86d /arch/arm/mach-imx/cpuidle-imx6sl.c
parent848db4a0a17aaf97b8ba5b1f754d635ff622670a (diff)
downloadlinux-751f7e999afcef157527f5f6f06529c93f8a4022.tar.bz2
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.c57
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 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 <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);
+}