ARM: imx6: initialize CCM_CLPCR_LPM into RUN mode earlier
Commit 4631960d26da ("ARM: imx6: set initial power mode in pm function")
moves imx6_set_lpm() from clock init function into
imx6_pm_common_init(). This causes a hang when cpuidle support is
enabled. The reason for that is ARM core clock is shut down
unexpectedly by WAIT mode. It happens with the following call stack:
cpuidle_register_governor()
cpuidle_switch_governor()
cpuidle_uninstall_idle_handler()
synchronize_sched()
wait_rcu_gp()
wait_for_completion()
When wait_for_completion() is called as above, all cores are idle/WFI.
Hence, the reset value of CCM_CLPCR_LPM - WAIT mode, will trigger a
hardware shutdown of the ARM core clock.
To fix the regression, we need to ensure that CCM_CLPCR_LPM is
initialized into RUN mode earlier than cpuidle governor registration,
which is a postcore_initcall. This patch creates function
imx6_pm_ccm_init() to map CCM block and initialize CCM_CLPCR_LPM into
RUN mode, and have the function called from machine .init_irq hook,
which should be early enough.
Reported-by: Kevin Hilman <khilman@kernel.org>
Fixes: 8fb76a07e2cb ("ARM: imx6: set initial power mode in pm function")
Tested-by: Kevin Hilman <khilman@linaro.org>
Tested-by: Tyler Baker <tyler.baker@linaro.org>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
diff --git a/arch/arm/mach-imx/pm-imx6.c b/arch/arm/mach-imx/pm-imx6.c
index 27bc80d..b01650d 100644
--- a/arch/arm/mach-imx/pm-imx6.c
+++ b/arch/arm/mach-imx/pm-imx6.c
@@ -89,7 +89,6 @@
struct imx6_pm_socdata {
u32 ddr_type;
- const char *ccm_compat;
const char *mmdc_compat;
const char *src_compat;
const char *iomuxc_compat;
@@ -139,7 +138,6 @@
};
static const struct imx6_pm_socdata imx6q_pm_data __initconst = {
- .ccm_compat = "fsl,imx6q-ccm",
.mmdc_compat = "fsl,imx6q-mmdc",
.src_compat = "fsl,imx6q-src",
.iomuxc_compat = "fsl,imx6q-iomuxc",
@@ -149,7 +147,6 @@
};
static const struct imx6_pm_socdata imx6dl_pm_data __initconst = {
- .ccm_compat = "fsl,imx6q-ccm",
.mmdc_compat = "fsl,imx6q-mmdc",
.src_compat = "fsl,imx6q-src",
.iomuxc_compat = "fsl,imx6dl-iomuxc",
@@ -159,7 +156,6 @@
};
static const struct imx6_pm_socdata imx6sl_pm_data __initconst = {
- .ccm_compat = "fsl,imx6sl-ccm",
.mmdc_compat = "fsl,imx6sl-mmdc",
.src_compat = "fsl,imx6sl-src",
.iomuxc_compat = "fsl,imx6sl-iomuxc",
@@ -169,7 +165,6 @@
};
static const struct imx6_pm_socdata imx6sx_pm_data __initconst = {
- .ccm_compat = "fsl,imx6sx-ccm",
.mmdc_compat = "fsl,imx6sx-mmdc",
.src_compat = "fsl,imx6sx-src",
.iomuxc_compat = "fsl,imx6sx-iomuxc",
@@ -553,16 +548,11 @@
static void __init imx6_pm_common_init(const struct imx6_pm_socdata
*socdata)
{
- struct device_node *np;
struct regmap *gpr;
int ret;
- np = of_find_compatible_node(NULL, NULL, socdata->ccm_compat);
- ccm_base = of_iomap(np, 0);
WARN_ON(!ccm_base);
- imx6_set_lpm(WAIT_CLOCKED);
-
if (IS_ENABLED(CONFIG_SUSPEND)) {
ret = imx6q_suspend_init(socdata);
if (ret)
@@ -583,6 +573,24 @@
IMX6Q_GPR1_GINT);
}
+void __init imx6_pm_ccm_init(const char *ccm_compat)
+{
+ struct device_node *np;
+ u32 val;
+
+ np = of_find_compatible_node(NULL, NULL, ccm_compat);
+ ccm_base = of_iomap(np, 0);
+ BUG_ON(!ccm_base);
+
+ /*
+ * Initialize CCM_CLPCR_LPM into RUN mode to avoid ARM core
+ * clock being shut down unexpectedly by WAIT mode.
+ */
+ val = readl_relaxed(ccm_base + CLPCR);
+ val &= ~BM_CLPCR_LPM;
+ writel_relaxed(val, ccm_base + CLPCR);
+}
+
void __init imx6q_pm_init(void)
{
imx6_pm_common_init(&imx6q_pm_data);