From: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
With EMIF clock-domain put under hardware supervised control, memory
corruption and untraceable crashes are observed on OMAP5. Further
investigation revealed that there is a weakness in the PRCM on this
specific dynamic depedency.
The recommendation is to set MPUSS static dependency towards EMIF
clock-domain to avoid issues. This recommendation holds good for DRA7
family of devices as well.
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@xxxxxx>
[rnayak@xxxxxx: DRA7]
Signed-off-by: Rajendra Nayak <rnayak@xxxxxx>
[nm@xxxxxx: conflict resolution, dra7]
Signed-off-by: Nishanth Menon <nm@xxxxxx>
---
arch/arm/mach-omap2/pm44xx.c | 36 +++++++++++++++++++++++++++++++++---
1 file changed, 33 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mach-omap2/pm44xx.c b/arch/arm/mach-omap2/pm44xx.c
index 0dda6cf..b6f243d 100644
--- a/arch/arm/mach-omap2/pm44xx.c
+++ b/arch/arm/mach-omap2/pm44xx.c
@@ -203,6 +203,32 @@ static inline int omap4_init_static_deps(void)
}
/**
+ * omap5_dra7_init_static_deps - Init static clkdm dependencies on OMAP5 and
+ * DRA7
+ *
+ * The dynamic dependency between MPUSS -> EMIF is broken and has
+ * not worked as expected. The hardware recommendation is to
+ * enable static dependencies for these to avoid system
+ * lock ups or random crashes.
+ */
+static inline int omap5_dra7_init_static_deps(void)
+{
+ struct clockdomain *mpuss_clkdm, *emif_clkdm;
+ int ret;
+
+ mpuss_clkdm = clkdm_lookup("mpu_clkdm");
+ emif_clkdm = clkdm_lookup("emif_clkdm");
+ if (!mpuss_clkdm || !emif_clkdm)
+ return -EINVAL;
+
+ ret = clkdm_add_wkdep(mpuss_clkdm, emif_clkdm);
+ if (ret)
+ pr_err("Failed to add MPUSS -> EMIF wakeup dependency\n");
+
+ return ret;
+}
+
+/**
* omap4_pm_init_early - Does early initialization necessary for OMAP4+ devices
*
* Initializes basic stuff for power management functionality.
@@ -239,10 +265,14 @@ int __init omap4_pm_init(void)
goto err2;
}
- if (cpu_is_omap44xx()) {
+ if (cpu_is_omap44xx())
ret = omap4_init_static_deps();
- if (ret)
- goto err2;
+ else if (soc_is_omap54xx() || soc_is_dra7xx())
+ ret = omap5_dra7_init_static_deps();
+
+ if (ret) {
+ pr_err("Failed to initialise static dependencies.\n");
+ goto err2;
}
ret = omap4_mpuss_init();
--
1.7.9.5
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