ARM: OMAP5 / DRA7: Introduce workaround for 801819

[cascardo/linux.git] / arch / arm / mach-omap2 / omap-smp.c

diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
index c625cc1..8cd1de9 100644 (file)
--- a/arch/arm/mach-omap2/omap-smp.c
+++ b/arch/arm/mach-omap2/omap-smp.c
@@ -50,6 +50,39 @@ void __iomem *omap4_get_scu_base(void)
        return scu_base;
 }
 
+#ifdef CONFIG_OMAP5_ERRATA_801819
+void omap5_erratum_workaround_801819(void)
+{
+       u32 acr, revidr;
+       u32 acr_mask;
+
+       /* REVIDR[3] indicates erratum fix available on silicon */
+       asm volatile ("mrc p15, 0, %0, c0, c0, 6" : "=r" (revidr));
+       if (revidr & (0x1 << 3))
+               return;
+
+       asm volatile ("mrc p15, 0, %0, c1, c0, 1" : "=r" (acr));
+       /*
+        * BIT(27) - Disables streaming. All write-allocate lines allocate in
+        * the L1 or L2 cache.
+        * BIT(25) - Disables streaming. All write-allocate lines allocate in
+        * the L1 cache.
+        */
+       acr_mask = (0x3 << 25) | (0x3 << 27);
+       /* do we already have it done.. if yes, skip expensive smc */
+       if ((acr & acr_mask) == acr_mask)
+               return;
+
+       acr |= acr_mask;
+       omap_smc1(OMAP5_DRA7_MON_SET_ACR_INDEX, acr);
+
+       pr_debug("%s: ARM erratum workaround 801819 applied on CPU%d\n",
+                __func__, smp_processor_id());
+}
+#else
+static inline void omap5_erratum_workaround_801819(void) { }
+#endif
+
 static void omap4_secondary_init(unsigned int cpu)
 {
        /*
@@ -64,12 +97,15 @@ static void omap4_secondary_init(unsigned int cpu)
                omap_secure_dispatcher(OMAP4_PPA_CPU_ACTRL_SMP_INDEX,
                                                        4, 0, 0, 0, 0, 0);
 
-       /*
-        * Configure the CNTFRQ register for the secondary cpu's which
-        * indicates the frequency of the cpu local timers.
-        */
-       if (soc_is_omap54xx() || soc_is_dra7xx())
+       if (soc_is_omap54xx() || soc_is_dra7xx()) {
+               /*
+                * Configure the CNTFRQ register for the secondary cpu's which
+                * indicates the frequency of the cpu local timers.
+                */
                set_cntfreq();
+               /* Configure ACR to disable streaming WA for 801819 */
+               omap5_erratum_workaround_801819();
+       }
 
        /*
         * Synchronise with the boot thread.
@@ -218,6 +254,8 @@ static void __init omap4_smp_prepare_cpus(unsigned int max_cpus)
 
        if (cpu_is_omap446x())
                startup_addr = omap4460_secondary_startup;
+       if (soc_is_dra74x() || soc_is_omap54xx())
+               omap5_erratum_workaround_801819();
 
        /*
         * Write the address of secondary startup routine into the