1 files changed, 26 insertions, 0 deletions

diff --git a/arch/mips/sgi-ip22/ip22-mc.c b/arch/mips/sgi-ip22/ip22-mc.c
index 3f35d6367bec..5268ac187bbd 100644
--- a/arch/mips/sgi-ip22/ip22-mc.c
+++ b/arch/mips/sgi-ip22/ip22-mc.c
@@ -208,4 +208,30 @@ void __init sgimc_init(void)
 void __init prom_meminit(void) {}
 void __init prom_free_prom_memory(void)
 {
+#ifdef CONFIG_SGI_IP28
+        u32 mconfig1;
+        unsigned long flags;
+        spinlock_t lock;
+
+        /*
+         * because ARCS accesses memory uncached we wait until ARCS
+         * isn't needed any longer, before we switch from slow to
+         * normal mode
+         */
+        spin_lock_irqsave(&lock, flags);
+        mconfig1 = sgimc->mconfig1;
+        /* map ECC register */
+        sgimc->mconfig1 = (mconfig1 & 0xffff0000) | 0x2060;
+        iob();
+        /* switch to normal mode */
+        *(unsigned long *)PHYS_TO_XKSEG_UNCACHED(0x60000000) = 0;
+        iob();
+        /* reduce WR_COL */
+        sgimc->cmacc = (sgimc->cmacc & ~0xf) | 4;
+        iob();
+        /* restore old config */
+        sgimc->mconfig1 = mconfig1;
+        iob();
+        spin_unlock_irqrestore(&lock, flags);
+#endif
 }