+#ifdef CONFIG_OMAP4_ERRATA_I688
+/* Used to implement memory barrier on DRAM path */
+#define OMAP4_DRAM_BARRIER_VA 0xfe600000
+
+void __iomem *dram_sync, *sram_sync;
+
+void omap_bus_sync(void)
+{
+ if (dram_sync && sram_sync) {
+ writel_relaxed(readl_relaxed(dram_sync), dram_sync);
+ writel_relaxed(readl_relaxed(sram_sync), sram_sync);
+ isb();
+ }
+}
+
+static int __init omap_barriers_init(void)
+{
+ struct map_desc dram_io_desc[1];
+ phys_addr_t paddr;
+ u32 size;
+
+ if (!cpu_is_omap44xx())
+ return -ENODEV;
+
+ size = ALIGN(PAGE_SIZE, SZ_1M);
+ paddr = memblock_alloc(size, SZ_1M);
+ if (!paddr) {
+ pr_err("%s: failed to reserve 4 Kbytes\n", __func__);
+ return -ENOMEM;
+ }
+ memblock_free(paddr, size);
+ memblock_remove(paddr, size);
+ dram_io_desc[0].virtual = OMAP4_DRAM_BARRIER_VA;
+ dram_io_desc[0].pfn = __phys_to_pfn(paddr);
+ dram_io_desc[0].length = size;
+ dram_io_desc[0].type = MT_MEMORY_SO;
+ iotable_init(dram_io_desc, ARRAY_SIZE(dram_io_desc));
+ dram_sync = (void __iomem *) dram_io_desc[0].virtual;
+ sram_sync = (void __iomem *) OMAP4_SRAM_VA;
+
+ pr_info("OMAP4: Map 0x%08llx to 0x%08lx for dram barrier\n",
+ (long long) paddr, dram_io_desc[0].virtual);
+
+ return 0;
+}
+core_initcall(omap_barriers_init);
+#endif
+