Revert "ARM: OMAP4: remove dead kconfig option OMAP4_ERRATA_I688"

This reverts commit 606da4826b89b044b51e3a84958b802204cfe4c7.

We actually need this code for proper behaviour of OMAP4, and it needs
fixing a different way other than just removing the code.  Disabling
code which is necessary in the hopes of persuing multiplatform kernels
is a stupid approach.

Acked-by: Tony Lindgren <tony@atomide.com>
Acked-by: Richard Woodruff <r-woodruff2@ti.com>
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>

1 files changed, 69 insertions, 0 deletions

diff --git a/arch/arm/mach-omap2/omap4-common.c b/arch/arm/mach-omap2/omap4-common.c
index 16350eefa66c..7bb116a6f86f 100644
--- a/arch/arm/mach-omap2/omap4-common.c
+++ b/arch/arm/mach-omap2/omap4-common.c
@@ -51,6 +51,75 @@ static void __iomem *twd_base;
 
 #define IRQ_LOCALTIMER		29
 
+#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;
+
+static phys_addr_t paddr;
+static u32 size;
+
+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();
+	}
+}
+EXPORT_SYMBOL(omap_bus_sync);
+
+static int __init omap4_sram_init(void)
+{
+	struct device_node *np;
+	struct gen_pool *sram_pool;
+
+	np = of_find_compatible_node(NULL, NULL, "ti,omap4-mpu");
+	if (!np)
+		pr_warn("%s:Unable to allocate sram needed to handle errata I688\n",
+			__func__);
+	sram_pool = of_get_named_gen_pool(np, "sram", 0);
+	if (!sram_pool)
+		pr_warn("%s:Unable to get sram pool needed to handle errata I688\n",
+			__func__);
+	else
+		sram_sync = (void *)gen_pool_alloc(sram_pool, PAGE_SIZE);
+
+	return 0;
+}
+omap_arch_initcall(omap4_sram_init);
+
+/* Steal one page physical memory for barrier implementation */
+int __init omap_barrier_reserve_memblock(void)
+{
+
+	size = ALIGN(PAGE_SIZE, SZ_1M);
+	paddr = arm_memblock_steal(size, SZ_1M);
+
+	return 0;
+}
+
+void __init omap_barriers_init(void)
+{
+	struct map_desc dram_io_desc[1];
+
+	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_RW_SO;
+	iotable_init(dram_io_desc, ARRAY_SIZE(dram_io_desc));
+	dram_sync = (void __iomem *) dram_io_desc[0].virtual;
+
+	pr_info("OMAP4: Map 0x%08llx to 0x%08lx for dram barrier\n",
+		(long long) paddr, dram_io_desc[0].virtual);
+
+}
+#else
+void __init omap_barriers_init(void)
+{}
+#endif
+
 void gic_dist_disable(void)
 {
 	if (gic_dist_base_addr)