7 files changed, 133 insertions, 1 deletions

diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index b6625130831d..50f43942c1aa 100644
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -353,6 +353,27 @@ config OMAP3_SDRC_AC_TIMING
           wish to say no.  Selecting yes without understanding what is
           going on could result in system crashes;
 
+config OMAP4_ERRATA_I688
+        bool "OMAP4 errata: Async Bridge Corruption"
+        depends on ARCH_OMAP4
+        select ARCH_HAS_BARRIERS
+        help
+          If a data is stalled inside asynchronous bridge because of back
+          pressure, it may be accepted multiple times, creating pointer
+          misalignment that will corrupt next transfers on that data path
+          until next reset of the system (No recovery procedure once the
+          issue is hit, the path remains consistently broken). Async bridge
+          can be found on path between MPU to EMIF and MPU to L3 interconnect.
+          This situation can happen only when the idle is initiated by a
+          Master Request Disconnection (which is trigged by software when
+          executing WFI on CPU).
+          The work-around for this errata needs all the initiators connected
+          through async bridge must ensure that data path is properly drained
+          before issuing WFI. This condition will be met if one Strongly ordered
+          access is performed to the target right before executing the WFI.
+          In MPU case, L3 T2ASYNC FIFO and DDR T2ASYNC FIFO needs to be drained.
+          IO barrier ensure that there is no synchronisation loss on initiators
+          operating on both interconnect port simultaneously.
 endmenu
 
 endif
diff --git a/arch/arm/mach-omap2/include/mach/barriers.h b/arch/arm/mach-omap2/include/mach/barriers.h
new file mode 100644
index 000000000000..4fa72c7cc7cd
--- /dev/null
+++ b/arch/arm/mach-omap2/include/mach/barriers.h
@@ -0,0 +1,31 @@
+/*
+ * OMAP memory barrier header.
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ *  Santosh Shilimkar <santosh.shilimkar@ti.com>
+ *  Richard Woodruff <r-woodruff2@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ */
+
+#ifndef __MACH_BARRIERS_H
+#define __MACH_BARRIERS_H
+
+extern void omap_bus_sync(void);
+
+#define rmb()           dsb()
+#define wmb()           do { dsb(); outer_sync(); omap_bus_sync(); } while (0)
+#define mb()            wmb()
+
+#endif  /* __MACH_BARRIERS_H */
diff --git a/arch/arm/mach-omap2/io.c b/arch/arm/mach-omap2/io.c
index 3f565dd2ea8d..65843390e7f0 100644
--- a/arch/arm/mach-omap2/io.c
+++ b/arch/arm/mach-omap2/io.c
@@ -237,6 +237,15 @@ static struct map_desc omap44xx_io_desc[] __initdata = {
                 .length         = L4_EMU_44XX_SIZE,
                 .type           = MT_DEVICE,
         },
+#ifdef CONFIG_OMAP4_ERRATA_I688
+        {
+                .virtual        = OMAP4_SRAM_VA,
+                .pfn            = __phys_to_pfn(OMAP4_SRAM_PA),
+                .length         = PAGE_SIZE,
+                .type           = MT_MEMORY_SO,
+        },
+#endif
+
 };
 #endif
 
diff --git a/arch/arm/mach-omap2/omap4-common.c b/arch/arm/mach-omap2/omap4-common.c
index 1b93d31fe8e9..bc16c818c6b7 100644
--- a/arch/arm/mach-omap2/omap4-common.c
+++ b/arch/arm/mach-omap2/omap4-common.c
@@ -15,11 +15,14 @@
 #include <linux/init.h>
 #include <linux/io.h>
 #include <linux/platform_device.h>
+#include <linux/memblock.h>
 
 #include <asm/hardware/gic.h>
 #include <asm/hardware/cache-l2x0.h>
+#include <asm/mach/map.h>
 
 #include <plat/irqs.h>
+#include <plat/sram.h>
 
 #include <mach/hardware.h>
 #include <mach/omap-wakeupgen.h>
@@ -33,6 +36,54 @@ static void __iomem *l2cache_base;
 
 static void __iomem *sar_ram_base;
 
+#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
+
 void __init gic_init_irq(void)
 {
         void __iomem *omap_irq_base;
diff --git a/arch/arm/mach-omap2/sleep44xx.S b/arch/arm/mach-omap2/sleep44xx.S
index 3154b63def35..abd283400490 100644
--- a/arch/arm/mach-omap2/sleep44xx.S
+++ b/arch/arm/mach-omap2/sleep44xx.S
@@ -325,8 +325,16 @@ skip_l2en:
 ENDPROC(omap4_cpu_resume)
 #endif
 
+#ifndef CONFIG_OMAP4_ERRATA_I688
+ENTRY(omap_bus_sync)
+        mov     pc, lr
+ENDPROC(omap_bus_sync)
+#endif
+
 ENTRY(omap_do_wfi)
         stmfd   sp!, {lr}
+        /* Drain interconnect write buffers. */
+        bl omap_bus_sync
 
         /*
          * Execute an ISB instruction to ensure that all of the
diff --git a/arch/arm/plat-omap/include/plat/sram.h b/arch/arm/plat-omap/include/plat/sram.h
index f500fc34d065..75aa1b2bef51 100644
--- a/arch/arm/plat-omap/include/plat/sram.h
+++ b/arch/arm/plat-omap/include/plat/sram.h
@@ -95,6 +95,10 @@ static inline void omap_push_sram_idle(void) {}
  */
 #define OMAP2_SRAM_PA           0x40200000
 #define OMAP3_SRAM_PA           0x40200000
+#ifdef CONFIG_OMAP4_ERRATA_I688
+#define OMAP4_SRAM_PA           0x40304000
+#define OMAP4_SRAM_VA           0xfe404000
+#else
 #define OMAP4_SRAM_PA           0x40300000
-
+#endif
 #endif
diff --git a/arch/arm/plat-omap/sram.c b/arch/arm/plat-omap/sram.c
index 8b28664d1c62..ad6a71a00cef 100644
--- a/arch/arm/plat-omap/sram.c
+++ b/arch/arm/plat-omap/sram.c
@@ -40,7 +40,11 @@
 #define OMAP1_SRAM_PA           0x20000000
 #define OMAP2_SRAM_PUB_PA       (OMAP2_SRAM_PA + 0xf800)
 #define OMAP3_SRAM_PUB_PA       (OMAP3_SRAM_PA + 0x8000)
+#ifdef CONFIG_OMAP4_ERRATA_I688
+#define OMAP4_SRAM_PUB_PA       OMAP4_SRAM_PA
+#else
 #define OMAP4_SRAM_PUB_PA       (OMAP4_SRAM_PA + 0x4000)
+#endif
 
 #if defined(CONFIG_ARCH_OMAP2PLUS)
 #define SRAM_BOOTLOADER_SZ      0x00
@@ -163,6 +167,10 @@ static void __init omap_map_sram(void)
         if (omap_sram_size == 0)
                 return;
 
+#ifdef CONFIG_OMAP4_ERRATA_I688
+                omap_sram_start += PAGE_SIZE;
+                omap_sram_size -= SZ_16K;
+#endif
         if (cpu_is_omap34xx()) {
                 /*
                  * SRAM must be marked as non-cached on OMAP3 since the