ARM: OMAP4: Fix errata i688 with MPU interconnect barriers.

On OMAP4 SOC, intecronnects has many write buffers in the async bridges
and they need to be drained before CPU enters into standby state.

Patch 'OMAP4: PM: Add CPUX OFF mode support' added CPU PM support
but OMAP errata i688 (Async Bridge Corruption) needs to be taken
care to avoid issues like system freeze, CPU deadlocks, random
crashes with register accesses, synchronisation loss on initiators
operating on both interconnect port simultaneously.

As per the errata, 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.

Thanks to Russell for a tip to conver assembly function to
C fuction there by reducing 40 odd lines of code from the patch.

Signed-off-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Signed-off-by: Richard Woodruff <r-woodruff2@ti.com>
Acked-by: Jean Pihet <j-pihet@ti.com>
Reviewed-by: Kevin Hilman <khilman@ti.com>
Tested-by: Vishwanath BS <vishwanath.bs@ti.com>
Signed-off-by: Kevin Hilman <khilman@ti.com>

Conflicts:

	arch/arm/mach-omap2/omap4-common.c
	arch/arm/mach-omap2/sleep44xx.S

7 files changed, 504 insertions, 1 deletions

diff --git a/arch/arm/mach-omap2/Kconfig b/arch/arm/mach-omap2/Kconfig
index 4f01533083c..5133b797544 100644
--- a/arch/arm/mach-omap2/Kconfig
+++ b/arch/arm/mach-omap2/Kconfig
@@ -355,6 +355,27 @@ 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 00000000000..4fa72c7cc7c
--- /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 3f565dd2ea8..65843390e7f 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 beecfdd56ea..da202aa71c6 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>
 
@@ -29,6 +32,54 @@
 void __iomem *l2cache_base;
 #endif
 
+#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
new file mode 100644
index 00000000000..abd28340049
--- /dev/null
+++ b/arch/arm/mach-omap2/sleep44xx.S
@@ -0,0 +1,379 @@
+/*
+ * OMAP44xx sleep code.
+ *
+ * Copyright (C) 2011 Texas Instruments, Inc.
+ * 	Santosh Shilimkar <santosh.shilimkar@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.
+ */
+
+#include <linux/linkage.h>
+#include <asm/system.h>
+#include <asm/smp_scu.h>
+#include <asm/memory.h>
+#include <asm/hardware/cache-l2x0.h>
+
+#include <plat/omap44xx.h>
+#include <mach/omap-secure.h>
+
+#include "common.h"
+#include "omap4-sar-layout.h"
+
+#if defined(CONFIG_SMP) && defined(CONFIG_PM)
+
+.macro	DO_SMC
+	dsb
+	smc	#0
+	dsb
+.endm
+
+ppa_zero_params:
+	.word		0x0
+
+ppa_por_params:
+	.word		1, 0
+
+/*
+ * =============================
+ * == CPU suspend finisher ==
+ * =============================
+ *
+ * void omap4_finish_suspend(unsigned long cpu_state)
+ *
+ * This function code saves the CPU context and performs the CPU
+ * power down sequence. Calling WFI effectively changes the CPU
+ * power domains states to the desired target power state.
+ *
+ * @cpu_state : contains context save state (r0)
+ *	0 - No context lost
+ * 	1 - CPUx L1 and logic lost: MPUSS CSWR
+ * 	2 - CPUx L1 and logic lost + GIC lost: MPUSS OSWR
+ *	3 - CPUx L1 and logic lost + GIC + L2 lost: MPUSS OFF
+ * @return: This function never returns for CPU OFF and DORMANT power states.
+ * Post WFI, CPU transitions to DORMANT or OFF power state and on wake-up
+ * from this follows a full CPU reset path via ROM code to CPU restore code.
+ * The restore function pointer is stored at CPUx_WAKEUP_NS_PA_ADDR_OFFSET.
+ * It returns to the caller for CPU INACTIVE and ON power states or in case
+ * CPU failed to transition to targeted OFF/DORMANT state.
+ */
+ENTRY(omap4_finish_suspend)
+	stmfd	sp!, {lr}
+	cmp	r0, #0x0
+	beq	do_WFI				@ No lowpower state, jump to WFI
+
+	/*
+	 * Flush all data from the L1 data cache before disabling
+	 * SCTLR.C bit.
+	 */
+	bl	omap4_get_sar_ram_base
+	ldr	r9, [r0, #OMAP_TYPE_OFFSET]
+	cmp	r9, #0x1			@ Check for HS device
+	bne	skip_secure_l1_clean
+	mov	r0, #SCU_PM_NORMAL
+	mov	r1, #0xFF			@ clean seucre L1
+	stmfd   r13!, {r4-r12, r14}
+	ldr	r12, =OMAP4_MON_SCU_PWR_INDEX
+	DO_SMC
+	ldmfd   r13!, {r4-r12, r14}
+skip_secure_l1_clean:
+	bl	v7_flush_dcache_all
+
+	/*
+	 * Clear the SCTLR.C bit to prevent further data cache
+	 * allocation. Clearing SCTLR.C would make all the data accesses
+	 * strongly ordered and would not hit the cache.
+	 */
+	mrc	p15, 0, r0, c1, c0, 0
+	bic	r0, r0, #(1 << 2)		@ Disable the C bit
+	mcr	p15, 0, r0, c1, c0, 0
+	isb
+
+	/*
+	 * Invalidate L1 data cache. Even though only invalidate is
+	 * necessary exported flush API is used here. Doing clean
+	 * on already clean cache would be almost NOP.
+	 */
+	bl	v7_flush_dcache_all
+
+	/*
+	 * Switch the CPU from Symmetric Multiprocessing (SMP) mode
+	 * to AsymmetricMultiprocessing (AMP) mode by programming
+	 * the SCU power status to DORMANT or OFF mode.
+	 * This enables the CPU to be taken out of coherency by
+	 * preventing the CPU from receiving cache, TLB, or BTB
+	 * maintenance operations broadcast by other CPUs in the cluster.
+	 */
+	bl	omap4_get_sar_ram_base
+	mov	r8, r0
+	ldr	r9, [r8, #OMAP_TYPE_OFFSET]
+	cmp	r9, #0x1			@ Check for HS device
+	bne	scu_gp_set
+	mrc	p15, 0, r0, c0, c0, 5		@ Read MPIDR
+	ands	r0, r0, #0x0f
+	ldreq	r0, [r8, #SCU_OFFSET0]
+	ldrne	r0, [r8, #SCU_OFFSET1]
+	mov	r1, #0x00
+	stmfd   r13!, {r4-r12, r14}
+	ldr	r12, =OMAP4_MON_SCU_PWR_INDEX
+	DO_SMC
+	ldmfd   r13!, {r4-r12, r14}
+	b	skip_scu_gp_set
+scu_gp_set:
+	mrc	p15, 0, r0, c0, c0, 5		@ Read MPIDR
+	ands	r0, r0, #0x0f
+	ldreq	r1, [r8, #SCU_OFFSET0]
+	ldrne	r1, [r8, #SCU_OFFSET1]
+	bl	omap4_get_scu_base
+	bl	scu_power_mode
+skip_scu_gp_set:
+	mrc	p15, 0, r0, c1, c1, 2		@ Read NSACR data
+	tst	r0, #(1 << 18)
+	mrcne	p15, 0, r0, c1, c0, 1
+	bicne	r0, r0, #(1 << 6)		@ Disable SMP bit
+	mcrne	p15, 0, r0, c1, c0, 1
+	isb
+	dsb
+#ifdef CONFIG_CACHE_L2X0
+	/*
+	 * Clean and invalidate the L2 cache.
+	 * Common cache-l2x0.c functions can't be used here since it
+	 * uses spinlocks. We are out of coherency here with data cache
+	 * disabled. The spinlock implementation uses exclusive load/store
+	 * instruction which can fail without data cache being enabled.
+	 * OMAP4 hardware doesn't support exclusive monitor which can
+	 * overcome exclusive access issue. Because of this, CPU can
+	 * lead to deadlock.
+	 */
+	bl	omap4_get_sar_ram_base
+	mov	r8, r0
+	mrc	p15, 0, r5, c0, c0, 5		@ Read MPIDR
+	ands	r5, r5, #0x0f
+	ldreq	r0, [r8, #L2X0_SAVE_OFFSET0]	@ Retrieve L2 state from SAR
+	ldrne	r0, [r8, #L2X0_SAVE_OFFSET1]	@ memory.
+	cmp	r0, #3
+	bne	do_WFI
+#ifdef CONFIG_PL310_ERRATA_727915
+	mov	r0, #0x03
+	mov	r12, #OMAP4_MON_L2X0_DBG_CTRL_INDEX
+	DO_SMC
+#endif
+	bl	omap4_get_l2cache_base
+	mov	r2, r0
+	ldr	r0, =0xffff
+	str	r0, [r2, #L2X0_CLEAN_INV_WAY]
+wait:
+	ldr	r0, [r2, #L2X0_CLEAN_INV_WAY]
+	ldr	r1, =0xffff
+	ands	r0, r0, r1
+	bne	wait
+#ifdef CONFIG_PL310_ERRATA_727915
+	mov	r0, #0x00
+	mov	r12, #OMAP4_MON_L2X0_DBG_CTRL_INDEX
+	DO_SMC
+#endif
+l2x_sync:
+	bl	omap4_get_l2cache_base
+	mov	r2, r0
+	mov	r0, #0x0
+	str	r0, [r2, #L2X0_CACHE_SYNC]
+sync:
+	ldr	r0, [r2, #L2X0_CACHE_SYNC]
+	ands	r0, r0, #0x1
+	bne	sync
+#endif
+
+do_WFI:
+	bl	omap_do_wfi
+
+	/*
+	 * CPU is here when it failed to enter OFF/DORMANT or
+	 * no low power state was attempted.
+	 */
+	mrc	p15, 0, r0, c1, c0, 0
+	tst	r0, #(1 << 2)			@ Check C bit enabled?
+	orreq	r0, r0, #(1 << 2)		@ Enable the C bit
+	mcreq	p15, 0, r0, c1, c0, 0
+	isb
+
+	/*
+	 * Ensure the CPU power state is set to NORMAL in
+	 * SCU power state so that CPU is back in coherency.
+	 * In non-coherent mode CPU can lock-up and lead to
+	 * system deadlock.
+	 */
+	mrc	p15, 0, r0, c1, c0, 1
+	tst	r0, #(1 << 6)			@ Check SMP bit enabled?
+	orreq	r0, r0, #(1 << 6)
+	mcreq	p15, 0, r0, c1, c0, 1
+	isb
+	bl	omap4_get_sar_ram_base
+	mov	r8, r0
+	ldr	r9, [r8, #OMAP_TYPE_OFFSET]
+	cmp	r9, #0x1			@ Check for HS device
+	bne	scu_gp_clear
+	mov	r0, #SCU_PM_NORMAL
+	mov	r1, #0x00
+	stmfd   r13!, {r4-r12, r14}
+	ldr	r12, =OMAP4_MON_SCU_PWR_INDEX
+	DO_SMC
+	ldmfd   r13!, {r4-r12, r14}
+	b	skip_scu_gp_clear
+scu_gp_clear:
+	bl	omap4_get_scu_base
+	mov	r1, #SCU_PM_NORMAL
+	bl	scu_power_mode
+skip_scu_gp_clear:
+	isb
+	dsb
+	ldmfd	sp!, {pc}
+ENDPROC(omap4_finish_suspend)
+
+/*
+ * ============================
+ * == CPU resume entry point ==
+ * ============================
+ *
+ * void omap4_cpu_resume(void)
+ *
+ * ROM code jumps to this function while waking up from CPU
+ * OFF or DORMANT state. Physical address of the function is
+ * stored in the SAR RAM while entering to OFF or DORMANT mode.
+ * The restore function pointer is stored at CPUx_WAKEUP_NS_PA_ADDR_OFFSET.
+ */
+ENTRY(omap4_cpu_resume)
+	/*
+	 * Configure ACTRL and enable NS SMP bit access on CPU1 on HS device.
+	 * OMAP44XX EMU/HS devices - CPU0 SMP bit access is enabled in PPA
+	 * init and for CPU1, a secure PPA API provided. CPU0 must be ON
+	 * while executing NS_SMP API on CPU1 and PPA version must be 1.4.0+.
+	 * OMAP443X GP devices- SMP bit isn't accessible.
+	 * OMAP446X GP devices - SMP bit access is enabled on both CPUs.
+	 */
+	ldr	r8, =OMAP44XX_SAR_RAM_BASE
+	ldr	r9, [r8, #OMAP_TYPE_OFFSET]
+	cmp	r9, #0x1			@ Skip if GP device
+	bne	skip_ns_smp_enable
+	mrc     p15, 0, r0, c0, c0, 5
+	ands    r0, r0, #0x0f
+	beq	skip_ns_smp_enable
+ppa_actrl_retry:
+	mov     r0, #OMAP4_PPA_CPU_ACTRL_SMP_INDEX
+	adr	r3, ppa_zero_params		@ Pointer to parameters
+	mov	r1, #0x0			@ Process ID
+	mov	r2, #0x4			@ Flag
+	mov	r6, #0xff
+	mov	r12, #0x00			@ Secure Service ID
+	DO_SMC
+	cmp	r0, #0x0			@ API returns 0 on success.
+	beq	enable_smp_bit
+	b	ppa_actrl_retry
+enable_smp_bit:
+	mrc	p15, 0, r0, c1, c0, 1
+	tst	r0, #(1 << 6)			@ Check SMP bit enabled?
+	orreq	r0, r0, #(1 << 6)
+	mcreq	p15, 0, r0, c1, c0, 1
+	isb
+skip_ns_smp_enable:
+#ifdef CONFIG_CACHE_L2X0
+	/*
+	 * Restore the L2 AUXCTRL and enable the L2 cache.
+	 * OMAP4_MON_L2X0_AUXCTRL_INDEX =  Program the L2X0 AUXCTRL
+	 * OMAP4_MON_L2X0_CTRL_INDEX =  Enable the L2 using L2X0 CTRL
+	 * register r0 contains value to be programmed.
+	 * L2 cache is already invalidate by ROM code as part
+	 * of MPUSS OFF wakeup path.
+	 */
+	ldr	r2, =OMAP44XX_L2CACHE_BASE
+	ldr	r0, [r2, #L2X0_CTRL]
+	and	r0, #0x0f
+	cmp	r0, #1
+	beq	skip_l2en			@ Skip if already enabled
+	ldr	r3, =OMAP44XX_SAR_RAM_BASE
+	ldr	r1, [r3, #OMAP_TYPE_OFFSET]
+	cmp	r1, #0x1			@ Check for HS device
+	bne     set_gp_por
+	ldr     r0, =OMAP4_PPA_L2_POR_INDEX
+	ldr     r1, =OMAP44XX_SAR_RAM_BASE
+	ldr     r4, [r1, #L2X0_PREFETCH_CTRL_OFFSET]
+	adr     r3, ppa_por_params
+	str     r4, [r3, #0x04]
+	mov	r1, #0x0			@ Process ID
+	mov	r2, #0x4			@ Flag
+	mov	r6, #0xff
+	mov	r12, #0x00			@ Secure Service ID
+	DO_SMC
+	b	set_aux_ctrl
+set_gp_por:
+	ldr     r1, =OMAP44XX_SAR_RAM_BASE
+	ldr     r0, [r1, #L2X0_PREFETCH_CTRL_OFFSET]
+	ldr	r12, =OMAP4_MON_L2X0_PREFETCH_INDEX	@ Setup L2 PREFETCH
+	DO_SMC
+set_aux_ctrl:
+	ldr     r1, =OMAP44XX_SAR_RAM_BASE
+	ldr	r0, [r1, #L2X0_AUXCTRL_OFFSET]
+	ldr	r12, =OMAP4_MON_L2X0_AUXCTRL_INDEX	@ Setup L2 AUXCTRL
+	DO_SMC
+	mov	r0, #0x1
+	ldr	r12, =OMAP4_MON_L2X0_CTRL_INDEX		@ Enable L2 cache
+	DO_SMC
+skip_l2en:
+#endif
+
+	b	cpu_resume			@ Jump to generic resume
+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
+	 * CP15 register changes have been committed.
+	 */
+	isb
+
+	/*
+	 * Execute a barrier instruction to ensure that all cache,
+	 * TLB and branch predictor maintenance operations issued
+	 * by any CPU in the cluster have completed.
+	 */
+	dsb
+	dmb
+
+	/*
+	 * Execute a WFI instruction and wait until the
+	 * STANDBYWFI output is asserted to indicate that the
+	 * CPU is in idle and low power state. CPU can specualatively
+	 * prefetch the instructions so add NOPs after WFI. Sixteen
+	 * NOPs as per Cortex-A9 pipeline.
+	 */
+	wfi					@ Wait For Interrupt
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+	nop
+
+	ldmfd	sp!, {pc}
+ENDPROC(omap_do_wfi)
diff --git a/arch/arm/plat-omap/include/plat/sram.h b/arch/arm/plat-omap/include/plat/sram.h
index f500fc34d06..75aa1b2bef5 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 8b28664d1c6..ad6a71a00ce 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