linux/arch/arm/mach-omap2/omap4-common.c
Santosh Shilimkar 137d105d50 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>
2011-12-08 11:29:01 -08:00

205 lines
4.6 KiB
C

/*
* OMAP4 specific common source file.
*
* Copyright (C) 2010 Texas Instruments, Inc.
* Author:
* 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/kernel.h>
#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>
#include "common.h"
#include "omap4-sar-layout.h"
#ifdef CONFIG_CACHE_L2X0
static void __iomem *l2cache_base;
#endif
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;
void __iomem *gic_dist_base_addr;
/* Static mapping, never released */
gic_dist_base_addr = ioremap(OMAP44XX_GIC_DIST_BASE, SZ_4K);
BUG_ON(!gic_dist_base_addr);
/* Static mapping, never released */
omap_irq_base = ioremap(OMAP44XX_GIC_CPU_BASE, SZ_512);
BUG_ON(!omap_irq_base);
omap_wakeupgen_init();
gic_init(0, 29, gic_dist_base_addr, omap_irq_base);
}
#ifdef CONFIG_CACHE_L2X0
void __iomem *omap4_get_l2cache_base(void)
{
return l2cache_base;
}
static void omap4_l2x0_disable(void)
{
/* Disable PL310 L2 Cache controller */
omap_smc1(0x102, 0x0);
}
static void omap4_l2x0_set_debug(unsigned long val)
{
/* Program PL310 L2 Cache controller debug register */
omap_smc1(0x100, val);
}
static int __init omap_l2_cache_init(void)
{
u32 aux_ctrl = 0;
/*
* To avoid code running on other OMAPs in
* multi-omap builds
*/
if (!cpu_is_omap44xx())
return -ENODEV;
/* Static mapping, never released */
l2cache_base = ioremap(OMAP44XX_L2CACHE_BASE, SZ_4K);
if (WARN_ON(!l2cache_base))
return -ENOMEM;
/*
* 16-way associativity, parity disabled
* Way size - 32KB (es1.0)
* Way size - 64KB (es2.0 +)
*/
aux_ctrl = ((1 << L2X0_AUX_CTRL_ASSOCIATIVITY_SHIFT) |
(0x1 << 25) |
(0x1 << L2X0_AUX_CTRL_NS_LOCKDOWN_SHIFT) |
(0x1 << L2X0_AUX_CTRL_NS_INT_CTRL_SHIFT));
if (omap_rev() == OMAP4430_REV_ES1_0) {
aux_ctrl |= 0x2 << L2X0_AUX_CTRL_WAY_SIZE_SHIFT;
} else {
aux_ctrl |= ((0x3 << L2X0_AUX_CTRL_WAY_SIZE_SHIFT) |
(1 << L2X0_AUX_CTRL_SHARE_OVERRIDE_SHIFT) |
(1 << L2X0_AUX_CTRL_DATA_PREFETCH_SHIFT) |
(1 << L2X0_AUX_CTRL_INSTR_PREFETCH_SHIFT) |
(1 << L2X0_AUX_CTRL_EARLY_BRESP_SHIFT));
}
if (omap_rev() != OMAP4430_REV_ES1_0)
omap_smc1(0x109, aux_ctrl);
/* Enable PL310 L2 Cache controller */
omap_smc1(0x102, 0x1);
l2x0_init(l2cache_base, aux_ctrl, L2X0_AUX_CTRL_MASK);
/*
* Override default outer_cache.disable with a OMAP4
* specific one
*/
outer_cache.disable = omap4_l2x0_disable;
outer_cache.set_debug = omap4_l2x0_set_debug;
return 0;
}
early_initcall(omap_l2_cache_init);
#endif
void __iomem *omap4_get_sar_ram_base(void)
{
return sar_ram_base;
}
/*
* SAR RAM used to save and restore the HW
* context in low power modes
*/
static int __init omap4_sar_ram_init(void)
{
/*
* To avoid code running on other OMAPs in
* multi-omap builds
*/
if (!cpu_is_omap44xx())
return -ENOMEM;
/* Static mapping, never released */
sar_ram_base = ioremap(OMAP44XX_SAR_RAM_BASE, SZ_16K);
if (WARN_ON(!sar_ram_base))
return -ENOMEM;
return 0;
}
early_initcall(omap4_sar_ram_init);