linux/arch/arm/mach-ux500/cpu.c
Barry Song fb0225871e ARM: mach-ux500: add explicit cpu_relax() for busy wait loop
using cpu_relax in busy loops is a well-known idiom in the kernel. It's more
for documentation purposes than technically needed here.

Cc: Jamie Iles <jamie@jamieiles.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Barry Song <Baohua.Song@csr.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
2011-08-30 09:22:54 +02:00

149 lines
3.5 KiB
C

/*
* Copyright (C) ST-Ericsson SA 2010
*
* Author: Rabin Vincent <rabin.vincent@stericsson.com> for ST-Ericsson
* License terms: GNU General Public License (GPL) version 2
*/
#include <linux/platform_device.h>
#include <linux/io.h>
#include <linux/clk.h>
#include <linux/mfd/db8500-prcmu.h>
#include <linux/mfd/db5500-prcmu.h>
#include <asm/cacheflush.h>
#include <asm/hardware/cache-l2x0.h>
#include <asm/hardware/gic.h>
#include <asm/mach/map.h>
#include <asm/localtimer.h>
#include <plat/mtu.h>
#include <mach/hardware.h>
#include <mach/setup.h>
#include <mach/devices.h>
#include "clock.h"
void __iomem *_PRCMU_BASE;
#ifdef CONFIG_CACHE_L2X0
static void __iomem *l2x0_base;
#endif
void __init ux500_init_irq(void)
{
void __iomem *dist_base;
void __iomem *cpu_base;
if (cpu_is_u5500()) {
dist_base = __io_address(U5500_GIC_DIST_BASE);
cpu_base = __io_address(U5500_GIC_CPU_BASE);
} else if (cpu_is_u8500()) {
dist_base = __io_address(U8500_GIC_DIST_BASE);
cpu_base = __io_address(U8500_GIC_CPU_BASE);
} else
ux500_unknown_soc();
gic_init(0, 29, dist_base, cpu_base);
/*
* Init clocks here so that they are available for system timer
* initialization.
*/
if (cpu_is_u5500())
db5500_prcmu_early_init();
if (cpu_is_u8500())
prcmu_early_init();
clk_init();
}
#ifdef CONFIG_CACHE_L2X0
static inline void ux500_cache_wait(void __iomem *reg, unsigned long mask)
{
/* wait for the operation to complete */
while (readl_relaxed(reg) & mask)
cpu_relax();
}
static inline void ux500_cache_sync(void)
{
void __iomem *base = l2x0_base;
writel_relaxed(0, base + L2X0_CACHE_SYNC);
ux500_cache_wait(base + L2X0_CACHE_SYNC, 1);
}
/*
* The L2 cache cannot be turned off in the non-secure world.
* Dummy until a secure service is in place.
*/
static void ux500_l2x0_disable(void)
{
}
/*
* This is only called when doing a kexec, just after turning off the L2
* and L1 cache, and it is surrounded by a spinlock in the generic version.
* However, we're not really turning off the L2 cache right now and the
* PL310 does not support exclusive accesses (used to implement the spinlock).
* So, the invalidation needs to be done without the spinlock.
*/
static void ux500_l2x0_inv_all(void)
{
void __iomem *base = l2x0_base;
uint32_t l2x0_way_mask = (1<<16) - 1; /* Bitmask of active ways */
/* invalidate all ways */
writel_relaxed(l2x0_way_mask, base + L2X0_INV_WAY);
ux500_cache_wait(base + L2X0_INV_WAY, l2x0_way_mask);
ux500_cache_sync();
}
static int ux500_l2x0_init(void)
{
if (cpu_is_u5500())
l2x0_base = __io_address(U5500_L2CC_BASE);
else if (cpu_is_u8500())
l2x0_base = __io_address(U8500_L2CC_BASE);
else
ux500_unknown_soc();
/* 64KB way size, 8 way associativity, force WA */
l2x0_init(l2x0_base, 0x3e060000, 0xc0000fff);
/* Override invalidate function */
outer_cache.disable = ux500_l2x0_disable;
outer_cache.inv_all = ux500_l2x0_inv_all;
return 0;
}
early_initcall(ux500_l2x0_init);
#endif
static void __init ux500_timer_init(void)
{
#ifdef CONFIG_LOCAL_TIMERS
/* Setup the local timer base */
if (cpu_is_u5500())
twd_base = __io_address(U5500_TWD_BASE);
else if (cpu_is_u8500())
twd_base = __io_address(U8500_TWD_BASE);
else
ux500_unknown_soc();
#endif
if (cpu_is_u5500())
mtu_base = __io_address(U5500_MTU0_BASE);
else if (cpu_is_u8500ed())
mtu_base = __io_address(U8500_MTU0_BASE_ED);
else if (cpu_is_u8500())
mtu_base = __io_address(U8500_MTU0_BASE);
else
ux500_unknown_soc();
nmdk_timer_init();
}
struct sys_timer ux500_timer = {
.init = ux500_timer_init,
};