linux/arch/arm/mach-imx/src.c
Shawn Guo b6e23bb63f ARM: imx: remove imx_src_prepare_restart() call
There is ~10% possibility that the following emergency restart command
fails to reboot imx6q.

$ echo b > /proc/sysrq-trigger

The IMX restart routine mxc_restart() assumes that it will always run on
primary core, and will call imx_src_prepare_restart() to disable
secondary cores in order to get them come to online in the following
boot.  However, the assumption is only true for normal kernel_restart()
case where migrate_to_reboot_cpu() will be called to migrate to primary
core, but not necessarily true for emergency_restart() case.  So when
emergency_restart() calls into mxc_restart() on any secondary core,
system will hang immediately once imx_src_prepare_restart() is called
to disabled secondary cores.  Since emergency_restart() is defined as a
function that is safe to call in interrupt context, we cannot just call
migrate_to_reboot_cpu() to fix the issue.

Fortunately, we just found that the issue can be fixed at imx6q platform
level.  We used to call imx_src_prepare_restart() to disable all
secondary cores before resetting hardware.  Otherwise, the secondary
will fail come to online in the reboot.  However, we recently found that
after commit 6050d18 (ARM: imx: reset core along with enable/disable
operation) comes to play, we do not need to reset the secondary cores
any more.  That said, mxc_restart() now can run on any core to reboot
the system, as long as we remove the imx_src_prepare_restart() call from
mxc_restart().

So let's simply remove imx_src_prepare_restart() call to fix the above
emergency restart failure.

Reported-by: Jiada Wang <jiada_wang@mentor.com>
Signed-off-by: Shawn Guo <shawn.guo@linaro.org>
2013-11-11 22:58:43 +08:00

143 lines
3.3 KiB
C

/*
* Copyright 2011 Freescale Semiconductor, Inc.
* Copyright 2011 Linaro Ltd.
*
* The code contained herein is licensed under the GNU General Public
* License. You may obtain a copy of the GNU General Public License
* Version 2 or later at the following locations:
*
* http://www.opensource.org/licenses/gpl-license.html
* http://www.gnu.org/copyleft/gpl.html
*/
#include <linux/init.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/reset-controller.h>
#include <linux/smp.h>
#include <asm/smp_plat.h>
#include "common.h"
#define SRC_SCR 0x000
#define SRC_GPR1 0x020
#define BP_SRC_SCR_WARM_RESET_ENABLE 0
#define BP_SRC_SCR_SW_GPU_RST 1
#define BP_SRC_SCR_SW_VPU_RST 2
#define BP_SRC_SCR_SW_IPU1_RST 3
#define BP_SRC_SCR_SW_OPEN_VG_RST 4
#define BP_SRC_SCR_SW_IPU2_RST 12
#define BP_SRC_SCR_CORE1_RST 14
#define BP_SRC_SCR_CORE1_ENABLE 22
static void __iomem *src_base;
static DEFINE_SPINLOCK(scr_lock);
static const int sw_reset_bits[5] = {
BP_SRC_SCR_SW_GPU_RST,
BP_SRC_SCR_SW_VPU_RST,
BP_SRC_SCR_SW_IPU1_RST,
BP_SRC_SCR_SW_OPEN_VG_RST,
BP_SRC_SCR_SW_IPU2_RST
};
static int imx_src_reset_module(struct reset_controller_dev *rcdev,
unsigned long sw_reset_idx)
{
unsigned long timeout;
unsigned long flags;
int bit;
u32 val;
if (!src_base)
return -ENODEV;
if (sw_reset_idx >= ARRAY_SIZE(sw_reset_bits))
return -EINVAL;
bit = 1 << sw_reset_bits[sw_reset_idx];
spin_lock_irqsave(&scr_lock, flags);
val = readl_relaxed(src_base + SRC_SCR);
val |= bit;
writel_relaxed(val, src_base + SRC_SCR);
spin_unlock_irqrestore(&scr_lock, flags);
timeout = jiffies + msecs_to_jiffies(1000);
while (readl(src_base + SRC_SCR) & bit) {
if (time_after(jiffies, timeout))
return -ETIME;
cpu_relax();
}
return 0;
}
static struct reset_control_ops imx_src_ops = {
.reset = imx_src_reset_module,
};
static struct reset_controller_dev imx_reset_controller = {
.ops = &imx_src_ops,
.nr_resets = ARRAY_SIZE(sw_reset_bits),
};
void imx_enable_cpu(int cpu, bool enable)
{
u32 mask, val;
cpu = cpu_logical_map(cpu);
mask = 1 << (BP_SRC_SCR_CORE1_ENABLE + cpu - 1);
spin_lock(&scr_lock);
val = readl_relaxed(src_base + SRC_SCR);
val = enable ? val | mask : val & ~mask;
val |= 1 << (BP_SRC_SCR_CORE1_RST + cpu - 1);
writel_relaxed(val, src_base + SRC_SCR);
spin_unlock(&scr_lock);
}
void imx_set_cpu_jump(int cpu, void *jump_addr)
{
cpu = cpu_logical_map(cpu);
writel_relaxed(virt_to_phys(jump_addr),
src_base + SRC_GPR1 + cpu * 8);
}
u32 imx_get_cpu_arg(int cpu)
{
cpu = cpu_logical_map(cpu);
return readl_relaxed(src_base + SRC_GPR1 + cpu * 8 + 4);
}
void imx_set_cpu_arg(int cpu, u32 arg)
{
cpu = cpu_logical_map(cpu);
writel_relaxed(arg, src_base + SRC_GPR1 + cpu * 8 + 4);
}
void __init imx_src_init(void)
{
struct device_node *np;
u32 val;
np = of_find_compatible_node(NULL, NULL, "fsl,imx51-src");
if (!np)
return;
src_base = of_iomap(np, 0);
WARN_ON(!src_base);
imx_reset_controller.of_node = np;
if (IS_ENABLED(CONFIG_RESET_CONTROLLER))
reset_controller_register(&imx_reset_controller);
/*
* force warm reset sources to generate cold reset
* for a more reliable restart
*/
spin_lock(&scr_lock);
val = readl_relaxed(src_base + SRC_SCR);
val &= ~(1 << BP_SRC_SCR_WARM_RESET_ENABLE);
writel_relaxed(val, src_base + SRC_SCR);
spin_unlock(&scr_lock);
}