b6e23bb63f
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>
142 lines
3.3 KiB
C
142 lines
3.3 KiB
C
/*
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* Copyright 2011 Freescale Semiconductor, Inc.
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* Copyright 2011 Linaro Ltd.
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*
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* The code contained herein is licensed under the GNU General Public
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* License. You may obtain a copy of the GNU General Public License
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* Version 2 or later at the following locations:
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*
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* http://www.opensource.org/licenses/gpl-license.html
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* http://www.gnu.org/copyleft/gpl.html
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*/
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#include <linux/init.h>
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#include <linux/io.h>
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#include <linux/of.h>
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#include <linux/of_address.h>
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#include <linux/reset-controller.h>
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#include <linux/smp.h>
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#include <asm/smp_plat.h>
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#include "common.h"
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#define SRC_SCR 0x000
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#define SRC_GPR1 0x020
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#define BP_SRC_SCR_WARM_RESET_ENABLE 0
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#define BP_SRC_SCR_SW_GPU_RST 1
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#define BP_SRC_SCR_SW_VPU_RST 2
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#define BP_SRC_SCR_SW_IPU1_RST 3
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#define BP_SRC_SCR_SW_OPEN_VG_RST 4
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#define BP_SRC_SCR_SW_IPU2_RST 12
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#define BP_SRC_SCR_CORE1_RST 14
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#define BP_SRC_SCR_CORE1_ENABLE 22
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static void __iomem *src_base;
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static DEFINE_SPINLOCK(scr_lock);
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static const int sw_reset_bits[5] = {
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BP_SRC_SCR_SW_GPU_RST,
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BP_SRC_SCR_SW_VPU_RST,
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BP_SRC_SCR_SW_IPU1_RST,
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BP_SRC_SCR_SW_OPEN_VG_RST,
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BP_SRC_SCR_SW_IPU2_RST
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};
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static int imx_src_reset_module(struct reset_controller_dev *rcdev,
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unsigned long sw_reset_idx)
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{
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unsigned long timeout;
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unsigned long flags;
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int bit;
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u32 val;
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if (!src_base)
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return -ENODEV;
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if (sw_reset_idx >= ARRAY_SIZE(sw_reset_bits))
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return -EINVAL;
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bit = 1 << sw_reset_bits[sw_reset_idx];
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spin_lock_irqsave(&scr_lock, flags);
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val = readl_relaxed(src_base + SRC_SCR);
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val |= bit;
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writel_relaxed(val, src_base + SRC_SCR);
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spin_unlock_irqrestore(&scr_lock, flags);
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timeout = jiffies + msecs_to_jiffies(1000);
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while (readl(src_base + SRC_SCR) & bit) {
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if (time_after(jiffies, timeout))
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return -ETIME;
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cpu_relax();
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}
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return 0;
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}
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static struct reset_control_ops imx_src_ops = {
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.reset = imx_src_reset_module,
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};
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static struct reset_controller_dev imx_reset_controller = {
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.ops = &imx_src_ops,
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.nr_resets = ARRAY_SIZE(sw_reset_bits),
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};
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void imx_enable_cpu(int cpu, bool enable)
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{
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u32 mask, val;
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cpu = cpu_logical_map(cpu);
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mask = 1 << (BP_SRC_SCR_CORE1_ENABLE + cpu - 1);
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spin_lock(&scr_lock);
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val = readl_relaxed(src_base + SRC_SCR);
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val = enable ? val | mask : val & ~mask;
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val |= 1 << (BP_SRC_SCR_CORE1_RST + cpu - 1);
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writel_relaxed(val, src_base + SRC_SCR);
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spin_unlock(&scr_lock);
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}
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void imx_set_cpu_jump(int cpu, void *jump_addr)
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{
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cpu = cpu_logical_map(cpu);
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writel_relaxed(virt_to_phys(jump_addr),
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src_base + SRC_GPR1 + cpu * 8);
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}
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u32 imx_get_cpu_arg(int cpu)
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{
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cpu = cpu_logical_map(cpu);
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return readl_relaxed(src_base + SRC_GPR1 + cpu * 8 + 4);
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}
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void imx_set_cpu_arg(int cpu, u32 arg)
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{
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cpu = cpu_logical_map(cpu);
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writel_relaxed(arg, src_base + SRC_GPR1 + cpu * 8 + 4);
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}
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void __init imx_src_init(void)
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{
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struct device_node *np;
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u32 val;
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np = of_find_compatible_node(NULL, NULL, "fsl,imx51-src");
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if (!np)
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return;
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src_base = of_iomap(np, 0);
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WARN_ON(!src_base);
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imx_reset_controller.of_node = np;
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if (IS_ENABLED(CONFIG_RESET_CONTROLLER))
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reset_controller_register(&imx_reset_controller);
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/*
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* force warm reset sources to generate cold reset
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* for a more reliable restart
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*/
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spin_lock(&scr_lock);
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val = readl_relaxed(src_base + SRC_SCR);
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val &= ~(1 << BP_SRC_SCR_WARM_RESET_ENABLE);
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writel_relaxed(val, src_base + SRC_SCR);
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spin_unlock(&scr_lock);
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}
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