From 918af9f941af9995fcaa7ef1eb67c433a492e2b3 Mon Sep 17 00:00:00 2001
From: Grygorii Strashko <grygorii.strashko@ti.com>
Date: Mon, 16 Nov 2015 19:38:53 +0200
Subject: [PATCH] ARM: OMAP4+: SMP: use lockless clkdm/pwrdm api in
omap4_boot_secondary
OMAP CPU hotplug uses cpu1's clocks and power domains for CPU1 wake up
from low power states (or turn on CPU1). This part of code is also
part of system suspend (disable_nonboot_cpus()).
>From other side, cpu1's clocks and power domains are used by CPUIdle. All above
functionality is mutually exclusive and, therefore, lockless clkdm/pwrdm api
can be used in omap4_boot_secondary().
This fixes below back-trace on -RT which is triggered by
pwrdm_lock/unlock():
BUG: sleeping function called from invalid context at kernel/locking/rtmutex.c:917
in_atomic(): 1, irqs_disabled(): 0, pid: 118, name: sh
9 locks held by sh/118:
#0: (sb_writers#4){.+.+.+}, at: [<c0144a6c>] vfs_write+0x13c/0x164
#1: (&of->mutex){+.+.+.}, at: [<c01b4c70>] kernfs_fop_write+0x48/0x19c
#2: (s_active#24){.+.+.+}, at: [<c01b4c78>] kernfs_fop_write+0x50/0x19c
#3: (device_hotplug_lock){+.+.+.}, at: [<c03cbff0>] lock_device_hotplug_sysfs+0xc/0x4c
#4: (&dev->mutex){......}, at: [<c03cd284>] device_online+0x14/0x88
#5: (cpu_add_remove_lock){+.+.+.}, at: [<c003af90>] cpu_up+0x50/0x1a0
#6: (cpu_hotplug.lock){++++++}, at: [<c003ae48>] cpu_hotplug_begin+0x0/0xc4
#7: (cpu_hotplug.lock#2){+.+.+.}, at: [<c003aec0>] cpu_hotplug_begin+0x78/0xc4
#8: (boot_lock){+.+...}, at: [<c002b254>] omap4_boot_secondary+0x1c/0x178
Preemption disabled at:[< (null)>] (null)
CPU: 0 PID: 118 Comm: sh Not tainted 4.1.12-rt11-01998-gb4a62c3-dirty #137
Hardware name: Generic DRA74X (Flattened Device Tree)
[<c0017574>] (unwind_backtrace) from [<c0013be8>] (show_stack+0x10/0x14)
[<c0013be8>] (show_stack) from [<c05a8670>] (dump_stack+0x80/0x94)
[<c05a8670>] (dump_stack) from [<c05ad158>] (rt_spin_lock+0x24/0x54)
[<c05ad158>] (rt_spin_lock) from [<c0030dac>] (clkdm_wakeup+0x10/0x2c)
[<c0030dac>] (clkdm_wakeup) from [<c002b2c0>] (omap4_boot_secondary+0x88/0x178)
[<c002b2c0>] (omap4_boot_secondary) from [<c0015d00>] (__cpu_up+0xc4/0x164)
[<c0015d00>] (__cpu_up) from [<c003b09c>] (cpu_up+0x15c/0x1a0)
[<c003b09c>] (cpu_up) from [<c03cd2d4>] (device_online+0x64/0x88)
[<c03cd2d4>] (device_online) from [<c03cd360>] (online_store+0x68/0x74)
[<c03cd360>] (online_store) from [<c01b4ce0>] (kernfs_fop_write+0xb8/0x19c)
[<c01b4ce0>] (kernfs_fop_write) from [<c0144124>] (__vfs_write+0x20/0xd8)
[<c0144124>] (__vfs_write) from [<c01449c0>] (vfs_write+0x90/0x164)
[<c01449c0>] (vfs_write) from [<c01451e4>] (SyS_write+0x44/0x9c)
[<c01451e4>] (SyS_write) from [<c0010240>] (ret_fast_syscall+0x0/0x54)
CPU1: smp_ops.cpu_die() returned, trying to resuscitate
Cc: Tero Kristo <t-kristo@ti.com>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Tony Lindgren <tony@atomide.com>
---
arch/arm/mach-omap2/omap-smp.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/arch/arm/mach-omap2/omap-smp.c b/arch/arm/mach-omap2/omap-smp.c
index 5305ec7341eca..79e1f876d1c9b 100644
--- a/arch/arm/mach-omap2/omap-smp.c
+++ b/arch/arm/mach-omap2/omap-smp.c
@@ -143,9 +143,9 @@ static int omap4_boot_secondary(unsigned int cpu, struct task_struct *idle)
* Ensure that CPU power state is set to ON to avoid CPU
* powerdomain transition on wfi
*/
- clkdm_wakeup(cpu1_clkdm);
- omap_set_pwrdm_state(cpu1_pwrdm, PWRDM_POWER_ON);
- clkdm_allow_idle(cpu1_clkdm);
+ clkdm_wakeup_nolock(cpu1_clkdm);
+ pwrdm_set_next_pwrst(cpu1_pwrdm, PWRDM_POWER_ON);
+ clkdm_allow_idle_nolock(cpu1_clkdm);
if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD)) {
while (gic_dist_disabled()) {
--
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