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grygoriyStmlind
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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 <[email protected]> Signed-off-by: Grygorii Strashko <[email protected]> Signed-off-by: Tony Lindgren <[email protected]>
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arch/arm/mach-omap2/omap-smp.c

Lines changed: 3 additions & 3 deletions
Original file line numberDiff line numberDiff line change
@@ -143,9 +143,9 @@ static int omap4_boot_secondary(unsigned int cpu, struct task_struct *idle)
143143
* Ensure that CPU power state is set to ON to avoid CPU
144144
* powerdomain transition on wfi
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*/
146-
clkdm_wakeup(cpu1_clkdm);
147-
omap_set_pwrdm_state(cpu1_pwrdm, PWRDM_POWER_ON);
148-
clkdm_allow_idle(cpu1_clkdm);
146+
clkdm_wakeup_nolock(cpu1_clkdm);
147+
pwrdm_set_next_pwrst(cpu1_pwrdm, PWRDM_POWER_ON);
148+
clkdm_allow_idle_nolock(cpu1_clkdm);
149149

150150
if (IS_PM44XX_ERRATUM(PM_OMAP4_ROM_SMP_BOOT_ERRATUM_GICD)) {
151151
while (gic_dist_disabled()) {

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