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tty/serial/pl011: Make the locking work on RT 

The lock is a sleeping lock and local_irq_save() is not the optimsation
we are looking for. Redo it to make it work on -RT and non-RT.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
This commit is contained in:
Thomas Gleixner 2013-01-08 21:36:51 +01:00 committed by Alibek Omarov
parent a52d193315
commit 6d505b3185
1 changed files with 10 additions and 5 deletions
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15
drivers/tty/serial/amba-pl011.c
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@ -2196,13 +2196,19 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
clk_enable(uap->clk);
local_irq_save(flags);
/*
* local_irq_save(flags);
*
* This local_irq_save() is nonsense. If we come in via sysrq
* handling then interrupts are already disabled. Aside of
* that the port.sysrq check is racy on SMP regardless.
*/
if (uap->port.sysrq)
locked = 0;
else if (oops_in_progress)
locked = spin_trylock(&uap->port.lock);
locked = spin_trylock_irqsave(&uap->port.lock, flags);
else
spin_lock(&uap->port.lock);
spin_lock_irqsave(&uap->port.lock, flags);
/*
* First save the CR then disable the interrupts
@ -2228,8 +2234,7 @@ pl011_console_write(struct console *co, const char *s, unsigned int count)
pl011_write(old_cr, uap, REG_CR);
if (locked)
spin_unlock(&uap->port.lock);
local_irq_restore(flags);
spin_unlock_irqrestore(&uap->port.lock, flags);
clk_disable(uap->clk);
}