forked from luck/tmp_suning_uos_patched
[PATCH] powerpc: work around a cell interrupt HW bug
Apparently we have found a bug in the CPU that causes external interrupts to sometimes get disabled indefinitely. This adds a workaround for the problem. Signed-off-by: Arnd Bergmann <arnd.bergmann@de.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
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@ -63,7 +63,24 @@ static DEFINE_PER_CPU(struct iic, iic);
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void iic_local_enable(void)
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{
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out_be64(&__get_cpu_var(iic).regs->prio, 0xff);
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struct iic *iic = &__get_cpu_var(iic);
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u64 tmp;
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/*
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* There seems to be a bug that is present in DD2.x CPUs
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* and still only partially fixed in DD3.1.
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* This bug causes a value written to the priority register
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* not to make it there, resulting in a system hang unless we
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* write it again.
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* Masking with 0xf0 is done because the Cell BE does not
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* implement the lower four bits of the interrupt priority,
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* they always read back as zeroes, although future CPUs
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* might implement different bits.
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*/
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do {
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out_be64(&iic->regs->prio, 0xff);
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tmp = in_be64(&iic->regs->prio);
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} while ((tmp & 0xf0) != 0xf0);
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}
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void iic_local_disable(void)
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