42d02b81f2
There are a few key differences between doorbells on server compared with embedded that we care about on Linux, namely: - We have a new msgsndp instruction for directed privileged doorbells. msgsnd is used for directed hypervisor doorbells. - The tag we use in the instruction is the Thread Identification Register of the recipient thread (since server doorbells can only occur between threads within a single core), and is only 7 bits wide. - A new message type is introduced for server doorbells (none of the existing book3e message types are currently supported on book3s). Signed-off-by: Ian Munsie <imunsie@au1.ibm.com> Tested-by: Michael Neuling <mikey@neuling.org> Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
55 lines
1.2 KiB
C
55 lines
1.2 KiB
C
/*
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* Author: Kumar Gala <galak@kernel.crashing.org>
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*
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* Copyright 2009 Freescale Semiconductor Inc.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms of the GNU General Public License as published by the
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* Free Software Foundation; either version 2 of the License, or (at your
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* option) any later version.
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*/
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#include <linux/stddef.h>
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#include <linux/kernel.h>
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#include <linux/smp.h>
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#include <linux/threads.h>
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#include <linux/hardirq.h>
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#include <asm/dbell.h>
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#include <asm/irq_regs.h>
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#ifdef CONFIG_SMP
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void doorbell_setup_this_cpu(void)
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{
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unsigned long tag = mfspr(SPRN_DOORBELL_CPUTAG) & PPC_DBELL_TAG_MASK;
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smp_muxed_ipi_set_data(smp_processor_id(), tag);
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}
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void doorbell_cause_ipi(int cpu, unsigned long data)
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{
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/* Order previous accesses vs. msgsnd, which is treated as a store */
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mb();
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ppc_msgsnd(PPC_DBELL_MSGTYPE, 0, data);
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}
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void doorbell_exception(struct pt_regs *regs)
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{
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struct pt_regs *old_regs = set_irq_regs(regs);
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irq_enter();
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may_hard_irq_enable();
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smp_ipi_demux();
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irq_exit();
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set_irq_regs(old_regs);
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}
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#else /* CONFIG_SMP */
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void doorbell_exception(struct pt_regs *regs)
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{
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printk(KERN_WARNING "Received doorbell on non-smp system\n");
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}
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#endif /* CONFIG_SMP */
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