8531a35e5e
Rework of SMTC support to make it work with the new clock event system, allowing "tickless" operation, and to make it compatible with the use of the "wait_irqoff" idle loop. The new clocking scheme means that the previously optional IPI instant replay mechanism is now required, and has been made more robust. Signed-off-by: Kevin D. Kissell <kevink@paralogos.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
160 lines
4.1 KiB
C
160 lines
4.1 KiB
C
/*
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* Malta Platform-specific hooks for SMP operation
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*/
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#include <linux/irq.h>
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#include <linux/init.h>
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#include <asm/mipsregs.h>
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#include <asm/mipsmtregs.h>
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#include <asm/smtc.h>
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#include <asm/smtc_ipi.h>
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/* VPE/SMP Prototype implements platform interfaces directly */
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/*
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* Cause the specified action to be performed on a targeted "CPU"
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*/
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static void msmtc_send_ipi_single(int cpu, unsigned int action)
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{
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/* "CPU" may be TC of same VPE, VPE of same CPU, or different CPU */
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smtc_send_ipi(cpu, LINUX_SMP_IPI, action);
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}
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static void msmtc_send_ipi_mask(cpumask_t mask, unsigned int action)
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{
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unsigned int i;
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for_each_cpu_mask(i, mask)
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msmtc_send_ipi_single(i, action);
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}
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/*
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* Post-config but pre-boot cleanup entry point
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*/
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static void __cpuinit msmtc_init_secondary(void)
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{
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void smtc_init_secondary(void);
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int myvpe;
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/* Don't enable Malta I/O interrupts (IP2) for secondary VPEs */
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myvpe = read_c0_tcbind() & TCBIND_CURVPE;
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if (myvpe != 0) {
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/* Ideally, this should be done only once per VPE, but... */
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clear_c0_status(ST0_IM);
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set_c0_status((0x100 << cp0_compare_irq)
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| (0x100 << MIPS_CPU_IPI_IRQ));
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if (cp0_perfcount_irq >= 0)
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set_c0_status(0x100 << cp0_perfcount_irq);
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}
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smtc_init_secondary();
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}
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/*
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* Platform "CPU" startup hook
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*/
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static void __cpuinit msmtc_boot_secondary(int cpu, struct task_struct *idle)
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{
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smtc_boot_secondary(cpu, idle);
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}
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/*
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* SMP initialization finalization entry point
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*/
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static void __cpuinit msmtc_smp_finish(void)
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{
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smtc_smp_finish();
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}
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/*
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* Hook for after all CPUs are online
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*/
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static void msmtc_cpus_done(void)
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{
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}
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/*
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* Platform SMP pre-initialization
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*
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* As noted above, we can assume a single CPU for now
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* but it may be multithreaded.
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*/
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static void __init msmtc_smp_setup(void)
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{
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/*
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* we won't get the definitive value until
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* we've run smtc_prepare_cpus later, but
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* we would appear to need an upper bound now.
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*/
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smp_num_siblings = smtc_build_cpu_map(0);
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}
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static void __init msmtc_prepare_cpus(unsigned int max_cpus)
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{
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smtc_prepare_cpus(max_cpus);
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}
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struct plat_smp_ops msmtc_smp_ops = {
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.send_ipi_single = msmtc_send_ipi_single,
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.send_ipi_mask = msmtc_send_ipi_mask,
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.init_secondary = msmtc_init_secondary,
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.smp_finish = msmtc_smp_finish,
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.cpus_done = msmtc_cpus_done,
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.boot_secondary = msmtc_boot_secondary,
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.smp_setup = msmtc_smp_setup,
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.prepare_cpus = msmtc_prepare_cpus,
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};
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#ifdef CONFIG_MIPS_MT_SMTC_IRQAFF
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/*
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* IRQ affinity hook
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*/
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void plat_set_irq_affinity(unsigned int irq, cpumask_t affinity)
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{
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cpumask_t tmask = affinity;
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int cpu = 0;
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void smtc_set_irq_affinity(unsigned int irq, cpumask_t aff);
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/*
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* On the legacy Malta development board, all I/O interrupts
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* are routed through the 8259 and combined in a single signal
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* to the CPU daughterboard, and on the CoreFPGA2/3 34K models,
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* that signal is brought to IP2 of both VPEs. To avoid racing
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* concurrent interrupt service events, IP2 is enabled only on
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* one VPE, by convention VPE0. So long as no bits are ever
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* cleared in the affinity mask, there will never be any
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* interrupt forwarding. But as soon as a program or operator
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* sets affinity for one of the related IRQs, we need to make
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* sure that we don't ever try to forward across the VPE boundry,
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* at least not until we engineer a system where the interrupt
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* _ack() or _end() function can somehow know that it corresponds
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* to an interrupt taken on another VPE, and perform the appropriate
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* restoration of Status.IM state using MFTR/MTTR instead of the
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* normal local behavior. We also ensure that no attempt will
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* be made to forward to an offline "CPU".
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*/
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for_each_cpu_mask(cpu, affinity) {
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if ((cpu_data[cpu].vpe_id != 0) || !cpu_online(cpu))
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cpu_clear(cpu, tmask);
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}
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irq_desc[irq].affinity = tmask;
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if (cpus_empty(tmask))
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/*
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* We could restore a default mask here, but the
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* runtime code can anyway deal with the null set
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*/
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printk(KERN_WARNING
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"IRQ affinity leaves no legal CPU for IRQ %d\n", irq);
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/* Do any generic SMTC IRQ affinity setup */
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smtc_set_irq_affinity(irq, tmask);
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}
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#endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */
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