kernel-ark/arch/mips/mips-boards/malta/malta_smtc.c
Kevin D. Kissell f571eff0a2 [MIPS] IRQ Affinity Support for SMTC on Malta Platform
Signed-off-by: Kevin D. Kissell <kevink@mips.com>
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
2007-10-11 23:45:57 +01:00

141 lines
3.4 KiB
C

/*
* Malta Platform-specific hooks for SMP operation
*/
#include <linux/irq.h>
#include <linux/init.h>
#include <asm/mipsregs.h>
#include <asm/mipsmtregs.h>
#include <asm/smtc.h>
#include <asm/smtc_ipi.h>
/* VPE/SMP Prototype implements platform interfaces directly */
/*
* Cause the specified action to be performed on a targeted "CPU"
*/
void core_send_ipi(int cpu, unsigned int action)
{
/* "CPU" may be TC of same VPE, VPE of same CPU, or different CPU */
smtc_send_ipi(cpu, LINUX_SMP_IPI, action);
}
/*
* Platform "CPU" startup hook
*/
void __cpuinit prom_boot_secondary(int cpu, struct task_struct *idle)
{
smtc_boot_secondary(cpu, idle);
}
/*
* Post-config but pre-boot cleanup entry point
*/
void __cpuinit prom_init_secondary(void)
{
void smtc_init_secondary(void);
int myvpe;
/* Don't enable Malta I/O interrupts (IP2) for secondary VPEs */
myvpe = read_c0_tcbind() & TCBIND_CURVPE;
if (myvpe != 0) {
/* Ideally, this should be done only once per VPE, but... */
clear_c0_status(ST0_IM);
set_c0_status((0x100 << cp0_compare_irq)
| (0x100 << MIPS_CPU_IPI_IRQ));
if (cp0_perfcount_irq >= 0)
set_c0_status(0x100 << cp0_perfcount_irq);
}
smtc_init_secondary();
}
/*
* Platform SMP pre-initialization
*
* As noted above, we can assume a single CPU for now
* but it may be multithreaded.
*/
void __cpuinit plat_smp_setup(void)
{
if (read_c0_config3() & (1<<2))
mipsmt_build_cpu_map(0);
}
void __init plat_prepare_cpus(unsigned int max_cpus)
{
if (read_c0_config3() & (1<<2))
mipsmt_prepare_cpus();
}
/*
* SMP initialization finalization entry point
*/
void __cpuinit prom_smp_finish(void)
{
smtc_smp_finish();
}
/*
* Hook for after all CPUs are online
*/
void prom_cpus_done(void)
{
}
#ifdef CONFIG_MIPS_MT_SMTC_IRQAFF
/*
* IRQ affinity hook
*/
void plat_set_irq_affinity(unsigned int irq, cpumask_t affinity)
{
cpumask_t tmask = affinity;
int cpu = 0;
void smtc_set_irq_affinity(unsigned int irq, cpumask_t aff);
/*
* On the legacy Malta development board, all I/O interrupts
* are routed through the 8259 and combined in a single signal
* to the CPU daughterboard, and on the CoreFPGA2/3 34K models,
* that signal is brought to IP2 of both VPEs. To avoid racing
* concurrent interrupt service events, IP2 is enabled only on
* one VPE, by convention VPE0. So long as no bits are ever
* cleared in the affinity mask, there will never be any
* interrupt forwarding. But as soon as a program or operator
* sets affinity for one of the related IRQs, we need to make
* sure that we don't ever try to forward across the VPE boundry,
* at least not until we engineer a system where the interrupt
* _ack() or _end() function can somehow know that it corresponds
* to an interrupt taken on another VPE, and perform the appropriate
* restoration of Status.IM state using MFTR/MTTR instead of the
* normal local behavior. We also ensure that no attempt will
* be made to forward to an offline "CPU".
*/
for_each_cpu_mask(cpu, affinity) {
if ((cpu_data[cpu].vpe_id != 0) || !cpu_online(cpu))
cpu_clear(cpu, tmask);
}
irq_desc[irq].affinity = tmask;
if (cpus_empty(tmask))
/*
* We could restore a default mask here, but the
* runtime code can anyway deal with the null set
*/
printk(KERN_WARNING
"IRQ affinity leaves no legal CPU for IRQ %d\n", irq);
/* Do any generic SMTC IRQ affinity setup */
smtc_set_irq_affinity(irq, tmask);
}
#endif /* CONFIG_MIPS_MT_SMTC_IRQAFF */