linux/arch/mips/mti-malta/malta-smtc.c
Kevin D. Kissell 8531a35e5e [MIPS] SMTC: Fix SMTC dyntick support.
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>
2008-10-03 17:58:58 +01:00

160 lines
4.1 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"
*/
static void msmtc_send_ipi_single(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);
}
static void msmtc_send_ipi_mask(cpumask_t mask, unsigned int action)
{
unsigned int i;
for_each_cpu_mask(i, mask)
msmtc_send_ipi_single(i, action);
}
/*
* Post-config but pre-boot cleanup entry point
*/
static void __cpuinit msmtc_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 "CPU" startup hook
*/
static void __cpuinit msmtc_boot_secondary(int cpu, struct task_struct *idle)
{
smtc_boot_secondary(cpu, idle);
}
/*
* SMP initialization finalization entry point
*/
static void __cpuinit msmtc_smp_finish(void)
{
smtc_smp_finish();
}
/*
* Hook for after all CPUs are online
*/
static void msmtc_cpus_done(void)
{
}
/*
* Platform SMP pre-initialization
*
* As noted above, we can assume a single CPU for now
* but it may be multithreaded.
*/
static void __init msmtc_smp_setup(void)
{
/*
* we won't get the definitive value until
* we've run smtc_prepare_cpus later, but
* we would appear to need an upper bound now.
*/
smp_num_siblings = smtc_build_cpu_map(0);
}
static void __init msmtc_prepare_cpus(unsigned int max_cpus)
{
smtc_prepare_cpus(max_cpus);
}
struct plat_smp_ops msmtc_smp_ops = {
.send_ipi_single = msmtc_send_ipi_single,
.send_ipi_mask = msmtc_send_ipi_mask,
.init_secondary = msmtc_init_secondary,
.smp_finish = msmtc_smp_finish,
.cpus_done = msmtc_cpus_done,
.boot_secondary = msmtc_boot_secondary,
.smp_setup = msmtc_smp_setup,
.prepare_cpus = msmtc_prepare_cpus,
};
#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 */