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sparc32,leon: Implemented SMP IPIs for LEON CPU 

This patch implements SMP IPIs on LEON using software generated
IRQs to signal between CPUs.

The IPI IRQ number is set by using the ipi_num property in the
device tree, or defaults to 13. LEON SMP systems should reserve
IRQ 13 (and IRQ 15) to Linux in order for the defaults to work.

Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Daniel Hellstrom 2011-05-02 00:08:52 +00:00 committed by David S. Miller
parent d6d048192b
commit 1ca0c808c6
3 changed files with 126 additions and 3 deletions
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4
arch/sparc/include/asm/leon.h
View File

@ -215,7 +215,7 @@ static inline int sparc_leon3_cpuid(void)
#endif /*!__ASSEMBLY__*/
#ifdef CONFIG_SMP
# define LEON3_IRQ_RESCHEDULE 13
# define LEON3_IRQ_IPI_DEFAULT 13
# define LEON3_IRQ_TICKER (leon3_ticker_irq)
# define LEON3_IRQ_CROSS_CALL 15
#endif
@ -351,9 +351,11 @@ void leon_enable_irq_cpu(unsigned int irq_nr, unsigned int cpu);
extern irqreturn_t leon_percpu_timer_interrupt(int irq, void *unused);
extern unsigned int real_irq_entry[];
extern unsigned int smpleon_ipi[];
extern unsigned int patchme_maybe_smp_msg[];
extern unsigned int t_nmi[], linux_trap_ipi15_leon[];
extern unsigned int linux_trap_ipi15_sun4m[];
extern int leon_ipi_irq;
#endif /* CONFIG_SMP */

16
arch/sparc/kernel/entry.S
View File

@ -401,6 +401,22 @@ linux_trap_ipi15_sun4d:
1: b,a 1b
#ifdef CONFIG_SPARC_LEON
.globl smpleon_ipi
.extern leon_ipi_interrupt
/* SMP per-cpu IPI interrupts are handled specially. */
smpleon_ipi:
SAVE_ALL
or %l0, PSR_PIL, %g2
wr %g2, 0x0, %psr
WRITE_PAUSE
wr %g2, PSR_ET, %psr
WRITE_PAUSE
call leonsmp_ipi_interrupt
add %sp, STACKFRAME_SZ, %o1 ! pt_regs
wr %l0, PSR_ET, %psr
WRITE_PAUSE
RESTORE_ALL
.align 4
.globl linux_trap_ipi15_leon
linux_trap_ipi15_leon:

109
arch/sparc/kernel/leon_smp.c
View File

@ -14,6 +14,7 @@
#include <linux/smp.h>
#include <linux/interrupt.h>
#include <linux/kernel_stat.h>
#include <linux/of.h>
#include <linux/init.h>
#include <linux/spinlock.h>
#include <linux/mm.h>
@ -29,6 +30,7 @@
#include <asm/ptrace.h>
#include <asm/atomic.h>
#include <asm/irq_regs.h>
#include <asm/traps.h>
#include <asm/delay.h>
#include <asm/irq.h>
@ -52,6 +54,10 @@ static int smp_processors_ready;
extern volatile unsigned long cpu_callin_map[NR_CPUS];
extern cpumask_t smp_commenced_mask;
void __init leon_configure_cache_smp(void);
static void leon_ipi_init(void);
/* IRQ number of LEON IPIs */
int leon_ipi_irq = LEON3_IRQ_IPI_DEFAULT;
static inline unsigned long do_swap(volatile unsigned long *ptr,
unsigned long val)
@ -176,13 +182,16 @@ void __init leon_boot_cpus(void)
int nrcpu = leon_smp_nrcpus();
int me = smp_processor_id();
/* Setup IPI */
leon_ipi_init();
printk(KERN_INFO "%d:(%d:%d) cpus mpirq at 0x%x\n", (unsigned int)me,
(unsigned int)nrcpu, (unsigned int)NR_CPUS,
(unsigned int)&(leon3_irqctrl_regs->mpstatus));
leon_enable_irq_cpu(LEON3_IRQ_CROSS_CALL, me);
leon_enable_irq_cpu(LEON3_IRQ_TICKER, me);
leon_enable_irq_cpu(LEON3_IRQ_RESCHEDULE, me);
leon_enable_irq_cpu(leon_ipi_irq, me);
leon_smp_setbroadcast(1 << LEON3_IRQ_TICKER);
@ -237,7 +246,7 @@ int __cpuinit leon_boot_one_cpu(int i)
} else {
leon_enable_irq_cpu(LEON3_IRQ_CROSS_CALL, i);
leon_enable_irq_cpu(LEON3_IRQ_TICKER, i);
leon_enable_irq_cpu(LEON3_IRQ_RESCHEDULE, i);
leon_enable_irq_cpu(leon_ipi_irq, i);
}
local_flush_cache_all();
@ -293,6 +302,99 @@ void leon_irq_rotate(int cpu)
{
}
struct leon_ipi_work {
int single;
int msk;
int resched;
};
static DEFINE_PER_CPU_SHARED_ALIGNED(struct leon_ipi_work, leon_ipi_work);
/* Initialize IPIs on the LEON, in order to save IRQ resources only one IRQ
* is used for all three types of IPIs.
*/
static void __init leon_ipi_init(void)
{
int cpu, len;
struct leon_ipi_work *work;
struct property *pp;
struct device_node *rootnp;
struct tt_entry *trap_table;
unsigned long flags;
/* Find IPI IRQ or stick with default value */
rootnp = of_find_node_by_path("/ambapp0");
if (rootnp) {
pp = of_find_property(rootnp, "ipi_num", &len);
if (pp && (*(int *)pp->value))
leon_ipi_irq = *(int *)pp->value;
}
printk(KERN_INFO "leon: SMP IPIs at IRQ %d\n", leon_ipi_irq);
/* Adjust so that we jump directly to smpleon_ipi */
local_irq_save(flags);
trap_table = &sparc_ttable[SP_TRAP_IRQ1 + (leon_ipi_irq - 1)];
trap_table->inst_three += smpleon_ipi - real_irq_entry;
local_flush_cache_all();
local_irq_restore(flags);
for_each_possible_cpu(cpu) {
work = &per_cpu(leon_ipi_work, cpu);
work->single = work->msk = work->resched = 0;
}
}
static void leon_ipi_single(int cpu)
{
struct leon_ipi_work *work = &per_cpu(leon_ipi_work, cpu);
/* Mark work */
work->single = 1;
/* Generate IRQ on the CPU */
set_cpu_int(cpu, leon_ipi_irq);
}
static void leon_ipi_mask_one(int cpu)
{
struct leon_ipi_work *work = &per_cpu(leon_ipi_work, cpu);
/* Mark work */
work->msk = 1;
/* Generate IRQ on the CPU */
set_cpu_int(cpu, leon_ipi_irq);
}
static void leon_ipi_resched(int cpu)
{
struct leon_ipi_work *work = &per_cpu(leon_ipi_work, cpu);
/* Mark work */
work->resched = 1;
/* Generate IRQ on the CPU (any IRQ will cause resched) */
set_cpu_int(cpu, leon_ipi_irq);
}
void leonsmp_ipi_interrupt(void)
{
struct leon_ipi_work *work = &__get_cpu_var(leon_ipi_work);
if (work->single) {
work->single = 0;
smp_call_function_single_interrupt();
}
if (work->msk) {
work->msk = 0;
smp_call_function_interrupt();
}
if (work->resched) {
work->resched = 0;
smp_resched_interrupt();
}
}
static struct smp_funcall {
smpfunc_t func;
unsigned long arg1;
@ -446,6 +548,9 @@ void __init leon_init_smp(void)
BTFIXUPSET_CALL(smp_cross_call, leon_cross_call, BTFIXUPCALL_NORM);
BTFIXUPSET_CALL(__hard_smp_processor_id, __leon_processor_id,
BTFIXUPCALL_NORM);
BTFIXUPSET_CALL(smp_ipi_resched, leon_ipi_resched, BTFIXUPCALL_NORM);
BTFIXUPSET_CALL(smp_ipi_single, leon_ipi_single, BTFIXUPCALL_NORM);
BTFIXUPSET_CALL(smp_ipi_mask_one, leon_ipi_mask_one, BTFIXUPCALL_NORM);
}
#endif /* CONFIG_SPARC_LEON */