linux-sg2042/arch/sh/boards/saturn/smp.c

69 lines
1.3 KiB
C

/*
* arch/sh/boards/saturn/smp.c
*
* SMP support for the Sega Saturn.
*
* Copyright (c) 2002 Paul Mundt
*
* Released under the terms of the GNU GPL v2.0.
*/
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/smp.h>
#include <asm/saturn/smpc.h>
extern void start_secondary(void);
void __smp_send_ipi(unsigned int cpu, unsigned int action)
{
/* Nothing here yet .. */
}
unsigned int __smp_probe_cpus(void)
{
/*
* This is just a straightforward master/slave configuration,
* and probing isn't really supported..
*/
return 2;
}
/*
* We're only allowed to do byte-access to SMPC registers. In
* addition to which, we treat them as write-only, since
* reading from them will return undefined data.
*/
static inline void smpc_slave_stop(unsigned int cpu)
{
smpc_barrier();
ctrl_outb(1, SMPC_STATUS);
ctrl_outb(SMPC_CMD_SSHOFF, SMPC_COMMAND);
smpc_barrier();
}
static inline void smpc_slave_start(unsigned int cpu)
{
ctrl_outb(1, SMPC_STATUS);
ctrl_outb(SMPC_CMD_SSHON, SMPC_COMMAND);
smpc_barrier();
}
void __smp_slave_init(unsigned int cpu)
{
register unsigned long vbr;
void **entry;
__asm__ __volatile__ ("stc vbr, %0\n\t" : "=r" (vbr));
entry = (void **)(vbr + 0x310 + 0x94);
smpc_slave_stop(cpu);
*(void **)entry = (void *)start_secondary;
smpc_slave_start(cpu);
}