minix/kernel/arch/earm/arch_system.c
Thomas Cort 6d7eff8023 kernel: add support for am335x PMIC-base power-off
AM335X SoCs support power-off via a power management
chip (PMIC). An alarm in the real time clock is used
to trigger the PMIC to cut the power.

To ensure the alarm goes off when the system is in
a safe state, the RTC is frozen when the alarm is
set. At the last moment, the kernel unfreezes the RTC
to let the alarm go off.

This patch adds a mini driver for unfreezing the RTC
as well as code to handle RBT_POWEROFF on Minix/arm.

Change-Id: I7d48e75791e3a81bdd2f7704997193a269409fe8
2013-08-05 10:22:59 -04:00

219 lines
5 KiB
C

/* system dependent functions for use inside the whole kernel. */
#include "kernel/kernel.h"
#include <unistd.h>
#include <ctype.h>
#include <string.h>
#include <minix/cpufeature.h>
#include <assert.h>
#include <signal.h>
#include <machine/vm.h>
#include <minix/u64.h>
#include "archconst.h"
#include "arch_proto.h"
#include "serial.h"
#include "kernel/proc.h"
#include "kernel/debug.h"
#include "omap_ccnt.h"
#include "omap_padconf.h"
#include "glo.h"
void * k_stacks;
static void ser_init(void);
void fpu_init(void)
{
}
void save_local_fpu(struct proc *pr, int retain)
{
}
void save_fpu(struct proc *pr)
{
}
void arch_proc_reset(struct proc *pr)
{
assert(pr->p_nr < NR_PROCS);
/* Clear process state. */
memset(&pr->p_reg, 0, sizeof(pr->p_reg));
if(iskerneln(pr->p_nr))
pr->p_reg.psr = INIT_TASK_PSR;
else
pr->p_reg.psr = INIT_PSR;
}
void arch_proc_setcontext(struct proc *p, struct stackframe_s *state,
int isuser, int trapstyle)
{
assert(sizeof(p->p_reg) == sizeof(*state));
memcpy(&p->p_reg, state, sizeof(*state));
/* further code is instructed to not touch the context
* any more
*/
p->p_misc_flags |= MF_CONTEXT_SET;
if(!(p->p_rts_flags)) {
printf("WARNINIG: setting full context of runnable process\n");
print_proc(p);
util_stacktrace();
}
}
void arch_set_secondary_ipc_return(struct proc *p, u32_t val)
{
p->p_reg.r1 = val;
}
int restore_fpu(struct proc *pr)
{
return 0;
}
void cpu_identify(void)
{
u32_t midr;
unsigned cpu = cpuid;
asm volatile("mrc p15, 0, %[midr], c0, c0, 0 @ read MIDR\n\t"
: [midr] "=r" (midr));
cpu_info[cpu].implementer = midr >> 24;
cpu_info[cpu].variant = (midr >> 20) & 0xF;
cpu_info[cpu].arch = (midr >> 16) & 0xF;
cpu_info[cpu].part = (midr >> 4) & 0xFFF;
cpu_info[cpu].revision = midr & 0xF;
cpu_info[cpu].freq = 660; /* 660 Mhz hardcoded */
}
void arch_init(void)
{
u32_t value;
k_stacks = (void*) &k_stacks_start;
assert(!((vir_bytes) k_stacks % K_STACK_SIZE));
#ifndef CONFIG_SMP
/*
* use stack 0 and cpu id 0 on a single processor machine, SMP
* configuration does this in smp_init() for all cpus at once
*/
tss_init(0, get_k_stack_top(0));
#endif
ser_init();
/* enable user space access to cycle counter */
/* set cycle counter to 0: ARM ARM B4.1.113 and B4.1.117 */
asm volatile ("MRC p15, 0, %0, c9, c12, 0\t\n": "=r" (value));
value |= OMAP_PMCR_C; /* Reset counter */
value |= OMAP_PMCR_E; /* Enable counter hardware */
asm volatile ("MCR p15, 0, %0, c9, c12, 0\t\n": : "r" (value));
/* enable CCNT counting: ARM ARM B4.1.116 */
value = OMAP_PMCNTENSET_C; /* Enable PMCCNTR cycle counter */
asm volatile ("MCR p15, 0, %0, c9, c12, 1\t\n": : "r" (value));
/* enable cycle counter in user mode: ARM ARM B4.1.124 */
value = OMAP_PMUSERENR_EN;
asm volatile ("MCR p15, 0, %0, c9, c14, 0\t\n": : "r" (value));
/* configure i2c pinmux */
omap3_padconf_init();
/* map memory for rtc */
omap3_rtc_init();
}
/*===========================================================================*
* do_ser_debug *
*===========================================================================*/
void do_ser_debug()
{
}
void arch_do_syscall(struct proc *proc)
{
/* do_ipc assumes that it's running because of the current process */
assert(proc == get_cpulocal_var(proc_ptr));
/* Make the system call, for real this time. */
proc->p_reg.retreg =
do_ipc(proc->p_reg.retreg, proc->p_reg.r1, proc->p_reg.r2);
}
reg_t svc_stack;
struct proc * arch_finish_switch_to_user(void)
{
char * stk;
struct proc * p;
#ifdef CONFIG_SMP
stk = (char *)tss[cpuid].sp0;
#else
stk = (char *)tss[0].sp0;
#endif
svc_stack = (reg_t)stk;
/* set pointer to the process to run on the stack */
p = get_cpulocal_var(proc_ptr);
*((reg_t *)stk) = (reg_t) p;
/* turn interrupts on */
p->p_reg.psr &= ~(PSR_I|PSR_F);
return p;
}
void fpu_sigcontext(struct proc *pr, struct sigframe *fr, struct sigcontext *sc)
{
}
reg_t arch_get_sp(struct proc *p) { return p->p_reg.sp; }
void get_randomness(struct k_randomness *rand, int source)
{
}
static void ser_init(void)
{
}
/*===========================================================================*/
/* __switch_address_space */
/*===========================================================================*/
/*
* sets the ttbr register to the supplied value if it is not already set to the
* same value in which case it would only result in an extra TLB flush which is
* not desirable
*/
void __switch_address_space(struct proc *p, struct proc **__ptproc)
{
reg_t orig_ttbr, new_ttbr;
new_ttbr = p->p_seg.p_ttbr;
if (new_ttbr == 0)
return;
orig_ttbr = read_ttbr0();
/*
* test if ttbr is loaded with the current value to avoid unnecessary
* TLB flushes
*/
if (new_ttbr == orig_ttbr)
return;
write_ttbr0(new_ttbr);
*__ptproc = p;
return;
}