/*
* chopstx.c - Threads and only threads.
*
* Copyright (C) 2013, 2014, 2015 Flying Stone Technology
* Author: NIIBE Yutaka <gniibe@fsij.org>
*
* This file is a part of Chopstx, a thread library for embedded.
*
* Chopstx is free software: you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* Chopstx is distributed in the hope that it will be useful, but
* WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*
* As additional permission under GNU GPL version 3 section 7, you may
* distribute non-source form of the Program without the copy of the
* GNU GPL normally required by section 4, provided you inform the
* receipents of GNU GPL by a written offer.
*
*/
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <chopstx.h>
/*
* Thread priority: higer has higher precedence.
*/
#if !defined(CHX_PRIO_MAIN_INIT)
#define CHX_PRIO_MAIN_INIT 1
#endif
#if !defined(CHX_FLAGS_MAIN)
#define CHX_FLAGS_MAIN 0
#endif
/* Constant for round robin scheduling. */
#if !defined(PREEMPTION_USEC)
#define PREEMPTION_USEC 1000 /* 1ms */
#endif
#define MAX_PRIO (255+1)
/*
* Exception priority: lower has higher precedence.
*
* Prio 0x30: svc
* ---------------------
* Prio 0x40: thread temporarily inhibiting schedule for critical region
* ...
* Prio 0xb0: systick, external interrupt
* Prio 0xc0: pendsv
*/
#define CPU_EXCEPTION_PRIORITY_CLEAR 0
#if defined(__ARM_ARCH_6M__)
#define CPU_EXCEPTION_PRIORITY_SVC 0x00
#define CPU_EXCEPTION_PRIORITY_INHIBIT_SCHED 0x40
/* ... */
#define CPU_EXCEPTION_PRIORITY_SYSTICK CPU_EXCEPTION_PRIORITY_INTERRUPT
#define CPU_EXCEPTION_PRIORITY_INTERRUPT 0x80
#define CPU_EXCEPTION_PRIORITY_PENDSV 0xc0
#elif defined(__ARM_ARCH_7M__)
#define CPU_EXCEPTION_PRIORITY_SVC 0x30
#define CPU_EXCEPTION_PRIORITY_INHIBIT_SCHED 0x40
/* ... */
#define CPU_EXCEPTION_PRIORITY_SYSTICK CPU_EXCEPTION_PRIORITY_INTERRUPT
#define CPU_EXCEPTION_PRIORITY_INTERRUPT 0xb0
#define CPU_EXCEPTION_PRIORITY_PENDSV 0xc0
#else
#error "no support for this arch"
#endif
/*
* Lower layer architecture specific functions.
*
* system tick and interrupt
*/
/*
* System tick
*/
/* SysTick registers. */
static volatile uint32_t *const SYST_CSR = (uint32_t *const)0xE000E010;
static volatile uint32_t *const SYST_RVR = (uint32_t *const)0xE000E014;
static volatile uint32_t *const SYST_CVR = (uint32_t *const)0xE000E018;
static void
chx_systick_reset (void)
{
*SYST_RVR = 0;
*SYST_CVR = 0;
*SYST_CSR = 7;
}
static void
chx_systick_reload (uint32_t ticks)
{
*SYST_RVR = ticks;
*SYST_CVR = 0; /* write (any) to clear the counter to reload. */
*SYST_RVR = 0;
}
static uint32_t
chx_systick_get (void)
{
return *SYST_CVR;
}
#ifndef MHZ
#define MHZ 72
#endif
static uint32_t usec_to_ticks (uint32_t usec)
{
return usec * MHZ;
}
/*
* Interrupt Handling
*/
/* NVIC: Nested Vectored Interrupt Controller. */
struct NVIC {
uint32_t ISER[8];
uint32_t unused1[24];
uint32_t ICER[8];
uint32_t unused2[24];
uint32_t ISPR[8];
uint32_t unused3[24];
uint32_t ICPR[8];
uint32_t unused4[24];
uint32_t IABR[8];
uint32_t unused5[56];
uint32_t IPR[60];
};
static struct NVIC *const NVIC = (struct NVIC *const)0xE000E100;
#define NVIC_ISER(n) (NVIC->ISER[n >> 5])
#define NVIC_ICER(n) (NVIC->ICER[n >> 5])
#define NVIC_ICPR(n) (NVIC->ICPR[n >> 5])
#define NVIC_IPR(n) (NVIC->IPR[n >> 2])
#define USB_LP_CAN1_RX0_IRQn 20
static void
chx_enable_intr (uint8_t irq_num)
{
NVIC_ISER (irq_num) = 1 << (irq_num & 0x1f);
}
static void
chx_clr_intr (uint8_t irq_num)
{ /* Clear pending interrupt. */
NVIC_ICPR (irq_num) = 1 << (irq_num & 0x1f);
}
static void
chx_disable_intr (uint8_t irq_num)
{
NVIC_ICER (irq_num) = 1 << (irq_num & 0x1f);
}
static void
chx_set_intr_prio (uint8_t n)
{
unsigned int sh = (n & 3) << 3;
NVIC_IPR (n) = (NVIC_IPR(n) & ~(0xFF << sh))
| (CPU_EXCEPTION_PRIORITY_INTERRUPT << sh);
}
static volatile uint32_t *const ICSR = (uint32_t *const)0xE000ED04;
/* Priority control. */
static uint32_t *const AIRCR = (uint32_t *const)0xE000ED0C;
static uint32_t *const SHPR2 = (uint32_t *const)0xE000ED1C;
static uint32_t *const SHPR3 = (uint32_t *const)0xE000ED20;
static void
chx_prio_init (void)
{
*AIRCR = 0x05FA0000 | ( 5 << 8); /* PRIGROUP = 5, 2-bit:2-bit. */
*SHPR2 = (CPU_EXCEPTION_PRIORITY_SVC << 24);
*SHPR3 = ((CPU_EXCEPTION_PRIORITY_SYSTICK << 24)
| (CPU_EXCEPTION_PRIORITY_PENDSV << 16));
}
/**
* chx_fatal - Fatal error point.
* @err_code: Error code
*
* When it detects a coding error, this function will be called to
* stop further execution of code. It never returns.
*/
void
chx_fatal (uint32_t err_code)
{
(void)err_code;
for (;;);
}
/* RUNNING: the current thread. */
struct chx_thread *running;
/* Double linked list operations. */
struct chx_dll {
struct chx_thread *next, *prev;
};
struct chx_queue {
struct chx_thread *next, *prev;
struct chx_spinlock lock;
};
/* READY: priority queue. */
static struct chx_queue q_ready;
/* Queue of threads waiting for timer. */
static struct chx_queue q_timer;
/* Queue of threads which have been exited. */
static struct chx_queue q_exit;
/* Queue of threads which wait exit of some thread. */
static struct chx_queue q_join;
/* Forward declaration(s). */
static void chx_request_preemption (uint16_t prio);
static void chx_timer_dequeue (struct chx_thread *tp);
static void chx_timer_insert (struct chx_thread *tp, uint32_t usec);
/**************/
static void chx_spin_lock (struct chx_spinlock *lk)
{
(void)lk;
}
static void chx_spin_unlock (struct chx_spinlock *lk)
{
(void)lk;
}
/* The thread context: specific to ARM Cortex-M3 now. */
struct tcontext {
uint32_t reg[9]; /* r4, r5, r6, r7, r8, r9, r10, r11, r13 */
};
/* Saved registers on the stack. */
struct chx_stack_regs {
uint32_t reg[8]; /* r0, r1, r2, r3, r12, lr, pc, xpsr */
};
/*
* Constants for ARM.
*/
#define REG_EXIT 4 /* R8 */
#define REG_SP 8
#define REG_R0 0
#define REG_LR 5
#define REG_PC 6
#define REG_XPSR 7
#define INITIAL_XPSR 0x01000000 /* T=1 */
/**************/
struct chx_thread {
struct chx_thread *next, *prev;
struct tcontext tc;
uint32_t state : 4;
uint32_t flag_detached : 1;
uint32_t flag_got_cancel : 1;
uint32_t flag_join_req : 1;
uint32_t flag_sched_rr : 1;
uint32_t flag_cancelable : 1;
uint32_t : 7;
uint32_t prio_orig : 8;
uint32_t prio : 8;
uint32_t v;
struct chx_mtx *mutex_list;
struct chx_cleanup *clp;
};
static void
chx_cpu_sched_lock (void)
{
if (running->prio < CHOPSTX_PRIO_INHIBIT_PREEMPTION)
{
#if defined(__ARM_ARCH_6M__)
asm volatile ("cpsid i" : : : "memory");
#else
register uint32_t tmp = CPU_EXCEPTION_PRIORITY_INHIBIT_SCHED;
asm volatile ("msr BASEPRI, %0" : : "r" (tmp) : "memory");
#endif
}
}
static void
chx_cpu_sched_unlock (void)
{
if (running->prio < CHOPSTX_PRIO_INHIBIT_PREEMPTION)
{
#if defined(__ARM_ARCH_6M__)
asm volatile ("cpsie i" : : : "memory");
#else
register uint32_t tmp = CPU_EXCEPTION_PRIORITY_CLEAR;
asm volatile ("msr BASEPRI, %0" : : "r" (tmp) : "memory");
#endif
}
}
/*
* Double linked list handling.
*/
static int
ll_empty (void *head)
{
struct chx_thread *l = (struct chx_thread *)head;
return (struct chx_thread *)l == l->next;
}
static struct chx_thread *
ll_dequeue (struct chx_thread *tp)
{
tp->next->prev = tp->prev;
tp->prev->next = tp->next;
tp->prev = tp->next = tp;
return tp;
}
static void
ll_insert (struct chx_thread *tp0, void *head)
{
struct chx_thread *tp = (struct chx_thread *)head;
tp0->next = tp;
tp0->prev = tp->prev;
tp->prev->next = tp0;
tp->prev = tp0;
}
static struct chx_thread *
ll_pop (void *head)
{
struct chx_thread *l = (struct chx_thread *)head;
struct chx_thread *tp0 = l->next;
if (tp0 == l)
return NULL;
return ll_dequeue (tp0);
}
static void
ll_prio_push (struct chx_thread *tp0, void *head)
{
struct chx_thread *l = (struct chx_thread *)head;
struct chx_thread *tp;
for (tp = l->next; tp != l; tp = tp->next)
if (tp->prio <= tp0->prio)
break;
ll_insert (tp0, tp);
}
static void
ll_prio_enqueue (struct chx_thread *tp0, void *head)
{
struct chx_thread *l = (struct chx_thread *)head;
struct chx_thread *tp;
for (tp = l->next; tp != l; tp = tp->next)
if (tp->prio < tp0->prio)
break;
ll_insert (tp0, tp);
}
/*
* Thread status.
*/
enum {
THREAD_RUNNING=0,
THREAD_READY,
THREAD_WAIT_MTX,
THREAD_WAIT_CND,
THREAD_WAIT_TIME,
THREAD_WAIT_INT,
THREAD_JOIN,
/**/
THREAD_EXITED=0x0E,
THREAD_FINISHED=0x0F
};
static struct chx_thread *
chx_ready_pop (void)
{
struct chx_thread *tp;
chx_spin_lock (&q_ready.lock);
tp = ll_pop (&q_ready);
if (tp)
tp->state = THREAD_RUNNING;
chx_spin_unlock (&q_ready.lock);
return tp;
}
static void
chx_ready_push (struct chx_thread *tp)
{
chx_spin_lock (&q_ready.lock);
tp->state = THREAD_READY;
ll_prio_push (tp, &q_ready);
chx_spin_unlock (&q_ready.lock);
}
static void
chx_ready_enqueue (struct chx_thread *tp)
{
chx_spin_lock (&q_ready.lock);
tp->state = THREAD_READY;
ll_prio_enqueue (tp, &q_ready);
chx_spin_unlock (&q_ready.lock);
}
static void __attribute__((naked, used))
idle (void)
{
#if defined(USE_WFI_FOR_IDLE)
for (;;)
asm volatile ("wfi" : : : "memory");
#else
for (;;);
#endif
}
static void
chx_set_timer (struct chx_thread *q, uint32_t ticks)
{
if (q == (struct chx_thread *)&q_timer)
chx_systick_reload (ticks);
else
q->v = ticks;
}
static void
chx_timer_insert (struct chx_thread *tp, uint32_t usec)
{
struct chx_thread *q;
uint32_t ticks = usec_to_ticks (usec);
uint32_t next_ticks = chx_systick_get ();
for (q = q_timer.next; q != (struct chx_thread *)&q_timer; q = q->next)
{
if (ticks < next_ticks)
{
ll_insert (tp, q);
chx_set_timer (tp->prev, ticks);
chx_set_timer (tp, (next_ticks - ticks));
break;
}
else
{
ticks -= next_ticks;
next_ticks = q->v;
}
}
if (q == (struct chx_thread *)&q_timer)
{
ll_insert (tp, q);
chx_set_timer (tp->prev, ticks);
chx_set_timer (tp, 1); /* Non-zero for the last entry. */
}
}
static void
chx_timer_dequeue (struct chx_thread *tp)
{
struct chx_thread *tp_prev;
chx_spin_lock (&q_timer.lock);
tp_prev = tp->prev;
if (tp_prev == (struct chx_thread *)&q_timer)
{
if (tp->next == (struct chx_thread *)&q_timer)
chx_set_timer (tp_prev, 0); /* Cancel timer*/
else
{ /* Update timer. */
uint32_t next_ticks = chx_systick_get () + tp->v;
chx_set_timer (tp_prev, next_ticks);
}
}
else
tp_prev->v += tp->v;
ll_dequeue (tp);
tp->v = 0;
chx_spin_unlock (&q_timer.lock);
}
void
chx_timer_expired (void)
{
struct chx_thread *tp;
uint16_t prio = 0; /* Use uint16_t here. */
chx_spin_lock (&q_timer.lock);
if ((tp = ll_pop (&q_timer)))
{
uint32_t next_tick = tp->v;
chx_ready_enqueue (tp);
if (tp == running) /* tp->flag_sched_rr == 1 */
prio = MAX_PRIO;
else
if ((uint16_t)tp->prio > prio)
prio = (uint16_t)tp->prio;
if (!ll_empty (&q_timer))
{
struct chx_thread *tp_next;
for (tp = q_timer.next;
tp != (struct chx_thread *)&q_timer && next_tick == 0;
tp = tp_next)
{
next_tick = tp->v;
tp_next = tp->next;
ll_dequeue (tp);
chx_ready_enqueue (tp);
if (tp == running)
prio = MAX_PRIO;
else
if ((uint16_t)tp->prio > prio)
prio = (uint16_t)tp->prio;
}
if (!ll_empty (&q_timer))
chx_set_timer ((struct chx_thread *)&q_timer, next_tick);
}
}
chx_request_preemption (prio);
chx_spin_unlock (&q_timer.lock);
}
static chopstx_intr_t *intr_top;
static struct chx_spinlock intr_lock;
void
chx_handle_intr (void)
{
chopstx_intr_t *intr;
register uint32_t irq_num;
asm volatile ("mrs %0, IPSR\n\t"
"sub %0, #16" /* Exception # - 16 = interrupt number. */
: "=r" (irq_num) : /* no input */ : "memory");
chx_disable_intr (irq_num);
chx_spin_lock (&intr_lock);
for (intr = intr_top; intr; intr = intr->next)
if (intr->irq_num == irq_num)
break;
if (intr)
{
intr->ready++;
if (intr->tp != running && intr->tp->state == THREAD_WAIT_INT)
{
chx_ready_enqueue (intr->tp);
chx_request_preemption (intr->tp->prio);
}
}
chx_spin_unlock (&intr_lock);
}
void
chx_systick_init (void)
{
chx_systick_reset ();
if ((CHX_FLAGS_MAIN & CHOPSTX_SCHED_RR))
{
chx_cpu_sched_lock ();
chx_spin_lock (&q_timer.lock);
chx_timer_insert (running, PREEMPTION_USEC);
chx_spin_unlock (&q_timer.lock);
chx_cpu_sched_unlock ();
}
}
chopstx_t chopstx_main;
void
chx_init (struct chx_thread *tp)
{
chx_prio_init ();
memset (&tp->tc, 0, sizeof (tp->tc));
q_ready.next = q_ready.prev = (struct chx_thread *)&q_ready;
q_timer.next = q_timer.prev = (struct chx_thread *)&q_timer;
q_exit.next = q_exit.prev = (struct chx_thread *)&q_exit;
q_join.next = q_join.prev = (struct chx_thread *)&q_join;
tp->next = tp->prev = tp;
tp->mutex_list = NULL;
tp->clp = NULL;
tp->state = THREAD_RUNNING;
tp->flag_got_cancel = tp->flag_join_req = tp->flag_cancelable = 0;
tp->flag_sched_rr = (CHX_FLAGS_MAIN & CHOPSTX_SCHED_RR)? 1 : 0;
tp->flag_detached = (CHX_FLAGS_MAIN & CHOPSTX_DETACHED)? 1 : 0;
tp->prio_orig = CHX_PRIO_MAIN_INIT;
tp->prio = 0;
tp->v = 0;
running = tp;
if (CHX_PRIO_MAIN_INIT >= CHOPSTX_PRIO_INHIBIT_PREEMPTION)
chx_cpu_sched_lock ();
tp->prio = CHX_PRIO_MAIN_INIT;
chopstx_main = (chopstx_t)tp;
}
/**
* chopstx_main_init - initialize main thread
* @prio: priority
*
* Initialize main thread with @prio.
* The thread main is created with priority CHX_PRIO_MAIN_INIT,
* and it runs with that priority until this routine will is called.
*/
void
chopstx_main_init (chopstx_prio_t prio)
{
struct chx_thread *tp = (struct chx_thread *)chopstx_main;
tp->prio_orig = prio;
if (prio >= CHOPSTX_PRIO_INHIBIT_PREEMPTION)
chx_cpu_sched_lock ();
tp->prio = prio;
}
static void
chx_request_preemption (uint16_t prio)
{
if (running == NULL || (uint16_t)running->prio < prio)
{
*ICSR = (1 << 28);
asm volatile ("" : : : "memory");
}
}
#define CHX_SLEEP 0
#define CHX_YIELD 1
static void
chx_sched (uint32_t arg)
{
register uint32_t r0 asm ("r0") = arg;
asm volatile ("svc #0" : : "r" (r0): "memory");
}
/* The RETVAL is saved into register R8. */
static void __attribute__((noreturn))
chx_exit (void *retval)
{
register uint32_t r8 asm ("r8");
struct chx_thread *q;
asm volatile ("mov %0, %1" : "=r" (r8) : "r" (retval));
chx_cpu_sched_lock ();
if (running->flag_join_req)
{ /* wake up a thread which requests to join */
chx_spin_lock (&q_join.lock);
for (q = q_join.next; q != (struct chx_thread *)&q_join; q = q->next)
if (q->v == (uint32_t)running)
{ /* should be one at most. */
ll_dequeue (q);
chx_ready_enqueue (q);
break;
}
chx_spin_unlock (&q_join.lock);
}
if (running->flag_sched_rr)
chx_timer_dequeue (running);
chx_spin_lock (&q_exit.lock);
ll_insert (running, &q_exit);
if (running->flag_detached)
running->state = THREAD_FINISHED;
else
running->state = THREAD_EXITED;
chx_spin_unlock (&q_exit.lock);
asm volatile ("" : : "r" (r8) : "memory");
chx_sched (CHX_SLEEP);
/* never comes here. */
for (;;);
}
static chopstx_prio_t
chx_mutex_unlock (chopstx_mutex_t *mutex)
{
struct chx_thread *tp;
chopstx_prio_t prio = 0;
mutex->owner = NULL;
running->mutex_list = mutex->list;
mutex->list = NULL;
tp = ll_pop (&mutex->q);
if (tp)
{
uint16_t newprio = running->prio_orig;
chopstx_mutex_t *m;
chx_ready_enqueue (tp);
/* Examine mutexes we hold, and determine new priority for running. */
for (m = running->mutex_list; m; m = m->list)
if (!ll_empty (&m->q) && m->q.next->prio > newprio)
newprio = m->q.next->prio;
/* Then, assign it. */
running->prio = newprio;
if (prio < tp->prio)
prio = tp->prio;
}
return prio;
}
#define CHOPSTX_PRIO_MASK ((1 << CHOPSTX_PRIO_BITS) - 1)
typedef void *(voidfunc) (void *);
extern void cause_link_time_error_unexpected_size_of_struct_chx_thread (void);
/**
* chopstx_create - Create a thread
* @flags_and_prio: Flags and priority
* @stack_addr: Stack address
* @stack_size: Size of stack
* @thread_entry: Entry function of new thread
* @arg: Argument to the thread entry function
*
* Create a thread. Returns thread ID.
*/
chopstx_t
chopstx_create (uint32_t flags_and_prio,
uint32_t stack_addr, size_t stack_size,
voidfunc thread_entry, void *arg)
{
struct chx_thread *tp;
void *stack;
struct chx_stack_regs *p;
chopstx_prio_t prio = (flags_and_prio & CHOPSTX_PRIO_MASK);
if (CHOPSTX_THREAD_SIZE != sizeof(struct chx_thread))
cause_link_time_error_unexpected_size_of_struct_chx_thread ();
if (stack_size < sizeof (struct chx_thread) + 8 * sizeof (uint32_t))
chx_fatal (CHOPSTX_ERR_THREAD_CREATE);
stack = (void *)(stack_addr + stack_size - sizeof (struct chx_thread)
- sizeof (struct chx_stack_regs));
memset (stack, 0, sizeof (struct chx_stack_regs));
tp = (struct chx_thread *)(stack + sizeof (struct chx_stack_regs));
p = (struct chx_stack_regs *)stack;
p->reg[REG_R0] = (uint32_t)arg;
p->reg[REG_LR] = (uint32_t)chopstx_exit;
p->reg[REG_PC] = (uint32_t)thread_entry;
p->reg[REG_XPSR] = INITIAL_XPSR;
memset (&tp->tc, 0, sizeof (tp->tc));
tp->tc.reg[REG_SP] = (uint32_t)stack;
tp->next = tp->prev = tp;
tp->mutex_list = NULL;
tp->clp = NULL;
tp->state = THREAD_EXITED;
tp->flag_got_cancel = tp->flag_join_req = tp->flag_cancelable = 0;
tp->flag_sched_rr = (flags_and_prio & CHOPSTX_SCHED_RR)? 1 : 0;
tp->flag_detached = (flags_and_prio & CHOPSTX_DETACHED)? 1 : 0;
tp->prio_orig = tp->prio = prio;
tp->v = 0;
chx_cpu_sched_lock ();
chx_ready_enqueue (tp);
if (tp->prio > running->prio)
chx_sched (CHX_YIELD);
else
chx_cpu_sched_unlock ();
return (chopstx_t)tp;
}
/**
* chopstx_usec_wait_var - Sleep for micro seconds (specified by variable)
* @var: Pointer to usec
*
* Sleep for micro seconds, specified by @var.
* Another thread can clear @var to stop the caller going into sleep.
*/
void
chopstx_usec_wait_var (uint32_t *var)
{
register uint32_t *r8 asm ("r8");
uint32_t *usec_p = var;
uint32_t usec;
uint32_t usec0 = 0;
asm volatile ("mov %0, %1" : "=r" (r8) : "r" (usec_p));
while (1)
{
chopstx_testcancel ();
chx_cpu_sched_lock ();
if (!r8) /* awakened */
break;
*usec_p -= usec0;
usec = *usec_p;
if (usec == 0)
break;
usec0 = (usec > 200*1000) ? 200*1000: usec;
if (running->flag_sched_rr)
chx_timer_dequeue (running);
chx_spin_lock (&q_timer.lock);
running->state = THREAD_WAIT_TIME;
chx_timer_insert (running, usec0);
chx_spin_unlock (&q_timer.lock);
asm volatile ("mov %0, %1" : "=r" (r8) : "r" (usec_p));
chx_sched (CHX_SLEEP);
asm ("" : "=r" (r8) : "r" (r8));
}
chx_cpu_sched_unlock ();
}
/**
* chopstx_usec_wait - Sleep for micro seconds
* @usec: number of micro seconds
*
* Sleep for @usec.
*/
void
chopstx_usec_wait (uint32_t usec)
{
chopstx_usec_wait_var (&usec);
}
/**
* chopstx_mutex_init - Initialize the mutex
* @mutex: Mutex
*
* Initialize @mutex.
*/
void
chopstx_mutex_init (chopstx_mutex_t *mutex)
{
mutex->q.next = mutex->q.prev = (struct chx_thread *)mutex;
mutex->list = NULL;
}
/**
* chopstx_mutex_lock - Lock the mutex
* @mutex: Mutex
*
* Lock @mutex.
*/
void
chopstx_mutex_lock (chopstx_mutex_t *mutex)
{
struct chx_thread *tp = running;
while (1)
{
chopstx_mutex_t *m = mutex;
struct chx_thread *owner;
chx_cpu_sched_lock ();
chx_spin_lock (&m->lock);
if (m->owner == NULL)
{
/* The mutex is acquired. */
m->owner = tp;
m->list = tp->mutex_list;
tp->mutex_list = m;
chx_spin_unlock (&m->lock);
chx_cpu_sched_unlock ();
break;
}
owner = m->owner;
while (1)
{ /* Priority inheritance. */
owner->prio = tp->prio;
if (owner->state == THREAD_READY)
{
ll_prio_enqueue (ll_dequeue (owner), &q_ready);
break;
}
else if (owner->state == THREAD_WAIT_MTX)
{
m = (chopstx_mutex_t *)owner->v;
ll_prio_enqueue (ll_dequeue (owner), m);
owner = m->owner;
continue;
}
else if (owner->state == THREAD_WAIT_CND)
{
chopstx_cond_t *cnd = (chopstx_cond_t *)owner->v;
ll_prio_enqueue (ll_dequeue (owner), cnd);
break;
}
else
break;
/* Assume it's UP no case of: ->state==RUNNING on SMP??? */
}
if (tp->flag_sched_rr)
chx_timer_dequeue (tp);
ll_prio_enqueue (tp, &mutex->q);
tp->state = THREAD_WAIT_MTX;
tp->v = (uint32_t)mutex;
chx_spin_unlock (&mutex->lock);
chx_sched (CHX_SLEEP);
}
return;
}
/**
* chopstx_mutex_unlock - Unlock the mutex
* @mutex: Mutex
*
* Unlock @mutex.
*/
void
chopstx_mutex_unlock (chopstx_mutex_t *mutex)
{
chopstx_prio_t prio;
chx_cpu_sched_lock ();
chx_spin_lock (&mutex->lock);
prio = chx_mutex_unlock (mutex);
chx_spin_unlock (&mutex->lock);
if (prio > running->prio)
chx_sched (CHX_YIELD);
else
chx_cpu_sched_unlock ();
}
/**
* chopstx_cond_init - Initialize the condition variable
* @cond: Condition variable
*
* Initialize @cond.
*/
void
chopstx_cond_init (chopstx_cond_t *cond)
{
cond->q.next = cond->q.prev = (struct chx_thread *)cond;
}
/**
* chopstx_cond_wait - Wait on the condition variable
* @cond: Condition variable
* @mutex: Associated mutex
*
* Wait for @cond with @mutex.
*/
void
chopstx_cond_wait (chopstx_cond_t *cond, chopstx_mutex_t *mutex)
{
struct chx_thread *tp = running;
chopstx_testcancel ();
chx_cpu_sched_lock ();
if (mutex)
{
chx_spin_lock (&mutex->lock);
chx_mutex_unlock (mutex);
chx_spin_unlock (&mutex->lock);
}
if (tp->flag_sched_rr)
chx_timer_dequeue (tp);
chx_spin_lock (&cond->lock);
ll_prio_enqueue (tp, &cond->q);
tp->state = THREAD_WAIT_CND;
tp->v = (uint32_t)cond;
chx_spin_unlock (&cond->lock);
chx_sched (CHX_SLEEP);
if (mutex)
chopstx_mutex_lock (mutex);
}
/**
* chopstx_cond_signal - Wake up a thread waiting on the condition variable
* @cond: Condition variable
*
* Wake up a thread waiting on @cond.
*/
void
chopstx_cond_signal (chopstx_cond_t *cond)
{
struct chx_thread *tp;
int yield = 0;
chx_cpu_sched_lock ();
chx_spin_lock (&cond->lock);
tp = ll_pop (&cond->q);
if (tp)
{
chx_ready_enqueue (tp);
if (tp->prio > running->prio)
yield = 1;
}
chx_spin_unlock (&cond->lock);
if (yield)
chx_sched (CHX_YIELD);
else
chx_cpu_sched_unlock ();
}
/**
* chopstx_cond_broadcast - Wake up all waiting on the condition variable
* @cond: Condition Variable
*
* Wake up all threads waiting on @cond.
*/
void
chopstx_cond_broadcast (chopstx_cond_t *cond)
{
struct chx_thread *tp;
int yield = 0;
chx_cpu_sched_lock ();
chx_spin_lock (&cond->lock);
while ((tp = ll_pop (&cond->q)))
{
chx_ready_enqueue (tp);
if (tp->prio > running->prio)
yield = 1;
}
chx_spin_unlock (&cond->lock);
if (yield)
chx_sched (CHX_YIELD);
else
chx_cpu_sched_unlock ();
}
/**
* chopstx_claim_irq - Claim interrupt request to handle by this thread
* @intr: Pointer to INTR structure
* @irq_num: IRQ Number (hardware specific)
*
* Claim interrupt @intr with @irq_num for this thread.
*/
void
chopstx_claim_irq (chopstx_intr_t *intr, uint8_t irq_num)
{
intr->irq_num = irq_num;
intr->tp = running;
intr->ready = 0;
chx_cpu_sched_lock ();
chx_disable_intr (irq_num);
chx_set_intr_prio (irq_num);
chx_spin_lock (&intr_lock);
intr->next = intr_top;
intr_top = intr;
chx_spin_unlock (&intr_lock);
chx_cpu_sched_unlock ();
}
/**
* chopstx_realease_irq - Unregister interrupt request
* @intr0: Interrupt request to be unregistered
*
* Release the interrupt request specified by @intr0.
*/
void
chopstx_release_irq (chopstx_intr_t *intr0)
{
chopstx_intr_t *intr, *intr_prev;
chx_cpu_sched_lock ();
chx_enable_intr (intr0->irq_num);
chx_spin_lock (&intr_lock);
intr_prev = intr_top;
for (intr = intr_top; intr; intr = intr->next)
if (intr == intr0)
break;
if (intr == intr_top)
intr_top = intr_top->next;
else
intr_prev->next = intr->next;
chx_spin_unlock (&intr_lock);
chx_cpu_sched_unlock ();
}
static void
chx_release_irq_thread (struct chx_thread *tp)
{
chopstx_intr_t *intr, *intr_prev;
chx_cpu_sched_lock ();
chx_spin_lock (&intr_lock);
intr_prev = intr_top;
for (intr = intr_top; intr; intr = intr->next)
if (intr->tp == tp)
break;
if (intr)
{
chx_enable_intr (intr->irq_num);
if (intr == intr_top)
intr_top = intr_top->next;
else
intr_prev->next = intr->next;
}
chx_spin_unlock (&intr_lock);
chx_cpu_sched_unlock ();
}
/**
* chopstx_intr_wait - Wait for interrupt request from hardware
* @intr: Pointer to INTR structure
*
* Wait for the interrupt @intr to be occured.
*/
void
chopstx_intr_wait (chopstx_intr_t *intr)
{
chopstx_testcancel ();
chx_cpu_sched_lock ();
if (intr->ready == 0)
{
chx_enable_intr (intr->irq_num);
if (running->flag_sched_rr)
chx_timer_dequeue (running);
running->state = THREAD_WAIT_INT;
running->v = 0;
chx_sched (CHX_SLEEP);
chx_clr_intr (intr->irq_num);
}
else
chx_cpu_sched_unlock ();
intr->ready--;
}
/**
* chopstx_cleanup_push - Register a clean-up
* @clp: Pointer to clean-up structure
*
* Register a clean-up structure.
*/
void
chopstx_cleanup_push (struct chx_cleanup *clp)
{
clp->next = running->clp;
running->clp = clp;
}
/**
* chopstx_cleanup_pop - Release a clean-up
* @execute: Execute the clen-up function on release
*
* Unregister a clean-up structure. When @execute is non-zero, the
* clean-up will be executed.
*/
void
chopstx_cleanup_pop (int execute)
{
struct chx_cleanup *clp = running->clp;
if (clp)
{
running->clp = clp->next;
if (execute)
clp->routine (clp->arg);
}
}
/**
* chopstx_exit - Terminate the execution of thread
* @retval: Return value (to be caught by a joining thread)
*
* Calling this function terminates the execution of thread, after
* calling clean up functions. If the calling thread still holds
* mutexes, they will be released. If the calling thread claiming
* IRQ, it will be released, too. This function never returns.
*/
void
chopstx_exit (void *retval)
{
struct chx_mtx *m, *m_next;
struct chx_cleanup *clp = running->clp;
running->clp = NULL;
while (clp)
{
clp->routine (clp->arg);
clp = clp->next;
}
/* Release all mutexes this thread still holds. */
for (m = running->mutex_list; m; m = m_next)
{
m_next = m->list;
chx_cpu_sched_lock ();
chx_spin_lock (&m->lock);
chx_mutex_unlock (m);
chx_spin_unlock (&m->lock);
chx_cpu_sched_unlock ();
}
chx_release_irq_thread (running);
chx_exit (retval);
}
/**
* chopstx_join - join with a terminated thread
* @thd: Thread to wait
* @ret: Pointer to void * to store return value
*
* Waits for the thread of @thd to terminate.
*/
void
chopstx_join (chopstx_t thd, void **ret)
{
struct chx_thread *tp = (struct chx_thread *)thd;
/*
* We don't offer deadlock detection. It's users' responsibility.
*/
chx_cpu_sched_lock ();
if (tp->flag_detached)
{
chx_cpu_sched_unlock ();
chx_fatal (CHOPSTX_ERR_JOIN);
}
if (tp->state != THREAD_EXITED)
{
if (running->flag_sched_rr)
chx_timer_dequeue (running);
chx_spin_lock (&q_join.lock);
ll_insert (running, &q_join);
running->v = (uint32_t)tp;
running->state = THREAD_JOIN;
chx_spin_unlock (&q_join.lock);
tp->flag_join_req = 1;
if (tp->prio < running->prio)
{
tp->prio = running->prio;
/*XXX: dequeue and enqueue with new prio. */
}
chx_sched (CHX_SLEEP);
}
else
chx_cpu_sched_unlock ();
tp->state = THREAD_FINISHED;
if (ret)
*ret = (void *)tp->tc.reg[REG_EXIT]; /* R8 */
}
/**
* chopstx_wakeup_usec_wait - wakeup the sleeping thread for timer
* @thd: Thread to be awakened
*
* Canceling the timer, wake up the sleeping thread.
* No return value.
*/
void
chopstx_wakeup_usec_wait (chopstx_t thd)
{
struct chx_thread *tp = (struct chx_thread *)thd;
int yield = 0;
chx_cpu_sched_lock ();
if (tp->state == THREAD_WAIT_TIME)
{
tp->tc.reg[REG_EXIT] = 0;
chx_timer_dequeue (tp);
chx_ready_enqueue (tp);
if (tp->prio > running->prio)
yield = 1;
}
if (yield)
chx_sched (CHX_YIELD);
else
chx_cpu_sched_unlock ();
}
/**
* chopstx_cancel - request a cancellation to a thread
* @thd: Thread to be canceled
*
* This function requests a cancellation of a thread @thd.
* No return value.
*/
void
chopstx_cancel (chopstx_t thd)
{
struct chx_thread *tp = (struct chx_thread *)thd;
struct chx_stack_regs *p;
int yield = 0;
/* Assume it's UP, it's *never*: tp->state==RUNNING on SMP??? */
chx_cpu_sched_lock ();
tp->flag_got_cancel = 1;
if (!tp->flag_cancelable)
{
chx_cpu_sched_unlock ();
return;
}
/* Cancellation points: cond_wait, intr_wait, and usec_wait. */
if (tp->state == THREAD_WAIT_CND || tp->state == THREAD_WAIT_INT
|| tp->state == THREAD_WAIT_TIME)
{
/* Throw away registers on stack and direct to chopstx_exit. */
/* This is pretty much violent, but it works. */
p = (struct chx_stack_regs *)tp->tc.reg[REG_SP];
p->reg[REG_R0] = CHOPSTX_EXIT_CANCELED;
p->reg[REG_PC] = (uint32_t)chopstx_exit;
if (tp->state == THREAD_WAIT_CND)
ll_dequeue (tp);
else if (tp->state == THREAD_WAIT_TIME)
chx_timer_dequeue (tp);
chx_ready_enqueue (tp);
if (tp->prio > running->prio)
yield = 1;
}
if (yield)
chx_sched (CHX_YIELD);
else
chx_cpu_sched_unlock ();
}
/**
* chopstx_testcancel - catch pending cancellation request
*
* Calling chopstx_testcancel creates a cancellation point.
* No return value. If the thread is canceled, this function
* does not return.
*/
void
chopstx_testcancel (void)
{
if (running->flag_cancelable && running->flag_got_cancel)
chopstx_exit ((void *)CHOPSTX_EXIT_CANCELED_IN_SYNC);
}
/**
* chopstx_setcancelstate - set cancelability state
* @cancel_disable: 0 to enable cancelation, otherwise disabled.
*
* Calling chopstx_setcancelstate sets cancelability state.
*
* Returns old state which is 0 when it was enabled.
*/
int
chopstx_setcancelstate (int cancel_disable)
{
int old_state = !running->flag_cancelable;
running->flag_cancelable = (cancel_disable == 0);
chopstx_testcancel ();
return old_state;
}
/*
* Lower layer architecture specific exception handling entries.
*
*/
/* Registers on stack (PSP): r0, r1, r2, r3, r12, lr, pc, xpsr */
static void __attribute__ ((naked, used))
sched (void)
{
register struct chx_thread *tp asm ("r0");
tp = chx_ready_pop ();
if (tp && tp->flag_sched_rr)
{
chx_spin_lock (&q_timer.lock);
chx_timer_insert (tp, PREEMPTION_USEC);
chx_spin_unlock (&q_timer.lock);
}
asm volatile (/* Now, r0 points to the thread to be switched. */
/* Put it to *running. */
"ldr r1, =running\n\t"
/* Update running. */
"str r0, [r1]\n\t"
#if defined(__ARM_ARCH_6M__)
"cmp r0, #0\n\t"
"beq 1f\n\t"
#else
"cbz r0, 1f\n\t"
#endif
/**/
"add r0, #8\n\t"
"ldm r0!, {r4, r5, r6, r7}\n\t"
#if defined(__ARM_ARCH_6M__)
"ldm r0!, {r1, r2, r3}\n\t"
"mov r8, r1\n\t"
"mov r9, r2\n\t"
"mov r10, r3\n\t"
"ldm r0!, {r1, r2}\n\t"
"mov r11, r1\n\t"
"msr PSP, r2\n\t"
#else
"ldr r8, [r0], #4\n\t"
"ldr r9, [r0], #4\n\t"
"ldr r10, [r0], #4\n\t"
"ldr r11, [r0], #4\n\t"
"ldr r1, [r0], #4\n\t"
"msr PSP, r1\n\t"
#endif
"ldrb r1, [r0, #3]\n\t" /* ->PRIO field. */
"cmp r1, #247\n\t"
"bhi 0f\n\t" /* Leave interrupt disabled if >= 248 */
/**/
/* Unmask interrupts. */
"mov r0, #0\n\t"
#if defined(__ARM_ARCH_6M__)
"cpsie i\n"
#else
"msr BASEPRI, r0\n"
#endif
/**/
"0:\n\t"
"sub r0, #3\n\t" /* EXC_RETURN to a thread with PSP */
"bx r0\n"
"1:\n\t"
/* Spawn an IDLE thread. */
"ldr r0, =__main_stack_end__\n\t"
"msr MSP, r0\n\t"
"mov r0, #0\n\t"
"mov r1, #0\n\t"
"ldr r2, =idle\n\t" /* PC = idle */
#if defined(__ARM_ARCH_6M__)
"mov r3, #0x010\n\t"
"lsl r3, r3, #20\n\t" /* xPSR = T-flag set (Thumb) */
#else
"mov r3, #0x01000000\n\t" /* xPSR = T-flag set (Thumb) */
#endif
"push {r0, r1, r2, r3}\n\t"
"mov r0, #0\n\t"
"mov r1, #0\n\t"
"mov r2, #0\n\t"
"mov r3, #0\n\t"
"push {r0, r1, r2, r3}\n"
/**/
/* Unmask interrupts. */
"mov r0, #0\n\t"
#if defined(__ARM_ARCH_6M__)
"cpsie i\n\t"
#else
"msr BASEPRI, r0\n\t"
#endif
/**/
"sub r0, #7\n\t" /* EXC_RETURN to a thread with MSP */
"bx r0\n"
: /* no output */ : "r" (tp) : "memory");
}
void __attribute__ ((naked))
preempt (void)
{
register struct chx_thread *tp asm ("r0");
tp = (struct chx_thread *)CPU_EXCEPTION_PRIORITY_INHIBIT_SCHED;
asm (
#if defined(__ARM_ARCH_6M__)
"cpsid i\n\t"
#else
"msr BASEPRI, r0\n\t"
#endif
"ldr r1, =running\n\t"
"ldr r0, [r1]\n\t"
#if defined(__ARM_ARCH_6M__)
"cmp r0, #0\n\t"
"bne 0f\n\t"
#else
"cbnz r0, 0f\n\t"
#endif
/* It's idle which was preempted. Discard saved registers on stack. */
"ldr r1, =__main_stack_end__\n\t"
"msr MSP, r1\n\t"
"b sched\n"
"0:\n\t"
#if defined(__ARM_ARCH_6M__)
"add r1, r0, #4\n\t"
"add r1, #4\n\t"
#else
"add r1, r0, #8\n\t"
#endif
/* Save registers onto CHX_THREAD struct. */
"stm r1!, {r4, r5, r6, r7}\n\t"
"mov r2, r8\n\t"
"mov r3, r9\n\t"
"mov r4, r10\n\t"
"mov r5, r11\n\t"
"mrs r6, PSP\n\t" /* r13(=SP) in user space. */
"stm r1!, {r2, r3, r4, r5, r6}"
: "=r" (tp)
: "r" (tp)
: "r1", "r2", "r3", "r4", "r5", "r6", "cc", "memory");
if (tp)
{
if (tp->flag_sched_rr)
{
if (tp->state == THREAD_RUNNING)
{
chx_timer_dequeue (tp);
chx_ready_enqueue (tp);
}
/*
* It may be THREAD_READY after chx_timer_expired.
* Then, do nothing.
*/
}
else
chx_ready_push (tp);
running = NULL;
}
asm volatile ("b sched"
: /* no output */: /* no input */ : "memory");
}
/*
* System call: switch to another thread.
* There are two cases:
* ORIG_R0=0 (SLEEP): Current RUNNING thread is already connected to
* something (mutex, cond, intr, etc.)
* ORIG_R0=1 (YIELD): Current RUNNING thread is active,
* it is needed to be enqueued to READY queue.
*/
void __attribute__ ((naked))
svc (void)
{
register struct chx_thread *tp asm ("r0");
register uint32_t orig_r0 asm ("r1");
asm ("ldr r1, =running\n\t"
"ldr r0, [r1]\n\t"
#if defined(__ARM_ARCH_6M__)
"add r1, r0, #4\n\t"
"add r1, #4\n\t"
#else
"add r1, r0, #8\n\t"
#endif
/* Save registers onto CHX_THREAD struct. */
"stm r1!, {r4, r5, r6, r7}\n\t"
"mov r2, r8\n\t"
"mov r3, r9\n\t"
"mov r4, r10\n\t"
"mov r5, r11\n\t"
"mrs r6, PSP\n\t" /* r13(=SP) in user space. */
"stm r1!, {r2, r3, r4, r5, r6}\n\t"
"ldr r1, [r6]"
: "=r" (tp), "=r" (orig_r0)
: /* no input */
: "r2", "r3", "r4", "r5", "r6", "memory");
if (orig_r0) /* yield */
{
if (tp->flag_sched_rr)
chx_timer_dequeue (tp);
chx_ready_enqueue (tp);
running = NULL;
}
asm volatile ("b sched"
: /* no output */: /* no input */ : "memory");
}