nuclear@51: #include <stdio.h>
nuclear@55: #include <assert.h>
nuclear@51: #include "sched.h"
nuclear@51: #include "proc.h"
nuclear@51: #include "intr.h"
nuclear@51: #include "asmops.h"
nuclear@51: #include "config.h"
nuclear@51: 
nuclear@55: #define EMPTY(q)	((q)->head == 0)
nuclear@51: 
nuclear@51: struct proc_list {
nuclear@51: 	struct process *head, *tail;
nuclear@51: };
nuclear@51: 
nuclear@55: static void idle_proc(void);
nuclear@55: static void ins_back(struct proc_list *list, struct process *proc);
nuclear@55: static void ins_front(struct proc_list *list, struct process *proc);
nuclear@55: static void remove(struct proc_list *list, struct process *proc);
nuclear@55: static int hash_addr(void *addr);
nuclear@51: 
nuclear@51: static struct proc_list runq;
nuclear@51: static struct proc_list zombieq;
nuclear@51: 
nuclear@55: #define HTBL_SIZE	101
nuclear@55: static struct proc_list wait_htable[HTBL_SIZE];
nuclear@55: 
nuclear@55: 
nuclear@51: void schedule(void)
nuclear@51: {
nuclear@52: 	disable_intr();
nuclear@52: 
nuclear@55: 	if(EMPTY(&runq)) {
nuclear@56: 		if(!get_current_proc()) {
nuclear@56: 			/* we're already in the idle process, don't reenter it
nuclear@56: 			 * or you'll fill up the stack very quickly.
nuclear@56: 			 */
nuclear@56: 			return;
nuclear@56: 		}
nuclear@56: 
nuclear@55: 		idle_proc();
nuclear@56: 		return;
nuclear@51: 	}
nuclear@51: 
nuclear@51: 	/* if the current process exhausted its timeslice,
nuclear@51: 	 * move it to the back of the queue.
nuclear@51: 	 */
nuclear@51: 	if(runq.head->ticks_left <= 0) {
nuclear@51: 		if(runq.head->next) {
nuclear@51: 			struct process *proc = runq.head;
nuclear@51: 			remove(&runq, proc);
nuclear@51: 			ins_back(&runq, proc);
nuclear@51: 		}
nuclear@51: 
nuclear@51: 		/* start a new timeslice */
nuclear@51: 		runq.head->ticks_left = TIMESLICE_TICKS;
nuclear@51: 	}
nuclear@51: 
nuclear@55: 	/* always enter context_switch with interrupts disabled */
nuclear@51: 	context_switch(runq.head->id);
nuclear@51: }
nuclear@51: 
nuclear@55: void add_proc(int pid)
nuclear@51: {
nuclear@51: 	int istate;
nuclear@52: 	struct process *proc;
nuclear@51: 
nuclear@51: 	istate = get_intr_state();
nuclear@51: 	disable_intr();
nuclear@51: 
nuclear@52: 	proc = get_process(pid);
nuclear@52: 
nuclear@51: 	ins_back(&runq, proc);
nuclear@53: 	proc->state = STATE_RUNNABLE;
nuclear@51: 
nuclear@51: 	set_intr_state(istate);
nuclear@51: }
nuclear@51: 
nuclear@55: /* block the process until we get a wakeup call for address ev */
nuclear@55: void wait(void *wait_addr)
nuclear@55: {
nuclear@55: 	struct process *p;
nuclear@55: 	int hash_idx;
nuclear@51: 
nuclear@55: 	disable_intr();
nuclear@55: 
nuclear@55: 	p = get_current_proc();
nuclear@55: 	assert(p);
nuclear@55: 
nuclear@55: 	/* remove it from the runqueue ... */
nuclear@55: 	remove(&runq, p);
nuclear@55: 
nuclear@55: 	/* and place it in the wait hash table based on sleep_addr */
nuclear@55: 	hash_idx = hash_addr(wait_addr);
nuclear@55: 	ins_back(wait_htable + hash_idx, p);
nuclear@55: 
nuclear@55: 	p->state = STATE_BLOCKED;
nuclear@55: 	p->wait_addr = wait_addr;
nuclear@56: 
nuclear@56: 	/* call the scheduler to give time to another process */
nuclear@56: 	schedule();
nuclear@55: }
nuclear@55: 
nuclear@55: /* wake up all the processes sleeping on this address */
nuclear@55: void wakeup(void *wait_addr)
nuclear@51: {
nuclear@55: 	int hash_idx;
nuclear@55: 	struct process *iter;
nuclear@55: 	struct proc_list *list;
nuclear@55: 
nuclear@55: 	hash_idx = hash_addr(wait_addr);
nuclear@55: 	list = wait_htable + hash_idx;
nuclear@55: 
nuclear@55: 	iter = list->head;
nuclear@55: 	while(iter) {
nuclear@55: 		if(iter->wait_addr == wait_addr) {
nuclear@55: 			/* found one, remove it, and make it runnable */
nuclear@55: 			struct process *p = iter;
nuclear@55: 			iter = iter->next;
nuclear@55: 
nuclear@55: 			remove(list, p);
nuclear@55: 			p->state = STATE_RUNNABLE;
nuclear@55: 			ins_back(&runq, p);
nuclear@55: 		} else {
nuclear@55: 			iter = iter->next;
nuclear@55: 		}
nuclear@55: 	}
nuclear@55: }
nuclear@55: 
nuclear@55: static void idle_proc(void)
nuclear@55: {
nuclear@55: 	/* make sure we send any pending EOIs if needed.
nuclear@55: 	 * end_of_irq will actually check if it's needed first.
nuclear@55: 	 */
nuclear@55: 	struct intr_frame *ifrm = get_intr_frame();
nuclear@55: 	end_of_irq(INTR_TO_IRQ(ifrm->inum));
nuclear@55: 
nuclear@56: 	set_current_pid(0);
nuclear@56: 
nuclear@55: 	/* make sure interrupts are enabled before halting */
nuclear@56: 	while(EMPTY(&runq)) {
nuclear@56: 		enable_intr();
nuclear@56: 		halt_cpu();
nuclear@56: 		disable_intr();
nuclear@56: 	}
nuclear@55: }
nuclear@55: 
nuclear@55: 
nuclear@55: /* list operations */
nuclear@55: static void ins_back(struct proc_list *list, struct process *proc)
nuclear@55: {
nuclear@55: 	if(EMPTY(list)) {
nuclear@55: 		list->head = proc;
nuclear@51: 	} else {
nuclear@55: 		list->tail->next = proc;
nuclear@51: 	}
nuclear@51: 
nuclear@51: 	proc->next = 0;
nuclear@55: 	proc->prev = list->tail;
nuclear@55: 	list->tail = proc;
nuclear@51: }
nuclear@51: 
nuclear@55: static void ins_front(struct proc_list *list, struct process *proc)
nuclear@51: {
nuclear@55: 	if(EMPTY(list)) {
nuclear@55: 		list->tail = proc;
nuclear@51: 	} else {
nuclear@55: 		list->head->prev = proc;
nuclear@51: 	}
nuclear@51: 
nuclear@55: 	proc->next = list->head;
nuclear@51: 	proc->prev = 0;
nuclear@55: 	list->head = proc;
nuclear@51: }
nuclear@51: 
nuclear@55: static void remove(struct proc_list *list, struct process *proc)
nuclear@51: {
nuclear@51: 	if(proc->prev) {
nuclear@51: 		proc->prev->next = proc->next;
nuclear@51: 	}
nuclear@51: 	if(proc->next) {
nuclear@51: 		proc->next->prev = proc->prev;
nuclear@51: 	}
nuclear@55: 	if(list->head == proc) {
nuclear@55: 		list->head = proc->next;
nuclear@51: 	}
nuclear@55: 	if(list->tail == proc) {
nuclear@55: 		list->tail = proc->prev;
nuclear@51: 	}
nuclear@51: }
nuclear@55: 
nuclear@55: static int hash_addr(void *addr)
nuclear@55: {
nuclear@55: 	return (uint32_t)addr % HTBL_SIZE;
nuclear@55: }