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/* Periodic Interval Timer Implementation for OpenPCD
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* (C) 2006 by Harald Welte <hwelte@hmw-consulting.de>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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*
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*
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* TODO: handle jiffies wrap correctly!
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*/
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#include <errno.h>
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#include <sys/types.h>
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#include <asm/system.h>
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#include <lib_AT91SAM7.h>
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#include <AT91SAM7.h>
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#include <os/pit.h>
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#include <os/dbgu.h>
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#include <os/system_irq.h>
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#include "../openpcd.h"
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/* PIT runs at MCK/16 (= 3MHz) */
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#define PIV_MS(x) (x * 3000)
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static struct timer_list *timers;
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volatile unsigned long jiffies;
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static void __timer_insert(struct timer_list *new)
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{
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struct timer_list *tl, *tl_prev = NULL;
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if (!timers) {
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/* optimize for the common, fast case */
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new->next = NULL;
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timers = new;
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return;
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}
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for (tl = timers; tl != NULL; tl = tl->next) {
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if (tl->expires < new->expires) {
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/* we need ot add just before this one */
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if (!tl_prev) {
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new->next = timers;
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timers = new;
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} else {
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new->next = tl;
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tl_prev->next = new;
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}
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}
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tl_prev = tl;
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}
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}
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static int __timer_remove(struct timer_list *old)
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{
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struct timer_list *tl, *tl_prev = NULL;
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for (tl = timers; tl != NULL; tl = tl->next) {
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if (tl == old) {
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if (tl == timers)
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timers = tl->next;
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else
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tl_prev->next = tl->next;
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return 1;
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}
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tl_prev = tl;
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}
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return 0;
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}
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int timer_del(struct timer_list *tl)
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{
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unsigned long flags;
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int ret;
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local_irq_save(flags);
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ret = __timer_remove(tl);
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local_irq_restore(flags);
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return ret;
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}
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void timer_add(struct timer_list *tl)
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{
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unsigned long flags;
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local_irq_save(flags);
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__timer_insert(tl);
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local_irq_restore(flags);
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}
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static void pit_irq(uint32_t sr)
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{
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struct timer_list *tl, *next;
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if (!(sr & 0x1))
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return;
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jiffies += *AT91C_PITC_PIVR >> 20;
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/* this is the most simple/stupid algorithm one can come up with, but
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* hey, we're on a small embedded platform with only a hand ful
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* of timers, at all */
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for (tl = timers; tl != NULL; tl = next) {
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next = tl->next;
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if (tl->expires <= jiffies) {
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/* delete timer from list */
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timer_del(tl);
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tl->function(tl->data);
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}
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}
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}
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void pit_mdelay(uint32_t ms)
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{
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uint32_t end;
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end = (AT91F_PITGetPIIR(AT91C_BASE_PITC) + ms) % 20;
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while (end < AT91F_PITGetPIIR(AT91C_BASE_PITC)) { }
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}
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void mdelay(uint32_t ms)
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{
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return pit_mdelay(ms);
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}
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void usleep(uint32_t us)
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{
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return;
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return pit_mdelay(us/1000);
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}
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void pit_init(void)
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{
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AT91F_PITC_CfgPMC();
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AT91F_PITInit(AT91C_BASE_PITC, 1000000/HZ /* uS */, 48 /* MHz */);
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sysirq_register(AT91SAM7_SYSIRQ_PIT, &pit_irq);
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AT91F_PITEnableInt(AT91C_BASE_PITC);
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}
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