100 lines
2.2 KiB
C
100 lines
2.2 KiB
C
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/*
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* m8xx_wdt.c - MPC8xx watchdog driver
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*
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* Author: Florian Schirmer <jolt@tuxbox.org>
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*
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* 2002 (c) Florian Schirmer <jolt@tuxbox.org> This file is licensed under
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* the terms of the GNU General Public License version 2. This program
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* is licensed "as is" without any warranty of any kind, whether express
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* or implied.
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*/
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#include <linux/init.h>
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#include <linux/interrupt.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <asm/8xx_immap.h>
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#include <syslib/m8xx_wdt.h>
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static int wdt_timeout;
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void m8xx_wdt_reset(void)
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{
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volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
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imap->im_siu_conf.sc_swsr = 0x556c; /* write magic1 */
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imap->im_siu_conf.sc_swsr = 0xaa39; /* write magic2 */
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}
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static irqreturn_t m8xx_wdt_interrupt(int irq, void *dev, struct pt_regs *regs)
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{
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volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
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m8xx_wdt_reset();
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imap->im_sit.sit_piscr |= PISCR_PS; /* clear irq */
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return IRQ_HANDLED;
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}
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void __init m8xx_wdt_handler_install(bd_t * binfo)
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{
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volatile immap_t *imap = (volatile immap_t *)IMAP_ADDR;
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u32 pitc;
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u32 sypcr;
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u32 pitrtclk;
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sypcr = imap->im_siu_conf.sc_sypcr;
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if (!(sypcr & 0x04)) {
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printk(KERN_NOTICE "m8xx_wdt: wdt disabled (SYPCR: 0x%08X)\n",
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sypcr);
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return;
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}
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m8xx_wdt_reset();
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printk(KERN_NOTICE
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"m8xx_wdt: active wdt found (SWTC: 0x%04X, SWP: 0x%01X)\n",
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(sypcr >> 16), sypcr & 0x01);
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wdt_timeout = (sypcr >> 16) & 0xFFFF;
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if (!wdt_timeout)
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wdt_timeout = 0xFFFF;
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if (sypcr & 0x01)
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wdt_timeout *= 2048;
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/*
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* Fire trigger if half of the wdt ticked down
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*/
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if (imap->im_sit.sit_rtcsc & RTCSC_38K)
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pitrtclk = 9600;
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else
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pitrtclk = 8192;
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if ((wdt_timeout) > (UINT_MAX / pitrtclk))
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pitc = wdt_timeout / binfo->bi_intfreq * pitrtclk / 2;
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else
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pitc = pitrtclk * wdt_timeout / binfo->bi_intfreq / 2;
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imap->im_sit.sit_pitc = pitc << 16;
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imap->im_sit.sit_piscr =
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(mk_int_int_mask(PIT_INTERRUPT) << 8) | PISCR_PIE | PISCR_PTE;
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if (request_irq(PIT_INTERRUPT, m8xx_wdt_interrupt, 0, "watchdog", NULL))
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panic("m8xx_wdt: could not allocate watchdog irq!");
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printk(KERN_NOTICE
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"m8xx_wdt: keep-alive trigger installed (PITC: 0x%04X)\n", pitc);
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wdt_timeout /= binfo->bi_intfreq;
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}
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int m8xx_wdt_get_timeout(void)
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{
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return wdt_timeout;
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}
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