507279db18
This patch attempts to handle RTAS "busy" return codes in a more simple and consistent manner. Typical callers of RTAS shouldn't have to manage wait times and delay calls. This patch also changes the kernel to use msleep() rather than udelay() when a runtime delay is necessary. This will avoid CPU soft lockups for extended delay conditions. Signed-off-by: John Rose <johnrose@austin.ibm.com> Signed-off-by: Paul Mackerras <paulus@samba.org>
108 lines
2.7 KiB
C
108 lines
2.7 KiB
C
#include <linux/kernel.h>
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#include <linux/time.h>
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#include <linux/timer.h>
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#include <linux/init.h>
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#include <linux/rtc.h>
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#include <linux/delay.h>
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#include <asm/prom.h>
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#include <asm/rtas.h>
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#include <asm/time.h>
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#define MAX_RTC_WAIT 5000 /* 5 sec */
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#define RTAS_CLOCK_BUSY (-2)
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unsigned long __init rtas_get_boot_time(void)
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{
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int ret[8];
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int error;
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unsigned int wait_time;
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u64 max_wait_tb;
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max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
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do {
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error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
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wait_time = rtas_busy_delay_time(error);
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if (wait_time) {
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/* This is boot time so we spin. */
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udelay(wait_time*1000);
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}
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} while (wait_time && (get_tb() < max_wait_tb));
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if (error != 0 && printk_ratelimit()) {
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printk(KERN_WARNING "error: reading the clock failed (%d)\n",
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error);
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return 0;
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}
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return mktime(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]);
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}
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/* NOTE: get_rtc_time will get an error if executed in interrupt context
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* and if a delay is needed to read the clock. In this case we just
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* silently return without updating rtc_tm.
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*/
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void rtas_get_rtc_time(struct rtc_time *rtc_tm)
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{
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int ret[8];
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int error;
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unsigned int wait_time;
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u64 max_wait_tb;
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max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
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do {
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error = rtas_call(rtas_token("get-time-of-day"), 0, 8, ret);
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wait_time = rtas_busy_delay_time(error);
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if (wait_time) {
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if (in_interrupt() && printk_ratelimit()) {
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memset(rtc_tm, 0, sizeof(struct rtc_time));
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printk(KERN_WARNING "error: reading clock"
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" would delay interrupt\n");
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return; /* delay not allowed */
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}
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msleep(wait_time);
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}
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} while (wait_time && (get_tb() < max_wait_tb));
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if (error != 0 && printk_ratelimit()) {
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printk(KERN_WARNING "error: reading the clock failed (%d)\n",
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error);
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return;
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}
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rtc_tm->tm_sec = ret[5];
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rtc_tm->tm_min = ret[4];
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rtc_tm->tm_hour = ret[3];
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rtc_tm->tm_mday = ret[2];
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rtc_tm->tm_mon = ret[1] - 1;
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rtc_tm->tm_year = ret[0] - 1900;
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}
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int rtas_set_rtc_time(struct rtc_time *tm)
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{
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int error, wait_time;
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u64 max_wait_tb;
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max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT;
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do {
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error = rtas_call(rtas_token("set-time-of-day"), 7, 1, NULL,
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tm->tm_year + 1900, tm->tm_mon + 1,
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tm->tm_mday, tm->tm_hour, tm->tm_min,
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tm->tm_sec, 0);
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wait_time = rtas_busy_delay_time(error);
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if (wait_time) {
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if (in_interrupt())
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return 1; /* probably decrementer */
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msleep(wait_time);
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}
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} while (wait_time && (get_tb() < max_wait_tb));
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if (error != 0 && printk_ratelimit())
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printk(KERN_WARNING "error: setting the clock failed (%d)\n",
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error);
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return 0;
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}
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