diff options
Diffstat (limited to 'arch/powerpc/kernel/rtas-rtc.c')
-rw-r--r-- | arch/powerpc/kernel/rtas-rtc.c | 112 |
1 files changed, 112 insertions, 0 deletions
diff --git a/arch/powerpc/kernel/rtas-rtc.c b/arch/powerpc/kernel/rtas-rtc.c new file mode 100644 index 0000000000..6996214532 --- /dev/null +++ b/arch/powerpc/kernel/rtas-rtc.c @@ -0,0 +1,112 @@ +// SPDX-License-Identifier: GPL-2.0 +#include <linux/kernel.h> +#include <linux/time.h> +#include <linux/timer.h> +#include <linux/init.h> +#include <linux/rtc.h> +#include <linux/delay.h> +#include <linux/ratelimit.h> +#include <asm/rtas.h> +#include <asm/time.h> + + +#define MAX_RTC_WAIT 5000 /* 5 sec */ + +time64_t __init rtas_get_boot_time(void) +{ + int ret[8]; + int error; + unsigned int wait_time; + u64 max_wait_tb; + + max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT; + do { + error = rtas_call(rtas_function_token(RTAS_FN_GET_TIME_OF_DAY), 0, 8, ret); + + wait_time = rtas_busy_delay_time(error); + if (wait_time) { + /* This is boot time so we spin. */ + udelay(wait_time*1000); + } + } while (wait_time && (get_tb() < max_wait_tb)); + + if (error != 0) { + printk_ratelimited(KERN_WARNING + "error: reading the clock failed (%d)\n", + error); + return 0; + } + + return mktime64(ret[0], ret[1], ret[2], ret[3], ret[4], ret[5]); +} + +/* NOTE: get_rtc_time will get an error if executed in interrupt context + * and if a delay is needed to read the clock. In this case we just + * silently return without updating rtc_tm. + */ +void rtas_get_rtc_time(struct rtc_time *rtc_tm) +{ + int ret[8]; + int error; + unsigned int wait_time; + u64 max_wait_tb; + + max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT; + do { + error = rtas_call(rtas_function_token(RTAS_FN_GET_TIME_OF_DAY), 0, 8, ret); + + wait_time = rtas_busy_delay_time(error); + if (wait_time) { + if (in_interrupt()) { + memset(rtc_tm, 0, sizeof(struct rtc_time)); + printk_ratelimited(KERN_WARNING + "error: reading clock " + "would delay interrupt\n"); + return; /* delay not allowed */ + } + msleep(wait_time); + } + } while (wait_time && (get_tb() < max_wait_tb)); + + if (error != 0) { + printk_ratelimited(KERN_WARNING + "error: reading the clock failed (%d)\n", + error); + return; + } + + rtc_tm->tm_sec = ret[5]; + rtc_tm->tm_min = ret[4]; + rtc_tm->tm_hour = ret[3]; + rtc_tm->tm_mday = ret[2]; + rtc_tm->tm_mon = ret[1] - 1; + rtc_tm->tm_year = ret[0] - 1900; +} + +int rtas_set_rtc_time(struct rtc_time *tm) +{ + int error, wait_time; + u64 max_wait_tb; + + max_wait_tb = get_tb() + tb_ticks_per_usec * 1000 * MAX_RTC_WAIT; + do { + error = rtas_call(rtas_function_token(RTAS_FN_SET_TIME_OF_DAY), 7, 1, NULL, + tm->tm_year + 1900, tm->tm_mon + 1, + tm->tm_mday, tm->tm_hour, tm->tm_min, + tm->tm_sec, 0); + + wait_time = rtas_busy_delay_time(error); + if (wait_time) { + if (in_interrupt()) + return 1; /* probably decrementer */ + msleep(wait_time); + } + } while (wait_time && (get_tb() < max_wait_tb)); + + if (error != 0) + printk_ratelimited(KERN_WARNING + "error: setting the clock failed (%d)\n", + error); + + return 0; +} |