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Diffstat (limited to 'arch/powerpc/platforms/powermac/time.c')
| -rw-r--r-- | arch/powerpc/platforms/powermac/time.c | 243 |
1 files changed, 243 insertions, 0 deletions
diff --git a/arch/powerpc/platforms/powermac/time.c b/arch/powerpc/platforms/powermac/time.c new file mode 100644 index 000000000..8633891b7 --- /dev/null +++ b/arch/powerpc/platforms/powermac/time.c @@ -0,0 +1,243 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Support for periodic interrupts (100 per second) and for getting + * the current time from the RTC on Power Macintoshes. + * + * We use the decrementer register for our periodic interrupts. + * + * Paul Mackerras August 1996. + * Copyright (C) 1996 Paul Mackerras. + * Copyright (C) 2003-2005 Benjamin Herrenschmidt. + * + */ +#include <linux/errno.h> +#include <linux/sched.h> +#include <linux/kernel.h> +#include <linux/param.h> +#include <linux/string.h> +#include <linux/mm.h> +#include <linux/init.h> +#include <linux/time.h> +#include <linux/adb.h> +#include <linux/cuda.h> +#include <linux/pmu.h> +#include <linux/interrupt.h> +#include <linux/hardirq.h> +#include <linux/rtc.h> +#include <linux/of_address.h> + +#include <asm/early_ioremap.h> +#include <asm/sections.h> +#include <asm/machdep.h> +#include <asm/time.h> +#include <asm/nvram.h> +#include <asm/smu.h> + +#include "pmac.h" + +#undef DEBUG + +#ifdef DEBUG +#define DBG(x...) printk(x) +#else +#define DBG(x...) +#endif + +/* + * Calibrate the decrementer frequency with the VIA timer 1. + */ +#define VIA_TIMER_FREQ_6 4700000 /* time 1 frequency * 6 */ + +/* VIA registers */ +#define RS 0x200 /* skip between registers */ +#define T1CL (4*RS) /* Timer 1 ctr/latch (low 8 bits) */ +#define T1CH (5*RS) /* Timer 1 counter (high 8 bits) */ +#define T1LL (6*RS) /* Timer 1 latch (low 8 bits) */ +#define T1LH (7*RS) /* Timer 1 latch (high 8 bits) */ +#define ACR (11*RS) /* Auxiliary control register */ +#define IFR (13*RS) /* Interrupt flag register */ + +/* Bits in ACR */ +#define T1MODE 0xc0 /* Timer 1 mode */ +#define T1MODE_CONT 0x40 /* continuous interrupts */ + +/* Bits in IFR and IER */ +#define T1_INT 0x40 /* Timer 1 interrupt */ + +long __init pmac_time_init(void) +{ + s32 delta = 0; +#if defined(CONFIG_NVRAM) && defined(CONFIG_PPC32) + int dst; + + delta = ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x9)) << 16; + delta |= ((s32)pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xa)) << 8; + delta |= pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0xb); + if (delta & 0x00800000UL) + delta |= 0xFF000000UL; + dst = ((pmac_xpram_read(PMAC_XPRAM_MACHINE_LOC + 0x8) & 0x80) != 0); + printk("GMT Delta read from XPRAM: %d minutes, DST: %s\n", delta/60, + dst ? "on" : "off"); +#endif + return delta; +} + +#ifdef CONFIG_PMAC_SMU +static time64_t smu_get_time(void) +{ + struct rtc_time tm; + + if (smu_get_rtc_time(&tm, 1)) + return 0; + return rtc_tm_to_time64(&tm); +} +#endif + +/* Can't be __init, it's called when suspending and resuming */ +time64_t pmac_get_boot_time(void) +{ + /* Get the time from the RTC, used only at boot time */ + switch (sys_ctrler) { +#ifdef CONFIG_ADB_CUDA + case SYS_CTRLER_CUDA: + return cuda_get_time(); +#endif +#ifdef CONFIG_ADB_PMU + case SYS_CTRLER_PMU: + return pmu_get_time(); +#endif +#ifdef CONFIG_PMAC_SMU + case SYS_CTRLER_SMU: + return smu_get_time(); +#endif + default: + return 0; + } +} + +void pmac_get_rtc_time(struct rtc_time *tm) +{ + /* Get the time from the RTC, used only at boot time */ + switch (sys_ctrler) { +#ifdef CONFIG_ADB_CUDA + case SYS_CTRLER_CUDA: + rtc_time64_to_tm(cuda_get_time(), tm); + break; +#endif +#ifdef CONFIG_ADB_PMU + case SYS_CTRLER_PMU: + rtc_time64_to_tm(pmu_get_time(), tm); + break; +#endif +#ifdef CONFIG_PMAC_SMU + case SYS_CTRLER_SMU: + smu_get_rtc_time(tm, 1); + break; +#endif + default: + ; + } +} + +int pmac_set_rtc_time(struct rtc_time *tm) +{ + switch (sys_ctrler) { +#ifdef CONFIG_ADB_CUDA + case SYS_CTRLER_CUDA: + return cuda_set_rtc_time(tm); +#endif +#ifdef CONFIG_ADB_PMU + case SYS_CTRLER_PMU: + return pmu_set_rtc_time(tm); +#endif +#ifdef CONFIG_PMAC_SMU + case SYS_CTRLER_SMU: + return smu_set_rtc_time(tm, 1); +#endif + default: + return -ENODEV; + } +} + +#ifdef CONFIG_PPC32 +/* + * Calibrate the decrementer register using VIA timer 1. + * This is used both on powermacs and CHRP machines. + */ +static int __init via_calibrate_decr(void) +{ + struct device_node *vias; + volatile unsigned char __iomem *via; + int count = VIA_TIMER_FREQ_6 / 100; + unsigned int dstart, dend; + struct resource rsrc; + + vias = of_find_node_by_name(NULL, "via-cuda"); + if (vias == NULL) + vias = of_find_node_by_name(NULL, "via-pmu"); + if (vias == NULL) + vias = of_find_node_by_name(NULL, "via"); + if (vias == NULL || of_address_to_resource(vias, 0, &rsrc)) { + of_node_put(vias); + return 0; + } + of_node_put(vias); + via = early_ioremap(rsrc.start, resource_size(&rsrc)); + if (via == NULL) { + printk(KERN_ERR "Failed to map VIA for timer calibration !\n"); + return 0; + } + + /* set timer 1 for continuous interrupts */ + out_8(&via[ACR], (via[ACR] & ~T1MODE) | T1MODE_CONT); + /* set the counter to a small value */ + out_8(&via[T1CH], 2); + /* set the latch to `count' */ + out_8(&via[T1LL], count); + out_8(&via[T1LH], count >> 8); + /* wait until it hits 0 */ + while ((in_8(&via[IFR]) & T1_INT) == 0) + ; + dstart = get_dec(); + /* clear the interrupt & wait until it hits 0 again */ + in_8(&via[T1CL]); + while ((in_8(&via[IFR]) & T1_INT) == 0) + ; + dend = get_dec(); + + ppc_tb_freq = (dstart - dend) * 100 / 6; + + early_iounmap((void *)via, resource_size(&rsrc)); + + return 1; +} +#endif + +/* + * Query the OF and get the decr frequency. + */ +void __init pmac_calibrate_decr(void) +{ + generic_calibrate_decr(); + +#ifdef CONFIG_PPC32 + /* We assume MacRISC2 machines have correct device-tree + * calibration. That's better since the VIA itself seems + * to be slightly off. --BenH + */ + if (!of_machine_is_compatible("MacRISC2") && + !of_machine_is_compatible("MacRISC3") && + !of_machine_is_compatible("MacRISC4")) + if (via_calibrate_decr()) + return; + + /* Special case: QuickSilver G4s seem to have a badly calibrated + * timebase-frequency in OF, VIA is much better on these. We should + * probably implement calibration based on the KL timer on these + * machines anyway... -BenH + */ + if (of_machine_is_compatible("PowerMac3,5")) + if (via_calibrate_decr()) + return; +#endif +} |