summaryrefslogtreecommitdiffstats
path: root/arch/powerpc/platforms/powermac/time.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/powerpc/platforms/powermac/time.c')
-rw-r--r--arch/powerpc/platforms/powermac/time.c243
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..31d6213a6
--- /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 <asm/sections.h>
+#include <asm/prom.h>
+#include <asm/io.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 = 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;
+
+ iounmap(via);
+
+ 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
+}