ARM PL031 RTC emulation.

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3037 c046a42c-6fe2-441c-8c8c-71466251a162

1 files changed, 219 insertions, 0 deletions

diff --git a/hw/pl031.c b/hw/pl031.c
new file mode 100644
index 000000000..7e8098ba5
--- /dev/null
+++ b/hw/pl031.c
@@ -0,0 +1,219 @@
+/*
+ * ARM AMBA PrimeCell PL031 RTC
+ *
+ * Copyright (c) 2007 CodeSourcery
+ *
+ * This file is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ */
+
+#include"vl.h"
+
+//#define DEBUG_PL031
+
+#ifdef DEBUG_PL031
+#define DPRINTF(fmt, args...) \
+do { printf("pl031: " fmt , ##args); } while (0)
+#else
+#define DPRINTF(fmt, args...) do {} while(0)
+#endif
+
+#define RTC_DR      0x00    /* Data read register */
+#define RTC_MR      0x04    /* Match register */
+#define RTC_LR      0x08    /* Data load register */
+#define RTC_CR      0x0c    /* Control register */
+#define RTC_IMSC    0x10    /* Interrupt mask and set register */
+#define RTC_RIS     0x14    /* Raw interrupt status register */
+#define RTC_MIS     0x18    /* Masked interrupt status register */
+#define RTC_ICR     0x1c    /* Interrupt clear register */
+
+typedef struct {
+    QEMUTimer *timer;
+    qemu_irq irq;
+    uint32_t base;
+
+    uint64_t start_time;
+    uint32_t tick_offset;
+
+    uint32_t mr;
+    uint32_t lr;
+    uint32_t cr;
+    uint32_t im;
+    uint32_t is;
+} pl031_state;
+
+static const unsigned char pl031_id[] = {
+    0x31, 0x10, 0x14, 0x00,         /* Device ID        */
+    0x0d, 0xf0, 0x05, 0xb1          /* Cell ID      */
+};
+
+static void pl031_update(pl031_state *s)
+{
+    qemu_set_irq(s->irq, s->is & s->im);
+}
+
+static void pl031_interrupt(void * opaque)
+{
+    pl031_state *s = (pl031_state *)opaque;
+
+    s->im = 1;
+    DPRINTF("Alarm raised\n");
+    pl031_update(s);
+}
+
+static uint32_t pl031_get_count(pl031_state *s)
+{
+    /* This assumes qemu_get_clock returns the time since the machine was
+       created.  */
+    return s->tick_offset + qemu_get_clock(vm_clock) / ticks_per_sec;
+}
+
+static void pl031_set_alarm(pl031_state *s)
+{
+    int64_t now;
+    uint32_t ticks;
+
+    now = qemu_get_clock(vm_clock);
+    ticks = s->tick_offset + now / ticks_per_sec;
+
+    /* The timer wraps around.  This subtraction also wraps in the same way,
+       and gives correct results when alarm < now_ticks.  */
+    ticks = s->mr - ticks;
+    DPRINTF("Alarm set in %ud ticks\n", ticks);
+    if (ticks == 0) {
+        qemu_del_timer(s->timer);
+        pl031_interrupt(s);
+    } else {
+        qemu_mod_timer(s->timer, now + (int64_t)ticks * ticks_per_sec);
+    }
+}
+
+static uint32_t pl031_read(void *opaque, target_phys_addr_t offset)
+{
+    pl031_state *s = (pl031_state *)opaque;
+
+    offset -= s->base;
+
+    if (offset >= 0xfe0  &&  offset < 0x1000)
+        return pl031_id[(offset - 0xfe0) >> 2];
+
+    switch (offset) {
+    case RTC_DR:
+        return pl031_get_count(s);
+    case RTC_MR:
+        return s->mr;
+    case RTC_IMSC:
+        return s->im;
+    case RTC_RIS:
+        return s->is;
+    case RTC_LR:
+        return s->lr;
+    case RTC_CR:
+        /* RTC is permanently enabled.  */
+        return 1;
+    case RTC_MIS:
+        return s->is & s->im;
+    case RTC_ICR:
+        fprintf(stderr, "qemu: pl031_read: Unexpected offset 0x%x\n",
+                (int)offset);
+        break;
+    default:
+        cpu_abort(cpu_single_env, "pl031_read: Bad offset 0x%x\n",
+                  (int)offset);
+        break;
+    }
+
+    return 0;
+}
+
+static void pl031_write(void * opaque, target_phys_addr_t offset,
+                        uint32_t value)
+{
+    pl031_state *s = (pl031_state *)opaque;
+
+    offset -= s->base;
+
+    switch (offset) {
+    case RTC_LR:
+        s->tick_offset += value - pl031_get_count(s);
+        pl031_set_alarm(s);
+        break;
+    case RTC_MR:
+        s->mr = value;
+        pl031_set_alarm(s);
+        break;
+    case RTC_IMSC:
+        s->im = value & 1;
+        DPRINTF("Interrupt mask %d\n", s->im);
+        pl031_update(s);
+        break;
+    case RTC_ICR:
+        /* The PL031 documentation (DDI0224B) states that the interupt is
+           cleared when bit 0 of the written value is set.  However the
+           arm926e documentation (DDI0287B) states that the interrupt is
+           cleared when any value is written.  */
+        DPRINTF("Interrupt cleared");
+        s->is = 0;
+        pl031_update(s);
+        break;
+    case RTC_CR:
+        /* Written value is ignored.  */
+        break;
+
+    case RTC_DR:
+    case RTC_MIS:
+    case RTC_RIS:
+        fprintf(stderr, "qemu: pl031_write: Unexpected offset 0x%x\n",
+                (int)offset);
+        break;
+
+    default:
+        cpu_abort(cpu_single_env, "pl031_write: Bad offset 0x%x\n",
+                  (int)offset);
+        break;
+    }
+}
+
+static CPUWriteMemoryFunc * pl031_writefn[] = {
+    pl031_write,
+    pl031_write,
+    pl031_write
+};
+
+static CPUReadMemoryFunc * pl031_readfn[] = {
+    pl031_read,
+    pl031_read,
+    pl031_read
+};
+
+void pl031_init(uint32_t base, qemu_irq irq)
+{
+    int iomemtype;
+    pl031_state *s;
+    time_t ti;
+    struct tm *tm;
+
+    s = qemu_mallocz(sizeof(pl031_state));
+    if (!s)
+        cpu_abort(cpu_single_env, "pl031_init: Out of memory\n");
+
+    iomemtype = cpu_register_io_memory(0, pl031_readfn, pl031_writefn, s);
+    if (iomemtype == -1)
+        cpu_abort(cpu_single_env, "pl031_init: Can't register I/O memory\n");
+
+    cpu_register_physical_memory(base, 0x00001000, iomemtype);
+
+    s->base = base;
+    s->irq  = irq;
+    /* ??? We assume vm_clock is zero at this point.  */
+    time(&ti);
+    if (rtc_utc)
+        tm = gmtime(&ti);
+    else
+        tm = localtime(&ti);
+    s->tick_offset = mktime(tm);
+
+    s->timer = qemu_new_timer(vm_clock, pl031_interrupt, s);
+}