hw/riscv: clint: Avoid using hard-coded timebase frequency

At present the CLINT timestamp is using a hard-coded timebase
frequency value SIFIVE_CLINT_TIMEBASE_FREQ. This might not be
true for all boards.

Add a new 'timebase-freq' property to the CLINT device, and
update various functions to accept this as a parameter.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <1598924352-89526-16-git-send-email-bmeng.cn@gmail.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

1 files changed, 15 insertions, 11 deletions

diff --git a/hw/riscv/sifive_clint.c b/hw/riscv/sifive_clint.c
index 15e13d5..fa1ddf2 100644
--- a/hw/riscv/sifive_clint.c
+++ b/hw/riscv/sifive_clint.c
@@ -29,22 +29,23 @@
 #include "hw/riscv/sifive_clint.h"
 #include "qemu/timer.h"
 
-static uint64_t cpu_riscv_read_rtc(void)
+static uint64_t cpu_riscv_read_rtc(uint32_t timebase_freq)
 {
     return muldiv64(qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL),
-        SIFIVE_CLINT_TIMEBASE_FREQ, NANOSECONDS_PER_SECOND);
+        timebase_freq, NANOSECONDS_PER_SECOND);
 }
 
 /*
  * Called when timecmp is written to update the QEMU timer or immediately
  * trigger timer interrupt if mtimecmp <= current timer value.
  */
-static void sifive_clint_write_timecmp(RISCVCPU *cpu, uint64_t value)
+static void sifive_clint_write_timecmp(RISCVCPU *cpu, uint64_t value,
+                                       uint32_t timebase_freq)
 {
     uint64_t next;
     uint64_t diff;
 
-    uint64_t rtc_r = cpu_riscv_read_rtc();
+    uint64_t rtc_r = cpu_riscv_read_rtc(timebase_freq);
 
     cpu->env.timecmp = value;
     if (cpu->env.timecmp <= rtc_r) {
@@ -59,7 +60,7 @@ static void sifive_clint_write_timecmp(RISCVCPU *cpu, uint64_t value)
     diff = cpu->env.timecmp - rtc_r;
     /* back to ns (note args switched in muldiv64) */
     next = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL) +
-        muldiv64(diff, NANOSECONDS_PER_SECOND, SIFIVE_CLINT_TIMEBASE_FREQ);
+        muldiv64(diff, NANOSECONDS_PER_SECOND, timebase_freq);
     timer_mod(cpu->env.timer, next);
 }
 
@@ -112,10 +113,10 @@ static uint64_t sifive_clint_read(void *opaque, hwaddr addr, unsigned size)
         }
     } else if (addr == clint->time_base) {
         /* time_lo */
-        return cpu_riscv_read_rtc() & 0xFFFFFFFF;
+        return cpu_riscv_read_rtc(clint->timebase_freq) & 0xFFFFFFFF;
     } else if (addr == clint->time_base + 4) {
         /* time_hi */
-        return (cpu_riscv_read_rtc() >> 32) & 0xFFFFFFFF;
+        return (cpu_riscv_read_rtc(clint->timebase_freq) >> 32) & 0xFFFFFFFF;
     }
 
     error_report("clint: invalid read: %08x", (uint32_t)addr);
@@ -153,13 +154,13 @@ static void sifive_clint_write(void *opaque, hwaddr addr, uint64_t value,
             /* timecmp_lo */
             uint64_t timecmp_hi = env->timecmp >> 32;
             sifive_clint_write_timecmp(RISCV_CPU(cpu),
-                timecmp_hi << 32 | (value & 0xFFFFFFFF));
+                timecmp_hi << 32 | (value & 0xFFFFFFFF), clint->timebase_freq);
             return;
         } else if ((addr & 0x7) == 4) {
             /* timecmp_hi */
             uint64_t timecmp_lo = env->timecmp;
             sifive_clint_write_timecmp(RISCV_CPU(cpu),
-                value << 32 | (timecmp_lo & 0xFFFFFFFF));
+                value << 32 | (timecmp_lo & 0xFFFFFFFF), clint->timebase_freq);
         } else {
             error_report("clint: invalid timecmp write: %08x", (uint32_t)addr);
         }
@@ -194,6 +195,7 @@ static Property sifive_clint_properties[] = {
     DEFINE_PROP_UINT32("timecmp-base", SiFiveCLINTState, timecmp_base, 0),
     DEFINE_PROP_UINT32("time-base", SiFiveCLINTState, time_base, 0),
     DEFINE_PROP_UINT32("aperture-size", SiFiveCLINTState, aperture_size, 0),
+    DEFINE_PROP_UINT32("timebase-freq", SiFiveCLINTState, timebase_freq, 0),
     DEFINE_PROP_END_OF_LIST(),
 };
 
@@ -232,7 +234,8 @@ type_init(sifive_clint_register_types)
  */
 DeviceState *sifive_clint_create(hwaddr addr, hwaddr size,
     uint32_t hartid_base, uint32_t num_harts, uint32_t sip_base,
-    uint32_t timecmp_base, uint32_t time_base, bool provide_rdtime)
+    uint32_t timecmp_base, uint32_t time_base, uint32_t timebase_freq,
+    bool provide_rdtime)
 {
     int i;
     for (i = 0; i < num_harts; i++) {
@@ -242,7 +245,7 @@ DeviceState *sifive_clint_create(hwaddr addr, hwaddr size,
             continue;
         }
         if (provide_rdtime) {
-            riscv_cpu_set_rdtime_fn(env, cpu_riscv_read_rtc);
+            riscv_cpu_set_rdtime_fn(env, cpu_riscv_read_rtc, timebase_freq);
         }
         env->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL,
                                   &sifive_clint_timer_cb, cpu);
@@ -256,6 +259,7 @@ DeviceState *sifive_clint_create(hwaddr addr, hwaddr size,
     qdev_prop_set_uint32(dev, "timecmp-base", timecmp_base);
     qdev_prop_set_uint32(dev, "time-base", time_base);
     qdev_prop_set_uint32(dev, "aperture-size", size);
+    qdev_prop_set_uint32(dev, "timebase-freq", timebase_freq);
     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
     sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, addr);
     return dev;