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>

hw/riscv/microchip_pfsoc.c

@@ -60,6 +60,9 @@
 #define BIOS_FILENAME   "hss.bin"
 #define RESET_VECTOR    0x20220000
 
+/* CLINT timebase frequency */
+#define CLINT_TIMEBASE_FREQ 1000000
+
 /* GEM version */
 #define GEM_REVISION    0x0107010c
 
@@ -187,7 +190,8 @@ static void microchip_pfsoc_soc_realize(DeviceState *dev, Error **errp)
     /* CLINT */
     sifive_clint_create(memmap[MICROCHIP_PFSOC_CLINT].base,
         memmap[MICROCHIP_PFSOC_CLINT].size, 0, ms->smp.cpus,
-        SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE, false);
+        SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE,
+        CLINT_TIMEBASE_FREQ, false);
 
     /* L2 cache controller */
     create_unimplemented_device("microchip.pfsoc.l2cc",

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;

hw/riscv/sifive_e.c

@@ -213,7 +213,8 @@ static void sifive_e_soc_realize(DeviceState *dev, Error **errp)
         memmap[SIFIVE_E_PLIC].size);
     sifive_clint_create(memmap[SIFIVE_E_CLINT].base,
         memmap[SIFIVE_E_CLINT].size, 0, ms->smp.cpus,
-        SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE, false);
+        SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE,
+        SIFIVE_CLINT_TIMEBASE_FREQ, false);
     create_unimplemented_device("riscv.sifive.e.aon",
         memmap[SIFIVE_E_AON].base, memmap[SIFIVE_E_AON].size);
     sifive_e_prci_create(memmap[SIFIVE_E_PRCI].base);

hw/riscv/sifive_u.c

@@ -706,7 +706,8 @@ static void sifive_u_soc_realize(DeviceState *dev, Error **errp)
         serial_hd(1), qdev_get_gpio_in(DEVICE(s->plic), SIFIVE_U_UART1_IRQ));
     sifive_clint_create(memmap[SIFIVE_U_CLINT].base,
         memmap[SIFIVE_U_CLINT].size, 0, ms->smp.cpus,
-        SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE, false);
+        SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE,
+        SIFIVE_CLINT_TIMEBASE_FREQ, false);
 
     if (!sysbus_realize(SYS_BUS_DEVICE(&s->prci), errp)) {
         return;

hw/riscv/spike.c

@@ -242,7 +242,8 @@ static void spike_board_init(MachineState *machine)
         sifive_clint_create(
             memmap[SPIKE_CLINT].base + i * memmap[SPIKE_CLINT].size,
             memmap[SPIKE_CLINT].size, base_hartid, hart_count,
-            SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE, false);
+            SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE,
+            SIFIVE_CLINT_TIMEBASE_FREQ, false);
     }
 
     /* register system main memory (actual RAM) */

hw/riscv/virt.c

@@ -541,7 +541,8 @@ static void virt_machine_init(MachineState *machine)
         sifive_clint_create(
             memmap[VIRT_CLINT].base + i * memmap[VIRT_CLINT].size,
             memmap[VIRT_CLINT].size, base_hartid, hart_count,
-            SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE, true);
+            SIFIVE_SIP_BASE, SIFIVE_TIMECMP_BASE, SIFIVE_TIME_BASE,
+            SIFIVE_CLINT_TIMEBASE_FREQ, true);
 
         /* Per-socket PLIC hart topology configuration string */
         plic_hart_config_len =

include/hw/riscv/sifive_clint.h

@@ -39,11 +39,13 @@ typedef struct SiFiveCLINTState {
     uint32_t timecmp_base;
     uint32_t time_base;
     uint32_t aperture_size;
+    uint32_t timebase_freq;
 } SiFiveCLINTState;
 
 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);
 
 enum {
     SIFIVE_SIP_BASE     = 0x0,

target/riscv/cpu.h

@@ -219,7 +219,8 @@ struct CPURISCVState {
     pmp_table_t pmp_state;
 
     /* machine specific rdtime callback */
-    uint64_t (*rdtime_fn)(void);
+    uint64_t (*rdtime_fn)(uint32_t);
+    uint32_t rdtime_fn_arg;
 
     /* True if in debugger mode.  */
     bool debugger;
@@ -350,7 +351,8 @@ void riscv_cpu_swap_hypervisor_regs(CPURISCVState *env);
 int riscv_cpu_claim_interrupts(RISCVCPU *cpu, uint32_t interrupts);
 uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value);
 #define BOOL_TO_MASK(x) (-!!(x)) /* helper for riscv_cpu_update_mip value */
-void riscv_cpu_set_rdtime_fn(CPURISCVState *env, uint64_t (*fn)(void));
+void riscv_cpu_set_rdtime_fn(CPURISCVState *env, uint64_t (*fn)(uint32_t),
+                             uint32_t arg);
 #endif
 void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv);
 

target/riscv/cpu_helper.c

@@ -276,9 +276,11 @@ uint32_t riscv_cpu_update_mip(RISCVCPU *cpu, uint32_t mask, uint32_t value)
     return old;
 }
 
-void riscv_cpu_set_rdtime_fn(CPURISCVState *env, uint64_t (*fn)(void))
+void riscv_cpu_set_rdtime_fn(CPURISCVState *env, uint64_t (*fn)(uint32_t),
+                             uint32_t arg)
 {
     env->rdtime_fn = fn;
+    env->rdtime_fn_arg = arg;
 }
 
 void riscv_cpu_set_mode(CPURISCVState *env, target_ulong newpriv)

target/riscv/csr.c

@@ -351,7 +351,7 @@ static int read_time(CPURISCVState *env, int csrno, target_ulong *val)
         return -RISCV_EXCP_ILLEGAL_INST;
     }
 
-    *val = env->rdtime_fn() + delta;
+    *val = env->rdtime_fn(env->rdtime_fn_arg) + delta;
     return 0;
 }
 
@@ -364,7 +364,7 @@ static int read_timeh(CPURISCVState *env, int csrno, target_ulong *val)
         return -RISCV_EXCP_ILLEGAL_INST;
     }
 
-    *val = (env->rdtime_fn() + delta) >> 32;
+    *val = (env->rdtime_fn(env->rdtime_fn_arg) + delta) >> 32;
     return 0;
 }
 #endif