diff options
| author | Philippe Mathieu-Daudé <f4bug@amsat.org> | 2020-10-12 11:57:51 +0200 |
|---|---|---|
| committer | Philippe Mathieu-Daudé <f4bug@amsat.org> | 2020-10-17 11:13:15 +0200 |
| commit | d225b5122029c3d6293aab6e2d0a05597fc92ba4 (patch) | |
| tree | c2f16e1f4469854dd70cace1ade25b293a825e04 /target/mips/cpu.c | |
| parent | 8dadffc01700f79fd66db972fff3a93a594715ee (diff) | |
target/mips: Move cp0_count_ns to CPUMIPSState
Currently the CP0 timer period is fixed at 10 ns, corresponding
to a fixed CPU frequency of 200 MHz (using half the speed of the
CPU).
In few commits we will be able to use a different CPU frequency.
In preparation, move the cp0_count_ns variable to CPUMIPSState
so we can modify it.
Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Jiaxun Yang <jiaxun.yang@flygoat.com>
Message-Id: <20201012095804.3335117-9-f4bug@amsat.org>
Diffstat (limited to 'target/mips/cpu.c')
| -rw-r--r-- | target/mips/cpu.c | 21 |
1 files changed, 21 insertions, 0 deletions
diff --git a/target/mips/cpu.c b/target/mips/cpu.c index e86cd06548..84b727fefa 100644 --- a/target/mips/cpu.c +++ b/target/mips/cpu.c @@ -134,6 +134,25 @@ static void mips_cpu_disas_set_info(CPUState *s, disassemble_info *info) } } +/* + * Since commit 6af0bf9c7c3 this model assumes a CPU clocked at 200MHz + * and a CP0 timer running at half the clock of the CPU (cp0_count_rate = 2). + * + * TIMER_FREQ_HZ = CPU_FREQ_HZ / CP0_COUNT_RATE = 200 MHz / 2 = 100 MHz + * + * TIMER_PERIOD_NS = 1 / TIMER_FREQ_HZ = 10 ns + */ +#define CPU_FREQ_HZ_DEFAULT 200000000 +#define CP0_COUNT_RATE_DEFAULT 2 +#define TIMER_PERIOD_DEFAULT 10 /* 1 / (CPU_FREQ_HZ / CP0_COUNT_RATE) */ + +static void mips_cp0_period_set(MIPSCPU *cpu) +{ + CPUMIPSState *env = &cpu->env; + + env->cp0_count_ns = TIMER_PERIOD_DEFAULT; +} + static void mips_cpu_realizefn(DeviceState *dev, Error **errp) { CPUState *cs = CPU(dev); @@ -141,6 +160,8 @@ static void mips_cpu_realizefn(DeviceState *dev, Error **errp) MIPSCPUClass *mcc = MIPS_CPU_GET_CLASS(dev); Error *local_err = NULL; + mips_cp0_period_set(cpu); + cpu_exec_realizefn(cs, &local_err); if (local_err != NULL) { error_propagate(errp, local_err); |