kolibrios/drivers/sensors/e_msr.c

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#include <ddk.h>
#define U64_C(x) x ## ULL
#define BIT_64(n) (U64_C(1) << (n))
struct e_msr {
union {
struct {
u32 l;
u32 h;
};
u64 q;
};
};
static void _msr_read(u32 msr, struct e_msr *m)
{
__asm__ __volatile__(
"rdmsr"
:"=a"(m->l), "=d"(m->h)
:"c"(msr)
:"memory"
);
}
static void _msr_write(u32 msr, struct e_msr *m)
{
__asm__ __volatile__(
"wrmsr"
::"a"(m->l), "d"(m->h), "c"(msr)
:"memory"
);
}
static int __flip_bit(u32 msr, u8 bit, bool set)
{
struct e_msr m, m1;
if (bit > 63)
return EINVAL;
_msr_read(msr, &m);
m1 = m;
if (set)
m1.q |= BIT_64(bit);
else
m1.q &= ~BIT_64(bit);
if (m1.q == m.q)
return 0;
_msr_write(msr, &m1);
return 1;
}
int e_msr_set_bit(u32 msr, u8 bit)
{
return __flip_bit(msr, bit, true);
}