diff options
Diffstat (limited to 'arch/x86/include/asm/processor-cyrix.h')
-rw-r--r-- | arch/x86/include/asm/processor-cyrix.h | 38 |
1 files changed, 38 insertions, 0 deletions
diff --git a/arch/x86/include/asm/processor-cyrix.h b/arch/x86/include/asm/processor-cyrix.h new file mode 100644 index 0000000..1198f2a --- /dev/null +++ b/arch/x86/include/asm/processor-cyrix.h @@ -0,0 +1,38 @@ +/* + * NSC/Cyrix CPU indexed register access. Must be inlined instead of + * macros to ensure correct access ordering + * Access order is always 0x22 (=offset), 0x23 (=value) + * + * When using the old macros a line like + * setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x88); + * gets expanded to: + * do { + * outb((CX86_CCR2), 0x22); + * outb((({ + * outb((CX86_CCR2), 0x22); + * inb(0x23); + * }) | 0x88), 0x23); + * } while (0); + * + * which in fact violates the access order (= 0x22, 0x22, 0x23, 0x23). + */ + +static inline u8 getCx86(u8 reg) +{ + outb(reg, 0x22); + return inb(0x23); +} + +static inline void setCx86(u8 reg, u8 data) +{ + outb(reg, 0x22); + outb(data, 0x23); +} + +#define getCx86_old(reg) ({ outb((reg), 0x22); inb(0x23); }) + +#define setCx86_old(reg, data) do { \ + outb((reg), 0x22); \ + outb((data), 0x23); \ +} while (0) + |