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 000000000000..1198f2a0e42c --- /dev/null +++ b/arch/x86/include/asm/processor-cyrix.h | |||
@@ -0,0 +1,38 @@ | |||
1 | /* | ||
2 | * NSC/Cyrix CPU indexed register access. Must be inlined instead of | ||
3 | * macros to ensure correct access ordering | ||
4 | * Access order is always 0x22 (=offset), 0x23 (=value) | ||
5 | * | ||
6 | * When using the old macros a line like | ||
7 | * setCx86(CX86_CCR2, getCx86(CX86_CCR2) | 0x88); | ||
8 | * gets expanded to: | ||
9 | * do { | ||
10 | * outb((CX86_CCR2), 0x22); | ||
11 | * outb((({ | ||
12 | * outb((CX86_CCR2), 0x22); | ||
13 | * inb(0x23); | ||
14 | * }) | 0x88), 0x23); | ||
15 | * } while (0); | ||
16 | * | ||
17 | * which in fact violates the access order (= 0x22, 0x22, 0x23, 0x23). | ||
18 | */ | ||
19 | |||
20 | static inline u8 getCx86(u8 reg) | ||
21 | { | ||
22 | outb(reg, 0x22); | ||
23 | return inb(0x23); | ||
24 | } | ||
25 | |||
26 | static inline void setCx86(u8 reg, u8 data) | ||
27 | { | ||
28 | outb(reg, 0x22); | ||
29 | outb(data, 0x23); | ||
30 | } | ||
31 | |||
32 | #define getCx86_old(reg) ({ outb((reg), 0x22); inb(0x23); }) | ||
33 | |||
34 | #define setCx86_old(reg, data) do { \ | ||
35 | outb((reg), 0x22); \ | ||
36 | outb((data), 0x23); \ | ||
37 | } while (0) | ||
38 | |||