From 3320ad994afb2c44ad34b3b34c3c5cf0da297331 Mon Sep 17 00:00:00 2001 From: dean gaudet Date: Fri, 10 Aug 2007 22:30:59 +0200 Subject: x86: Work around mmio config space quirk on AMD Fam10h Some broken devices have been discovered to require %al/%ax/%eax registers for MMIO config space accesses. Modify mmconfig.c to use these registers explicitly (rather than modify the global readb/writeb/etc inlines). AK: also changed i386 to always use eax AK: moved change to extended space probing to different patch AK: reworked with inlines according to Linus' requirements. AK: improve comments. Signed-off-by: dean gaudet Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/i386/pci/pci.h | 43 +++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 43 insertions(+) (limited to 'arch/i386/pci/pci.h') diff --git a/arch/i386/pci/pci.h b/arch/i386/pci/pci.h index e58bae2076a..8c66f275756 100644 --- a/arch/i386/pci/pci.h +++ b/arch/i386/pci/pci.h @@ -104,3 +104,46 @@ extern DECLARE_BITMAP(pci_mmcfg_fallback_slots, 32*PCI_MMCFG_MAX_CHECK_BUS); extern int __init pci_mmcfg_arch_reachable(unsigned int seg, unsigned int bus, unsigned int devfn); extern int __init pci_mmcfg_arch_init(void); + +/* + * AMD Fam10h CPUs are buggy, and cannot access MMIO config space + * on their northbrige except through the * %eax register. As such, you MUST + * NOT use normal IOMEM accesses, you need to only use the magic mmio-config + * accessor functions. + * In fact just use pci_config_*, nothing else please. + */ +static inline unsigned char mmio_config_readb(void __iomem *pos) +{ + u8 val; + asm volatile("movb (%1),%%al" : "=a" (val) : "r" (pos)); + return val; +} + +static inline unsigned short mmio_config_readw(void __iomem *pos) +{ + u16 val; + asm volatile("movw (%1),%%ax" : "=a" (val) : "r" (pos)); + return val; +} + +static inline unsigned int mmio_config_readl(void __iomem *pos) +{ + u32 val; + asm volatile("movl (%1),%%eax" : "=a" (val) : "r" (pos)); + return val; +} + +static inline void mmio_config_writeb(void __iomem *pos, u8 val) +{ + asm volatile("movb %%al,(%1)" :: "a" (val), "r" (pos) : "memory"); +} + +static inline void mmio_config_writew(void __iomem *pos, u16 val) +{ + asm volatile("movw %%ax,(%1)" :: "a" (val), "r" (pos) : "memory"); +} + +static inline void mmio_config_writel(void __iomem *pos, u32 val) +{ + asm volatile("movl %%eax,(%1)" :: "a" (val), "r" (pos) : "memory"); +} -- cgit v1.2.3