Commit 3320ad99 authored by dean gaudet's avatar dean gaudet Committed by Linus Torvalds
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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: default avatardean gaudet <dean@arctic.org>
Signed-off-by: default avatarAndi Kleen <ak@suse.de>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 9535239f
......@@ -82,16 +82,15 @@ static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
switch (len) {
case 1:
*value = readb(mmcfg_virt_addr + reg);
*value = mmio_config_readb(mmcfg_virt_addr + reg);
break;
case 2:
*value = readw(mmcfg_virt_addr + reg);
*value = mmio_config_readw(mmcfg_virt_addr + reg);
break;
case 4:
*value = readl(mmcfg_virt_addr + reg);
*value = mmio_config_readl(mmcfg_virt_addr + reg);
break;
}
spin_unlock_irqrestore(&pci_config_lock, flags);
return 0;
......@@ -116,16 +115,15 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
switch (len) {
case 1:
writeb(value, mmcfg_virt_addr + reg);
mmio_config_writeb(mmcfg_virt_addr, value);
break;
case 2:
writew(value, mmcfg_virt_addr + reg);
mmio_config_writew(mmcfg_virt_addr, value);
break;
case 4:
writel(value, mmcfg_virt_addr + reg);
mmio_config_writel(mmcfg_virt_addr, value);
break;
}
spin_unlock_irqrestore(&pci_config_lock, flags);
return 0;
......
......@@ -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");
}
......@@ -66,13 +66,13 @@ static int pci_mmcfg_read(unsigned int seg, unsigned int bus,
switch (len) {
case 1:
*value = readb(addr + reg);
*value = mmio_config_readb(addr + reg);
break;
case 2:
*value = readw(addr + reg);
*value = mmio_config_readw(addr + reg);
break;
case 4:
*value = readl(addr + reg);
*value = mmio_config_readl(addr + reg);
break;
}
......@@ -94,13 +94,13 @@ static int pci_mmcfg_write(unsigned int seg, unsigned int bus,
switch (len) {
case 1:
writeb(value, addr + reg);
mmio_config_writeb(addr + reg, value);
break;
case 2:
writew(value, addr + reg);
mmio_config_writew(addr + reg, value);
break;
case 4:
writel(value, addr + reg);
mmio_config_writel(addr + reg, value);
break;
}
......
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