[PATCH 02/11] x86, pci: Clean up comment about buggy MMIO config space access for AMD Fam10h CPUs.
Hanjun Guo
hanjun.guo at linaro.org
Tue May 26 05:49:15 PDT 2015
From: Tomasz Nowicki <tomasz.nowicki at linaro.org>
- fix typo
- improve explanation
- add reference to the related document
Signed-off-by: Tomasz Nowicki <tomasz.nowicki at linaro.org>
Signed-off-by: Hanjun Guo <hanjun.guo at linaro.org>
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit at amd.com>
---
arch/x86/include/asm/pci_x86.h | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/arch/x86/include/asm/pci_x86.h b/arch/x86/include/asm/pci_x86.h
index 164e3f8..eddf8f0 100644
--- a/arch/x86/include/asm/pci_x86.h
+++ b/arch/x86/include/asm/pci_x86.h
@@ -154,10 +154,13 @@ extern struct list_head pci_mmcfg_list;
/*
* 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
+ * on their northbridge 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.
+ *
+ * Please refer to the following doc:
+ * "BIOS and Kernel Developer's Guide (BKDG) For AMD Family 10h Processors",
+ * rev. 3.48, sec 2.11.1, "MMIO Configuration Coding Requirements".
*/
static inline unsigned char mmio_config_readb(void __iomem *pos)
{
--
1.9.1
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