Change in ...coreboot[master]: arch/x86: Optimise PCI IO config accessor

[Patrick Georgi (Code Review)]

Patrick Georgi has submitted this change and it was merged. ( https://review.coreboot.org/c/coreboot/+/31754 )

Change subject: arch/x86: Optimise PCI IO config accessor
......................................................................

arch/x86: Optimise PCI IO config accessor

By design only 'reg' parameter can have the two least-
significant bits set. As 'reg' is often a constant,
'0xCFC + (reg & 3)' resolves to an immediate value
already at buildtime, unlike (addr & 3) which depends
of a constant (but non-immediate) value of 'dev' in
ramstage.

Change-Id: I6e729fe800c92b1ce4994ad2b4203072fa75a958
Signed-off-by: Kyösti Mälkki 
Reviewed-on: https://review.coreboot.org/c/coreboot/+/31754
Reviewed-by: Nico Huber 
Tested-by: build bot (Jenkins) 
---
M src/arch/x86/include/arch/pci_io_cfg.h
1 file changed, 4 insertions(+), 4 deletions(-)

Approvals:
  build bot (Jenkins): Verified
  Nico Huber: Looks good to me, approved

diff --git a/src/arch/x86/include/arch/pci_io_cfg.h b/src/arch/x86/include/arch/pci_io_cfg.h
index 317c50a..6c88b3c 100644
--- a/src/arch/x86/include/arch/pci_io_cfg.h
+++ b/src/arch/x86/include/arch/pci_io_cfg.h
@@ -34,7 +34,7 @@
 {
    uint32_t addr = pci_io_encode_addr(dev, reg);
    outl(0x80000000 | (addr & ~3), 0xCF8);
-	return inb(0xCFC + (addr & 3));
+	return inb(0xCFC + (reg & 3));
 }

static __always_inline
@@ -42,7 +42,7 @@
 {
    uint32_t addr = pci_io_encode_addr(dev, reg);
    outl(0x80000000 | (addr & ~3), 0xCF8);
-	return inw(0xCFC + (addr & 2));
+	return inw(0xCFC + (reg & 2));
 }

static __always_inline
@@ -58,7 +58,7 @@
 {
    uint32_t addr = pci_io_encode_addr(dev, reg);
    outl(0x80000000 | (addr & ~3), 0xCF8);
-	outb(value, 0xCFC + (addr & 3));
+	outb(value, 0xCFC + (reg & 3));
 }

static __always_inline
@@ -66,7 +66,7 @@
 {
    uint32_t addr = pci_io_encode_addr(dev, reg);
    outl(0x80000000 | (addr & ~3), 0xCF8);
-	outw(value, 0xCFC + (addr & 2));
+	outw(value, 0xCFC + (reg & 2));
 }

static __always_inline