pciexp: Refactor extended capability handling
Add some inline functions for the bit-wise operations, change the loop
body to an if-bail-out style and remove stateful variables.
Change-Id: Ia8db915f375737064e3486d313383d9b6c3eb2b8
Signed-off-by: Nico Huber <nico.h@gmx.de>
Reviewed-on: https://review.coreboot.org/c/coreboot/+/66458
Reviewed-by: Bill XIE <persmule@hardenedlinux.org>
Reviewed-by: Tim Wawrzynczak <twawrzynczak@chromium.org>
Tested-by: build bot (Jenkins) <no-reply@coreboot.org>
diff --git a/src/device/pciexp_device.c b/src/device/pciexp_device.c
index 903ecdd..05ac4fc 100644
--- a/src/device/pciexp_device.c
+++ b/src/device/pciexp_device.c
@@ -9,22 +9,32 @@
#include <device/pci_ops.h>
#include <device/pciexp.h>
-static unsigned int pciexp_get_ext_cap_offset(const struct device *dev, unsigned int cap,
- unsigned int offset)
+static unsigned int ext_cap_id(unsigned int cap)
+{
+ return cap & 0xffff;
+}
+
+static unsigned int ext_cap_next_offset(unsigned int cap)
+{
+ return cap >> 20;
+}
+
+static unsigned int find_ext_cap_offset(const struct device *dev, unsigned int cap_id,
+ unsigned int offset)
{
unsigned int this_cap_offset = offset;
- unsigned int next_cap_offset, this_cap;
+
while (this_cap_offset != 0) {
- this_cap = pci_read_config32(dev, this_cap_offset);
+ const unsigned int this_cap = pci_read_config32(dev, this_cap_offset);
+
/* Bail out when this request is unsupported */
if (this_cap == 0xffffffff)
break;
- if ((this_cap & 0xffff) == cap) {
+
+ if (ext_cap_id(this_cap) == cap_id)
return this_cap_offset;
- } else {
- next_cap_offset = this_cap >> 20;
- this_cap_offset = next_cap_offset;
- }
+
+ this_cap_offset = ext_cap_next_offset(this_cap);
}
return 0;
@@ -46,11 +56,11 @@
unsigned int next_cap_offset;
if (offset)
- next_cap_offset = pci_read_config32(dev, offset) >> 20;
+ next_cap_offset = ext_cap_next_offset(pci_read_config32(dev, offset));
else
next_cap_offset = PCIE_EXT_CAP_OFFSET;
- return pciexp_get_ext_cap_offset(dev, cap, next_cap_offset);
+ return find_ext_cap_offset(dev, cap, next_cap_offset);
}
/*