[SeaBIOS] [PATCH] pci: capability scanning function
Michael S. Tsirkin
mst at redhat.com
Wed Jul 6 16:03:21 CEST 2011
Add pci_find_capability to scan capability list.
Return 0 on error, capability offset if found.
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
---
Not useful by itself, but should be handy if
we ever want to look at capabilities such as pci express.
diff --git a/src/pci.c b/src/pci.c
index 23a6878..324ac96 100644
--- a/src/pci.c
+++ b/src/pci.c
@@ -57,6 +57,30 @@ pci_config_maskw(u16 bdf, u32 addr, u16 off, u16 on)
pci_config_writew(bdf, addr, val);
}
+unsigned char pci_find_capability(u16 bdf, unsigned char cap_id)
+{
+ unsigned char next, prev;
+ int loop = 0;
+
+ if (!(pci_config_readb(bdf, PCI_STATUS) & PCI_STATUS_CAP_LIST))
+ return 0;
+
+ for (prev = PCI_CAPABILITY_LIST; (next = pci_config_readb(bdf, prev));
+ prev = next + PCI_CAP_LIST_NEXT) {
+ if (pci_config_readb(bdf, next + PCI_CAP_LIST_ID) == cap_id)
+ break;
+ if (loop++ > 0x100) {
+ dprintf(1, "ERROR: capability loop detected. "
+ "PCI device %02x:%02x.%x\n"
+ , pci_bdf_to_bus(bdf), pci_bdf_to_dev(bdf)
+ , pci_bdf_to_fn(bdf));
+ return 0;
+ }
+ }
+
+ return next;
+}
+
// Helper function for foreachbdf() macro - return next device
int
pci_next(int bdf, int bus)
diff --git a/src/pci.h b/src/pci.h
index c34e348..160cfc1 100644
--- a/src/pci.h
+++ b/src/pci.h
@@ -110,6 +110,8 @@ void pci_reboot(void);
u32 pci_readl(u32 addr);
void pci_writel(u32 addr, u32 val);
+unsigned char pci_find_capability(u16 bdf, unsigned char cap_id);
+
// pirtable.c
void create_pirtable(void);
--
MST
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