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-rw-r--r--payloads/libpayload/drivers/pci.c8
-rw-r--r--payloads/libpayload/include/pci.h6
2 files changed, 13 insertions, 1 deletions
diff --git a/payloads/libpayload/drivers/pci.c b/payloads/libpayload/drivers/pci.c
index fc1940afbc..be92613e88 100644
--- a/payloads/libpayload/drivers/pci.c
+++ b/payloads/libpayload/drivers/pci.c
@@ -112,3 +112,11 @@ u32 pci_read_resource(pcidev_t dev, int bar)
{
return pci_read_config32(dev, 0x10 + (bar * 4));
}
+
+void pci_set_bus_master(pcidev_t dev)
+{
+ u16 val = pci_read_config16(dev, REG_COMMAND);
+ val |= REG_COMMAND_BM;
+ pci_write_config16(dev, REG_COMMAND, val);
+}
+
diff --git a/payloads/libpayload/include/pci.h b/payloads/libpayload/include/pci.h
index 1b51f8cd78..93d1267ef5 100644
--- a/payloads/libpayload/include/pci.h
+++ b/payloads/libpayload/include/pci.h
@@ -35,10 +35,12 @@
typedef u32 pcidev_t;
#define REG_VENDOR_ID 0x00
-#define REG_DEVICE_ID 0x04
+#define REG_COMMAND 0x04
#define REG_HEADER_TYPE 0x0E
#define REG_PRIMARY_BUS 0x18
+#define REG_COMMAND_BM (1 << 2)
+
#define HEADER_TYPE_NORMAL 0
#define HEADER_TYPE_BRIDGE 1
#define HEADER_TYPE_CARDBUS 2
@@ -64,4 +66,6 @@ void pci_write_config32(u32 device, u16 reg, u32 val);
int pci_find_device(u16 vid, u16 did, pcidev_t *dev);
u32 pci_read_resource(pcidev_t dev, int bar);
+void pci_set_bus_master(pcidev_t dev);
+
#endif