Helper function to set/clear specific bit in PCI_COMMAND register.
Signed-off-by: Peter Xu <peterx@xxxxxxxxxx>
---
lib/pci.c | 12 ++++++++++++
lib/pci.h | 1 +
2 files changed, 13 insertions(+)
diff --git a/lib/pci.c b/lib/pci.c
index c063d53..fd17ea5 100644
--- a/lib/pci.c
+++ b/lib/pci.c
@@ -7,6 +7,18 @@
#include "pci.h"
#include "asm/pci.h"
+void pci_cmd_set_clr(struct pci_dev *dev, uint16_t set, uint16_t clr)
+{
+ uint16_t val = pci_config_readw(dev->bdf, PCI_COMMAND);
+
+ /* No overlap is allowed */
+ assert((set & clr) == 0);
+ val |= set;
+ val &= ~clr;
+
+ pci_config_writew(dev->bdf, PCI_COMMAND, val);
+}
+
bool pci_dev_exists(pcidevaddr_t dev)
{
return (pci_config_readw(dev, PCI_VENDOR_ID) != 0xffff &&
diff --git a/lib/pci.h b/lib/pci.h
index e452819..de15086 100644
--- a/lib/pci.h
+++ b/lib/pci.h
@@ -25,6 +25,7 @@ struct pci_dev {
void pci_dev_init(struct pci_dev *dev, pcidevaddr_t bdf);
void pci_scan_bars(struct pci_dev *dev);
+void pci_cmd_set_clr(struct pci_dev *dev, uint16_t set, uint16_t clr);
extern bool pci_probe(void);
extern void pci_print(void);
--
2.7.4
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