pci: Add functions to update PCI configuration registers

It is common to read a config register value, clear and set some bits, then
write back the updated value. Add functions to do this in one step, for
convenience.
Signed-off-by: NSimon Glass <sjg@chromium.org>
Reviewed-by: NBin Meng <bmeng.cn@gmail.com>

drivers/pci/pci-uclass.c

@@ -250,6 +250,21 @@ int pci_bus_write_config(struct udevice *bus, pci_dev_t bdf, int offset,
 	return ops->write_config(bus, bdf, offset, value, size);
 }
 
+int pci_bus_clrset_config32(struct udevice *bus, pci_dev_t bdf, int offset,
+			    u32 clr, u32 set)
+{
+	ulong val;
+	int ret;
+
+	ret = pci_bus_read_config(bus, bdf, offset, &val, PCI_SIZE_32);
+	if (ret)
+		return ret;
+	val &= ~clr;
+	val |= set;
+
+	return pci_bus_write_config(bus, bdf, offset, val, PCI_SIZE_32);
+}
+
 int pci_write_config(pci_dev_t bdf, int offset, unsigned long value,
 		     enum pci_size_t size)
 {
@@ -418,6 +433,48 @@ int dm_pci_read_config32(struct udevice *dev, int offset, u32 *valuep)
 	return 0;
 }
 
+int dm_pci_clrset_config8(struct udevice *dev, int offset, u32 clr, u32 set)
+{
+	u8 val;
+	int ret;
+
+	ret = dm_pci_read_config8(dev, offset, &val);
+	if (ret)
+		return ret;
+	val &= ~clr;
+	val |= set;
+
+	return dm_pci_write_config8(dev, offset, val);
+}
+
+int dm_pci_clrset_config16(struct udevice *dev, int offset, u32 clr, u32 set)
+{
+	u16 val;
+	int ret;
+
+	ret = dm_pci_read_config16(dev, offset, &val);
+	if (ret)
+		return ret;
+	val &= ~clr;
+	val |= set;
+
+	return dm_pci_write_config16(dev, offset, val);
+}
+
+int dm_pci_clrset_config32(struct udevice *dev, int offset, u32 clr, u32 set)
+{
+	u32 val;
+	int ret;
+
+	ret = dm_pci_read_config32(dev, offset, &val);
+	if (ret)
+		return ret;
+	val &= ~clr;
+	val |= set;
+
+	return dm_pci_write_config32(dev, offset, val);
+}
+
 static void set_vga_bridge_bits(struct udevice *dev)
 {
 	struct udevice *parent = dev->parent;

include/pci.h

@@ -1026,6 +1026,21 @@ int pci_bus_read_config(struct udevice *bus, pci_dev_t bdf, int offset,
 int pci_bus_write_config(struct udevice *bus, pci_dev_t bdf, int offset,
 			 unsigned long value, enum pci_size_t size);
 
+/**
+ * pci_bus_clrset_config32() - Update a configuration value for a device
+ *
+ * The register at @offset is updated to (oldvalue & ~clr) | set.
+ *
+ * @bus:	Bus to access
+ * @bdf:	PCI device address: bus, device and function -see PCI_BDF()
+ * @offset:	Register offset to update
+ * @clr:	Bits to clear
+ * @set:	Bits to set
+ * @return 0 if OK, -ve on error
+ */
+int pci_bus_clrset_config32(struct udevice *bus, pci_dev_t bdf, int offset,
+			    u32 clr, u32 set);
+
 /**
  * Driver model PCI config access functions. Use these in preference to others
  * when you have a valid device
@@ -1044,6 +1059,14 @@ int dm_pci_write_config8(struct udevice *dev, int offset, u8 value);
 int dm_pci_write_config16(struct udevice *dev, int offset, u16 value);
 int dm_pci_write_config32(struct udevice *dev, int offset, u32 value);
 
+/**
+ * These permit convenient read/modify/write on PCI configuration. The
+ * register is updated to (oldvalue & ~clr) | set.
+ */
+int dm_pci_clrset_config8(struct udevice *dev, int offset, u32 clr, u32 set);
+int dm_pci_clrset_config16(struct udevice *dev, int offset, u32 clr, u32 set);
+int dm_pci_clrset_config32(struct udevice *dev, int offset, u32 clr, u32 set);
+
 /*
  * The following functions provide access to the above without needing the
  * size parameter. We are trying to encourage the use of the 8/16/32-style