dm: x86: Add a driver for Intel PCH7

At some point we may need to distinguish between different types of PCHs,
but for existing supported platforms we only need to worry about version 7
and version 9 bridges. Add a driver for the PCH7.

Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

drivers/pch/Makefile

@@ -3,3 +3,4 @@
 #
 
 obj-y += pch-uclass.o
+obj-y += pch7.o

drivers/pch/pch7.c

@@ -0,0 +1,61 @@
+/*
+ * Copyright (C) 2014 Google, Inc
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <pch.h>
+
+#define BIOS_CTRL	0xd8
+
+static int pch7_get_sbase(struct udevice *dev, ulong *sbasep)
+{
+	u32 rcba;
+
+	dm_pci_read_config32(dev, PCH_RCBA, &rcba);
+	/* Bits 31-14 are the base address, 13-1 are reserved, 0 is enable */
+	rcba = rcba & 0xffffc000;
+	*sbasep = rcba + 0x3020;
+
+	return 0;
+}
+
+static enum pch_version pch7_get_version(struct udevice *dev)
+{
+	return PCHV_7;
+}
+
+static int pch7_set_spi_protect(struct udevice *dev, bool protect)
+{
+	uint8_t bios_cntl;
+
+	/* Adjust the BIOS write protect to dis/allow write commands */
+	dm_pci_read_config8(dev, BIOS_CTRL, &bios_cntl);
+	if (protect)
+		bios_cntl &= ~BIOS_CTRL_BIOSWE;
+	else
+		bios_cntl |= BIOS_CTRL_BIOSWE;
+	dm_pci_write_config8(dev, BIOS_CTRL, bios_cntl);
+
+	return 0;
+}
+
+static const struct pch_ops pch7_ops = {
+	.get_sbase	= pch7_get_sbase,
+	.get_version	= pch7_get_version,
+	.set_spi_protect = pch7_set_spi_protect,
+};
+
+static const struct udevice_id pch7_ids[] = {
+	{ .compatible = "intel,pch7" },
+	{ }
+};
+
+U_BOOT_DRIVER(pch7_drv) = {
+	.name		= "intel-pch7",
+	.id		= UCLASS_PCH,
+	.of_match	= pch7_ids,
+	.ops		= &pch7_ops,
+};

include/pch.h

@@ -14,6 +14,10 @@ enum pch_version {
 	PCHV_9,
 };
 
+#define PCH_RCBA		0xf0
+
+#define BIOS_CTRL_BIOSWE	BIT(0)
+
 /* Operations for the Platform Controller Hub */
 struct pch_ops {
 	/**