x86: broadwell: Add an LPC driver

Add a driver for the broadwell LPC (low-pin-count peripheral). This mostly
uses common code.

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

2 files changed, 78 insertions, 0 deletions

diff --git a/arch/x86/cpu/broadwell/Makefile b/arch/x86/cpu/broadwell/Makefile
index 39bf73395db..3054a89165f 100644
--- a/arch/x86/cpu/broadwell/Makefile
+++ b/arch/x86/cpu/broadwell/Makefile
@@ -6,6 +6,7 @@
 
 obj-y += cpu.o
 obj-y += iobp.o
+obj-y += lpc.o
 obj-y += northbridge.o
 obj-y += pch.o
 obj-y += pinctrl_broadwell.o
diff --git a/arch/x86/cpu/broadwell/lpc.c b/arch/x86/cpu/broadwell/lpc.c
new file mode 100644
index 00000000000..ee3ac1820de
--- /dev/null
+++ b/arch/x86/cpu/broadwell/lpc.c
@@ -0,0 +1,77 @@
+/*
+ * Copyright (c) 2016 Google, Inc
+ *
+ * From coreboot broadwell support
+ *
+ * SPDX-License-Identifier:	GPL-2.0
+ */
+
+#include <common.h>
+#include <dm.h>
+#include <pch.h>
+#include <asm/intel_regs.h>
+#include <asm/io.h>
+#include <asm/lpc_common.h>
+#include <asm/arch/pch.h>
+#include <asm/arch/spi.h>
+
+static void set_spi_speed(void)
+{
+	u32 fdod;
+	u8 ssfc;
+
+	/* Observe SPI Descriptor Component Section 0 */
+	writel(0x1000, SPI_REG(SPIBAR_FDOC));
+
+	/* Extract the Write/Erase SPI Frequency from descriptor */
+	fdod = readl(SPI_REG(SPIBAR_FDOD));
+	fdod >>= 24;
+	fdod &= 7;
+
+	/* Set Software Sequence frequency to match */
+	ssfc = readb(SPI_REG(SPIBAR_SSFC + 2));
+	ssfc &= ~7;
+	ssfc |= fdod;
+	writeb(ssfc, SPI_REG(SPIBAR_SSFC + 2));
+}
+
+static int broadwell_lpc_early_init(struct udevice *dev)
+{
+	set_spi_speed();
+
+	return 0;
+}
+
+static int lpc_init_extra(struct udevice *dev)
+{
+	return 0;
+}
+
+static int broadwell_lpc_probe(struct udevice *dev)
+{
+	int ret;
+
+	if (!(gd->flags & GD_FLG_RELOC)) {
+		ret = lpc_common_early_init(dev);
+		if (ret) {
+			debug("%s: lpc_early_init() failed\n", __func__);
+			return ret;
+		}
+
+		return broadwell_lpc_early_init(dev);
+	}
+
+	return lpc_init_extra(dev);
+}
+
+static const struct udevice_id broadwell_lpc_ids[] = {
+	{ .compatible = "intel,broadwell-lpc" },
+	{ }
+};
+
+U_BOOT_DRIVER(broadwell_lpc_drv) = {
+	.name		= "lpc",
+	.id		= UCLASS_LPC,
+	.of_match	= broadwell_lpc_ids,
+	.probe		= broadwell_lpc_probe,
+};