x86: ivybridge: Add early LPC init so that serial works
The PCH (Platform Controller Hub) includes an LPC (Low Pin Count) device
which provides a serial port. This is accessible on Chromebooks, so enable
it early in the boot process.
Signed-off-by: Simon Glass <sjg@chromium.org>
diff --git a/arch/x86/cpu/ivybridge/lpc.c b/arch/x86/cpu/ivybridge/lpc.c
new file mode 100644
index 0000000..621ef2c
--- /dev/null
+++ b/arch/x86/cpu/ivybridge/lpc.c
@@ -0,0 +1,48 @@
+/*
+ * From coreboot southbridge/intel/bd82x6x/lpc.c
+ *
+ * Copyright (C) 2008-2009 coresystems GmbH
+ *
+ * SPDX-License-Identifier: GPL-2.0
+ */
+
+#include <common.h>
+#include <errno.h>
+#include <fdtdec.h>
+#include <pci.h>
+#include <asm/pci.h>
+#include <asm/arch/pch.h>
+
+int lpc_early_init(const void *blob, int node, pci_dev_t dev)
+{
+ struct reg_info {
+ u32 base;
+ u32 size;
+ } values[4], *ptr;
+ int count;
+ int i;
+
+ count = fdtdec_get_int_array_count(blob, node, "gen-dec",
+ (u32 *)values, sizeof(values) / sizeof(u32));
+ if (count < 0)
+ return -EINVAL;
+
+ /* Set COM1/COM2 decode range */
+ pci_write_config16(dev, LPC_IO_DEC, 0x0010);
+
+ /* Enable PS/2 Keyboard/Mouse, EC areas and COM1 */
+ pci_write_config16(dev, LPC_EN, KBC_LPC_EN | MC_LPC_EN |
+ GAMEL_LPC_EN | COMA_LPC_EN);
+
+ /* Write all registers but use 0 if we run out of data */
+ count = count * sizeof(u32) / sizeof(values[0]);
+ for (i = 0, ptr = values; i < ARRAY_SIZE(values); i++, ptr++) {
+ u32 reg = 0;
+
+ if (i < count)
+ reg = ptr->base | PCI_COMMAND_IO | (ptr->size << 16);
+ pci_write_config32(dev, LPC_GENX_DEC(i), reg);
+ }
+
+ return 0;
+}