1 files changed, 116 insertions, 0 deletions
diff --git a/src/soc/intel/apollolake/i2c_early.c b/src/soc/intel/apollolake/i2c_early.c
new file mode 100644
index 0000000000..968e99394a
--- /dev/null
+++ b/src/soc/intel/apollolake/i2c_early.c
@@ -0,0 +1,116 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2016 Google Inc.
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ */
+
+#include <arch/io.h>
+#include <commonlib/helpers.h>
+#include <console/console.h>
+#include <device/device.h>
+#include <device/i2c.h>
+#include <device/pci_def.h>
+#include <soc/intel/common/lpss_i2c.h>
+#include <soc/i2c.h>
+#include <soc/iomap.h>
+#include <soc/pci_devs.h>
+#include "chip.h"
+
+static int i2c_early_init_bus(unsigned bus)
+{
+	ROMSTAGE_CONST struct soc_intel_apollolake_config *config;
+	ROMSTAGE_CONST struct device *tree_dev;
+	const struct lpss_i2c_speed_config *sptr;
+	enum i2c_speed speed;
+	pci_devfn_t dev;
+	unsigned devfn;
+	uintptr_t base;
+	uint32_t value;
+	void *reg;
+
+	/* Find the PCI device for this bus controller */
+	devfn = i2c_bus_to_devfn(bus);
+	if (devfn < 0) {
+		printk(BIOS_ERR, "I2C%u device not found\n", bus);
+		return -1;
+	}
+
+	/* Look up the controller device in the devicetree */
+	dev = PCI_DEV(0, PCI_SLOT(devfn), PCI_FUNC(devfn));
+	tree_dev = dev_find_slot(0, devfn);
+	if (!tree_dev || !tree_dev->enabled) {
+		printk(BIOS_ERR, "I2C%u device not enabled\n", bus);
+		return -1;
+	}
+
+	/* Skip if not enabled for early init */
+	config = tree_dev->chip_info;
+	if (!config || !config->i2c[bus].early_init) {
+		printk(BIOS_ERR, "I2C%u not enabled for early init\n", bus);
+		return -1;
+	}
+
+	/* Prepare early base address for access before memory */
+	base = PRERAM_I2C_BASE_ADDRESS(bus);
+	pci_write_config32(dev, PCI_BASE_ADDRESS_0, base);
+	pci_write_config32(dev, PCI_COMMAND,
+			   PCI_COMMAND_MEMORY | PCI_COMMAND_MASTER);
+
+	/* Take device out of reset */
+	reg = (void *)(base + I2C_LPSS_REG_RESET);
+	value = read32(reg);
+	value |= I2C_LPSS_RESET_RELEASE_HC;
+	write32(reg, value);
+
+	/* Initialize the controller */
+	speed = config->i2c[bus].speed ? : I2C_SPEED_FAST;
+	if (lpss_i2c_init(bus, speed) < 0) {
+		printk(BIOS_ERR, "I2C%u failed to initialize\n", bus);
+		return -1;
+	}
+
+	/* Apply custom speed config if it has been set by the board */
+	for (value = 0; value < LPSS_I2C_SPEED_CONFIG_COUNT; value++) {
+		sptr = &config->i2c[bus].speed_config[value];
+		if (sptr->speed == speed) {
+			lpss_i2c_set_speed_config(bus, sptr);
+			break;
+		}
+	}
+
+	return 0;
+}
+
+uintptr_t lpss_i2c_base_address(unsigned bus)
+{
+	unsigned devfn;
+	pci_devfn_t dev;
+	uintptr_t base;
+
+	/* Find device+function for this controller */
+	devfn = i2c_bus_to_devfn(bus);
+	if (devfn < 0)
+		return (uintptr_t)NULL;
+
+	/* Form a PCI address for this device */
+	dev = PCI_DEV(0, PCI_SLOT(devfn), PCI_FUNC(devfn));
+
+	/* Read the first base address for this device */
+	base = ALIGN_DOWN(pci_read_config32(dev, PCI_BASE_ADDRESS_0), 16);
+
+	/* Attempt to initialize bus if base is not set yet */
+	if (!base && !i2c_early_init_bus(bus))
+		base = ALIGN_DOWN(pci_read_config32(dev, PCI_BASE_ADDRESS_0),
+				  16);
+
+	return base;
+}