soc/intel/quark: Add I2C support

Add the I2C driver.

TEST=Build and run on Galileo Gen2

Change-Id: I53fdac93667a8ffb2c2c8f394334de2dece63d66
Signed-off-by: Lee Leahy <leroy.p.leahy@intel.com>
Reviewed-on: https://review.coreboot.org/14828
Tested-by: build bot (Jenkins)
Reviewed-by: Martin Roth <martinroth@google.com>

src/soc/intel/quark/gpio_i2c.c

@@ -0,0 +1,195 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright (C) 2016 Intel Corporation.
+ *
+ * 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 <console/console.h>
+#include <delay.h>
+#include <device/device.h>
+#include <device/i2c.h>
+#include <device/pci.h>
+#include <device/pci_ids.h>
+#include <soc/i2c.h>
+#include <soc/ramstage.h>
+#include <soc/reg_access.h>
+
+static void i2c_disable(I2C_REGS *regs)
+{
+	uint32_t status;
+	uint32_t timeout;
+
+	/* Disable I2C controller */
+	regs->ic_enable = 0;
+
+	/* Wait for the enable bit to clear */
+	timeout = 1 * 1000 * 1000;
+	status = regs->ic_enable_status;
+	while (status & IC_ENABLE_CONTROLLER) {
+		udelay(1);
+		if (--timeout == 0)
+			die("ERROR - I2C failed to disable!\n");
+		status = regs->ic_enable_status;
+	}
+
+	/* Clear any pending interrupts */
+	status = regs->ic_clr_intr;
+}
+
+int platform_i2c_transfer(unsigned bus, struct i2c_seg *segments, int count)
+{
+	uint8_t *buffer;
+	int bytes_transferred;
+	uint8_t chip;
+	uint32_t cmd;
+	int length;
+	int read_length;
+	I2C_REGS *regs;
+	uint32_t status;
+	uint32_t timeout;
+
+	regs = get_i2c_address();
+
+	/* Disable the I2C controller to get access to the registers */
+	i2c_disable(regs);
+
+	/* Set the slave address */
+	ASSERT (count > 0);
+	ASSERT (segments != NULL);
+	ASSERT (segments->read == 0);
+
+	/* Clear the start and stop detection */
+	status = regs->ic_clr_start_det;
+	status = regs->ic_clr_stop_det;
+
+	/* Set addressing mode to 7-bit and fast mode */
+	cmd = regs->ic_con;
+	cmd &= ~(IC_CON_10B | IC_CON_SPEED);
+	cmd |= IC_CON_RESTART_EN | IC_CON_7B | IC_CON_SPEED_100_KHz
+		| IC_CON_MASTER_MODE;
+	regs->ic_con = cmd;
+
+	/* Set the target chip address */
+	chip = segments->chip;
+	regs->ic_tar = chip;
+
+	/* Enable the I2C controller */
+	regs->ic_enable = IC_ENABLE_CONTROLLER;
+
+	/* Clear the interrupts */
+	status = regs->ic_clr_rx_under;
+	status = regs->ic_clr_rx_over;
+	status = regs->ic_clr_tx_over;
+	status = regs->ic_clr_tx_abrt;
+
+	/* Process each of the segments */
+	bytes_transferred = 0;
+	read_length = 0;
+	buffer = NULL;
+	while (count-- > 0) {
+		buffer = segments->buf;
+		length = segments->len;
+		ASSERT (buffer != NULL);
+		ASSERT (length >= 1);
+		ASSERT (segments->chip = chip);
+
+		if (segments->read) {
+			/* Place read commands into the FIFO */
+			read_length = length;
+			while (length > 0) {
+				/* Send stop bit after last byte */
+				cmd = IC_DATA_CMD_READ;
+				if ((count == 0) && (length == 1))
+					cmd |= IC_DATA_CMD_STOP;
+
+				/* Place read command in transmit FIFO */
+				regs->ic_data_cmd = cmd;
+				length--;
+			}
+		} else {
+			/* Write the data into the FIFO */
+			while (length > 0) {
+				/* End of the transaction? */
+				cmd = IC_DATA_CMD_WRITE | *buffer++;
+				if ((count == 0) && (length == 1))
+					cmd |= IC_DATA_CMD_STOP;
+
+				/* Place a data byte into the FIFO */
+				regs->ic_data_cmd = cmd;
+				length--;
+				bytes_transferred++;
+			}
+		}
+		segments++;
+	}
+
+	/* Wait for the end of the transaction */
+	timeout = 1 * 1000 * 1000;
+	do {
+		status = regs->ic_raw_intr_stat;
+		if (status & IC_INTR_STOP_DET)
+			break;
+		if ((status & (IC_INTR_RX_OVER | IC_INTR_RX_UNDER
+				| IC_INTR_TX_ABRT | IC_INTR_TX_OVER))
+			|| (timeout == 0)) {
+			if (timeout == 0)
+				printk (BIOS_ERR,
+					"ERROR - I2C stop bit not received!\n");
+			if (status & IC_INTR_RX_OVER)
+				printk (BIOS_ERR,
+					"ERROR - I2C receive overrun!\n");
+			if (status & IC_INTR_RX_UNDER)
+				printk (BIOS_ERR,
+					"ERROR - I2C receive underrun!\n");
+			if (status & IC_INTR_TX_ABRT)
+				printk (BIOS_ERR,
+					"ERROR - I2C transmit abort!\n");
+			if (status & IC_INTR_TX_OVER)
+				printk (BIOS_ERR,
+					"ERROR - I2C transmit overrun!\n");
+			i2c_disable(regs);
+			return -1;
+		}
+		timeout--;
+		udelay(1);
+	} while(1);
+
+	/* Finish reading the data bytes */
+	while (read_length > 0) {
+		status = regs->ic_status;
+		*buffer++ = (UINT8)regs->ic_data_cmd;
+		read_length--;
+		bytes_transferred++;
+		status = regs->ic_status;
+	}
+
+	return bytes_transferred;
+}
+
+__attribute__((weak)) void mainboard_gpio_i2c_init(device_t dev)
+{
+	/* Initialize any of the GPIOs or I2C devices */
+	printk(BIOS_SPEW, "WEAK; mainboard_gpio_i2c_init\n");
+}
+
+static struct device_operations device_ops = {
+	.read_resources		= pci_dev_read_resources,
+	.set_resources		= pci_dev_set_resources,
+	.enable_resources	= pci_dev_enable_resources,
+	.init			= mainboard_gpio_i2c_init,
+};
+
+static const struct pci_driver gfx_driver __pci_driver = {
+	.ops	= &device_ops,
+	.vendor	= PCI_VENDOR_ID_INTEL,
+	.device	= I2CGPIO_DEVID,
+};