summaryrefslogtreecommitdiff
path: root/src/drivers/i2c
diff options
context:
space:
mode:
Diffstat (limited to 'src/drivers/i2c')
-rw-r--r--src/drivers/i2c/designware/Kconfig15
-rw-r--r--src/drivers/i2c/designware/Makefile.inc8
-rw-r--r--src/drivers/i2c/designware/dw_i2c.c728
-rw-r--r--src/drivers/i2c/designware/dw_i2c.h140
4 files changed, 891 insertions, 0 deletions
diff --git a/src/drivers/i2c/designware/Kconfig b/src/drivers/i2c/designware/Kconfig
new file mode 100644
index 0000000000..e4b7777daf
--- /dev/null
+++ b/src/drivers/i2c/designware/Kconfig
@@ -0,0 +1,15 @@
+config DRIVERS_I2C_DESIGNWARE
+ bool
+ help
+ Designware I2C support
+
+config DRIVERS_I2C_DESIGNWARE_CLOCK_MHZ
+ int
+ depends on DRIVERS_I2C_DESIGNWARE
+ help
+ The i2c ip block's clock.
+
+config DRIVERS_I2C_DESIGNWARE_DEBUG
+ bool
+ default n
+ depends on DRIVERS_I2C_DESIGNWARE
diff --git a/src/drivers/i2c/designware/Makefile.inc b/src/drivers/i2c/designware/Makefile.inc
new file mode 100644
index 0000000000..0e92f05cd2
--- /dev/null
+++ b/src/drivers/i2c/designware/Makefile.inc
@@ -0,0 +1,8 @@
+ifeq ($(CONFIG_DRIVERS_I2C_DESIGNWARE),y)
+
+bootblock-y += dw_i2c.c
+romstage-y += dw_i2c.c
+verstage-y += dw_i2c.c
+ramstage-y += dw_i2c.c
+
+endif
diff --git a/src/drivers/i2c/designware/dw_i2c.c b/src/drivers/i2c/designware/dw_i2c.c
new file mode 100644
index 0000000000..75f8871d56
--- /dev/null
+++ b/src/drivers/i2c/designware/dw_i2c.c
@@ -0,0 +1,728 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2009 Vipin Kumar, ST Microelectronics
+ * Copyright 2017 Google Inc.
+ * Copyright 2017 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 <arch/acpigen.h>
+#include <arch/io.h>
+#include <console/console.h>
+#include <device/device.h>
+#include <device/i2c_simple.h>
+#include <device/pci.h>
+#include <device/pci_def.h>
+#include <device/pci_ids.h>
+#include <string.h>
+#include <timer.h>
+#include "dw_i2c.h"
+
+/* Use a ~10ms timeout for various operations */
+#define DW_I2C_TIMEOUT_US 10000
+
+/* High and low times in different speed modes (in ns) */
+enum {
+ /* SDA Hold Time */
+ DEFAULT_SDA_HOLD_TIME = 300,
+ /* Standard Speed */
+ MIN_SS_SCL_HIGHTIME = 4000,
+ MIN_SS_SCL_LOWTIME = 4700,
+ /* Fast Speed */
+ MIN_FS_SCL_HIGHTIME = 600,
+ MIN_FS_SCL_LOWTIME = 1300,
+ /* Fast Plus Speed */
+ MIN_FP_SCL_HIGHTIME = 260,
+ MIN_FP_SCL_LOWTIME = 500,
+ /* High Speed */
+ MIN_HS_SCL_HIGHTIME = 60,
+ MIN_HS_SCL_LOWTIME = 160,
+};
+
+/* Frequency represented as ticks per ns. Can also be used to calculate
+ * the number of ticks to meet a time target or the period. */
+struct freq {
+ uint32_t ticks;
+ uint32_t ns;
+};
+
+/* Control register definitions */
+enum {
+ CONTROL_MASTER_MODE = (1 << 0),
+ CONTROL_SPEED_SS = (1 << 1),
+ CONTROL_SPEED_FS = (1 << 2),
+ CONTROL_SPEED_HS = (3 << 1),
+ CONTROL_SPEED_MASK = (3 << 1),
+ CONTROL_10BIT_SLAVE = (1 << 3),
+ CONTROL_10BIT_MASTER = (1 << 4),
+ CONTROL_RESTART_ENABLE = (1 << 5),
+ CONTROL_SLAVE_DISABLE = (1 << 6),
+};
+
+/* Command/Data register definitions */
+enum {
+ CMD_DATA_CMD = (1 << 8),
+ CMD_DATA_STOP = (1 << 9),
+};
+
+/* Status register definitions */
+enum {
+ STATUS_ACTIVITY = (1 << 0),
+ STATUS_TX_FIFO_NOT_FULL = (1 << 1),
+ STATUS_TX_FIFO_EMPTY = (1 << 2),
+ STATUS_RX_FIFO_NOT_EMPTY = (1 << 3),
+ STATUS_RX_FIFO_FULL = (1 << 4),
+ STATUS_MASTER_ACTIVITY = (1 << 5),
+ STATUS_SLAVE_ACTIVITY = (1 << 6),
+};
+
+/* Enable register definitions */
+enum {
+ ENABLE_CONTROLLER = (1 << 0),
+};
+
+/* Interrupt status register definitions */
+enum {
+ INTR_STAT_RX_UNDER = (1 << 0),
+ INTR_STAT_RX_OVER = (1 << 1),
+ INTR_STAT_RX_FULL = (1 << 2),
+ INTR_STAT_TX_OVER = (1 << 3),
+ INTR_STAT_TX_EMPTY = (1 << 4),
+ INTR_STAT_RD_REQ = (1 << 5),
+ INTR_STAT_TX_ABORT = (1 << 6),
+ INTR_STAT_RX_DONE = (1 << 7),
+ INTR_STAT_ACTIVITY = (1 << 8),
+ INTR_STAT_STOP_DET = (1 << 9),
+ INTR_STAT_START_DET = (1 << 10),
+ INTR_STAT_GEN_CALL = (1 << 11),
+};
+
+/* I2C Controller MMIO register space */
+struct dw_i2c_regs {
+ uint32_t control;
+ uint32_t target_addr;
+ uint32_t slave_addr;
+ uint32_t master_addr;
+ uint32_t cmd_data;
+ uint32_t ss_scl_hcnt;
+ uint32_t ss_scl_lcnt;
+ uint32_t fs_scl_hcnt;
+ uint32_t fs_scl_lcnt;
+ uint32_t hs_scl_hcnt;
+ uint32_t hs_scl_lcnt;
+ uint32_t intr_stat;
+ uint32_t intr_mask;
+ uint32_t raw_intr_stat;
+ uint32_t rx_thresh;
+ uint32_t tx_thresh;
+ uint32_t clear_intr;
+ uint32_t clear_rx_under_intr;
+ uint32_t clear_rx_over_intr;
+ uint32_t clear_tx_over_intr;
+ uint32_t clear_rd_req_intr;
+ uint32_t clear_tx_abrt_intr;
+ uint32_t clear_rx_done_intr;
+ uint32_t clear_activity_intr;
+ uint32_t clear_stop_det_intr;
+ uint32_t clear_start_det_intr;
+ uint32_t clear_gen_call_intr;
+ uint32_t enable;
+ uint32_t status;
+ uint32_t tx_level;
+ uint32_t rx_level;
+ uint32_t sda_hold;
+ uint32_t tx_abort_source;
+ uint32_t slv_data_nak_only;
+ uint32_t dma_cr;
+ uint32_t dma_tdlr;
+ uint32_t dma_rdlr;
+ uint32_t sda_setup;
+ uint32_t ack_general_call;
+ uint32_t enable_status;
+ uint32_t fs_spklen;
+ uint32_t hs_spklen;
+ uint32_t clr_restart_det;
+ uint32_t comp_param1;
+ uint32_t comp_version;
+ uint32_t comp_type;
+} __packed;
+
+static const struct i2c_descriptor {
+ enum i2c_speed speed;
+ struct freq freq;
+ int min_thigh_ns;
+ int min_tlow_ns;
+} speed_descriptors[] = {
+ {
+ .speed = I2C_SPEED_STANDARD,
+ .freq = {
+ .ticks = 100,
+ .ns = 1000*1000,
+ },
+ .min_thigh_ns = MIN_SS_SCL_HIGHTIME,
+ .min_tlow_ns = MIN_SS_SCL_LOWTIME,
+ },
+ {
+ .speed = I2C_SPEED_FAST,
+ .freq = {
+ .ticks = 400,
+ .ns = 1000*1000,
+ },
+ .min_thigh_ns = MIN_FS_SCL_HIGHTIME,
+ .min_tlow_ns = MIN_FS_SCL_LOWTIME,
+ },
+ {
+ .speed = I2C_SPEED_FAST_PLUS,
+ .freq = {
+ .ticks = 1,
+ .ns = 1000,
+ },
+ .min_thigh_ns = MIN_FP_SCL_HIGHTIME,
+ .min_tlow_ns = MIN_FP_SCL_LOWTIME,
+ },
+ {
+ /* 100pF max capacitance */
+ .speed = I2C_SPEED_HIGH,
+ .freq = {
+ .ticks = 3400,
+ .ns = 1000*1000,
+ },
+ .min_thigh_ns = MIN_HS_SCL_HIGHTIME,
+ .min_tlow_ns = MIN_HS_SCL_LOWTIME,
+ },
+};
+
+static const struct soc_clock {
+ int clk_speed_mhz;
+ struct freq freq;
+} soc_clocks[] = {
+ {
+ .clk_speed_mhz = 120,
+ .freq = {
+ .ticks = 120,
+ .ns = 1000,
+ },
+ },
+ {
+ .clk_speed_mhz = 133,
+ .freq = {
+ .ticks = 400,
+ .ns = 3000,
+ },
+ },
+};
+
+static const struct i2c_descriptor *get_bus_descriptor(enum i2c_speed speed)
+{
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(speed_descriptors); i++)
+ if (speed == speed_descriptors[i].speed)
+ return &speed_descriptors[i];
+
+ return NULL;
+}
+
+static const struct soc_clock *get_soc_descriptor(int ic_clk)
+{
+ size_t i;
+
+ for (i = 0; i < ARRAY_SIZE(soc_clocks); i++)
+ if (ic_clk == soc_clocks[i].clk_speed_mhz)
+ return &soc_clocks[i];
+
+ return NULL;
+}
+
+static int counts_from_time(const struct freq *f, int ns)
+{
+ return DIV_ROUND_UP(f->ticks * ns, f->ns);
+}
+
+static int counts_from_freq(const struct freq *fast, const struct freq *slow)
+{
+ return DIV_ROUND_UP(fast->ticks * slow->ns, fast->ns * slow->ticks);
+}
+
+/* Enable this I2C controller */
+static void dw_i2c_enable(struct dw_i2c_regs *regs)
+{
+ uint32_t enable = read32(&regs->enable);
+
+ if (!(enable & ENABLE_CONTROLLER))
+ write32(&regs->enable, enable | ENABLE_CONTROLLER);
+}
+
+/* Disable this I2C controller */
+static int dw_i2c_disable(struct dw_i2c_regs *regs)
+{
+ uint32_t enable = read32(&regs->enable);
+
+ if (enable & ENABLE_CONTROLLER) {
+ struct stopwatch sw;
+
+ write32(&regs->enable, enable & ~ENABLE_CONTROLLER);
+
+ /* Wait for enable bit to clear */
+ stopwatch_init_usecs_expire(&sw, DW_I2C_TIMEOUT_US);
+ while (read32(&regs->enable_status) & ENABLE_CONTROLLER)
+ if (stopwatch_expired(&sw))
+ return -1;
+ }
+
+ return 0;
+}
+
+/* Wait for this I2C controller to go idle for transmit */
+static int dw_i2c_wait_for_bus_idle(struct dw_i2c_regs *regs)
+{
+ struct stopwatch sw;
+
+ /* Start timeout for up to 16 bytes in FIFO */
+ stopwatch_init_usecs_expire(&sw, 16 * DW_I2C_TIMEOUT_US);
+
+ while (!stopwatch_expired(&sw)) {
+ uint32_t status = read32(&regs->status);
+
+ /* Check for master activity and keep waiting */
+ if (status & STATUS_MASTER_ACTIVITY)
+ continue;
+
+ /* Check for TX FIFO empty to indicate TX idle */
+ if (status & STATUS_TX_FIFO_EMPTY)
+ return 0;
+ }
+
+ /* Timed out while waiting for bus to go idle */
+ return -1;
+}
+
+/* Transfer one byte of one segment, sending stop bit if requested */
+static int dw_i2c_transfer_byte(struct dw_i2c_regs *regs,
+ const struct i2c_msg *segment,
+ size_t byte, int send_stop)
+{
+ struct stopwatch sw;
+ uint32_t cmd = CMD_DATA_CMD; /* Read op */
+
+ stopwatch_init_usecs_expire(&sw, DW_I2C_TIMEOUT_US);
+
+ if (!(segment->flags & I2C_M_RD)) {
+ /* Write op only: Wait for FIFO not full */
+ while (!(read32(&regs->status) & STATUS_TX_FIFO_NOT_FULL)) {
+ if (stopwatch_expired(&sw)) {
+ printk(BIOS_ERR, "I2C transmit timeout\n");
+ return -1;
+ }
+ }
+ cmd = segment->buf[byte];
+ }
+
+ /* Send stop on last byte, if desired */
+ if (send_stop && byte == segment->len - 1)
+ cmd |= CMD_DATA_STOP;
+
+ write32(&regs->cmd_data, cmd);
+
+ if (segment->flags & I2C_M_RD) {
+ /* Read op only: Wait for FIFO data and store it */
+ while (!(read32(&regs->status) & STATUS_RX_FIFO_NOT_EMPTY)) {
+ if (stopwatch_expired(&sw)) {
+ printk(BIOS_ERR, "I2C receive timeout\n");
+ return -1;
+ }
+ }
+ segment->buf[byte] = read32(&regs->cmd_data);
+ }
+
+ return 0;
+}
+
+int dw_i2c_transfer(unsigned int bus,
+ const struct i2c_msg *segments, size_t count)
+{
+ struct stopwatch sw;
+ struct dw_i2c_regs *regs;
+ size_t byte;
+ int ret = -1;
+
+ if (count == 0 || !segments)
+ return -1;
+
+ regs = (struct dw_i2c_regs *)dw_i2c_base_address(bus);
+ if (!regs) {
+ printk(BIOS_ERR, "I2C bus %u base address not found\n", bus);
+ return -1;
+ }
+
+ dw_i2c_enable(regs);
+
+ if (dw_i2c_wait_for_bus_idle(regs)) {
+ printk(BIOS_ERR, "I2C timeout waiting for bus %u idle\n", bus);
+ goto out;
+ }
+
+ /* Process each segment */
+ while (count--) {
+ if (IS_ENABLED(CONFIG_DRIVERS_I2C_DESIGNWARE_DEBUG)) {
+ printk(BIOS_DEBUG, "i2c %u:%02x %s %d bytes : ",
+ bus, segments->slave,
+ (segments->flags & I2C_M_RD) ? "R" : "W",
+ segments->len);
+ }
+
+ /* Set target slave address */
+ write32(&regs->target_addr, segments->slave);
+
+ /* Read or write each byte in segment */
+ for (byte = 0; byte < segments->len; byte++) {
+ /*
+ * Set stop condition on final segment only.
+ * Repeated start will be automatically generated
+ * by the controller on R->W or W->R switch.
+ */
+ if (dw_i2c_transfer_byte(regs, segments, byte,
+ count == 0) < 0) {
+ printk(BIOS_ERR, "I2C %s failed: bus %u "
+ "addr 0x%02x\n",
+ (segments->flags & I2C_M_RD) ?
+ "read" : "write", bus, segments->slave);
+ goto out;
+ }
+ }
+
+ if (IS_ENABLED(CONFIG_DRIVERS_I2C_DESIGNWARE_DEBUG)) {
+ int j;
+ for (j = 0; j < segments->len; j++)
+ printk(BIOS_DEBUG, "%02x ", segments->buf[j]);
+ printk(BIOS_DEBUG, "\n");
+ }
+
+ segments++;
+ }
+
+ /* Wait for interrupt status to indicate transfer is complete */
+ stopwatch_init_usecs_expire(&sw, DW_I2C_TIMEOUT_US);
+ while (!(read32(&regs->raw_intr_stat) & INTR_STAT_STOP_DET)) {
+ if (stopwatch_expired(&sw)) {
+ printk(BIOS_ERR, "I2C stop bit not received\n");
+ goto out;
+ }
+ }
+
+ /* Read to clear INTR_STAT_STOP_DET */
+ read32(&regs->clear_stop_det_intr);
+
+ /* Wait for the bus to go idle */
+ if (dw_i2c_wait_for_bus_idle(regs)) {
+ printk(BIOS_ERR, "I2C timeout waiting for bus %u idle\n", bus);
+ goto out;
+ }
+
+ /* Flush the RX FIFO in case it is not empty */
+ stopwatch_init_usecs_expire(&sw, 16 * DW_I2C_TIMEOUT_US);
+ while (read32(&regs->status) & STATUS_RX_FIFO_NOT_EMPTY) {
+ if (stopwatch_expired(&sw)) {
+ printk(BIOS_ERR, "I2C timeout flushing RX FIFO\n");
+ goto out;
+ }
+ read32(&regs->cmd_data);
+ }
+
+ ret = 0;
+
+out:
+ read32(&regs->clear_intr);
+ dw_i2c_disable(regs);
+ return ret;
+}
+
+/* Global I2C bus handler, defined in include/device/i2c_simple.h */
+int platform_i2c_transfer(unsigned int bus, struct i2c_msg *msg, int count)
+{
+ return dw_i2c_transfer(bus, msg, count < 0 ? 0 : count);
+}
+
+static int dw_i2c_set_speed_config(unsigned int bus,
+ const struct dw_i2c_speed_config *config)
+{
+ struct dw_i2c_regs *regs;
+ void *hcnt_reg, *lcnt_reg;
+
+ regs = (struct dw_i2c_regs *)dw_i2c_base_address(bus);
+ if (!regs || !config)
+ return -1;
+
+ /* Nothing to do if no values are set */
+ if (!config->scl_lcnt && !config->scl_hcnt && !config->sda_hold)
+ return 0;
+
+ if (config->speed >= I2C_SPEED_HIGH) {
+ /* High and Fast Ultra speed */
+ hcnt_reg = &regs->hs_scl_hcnt;
+ lcnt_reg = &regs->hs_scl_lcnt;
+ } else if (config->speed >= I2C_SPEED_FAST) {
+ /* Fast and Fast-Plus speed */
+ hcnt_reg = &regs->fs_scl_hcnt;
+ lcnt_reg = &regs->fs_scl_lcnt;
+ } else {
+ /* Standard speed */
+ hcnt_reg = &regs->ss_scl_hcnt;
+ lcnt_reg = &regs->ss_scl_lcnt;
+ }
+
+ /* SCL count must be set after the speed is selected */
+ if (config->scl_hcnt)
+ write32(hcnt_reg, config->scl_hcnt);
+ if (config->scl_lcnt)
+ write32(lcnt_reg, config->scl_lcnt);
+
+ /* Set SDA Hold Time register */
+ if (config->sda_hold)
+ write32(&regs->sda_hold, config->sda_hold);
+
+ return 0;
+}
+
+static int dw_i2c_gen_config_rise_fall_time(struct dw_i2c_regs *regs,
+ enum i2c_speed speed,
+ const struct dw_i2c_bus_config *bcfg,
+ int ic_clk,
+ struct dw_i2c_speed_config *config)
+{
+ const struct i2c_descriptor *bus;
+ const struct soc_clock *soc;
+ int fall_cnt, rise_cnt, min_tlow_cnt, min_thigh_cnt, spk_cnt;
+ int hcnt, lcnt, period_cnt, diff, tot;
+ int data_hold_time_ns;
+
+ bus = get_bus_descriptor(speed);
+ soc = get_soc_descriptor(ic_clk);
+
+ if (bus == NULL) {
+ printk(BIOS_ERR, "dw_i2c: invalid bus speed %d\n", speed);
+ return -1;
+ }
+
+ if (soc == NULL) {
+ printk(BIOS_ERR, "dw_i2c: invalid SoC clock speed %d MHz\n",
+ ic_clk);
+ return -1;
+ }
+
+ /* Get the proper spike suppression count based on target speed. */
+ if (speed >= I2C_SPEED_HIGH)
+ spk_cnt = read32(&regs->hs_spklen);
+ else
+ spk_cnt = read32(&regs->fs_spklen);
+
+ /* Find the period, rise, fall, min tlow, and min thigh in terms of
+ * counts of SoC clock. */
+ period_cnt = counts_from_freq(&soc->freq, &bus->freq);
+ rise_cnt = counts_from_time(&soc->freq, bcfg->rise_time_ns);
+ fall_cnt = counts_from_time(&soc->freq, bcfg->fall_time_ns);
+ min_tlow_cnt = counts_from_time(&soc->freq, bus->min_tlow_ns);
+ min_thigh_cnt = counts_from_time(&soc->freq, bus->min_thigh_ns);
+
+ printk(DW_I2C_DEBUG, "dw_i2c: SoC %d/%d ns Bus: %d/%d ns\n",
+ soc->freq.ticks, soc->freq.ns, bus->freq.ticks, bus->freq.ns);
+ printk(DW_I2C_DEBUG,
+" dw_i2c: period %d rise %d fall %d tlow %d thigh %d spk %d\n",
+ period_cnt, rise_cnt, fall_cnt, min_tlow_cnt, min_thigh_cnt,
+ spk_cnt);
+
+ /*
+ * Back solve for hcnt and lcnt according to the following equations.
+ * SCL_High_time = [(HCNT + IC_*_SPKLEN + 7) * ic_clk] + SCL_Fall_time
+ * SCL_Low_time = [(LCNT + 1) * ic_clk] - SCL_Fall_time + SCL_Rise_time
+ */
+ hcnt = min_thigh_cnt - fall_cnt - 7 - spk_cnt;
+ lcnt = min_tlow_cnt - rise_cnt + fall_cnt - 1;
+
+ if (hcnt < 0 || lcnt < 0) {
+ printk(BIOS_ERR, "dw_i2c: bad counts. hcnt = %d lcnt = %d\n",
+ hcnt, lcnt);
+ return -1;
+ }
+
+ /* Now add things back up to ensure the period is hit. If off,
+ * split the difference and bias to lcnt for remainder. */
+ tot = hcnt + lcnt + 7 + spk_cnt + rise_cnt + 1;
+
+ if (tot < period_cnt) {
+ diff = (period_cnt - tot) / 2;
+ hcnt += diff;
+ lcnt += diff;
+ tot = hcnt + lcnt + 7 + spk_cnt + rise_cnt + 1;
+ lcnt += period_cnt - tot;
+ }
+
+ config->speed = speed;
+ config->scl_lcnt = lcnt;
+ config->scl_hcnt = hcnt;
+
+ /* Use internal default unless other value is specified. */
+ data_hold_time_ns = DEFAULT_SDA_HOLD_TIME;
+ if (bcfg->data_hold_time_ns)
+ data_hold_time_ns = bcfg->data_hold_time_ns;
+
+ config->sda_hold = counts_from_time(&soc->freq, data_hold_time_ns);
+
+ printk(DW_I2C_DEBUG, "dw_i2c: hcnt = %d lcnt = %d sda hold = %d\n",
+ hcnt, lcnt, config->sda_hold);
+
+ return 0;
+}
+
+int dw_i2c_gen_speed_config(uintptr_t dw_i2c_addr,
+ enum i2c_speed speed,
+ const struct dw_i2c_bus_config *bcfg,
+ struct dw_i2c_speed_config *config)
+{
+ const int ic_clk = CONFIG_DRIVERS_I2C_DESIGNWARE_CLOCK_MHZ;
+ struct dw_i2c_regs *regs;
+ uint16_t hcnt_min, lcnt_min;
+ int i;
+
+ regs = (struct dw_i2c_regs *)dw_i2c_addr;
+
+ _Static_assert(CONFIG_DRIVERS_I2C_DESIGNWARE_CLOCK_MHZ != 0,
+ "DRIVERS_I2C_DESIGNWARE_CLOCK_MHZ can't be zero!");
+
+ /* Apply board specific override for this speed if found */
+ for (i = 0; i < DW_I2C_SPEED_CONFIG_COUNT; i++) {
+ if (bcfg->speed_config[i].speed != speed)
+ continue;
+ memcpy(config, &bcfg->speed_config[i], sizeof(*config));
+ return 0;
+ }
+
+ /* If rise time is set use the time calculation. */
+ if (bcfg->rise_time_ns)
+ return dw_i2c_gen_config_rise_fall_time(regs, speed, bcfg,
+ ic_clk, config);
+
+ if (speed >= I2C_SPEED_HIGH) {
+ /* High speed */
+ hcnt_min = MIN_HS_SCL_HIGHTIME;
+ lcnt_min = MIN_HS_SCL_LOWTIME;
+ } else if (speed >= I2C_SPEED_FAST_PLUS) {
+ /* Fast-Plus speed */
+ hcnt_min = MIN_FP_SCL_HIGHTIME;
+ lcnt_min = MIN_FP_SCL_LOWTIME;
+ } else if (speed >= I2C_SPEED_FAST) {
+ /* Fast speed */
+ hcnt_min = MIN_FS_SCL_HIGHTIME;
+ lcnt_min = MIN_FS_SCL_LOWTIME;
+ } else {
+ /* Standard speed */
+ hcnt_min = MIN_SS_SCL_HIGHTIME;
+ lcnt_min = MIN_SS_SCL_LOWTIME;
+ }
+
+ config->speed = speed;
+ config->scl_hcnt = ic_clk * hcnt_min / KHz;
+ config->scl_lcnt = ic_clk * lcnt_min / KHz;
+ config->sda_hold = ic_clk * DEFAULT_SDA_HOLD_TIME / KHz;
+
+ return 0;
+}
+
+static int dw_i2c_set_speed(unsigned int bus, enum i2c_speed speed,
+ const struct dw_i2c_bus_config *bcfg)
+{
+ struct dw_i2c_regs *regs;
+ struct dw_i2c_speed_config config;
+ uint32_t control;
+
+ /* Clock must be provided by Kconfig */
+ regs = (struct dw_i2c_regs *)dw_i2c_base_address(bus);
+ if (!regs || !speed)
+ return -1;
+
+ control = read32(&regs->control);
+ control &= ~CONTROL_SPEED_MASK;
+
+ if (speed >= I2C_SPEED_HIGH) {
+ /* High and Fast-Ultra speed share config registers */
+ control |= CONTROL_SPEED_HS;
+ } else if (speed >= I2C_SPEED_FAST) {
+ /* Fast speed and Fast-Plus */
+ control |= CONTROL_SPEED_FS;
+ } else {
+ /* Standard speed */
+ control |= CONTROL_SPEED_SS;
+ }
+
+ /* Generate speed config based on clock */
+ if (dw_i2c_gen_speed_config((uintptr_t)regs, speed, bcfg, &config) < 0)
+ return -1;
+
+ /* Select this speed in the control register */
+ write32(&regs->control, control);
+
+ /* Write the speed config that was generated earlier */
+ dw_i2c_set_speed_config(bus, &config);
+
+ return 0;
+}
+
+
+/*
+ * Initialize this bus controller and set the speed.
+ *
+ * The bus speed can be passed in Hz or using values from device/i2c.h and
+ * will default to I2C_SPEED_FAST if it is not provided.
+ */
+int dw_i2c_init(unsigned int bus, const struct dw_i2c_bus_config *bcfg)
+{
+ struct dw_i2c_regs *regs;
+ enum i2c_speed speed;
+
+ if (!bcfg)
+ return -1;
+
+ speed = bcfg->speed ? : I2C_SPEED_FAST;
+
+ regs = (struct dw_i2c_regs *)dw_i2c_base_address(bus);
+ if (!regs) {
+ printk(BIOS_ERR, "I2C bus %u base address not found\n", bus);
+ return -1;
+ }
+
+ if (dw_i2c_disable(regs) < 0) {
+ printk(BIOS_ERR, "I2C timeout disabling bus %u\n", bus);
+ return -1;
+ }
+
+ /* Put controller in master mode with restart enabled */
+ write32(&regs->control, CONTROL_MASTER_MODE | CONTROL_SLAVE_DISABLE |
+ CONTROL_RESTART_ENABLE);
+
+ /* Set bus speed to FAST by default */
+ if (dw_i2c_set_speed(bus, speed, bcfg) < 0) {
+ printk(BIOS_ERR, "I2C failed to set speed for bus %u\n", bus);
+ return -1;
+ }
+
+ /* Set RX/TX thresholds to smallest values */
+ write32(&regs->rx_thresh, 0);
+ write32(&regs->tx_thresh, 0);
+
+ /* Enable stop detection interrupt */
+ write32(&regs->intr_mask, INTR_STAT_STOP_DET);
+
+ printk(BIOS_INFO, "DW I2C bus %u at 0x%p (%u KHz)\n",
+ bus, regs, speed / KHz);
+
+ return 0;
+}
diff --git a/src/drivers/i2c/designware/dw_i2c.h b/src/drivers/i2c/designware/dw_i2c.h
new file mode 100644
index 0000000000..8fea4e1c9b
--- /dev/null
+++ b/src/drivers/i2c/designware/dw_i2c.h
@@ -0,0 +1,140 @@
+/*
+ * This file is part of the coreboot project.
+ *
+ * Copyright 2017 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 imfamiluarplied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ */
+
+#ifndef __DRIVERS_I2C_DESIGNWARE_I2C_H__
+#define __DRIVERS_I2C_DESIGNWARE_I2C_H__
+
+#include <compiler.h>
+#include <device/device.h>
+#include <device/i2c.h>
+#include <stdint.h>
+
+#if IS_ENABLED(CONFIG_DRIVERS_I2C_DESIGNWARE_DEBUG)
+#define DW_I2C_DEBUG BIOS_DEBUG
+
+#else
+#define DW_I2C_DEBUG BIOS_NEVER
+
+#endif // CONFIG_DRIVERS_I2C_DESIGNWARE_DEBUG
+
+/*
+ * Timing values are in units of clock period, with the clock speed
+ * provided by the SOC in CONFIG_DRIVERS_I2C_DESIGNWARE_I2C_CLOCK_MHZ
+ * Automatic configuration is done based on requested speed, but the
+ * values may need tuned depending on the board and the number of
+ * devices present on the bus.
+ */
+struct dw_i2c_speed_config {
+ enum i2c_speed speed;
+ /* SCL high and low period count */
+ uint16_t scl_lcnt;
+ uint16_t scl_hcnt;
+ /*
+ * SDA hold time should be 300ns in standard and fast modes
+ * and long enough for deterministic logic level change in
+ * fast-plus and high speed modes.familuar
+ *
+ * [15:0] SDA TX Hold Time
+ * [23:16] SDA RX Hold Time
+ */
+ uint32_t sda_hold;
+};
+
+/*
+ * This I2C controller has support for 3 independent speed configs but can
+ * support both FAST_PLUS and HIGH speeds through the same set of speed
+ * config registers. These are treated separately so the speed config values
+ * can be provided via ACPI to the OS.
+ */
+#define DW_I2C_SPEED_CONFIG_COUNT 4
+
+struct dw_i2c_bus_config {
+ /* Bus should be enabled prior to ramstage with temporary base */
+ int early_init;
+ /* Bus speed in Hz, default is I2C_SPEED_FAST (400 KHz) */
+ enum i2c_speed speed;
+ /* If rise_time_ns is non-zero the calculations for lcnt and hcnt
+ * registers take into account the times of the bus. However, if
+ * there is a match in speed_config those register values take
+ * precedence. */
+ int rise_time_ns;
+ int fall_time_ns;
+ int data_hold_time_ns;
+ /* Specific bus speed configuration */
+ struct dw_i2c_speed_config speed_config[DW_I2C_SPEED_CONFIG_COUNT];
+};
+
+/* Functions to be implemented by SoC code */
+
+/* Get base address for early init of I2C controllers. */
+uintptr_t i2c_get_soc_early_base(unsigned int bus);
+
+/*
+ * Map given I2C bus number to devfn.
+ * Return value:
+ * -1 = error
+ * otherwise, devfn(>=0) corresponding to I2C bus number.
+ */
+int i2c_soc_devfn_to_bus(unsigned int devfn);
+
+/*
+ * Map given bus number to a I2C Controller.
+ * Return value:
+ * -1 = error
+ * otherwise, devfn(>=0) corresponding to I2C bus number.
+ */
+int i2c_soc_bus_to_devfn(unsigned int bus);
+
+/*
+ * SoC implemented callback for getting I2C bus configuration.
+ *
+ * Returns NULL if i2c config is not found
+ */
+const struct dw_i2c_bus_config *i2c_get_soc_cfg(unsigned int bus,
+ const struct device *dev);
+
+/* Get I2C controller base address */
+uintptr_t dw_i2c_base_address(unsigned int bus);
+
+/*
+ * Initialize this bus controller and set the speed
+ * Return value:
+ * -1 = failure
+ * 0 = success
+*/
+int dw_i2c_init(unsigned int bus, const struct dw_i2c_bus_config *bcfg);
+
+/*
+ * Generate speed config based on clock
+ * Return value:
+ * -1 = failure
+ * 0 = success
+*/
+int dw_i2c_gen_speed_config(uintptr_t dw_i2c_addr,
+ enum i2c_speed speed,
+ const struct dw_i2c_bus_config *bcfg,
+ struct dw_i2c_speed_config *config);
+
+/*
+ * Process given I2C segments in a single transfer
+ * Return value:
+ * -1 = failure
+ * 0 = success
+ */
+int dw_i2c_transfer(unsigned int bus,
+ const struct i2c_msg *segments,
+ size_t count);
+
+#endif /* __DRIVERS_I2C_DESIGNWARE_I2C_H__ */