diff options
Diffstat (limited to 'src/drivers/i2c')
| -rw-r--r-- | src/drivers/i2c/designware/Kconfig | 15 | ||||
| -rw-r--r-- | src/drivers/i2c/designware/Makefile.inc | 8 | ||||
| -rw-r--r-- | src/drivers/i2c/designware/dw_i2c.c | 728 | ||||
| -rw-r--r-- | src/drivers/i2c/designware/dw_i2c.h | 140 |
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(®s->enable); + + if (!(enable & ENABLE_CONTROLLER)) + write32(®s->enable, enable | ENABLE_CONTROLLER); +} + +/* Disable this I2C controller */ +static int dw_i2c_disable(struct dw_i2c_regs *regs) +{ + uint32_t enable = read32(®s->enable); + + if (enable & ENABLE_CONTROLLER) { + struct stopwatch sw; + + write32(®s->enable, enable & ~ENABLE_CONTROLLER); + + /* Wait for enable bit to clear */ + stopwatch_init_usecs_expire(&sw, DW_I2C_TIMEOUT_US); + while (read32(®s->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(®s->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(®s->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(®s->cmd_data, cmd); + + if (segment->flags & I2C_M_RD) { + /* Read op only: Wait for FIFO data and store it */ + while (!(read32(®s->status) & STATUS_RX_FIFO_NOT_EMPTY)) { + if (stopwatch_expired(&sw)) { + printk(BIOS_ERR, "I2C receive timeout\n"); + return -1; + } + } + segment->buf[byte] = read32(®s->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(®s->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(®s->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(®s->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(®s->status) & STATUS_RX_FIFO_NOT_EMPTY) { + if (stopwatch_expired(&sw)) { + printk(BIOS_ERR, "I2C timeout flushing RX FIFO\n"); + goto out; + } + read32(®s->cmd_data); + } + + ret = 0; + +out: + read32(®s->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 = ®s->hs_scl_hcnt; + lcnt_reg = ®s->hs_scl_lcnt; + } else if (config->speed >= I2C_SPEED_FAST) { + /* Fast and Fast-Plus speed */ + hcnt_reg = ®s->fs_scl_hcnt; + lcnt_reg = ®s->fs_scl_lcnt; + } else { + /* Standard speed */ + hcnt_reg = ®s->ss_scl_hcnt; + lcnt_reg = ®s->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(®s->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(®s->hs_spklen); + else + spk_cnt = read32(®s->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(®s->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(®s->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(®s->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(®s->rx_thresh, 0); + write32(®s->tx_thresh, 0); + + /* Enable stop detection interrupt */ + write32(®s->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__ */ |