--- /dev/null
+/*
+ * Copyright (C) 2018 Marvell International Ltd.
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ * https://spdx.org/licenses
+ */
+
+/* This driver provides I2C support for Marvell A8K and compatible SoCs */
+
+#include <a8k_i2c.h>
+#include <debug.h>
+#include <delay_timer.h>
+#include <errno.h>
+#include <mmio.h>
+#include <mvebu_def.h>
+
+#if LOG_LEVEL >= LOG_LEVEL_VERBOSE
+#define DEBUG_I2C
+#endif
+
+#define CONFIG_SYS_TCLK 250000000
+#define CONFIG_SYS_I2C_SPEED 100000
+#define CONFIG_SYS_I2C_SLAVE 0x0
+#define I2C_TIMEOUT_VALUE 0x500
+#define I2C_MAX_RETRY_CNT 1000
+#define I2C_CMD_WRITE 0x0
+#define I2C_CMD_READ 0x1
+
+#define I2C_DATA_ADDR_7BIT_OFFS 0x1
+#define I2C_DATA_ADDR_7BIT_MASK (0xFF << I2C_DATA_ADDR_7BIT_OFFS)
+
+#define I2C_CONTROL_ACK 0x00000004
+#define I2C_CONTROL_IFLG 0x00000008
+#define I2C_CONTROL_STOP 0x00000010
+#define I2C_CONTROL_START 0x00000020
+#define I2C_CONTROL_TWSIEN 0x00000040
+#define I2C_CONTROL_INTEN 0x00000080
+
+#define I2C_STATUS_START 0x08
+#define I2C_STATUS_REPEATED_START 0x10
+#define I2C_STATUS_ADDR_W_ACK 0x18
+#define I2C_STATUS_DATA_W_ACK 0x28
+#define I2C_STATUS_LOST_ARB_DATA_ADDR_TRANSFER 0x38
+#define I2C_STATUS_ADDR_R_ACK 0x40
+#define I2C_STATUS_DATA_R_ACK 0x50
+#define I2C_STATUS_DATA_R_NAK 0x58
+#define I2C_STATUS_LOST_ARB_GENERAL_CALL 0x78
+#define I2C_STATUS_IDLE 0xF8
+
+#define I2C_UNSTUCK_TRIGGER 0x1
+#define I2C_UNSTUCK_ONGOING 0x2
+#define I2C_UNSTUCK_ERROR 0x4
+struct marvell_i2c_regs {
+ uint32_t slave_address;
+ uint32_t data;
+ uint32_t control;
+ union {
+ uint32_t status; /* when reading */
+ uint32_t baudrate; /* when writing */
+ } u;
+ uint32_t xtnd_slave_addr;
+ uint32_t reserved[2];
+ uint32_t soft_reset;
+ uint8_t reserved2[0xa0 - 0x20];
+ uint32_t unstuck;
+};
+
+static struct marvell_i2c_regs *base;
+
+static int marvell_i2c_lost_arbitration(uint32_t *status)
+{
+ *status = mmio_read_32((uintptr_t)&base->u.status);
+ if ((*status == I2C_STATUS_LOST_ARB_DATA_ADDR_TRANSFER) ||
+ (*status == I2C_STATUS_LOST_ARB_GENERAL_CALL))
+ return -EAGAIN;
+
+ return 0;
+}
+
+static void marvell_i2c_interrupt_clear(void)
+{
+ uint32_t reg;
+
+ reg = mmio_read_32((uintptr_t)&base->control);
+ reg &= ~(I2C_CONTROL_IFLG);
+ mmio_write_32((uintptr_t)&base->control, reg);
+ /* Wait for 1 us for the clear to take effect */
+ udelay(1);
+}
+
+static int marvell_i2c_interrupt_get(void)
+{
+ uint32_t reg;
+
+ /* get the interrupt flag bit */
+ reg = mmio_read_32((uintptr_t)&base->control);
+ reg &= I2C_CONTROL_IFLG;
+ return reg && I2C_CONTROL_IFLG;
+}
+
+static int marvell_i2c_wait_interrupt(void)
+{
+ uint32_t timeout = 0;
+
+ while (!marvell_i2c_interrupt_get() && (timeout++ < I2C_TIMEOUT_VALUE))
+ ;
+ if (timeout >= I2C_TIMEOUT_VALUE)
+ return -ETIMEDOUT;
+
+ return 0;
+}
+
+static int marvell_i2c_start_bit_set(void)
+{
+ int is_int_flag = 0;
+ uint32_t status;
+
+ if (marvell_i2c_interrupt_get())
+ is_int_flag = 1;
+
+ /* set start bit */
+ mmio_write_32((uintptr_t)&base->control,
+ mmio_read_32((uintptr_t)&base->control) |
+ I2C_CONTROL_START);
+
+ /* in case that the int flag was set before i.e. repeated start bit */
+ if (is_int_flag) {
+ VERBOSE("%s: repeated start Bit\n", __func__);
+ marvell_i2c_interrupt_clear();
+ }
+
+ if (marvell_i2c_wait_interrupt()) {
+ ERROR("Start clear bit timeout\n");
+ return -ETIMEDOUT;
+ }
+
+ /* check that start bit went down */
+ if ((mmio_read_32((uintptr_t)&base->control) &
+ I2C_CONTROL_START) != 0) {
+ ERROR("Start bit didn't went down\n");
+ return -EPERM;
+ }
+
+ /* check the status */
+ if (marvell_i2c_lost_arbitration(&status)) {
+ ERROR("%s - %d: Lost arbitration, got status %x\n",
+ __func__, __LINE__, status);
+ return -EAGAIN;
+ }
+ if ((status != I2C_STATUS_START) &&
+ (status != I2C_STATUS_REPEATED_START)) {
+ ERROR("Got status %x after enable start bit.\n", status);
+ return -EPERM;
+ }
+
+ return 0;
+}
+
+static int marvell_i2c_stop_bit_set(void)
+{
+ int timeout;
+ uint32_t status;
+
+ /* Generate stop bit */
+ mmio_write_32((uintptr_t)&base->control,
+ mmio_read_32((uintptr_t)&base->control) |
+ I2C_CONTROL_STOP);
+ marvell_i2c_interrupt_clear();
+
+ timeout = 0;
+ /* Read control register, check the control stop bit */
+ while ((mmio_read_32((uintptr_t)&base->control) & I2C_CONTROL_STOP) &&
+ (timeout++ < I2C_TIMEOUT_VALUE))
+ ;
+ if (timeout >= I2C_TIMEOUT_VALUE) {
+ ERROR("Stop bit didn't went down\n");
+ return -ETIMEDOUT;
+ }
+
+ /* check that stop bit went down */
+ if ((mmio_read_32((uintptr_t)&base->control) & I2C_CONTROL_STOP) != 0) {
+ ERROR("Stop bit didn't went down\n");
+ return -EPERM;
+ }
+
+ /* check the status */
+ if (marvell_i2c_lost_arbitration(&status)) {
+ ERROR("%s - %d: Lost arbitration, got status %x\n",
+ __func__, __LINE__, status);
+ return -EAGAIN;
+ }
+ if (status != I2C_STATUS_IDLE) {
+ ERROR("Got status %x after enable stop bit.\n", status);
+ return -EPERM;
+ }
+
+ return 0;
+}
+
+static int marvell_i2c_address_set(uint8_t chain, int command)
+{
+ uint32_t reg, status;
+
+ reg = (chain << I2C_DATA_ADDR_7BIT_OFFS) & I2C_DATA_ADDR_7BIT_MASK;
+ reg |= command;
+ mmio_write_32((uintptr_t)&base->data, reg);
+ udelay(1);
+
+ marvell_i2c_interrupt_clear();
+
+ if (marvell_i2c_wait_interrupt()) {
+ ERROR("Start clear bit timeout\n");
+ return -ETIMEDOUT;
+ }
+
+ /* check the status */
+ if (marvell_i2c_lost_arbitration(&status)) {
+ ERROR("%s - %d: Lost arbitration, got status %x\n",
+ __func__, __LINE__, status);
+ return -EAGAIN;
+ }
+ if (((status != I2C_STATUS_ADDR_R_ACK) && (command == I2C_CMD_READ)) ||
+ ((status != I2C_STATUS_ADDR_W_ACK) && (command == I2C_CMD_WRITE))) {
+ /* only in debug, since in boot we try to read the SPD
+ * of both DRAM, and we don't want error messages in cas
+ * DIMM doesn't exist.
+ */
+ INFO("%s: ERROR - status %x addr in %s mode.\n", __func__,
+ status, (command == I2C_CMD_WRITE) ? "Write" : "Read");
+ return -EPERM;
+ }
+
+ return 0;
+}
+
+/*
+ * The I2C module contains a clock divider to generate the SCL clock.
+ * This function calculates and sets the <N> and <M> fields in the I2C Baud
+ * Rate Register (t=01) to obtain given 'requested_speed'.
+ * The requested_speed will be equal to:
+ * CONFIG_SYS_TCLK / (10 * (M + 1) * (2 << N))
+ * Where M is the value represented by bits[6:3] and N is the value represented
+ * by bits[2:0] of "I2C Baud Rate Register".
+ * Therefore max M which can be set is 16 (2^4) and max N is 8 (2^3). So the
+ * lowest possible baudrate is:
+ * CONFIG_SYS_TCLK/(10 * (16 +1) * (2 << 8), which equals to:
+ * CONFIG_SYS_TCLK/87040. Assuming that CONFIG_SYS_TCLK=250MHz, the lowest
+ * possible frequency is ~2,872KHz.
+ */
+static unsigned int marvell_i2c_bus_speed_set(unsigned int requested_speed)
+{
+ unsigned int n, m, freq, margin, min_margin = 0xffffffff;
+ unsigned int actual_n = 0, actual_m = 0;
+ int val;
+
+ /* Calculate N and M for the TWSI clock baud rate */
+ for (n = 0; n < 8; n++) {
+ for (m = 0; m < 16; m++) {
+ freq = CONFIG_SYS_TCLK / (10 * (m + 1) * (2 << n));
+ val = requested_speed - freq;
+ margin = (val > 0) ? val : -val;
+
+ if ((freq <= requested_speed) &&
+ (margin < min_margin)) {
+ min_margin = margin;
+ actual_n = n;
+ actual_m = m;
+ }
+ }
+ }
+ VERBOSE("%s: actual_n = %u, actual_m = %u\n",
+ __func__, actual_n, actual_m);
+ /* Set the baud rate */
+ mmio_write_32((uintptr_t)&base->u.baudrate, (actual_m << 3) | actual_n);
+
+ return 0;
+}
+
+#ifdef DEBUG_I2C
+static int marvell_i2c_probe(uint8_t chip)
+{
+ int ret = 0;
+
+ ret = marvell_i2c_start_bit_set();
+ if (ret != 0) {
+ marvell_i2c_stop_bit_set();
+ ERROR("%s - %d: %s", __func__, __LINE__,
+ "marvell_i2c_start_bit_set failed\n");
+ return -EPERM;
+ }
+
+ ret = marvell_i2c_address_set(chip, I2C_CMD_WRITE);
+ if (ret != 0) {
+ marvell_i2c_stop_bit_set();
+ ERROR("%s - %d: %s", __func__, __LINE__,
+ "marvell_i2c_address_set failed\n");
+ return -EPERM;
+ }
+
+ marvell_i2c_stop_bit_set();
+
+ VERBOSE("%s: successful I2C probe\n", __func__);
+
+ return ret;
+}
+#endif
+
+/* regular i2c transaction */
+static int marvell_i2c_data_receive(uint8_t *p_block, uint32_t block_size)
+{
+ uint32_t reg, status, block_size_read = block_size;
+
+ /* Wait for cause interrupt */
+ if (marvell_i2c_wait_interrupt()) {
+ ERROR("Start clear bit timeout\n");
+ return -ETIMEDOUT;
+ }
+ while (block_size_read) {
+ if (block_size_read == 1) {
+ reg = mmio_read_32((uintptr_t)&base->control);
+ reg &= ~(I2C_CONTROL_ACK);
+ mmio_write_32((uintptr_t)&base->control, reg);
+ }
+ marvell_i2c_interrupt_clear();
+
+ if (marvell_i2c_wait_interrupt()) {
+ ERROR("Start clear bit timeout\n");
+ return -ETIMEDOUT;
+ }
+ /* check the status */
+ if (marvell_i2c_lost_arbitration(&status)) {
+ ERROR("%s - %d: Lost arbitration, got status %x\n",
+ __func__, __LINE__, status);
+ return -EAGAIN;
+ }
+ if ((status != I2C_STATUS_DATA_R_ACK) &&
+ (block_size_read != 1)) {
+ ERROR("Status %x in read transaction\n", status);
+ return -EPERM;
+ }
+ if ((status != I2C_STATUS_DATA_R_NAK) &&
+ (block_size_read == 1)) {
+ ERROR("Status %x in Rd Terminate\n", status);
+ return -EPERM;
+ }
+
+ /* read the data */
+ *p_block = (uint8_t) mmio_read_32((uintptr_t)&base->data);
+ VERBOSE("%s: place %d read %x\n", __func__,
+ block_size - block_size_read, *p_block);
+ p_block++;
+ block_size_read--;
+ }
+
+ return 0;
+}
+
+static int marvell_i2c_data_transmit(uint8_t *p_block, uint32_t block_size)
+{
+ uint32_t status, block_size_write = block_size;
+
+ if (marvell_i2c_wait_interrupt()) {
+ ERROR("Start clear bit timeout\n");
+ return -ETIMEDOUT;
+ }
+
+ while (block_size_write) {
+ /* write the data */
+ mmio_write_32((uintptr_t)&base->data, (uint32_t) *p_block);
+ VERBOSE("%s: index = %d, data = %x\n", __func__,
+ block_size - block_size_write, *p_block);
+ p_block++;
+ block_size_write--;
+
+ marvell_i2c_interrupt_clear();
+
+ if (marvell_i2c_wait_interrupt()) {
+ ERROR("Start clear bit timeout\n");
+ return -ETIMEDOUT;
+ }
+
+ /* check the status */
+ if (marvell_i2c_lost_arbitration(&status)) {
+ ERROR("%s - %d: Lost arbitration, got status %x\n",
+ __func__, __LINE__, status);
+ return -EAGAIN;
+ }
+ if (status != I2C_STATUS_DATA_W_ACK) {
+ ERROR("Status %x in write transaction\n", status);
+ return -EPERM;
+ }
+ }
+
+ return 0;
+}
+
+static int marvell_i2c_target_offset_set(uint8_t chip, uint32_t addr, int alen)
+{
+ uint8_t off_block[2];
+ uint32_t off_size;
+
+ if (alen == 2) { /* 2-byte addresses support */
+ off_block[0] = (addr >> 8) & 0xff;
+ off_block[1] = addr & 0xff;
+ off_size = 2;
+ } else { /* 1-byte addresses support */
+ off_block[0] = addr & 0xff;
+ off_size = 1;
+ }
+ VERBOSE("%s: off_size = %x addr1 = %x addr2 = %x\n", __func__,
+ off_size, off_block[0], off_block[1]);
+ return marvell_i2c_data_transmit(off_block, off_size);
+}
+
+static int marvell_i2c_unstuck(int ret)
+{
+ uint32_t v;
+
+ if (ret != -ETIMEDOUT)
+ return ret;
+ VERBOSE("Trying to \"unstuck i2c\"... ");
+ i2c_init(base);
+ mmio_write_32((uintptr_t)&base->unstuck, I2C_UNSTUCK_TRIGGER);
+ do {
+ v = mmio_read_32((uintptr_t)&base->unstuck);
+ } while (v & I2C_UNSTUCK_ONGOING);
+
+ if (v & I2C_UNSTUCK_ERROR) {
+ VERBOSE("failed - soft reset i2c\n");
+ ret = -EPERM;
+ } else {
+ VERBOSE("ok\n");
+ i2c_init(base);
+ ret = -EAGAIN;
+ }
+ return ret;
+}
+
+/*
+ * API Functions
+ */
+void i2c_init(void *i2c_base)
+{
+ /* For I2C speed and slave address, now we do not set them since
+ * we just provide the working speed and slave address in plat_def.h
+ * for i2c_init
+ */
+ base = (struct marvell_i2c_regs *)i2c_base;
+
+ /* Reset the I2C logic */
+ mmio_write_32((uintptr_t)&base->soft_reset, 0);
+
+ udelay(200);
+
+ marvell_i2c_bus_speed_set(CONFIG_SYS_I2C_SPEED);
+
+ /* Enable the I2C and slave */
+ mmio_write_32((uintptr_t)&base->control,
+ I2C_CONTROL_TWSIEN | I2C_CONTROL_ACK);
+
+ /* set the I2C slave address */
+ mmio_write_32((uintptr_t)&base->xtnd_slave_addr, 0);
+ mmio_write_32((uintptr_t)&base->slave_address, CONFIG_SYS_I2C_SLAVE);
+
+ /* unmask I2C interrupt */
+ mmio_write_32((uintptr_t)&base->control,
+ mmio_read_32((uintptr_t)&base->control) |
+ I2C_CONTROL_INTEN);
+
+ udelay(10);
+}
+
+/*
+ * i2c_read: - Read multiple bytes from an i2c device
+ *
+ * The higher level routines take into account that this function is only
+ * called with len < page length of the device (see configuration file)
+ *
+ * @chip: address of the chip which is to be read
+ * @addr: i2c data address within the chip
+ * @alen: length of the i2c data address (1..2 bytes)
+ * @buffer: where to write the data
+ * @len: how much byte do we want to read
+ * @return: 0 in case of success
+ */
+int i2c_read(uint8_t chip, uint32_t addr, int alen, uint8_t *buffer, int len)
+{
+ int ret = 0;
+ uint32_t counter = 0;
+
+#ifdef DEBUG_I2C
+ marvell_i2c_probe(chip);
+#endif
+
+ do {
+ if (ret != -EAGAIN && ret) {
+ ERROR("i2c transaction failed, after %d retries\n",
+ counter);
+ marvell_i2c_stop_bit_set();
+ return ret;
+ }
+
+ /* wait for 1 us for the interrupt clear to take effect */
+ if (counter > 0)
+ udelay(1);
+ counter++;
+
+ ret = marvell_i2c_start_bit_set();
+ if (ret) {
+ ret = marvell_i2c_unstuck(ret);
+ continue;
+ }
+
+ /* if EEPROM device */
+ if (alen != 0) {
+ ret = marvell_i2c_address_set(chip, I2C_CMD_WRITE);
+ if (ret)
+ continue;
+
+ ret = marvell_i2c_target_offset_set(chip, addr, alen);
+ if (ret)
+ continue;
+ ret = marvell_i2c_start_bit_set();
+ if (ret)
+ continue;
+ }
+
+ ret = marvell_i2c_address_set(chip, I2C_CMD_READ);
+ if (ret)
+ continue;
+
+ ret = marvell_i2c_data_receive(buffer, len);
+ if (ret)
+ continue;
+
+ ret = marvell_i2c_stop_bit_set();
+ } while ((ret == -EAGAIN) && (counter < I2C_MAX_RETRY_CNT));
+
+ if (counter == I2C_MAX_RETRY_CNT) {
+ ERROR("I2C transactions failed, got EAGAIN %d times\n",
+ I2C_MAX_RETRY_CNT);
+ ret = -EPERM;
+ }
+ mmio_write_32((uintptr_t)&base->control,
+ mmio_read_32((uintptr_t)&base->control) |
+ I2C_CONTROL_ACK);
+
+ udelay(1);
+ return ret;
+}
+
+/*
+ * i2c_write: - Write multiple bytes to an i2c device
+ *
+ * The higher level routines take into account that this function is only
+ * called with len < page length of the device (see configuration file)
+ *
+ * @chip: address of the chip which is to be written
+ * @addr: i2c data address within the chip
+ * @alen: length of the i2c data address (1..2 bytes)
+ * @buffer: where to find the data to be written
+ * @len: how much byte do we want to read
+ * @return: 0 in case of success
+ */
+int i2c_write(uint8_t chip, uint32_t addr, int alen, uint8_t *buffer, int len)
+{
+ int ret = 0;
+ uint32_t counter = 0;
+
+ do {
+ if (ret != -EAGAIN && ret) {
+ ERROR("i2c transaction failed\n");
+ marvell_i2c_stop_bit_set();
+ return ret;
+ }
+ /* wait for 1 us for the interrupt clear to take effect */
+ if (counter > 0)
+ udelay(1);
+ counter++;
+
+ ret = marvell_i2c_start_bit_set();
+ if (ret) {
+ ret = marvell_i2c_unstuck(ret);
+ continue;
+ }
+
+ ret = marvell_i2c_address_set(chip, I2C_CMD_WRITE);
+ if (ret)
+ continue;
+
+ /* if EEPROM device */
+ if (alen != 0) {
+ ret = marvell_i2c_target_offset_set(chip, addr, alen);
+ if (ret)
+ continue;
+ }
+
+ ret = marvell_i2c_data_transmit(buffer, len);
+ if (ret)
+ continue;
+
+ ret = marvell_i2c_stop_bit_set();
+ } while ((ret == -EAGAIN) && (counter < I2C_MAX_RETRY_CNT));
+
+ if (counter == I2C_MAX_RETRY_CNT) {
+ ERROR("I2C transactions failed, got EAGAIN %d times\n",
+ I2C_MAX_RETRY_CNT);
+ ret = -EPERM;
+ }
+
+ udelay(1);
+ return ret;
+}
projects / project / bcm63xx / atf.git / commitdiff