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/*
* This file is part of the coreboot project.
*
* Copyright 2013 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 <device/mmio.h>
#include <console/console.h>
#include <delay.h>
#include <device/i2c_simple.h>
#include <string.h>
#include <soc/addressmap.h>
#include <stdint.h>
#include "i2c.h"
static void do_bus_clear(int bus)
{
struct tegra_i2c_bus_info *info = &tegra_i2c_info[bus];
struct tegra_i2c_regs * const regs = info->base;
uint32_t bc;
int i, timeout_ms = 10;
// BUS CLEAR regs (from TRM):
// 1. Reset the I2C controller (already done)
// 2. Set the # of clock pulses required (using default of 9)
// 3. Select STOP condition (using default of 1 = STOP)
// 4. Set TERMINATE condition (1 = IMMEDIATE)
bc = read32(®s->bus_clear_config);
bc |= I2C_BUS_CLEAR_CONFIG_BC_TERMINATE_IMMEDIATE;
write32(®s->bus_clear_config, bc);
// 4.1 Set MSTR_CONFIG_LOAD and wait for clear
write32(®s->config_load, I2C_CONFIG_LOAD_MSTR_CONFIG_LOAD_ENABLE);
for (i = 0; i < timeout_ms * 10 && (read32(®s->config_load) &
I2C_CONFIG_LOAD_MSTR_CONFIG_LOAD_ENABLE); i++) {
printk(BIOS_DEBUG, "%s: wait for MSTR_CONFIG_LOAD to clear\n",
__func__);
udelay(100);
}
// 5. Set ENABLE to start the bus clear op
write32(®s->bus_clear_config, bc | I2C_BUS_CLEAR_CONFIG_BC_ENABLE);
for (i = 0; i < timeout_ms * 10 && (read32(®s->bus_clear_config) &
I2C_BUS_CLEAR_CONFIG_BC_ENABLE); i++) {
printk(BIOS_DEBUG, "%s: wait for bus clear completion\n",
__func__);
udelay(100);
}
}
static int tegra_i2c_send_recv(int bus, int read,
uint32_t *headers, int header_words,
uint8_t *data, int data_len)
{
struct tegra_i2c_bus_info *info = &tegra_i2c_info[bus];
struct tegra_i2c_regs * const regs = info->base;
while (data_len) {
uint32_t status = read32(®s->fifo_status);
int tx_empty = status & I2C_FIFO_STATUS_TX_FIFO_EMPTY_CNT_MASK;
tx_empty >>= I2C_FIFO_STATUS_TX_FIFO_EMPTY_CNT_SHIFT;
int rx_full = status & I2C_FIFO_STATUS_RX_FIFO_FULL_CNT_MASK;
rx_full >>= I2C_FIFO_STATUS_RX_FIFO_FULL_CNT_SHIFT;
while (header_words && tx_empty) {
write32(®s->tx_packet_fifo, *headers++);
header_words--;
tx_empty--;
}
if (!header_words) {
if (read) {
while (data_len && rx_full) {
uint32_t word = read32(®s->rx_fifo);
int todo = MIN(data_len, sizeof(word));
memcpy(data, &word, todo);
data_len -= todo;
data += sizeof(word);
rx_full--;
}
} else {
while (data_len && tx_empty) {
uint32_t word;
int todo = MIN(data_len, sizeof(word));
memcpy(&word, data, todo);
write32(®s->tx_packet_fifo, word);
data_len -= todo;
data += sizeof(word);
tx_empty--;
}
}
}
uint32_t transfer_status =
read32(®s->packet_transfer_status);
if (transfer_status & I2C_PKT_STATUS_NOACK_ADDR) {
printk(BIOS_ERR,
"%s: The address was not acknowledged.\n",
__func__);
info->reset_func(info->reset_bit);
i2c_init(bus);
return -1;
} else if (transfer_status & I2C_PKT_STATUS_NOACK_DATA) {
printk(BIOS_ERR,
"%s: The data was not acknowledged.\n",
__func__);
info->reset_func(info->reset_bit);
i2c_init(bus);
return -1;
} else if (transfer_status & I2C_PKT_STATUS_ARB_LOST) {
printk(BIOS_ERR,
"%s: Lost arbitration.\n",
__func__);
info->reset_func(info->reset_bit);
/* Use Tegra bus clear registers to unlock SDA */
do_bus_clear(bus);
/* re-init i2c controller */
i2c_init(bus);
/* Return w/error, let caller decide what to do */
return -1;
}
}
return 0;
}
static int tegra_i2c_request(int bus, unsigned int chip, int cont, int restart,
int read, void *data, int data_len)
{
uint32_t headers[3];
if (restart && cont) {
printk(BIOS_ERR, "%s: Repeat start and continue xfer are "
"mutually exclusive.\n", __func__);
return -1;
}
headers[0] = (0 << IOHEADER_PROTHDRSZ_SHIFT) |
(1 << IOHEADER_PKTID_SHIFT) |
(bus << IOHEADER_CONTROLLER_ID_SHIFT) |
IOHEADER_PROTOCOL_I2C | IOHEADER_PKTTYPE_REQUEST;
headers[1] = (data_len - 1) << IOHEADER_PAYLOADSIZE_SHIFT;
uint32_t slave_addr = (chip << 1) | (read ? 1 : 0);
headers[2] = IOHEADER_I2C_REQ_ADDR_MODE_7BIT |
(slave_addr << IOHEADER_I2C_REQ_SLAVE_ADDR_SHIFT);
if (read)
headers[2] |= IOHEADER_I2C_REQ_READ;
if (restart)
headers[2] |= IOHEADER_I2C_REQ_REPEAT_START;
if (cont)
headers[2] |= IOHEADER_I2C_REQ_CONTINUE_XFER;
return tegra_i2c_send_recv(bus, read, headers, ARRAY_SIZE(headers),
data, data_len);
}
static int i2c_transfer_segment(unsigned int bus, unsigned int chip, int restart,
int read, void *buf, int len)
{
const uint32_t max_payload =
(IOHEADER_PAYLOADSIZE_MASK + 1) >> IOHEADER_PAYLOADSIZE_SHIFT;
while (len) {
int todo = MIN(len, max_payload);
int cont = (todo < len);
if (tegra_i2c_request(bus, chip, cont, restart,
read, buf, todo))
return -1;
len -= todo;
buf += todo;
}
return 0;
}
int platform_i2c_transfer(unsigned int bus, struct i2c_msg *segments, int count)
{
struct i2c_msg *seg = segments;
int i;
if (bus >= g_num_i2c_buses) {
printk(BIOS_ERR, "%s: ERROR: invalid I2C bus (%u)\n", __func__,
bus);
return -1;
}
for (i = 0; i < count; seg++, i++) {
if (i2c_transfer_segment(bus, seg->slave, i < count - 1,
seg->flags & I2C_M_RD,
seg->buf, seg->len))
return -1;
}
return 0;
}
void i2c_init(unsigned int bus)
{
struct tegra_i2c_regs *regs;
if (bus >= g_num_i2c_buses) {
printk(BIOS_ERR, "%s: ERROR: invalid I2C bus (%u)\n", __func__,
bus);
return;
}
regs = tegra_i2c_info[bus].base;
write32(®s->cnfg, I2C_CNFG_PACKET_MODE_EN);
}
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