diff options
Diffstat (limited to 'src/soc/nvidia/tegra/i2c.c')
| -rw-r--r-- | src/soc/nvidia/tegra/i2c.c | 180 |
1 files changed, 180 insertions, 0 deletions
diff --git a/src/soc/nvidia/tegra/i2c.c b/src/soc/nvidia/tegra/i2c.c new file mode 100644 index 0000000000..ddb54a56c0 --- /dev/null +++ b/src/soc/nvidia/tegra/i2c.c @@ -0,0 +1,180 @@ +/* + * 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. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include <arch/io.h> +#include <console/console.h> +#include <device/i2c.h> +#include <stdlib.h> +#include <string.h> +#include <soc/addressmap.h> + +#include "i2c.h" + +static int tegra_i2c_send_recv(struct tegra_i2c_regs *regs, int read, + uint32_t *headers, int header_words, + uint8_t *data, int data_len) +{ + while (data_len) { + uint32_t status = read32(®s->fifo_status); + int tx_empty = + status & TEGRA_I2C_FIFO_STATUS_TX_FIFO_EMPTY_CNT_MASK; + tx_empty >>= TEGRA_I2C_FIFO_STATUS_TX_FIFO_EMPTY_CNT_SHIFT; + int rx_full = + status & TEGRA_I2C_FIFO_STATUS_RX_FIFO_FULL_CNT_MASK; + rx_full >>= TEGRA_I2C_FIFO_STATUS_RX_FIFO_FULL_CNT_SHIFT; + + while (header_words && tx_empty) { + write32(*headers++, ®s->tx_packet_fifo); + 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(word, ®s->tx_packet_fifo); + data_len -= todo; + data += sizeof(word); + tx_empty--; + } + } + } + + uint32_t transfer_status = + read32(®s->packet_transfer_status); + + if (transfer_status & TEGRA_I2C_PKT_STATUS_NOACK_ADDR_MASK) { + printk(BIOS_ERR, + "%s: The address was not acknowledged.\n", + __func__); + return -1; + } else if (transfer_status & + TEGRA_I2C_PKT_STATUS_NOACK_DATA_MASK) { + printk(BIOS_ERR, + "%s: The data was not acknowledged.\n", + __func__); + return -1; + } else if (transfer_status & + TEGRA_I2C_PKT_STATUS_ARB_LOST_MASK) { + printk(BIOS_ERR, + "%s: Lost arbitration.\n", + __func__); + return -1; + } + } + + return 0; +} + +static int tegra_i2c_request(int bus, unsigned chip, int cont, int restart, + int read, void *data, int data_len) +{ + struct tegra_i2c_regs * const regs = tegra_i2c_bases[bus]; + 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_WORD0_PROTHDRSZ_SHIFT) | + (1 << IOHEADER_WORD0_PKTID_SHIFT) | + (bus << IOHEADER_WORD0_CONTROLLER_ID_SHIFT) | + IOHEADER_WORD0_PROTOCOL_I2C | + IOHEADER_WORD0_PKTTYPE_REQUEST; + + headers[1] = (data_len - 1) << IOHEADER_WORD1_PAYLOADSIZE_SHIFT; + + uint32_t slave_addr = (chip << 1) | (read ? 1 : 0); + headers[2] = IOHEADER_I2C_REQ_ADDRESS_MODE_7BIT | + (slave_addr << IOHEADER_I2C_REQ_SLAVE_ADDR_SHIFT); + if (read) + headers[2] |= IOHEADER_I2C_REQ_READ_WRITE_READ; + else + headers[2] |= IOHEADER_I2C_REQ_READ_WRITE_WRITE; + if (restart) + headers[2] |= IOHEADER_I2C_REQ_REPEAT_START_STOP_START; + if (cont) + headers[2] |= IOHEADER_I2C_REQ_CONTINUE_XFER_MASK; + + return tegra_i2c_send_recv(regs, read, headers, ARRAY_SIZE(headers), + data, data_len); +} + +static int i2c_readwrite(unsigned bus, unsigned chip, unsigned addr, + unsigned alen, uint8_t *buf, unsigned len, int read) +{ + const uint32_t max_payload = + (IOHEADER_WORD1_PAYLOADSIZE_MASK + 1) >> + IOHEADER_WORD1_PAYLOADSIZE_SHIFT; + uint8_t abuf[sizeof(addr)]; + + int i; + for (i = 0; i < alen; i++) + abuf[i] = addr >> ((alen - i - 1) * 8); + + if (tegra_i2c_request(bus, chip, !read, 0, 0, abuf, alen)) + return -1; + + while (len) { + int todo = MIN(len, max_payload); + int cont = (todo < len); + if (tegra_i2c_request(bus, chip, cont, 0, read, buf, todo)) { + // We should reset the controller here. + return -1; + } + len -= todo; + buf += todo; + } + return 0; +} + +int i2c_read(unsigned bus, unsigned chip, unsigned addr, + unsigned alen, uint8_t *buf, unsigned len) +{ + return i2c_readwrite(bus, chip, addr, alen, buf, len, 1); +} + +int i2c_write(unsigned bus, unsigned chip, unsigned addr, + unsigned alen, const uint8_t *buf, unsigned len) +{ + return i2c_readwrite(bus, chip, addr, alen, (void *)buf, len, 0); +} + +void i2c_init(unsigned bus) +{ + struct tegra_i2c_regs * const regs = tegra_i2c_bases[bus]; + + write32(TEGRA_I2C_CNFG_PACKET_MODE_EN_MASK, ®s->cnfg); +} |