/*
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* Chromium OS cros_ec driver - I2C interface
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*
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* Copyright (c) 2012 The Chromium OS Authors.
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*
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* SPDX-License-Identifier: GPL-2.0+
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*/
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/*
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* The Matrix Keyboard Protocol driver handles talking to the keyboard
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* controller chip. Mostly this is for keyboard functions, but some other
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* things have slipped in, so we provide generic services to talk to the
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* KBC.
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*/
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#include <common.h>
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#include <dm.h>
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#include <i2c.h>
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#include <cros_ec.h>
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#ifdef DEBUG_TRACE
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#define debug_trace(fmt, b...) debug(fmt, #b)
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#else
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#define debug_trace(fmt, b...)
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#endif
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/**
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* Request format for protocol v3
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* byte 0 0xda (EC_COMMAND_PROTOCOL_3)
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* byte 1-8 struct ec_host_request
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* byte 10- response data
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*/
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struct ec_host_request_i2c {
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/* Always 0xda to backward compatible with v2 struct */
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uint8_t command_protocol;
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struct ec_host_request ec_request;
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} __packed;
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/*
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* Response format for protocol v3
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* byte 0 result code
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* byte 1 packet_length
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* byte 2-9 struct ec_host_response
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* byte 10- response data
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*/
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struct ec_host_response_i2c {
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uint8_t result;
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uint8_t packet_length;
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struct ec_host_response ec_response;
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} __packed;
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static int cros_ec_i2c_packet(struct udevice *udev, int out_bytes, int in_bytes)
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{
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struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
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struct dm_i2c_chip *chip = dev_get_parent_platdata(udev);
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struct ec_host_request_i2c *ec_request_i2c =
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(struct ec_host_request_i2c *)dev->dout;
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struct ec_host_response_i2c *ec_response_i2c =
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(struct ec_host_response_i2c *)dev->din;
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struct i2c_msg i2c_msg[2];
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int ret;
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i2c_msg[0].addr = chip->chip_addr;
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i2c_msg[0].flags = 0;
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i2c_msg[1].addr = chip->chip_addr;
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i2c_msg[1].flags = I2C_M_RD;
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/* one extra byte, to indicate v3 */
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i2c_msg[0].len = out_bytes + 1;
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i2c_msg[0].buf = dev->dout;
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/* stitch on EC_COMMAND_PROTOCOL_3 */
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memmove(&ec_request_i2c->ec_request, dev->dout, out_bytes);
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ec_request_i2c->command_protocol = EC_COMMAND_PROTOCOL_3;
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/* two extra bytes for v3 */
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i2c_msg[1].len = in_bytes + 2;
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i2c_msg[1].buf = dev->din;
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ret = dm_i2c_xfer(udev, &i2c_msg[0], 2);
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if (ret) {
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printf("%s: Could not execute transfer: %d\n", __func__, ret);
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return ret;
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}
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/* When we send a v3 request to v2 ec, ec won't recognize the 0xda
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* (EC_COMMAND_PROTOCOL_3) and will return with status
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* EC_RES_INVALID_COMMAND with zero data length
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*
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* In case of invalid command for v3 protocol the data length
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* will be at least sizeof(struct ec_host_response)
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*/
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if (ec_response_i2c->result == EC_RES_INVALID_COMMAND &&
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ec_response_i2c->packet_length == 0)
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return -EPROTONOSUPPORT;
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if (ec_response_i2c->packet_length < sizeof(struct ec_host_response)) {
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printf("%s: response of %u bytes too short; not a full hdr\n",
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__func__, ec_response_i2c->packet_length);
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return -EBADMSG;
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}
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/* drop result and packet_len */
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memmove(dev->din, &ec_response_i2c->ec_response, in_bytes);
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return in_bytes;
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}
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static int cros_ec_i2c_command(struct udevice *udev, uint8_t cmd,
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int cmd_version, const uint8_t *dout,
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int dout_len, uint8_t **dinp, int din_len)
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{
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struct cros_ec_dev *dev = dev_get_uclass_priv(udev);
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struct dm_i2c_chip *chip = dev_get_parent_platdata(udev);
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struct i2c_msg i2c_msg[2];
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/* version8, cmd8, arglen8, out8[dout_len], csum8 */
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int out_bytes = dout_len + 4;
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/* response8, arglen8, in8[din_len], checksum8 */
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int in_bytes = din_len + 3;
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uint8_t *ptr;
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/* Receive input data, so that args will be dword aligned */
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uint8_t *in_ptr;
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int len, csum, ret;
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/*
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* Sanity-check I/O sizes given transaction overhead in internal
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* buffers.
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*/
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if (out_bytes > sizeof(dev->dout)) {
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debug("%s: Cannot send %d bytes\n", __func__, dout_len);
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return -1;
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}
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if (in_bytes > sizeof(dev->din)) {
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debug("%s: Cannot receive %d bytes\n", __func__, din_len);
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return -1;
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}
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assert(dout_len >= 0);
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assert(dinp);
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i2c_msg[0].addr = chip->chip_addr;
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i2c_msg[0].len = out_bytes;
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i2c_msg[0].buf = dev->dout;
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i2c_msg[0].flags = 0;
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/*
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* Copy command and data into output buffer so we can do a single I2C
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* burst transaction.
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*/
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ptr = dev->dout;
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/*
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* in_ptr starts of pointing to a dword-aligned input data buffer.
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* We decrement it back by the number of header bytes we expect to
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* receive, so that the first parameter of the resulting input data
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* will be dword aligned.
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*/
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in_ptr = dev->din + sizeof(int64_t);
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if (dev->protocol_version != 2) {
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/* Something we don't support */
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debug("%s: Protocol version %d unsupported\n",
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__func__, dev->protocol_version);
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return -1;
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}
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*ptr++ = EC_CMD_VERSION0 + cmd_version;
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*ptr++ = cmd;
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*ptr++ = dout_len;
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in_ptr -= 2; /* Expect status, length bytes */
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memcpy(ptr, dout, dout_len);
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ptr += dout_len;
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*ptr++ = (uint8_t)
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cros_ec_calc_checksum(dev->dout, dout_len + 3);
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i2c_msg[1].addr = chip->chip_addr;
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i2c_msg[1].len = in_bytes;
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i2c_msg[1].buf = in_ptr;
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i2c_msg[1].flags = I2C_M_RD;
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/* Send output data */
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cros_ec_dump_data("out", -1, dev->dout, out_bytes);
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ret = dm_i2c_xfer(udev, &i2c_msg[0], 2);
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if (ret) {
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debug("%s: Could not execute transfer to %s\n", __func__,
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udev->name);
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ret = -1;
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}
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if (*in_ptr != EC_RES_SUCCESS) {
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debug("%s: Received bad result code %d\n", __func__, *in_ptr);
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return -(int)*in_ptr;
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}
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len = in_ptr[1];
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if (len + 3 > sizeof(dev->din)) {
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debug("%s: Received length %#02x too large\n",
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__func__, len);
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return -1;
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}
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csum = cros_ec_calc_checksum(in_ptr, 2 + len);
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if (csum != in_ptr[2 + len]) {
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debug("%s: Invalid checksum rx %#02x, calced %#02x\n",
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__func__, in_ptr[2 + din_len], csum);
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return -1;
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}
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din_len = min(din_len, len);
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cros_ec_dump_data("in", -1, in_ptr, din_len + 3);
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/* Return pointer to dword-aligned input data, if any */
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*dinp = dev->din + sizeof(int64_t);
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return din_len;
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}
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static int cros_ec_probe(struct udevice *dev)
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{
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return cros_ec_register(dev);
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}
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static struct dm_cros_ec_ops cros_ec_ops = {
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.command = cros_ec_i2c_command,
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.packet = cros_ec_i2c_packet,
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};
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static const struct udevice_id cros_ec_ids[] = {
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{ .compatible = "google,cros-ec-i2c" },
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{ }
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};
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U_BOOT_DRIVER(cros_ec_i2c) = {
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.name = "cros_ec_i2c",
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.id = UCLASS_CROS_EC,
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.of_match = cros_ec_ids,
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.probe = cros_ec_probe,
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.ops = &cros_ec_ops,
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};
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