// SPDX-License-Identifier: GPL-2.0+ /* * Chromium OS cros_ec driver - I2C interface * * Copyright (c) 2012 The Chromium OS Authors. */ /* * The Matrix Keyboard Protocol driver handles talking to the keyboard * controller chip. Mostly this is for keyboard functions, but some other * things have slipped in, so we provide generic services to talk to the * KBC. */ #include #include #include #include #ifdef DEBUG_TRACE #define debug_trace(fmt, b...) debug(fmt, #b) #else #define debug_trace(fmt, b...) #endif /** * Request format for protocol v3 * byte 0 0xda (EC_COMMAND_PROTOCOL_3) * byte 1-8 struct ec_host_request * byte 10- response data */ struct ec_host_request_i2c { /* Always 0xda to backward compatible with v2 struct */ uint8_t command_protocol; struct ec_host_request ec_request; } __packed; /* * Response format for protocol v3 * byte 0 result code * byte 1 packet_length * byte 2-9 struct ec_host_response * byte 10- response data */ struct ec_host_response_i2c { uint8_t result; uint8_t packet_length; struct ec_host_response ec_response; } __packed; static int cros_ec_i2c_packet(struct udevice *udev, int out_bytes, int in_bytes) { struct cros_ec_dev *dev = dev_get_uclass_priv(udev); struct dm_i2c_chip *chip = dev_get_parent_plat(udev); struct ec_host_request_i2c *ec_request_i2c = (struct ec_host_request_i2c *)dev->dout; struct ec_host_response_i2c *ec_response_i2c = (struct ec_host_response_i2c *)dev->din; struct i2c_msg i2c_msg[2]; int ret; i2c_msg[0].addr = chip->chip_addr; i2c_msg[0].flags = 0; i2c_msg[1].addr = chip->chip_addr; i2c_msg[1].flags = I2C_M_RD; /* one extra byte, to indicate v3 */ i2c_msg[0].len = out_bytes + 1; i2c_msg[0].buf = dev->dout; /* stitch on EC_COMMAND_PROTOCOL_3 */ memmove(&ec_request_i2c->ec_request, dev->dout, out_bytes); ec_request_i2c->command_protocol = EC_COMMAND_PROTOCOL_3; /* two extra bytes for v3 */ i2c_msg[1].len = in_bytes + 2; i2c_msg[1].buf = dev->din; ret = dm_i2c_xfer(udev, &i2c_msg[0], 2); if (ret) { printf("%s: Could not execute transfer: %d\n", __func__, ret); return ret; } /* When we send a v3 request to v2 ec, ec won't recognize the 0xda * (EC_COMMAND_PROTOCOL_3) and will return with status * EC_RES_INVALID_COMMAND with zero data length * * In case of invalid command for v3 protocol the data length * will be at least sizeof(struct ec_host_response) */ if (ec_response_i2c->result == EC_RES_INVALID_COMMAND && ec_response_i2c->packet_length == 0) return -EPROTONOSUPPORT; if (ec_response_i2c->packet_length < sizeof(struct ec_host_response)) { printf("%s: response of %u bytes too short; not a full hdr\n", __func__, ec_response_i2c->packet_length); return -EBADMSG; } /* drop result and packet_len */ memmove(dev->din, &ec_response_i2c->ec_response, in_bytes); return in_bytes; } static int cros_ec_i2c_command(struct udevice *udev, uint8_t cmd, int cmd_version, const uint8_t *dout, int dout_len, uint8_t **dinp, int din_len) { struct cros_ec_dev *dev = dev_get_uclass_priv(udev); struct dm_i2c_chip *chip = dev_get_parent_plat(udev); struct i2c_msg i2c_msg[2]; /* version8, cmd8, arglen8, out8[dout_len], csum8 */ int out_bytes = dout_len + 4; /* response8, arglen8, in8[din_len], checksum8 */ int in_bytes = din_len + 3; uint8_t *ptr; /* Receive input data, so that args will be dword aligned */ uint8_t *in_ptr; int len, csum, ret; /* * Sanity-check I/O sizes given transaction overhead in internal * buffers. */ if (out_bytes > sizeof(dev->dout)) { debug("%s: Cannot send %d bytes\n", __func__, dout_len); return -1; } if (in_bytes > sizeof(dev->din)) { debug("%s: Cannot receive %d bytes\n", __func__, din_len); return -1; } assert(dout_len >= 0); assert(dinp); i2c_msg[0].addr = chip->chip_addr; i2c_msg[0].len = out_bytes; i2c_msg[0].buf = dev->dout; i2c_msg[0].flags = 0; /* * Copy command and data into output buffer so we can do a single I2C * burst transaction. */ ptr = dev->dout; /* * in_ptr starts of pointing to a dword-aligned input data buffer. * We decrement it back by the number of header bytes we expect to * receive, so that the first parameter of the resulting input data * will be dword aligned. */ in_ptr = dev->din + sizeof(int64_t); if (dev->protocol_version != 2) { /* Something we don't support */ debug("%s: Protocol version %d unsupported\n", __func__, dev->protocol_version); return -1; } *ptr++ = EC_CMD_VERSION0 + cmd_version; *ptr++ = cmd; *ptr++ = dout_len; in_ptr -= 2; /* Expect status, length bytes */ memcpy(ptr, dout, dout_len); ptr += dout_len; *ptr++ = (uint8_t) cros_ec_calc_checksum(dev->dout, dout_len + 3); i2c_msg[1].addr = chip->chip_addr; i2c_msg[1].len = in_bytes; i2c_msg[1].buf = in_ptr; i2c_msg[1].flags = I2C_M_RD; /* Send output data */ cros_ec_dump_data("out", -1, dev->dout, out_bytes); ret = dm_i2c_xfer(udev, &i2c_msg[0], 2); if (ret) { debug("%s: Could not execute transfer to %s\n", __func__, udev->name); ret = -1; } if (*in_ptr != EC_RES_SUCCESS) { debug("%s: Received bad result code %d\n", __func__, *in_ptr); return -(int)*in_ptr; } len = in_ptr[1]; if (len + 3 > sizeof(dev->din)) { debug("%s: Received length %#02x too large\n", __func__, len); return -1; } csum = cros_ec_calc_checksum(in_ptr, 2 + len); if (csum != in_ptr[2 + len]) { debug("%s: Invalid checksum rx %#02x, calced %#02x\n", __func__, in_ptr[2 + din_len], csum); return -1; } din_len = min(din_len, len); cros_ec_dump_data("in", -1, in_ptr, din_len + 3); /* Return pointer to dword-aligned input data, if any */ *dinp = dev->din + sizeof(int64_t); return din_len; } static int cros_ec_probe(struct udevice *dev) { return cros_ec_register(dev); } static struct dm_cros_ec_ops cros_ec_ops = { .command = cros_ec_i2c_command, .packet = cros_ec_i2c_packet, }; static const struct udevice_id cros_ec_ids[] = { { .compatible = "google,cros-ec-i2c" }, { } }; U_BOOT_DRIVER(google_cros_ec_i2c) = { .name = "google_cros_ec_i2c", .id = UCLASS_CROS_EC, .of_match = cros_ec_ids, .probe = cros_ec_probe, .ops = &cros_ec_ops, };