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/*
* Chromium OS cros_ec driver - SPI interface
*
* Copyright (c) 2012 The Chromium OS Authors.
*
* SPDX-License-Identifier: GPL-2.0+
*/
/*
* 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 <common.h>
#include <cros_ec.h>
#include <dm.h>
#include <errno.h>
#include <spi.h>
DECLARE_GLOBAL_DATA_PTR;
int cros_ec_spi_packet(struct udevice *udev, int out_bytes, int in_bytes)
{
struct cros_ec_dev *dev = udev->uclass_priv;
struct spi_slave *slave = dev_get_parentdata(dev->dev);
int rv;
/* Do the transfer */
if (spi_claim_bus(slave)) {
debug("%s: Cannot claim SPI bus\n", __func__);
return -1;
}
rv = spi_xfer(slave, max(out_bytes, in_bytes) * 8,
dev->dout, dev->din,
SPI_XFER_BEGIN | SPI_XFER_END);
spi_release_bus(slave);
if (rv) {
debug("%s: Cannot complete SPI transfer\n", __func__);
return -1;
}
return in_bytes;
}
/**
* Send a command to a LPC CROS_EC device and return the reply.
*
* The device's internal input/output buffers are used.
*
* @param dev CROS_EC device
* @param cmd Command to send (EC_CMD_...)
* @param cmd_version Version of command to send (EC_VER_...)
* @param dout Output data (may be NULL If dout_len=0)
* @param dout_len Size of output data in bytes
* @param dinp Returns pointer to response data. This will be
* untouched unless we return a value > 0.
* @param din_len Maximum size of response in bytes
* @return number of bytes in response, or -1 on error
*/
int cros_ec_spi_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 = udev->uclass_priv;
struct spi_slave *slave = dev_get_parentdata(dev->dev);
int in_bytes = din_len + 4; /* status, length, checksum, trailer */
uint8_t *out;
uint8_t *p;
int csum, len;
int rv;
if (dev->protocol_version != 2) {
debug("%s: Unsupported EC protcol version %d\n",
__func__, dev->protocol_version);
return -1;
}
/*
* Sanity-check input size to make sure it plus transaction overhead
* fits in the internal device buffer.
*/
if (in_bytes > sizeof(dev->din)) {
debug("%s: Cannot receive %d bytes\n", __func__, din_len);
return -1;
}
/* We represent message length as a byte */
if (dout_len > 0xff) {
debug("%s: Cannot send %d bytes\n", __func__, dout_len);
return -1;
}
/*
* Clear input buffer so we don't get false hits for MSG_HEADER
*/
memset(dev->din, '\0', in_bytes);
if (spi_claim_bus(slave)) {
debug("%s: Cannot claim SPI bus\n", __func__);
return -1;
}
out = dev->dout;
out[0] = EC_CMD_VERSION0 + cmd_version;
out[1] = cmd;
out[2] = (uint8_t)dout_len;
memcpy(out + 3, dout, dout_len);
csum = cros_ec_calc_checksum(out, 3)
+ cros_ec_calc_checksum(dout, dout_len);
out[3 + dout_len] = (uint8_t)csum;
/*
* Send output data and receive input data starting such that the
* message body will be dword aligned.
*/
p = dev->din + sizeof(int64_t) - 2;
len = dout_len + 4;
cros_ec_dump_data("out", cmd, out, len);
rv = spi_xfer(slave, max(len, in_bytes) * 8, out, p,
SPI_XFER_BEGIN | SPI_XFER_END);
spi_release_bus(slave);
if (rv) {
debug("%s: Cannot complete SPI transfer\n", __func__);
return -1;
}
len = min((int)p[1], din_len);
cros_ec_dump_data("in", -1, p, len + 3);
/* Response code is first byte of message */
if (p[0] != EC_RES_SUCCESS) {
printf("%s: Returned status %d\n", __func__, p[0]);
return -(int)(p[0]);
}
/* Check checksum */
csum = cros_ec_calc_checksum(p, len + 2);
if (csum != p[len + 2]) {
debug("%s: Invalid checksum rx %#02x, calced %#02x\n", __func__,
p[2 + len], csum);
return -1;
}
/* Anything else is the response data */
*dinp = p + 2;
return len;
}
static int cros_ec_probe(struct udevice *dev)
{
return cros_ec_register(dev);
}
static struct dm_cros_ec_ops cros_ec_ops = {
.packet = cros_ec_spi_packet,
.command = cros_ec_spi_command,
};
static const struct udevice_id cros_ec_ids[] = {
{ .compatible = "google,cros-ec" },
{ }
};
U_BOOT_DRIVER(cros_ec_spi) = {
.name = "cros_ec",
.id = UCLASS_CROS_EC,
.of_match = cros_ec_ids,
.probe = cros_ec_probe,
.ops = &cros_ec_ops,
};
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