u-boot/drivers/misc/cros_ec_spi.c
Simon Glass 2001b9a641 cros_ec: Fix two bugs in the SPI implementation
An incorrect message version is passed to the EC in some cases and the
parameters of one function are switched.

Fix these problems.

Signed-off-by: Simon Glass <sjg@chromium.org>
Tested-by: Ajay Kumar <ajaykumar.rs@samsung.com>
Reviewed-by: Jagannadha Sutradharudu Teki <jaganna@xilinx.com>
2014-08-06 00:18:01 +05:30

175 lines
4.3 KiB
C

/*
* 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 <spi.h>
int cros_ec_spi_packet(struct cros_ec_dev *dev, int out_bytes, int in_bytes)
{
int rv;
/* Do the transfer */
if (spi_claim_bus(dev->spi)) {
debug("%s: Cannot claim SPI bus\n", __func__);
return -1;
}
rv = spi_xfer(dev->spi, max(out_bytes, in_bytes) * 8,
dev->dout, dev->din,
SPI_XFER_BEGIN | SPI_XFER_END);
spi_release_bus(dev->spi);
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 cros_ec_dev *dev, uint8_t cmd, int cmd_version,
const uint8_t *dout, int dout_len,
uint8_t **dinp, int din_len)
{
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(dev->spi)) {
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(dev->spi, max(len, in_bytes) * 8, out, p,
SPI_XFER_BEGIN | SPI_XFER_END);
spi_release_bus(dev->spi);
if (rv) {
debug("%s: Cannot complete SPI transfer\n", __func__);
return -1;
}
len = min(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;
}
int cros_ec_spi_decode_fdt(struct cros_ec_dev *dev, const void *blob)
{
/* Decode interface-specific FDT params */
dev->max_frequency = fdtdec_get_int(blob, dev->node,
"spi-max-frequency", 500000);
dev->cs = fdtdec_get_int(blob, dev->node, "reg", 0);
return 0;
}
/**
* Initialize SPI protocol.
*
* @param dev CROS_EC device
* @param blob Device tree blob
* @return 0 if ok, -1 on error
*/
int cros_ec_spi_init(struct cros_ec_dev *dev, const void *blob)
{
dev->spi = spi_setup_slave_fdt(blob, dev->node, dev->parent_node);
if (!dev->spi) {
debug("%s: Could not setup SPI slave\n", __func__);
return -1;
}
return 0;
}