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/* Copyright (c) 2014 The Chromium OS Authors. All rights reserved.
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*
* Megachips DisplayPort to HDMI protocol converter / level shifter driver.
*/
#include "config.h"
#include "console.h"
#include "common.h"
#include "mcdp28x0.h"
#include "timer.h"
#include "usart-stm32f0.h"
#include "util.h"
#define CPRINTF(format, args...) cprintf(CC_USBPD, format, ## args)
#undef MCDP_DEBUG
#ifdef MCDP_DEBUG
static inline void print_buffer(uint8_t *buf, int cnt)
{
int i;
CPRINTF("buf:");
for (i = 0; i < cnt; i++) {
if (i && !(i % 4))
CPRINTF("\n ");
CPRINTF("[%02d]0x%02x ", i, buf[i]);
}
CPRINTF("\n");
}
#else
static inline void print_buffer(uint8_t *buf, int cnt) {}
#endif
USART_CONFIG(usart_mcdp, CONFIG_MCDP28X0, 115200, MCDP_INBUF_MAX,
MCDP_OUTBUF_MAX, NULL, NULL);
/**
* Compute checksum.
*
* @msg message bytes to compute checksum on.
* @cnt count of message bytes.
* @return partial checksum.
*/
static uint8_t compute_checksum(const uint8_t *msg, int cnt)
{
int i;
/* 1st byte (not in msg) is always cnt + 2, so seed chksum with that */
uint8_t chksum = cnt + 2;
for (i = 0; i < cnt; i++)
chksum += msg[i];
return ~chksum + 1;
}
/**
* transmit message over serial
*
* Packet consists of:
* msg[0] == length including this byte + cnt + chksum
* msg[1] == 1st message byte
* msg[cnt+1] == last message byte
* msg[cnt+2] == checksum
*
* @msg message bytes
* @cnt count of message bytes
* @return zero if success, error code otherwise
*/
static int tx_serial(const uint8_t *msg, int cnt)
{
uint8_t out = cnt + 2;
uint8_t chksum = compute_checksum(msg, cnt);
if (out_stream_write(&usart_mcdp.out, &out, 1) != 1)
return EC_ERROR_UNKNOWN;
if (out_stream_write(&usart_mcdp.out, msg, cnt) != cnt)
return EC_ERROR_UNKNOWN;
if (out_stream_write(&usart_mcdp.out, &chksum, 1) != 1)
return EC_ERROR_UNKNOWN;
print_buffer(usart_mcdp_tx_buffer, cnt + 2);
return EC_SUCCESS;
}
/**
* receive message over serial
*
* @msg pointer to buffer to read message into
* @cnt count of message bytes
* @return zero if success, error code otherwise
*/
static int rx_serial(uint8_t *msg, int cnt)
{
size_t read;
int retry = 2;
read = in_stream_read(&usart_mcdp.in, msg, cnt);
while ((read < cnt) && retry) {
usleep(100*MSEC);
read += in_stream_read(&usart_mcdp.in, msg + read,
cnt - read);
retry--;
}
print_buffer(msg, cnt);
return !(read == cnt);
}
void mcdp_enable(void)
{
usart_init(&usart_mcdp);
}
void mcdp_disable(void)
{
usart_shutdown(&usart_mcdp);
}
int mcdp_get_info(struct mcdp_info *info)
{
uint8_t inbuf[MCDP_RSP_LEN(MCDP_LEN_GETINFO)];
const uint8_t msg[2] = {MCDP_CMD_GETINFO, 0x00}; /* cmd + msg type */
if (tx_serial(msg, sizeof(msg)))
return EC_ERROR_UNKNOWN;
if (rx_serial(inbuf, sizeof(inbuf)))
return EC_ERROR_UNKNOWN;
/* check length & returned command ... no checksum provided */
if (((inbuf[0] - 1) != sizeof(inbuf)) ||
(inbuf[1] != MCDP_CMD_GETINFO))
return EC_ERROR_UNKNOWN;
memcpy(info, &inbuf[2], MCDP_LEN_GETINFO);
#ifdef MCDP_DEBUG
CPRINTF("family:%04x chipid:%04x irom:%d.%d.%d fw:%d.%d.%d\n",
MCDP_FAMILY(info->family), MCDP_CHIPID(info->chipid),
info->irom.major, info->irom.minor, info->irom.build,
info->fw.major, info->fw.minor, info->fw.build);
#endif
return EC_SUCCESS;
}
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