471 lines
16 KiB
C
471 lines
16 KiB
C
/* firmware for STM8S-microcontroller-based HDMI firewall programmer
|
|
* Copyright (C) 2019-2021 King Kévin <kingkevin@cuvoodoo.info>
|
|
* SPDX-License-Identifier: GPL-3.0-or-later
|
|
*/
|
|
#include <stdint.h>
|
|
#include <stdbool.h>
|
|
#include <stdlib.h>
|
|
|
|
#include "stm8s.h"
|
|
#include "main.h"
|
|
#include "softi2c_master.h"
|
|
#include "eeprom_blockprog.h"
|
|
|
|
// blink RUN LED to show error
|
|
static bool led_error = false;
|
|
|
|
// set when the button is pressed
|
|
static volatile bool rw_button_pressed = false;
|
|
|
|
// AWU tick count
|
|
static volatile uint8_t awu_tick = 0;
|
|
|
|
// to store the current E-EDID (EDID + extension)
|
|
static uint8_t edid[256];
|
|
|
|
// function RAM (code in RAM)
|
|
uint8_t f_ram[112 + 5]; // use RAM_SEG size in main.map (plus some margin)
|
|
|
|
// function for saving EDID + extension to EEPROM, to put in RAM
|
|
bool (*ram_eeprom_blockprog)(const uint8_t* data, uint16_t length);
|
|
|
|
// size of RAM segment
|
|
volatile uint8_t RAM_SEG_LEN;
|
|
|
|
// get the size of the RAM segment
|
|
static inline void get_ram_section_length() {
|
|
__asm__("mov _RAM_SEG_LEN, #l_RAM_SEG");
|
|
}
|
|
|
|
// copy functions to RAM
|
|
static bool ram_cpy() {
|
|
get_ram_section_length();
|
|
if (RAM_SEG_LEN > ARRAY_LENGTH(f_ram)) {
|
|
return false;
|
|
}
|
|
for (uint8_t i = 0; i < RAM_SEG_LEN; i++) {
|
|
f_ram[i] = ((uint8_t *)eeprom_blockprog)[i];
|
|
}
|
|
ram_eeprom_blockprog = (bool (*)(const uint8_t* data, uint16_t length)) &f_ram;
|
|
return true;
|
|
}
|
|
|
|
// blocking wait (in 10 us steps, up to UINT32_MAX / 10)
|
|
static void wait_10us(uint32_t us10)
|
|
{
|
|
us10 = ((us10 / (1 << CLK->CKDIVR.fields.HSIDIV)) * 1000) / 206; // calibrated for 1 ms
|
|
while (us10--); // burn energy
|
|
}
|
|
|
|
void putc(char c)
|
|
{
|
|
while (!UART1->SR.fields.TXE); // wait until TX buffer is empty
|
|
UART1->DR.reg = c; // put character in buffer to be transmitted
|
|
// don't wait until the transmission is complete
|
|
}
|
|
|
|
void puts(const char* s)
|
|
{
|
|
if (NULL == s) {
|
|
return;
|
|
}
|
|
while (*s) {
|
|
putc(*s++);
|
|
IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
|
|
}
|
|
}
|
|
|
|
void putn(uint8_t n)
|
|
{
|
|
n &= 0x0f; // ensure it's a nibble
|
|
if (n < 0xa) {
|
|
putc('0' + n);
|
|
} else {
|
|
putc('a' + (n - 0x0a));
|
|
}
|
|
}
|
|
|
|
void puth(uint8_t h)
|
|
{
|
|
putn(h >> 4);
|
|
putn(h & 0x0f);
|
|
}
|
|
|
|
// verify (E-)EDID checksums
|
|
// the sum of the bytes (including checksum at the end) must be 0
|
|
static bool checksum_ok(const uint8_t* data, uint16_t length)
|
|
{
|
|
uint8_t checksum = 0;
|
|
for (uint16_t i = 0; i < length; i++) {
|
|
checksum += data[i];
|
|
}
|
|
return (0 == checksum);
|
|
}
|
|
|
|
// return if the current EDID is valid
|
|
/* from HDMI 1.3a specification
|
|
* All Sinks shall contain an CEA-861-D compliant E-EDID data structure.
|
|
* A Source shall read the EDID 1.3 and first CEA Extension to determine the capabilities supported
|
|
by the Sink.
|
|
* The first 128 bytes of the E-EDID shall contain an EDID 1.3 structure. The contents of this
|
|
structure shall also meet the requirements of CEA-861-D.
|
|
*
|
|
* HDMI 2.1 uses CTA-861-G
|
|
* this uses EDID 1.4 structure
|
|
* EDID 1.3/1.4 is 128 bytes long, and can point to 128 bytes extension
|
|
* EDID 2.0 with its 256 bytes does not seem to be used in HDMI at all
|
|
* DisplayID with its variable-length structure meant to replace E-EDID only seems to be used in DisplayPort
|
|
* I have no idea how more than 1 extension is supported since technically the ROM is limited to 256 bytes
|
|
*/
|
|
static uint16_t edid_length(void)
|
|
{
|
|
puts("EDID check: ");
|
|
// check EDID 1.3/1.4 fixed pattern header
|
|
if (0x00 != edid[0] || 0xff != edid[1] || 0xff != edid[2] || 0xff != edid[3] || 0xff != edid[4] || 0xff != edid[5] || 0xff != edid[6] || 0x00 != edid[7]) {
|
|
puts("invalid header\r\n");
|
|
return 0;
|
|
}
|
|
|
|
if (1 == edid[18]) { // EDID 1.3/1.4 128-byte structure
|
|
if (checksum_ok(&edid[0], 128)) {
|
|
if (0 == edid[126]) { // no extension
|
|
puts("128 bytes\r\n");
|
|
return 128;
|
|
} else { // extension available
|
|
// the usual extension is CEA EDID Timing Extension (with extension tag 02), but we allow others
|
|
// no idea how more than 1 extension is supported
|
|
if (checksum_ok(&edid[128], 128)) {
|
|
puts("256 bytes (with extension)\r\n");
|
|
return 256;
|
|
} else {
|
|
puts("extension CRC error\r\n");
|
|
return 0; // EDID is broken
|
|
}
|
|
}
|
|
} else {
|
|
puts("CRC error\r\n");
|
|
return 0;
|
|
}
|
|
} else if (2 == edid[18]) { // EDID 2.0 256-byte structure
|
|
if (checksum_ok(&edid[0], 256)) {
|
|
puts("256 bytes (no extension)\r\n");
|
|
return 256;
|
|
} else {
|
|
puts("CRC error\r\n");
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
// load EDID + extension from EEPROM
|
|
static void load_edid(void)
|
|
{
|
|
for (uint16_t i = 0; i < ARRAY_LENGTH(edid); i++) {
|
|
edid[i] = *(uint8_t*)(EEPROM_ADDR + i);
|
|
}
|
|
}
|
|
|
|
// save EDID + extension in EEPROM
|
|
static bool save_edid(void)
|
|
{
|
|
// modify EDID to include the character indicating the firewall
|
|
const char firewall_indicator = '|'; // sun character to indicate the firewall
|
|
// ensure descriptor 4 is for Display name
|
|
if ((0 == edid[108]) && (0 == edid[109]) && (0 == edid[110]) && (0xfc == edid[111]) && (0 == edid[112])) { // ensure descriptor 4 is for Display name
|
|
uint8_t last_c; // position of last character
|
|
for (last_c = 113; last_c < 126 && edid[last_c] != '\n'; last_c++); // find position for inserting our character
|
|
if (firewall_indicator != edid[last_c - 1]) { // the last character is not yet the sun
|
|
if (last_c > 125) { // ensure we insert as the last possible character
|
|
last_c = 125;
|
|
}
|
|
edid[last_c++] = firewall_indicator; // insert sun
|
|
if (last_c < 126) {
|
|
edid[last_c++] = '\n'; // insert LF to terminate string
|
|
}
|
|
while (last_c < 126) {
|
|
edid[last_c++] = ' '; // insert padding space
|
|
}
|
|
// calculate new checksum
|
|
uint8_t checksum = 0;
|
|
for (uint8_t i = 0; i < 127; i++) {
|
|
checksum += edid[i];
|
|
}
|
|
edid[127] = (256 - checksum);
|
|
}
|
|
}
|
|
|
|
return ram_eeprom_blockprog(edid, edid_length());
|
|
}
|
|
|
|
// size in byte of a page in the I²C EEPROM (for faster page write)
|
|
#define I2C_EEPROM_PAGE_SIZE 16U
|
|
|
|
// read EDID from I²C memory
|
|
// return if succeeded
|
|
static bool read_edid(void)
|
|
{
|
|
if (!softi2c_master_setup(10)) {
|
|
puts("I²C setup failed");
|
|
return false;
|
|
}
|
|
// read all pages
|
|
// in theory I could read the whole address space at once, but in practice short clock pulses appear after some bytes, corrupting the data flow. I have no idea what the cause of theses glitches is (I even used WFI to reduce EMI as recommended in the errata)
|
|
for (uint16_t i = 0; i < ARRAY_LENGTH(edid); i += I2C_EEPROM_PAGE_SIZE) {
|
|
const uint8_t address[] = {i}; // address of page to read
|
|
uint8_t data[I2C_EEPROM_PAGE_SIZE]; // data from page
|
|
bool same = false; // if the data read is the same
|
|
while (!same) { // read until the data is the same
|
|
const bool rc = softi2c_master_address_read(I2C_SLAVE, address, ARRAY_LENGTH(address), data, ARRAY_LENGTH(data)); // read I²C EEPROM data
|
|
if (!rc) {
|
|
puts("I²C read failed");
|
|
return false;
|
|
}
|
|
// check if the data is the same and copy it to EDID
|
|
same = true;
|
|
for (uint16_t j = 0; j < I2C_EEPROM_PAGE_SIZE; j++) {
|
|
if (data[j] != edid[i + j]) {
|
|
same = false;
|
|
}
|
|
edid[i + j] = data[j]; // save last read data
|
|
}
|
|
}
|
|
}
|
|
softi2c_master_release(); // release I²C again
|
|
|
|
return true;
|
|
}
|
|
|
|
// write EDID to I²C memory
|
|
// return if succeeded
|
|
static bool write_edid(void)
|
|
{
|
|
if (!softi2c_master_setup(10)) {
|
|
puts("I²C setup failed");
|
|
return false;
|
|
}
|
|
// write all page
|
|
const uint16_t length = edid_length();
|
|
for (uint16_t i = 0; i < length; i += I2C_EEPROM_PAGE_SIZE) {
|
|
const uint8_t address[] = {i};
|
|
const bool rc = softi2c_master_address_write(I2C_SLAVE, address, ARRAY_LENGTH(address), &edid[i], I2C_EEPROM_PAGE_SIZE); // write I²C EEPROM page
|
|
if (!rc) {
|
|
puts("I²C write failed");
|
|
return false;
|
|
}
|
|
wait_10us((5 + 1) * 100); // wait 5 ms for the page write to complete
|
|
}
|
|
softi2c_master_release(); // release I²C again
|
|
return true;
|
|
}
|
|
|
|
void main(void)
|
|
{
|
|
sim(); // disable interrupts (while we reconfigure them)
|
|
|
|
CLK->CKDIVR.fields.HSIDIV = CLK_CKDIVR_HSIDIV_DIV0; // don't divide internal 16 MHz clock
|
|
CLK->CKDIVR.fields.CPUDIV = CLK_CKDIVR_CPUDIV_DIV0; // don't divide CPU frequency to 16 MHz
|
|
while (!CLK->ICKR.fields.HSIRDY); // wait for internal oscillator to be ready
|
|
|
|
// save power by disabling unused peripheral
|
|
CLK_PCKENR1 = CLK_PCKENR1_I2C | CLK_PCKENR1_UART1234; // keep I²C and UART
|
|
CLK_PCKENR2 = CLK_PCKENR2_AWU; // keep AWU
|
|
|
|
// configure LEDs
|
|
EDID_LED_PORT->DDR.reg |= EDID_LED_PIN; // switch pin to output
|
|
EDID_LED_PORT->CR1.reg &= ~EDID_LED_PIN; // use in open-drain mode
|
|
edid_led_off(); // start with LED off
|
|
RUN_LED_PORT->DDR.reg |= RUN_LED_PIN; // switch pin to output
|
|
RUN_LED_PORT->CR1.reg &= ~RUN_LED_PIN; // use in open-drain mode
|
|
run_led_off(); // start with LED off
|
|
|
|
// configure read/write button
|
|
RW_BUTTON_PORT->DDR.reg &= ~RW_BUTTON_PIN; // switch pin to input
|
|
RW_BUTTON_PORT->CR1.reg |= RW_BUTTON_PIN; // pull up
|
|
RW_BUTTON_PORT->CR2.reg |= RW_BUTTON_PIN; // enable external interrupt
|
|
EXTI->CR1.fields.PDIS = EXTI_FALLING_EDGE; // interrupt only on falling edges (WARNING hard coded port)
|
|
|
|
// configure auto-wakeup (AWU) to be able to refresh the watchdog
|
|
// 128 kHz LSI used by default in option bytes CKAWUSEL
|
|
// we skip measuring the LS clock frequency since there is no need to be precise
|
|
AWU->TBR.fields.AWUTB = 10; // interval range: 128-256 ms
|
|
AWU->APR.fields.APR = 0x3e; // set time to 256 ms
|
|
AWU_CSR |= AWU_CSR_AWUEN; // enable AWU (start only when entering wait or active halt mode)
|
|
|
|
// configure UART for debug output
|
|
UART1->CR1.fields.M = 0; // 8 data bits
|
|
UART1->CR3.fields.STOP = 0; // 1 stop bit
|
|
UART1->BRR2.reg = 0x0B; // set baud rate to 115200 (at 16 MHz)
|
|
UART1->BRR1.reg = 0x08; // set baud rate to 115200 (at 16 MHz)
|
|
UART1->CR2.fields.TEN = 1; // enable TX
|
|
|
|
// load function in RAM
|
|
ram_cpy();
|
|
|
|
// configure independent watchdog (very loose, just it case the firmware hangs)
|
|
IWDG->KR.fields.KEY = IWDG_KR_KEY_REFRESH; // reset watchdog
|
|
IWDG->KR.fields.KEY = IWDG_KR_KEY_ENABLE; // start watchdog
|
|
IWDG->KR.fields.KEY = IWDG_KR_KEY_ACCESS; // allows changing the prescale
|
|
IWDG->PR.fields.PR = IWDG_PR_DIV256; // set prescale to longest time (1.02s)
|
|
IWDG->KR.fields.KEY = IWDG_KR_KEY_REFRESH; // reset watchdog
|
|
|
|
puts("\r\nCuVoodoo HDMI firewall programmer ready\r\n");
|
|
|
|
// erase saved EDID when button is pressed on boot
|
|
if (0 == (RW_BUTTON_PORT->IDR.reg & RW_BUTTON_PIN)) { // button is pressed while booting
|
|
for (uint16_t i = 0; i < ARRAY_LENGTH(edid); i++) {
|
|
edid[i] = 0; // create empty EDID
|
|
}
|
|
ram_eeprom_blockprog(edid, ARRAY_LENGTH(edid)); // erase EDID
|
|
puts("EEPROM EDID erased\r\n");
|
|
}
|
|
load_edid(); // load EDID from EEPROM
|
|
bool edid_valid = (0 != edid_length()); // verify if EDID is valid
|
|
if (edid_valid) {
|
|
puts("EEPROM EDID valid\r\n");
|
|
} else {
|
|
puts("EEPROM EDID not valid\r\n");
|
|
}
|
|
|
|
rim(); // re-enable interrupts
|
|
bool action = false; // if an action has been performed
|
|
while (true) {
|
|
IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
|
|
// handle button press
|
|
if (rw_button_pressed) {
|
|
wait_10us(10000); // wait 100 ms for the noise to be gone
|
|
IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
|
|
if (0 == (RW_BUTTON_PORT->IDR.reg & RW_BUTTON_PIN)) { // ensure the button is pressed (the pull-up is really weak)
|
|
run_led_off(); // clear RUN LED to see result at the end
|
|
uint8_t press_duration = 1; // start counting how long the button is pressed
|
|
while (0 == (RW_BUTTON_PORT->IDR.reg & RW_BUTTON_PIN)) { // wait until button is depressed
|
|
wait_10us(10000); // wait for 100 ms
|
|
press_duration++;
|
|
IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
|
|
if (press_duration >= 30) { // 3 seconds already passed
|
|
break; // stop waiting for button to be released
|
|
}
|
|
}
|
|
led_error = false; // reset error state
|
|
if (press_duration < 30) { // less than 3 sec
|
|
puts("read I²C EDID: ");
|
|
run_led_on(); // indicate we started
|
|
if (read_edid()) { // read EDID from I²C
|
|
puts(" OK\r\n");
|
|
edid_valid = (0 != edid_length()); // verify if EDID is valid
|
|
if (edid_valid) { // read EDID is valid
|
|
puts("I²C EDID valid\r\n");
|
|
IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
|
|
|
|
/*
|
|
puts("EDID data:\r\n");
|
|
for (uint16_t i = 0; i < ARRAY_LENGTH(edid); i++) {
|
|
puth(edid[i]);
|
|
putc(' ');
|
|
}
|
|
puts("\r\n");
|
|
*/
|
|
|
|
if (save_edid()) {; // save to EEPROM
|
|
puts("I²C EDID saved to EEPROM\r\n");
|
|
} else {
|
|
led_error = true; // indicate write error
|
|
puts("could not save EDID to EEPROM\r\n");
|
|
load_edid(); // re-load EDID from EEPROM
|
|
edid_valid = (0 != edid_length()); // verify if EDID is valid
|
|
}
|
|
IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
|
|
} else { // read EDID is not valid
|
|
puts("I²C EDID not valid, reloading from EEPROM\r\n");
|
|
led_error = true; // indicate read error
|
|
load_edid(); // re-load EDID from EEPROM
|
|
edid_valid = (0 != edid_length()); // verify if EDID is valid
|
|
}
|
|
} else { // read error
|
|
puts("\r\n"); // error should have been printed
|
|
led_error = true; // indicate read error
|
|
load_edid(); // re-load EDID from EEPROM
|
|
edid_valid = (0 != edid_length()); // verify if EDID is valid
|
|
}
|
|
} else { // button pressed > 3s
|
|
run_led_on(); // indicate we started
|
|
if (edid_valid) { // the current EDID we have is valid and is ready to be written
|
|
led_error = true; // error indication will be cleared if everything succeeded
|
|
puts("writing I²C EDID: ");
|
|
if (write_edid()) { // write EDID to I²C EEPROM succeeded
|
|
puts("OK\r\n");
|
|
const uint16_t target_length = edid_length(); // remember the length of the EDID we programmed
|
|
puts("reading back EDID: ");
|
|
if (read_edid()) { // read EDID back from I²C
|
|
puts("OK\r\n");
|
|
if (edid_length() == target_length) { // ensure the EDID length between what we programmed and read is the same
|
|
puts("verifying EDID: ");
|
|
bool identical_edid = true; // to find out if EDID is identical
|
|
for (uint16_t i = 0; i < target_length; i++) { // compare EDID
|
|
if (edid[i] != *(uint8_t*)(EEPROM_ADDR + i)) { // ensure the data is the same
|
|
identical_edid = false; // EDID is not identical
|
|
break; // stop comparing
|
|
}
|
|
}
|
|
if (identical_edid) { // EDID has been successfully programmed
|
|
puts("OK\r\n");
|
|
led_error = false; // no error happened
|
|
} else {
|
|
puts("failed (wrong data)\r\n");
|
|
}
|
|
} else {
|
|
puts("failed (not length)\r\n");
|
|
}
|
|
} else {
|
|
puts("\r\n"); // error should have been printed
|
|
}
|
|
puts("reloading EEPROM EDID\r\n");
|
|
load_edid(); // re-load EDID from EEPROM after it has been overwritten from the read
|
|
edid_valid = (0 != edid_length()); // verify if EDID is valid (should be as before
|
|
} else {
|
|
puts("\r\n"); // error should have been printed
|
|
}
|
|
} else {
|
|
puts("\r\n"); // error should have been printed
|
|
led_error = true; // we can't program an invalid EDID
|
|
}
|
|
}
|
|
}
|
|
action = true; // remember we performed an action
|
|
rw_button_pressed = false; // clear flag
|
|
}
|
|
// update LED
|
|
if ((awu_tick & 0x7) < 4) { // on period of blink (every second)
|
|
edid_led_on(); // on period
|
|
if (led_error) {
|
|
run_led_on(); // start blinking
|
|
}
|
|
} else {
|
|
if (!edid_valid) { // EDID not valid
|
|
edid_led_off(); // blink to let user know
|
|
}
|
|
if (led_error) {
|
|
run_led_off(); // blink to indicate error
|
|
}
|
|
}
|
|
if (action) { // something has been performed, check if other flags have been set meanwhile
|
|
action = false; // clear flag
|
|
} else { // nothing down
|
|
wfi(); // go to sleep (wait for any interrupt, also starting AWU)
|
|
}
|
|
}
|
|
}
|
|
|
|
void awu(void) __interrupt(IRQ_AWU) // auto wakeup
|
|
{
|
|
volatile uint8_t awuf = AWU_CSR; // clear interrupt flag by reading it (reading is required, and volatile prevents compiler optimization)
|
|
awu_tick++; // increment tick count
|
|
// let the main loop kick the dog
|
|
}
|
|
|
|
void rw_button_isr(void) __interrupt(IRQ_EXTI3) // button pressed
|
|
{
|
|
rw_button_pressed = true; // notify main loop
|
|
}
|