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fw: Minimal CDC implementation of new framing protocol

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Throwing away mode and length from incoming data. Adding mode and
length to outgoing data.

Splitting responses into frames small enough for the USB<->UART
transceiver to handle.
This commit is contained in:
Mikael Ågren 2024-09-16 14:26:12 +02:00
parent f9feb2e74d
commit 2f4298930c
No known key found for this signature in database
GPG Key ID: E02DA3D397792C46
3 changed files with 59 additions and 13 deletions
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9
hw/application_fpga/fw/tk1/main.c
View File

@ -412,12 +412,16 @@ int main(void)
/*@+mustfreeonly@*/
ctx.use_uss = FALSE;
uint8_t mode = 0;
uint8_t mode_bytes_left = 0;
scramble_ram();
for (;;) {
switch (state) {
case FW_STATE_INITIAL:
if (readcommand(&hdr, cmd, state) == -1) {
if (readcommand(&hdr, cmd, state, &mode,
&mode_bytes_left) == -1) {
state = FW_STATE_FAIL;
break;
}
@ -426,7 +430,8 @@ int main(void)
break;
case FW_STATE_LOADING:
if (readcommand(&hdr, cmd, state) == -1) {
if (readcommand(&hdr, cmd, state, &mode,
&mode_bytes_left) == -1) {
state = FW_STATE_FAIL;
break;
}

53
hw/application_fpga/fw/tk1/proto.c
View File

@ -22,7 +22,8 @@ static uint8_t genhdr(uint8_t id, uint8_t endpoint, uint8_t status,
enum cmdlen len);
static int parseframe(uint8_t b, struct frame_header *hdr);
static void write(uint8_t *buf, size_t nbytes);
static int read(uint8_t *buf, size_t bufsize, size_t nbytes);
static int read(uint8_t *buf, size_t bufsize, size_t nbytes, uint8_t *mode,
uint8_t *mode_bytes_left);
static int bytelen(enum cmdlen cmdlen);
static uint8_t genhdr(uint8_t id, uint8_t endpoint, uint8_t status,
@ -31,12 +32,13 @@ static uint8_t genhdr(uint8_t id, uint8_t endpoint, uint8_t status,
return (id << 5) | (endpoint << 3) | (status << 2) | len;
}
int readcommand(struct frame_header *hdr, uint8_t *cmd, int state)
int readcommand(struct frame_header *hdr, uint8_t *cmd, int state,
uint8_t *mode, uint8_t *mode_bytes_left)
{
uint8_t in = 0;
set_led((state == FW_STATE_LOADING) ? LED_BLACK : LED_WHITE);
in = readbyte();
in = readbyte(mode, mode_bytes_left);
if (parseframe(in, hdr) == -1) {
htif_puts("Couldn't parse header\n");
@ -45,7 +47,7 @@ int readcommand(struct frame_header *hdr, uint8_t *cmd, int state)
(void)memset(cmd, 0, CMDLEN_MAXBYTES);
// Now we know the size of the cmd frame, read it all
if (read(cmd, CMDLEN_MAXBYTES, hdr->len) != 0) {
if (read(cmd, CMDLEN_MAXBYTES, hdr->len, mode, mode_bytes_left) != 0) {
htif_puts("read: buffer overrun\n");
return -1;
}
@ -115,6 +117,10 @@ void fwreply(struct frame_header hdr, enum fwcmd rspcode, uint8_t *buf)
nbytes = bytelen(len);
// Mode Protocol Header
writebyte(MODE_CDC);
writebyte(2);
// Frame Protocol Header
writebyte(genhdr(hdr.id, hdr.endpoint, 0x0, len));
@ -122,7 +128,19 @@ void fwreply(struct frame_header hdr, enum fwcmd rspcode, uint8_t *buf)
writebyte(rspcode);
nbytes--;
write(buf, nbytes);
while (nbytes > 0) {
// Limit transfers to 64 bytes (2 byte header + 62 byte data) to
// fit in a single USB frame.
size_t tx_count = nbytes > 62 ? 62 : nbytes;
// Mode Protocol Header
writebyte(MODE_CDC);
writebyte(tx_count & 0xff);
// Data
write(buf, tx_count);
nbytes -= tx_count;
buf += tx_count;
}
}
void writebyte(uint8_t b)
@ -142,23 +160,40 @@ static void write(uint8_t *buf, size_t nbytes)
}
}
uint8_t readbyte(void)
uint8_t readbyte_(void)
{
for (;;) {
if (*can_rx) {
return *rx;
uint32_t b = *rx;
return b;
}
}
}
static int read(uint8_t *buf, size_t bufsize, size_t nbytes)
uint8_t readbyte(uint8_t *mode, uint8_t *mode_bytes_left)
{
if (*mode_bytes_left == 0) {
*mode = readbyte_();
if (*mode != MODE_CDC) {
htif_puts("We only support MODE_CDC\n");
} else {
*mode_bytes_left = readbyte_();
}
}
uint8_t b = readbyte_();
*mode_bytes_left -= 1;
return b;
}
static int read(uint8_t *buf, size_t bufsize, size_t nbytes, uint8_t *mode,
uint8_t *mode_bytes_left)
{
if (nbytes > bufsize) {
return -1;
}
for (int n = 0; n < nbytes; n++) {
buf[n] = readbyte();
buf[n] = readbyte(mode, mode_bytes_left);
}
return 0;

10
hw/application_fpga/fw/tk1/proto.h
View File

@ -8,6 +8,11 @@
#ifndef PROTO_H
#define PROTO_H
enum mode {
MODE_CDC = 0x40,
MODE_HID = 0x80,
};
enum endpoints {
DST_HW_IFPGA,
DST_HW_AFPGA,
@ -52,7 +57,8 @@ struct frame_header {
/*@ -exportlocal @*/
void writebyte(uint8_t b);
uint8_t readbyte(void);
uint8_t readbyte(uint8_t *mode, uint8_t *mode_bytes_left);
void fwreply(struct frame_header hdr, enum fwcmd rspcode, uint8_t *buf);
int readcommand(struct frame_header *hdr, uint8_t *cmd, int state);
int readcommand(struct frame_header *hdr, uint8_t *cmd, int state,
uint8_t *mode, uint8_t *mode_bytes_left);
#endif