diff options
Diffstat (limited to 'boot/bootloader.c')
| -rw-r--r-- | boot/bootloader.c | 376 |
1 files changed, 0 insertions, 376 deletions
diff --git a/boot/bootloader.c b/boot/bootloader.c deleted file mode 100644 index 042414b..0000000 --- a/boot/bootloader.c +++ /dev/null @@ -1,376 +0,0 @@ -#include <hardware.h> -#include <zeta.h> -#include <fifo.h> - -#include <assert.h> -#include <stddef.h> -#include <string.h> - -#ifdef __GNUC__ -#define PACKED __attribute__((packed)) -#else -#define PACKED -#endif - -u16 -crc16(const void *buf, size_t len); - -enum header_type { - CMD_PING, - CMD_INFO, - CMD_BOOT, - CMD_READ, - CMD_WRITE, - CMD_IO_READ, - CMD_IO_WRITE, - CMD_ECHO -}; - -struct header { - u8 type; - u8 bank; - u16 address; - u16 length; - u16 checksum; -} PACKED; - -// static_assert(sizeof(struct header) == 8, "struct header is not PACKED"); - -enum error { - ERR_TIMEOUT = -1 -}; - -#define MAX_PACKET_SIZE 256 -#define TIMEOUT_MS 500 -#define MAX_ATTEMPTS 3 -#define MAX_TRANS_ATTEMPTS 5 - -u16 -crc16(const void *buf, size_t len); - -volatile struct fifo rx_fifo = {0, 0, {0}}; - -enum ack { - ACK = 0x00, - NACK = 0xFF -}; - -void -rx_isr(void) __critical __interrupt(0) -{ - fifo_push(&rx_fifo, sio_a_data); -} - -static volatile uint32_t millis = 0; - -void -ctc1_isr(void) __critical __interrupt(1) -{ - millis += 5; -} - -uint32_t -clock(void) -{ - volatile uint32_t ret; - DI; - ret = millis; - EI; - return ret; -} - -void -putbyte(unsigned char b) -{ - unsigned char ctrl = 0; - - sio_a_data = b; - - while (!(ctrl & 0x04)) { - sio_a_ctrl = 0; - ctrl = sio_a_ctrl; - } -} - -static volatile int32_t errno = 0; - -u8 -getbyte(void) -{ - u8 b; - uint32_t ms = clock(); - errno = 0; - while (fifo_empty(&rx_fifo)) { - if (clock() - ms > TIMEOUT_MS) { - errno = ERR_TIMEOUT; - return 0; - } - } - DI; - b = fifo_pop(&rx_fifo); - EI; - return b; -} - -void -flush(void) -{ - DI; - fifo_clear(&rx_fifo); - EI; -} - - -// Hamming(7,4) encoding -u8 -encode(u8 x) -{ - u8 y = 0; - const u8 c[4] = {0x61, 0x52, 0x34, 0x78}; - - for (u8 i = 0; i < 4; ++i) - y ^= ((x >> i) & 1) ? c[i] : 0; - - return y; -} - -// Hamming(7,4) decoding -u8 -decode(u8 x) -{ - u8 p = 0; - const u8 r[7] = {6, 5, 3, 7, 1, 2, 4}; - - for (int i = 0; i < 7; ++i) - p ^= ((x >> i) & 1) ? r[i] : 0; - - // Assume simple error, attempt correction - if (p) { - size_t i = 0; - - for (i = 0; i < LENGTH(r); ++i) { - if (r[i] == x) - break; - } - - x ^= (1 << i); - } - - return x & 0x0F; -} - - -int -read(void *buf, size_t count) -{ - u8 b; - u8 *p = buf; - - for (int n = 0; n < count; ++n) { - b = decode(getbyte()); - if (errno) - return errno; - - b |= (decode(getbyte()) << 4); - if (errno) - return errno; - - p[n] = b; - } - - return 0; -} - -int -write(const void *buf, size_t count) -{ - const u8 *p = buf; - - for (size_t i = 0; i < count; ++i) { - putbyte(encode(p[i] & 0x0F)); - putbyte(encode((p[i] >> 4) & 0x0F)); - } - - return 0; -} - -int -read_header(struct header *header) -{ - int err; - u8 ack; - u16 checksum; - - while (1) { - if ((err = read(header, sizeof(*header)))) - return err; - - checksum = header->checksum; - header->checksum = 0; - - if (checksum == crc16(header, sizeof(*header))) { - header->checksum = checksum; - ack = ACK; - write(&ack, sizeof(ack)); - return 0; - } else { - ack = NACK; - write(&ack, sizeof(ack)); - } - } -} - -int -read_buf(size_t len, void *buf) -{ - int err; - u8 ack; - u16 checksum; - - for (int i = 0; i < MAX_TRANS_ATTEMPTS; ++i) { - // TODO: reduce code? - if ((err = read(&checksum, sizeof(checksum))) - || (err = read(buf, len))) - break; - - if (checksum == crc16(buf, len)) { - ack = ACK; - write(&ack, sizeof(ack)); - return 0; - } else { - ack = NACK; - write(&ack, sizeof(ack)); - } - } - - return -1; -} - -int -write_buf(size_t len, const void *buf) -{ - int err; - u8 ack = NACK; - u16 checksum = crc16(buf, len); - - for (int i = 0; i < MAX_TRANS_ATTEMPTS; ++i){ - write(&checksum, sizeof(checksum)); - write(buf, len); - - // If TIMEOUT sending just give up - if ((err = read(&ack, sizeof(ack)))) - return err; - - if (ack == ACK) - return 0; - } - - return -1; -} - -// TODO: Restart after timeouts -void -loop(void) -{ - struct header header; - u8 buf[MAX_PACKET_SIZE]; - - while (1) { - if (read_header(&header)) { - flush(); - continue; - } - - switch (header.type) { - case CMD_BOOT: - ((void (*)(void))header.address)(); - break; - - case CMD_READ: - write_buf(header.length, (const void *)header.address); - break; - - case CMD_WRITE: - if (!read_buf(header.length, buf)) - memcpy((void *)header.address, buf, header.length); - break; - - case CMD_ECHO: - if (!read_buf(header.length, buf)) - write_buf(header.length, buf); - break; - - default: - break; - } - - flush(); - } -} - -static inline void -init_ctc(void) -{ - ctc_channel_0 = CTC_CTRL(0); - - /* 200Hz clock */ - ctc_channel_1 = CTC_CTRL(CTC_INT_BIT | CTC_PRESCALER_BIT - | CTC_TIME_CONST_BIT | CTC_RST_BIT); - ctc_channel_1 = 0; - - ctc_channel_2 = CTC_CTRL(0); - ctc_channel_3 = CTC_CTRL(0); - - // Interrupt table for CTC - // Final address is (Ireg << 8) | ctc_isr_ptr | {00/01/10/11} | 0 - ctc_channel_0 = CTC_INT_VEC(0x10); -} - -static inline void -init_pio(void) -{ - // Disable PIO interrupts - port_a_ctrl = PIO_INT_CTRL(0); - port_b_ctrl = PIO_INT_CTRL(0); -} - -static inline void -init_sio(void) -{ - static const u8 sio_a_cfg[] = { - 0b00011000, // Reset channel - 4 , // wr4 - 0b01000100, // X16 clock (115200), one stop bit, no parity - 1 , // wr1 - SIO_RX_INT_MD0 | SIO_RX_INT_MD1, // interrupt on every Rx, no wait function - 3 , // wr3 - 0b11000001, // enable Rx - 8 bit char - 5 , // wr5 - 0b01101000 // enable Tx - 8 bit char - }; - - static const u8 sio_b_cfg[] = { - 0b00011000, // Reset channel - 2 , // load interrupt vector - 0x1C // int_table_rx - }; - - for (u8 i = 0; i < LENGTH(sio_a_cfg); ++i) - sio_a_ctrl = sio_a_cfg[i]; - - for (u8 i = 0; i < LENGTH(sio_b_cfg); ++i) - sio_b_ctrl = sio_b_cfg[i]; -} - -void -main(void) -{ - init_ctc(); - init_pio(); - init_sio(); - - IM(2); - EI; - - loop(); -} |