aboutsummaryrefslogtreecommitdiff
path: root/boot/devmode
diff options
context:
space:
mode:
Diffstat (limited to 'boot/devmode')
-rw-r--r--boot/devmode/Makefile12
-rw-r--r--boot/devmode/bootloader.c339
-rw-r--r--boot/devmode/crc16.c49
-rw-r--r--boot/devmode/devmode.h42
4 files changed, 442 insertions, 0 deletions
diff --git a/boot/devmode/Makefile b/boot/devmode/Makefile
new file mode 100644
index 0000000..24c841a
--- /dev/null
+++ b/boot/devmode/Makefile
@@ -0,0 +1,12 @@
+BUILD=$(PROJECT_ROOT)/build/boot/devmode
+
+TARGET=$(BUILD)/devmode.hex
+IHX=$(BUILD)/devmode.ihx
+
+ASM=$(wildcard *.asm)
+SRC=$(wildcard *.c)
+
+all : $(TARGET)
+
+include $(PROJECT_ROOT)/payload.mk
+include $(PROJECT_ROOT)/include.mk
diff --git a/boot/devmode/bootloader.c b/boot/devmode/bootloader.c
new file mode 100644
index 0000000..dfa9786
--- /dev/null
+++ b/boot/devmode/bootloader.c
@@ -0,0 +1,339 @@
+#include "devmode.h"
+
+#include <hardware.h>
+
+#include <fifo.h>
+
+#include <assert.h>
+#include <stddef.h>
+#include <string.h>
+
+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();
+}
diff --git a/boot/devmode/crc16.c b/boot/devmode/crc16.c
new file mode 100644
index 0000000..ac17529
--- /dev/null
+++ b/boot/devmode/crc16.c
@@ -0,0 +1,49 @@
+#include <zeta.h>
+#include <stddef.h>
+
+static const u16 crc_table[256] = {
+ 0x0000, 0x1021, 0x2042, 0x3063, 0x4084, 0x50A5, 0x60C6, 0x70E7,
+ 0x8108, 0x9129, 0xA14A, 0xB16B, 0xC18C, 0xD1AD, 0xE1CE, 0xF1EF,
+ 0x1231, 0x0210, 0x3273, 0x2252, 0x52B5, 0x4294, 0x72F7, 0x62D6,
+ 0x9339, 0x8318, 0xB37B, 0xA35A, 0xD3BD, 0xC39C, 0xF3FF, 0xE3DE,
+ 0x2462, 0x3443, 0x0420, 0x1401, 0x64E6, 0x74C7, 0x44A4, 0x5485,
+ 0xA56A, 0xB54B, 0x8528, 0x9509, 0xE5EE, 0xF5CF, 0xC5AC, 0xD58D,
+ 0x3653, 0x2672, 0x1611, 0x0630, 0x76D7, 0x66F6, 0x5695, 0x46B4,
+ 0xB75B, 0xA77A, 0x9719, 0x8738, 0xF7DF, 0xE7FE, 0xD79D, 0xC7BC,
+ 0x48C4, 0x58E5, 0x6886, 0x78A7, 0x0840, 0x1861, 0x2802, 0x3823,
+ 0xC9CC, 0xD9ED, 0xE98E, 0xF9AF, 0x8948, 0x9969, 0xA90A, 0xB92B,
+ 0x5AF5, 0x4AD4, 0x7AB7, 0x6A96, 0x1A71, 0x0A50, 0x3A33, 0x2A12,
+ 0xDBFD, 0xCBDC, 0xFBBF, 0xEB9E, 0x9B79, 0x8B58, 0xBB3B, 0xAB1A,
+ 0x6CA6, 0x7C87, 0x4CE4, 0x5CC5, 0x2C22, 0x3C03, 0x0C60, 0x1C41,
+ 0xEDAE, 0xFD8F, 0xCDEC, 0xDDCD, 0xAD2A, 0xBD0B, 0x8D68, 0x9D49,
+ 0x7E97, 0x6EB6, 0x5ED5, 0x4EF4, 0x3E13, 0x2E32, 0x1E51, 0x0E70,
+ 0xFF9F, 0xEFBE, 0xDFDD, 0xCFFC, 0xBF1B, 0xAF3A, 0x9F59, 0x8F78,
+ 0x9188, 0x81A9, 0xB1CA, 0xA1EB, 0xD10C, 0xC12D, 0xF14E, 0xE16F,
+ 0x1080, 0x00A1, 0x30C2, 0x20E3, 0x5004, 0x4025, 0x7046, 0x6067,
+ 0x83B9, 0x9398, 0xA3FB, 0xB3DA, 0xC33D, 0xD31C, 0xE37F, 0xF35E,
+ 0x02B1, 0x1290, 0x22F3, 0x32D2, 0x4235, 0x5214, 0x6277, 0x7256,
+ 0xB5EA, 0xA5CB, 0x95A8, 0x8589, 0xF56E, 0xE54F, 0xD52C, 0xC50D,
+ 0x34E2, 0x24C3, 0x14A0, 0x0481, 0x7466, 0x6447, 0x5424, 0x4405,
+ 0xA7DB, 0xB7FA, 0x8799, 0x97B8, 0xE75F, 0xF77E, 0xC71D, 0xD73C,
+ 0x26D3, 0x36F2, 0x0691, 0x16B0, 0x6657, 0x7676, 0x4615, 0x5634,
+ 0xD94C, 0xC96D, 0xF90E, 0xE92F, 0x99C8, 0x89E9, 0xB98A, 0xA9AB,
+ 0x5844, 0x4865, 0x7806, 0x6827, 0x18C0, 0x08E1, 0x3882, 0x28A3,
+ 0xCB7D, 0xDB5C, 0xEB3F, 0xFB1E, 0x8BF9, 0x9BD8, 0xABBB, 0xBB9A,
+ 0x4A75, 0x5A54, 0x6A37, 0x7A16, 0x0AF1, 0x1AD0, 0x2AB3, 0x3A92,
+ 0xFD2E, 0xED0F, 0xDD6C, 0xCD4D, 0xBDAA, 0xAD8B, 0x9DE8, 0x8DC9,
+ 0x7C26, 0x6C07, 0x5C64, 0x4C45, 0x3CA2, 0x2C83, 0x1CE0, 0x0CC1,
+ 0xEF1F, 0xFF3E, 0xCF5D, 0xDF7C, 0xAF9B, 0xBFBA, 0x8FD9, 0x9FF8,
+ 0x6E17, 0x7E36, 0x4E55, 0x5E74, 0x2E93, 0x3EB2, 0x0ED1, 0x1EF0
+};
+
+u16
+crc16(const void *buf, size_t len)
+{
+ const u8 *p = buf;
+
+ u16 crc = 0;
+ while (len--)
+ crc = crc_table[(crc >> 8) ^ (*p++)] ^ (crc << 8);
+
+ return crc;
+}
diff --git a/boot/devmode/devmode.h b/boot/devmode/devmode.h
new file mode 100644
index 0000000..f3322d0
--- /dev/null
+++ b/boot/devmode/devmode.h
@@ -0,0 +1,42 @@
+#ifndef DEVMODE_H
+#define DEVMODE_H
+
+#include <zeta.h>
+
+#ifdef __GNUC__
+#define PACKED __attribute__((packed))
+#else
+#define PACKED
+#endif
+
+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
+
+#endif // DEVMODE_H
generated by cgit v1.2.3 (git 2.50.1) at 2025-10-31 11:47:28 +0000