126 lines
1.9 KiB
C
126 lines
1.9 KiB
C
#include "general.h"
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#include "platform.h"
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#include "swdptap.h"
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static void swdptap_turnaround(uint8_t dir)
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{
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static uint8_t olddir = 0;
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DEBUG("%s", dir ? "\n-> ":"\n<- ");
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/* Don't turnaround if direction not changing */
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if(dir == olddir) return;
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olddir = dir;
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if(dir)
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SWDIO_MODE_FLOAT();
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gpio_set(SWCLK_PORT, SWCLK_PIN);
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gpio_clear(SWCLK_PORT, SWCLK_PIN);
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if(!dir)
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SWDIO_MODE_DRIVE();
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}
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static uint8_t swdptap_bit_in(void)
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{
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uint16_t ret;
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ret = gpio_get(SWDIO_PORT, SWDIO_PIN);
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gpio_set(SWCLK_PORT, SWCLK_PIN);
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gpio_clear(SWCLK_PORT, SWCLK_PIN);
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DEBUG("%d", ret?1:0);
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return ret != 0;
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}
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static void swdptap_bit_out(uint8_t val)
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{
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DEBUG("%d", val);
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gpio_set_val(SWDIO_PORT, SWDIO_PIN, val);
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gpio_set(SWCLK_PORT, SWCLK_PIN);
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gpio_clear(SWCLK_PORT, SWCLK_PIN);
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}
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int
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swdptap_init(void)
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{
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swdptap_reset();
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swdptap_seq_out(0xE79E, 16); /* 0b0111100111100111 */
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swdptap_reset();
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swdptap_seq_out(0, 16);
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return 0;
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}
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void
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swdptap_reset(void)
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{
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swdptap_turnaround(0);
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/* 50 clocks with TMS high */
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for(int i = 0; i < 50; i++) swdptap_bit_out(1);
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}
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uint32_t
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swdptap_seq_in(int ticks)
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{
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uint32_t index = 1;
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uint32_t ret = 0;
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swdptap_turnaround(1);
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while(ticks--) {
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if(swdptap_bit_in()) ret |= index;
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index <<= 1;
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}
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return ret;
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}
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uint8_t
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swdptap_seq_in_parity(uint32_t *ret, int ticks)
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{
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uint32_t index = 1;
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uint8_t parity = 0;
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*ret = 0;
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swdptap_turnaround(1);
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while(ticks--) {
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if(swdptap_bit_in()) {
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*ret |= index;
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parity ^= 1;
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}
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index <<= 1;
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}
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if(swdptap_bit_in()) parity ^= 1;
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return parity;
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}
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void
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swdptap_seq_out(uint32_t MS, int ticks)
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{
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swdptap_turnaround(0);
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while(ticks--) {
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swdptap_bit_out(MS & 1);
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MS >>= 1;
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}
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}
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void
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swdptap_seq_out_parity(uint32_t MS, int ticks)
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{
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uint8_t parity = 0;
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swdptap_turnaround(0);
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while(ticks--) {
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swdptap_bit_out(MS & 1);
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parity ^= MS;
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MS >>= 1;
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}
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swdptap_bit_out(parity & 1);
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}
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