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common/swdptap: Slight speed increase and better setup time for write.

This commit is contained in:
Uwe Bonnes 2020-05-03 19:17:03 +02:00
parent 64f3dff8a8
commit 4698a26bab
1 changed files with 21 additions and 13 deletions
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34
src/platforms/common/swdptap.c
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@ -27,6 +27,14 @@ enum {
SWDIO_STATUS_FLOAT = 0,
SWDIO_STATUS_DRIVE
};
static void swdptap_turnaround(int dir) __attribute__ ((optimize(3)));
static uint32_t swdptap_seq_in(int ticks) __attribute__ ((optimize(3)));
static bool swdptap_seq_in_parity(uint32_t *ret, int ticks)
__attribute__ ((optimize(3)));
static void swdptap_seq_out(uint32_t MS, int ticks)
__attribute__ ((optimize(3)));
static void swdptap_seq_out_parity(uint32_t MS, int ticks)
__attribute__ ((optimize(3)));
static void swdptap_turnaround(int dir)
{
@ -76,33 +84,33 @@ static uint32_t swdptap_seq_in(int ticks)
static bool swdptap_seq_in_parity(uint32_t *ret, int ticks)
{
uint32_t index = 1;
uint8_t parity = 0;
uint32_t res = 0;
bool bit;
int len = ticks;
swdptap_turnaround(SWDIO_STATUS_FLOAT);
while (len--) {
gpio_clear(SWCLK_PORT, SWCLK_PIN);
bit = gpio_get(SWDIO_PORT, SWDIO_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
if (bit) {
res |= index;
parity ^= 1;
}
index <<= 1;
gpio_clear(SWCLK_PORT, SWCLK_PIN);
}
gpio_clear(SWCLK_PORT, SWCLK_PIN);
int parity = __builtin_popcount(res);
bit = gpio_get(SWDIO_PORT, SWDIO_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
if (bit)
parity ^= 1;
parity++;
gpio_clear(SWCLK_PORT, SWCLK_PIN);
#ifdef DEBUG_SWD_BITS
for (int i = 0; i < len; i++)
DEBUG("%d", (res & (1 << i)) ? 1 : 0);
#endif
*ret = res;
return parity;
return (parity & 1);
}
static void swdptap_seq_out(uint32_t MS, int ticks)
@ -115,30 +123,30 @@ static void swdptap_seq_out(uint32_t MS, int ticks)
swdptap_turnaround(SWDIO_STATUS_DRIVE);
while (ticks--) {
gpio_set_val(SWDIO_PORT, SWDIO_PIN, data);
gpio_clear(SWCLK_PORT, SWCLK_PIN);
MS >>= 1;
data = MS & 1;
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_clear(SWCLK_PORT, SWCLK_PIN);
}
gpio_clear(SWCLK_PORT, SWCLK_PIN);
}
static void swdptap_seq_out_parity(uint32_t MS, int ticks)
{
uint8_t parity = 0;
int parity = __builtin_popcount(MS);
int data = MS & 1;
#ifdef DEBUG_SWD_BITS
for (int i = 0; i < ticks; i++)
DEBUG("%d", (MS & (1 << i)) ? 1 : 0);
#endif
swdptap_turnaround(SWDIO_STATUS_DRIVE);
gpio_set_val(SWDIO_PORT, SWDIO_PIN, data);
MS >>= 1;
while (ticks--) {
gpio_set_val(SWDIO_PORT, SWDIO_PIN, data);
parity ^= MS;
MS >>= 1;
gpio_set(SWCLK_PORT, SWCLK_PIN);
data = MS & 1;
gpio_set(SWCLK_PORT, SWCLK_PIN);
gpio_set_val(SWDIO_PORT, SWDIO_PIN, data);
MS >>= 1;
gpio_clear(SWCLK_PORT, SWCLK_PIN);
}
gpio_set_val(SWDIO_PORT, SWDIO_PIN, parity & 1);