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libftdi/swdptap.c: Substantial speed increase for bitbanging SWD. 

Provide the swd sequences unrolled.
This commit is contained in:
Uwe Bonnes 2018-05-29 20:55:30 +02:00
parent 992ccf91a9
commit fce25b9fd5
1 changed files with 106 additions and 2 deletions
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108
src/platforms/libftdi/swdptap.c
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@ -18,8 +18,8 @@
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
/* MPSSE bit-banging SW-DP interface over FTDI.
* Slow, but usable.
/* MPSSE bit-banging SW-DP interface over FTDI with loop unrolled.
* Speed is sensible.
*/
#include <stdio.h>
@ -125,3 +125,107 @@ void swdptap_bit_out(bool val)
platform_buffer_write(cmd, 3);
}
bool swdptap_seq_in_parity(uint32_t *res, int ticks)
{
int index = ticks + 1;
uint8_t cmd[4];
unsigned int parity = 0;
cmd[0] = MPSSE_TMS_IN_PORT;
cmd[1] = MPSSE_TMS_SHIFT;
cmd[2] = 0;
cmd[3] = 0;
swdptap_turnaround(1);
while (index--) {
platform_buffer_write(cmd, 4);
}
uint8_t data[33];
unsigned int ret = 0;
platform_buffer_read(data, ticks + 1);
if (data[ticks] & 0x08)
parity ^= 1;
while (ticks--) {
if (data[ticks] & MPSSE_TMS_IN_PIN) {
parity ^= 1;
ret |= (1 << ticks);
}
}
*res = ret;
return parity;
}
uint32_t swdptap_seq_in(int ticks)
{
int index = ticks;
uint8_t cmd[4];
cmd[0] = MPSSE_TMS_IN_PORT;
cmd[1] = MPSSE_TMS_SHIFT;
cmd[2] = 0;
cmd[3] = 0;
swdptap_turnaround(1);
while (index--) {
platform_buffer_write(cmd, 4);
}
uint8_t data[32];
uint32_t ret = 0;
platform_buffer_read(data, ticks);
while (ticks--) {
if (data[ticks] & MPSSE_TMS_IN_PIN)
ret |= (1 << ticks);
}
return ret;
}
void swdptap_seq_out(uint32_t MS, int ticks)
{
uint8_t cmd[15];
uint index = 0;
swdptap_turnaround(0);
while (ticks) {
cmd[index++] = MPSSE_TMS_SHIFT;
if (ticks >= 7) {
cmd[index++] = 6;
cmd[index++] = MS & 0x7f;
MS >>= 7;
ticks -= 7;
} else {
cmd[index++] = ticks - 1;
cmd[index++] = MS & 0x7f;
ticks = 0;
}
}
platform_buffer_write(cmd, index);
}
void swdptap_seq_out_parity(uint32_t MS, int ticks)
{
uint8_t parity = 0;
int steps = ticks;
uint8_t cmd[18];
uint index = 0;
uint32_t data = MS;
swdptap_turnaround(0);
while (steps) {
cmd[index++] = MPSSE_TMS_SHIFT;
if (steps >= 7) {
cmd[index++] = 6;
cmd[index++] = data & 0x7f;
data >>= 7;
steps -= 7;
} else {
cmd[index++] = steps - 1;
cmd[index++] = data & 0x7f;
steps = 0;
}
}
while (ticks--) {
parity ^= MS;
MS >>= 1;
}
cmd[index++] = MPSSE_TMS_SHIFT;
cmd[index++] = 0;
cmd[index++] = parity;
platform_buffer_write(cmd, index);
}