* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. *
***************************************************************************/
+/* 2014-12: Addition of the SWD protocol support is based on the initial work
+ * by Paul Fertser and modifications by Jean-Christian de Rivaz. */
+
#ifdef HAVE_CONFIG_H
#include "config.h"
#endif
#include <jtag/interface.h>
#include <jtag/commands.h>
+/* YUK! - but this is currently a global.... */
+extern struct jtag_interface *jtag_interface;
+
/**
* Function bitbang_stableclocks
* issues a number of clock cycles while staying in a stable state.
*/
static void bitbang_stableclocks(int num_cycles);
+static void bitbang_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay_clk);
+
struct bitbang_interface *bitbang_interface;
/* DANGER!!!! clock absolutely *MUST* be 0 in idle or reset won't work!
return retval;
}
+
+
+bool swd_mode;
+static int queued_retval;
+
+static int bitbang_swd_init(void)
+{
+ LOG_DEBUG("bitbang_swd_init");
+ swd_mode = true;
+ return ERROR_OK;
+}
+
+static void bitbang_exchange(bool rnw, uint8_t buf[], unsigned int offset, unsigned int bit_cnt)
+{
+ LOG_DEBUG("bitbang_exchange");
+ int tdi;
+
+ for (unsigned int i = offset; i < bit_cnt + offset; i++) {
+ int bytec = i/8;
+ int bcval = 1 << (i % 8);
+ tdi = !rnw && (buf[bytec] & bcval);
+
+ bitbang_interface->write(0, 0, tdi);
+
+ if (rnw && buf) {
+ if (bitbang_interface->swdio_read())
+ buf[bytec] |= bcval;
+ else
+ buf[bytec] &= ~bcval;
+ }
+
+ bitbang_interface->write(1, 0, tdi);
+ }
+}
+
+int bitbang_swd_switch_seq(enum swd_special_seq seq)
+{
+ LOG_DEBUG("bitbang_swd_switch_seq");
+
+ switch (seq) {
+ case LINE_RESET:
+ LOG_DEBUG("SWD line reset");
+ bitbang_exchange(false, (uint8_t *)swd_seq_line_reset, 0, swd_seq_line_reset_len);
+ break;
+ case JTAG_TO_SWD:
+ LOG_DEBUG("JTAG-to-SWD");
+ bitbang_exchange(false, (uint8_t *)swd_seq_jtag_to_swd, 0, swd_seq_jtag_to_swd_len);
+ break;
+ case SWD_TO_JTAG:
+ LOG_DEBUG("SWD-to-JTAG");
+ bitbang_exchange(false, (uint8_t *)swd_seq_swd_to_jtag, 0, swd_seq_swd_to_jtag_len);
+ break;
+ default:
+ LOG_ERROR("Sequence %d not supported", seq);
+ return ERROR_FAIL;
+ }
+
+ return ERROR_OK;
+}
+
+void bitbang_switch_to_swd(void)
+{
+ LOG_DEBUG("bitbang_switch_to_swd");
+ bitbang_exchange(false, (uint8_t *)swd_seq_jtag_to_swd, 0, swd_seq_jtag_to_swd_len);
+}
+
+static void swd_clear_sticky_errors(void)
+{
+ bitbang_swd_write_reg(swd_cmd(false, false, DP_ABORT),
+ STKCMPCLR | STKERRCLR | WDERRCLR | ORUNERRCLR, 0);
+}
+
+static void bitbang_swd_read_reg(uint8_t cmd, uint32_t *value, uint32_t ap_delay_clk)
+{
+ LOG_DEBUG("bitbang_swd_read_reg");
+ assert(cmd & SWD_CMD_RnW);
+
+ if (queued_retval != ERROR_OK) {
+ LOG_DEBUG("Skip bitbang_swd_read_reg because queued_retval=%d", queued_retval);
+ return;
+ }
+
+ for (;;) {
+ uint8_t trn_ack_data_parity_trn[DIV_ROUND_UP(4 + 3 + 32 + 1 + 4, 8)];
+
+ cmd |= SWD_CMD_START | (1 << 7);
+ bitbang_exchange(false, &cmd, 0, 8);
+
+ bitbang_interface->swdio_drive(false);
+ bitbang_exchange(true, trn_ack_data_parity_trn, 0, 1 + 3 + 32 + 1 + 1);
+ bitbang_interface->swdio_drive(true);
+
+ int ack = buf_get_u32(trn_ack_data_parity_trn, 1, 3);
+ uint32_t data = buf_get_u32(trn_ack_data_parity_trn, 1 + 3, 32);
+ int parity = buf_get_u32(trn_ack_data_parity_trn, 1 + 3 + 32, 1);
+
+ LOG_DEBUG("%s %s %s reg %X = %08"PRIx32,
+ ack == SWD_ACK_OK ? "OK" : ack == SWD_ACK_WAIT ? "WAIT" : ack == SWD_ACK_FAULT ? "FAULT" : "JUNK",
+ cmd & SWD_CMD_APnDP ? "AP" : "DP",
+ cmd & SWD_CMD_RnW ? "read" : "write",
+ (cmd & SWD_CMD_A32) >> 1,
+ data);
+
+ switch (ack) {
+ case SWD_ACK_OK:
+ if (parity != parity_u32(data)) {
+ LOG_DEBUG("Wrong parity detected");
+ queued_retval = ERROR_FAIL;
+ return;
+ }
+ if (value)
+ *value = data;
+ if (cmd & SWD_CMD_APnDP)
+ bitbang_exchange(true, NULL, 0, ap_delay_clk);
+ return;
+ case SWD_ACK_WAIT:
+ LOG_DEBUG("SWD_ACK_WAIT");
+ swd_clear_sticky_errors();
+ break;
+ case SWD_ACK_FAULT:
+ LOG_DEBUG("SWD_ACK_FAULT");
+ queued_retval = ack;
+ return;
+ default:
+ LOG_DEBUG("No valid acknowledge: ack=%d", ack);
+ queued_retval = ack;
+ return;
+ }
+ }
+}
+
+static void bitbang_swd_write_reg(uint8_t cmd, uint32_t value, uint32_t ap_delay_clk)
+{
+ LOG_DEBUG("bitbang_swd_write_reg");
+ assert(!(cmd & SWD_CMD_RnW));
+
+ if (queued_retval != ERROR_OK) {
+ LOG_DEBUG("Skip bitbang_swd_write_reg because queued_retval=%d", queued_retval);
+ return;
+ }
+
+ for (;;) {
+ uint8_t trn_ack_data_parity_trn[DIV_ROUND_UP(4 + 3 + 32 + 1 + 4, 8)];
+ buf_set_u32(trn_ack_data_parity_trn, 1 + 3 + 1, 32, value);
+ buf_set_u32(trn_ack_data_parity_trn, 1 + 3 + 1 + 32, 1, parity_u32(value));
+
+ cmd |= SWD_CMD_START | (1 << 7);
+ bitbang_exchange(false, &cmd, 0, 8);
+
+ bitbang_interface->swdio_drive(false);
+ bitbang_exchange(true, trn_ack_data_parity_trn, 0, 1 + 3 + 1);
+ bitbang_interface->swdio_drive(true);
+ bitbang_exchange(false, trn_ack_data_parity_trn, 1 + 3 + 1, 32 + 1);
+
+ int ack = buf_get_u32(trn_ack_data_parity_trn, 1, 3);
+ LOG_DEBUG("%s %s %s reg %X = %08"PRIx32,
+ ack == SWD_ACK_OK ? "OK" : ack == SWD_ACK_WAIT ? "WAIT" : ack == SWD_ACK_FAULT ? "FAULT" : "JUNK",
+ cmd & SWD_CMD_APnDP ? "AP" : "DP",
+ cmd & SWD_CMD_RnW ? "read" : "write",
+ (cmd & SWD_CMD_A32) >> 1,
+ buf_get_u32(trn_ack_data_parity_trn, 1 + 3 + 1, 32));
+
+ switch (ack) {
+ case SWD_ACK_OK:
+ if (cmd & SWD_CMD_APnDP)
+ bitbang_exchange(true, NULL, 0, ap_delay_clk);
+ return;
+ case SWD_ACK_WAIT:
+ LOG_DEBUG("SWD_ACK_WAIT");
+ swd_clear_sticky_errors();
+ break;
+ case SWD_ACK_FAULT:
+ LOG_DEBUG("SWD_ACK_FAULT");
+ queued_retval = ack;
+ return;
+ default:
+ LOG_DEBUG("No valid acknowledge: ack=%d", ack);
+ queued_retval = ack;
+ return;
+ }
+ }
+}
+
+static int bitbang_swd_run_queue(void)
+{
+ LOG_DEBUG("bitbang_swd_run_queue");
+ /* A transaction must be followed by another transaction or at least 8 idle cycles to
+ * ensure that data is clocked through the AP. */
+ bitbang_exchange(true, NULL, 0, 8);
+
+ int retval = queued_retval;
+ queued_retval = ERROR_OK;
+ LOG_DEBUG("SWD queue return value: %02x", retval);
+ return retval;
+}
+
+const struct swd_driver bitbang_swd = {
+ .init = bitbang_swd_init,
+ .switch_seq = bitbang_swd_switch_seq,
+ .read_reg = bitbang_swd_read_reg,
+ .write_reg = bitbang_swd_write_reg,
+ .run = bitbang_swd_run_queue,
+};
projects / fw / openocd / blobdiff