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jtag/drivers/cmsis-dap: fix connect under reset 

Commit ef02b69b14 included
a call to cmsis_dap_cmd_DAP_Connect() before calling
cmsis_dap_cmd_DAP_SWJ_Sequence(). According to comment
it is necessary for at least Keil ULINK-ME.

Commit 72c3464be4 added
a cmsis_dap_cmd_DAP_Disconnect() before connect call to pair
connection/disconnection. It solves some problems on Atmel EDBG.

Unfortunately calling either of cmsis_dap_cmd_DAP_Connect()
or cmsis_dap_cmd_DAP_Disconnect() deasserts reset signal.
So these workarounds break ability to connect under reset.

Use cmsis_dap_cmd_DAP_Disconnect() and cmsis_dap_cmd_DAP_Connect()
pair only if both SRST and TRST are deasserted.

Change-Id: I0914dae0a1360b8c7fe48231ff3867caedfb2dbe
Signed-off-by: Tomas Vanek <vanekt@fbl.cz>
Reported-by: Leonardo Sabino dos Santos <leonardo.sabino@gmail.com>
Reviewed-on: http://openocd.zylin.com/4100
Tested-by: jenkins
Reviewed-by: Paul Fertser <fercerpav@gmail.com>
This commit is contained in:
Tomas Vanek 2017-04-09 10:59:57 +02:00 committed by Paul Fertser
parent 1c2e3d41de
commit bb976e3c38
1 changed files with 19 additions and 11 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
src/jtag/drivers/cmsis_dap_usb.c
View File

@ -206,6 +206,8 @@ static uint8_t queued_seq_buf[1024]; /* TODO: make dynamic / move into cmsis obj
static int queued_retval;
static uint8_t output_pins = SWJ_PIN_SRST | SWJ_PIN_TRST;
static struct cmsis_dap *cmsis_dap_handle;
static int cmsis_dap_usb_open(void)
@ -790,6 +792,11 @@ static int cmsis_dap_swd_switch_seq(enum swd_special_seq seq)
unsigned int s_len;
int retval;
if ((output_pins & (SWJ_PIN_SRST | SWJ_PIN_TRST)) == (SWJ_PIN_SRST | SWJ_PIN_TRST)) {
/* Following workaround deasserts reset on most adapters.
* Do not reconnect if a reset line is active!
* Reconnecting would break connecting under reset. */
/* First disconnect before connecting, Atmel EDBG needs it for SAMD/R/L/C */
cmsis_dap_cmd_DAP_Disconnect();
@ -799,6 +806,7 @@ static int cmsis_dap_swd_switch_seq(enum swd_special_seq seq)
CONNECT_SWD : CONNECT_JTAG);
if (retval != ERROR_OK)
return retval;
}
switch (seq) {
case LINE_RESET:
@ -1010,14 +1018,14 @@ static void cmsis_dap_execute_reset(struct jtag_command *cmd)
{
/* Set both TRST and SRST even if they're not enabled as
* there's no way to tristate them */
uint8_t pins = 0;
output_pins = 0;
if (!cmd->cmd.reset->srst)
pins |= SWJ_PIN_SRST;
output_pins |= SWJ_PIN_SRST;
if (!cmd->cmd.reset->trst)
pins |= SWJ_PIN_TRST;
output_pins |= SWJ_PIN_TRST;
int retval = cmsis_dap_cmd_DAP_SWJ_Pins(pins,
int retval = cmsis_dap_cmd_DAP_SWJ_Pins(output_pins,
SWJ_PIN_TRST | SWJ_PIN_SRST, 0, NULL);
if (retval != ERROR_OK)
LOG_ERROR("CMSIS-DAP: Interface reset failed");