From de735d375b979377e124dc2daf1a5f473de19d81 Mon Sep 17 00:00:00 2001 From: Jonas Horberg Date: Thu, 12 Nov 2009 12:39:37 -0800 Subject: parport: add support for the jtag_khz command. Add the khz and speed_div functions to the parport interface driver. Add the parport_toggling_time function that tells the parport driver how long (in nanoseconds) it takes for the hardware to toggle TCK. [dbrownell@users.sourceforge.net: tweak doc for clarity, mention multimeter, and whitespace fixes] Signed-off-by: David Brownell --- src/jtag/parport.c | 72 ++++++++++++++++++++++++++++++++++++++++++++++++------ 1 file changed, 64 insertions(+), 8 deletions(-) (limited to 'src') diff --git a/src/jtag/parport.c b/src/jtag/parport.c index fdf7df4d..9b202902 100644 --- a/src/jtag/parport.c +++ b/src/jtag/parport.c @@ -105,6 +105,8 @@ static cable_t cables[] = static char* parport_cable = NULL; static uint16_t parport_port; static int parport_exit = 0; +static uint32_t parport_toggling_time_ns = 1000; +static int wait_states; /* interface variables */ @@ -152,7 +154,7 @@ static __inline__ void parport_write_data(void) static void parport_write(int tck, int tms, int tdi) { - int i = jtag_get_speed() + 1; + int i = wait_states + 1; if (tck) dataport_value |= cable->TCK_MASK; @@ -204,6 +206,26 @@ static void parport_led(int on) static int parport_speed(int speed) { + wait_states = speed; + return ERROR_OK; +} + +static int parport_khz(int khz, int* jtag_speed) +{ + if (khz == 0) { + LOG_DEBUG("RCLK not supported"); + return ERROR_FAIL; + } + + *jtag_speed = 499999 / (khz * parport_toggling_time_ns); + return ERROR_OK; +} + +static int parport_speed_div(int speed, int* khz) +{ + uint32_t denominator = (speed + 1) * parport_toggling_time_ns; + + *khz = (499999 + denominator) / denominator; return ERROR_OK; } @@ -364,6 +386,8 @@ static int parport_init(void) bitbang_interface = &parport_bitbang; + wait_states = jtag_get_speed(); + return ERROR_OK; } @@ -438,6 +462,32 @@ static int parport_handle_write_on_exit_command(struct command_context_s *cmd_ct return ERROR_OK; } +static int +parport_handle_parport_toggling_time_command(struct command_context_s *cmd_ctx, + char *cmd, char **args, int argc) +{ + if (argc == 1) { + uint32_t ns; + int retval = parse_u32(args[0], &ns); + + if (ERROR_OK != retval) + return retval; + + if (ns == 0) { + LOG_ERROR("0 ns is not a valid parport toggling time"); + return ERROR_FAIL; + } + + parport_toggling_time_ns = ns; + wait_states = jtag_get_speed(); + } + + command_print(cmd_ctx, "parport toggling time = %" PRIu32 " ns", + parport_toggling_time_ns); + + return ERROR_OK; +} + static int parport_register_commands(struct command_context_s *cmd_ctx) { register_command(cmd_ctx, NULL, "parport_port", @@ -455,14 +505,20 @@ static int parport_register_commands(struct command_context_s *cmd_ctx) "configure the parallel driver to write " "a known value to the parallel interface"); + register_command(cmd_ctx, NULL, "parport_toggling_time", + parport_handle_parport_toggling_time_command, COMMAND_ANY, + "time it takes for the hardware to toggle TCK"); + return ERROR_OK; } jtag_interface_t parport_interface = { - .name = "parport", - .register_commands = &parport_register_commands, - .init = &parport_init, - .quit = &parport_quit, - .speed = &parport_speed, - .execute_queue = &bitbang_execute_queue, - }; + .name = "parport", + .register_commands = parport_register_commands, + .init = parport_init, + .quit = parport_quit, + .khz = parport_khz, + .speed_div = parport_speed_div, + .speed = parport_speed, + .execute_queue = bitbang_execute_queue, +}; -- cgit v1.2.3