Expose jtag_unregister_event_callback with related API declarations.
[fw/openocd] / src / jtag / presto.c
index 95c59303b0d68fa936a1857a07f66369c0659408..125658be5b8a6977656399c8b521215c91b961a9 100644 (file)
 
 #if IS_CYGWIN == 1
 #include "windows.h"
-#undef ERROR
 #endif
 
-#include "replacements.h"
-
-/* project specific includes */
-#include "log.h"
-#include "types.h"
-#include "jtag.h"
-#include "configuration.h"
+#include "interface.h"
 #include "time_support.h"
 #include "bitq.h"
 
-/* system includes */
-#include <string.h>
-#include <stdlib.h>
-#include <unistd.h>
-
-#include <sys/time.h>
-#include <time.h>
-
-#include "ftd2xx.h"
 
+/* PRESTO access library includes */
+#if BUILD_PRESTO_FTD2XX == 1
+#include <ftd2xx.h>
+#elif BUILD_PRESTO_LIBFTDI == 1
+#include <ftdi.h>
+#else
+#error "BUG: either FTD2XX and LIBFTDI has to be used"
+#endif
 
-int presto_jtag_speed(int speed);
-int presto_jtag_register_commands(struct command_context_s *cmd_ctx);
-int presto_jtag_init(void);
-int presto_jtag_quit(void);
+static int presto_jtag_speed(int speed);
+static int presto_jtag_khz(int khz, int *jtag_speed);
+static int presto_jtag_speed_div(int speed, int *khz);
+static int presto_jtag_register_commands(struct command_context_s *cmd_ctx);
+static int presto_jtag_init(void);
+static int presto_jtag_quit(void);
 
 jtag_interface_t presto_interface =
 {
        .name = "presto",
        .execute_queue = bitq_execute_queue,
-       .support_pathmove = 1,
        .speed = presto_jtag_speed,
+       .khz = presto_jtag_khz,
+       .speed_div = presto_jtag_speed_div,
        .register_commands = presto_jtag_register_commands,
        .init = presto_jtag_init,
        .quit = presto_jtag_quit,
 };
 
+static int presto_bitq_out(int tms, int tdi, int tdo_req);
+static int presto_bitq_flush(void);
+static int presto_bitq_sleep(unsigned long us);
+static int presto_bitq_reset(int trst, int srst);
+static int presto_bitq_in_rdy(void);
+static int presto_bitq_in(void);
 
-int presto_bitq_out(int tms, int tdi, int tdo_req);
-int presto_bitq_flush(void);
-int presto_bitq_sleep(unsigned long us);
-int presto_bitq_reset(int rst, int en);
-int presto_bitq_in_rdy(void);
-int presto_bitq_in(void);
-
-bitq_interface_t presto_bitq =
+static bitq_interface_t presto_bitq =
 {
        .out = presto_bitq_out,
        .flush = presto_bitq_flush,
@@ -81,33 +75,33 @@ bitq_interface_t presto_bitq =
        .in = presto_bitq_in,
 };
 
-
 /* -------------------------------------------------------------------------- */
 
-
 #define FT_DEVICE_NAME_LEN 64
 #define FT_DEVICE_SERNUM_LEN 64
 
 #define PRESTO_VID_PID 0x0403f1a0
-
-#define PRST_OK 0
-#define PRST_ERR 1
-#define PRST_TIMEOUT 2
+#define PRESTO_VID (0x0403)
+#define PRESTO_PID (0xf1a0)
 
 #define BUFFER_SIZE (64*62)
 
-
 typedef struct presto_s
 {
+#if BUILD_PRESTO_FTD2XX == 1
        FT_HANDLE handle;
        FT_STATUS status;
-       
+#elif BUILD_PRESTO_LIBFTDI == 1
+       struct ftdi_context ftdic;
+       int retval;
+#endif
+
        char serial[FT_DEVICE_SERNUM_LEN];
 
-       BYTE buff_out[BUFFER_SIZE];
+       u8 buff_out[BUFFER_SIZE];
        int buff_out_pos;
 
-       BYTE buff_in[BUFFER_SIZE];
+       u8 buff_in[BUFFER_SIZE];
        int buff_in_exp; /* expected in buffer length */
        int buff_in_len; /* length of data received */
        int buff_in_pos;
@@ -117,382 +111,698 @@ typedef struct presto_s
 
        int jtag_tms; /* last tms state */
        int jtag_tck; /* last tck state */
+       int jtag_rst; /* last trst state */
 
        int jtag_tdi_data;
        int jtag_tdi_count;
 
+       int jtag_speed;
+
 } presto_t;
 
-presto_t presto_state;
-presto_t *presto=&presto_state;
+static presto_t presto_state;
+static presto_t *presto = &presto_state;
 
-BYTE presto_init_seq[] =
+static u8 presto_init_seq[] =
 {
-       0x80,   0xA0,   0xA8,   0xB0,   0xC0,   0xE0
+       0x80, 0xA0, 0xA8, 0xB0, 0xC0, 0xE0
 };
 
+static int presto_write(u8 *buf, u32 size)
+{
+#if BUILD_PRESTO_FTD2XX == 1
+       DWORD ftbytes;
+       if ((presto->status = FT_Write(presto->handle, buf, size, &ftbytes)) != FT_OK)
+       {
+               LOG_ERROR("FT_Write returned: %lu", presto->status);
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
+
+#elif BUILD_PRESTO_LIBFTDI == 1
+       u32 ftbytes;
+       if ((presto->retval = ftdi_write_data(&presto->ftdic, buf, size)) < 0)
+       {
+               LOG_ERROR("ftdi_write_data: %s", ftdi_get_error_string(&presto->ftdic));
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
+       ftbytes = presto->retval;
+#endif
+
+       if (ftbytes != size)
+       {
+               LOG_ERROR("couldn't write the requested number of bytes to PRESTO (%u < %u)", (u32)ftbytes, size);
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
 
-int presto_open(char *req_serial)
+       return ERROR_OK;
+}
+
+static int presto_read(u8* buf, u32 size)
 {
-       int i;
+#if BUILD_PRESTO_FTD2XX == 1
+       DWORD ftbytes;
+       if ((presto->status = FT_Read(presto->handle, buf, size, &ftbytes)) != FT_OK)
+       {
+               LOG_ERROR("FT_Read returned: %lu", presto->status);
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
+
+#elif BUILD_PRESTO_LIBFTDI == 1
+       u32 ftbytes = 0;
+
+       struct timeval timeout, now;
+       gettimeofday(&timeout, NULL);
+       timeval_add_time(&timeout, 1, 0); /* one second timeout */
+
+       while (ftbytes < size)
+       {
+               if ((presto->retval = ftdi_read_data(&presto->ftdic, buf + ftbytes, size - ftbytes)) < 0)
+               {
+                       LOG_ERROR("ftdi_read_data: %s", ftdi_get_error_string(&presto->ftdic));
+                       return ERROR_JTAG_DEVICE_ERROR;
+               }
+               ftbytes += presto->retval;
+
+               gettimeofday(&now, NULL);
+               if ((now.tv_sec > timeout.tv_sec) || ((now.tv_sec == timeout.tv_sec) && (now.tv_usec > timeout.tv_usec)))
+                       break;
+       }
+#endif
+
+       if (ftbytes != size)
+       {
+               /* this is just a warning, there might have been timeout when detecting PRESTO, which is not fatal */
+               LOG_WARNING("couldn't read the requested number of bytes from PRESTO (%u < %u)", (u32)ftbytes, size);
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
+
+       return ERROR_OK;
+}
+
+#if BUILD_PRESTO_FTD2XX == 1
+static int presto_open_ftd2xx(char *req_serial)
+{
+       u32 i;
        DWORD numdevs;
        DWORD vidpid;
        char devname[FT_DEVICE_NAME_LEN];
        FT_DEVICE device;
 
        BYTE presto_data;
-       unsigned long ftbytes;
+       DWORD ftbytes;
 
        presto->handle = (FT_HANDLE)INVALID_HANDLE_VALUE;
 
-       presto->buff_out_pos=0;
-       presto->buff_in_pos=0;
-       presto->buff_in_len=0;
-       presto->buff_in_exp=0;
-
-       presto->total_out=0;
-       presto->total_in=0;
+#if IS_WIN32 == 0
+       /* Add non-standard Vid/Pid to the linux driver */
+       if ((presto->status = FT_SetVIDPID(PRESTO_VID, PRESTO_PID)) != FT_OK)
+       {
+               LOG_ERROR("couldn't add PRESTO VID/PID");
+               exit(-1);
+       }
+#endif
 
-       presto->jtag_tms=0;
-       presto->jtag_tck=0;
-       presto->jtag_tdi_data=0;
-       presto->jtag_tdi_count=0;
+       if ((presto->status = FT_ListDevices(&numdevs, NULL, FT_LIST_NUMBER_ONLY)) != FT_OK)
+       {
+               LOG_ERROR("FT_ListDevices failed: %i", (int)presto->status);
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
 
-       if (FT_ListDevices(&numdevs, NULL, FT_LIST_NUMBER_ONLY)!=FT_OK) return PRST_ERR;
-       for (i=0; i<numdevs; i++)
+       LOG_DEBUG("FTDI devices available: %lu", numdevs);
+       for (i = 0; i < numdevs; i++)
        {
-               if (FT_Open(i, &(presto->handle))!=FT_OK) continue;
-               if (FT_GetDeviceInfo(presto->handle,&device,&vidpid,presto->serial,devname,NULL)==FT_OK)
+               if ((presto->status = FT_Open(i, &(presto->handle))) != FT_OK)
+               {
+                       /* this is not fatal, the device may be legitimately open by other process, hence debug message only */
+                       LOG_DEBUG("FT_Open failed: %i", (int)presto->status);
+                       continue;
+               }
+               LOG_DEBUG("FTDI device %i open", i);
+
+               if ((presto->status = FT_GetDeviceInfo(presto->handle, &device, &vidpid,
+                               presto->serial, devname, NULL)) == FT_OK)
                {
-                       if (vidpid==PRESTO_VID_PID && (req_serial==NULL || !strcmp(presto->serial,req_serial)))
+                       if (vidpid == PRESTO_VID_PID
+                                       && (req_serial == NULL || !strcmp(presto->serial, req_serial)))
                                break;
                }
+               else
+                       LOG_DEBUG("FT_GetDeviceInfo failed: %lu", presto->status);
+
+               LOG_DEBUG("FTDI device %i does not match, closing", i);
                FT_Close(presto->handle);
                presto->handle = (FT_HANDLE)INVALID_HANDLE_VALUE;
        }
 
-       if (presto->handle == (FT_HANDLE)INVALID_HANDLE_VALUE) return PRST_ERR;
+       if (presto->handle == (FT_HANDLE)INVALID_HANDLE_VALUE)
+               return ERROR_JTAG_DEVICE_ERROR; /* presto not open, return */
+
+       if ((presto->status = FT_SetLatencyTimer(presto->handle, 1)) != FT_OK)
+               return ERROR_JTAG_DEVICE_ERROR;
 
-       if ((presto->status=FT_SetLatencyTimer(presto->handle,1))!=FT_OK) return PRST_ERR;
-       if ((presto->status=FT_SetTimeouts(presto->handle,100,0))!=FT_OK) return PRST_ERR;
-       if ((presto->status=FT_Purge(presto->handle, FT_PURGE_TX|FT_PURGE_RX))!=FT_OK) return PRST_ERR;
 
-       presto_data=0xD0;
-       if ((presto->status=FT_Write(presto->handle,&presto_data,1,&ftbytes))!=FT_OK) return PRST_ERR;
-       if ((presto->status=FT_Read(presto->handle,&presto_data,1,&ftbytes))!=FT_OK) return PRST_ERR;
+       if ((presto->status = FT_SetTimeouts(presto->handle, 100, 0)) != FT_OK)
+               return ERROR_JTAG_DEVICE_ERROR;
+
+       if ((presto->status = FT_Purge(presto->handle, FT_PURGE_TX | FT_PURGE_RX)) != FT_OK)
+               return ERROR_JTAG_DEVICE_ERROR;
+
+       presto_data = 0xD0;
+       if ((presto->status = FT_Write(presto->handle, &presto_data, 1, &ftbytes)) != FT_OK)
+               return ERROR_JTAG_DEVICE_ERROR;
+
+       /* delay between first write/read turnaround (after purge?) necessary under Linux for unknown reason,
+          probably a bug in library threading */
+       usleep(100000);
+       if ((presto->status = FT_Read(presto->handle, &presto_data, 1, &ftbytes)) != FT_OK)
+               return ERROR_JTAG_DEVICE_ERROR;
 
        if (ftbytes!=1)
        {
-               if ((presto->status=FT_SetBitMode(presto->handle,0x80,1))!=FT_OK) return PRST_ERR;
-               if ((presto->status=FT_Purge(presto->handle, FT_PURGE_TX|FT_PURGE_RX))!=FT_OK) return PRST_ERR ;
-               if ((presto->status=FT_SetBaudRate(presto->handle,9600))!=FT_OK) return PRST_ERR;
+               LOG_DEBUG("PRESTO reset");
 
-               presto_data=0;
-               for (i=0; i<4*62; i++)
-                       if ((presto->status=FT_Write(presto->handle,&presto_data,1,&ftbytes))!=FT_OK) return PRST_ERR;
+               if ((presto->status = FT_Purge(presto->handle, FT_PURGE_TX | FT_PURGE_RX)) != FT_OK)
+                       return ERROR_JTAG_DEVICE_ERROR;
+               if ((presto->status = FT_SetBitMode(presto->handle, 0x80, 1)) != FT_OK)
+                       return ERROR_JTAG_DEVICE_ERROR;
+               if ((presto->status = FT_SetBaudRate(presto->handle, 9600)) != FT_OK)
+                       return ERROR_JTAG_DEVICE_ERROR;
 
-               usleep(100000);
+               presto_data = 0;
+               for (i = 0; i < 4 * 62; i++)
+                       if ((presto->status=FT_Write(presto->handle, &presto_data, 1, &ftbytes)) != FT_OK)
+                               return ERROR_JTAG_DEVICE_ERROR;
 
-               if ((presto->status=FT_SetBitMode(presto->handle,0x00,0))!=FT_OK) return PRST_ERR;
-               if ((presto->status=FT_Purge(presto->handle, FT_PURGE_TX|FT_PURGE_RX))!=FT_OK) return PRST_ERR;
+               usleep(100000);
 
-               presto_data=0xD0;
-               if ((presto->status=FT_Write(presto->handle,&presto_data,1,&ftbytes))!=FT_OK) return PRST_ERR;
-               if ((presto->status=FT_Read(presto->handle,&presto_data,1,&ftbytes))!=FT_OK) return PRST_ERR;
-               if (ftbytes!=1) return PRST_ERR;
-       }
+               if ((presto->status = FT_SetBitMode(presto->handle, 0x00, 0)) != FT_OK)
+                       return ERROR_JTAG_DEVICE_ERROR;
 
-       if ((presto->status=FT_SetTimeouts(presto->handle,0,0))!=FT_OK) return PRST_ERR;
+               if ((presto->status = FT_Purge(presto->handle, FT_PURGE_TX | FT_PURGE_RX)) != FT_OK)
+                       return ERROR_JTAG_DEVICE_ERROR;
 
-       presto->status=FT_Write(presto->handle,&presto_init_seq,sizeof(presto_init_seq),&ftbytes);
-       if (presto->status!=FT_OK) return PRST_ERR;
-       if (ftbytes!=sizeof(presto_init_seq)) return PRST_TIMEOUT;
+               presto_data = 0xD0;
+               if ((presto->status = FT_Write(presto->handle, &presto_data, 1, &ftbytes)) != FT_OK)
+                       return ERROR_JTAG_DEVICE_ERROR;
 
-       return PRST_OK;
-}
+               /* delay between first write/read turnaround (after purge?) necessary under Linux for unknown reason,
+                  probably a bug in library threading */
+               usleep(100000);
+               if ((presto->status = FT_Read(presto->handle, &presto_data, 1, &ftbytes)) != FT_OK)
+                       return ERROR_JTAG_DEVICE_ERROR;
 
+               if (ftbytes!=1)
+               {
+                       LOG_DEBUG("PRESTO not responding");
+                       return ERROR_JTAG_DEVICE_ERROR;
+               }
+       }
 
-int presto_close(void)
-{
-       unsigned long ftbytes;
+       if ((presto->status = FT_SetTimeouts(presto->handle, 0, 0)) != FT_OK)
+               return ERROR_JTAG_DEVICE_ERROR;
 
-       int result=PRST_OK;
 
-       if (presto->handle == (FT_HANDLE)INVALID_HANDLE_VALUE) return result;
+       presto->status = FT_Write(presto->handle, &presto_init_seq, sizeof(presto_init_seq), &ftbytes);
+       if (presto->status != FT_OK || ftbytes != sizeof(presto_init_seq))
+               return ERROR_JTAG_DEVICE_ERROR;
 
-       presto->status=FT_Write(presto->handle,&presto_init_seq,sizeof(presto_init_seq),&ftbytes);
-       if (presto->status!=FT_OK) result=PRST_ERR;
-       if (ftbytes!=sizeof(presto_init_seq)) result=PRST_TIMEOUT;
+       return ERROR_OK;
+}
 
-       if ((presto->status=FT_SetLatencyTimer(presto->handle,16))!=FT_OK) result=PRST_ERR;
+#elif BUILD_PRESTO_LIBFTDI == 1
+static int presto_open_libftdi(char *req_serial)
+{
+       u8 presto_data;
 
-       if ((presto->status=FT_Close(presto->handle))!=FT_OK) result=PRST_ERR;
-       else presto->handle = (FT_HANDLE)INVALID_HANDLE_VALUE;
+       LOG_DEBUG("searching for PRESTO using libftdi");
 
-       return result;
-}
+       /* initialize FTDI context structure */
+       if (ftdi_init(&presto->ftdic) < 0)
+       {
+               LOG_ERROR("unable to init libftdi: %s", presto->ftdic.error_str);
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
 
+       /* context, vendor id, product id */
+       if (ftdi_usb_open_desc(&presto->ftdic, PRESTO_VID, PRESTO_PID, NULL, req_serial) < 0)
+       {
+               LOG_ERROR("unable to open PRESTO: %s", presto->ftdic.error_str);
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
 
-int presto_flush(void)
-{
-       unsigned long ftbytes;
+       if (ftdi_usb_reset(&presto->ftdic) < 0)
+       {
+               LOG_ERROR("unable to reset PRESTO device");
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
 
-       if (presto->buff_out_pos==0) return PRST_OK;
-       if (presto->status!=FT_OK) return PRST_ERR;
+       if (ftdi_set_latency_timer(&presto->ftdic, 1) < 0)
+       {
+               LOG_ERROR("unable to set latency timer");
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
 
-       if ((presto->status=FT_Write(presto->handle, presto->buff_out, presto->buff_out_pos, &ftbytes))!=FT_OK)
+       if (ftdi_usb_purge_buffers(&presto->ftdic) < 0)
        {
-               presto->buff_out_pos=0;
-               return PRST_ERR;
+               LOG_ERROR("unable to purge PRESTO buffers");
+               return ERROR_JTAG_DEVICE_ERROR;
        }
 
-       presto->total_out+=ftbytes;
+       presto_data = 0xD0;
+       if (presto_write(&presto_data, 1) != ERROR_OK)
+       {
+               LOG_ERROR("error writing to PRESTO");
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
 
-       if (presto->buff_out_pos!=ftbytes)
+       if (presto_read(&presto_data, 1) != ERROR_OK)
        {
-               presto->buff_out_pos=0;
-               return PRST_TIMEOUT;
+               LOG_DEBUG("no response from PRESTO, retrying");
+
+               if (ftdi_usb_purge_buffers(&presto->ftdic) < 0)
+                       return ERROR_JTAG_DEVICE_ERROR;
+
+               presto_data = 0xD0;
+               if (presto_write(&presto_data, 1) != ERROR_OK)
+                       return ERROR_JTAG_DEVICE_ERROR;
+
+               if (presto_read(&presto_data, 1) != ERROR_OK)
+               {
+                       LOG_ERROR("no response from PRESTO, giving up");
+                       return ERROR_JTAG_DEVICE_ERROR;
+               }
        }
 
-       presto->buff_out_pos=0;
+       if (presto_write(presto_init_seq, sizeof(presto_init_seq)) != ERROR_OK)
+       {
+               LOG_ERROR("error writing PRESTO init sequence");
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
 
-       if (presto->buff_in_exp==0) return PRST_OK;
+       return ERROR_OK;
+}
+#endif /* BUILD_PRESTO_LIBFTDI == 1 */
 
+static int presto_open(char *req_serial)
+{
+       presto->buff_out_pos=0;
        presto->buff_in_pos=0;
        presto->buff_in_len=0;
+       presto->buff_in_exp=0;
 
-       if ((presto->status=FT_Read(presto->handle, presto->buff_in, presto->buff_in_exp, &ftbytes))!=FT_OK)
+       presto->total_out=0;
+       presto->total_in=0;
+
+       presto->jtag_tms=0;
+       presto->jtag_tck=0;
+       presto->jtag_rst=0;
+       presto->jtag_tdi_data=0;
+       presto->jtag_tdi_count=0;
+
+       presto->jtag_speed=0;
+
+#if BUILD_PRESTO_FTD2XX == 1
+       return presto_open_ftd2xx(req_serial);
+#elif BUILD_PRESTO_LIBFTDI == 1
+       return presto_open_libftdi(req_serial);
+#endif
+}
+
+static int presto_close(void)
+{
+
+       int result = ERROR_OK;
+
+#if BUILD_PRESTO_FTD2XX == 1
+       unsigned long ftbytes;
+
+       if (presto->handle == (FT_HANDLE)INVALID_HANDLE_VALUE)
+               return result;
+
+       presto->status = FT_Purge(presto->handle, FT_PURGE_TX | FT_PURGE_RX);
+       if (presto->status != FT_OK)
+               result = ERROR_JTAG_DEVICE_ERROR;
+
+       presto->status = FT_Write(presto->handle, &presto_init_seq, sizeof(presto_init_seq), &ftbytes);
+       if (presto->status != FT_OK || ftbytes != sizeof(presto_init_seq))
+               result = ERROR_JTAG_DEVICE_ERROR;
+
+       if ((presto->status = FT_SetLatencyTimer(presto->handle, 16)) != FT_OK)
+               result = ERROR_JTAG_DEVICE_ERROR;
+
+       if ((presto->status = FT_Close(presto->handle)) != FT_OK)
+               result = ERROR_JTAG_DEVICE_ERROR;
+       else
+               presto->handle = (FT_HANDLE)INVALID_HANDLE_VALUE;
+
+#elif BUILD_PRESTO_LIBFTDI == 1
+
+       if ((presto->retval = ftdi_write_data(&presto->ftdic, presto_init_seq, sizeof(presto_init_seq))) != sizeof(presto_init_seq))
+               result = ERROR_JTAG_DEVICE_ERROR;
+
+       if ((presto->retval = ftdi_set_latency_timer(&presto->ftdic, 16)) < 0)
+               result = ERROR_JTAG_DEVICE_ERROR;
+
+       if ((presto->retval = ftdi_usb_close(&presto->ftdic)) < 0)
+               result = ERROR_JTAG_DEVICE_ERROR;
+       else
+               ftdi_deinit(&presto->ftdic);
+#endif
+
+       return result;
+}
+
+static int presto_flush(void)
+{
+       if (presto->buff_out_pos == 0)
+               return ERROR_OK;
+
+#if BUILD_PRESTO_FTD2XX == 1
+       if (presto->status != FT_OK)
+#elif BUILD_PRESTO_LIBFTDI == 1
+       if (presto->retval < 0)
+#endif
        {
-               presto->buff_in_exp=0;
-               return PRST_ERR;
+               LOG_DEBUG("error in previous communication, canceling I/O operation");
+               return ERROR_JTAG_DEVICE_ERROR;
        }
 
-       presto->total_in+=ftbytes;
+       if (presto_write(presto->buff_out, presto->buff_out_pos) != ERROR_OK)
+       {
+               presto->buff_out_pos = 0;
+               return ERROR_JTAG_DEVICE_ERROR;
+       }
+
+       presto->total_out += presto->buff_out_pos;
+       presto->buff_out_pos = 0;
+
+       if (presto->buff_in_exp == 0)
+               return ERROR_OK;
 
-       if (ftbytes!=presto->buff_in_exp)
+       presto->buff_in_pos = 0;
+       presto->buff_in_len = 0;
+
+       if (presto_read(presto->buff_in, presto->buff_in_exp) != ERROR_OK)
        {
-               presto->buff_in_exp=0;
-               return PRST_TIMEOUT;
+               presto->buff_in_exp = 0;
+               return ERROR_JTAG_DEVICE_ERROR;
        }
 
-       presto->buff_in_len=presto->buff_in_exp;
-       presto->buff_in_exp=0;
+       presto->total_in += presto->buff_in_exp;
+       presto->buff_in_len = presto->buff_in_exp;
+       presto->buff_in_exp = 0;
 
-       return PRST_OK;
+       return ERROR_OK;
 }
 
-
-int presto_sendbyte(int data)
+static int presto_sendbyte(int data)
 {
-       if (data==EOF) return presto_flush();
+       if (data == EOF) return presto_flush();
 
        if (presto->buff_out_pos < BUFFER_SIZE)
        {
-               presto->buff_out[presto->buff_out_pos++]=(BYTE)data;
-               if (((data&0xC0)==0x40) || ((data&0xD0)==0xD0))
+               presto->buff_out[presto->buff_out_pos++] = (u8)data;
+               if (((data & 0xC0) == 0x40) || ((data & 0xD0)== 0xD0))
                        presto->buff_in_exp++;
        }
-       else return PRST_ERR;
+       else
+               return ERROR_JTAG_DEVICE_ERROR;
 
-       if (presto->buff_out_pos >= BUFFER_SIZE) return presto_flush();
-       return PRST_OK;
-}
+#if BUILD_PRESTO_FTD2XX == 1
+       if (presto->buff_out_pos >= BUFFER_SIZE)
+#elif BUILD_PRESTO_LIBFTDI == 1
+       /* libftdi does not do background read, be sure that USB IN buffer does not overflow (128 bytes only!) */
+       if (presto->buff_out_pos >= BUFFER_SIZE || presto->buff_in_exp==128)
+#endif
+               return presto_flush();
 
+       return ERROR_OK;
+}
 
-int presto_getbyte(void)
+#if 0
+static int presto_getbyte(void)
 {
-       if (presto->buff_in_pos<presto->buff_in_len)
+       if (presto->buff_in_pos < presto->buff_in_len)
                return presto->buff_in[presto->buff_in_pos++];
 
-       if (presto->buff_in_exp==0) return -1;
-       if (presto_flush()!=PRST_OK) return -1;
+       if (presto->buff_in_exp == 0)
+               return -1;
+
+       if (presto_flush() != ERROR_OK)
+               return -1;
 
        if (presto->buff_in_pos<presto->buff_in_len)
                return presto->buff_in[presto->buff_in_pos++];
 
        return -1;
 }
-
+#endif
 
 /* -------------------------------------------------------------------------- */
 
-
-int presto_bitq_out(int tms, int tdi, int tdo_req)
+static int presto_tdi_flush(void)
 {
-       unsigned char cmdparam;
+       if (presto->jtag_tdi_count == 0)
+               return 0;
 
-       if (presto->jtag_tck==0)
+       if (presto->jtag_tck == 0)
        {
-               presto_sendbyte(0xA4);
-               presto->jtag_tck=1;
+               LOG_ERROR("BUG: unexpected TAP condition, TCK low");
+               return -1;
        }
 
-       else if (!tdo_req && tms==presto->jtag_tms)
+       presto->jtag_tdi_data |= (presto->jtag_tdi_count - 1) << 4;
+       presto_sendbyte(presto->jtag_tdi_data);
+       presto->jtag_tdi_count = 0;
+       presto->jtag_tdi_data = 0;
+
+       return 0;
+}
+
+static int presto_tck_idle(void)
+{
+       if (presto->jtag_tck == 1)
        {
-               if (presto->jtag_tdi_count==0) presto->jtag_tdi_data=(tdi!=0);
-               else presto->jtag_tdi_data|=(tdi!=0)<<presto->jtag_tdi_count;
-               if (++presto->jtag_tdi_count==4)
-               {
-                       presto->jtag_tdi_data|=(presto->jtag_tdi_count-1)<<4;
-                       presto_sendbyte(presto->jtag_tdi_data);
-                       presto->jtag_tdi_count=0;
-               }
-               return 0;
+               presto_sendbyte(0xCA);
+               presto->jtag_tck = 0;
        }
 
-       if (presto->jtag_tdi_count)
+       return 0;
+}
+
+/* -------------------------------------------------------------------------- */
+
+static int presto_bitq_out(int tms, int tdi, int tdo_req)
+{
+       int i;
+       unsigned char cmd;
+
+       if (presto->jtag_tck == 0)
        {
-               presto->jtag_tdi_data|=(presto->jtag_tdi_count-1)<<4;
-               presto_sendbyte(presto->jtag_tdi_data);
-               presto->jtag_tdi_count=0;
+               presto_sendbyte(0xA4); /* LED idicator - JTAG active */
        }
+       else if (presto->jtag_speed == 0 && !tdo_req && tms == presto->jtag_tms)
+       {
+               presto->jtag_tdi_data |= (tdi != 0) << presto->jtag_tdi_count;
 
-       if (tdi) cmdparam=0x0B;
-       else cmdparam=0x0A;
+               if (++presto->jtag_tdi_count == 4)
+                       presto_tdi_flush();
 
-       presto_sendbyte(0xC0|cmdparam);
+               return 0;
+       }
 
-       if (tms!=presto->jtag_tms)
+       presto_tdi_flush();
+
+       cmd = tdi ? 0xCB : 0xCA;
+       presto_sendbyte(cmd);
+
+       if (tms != presto->jtag_tms)
        {
-               if (tms) presto_sendbyte(0xEC);
-               else presto_sendbyte(0xE8);
-               presto->jtag_tms=tms;
+               presto_sendbyte((tms ? 0xEC : 0xE8) | (presto->jtag_rst ? 0x02 : 0));
+               presto->jtag_tms = tms;
        }
 
-       if (tdo_req) presto_sendbyte(0xD4|cmdparam);
-       else presto_sendbyte(0xC4|cmdparam);
+       /* delay with TCK low */
+       for (i=presto->jtag_speed; i>1; i--)
+               presto_sendbyte(cmd);
+
+       cmd |= 0x04;
+       presto_sendbyte(cmd | (tdo_req ? 0x10 : 0));
+
+       /* delay with TCK high */
+       for (i=presto->jtag_speed; i>1; i--)
+               presto_sendbyte(cmd);
+
+       presto->jtag_tck = 1;
 
        return 0;
 }
 
-
-int presto_bitq_flush(void)
+static int presto_bitq_flush(void)
 {
-       if (presto->jtag_tdi_count)
-       {
-               presto->jtag_tdi_data|=(presto->jtag_tdi_count-1)<<4;
-               presto_sendbyte(presto->jtag_tdi_data);
-               presto->jtag_tdi_count=0;
-       }
+       presto_tdi_flush();
+       presto_tck_idle();
 
-       presto_sendbyte(0xCA);
-       presto->jtag_tck=0;
-
-       presto_sendbyte(0xA0);
+       presto_sendbyte(0xA0); /* LED idicator - JTAG idle */
 
        return presto_flush();
 }
 
-
-int presto_bitq_in_rdy(void)
+static int presto_bitq_in_rdy(void)
 {
-       if (presto->buff_in_pos>=presto->buff_in_len) return 0;
+       if (presto->buff_in_pos>=presto->buff_in_len)
+               return 0;
        return presto->buff_in_len-presto->buff_in_pos;
 }
 
-
-int presto_bitq_in(void)
+static int presto_bitq_in(void)
 {
-       if (presto->buff_in_pos>=presto->buff_in_len) return -1;
+       if (presto->buff_in_pos>=presto->buff_in_len)
+               return -1;
        if (presto->buff_in[presto->buff_in_pos++]&0x08) return 1;
        return 0;
 }
 
-
-int presto_bitq_sleep(unsigned long us)
+static int presto_bitq_sleep(unsigned long us)
 {
        long waits;
 
-       if (us>100000)
+       presto_tdi_flush();
+       presto_tck_idle();
+
+       if (us > 100000)
        {
                presto_bitq_flush();
                jtag_sleep(us);
                return 0;
        }
 
-       waits=us/170+2;
-       while (waits--) presto_sendbyte(0x80);
+       waits = us / 170 + 2;
+       while (waits--)
+               presto_sendbyte(0x80);
 
        return 0;
 }
 
-
-int presto_bitq_reset(int trst, int srst)
+static int presto_bitq_reset(int trst, int srst)
 {
-       unsigned char cmd;
+       presto_tdi_flush();
+       presto_tck_idle();
 
-       cmd=0xE8;
-       if (presto->jtag_tms) cmd|=0x04;
+       /* add a delay after possible TCK transition */
+       presto_sendbyte(0x80);
+       presto_sendbyte(0x80);
 
-       if (trst || srst) cmd|=0x02;
+       presto->jtag_rst = trst || srst;
+       presto_sendbyte((presto->jtag_rst ? 0xEA : 0xE8) | (presto->jtag_tms ? 0x04 : 0));
 
-       presto_sendbyte(cmd);
        return 0;
 }
 
-
 /* -------------------------------------------------------------------------- */
 
+static int presto_jtag_khz(int khz, int *jtag_speed)
+{
+       if (khz < 0)
+       {
+               *jtag_speed=0;
+               return ERROR_INVALID_ARGUMENTS;
+       }
+
+       if (khz >= 3000) *jtag_speed = 0;
+       else *jtag_speed = (1000+khz-1)/khz;
+
+       return 0;
+}
 
-int presto_jtag_speed(int speed)
+static int presto_jtag_speed_div(int speed, int *khz)
 {
-       jtag_speed=speed;
-       return ERROR_OK;
+       if ((speed < 0) || (speed > 1000))
+       {
+               *khz=0;
+               return ERROR_INVALID_ARGUMENTS;
+       }
+
+       if (speed == 0) *khz = 3000;
+       else *khz = 1000/speed;
+
+       return 0;
 }
 
+static int presto_jtag_speed(int speed)
+{
+       int khz;
 
-char *presto_serial;
+       if (presto_jtag_speed_div(speed, &khz))
+       {
+               return ERROR_INVALID_ARGUMENTS;
+       }
+
+       presto->jtag_speed = speed;
+
+       if (khz%1000 == 0)
+               LOG_INFO("setting speed to %d, max. TCK freq. is %d MHz", speed, khz/1000);
+       else
+               LOG_INFO("setting speed to %d, max. TCK freq. is %d kHz", speed, khz);
+
+       return 0;
+}
+
+static char *presto_serial;
 
-int presto_handle_serial_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
+static int presto_handle_serial_command(struct command_context_s *cmd_ctx, char *cmd, char **args, int argc)
 {
        if (argc == 1)
        {
-               if (presto_serial) free(presto_serial);
+               if (presto_serial)
+                       free(presto_serial);
                presto_serial = strdup(args[0]);
        }
        else
        {
-               ERROR("expected exactly one argument to presto_serial <serial-number>");
+               LOG_ERROR("expected exactly one argument to presto_serial <serial-number>");
        }
 
        return ERROR_OK;
 }
 
-
-int presto_jtag_register_commands(struct command_context_s *cmd_ctx)
+static int presto_jtag_register_commands(struct command_context_s *cmd_ctx)
 {
        register_command(cmd_ctx, NULL, "presto_serial", presto_handle_serial_command,
                COMMAND_CONFIG, NULL);
        return ERROR_OK;
 }
 
-
-int presto_jtag_init(void)
+static int presto_jtag_init(void)
 {
-       if (presto_open(presto_serial)!=0)
+       if (presto_open(presto_serial) != ERROR_OK)
        {
                presto_close();
-               if (presto_serial!=NULL) ERROR("Cannot open PRESTO, serial number %s", presto_serial);
-               else ERROR("Cannot open PRESTO");
+               if (presto_serial != NULL)
+                       LOG_ERROR("Cannot open PRESTO, serial number '%s'", presto_serial);
+               else
+                       LOG_ERROR("Cannot open PRESTO");
                return ERROR_JTAG_INIT_FAILED;
        }
-       INFO("PRESTO open, serial number %s", presto->serial);
-       
-       bitq_interface=&presto_bitq;
+       LOG_INFO("PRESTO open, serial number '%s'", presto->serial);
+
+       /* use JTAG speed setting from configuration file */
+       presto_jtag_speed(jtag_get_speed());
+
+       bitq_interface = &presto_bitq;
        return ERROR_OK;
 }
 
-
-int presto_jtag_quit(void)
+static int presto_jtag_quit(void)
 {
        bitq_cleanup();
        presto_close();
-       INFO("PRESTO closed");
+       LOG_INFO("PRESTO closed");
 
        if (presto_serial)
        {
                free(presto_serial);
-               presto_serial=NULL;
+               presto_serial = NULL;
        }
 
        return ERROR_OK;