Add read buffer to bitbang, improving performance.
[openocd.git] / src / jtag / drivers / remote_bitbang.c
index c8d013666be188557fb2b334ff4dbb447b35517f..1f8fc1a11e68ccc2ccef2a33b9ac3e118be8b6dd 100644 (file)
 /* arbitrary limit on host name length: */
 #define REMOTE_BITBANG_HOST_MAX 255
 
-#define REMOTE_BITBANG_RAISE_ERROR(expr ...) \
-       do { \
-               LOG_ERROR(expr); \
-               LOG_ERROR("Terminating openocd."); \
-               exit(-1); \
-       } while (0)
-
 static char *remote_bitbang_host;
 static char *remote_bitbang_port;
 
-FILE *remote_bitbang_in;
-FILE *remote_bitbang_out;
+static FILE *remote_bitbang_file;
+static int remote_bitbang_fd;
+
+/* Circular buffer. When start == end, the buffer is empty. */
+static char remote_bitbang_buf[64];
+static unsigned remote_bitbang_start;
+static unsigned remote_bitbang_end;
+
+static int remote_bitbang_buf_full(void)
+{
+       return remote_bitbang_end ==
+               ((remote_bitbang_start + sizeof(remote_bitbang_buf) - 1) %
+                sizeof(remote_bitbang_buf));
+}
 
-static void remote_bitbang_putc(int c)
+/* Read any incoming data, placing it into the buffer. */
+static int remote_bitbang_fill_buf(void)
 {
-       if (EOF == fputc(c, remote_bitbang_out))
-               REMOTE_BITBANG_RAISE_ERROR("remote_bitbang_putc: %s", strerror(errno));
+       socket_nonblock(remote_bitbang_fd);
+       while (!remote_bitbang_buf_full()) {
+               unsigned contiguous_available_space;
+               if (remote_bitbang_end >= remote_bitbang_start) {
+                       contiguous_available_space = sizeof(remote_bitbang_buf) -
+                               remote_bitbang_end;
+                       if (remote_bitbang_start == 0)
+                               contiguous_available_space -= 1;
+               } else {
+                       contiguous_available_space = remote_bitbang_start -
+                               remote_bitbang_end - 1;
+               }
+               ssize_t count = read(remote_bitbang_fd,
+                               remote_bitbang_buf + remote_bitbang_end,
+                               contiguous_available_space);
+               if (count > 0) {
+                       remote_bitbang_end += count;
+                       if (remote_bitbang_end == sizeof(remote_bitbang_buf))
+                               remote_bitbang_end = 0;
+               } else if (count == 0) {
+                       return ERROR_OK;
+               } else if (count < 0) {
+                       if (errno == EAGAIN) {
+                               return ERROR_OK;
+                       } else {
+                               LOG_ERROR("remote_bitbang_fill_buf: %s (%d)",
+                                               strerror(errno), errno);
+                               return ERROR_FAIL;
+                       }
+               }
+       }
+
+       return ERROR_OK;
+}
+
+static int remote_bitbang_putc(int c)
+{
+       if (EOF == fputc(c, remote_bitbang_file)) {
+               LOG_ERROR("remote_bitbang_putc: %s", strerror(errno));
+               return ERROR_FAIL;
+       }
+       return ERROR_OK;
 }
 
 static int remote_bitbang_quit(void)
 {
-       if (EOF == fputc('Q', remote_bitbang_out)) {
+       if (EOF == fputc('Q', remote_bitbang_file)) {
                LOG_ERROR("fputs: %s", strerror(errno));
                return ERROR_FAIL;
        }
 
-       if (EOF == fflush(remote_bitbang_out)) {
+       if (EOF == fflush(remote_bitbang_file)) {
                LOG_ERROR("fflush: %s", strerror(errno));
                return ERROR_FAIL;
        }
 
        /* We only need to close one of the FILE*s, because they both use the same */
        /* underlying file descriptor. */
-       if (EOF == fclose(remote_bitbang_out)) {
+       if (EOF == fclose(remote_bitbang_file)) {
                LOG_ERROR("fclose: %s", strerror(errno));
                return ERROR_FAIL;
        }
@@ -75,53 +121,83 @@ static int remote_bitbang_quit(void)
        return ERROR_OK;
 }
 
-/* Get the next read response. */
-static int remote_bitbang_rread(void)
+static bb_value_t char_to_int(int c)
 {
-       if (EOF == fflush(remote_bitbang_out)) {
-               remote_bitbang_quit();
-               REMOTE_BITBANG_RAISE_ERROR("fflush: %s", strerror(errno));
-       }
-
-       int c = fgetc(remote_bitbang_in);
        switch (c) {
                case '0':
-                       return 0;
+                       return BB_LOW;
                case '1':
-                       return 1;
+                       return BB_HIGH;
                default:
                        remote_bitbang_quit();
-                       REMOTE_BITBANG_RAISE_ERROR(
-                                       "remote_bitbang: invalid read response: %c(%i)", c, c);
+                       LOG_ERROR("remote_bitbang: invalid read response: %c(%i)", c, c);
+                       return BB_ERROR;
+       }
+}
+
+/* Get the next read response. */
+static bb_value_t remote_bitbang_rread(void)
+{
+       if (EOF == fflush(remote_bitbang_file)) {
+               remote_bitbang_quit();
+               LOG_ERROR("fflush: %s", strerror(errno));
+               return BB_ERROR;
+       }
+
+       /* Enable blocking access. */
+       socket_block(remote_bitbang_fd);
+       char c;
+       ssize_t count = read(remote_bitbang_fd, &c, 1);
+       if (count == 1) {
+               return char_to_int(c);
+       } else {
+               remote_bitbang_quit();
+               LOG_ERROR("read: count=%d, error=%s", (int) count, strerror(errno));
+               return BB_ERROR;
        }
 }
 
-static int remote_bitbang_read(void)
+static int remote_bitbang_sample(void)
 {
-       remote_bitbang_putc('R');
+       if (remote_bitbang_fill_buf() != ERROR_OK)
+               return ERROR_FAIL;
+       assert(!remote_bitbang_buf_full());
+       return remote_bitbang_putc('R');
+}
+
+static bb_value_t remote_bitbang_read_sample(void)
+{
+       if (remote_bitbang_start != remote_bitbang_end) {
+               int c = remote_bitbang_buf[remote_bitbang_start];
+               remote_bitbang_start =
+                       (remote_bitbang_start + 1) % sizeof(remote_bitbang_buf);
+               return char_to_int(c);
+       }
        return remote_bitbang_rread();
 }
 
-static void remote_bitbang_write(int tck, int tms, int tdi)
+static int remote_bitbang_write(int tck, int tms, int tdi)
 {
        char c = '0' + ((tck ? 0x4 : 0x0) | (tms ? 0x2 : 0x0) | (tdi ? 0x1 : 0x0));
-       remote_bitbang_putc(c);
+       return remote_bitbang_putc(c);
 }
 
-static void remote_bitbang_reset(int trst, int srst)
+static int remote_bitbang_reset(int trst, int srst)
 {
        char c = 'r' + ((trst ? 0x2 : 0x0) | (srst ? 0x1 : 0x0));
-       remote_bitbang_putc(c);
+       return remote_bitbang_putc(c);
 }
 
-static void remote_bitbang_blink(int on)
+static int remote_bitbang_blink(int on)
 {
        char c = on ? 'B' : 'b';
-       remote_bitbang_putc(c);
+       return remote_bitbang_putc(c);
 }
 
 static struct bitbang_interface remote_bitbang_bitbang = {
-       .read = &remote_bitbang_read,
+       .buf_size = sizeof(remote_bitbang_buf) - 1,
+       .sample = &remote_bitbang_sample,
+       .read_sample = &remote_bitbang_read_sample,
        .write = &remote_bitbang_write,
        .reset = &remote_bitbang_reset,
        .blink = &remote_bitbang_blink,
@@ -131,7 +207,7 @@ static int remote_bitbang_init_tcp(void)
 {
        struct addrinfo hints = { .ai_family = AF_UNSPEC, .ai_socktype = SOCK_STREAM };
        struct addrinfo *result, *rp;
-       int fd;
+       int fd = 0;
 
        LOG_INFO("Connecting to %s:%s",
                        remote_bitbang_host ? remote_bitbang_host : "localhost",
@@ -199,29 +275,24 @@ static int remote_bitbang_init_unix(void)
 
 static int remote_bitbang_init(void)
 {
-       int fd;
        bitbang_interface = &remote_bitbang_bitbang;
 
+       remote_bitbang_start = 0;
+       remote_bitbang_end = 0;
+
        LOG_INFO("Initializing remote_bitbang driver");
        if (remote_bitbang_port == NULL)
-               fd = remote_bitbang_init_unix();
+               remote_bitbang_fd = remote_bitbang_init_unix();
        else
-               fd = remote_bitbang_init_tcp();
+               remote_bitbang_fd = remote_bitbang_init_tcp();
 
-       if (fd < 0)
-               return fd;
-
-       remote_bitbang_in = fdopen(fd, "r");
-       if (remote_bitbang_in == NULL) {
-               LOG_ERROR("fdopen: failed to open read stream");
-               close(fd);
-               return ERROR_FAIL;
-       }
+       if (remote_bitbang_fd < 0)
+               return remote_bitbang_fd;
 
-       remote_bitbang_out = fdopen(fd, "w");
-       if (remote_bitbang_out == NULL) {
+       remote_bitbang_file = fdopen(remote_bitbang_fd, "w+");
+       if (remote_bitbang_file == NULL) {
                LOG_ERROR("fdopen: failed to open write stream");
-               fclose(remote_bitbang_in);
+               close(remote_bitbang_fd);
                return ERROR_FAIL;
        }
 

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