Initial push

1 files changed, 251 insertions, 0 deletions

diff --git a/stacks/max25-bcpr/src/bcpr_uart.c b/stacks/max25-bcpr/src/bcpr_uart.c
new file mode 100644
index 0000000..22ccba3
--- /dev/null
+++ b/stacks/max25-bcpr/src/bcpr_uart.c
@@ -0,0 +1,251 @@
+/*
+ * Userspace 8250/16550 register access for SER12 bit-bang.
+ * Prefer ioperm(2); fall back to /dev/port. Dry-run: no-ops.
+ * Algorithms match Linux baycom_ser_fdx (see NOTICE.md).
+ */
+#define _GNU_SOURCE
+#include "bcpr/bcpr_uart.h"
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <string.h>
+#include <sys/types.h>
+#include <time.h>
+#include <unistd.h>
+
+#if defined(__linux__)
+#include <sys/io.h>
+#elif defined(__FreeBSD__)
+#include <machine/cpufunc.h>
+#include <machine/sysarch.h>
+#endif
+
+#if defined(__FreeBSD__)
+static int bcpr_freebsd_set_ioperm(unsigned start, unsigned len, int enable)
+{
+    struct {
+        unsigned int start;
+        unsigned int length;
+        int enable;
+    } args;
+
+    args.start = start;
+    args.length = len;
+    args.enable = enable;
+    return sysarch(I386_SET_IOPERM, &args);
+}
+#endif
+
+static int g_dry;
+static int g_port_fd = -1;
+static int g_ioperm_ok;
+
+void bcpr_uart_set_dry_run(int on)
+{
+    g_dry = on ? 1 : 0;
+}
+
+int bcpr_uart_ioperm(unsigned iobase, int on)
+{
+    if (g_dry) {
+        return 0;
+    }
+#if defined(__linux__)
+    if (ioperm((unsigned long)iobase, 8, on ? 1 : 0) == 0) {
+        g_ioperm_ok = on ? 1 : 0;
+        return 0;
+    }
+#elif defined(__FreeBSD__)
+    /*
+     * Prefer /dev/io (process-wide inb/outb). sysarch range is fallback.
+     * ExSys port: disable matching uart(4) unit (e.g. uart2/cuau2) in
+     * loader.conf — kernel uart + userspace inb on same iobase → SIGBUS.
+     */
+    if (on) {
+        if (g_port_fd < 0) {
+            g_port_fd = open("/dev/io", O_RDWR | O_CLOEXEC);
+        }
+        if (g_port_fd >= 0) {
+            g_ioperm_ok = 1;
+            return 0;
+        }
+    }
+    if (bcpr_freebsd_set_ioperm((unsigned)iobase, 8, on ? 1 : 0) == 0) {
+        g_ioperm_ok = on ? 1 : 0;
+        return 0;
+    }
+#endif
+    /* Fallback: /dev/io (FreeBSD) or /dev/port (Linux) — needs root. */
+    if (on) {
+        if (g_port_fd < 0) {
+#if defined(__FreeBSD__)
+            g_port_fd = open("/dev/io", O_RDWR | O_CLOEXEC);
+#else
+            g_port_fd = open("/dev/port", O_RDWR | O_CLOEXEC);
+#endif
+            if (g_port_fd >= 0) {
+                g_ioperm_ok = 1;
+                return 0;
+            }
+        }
+        if (g_port_fd >= 0) {
+            return 0;
+        }
+        return -1;
+    }
+    if (g_port_fd >= 0) {
+        close(g_port_fd);
+        g_port_fd = -1;
+    }
+    g_ioperm_ok = 0;
+    return 0;
+}
+
+static int port_rw(unsigned port, int do_write, unsigned char *val)
+{
+    off_t off = (off_t)port;
+    if (g_port_fd < 0) {
+        return -1;
+    }
+    if (lseek(g_port_fd, off, SEEK_SET) != off) {
+        return -1;
+    }
+    if (do_write) {
+        return (write(g_port_fd, val, 1) == 1) ? 0 : -1;
+    }
+    return (read(g_port_fd, val, 1) == 1) ? 0 : -1;
+}
+
+void bcpr_uart_outb(unsigned char val, unsigned port)
+{
+    if (g_dry) {
+        return;
+    }
+    if (g_ioperm_ok) {
+        outb(val, port);
+        return;
+    }
+    (void)port_rw(port, 1, &val);
+}
+
+unsigned char bcpr_uart_inb(unsigned port)
+{
+    unsigned char v = 0;
+    if (g_dry) {
+        return 0;
+    }
+    if (g_ioperm_ok) {
+        return inb(port);
+    }
+    (void)port_rw(port, 0, &v);
+    return v;
+}
+
+void bcpr_uart_set_divisor(unsigned iobase, unsigned divisor)
+{
+    unsigned char lcr;
+    if (g_dry) {
+        return;
+    }
+    lcr = bcpr_uart_inb(iobase + 3);
+    bcpr_uart_outb((unsigned char)(lcr | 0x80), iobase + 3); /* DLAB */
+    bcpr_uart_outb((unsigned char)(divisor & 0xff), iobase + 0);
+    bcpr_uart_outb((unsigned char)((divisor >> 8) & 0xff), iobase + 1);
+    bcpr_uart_outb((unsigned char)(lcr & 0x7f), iobase + 3);
+}
+
+void bcpr_uart_open_ser12(unsigned iobase)
+{
+    if (g_dry) {
+        return;
+    }
+    /* Match baycom_ser_fdx open: FIFO off, 6-bit word, IER THRE+MSR. */
+    bcpr_uart_outb(0x00, iobase + 2); /* FCR */
+    bcpr_uart_outb(0x01, iobase + 3); /* LCR 6N1 */
+    bcpr_uart_outb(0x0a, iobase + 1); /* IER */
+    bcpr_uart_outb(0x0d, iobase + 4); /* MCR idle */
+    bcpr_uart_thr00(iobase);
+}
+
+void bcpr_uart_close_ser12(unsigned iobase)
+{
+    if (g_dry) {
+        return;
+    }
+    bcpr_uart_outb(0x00, iobase + 1); /* IER off */
+    bcpr_uart_outb(0x01, iobase + 4); /* MCR close */
+}
+
+unsigned char bcpr_uart_msr(unsigned iobase)
+{
+    if (g_dry) {
+        return 0;
+    }
+    return bcpr_uart_inb(iobase + 6);
+}
+
+void bcpr_uart_mcr(unsigned iobase, unsigned char v)
+{
+    if (g_dry) {
+        return;
+    }
+    bcpr_uart_outb(v, iobase + 4);
+}
+
+void bcpr_uart_thr00(unsigned iobase)
+{
+    if (g_dry) {
+        return;
+    }
+    bcpr_uart_outb(0x00, iobase + 0);
+}
+
+void bcpr_uart_set_break(unsigned iobase, int on)
+{
+    unsigned char lcr;
+    if (g_dry) {
+        return;
+    }
+    /*
+     * 8250 LCR bit6 (Set Break): force TXD to continuous SPACE (RS-232 +V).
+     * Honest limit: THR writes alone cannot hold DC-steady TXD — each byte is
+     * framed (start/data/stop). Break is the practical TFPCX-class approximation
+     * (docs: static ≈ +12 V modem supply). Does not change MCR/PTT.
+     */
+    lcr = bcpr_uart_inb(iobase + 3);
+    if (on) {
+        bcpr_uart_outb((unsigned char)(lcr | 0x40), iobase + 3);
+    } else {
+        bcpr_uart_outb((unsigned char)(lcr & (unsigned char)~0x40), iobase + 3);
+    }
+}
+
+int bcpr_uart_wait_thre(unsigned iobase, unsigned timeout_us)
+{
+    struct timespec t0, now;
+    unsigned char lsr;
+
+    if (g_dry) {
+        return 1;
+    }
+    if (clock_gettime(CLOCK_MONOTONIC, &t0) != 0) {
+        return 0;
+    }
+    for (;;) {
+        lsr = bcpr_uart_inb(iobase + 5);
+        if (lsr & 0x20) { /* THRE */
+            return 1;
+        }
+        if (clock_gettime(CLOCK_MONOTONIC, &now) != 0) {
+            return 0;
+        }
+        {
+            long elapsed = (long)(now.tv_sec - t0.tv_sec) * 1000000L +
+                           (now.tv_nsec - t0.tv_nsec) / 1000L;
+            if (elapsed >= (long)timeout_us) {
+                return 0;
+            }
+        }
+    }
+}