From 86399a4cdf03803dc04e00140156aeb6a7e9207d Mon Sep 17 00:00:00 2001
From: xenia <xenia@awoo.systems>
Date: Fri, 26 Apr 2024 02:41:04 -0400
Subject: [PATCH] meow meow

---
 lib/dune           |  2 +-
 lib/eio_device.ml  |  0
 lib/eio_serial.ml  | 79 ++++++++++++++++++++++++++++++++++++++++++++++
 lib/eio_serial.mli | 18 +++++++++++
 4 files changed, 98 insertions(+), 1 deletion(-)
 create mode 100644 lib/eio_device.ml
 create mode 100644 lib/eio_serial.mli

diff --git a/lib/dune b/lib/dune
index 5bcf563..26d511e 100644
--- a/lib/dune
+++ b/lib/dune
@@ -1,4 +1,4 @@
 (library
  (name bk910x)
  (public_name bk910x)
- (libraries eio xlog))
+ (libraries eio eio_linux xlog))
diff --git a/lib/eio_device.ml b/lib/eio_device.ml
new file mode 100644
index 0000000..e69de29
diff --git a/lib/eio_serial.ml b/lib/eio_serial.ml
index e69de29..5afa651 100644
--- a/lib/eio_serial.ml
+++ b/lib/eio_serial.ml
@@ -0,0 +1,79 @@
+open Eio.Std
+
+type t = {
+  fd : Eio_unix.Fd.t
+}
+
+type parity =
+| Parity_none
+| Parity_even
+| Parity_odd
+
+type flow_control =
+| Flow_none
+| Flow_software
+| Flow_hardware
+
+(* currently this defaults to Eio_linux. idk of a better way to handle this because there's no high
+   level method to open with O_NOCTTY *)
+
+let make ~(sw : Switch.t) ?(baudrate=115200) ?(bytesize=8) ?(parity=Parity_none) ?(stopbits=1)
+         ?(flowctrl=Flow_none) ?(exclusive=false)
+         (path : _ Eio.Path.t) : t =
+  (* and here we run into our first problem: how do we wrangle a path into an argument to openat *)
+  let path = Eio.Path.native_exn path in
+  let fd =
+    Eio_linux.Low_level.openat ~sw ~access:`RW ~flags:Uring.Open_flags.(cloexec + noctty)
+      ~perm:0 Eio_linux.Low_level.Fs path in
+  (* TODO *)
+  ignore exclusive; (* acquire lock *)
+  Switch.on_release sw (fun () ->
+    (* release lock *)
+    ignore exclusive;
+    Eio_unix.Fd.close fd
+  );
+  Eio_unix.Fd.use_exn "tty setup" fd (fun fd ->
+    let attr = Unix.tcgetattr fd in
+    let attr = {
+      attr with
+      c_clocal = true;
+      c_cread = true;
+      c_icanon = false;
+      c_echo = false;
+      c_echoe = false;
+      c_echok = false;
+      c_echonl = false;
+      c_isig = false;
+      c_opost = false;
+      c_inlcr = false;
+      c_igncr = false;
+      c_icrnl = false;
+      c_ignbrk = false;
+      c_parmrk = false;
+      c_inpck = false;
+      c_istrip = false;
+
+      c_obaud = baudrate;
+      c_ibaud = baudrate;
+      c_csize = bytesize;
+      c_cstopb = stopbits;
+      c_parenb = (parity != Parity_none);
+      c_parodd = (parity == Parity_odd);
+
+      c_ixon = (flowctrl == Flow_software);
+      c_ixoff = (flowctrl == Flow_software);
+
+      (* rtscts is not exposed by ocaml *)
+
+      c_vmin = 0;
+      c_vtime = 0;
+    } in
+    Unix.tcsetattr fd Unix.TCSANOW attr;
+    (* here we'd also reset rstcts and dsrdtr but again.... ocaml... *)
+    Unix.tcflush fd Unix.TCIFLUSH);
+  (* how to convert this into flow...... *)
+  { fd; }
+
+let tcflow (port : t) (action : Unix.flow_action) : unit =
+  Eio_unix.Fd.use_exn "tcflow" port.fd (fun fd ->
+    Unix.tcflow fd action)
diff --git a/lib/eio_serial.mli b/lib/eio_serial.mli
new file mode 100644
index 0000000..8115b51
--- /dev/null
+++ b/lib/eio_serial.mli
@@ -0,0 +1,18 @@
+open Eio.Std
+
+type t
+
+type parity =
+| Parity_none
+| Parity_even
+| Parity_odd
+
+type flow_control =
+| Flow_none
+| Flow_software
+| Flow_hardware
+
+val make : sw:Switch.t -> ?baudrate:int -> ?bytesize:int -> ?parity:parity -> ?stopbits:int ->
+           ?flowctrl:flow_control -> ?exclusive:bool -> _ Eio.Path.t -> t
+
+val tcflow : t -> Unix.flow_action -> unit