Merge pull request #447 from UncleGrumpy/stm32_gpio

Update stm32 gpio driver

Restores functionality to the stm32 gpio driver by updating mailbox message
parsing to match updates to the the erlang and elixir drivers. Modifies the
`pin() type` in both versions of the gpio driver to accommodate tuples used in
the stm32 port.

These changes are made under both the "Apache 2.0" and the "GNU Lesser General
Public License 2.1 or later" license terms (dual license).

SPDX-License-Identifier: Apache-2.0 OR LGPL-2.1-or-later

libs/eavmlib/src/gpio.erl

@@ -43,6 +43,9 @@
 %%
 %% This module provides functions for interacting with micro-controller GPIO
 %% (General Purpose Input and Output) pins.
+%%
+%% Note: `-type pin()' used in this driver refers to a pin number on Espressif
+%% chips, or a tuple {GPIO_GROUP, PIN} for stm32 chips.
 %% @end
 %%-----------------------------------------------------------------------------
 -module(gpio).
@@ -62,7 +65,7 @@
 ]).
 
 -type gpio() :: pid().
--type pin() :: non_neg_integer().
+-type pin() :: non_neg_integer() | {atom(), non_neg_integer()}.
 -type direction() :: input | output | output_od.
 -type pull() :: up | down | up_down | floating.
 -type low_level() :: low | 0.

libs/exavmlib/lib/GPIO.ex

@@ -28,8 +28,10 @@ defmodule GPIO do
   Valid GPIO pin number.
 
   The actual number of pins that are broken out vary by board and module.
+  For espressif chips this a the pin number marked on the board or data sheet.
+  For stm32 chips this is a tuple {GPIO_GROUP, PIN_NUMBER}.
   """
-  @type gpio_pin() :: non_neg_integer()
+  @type gpio_pin() :: non_neg_integer() | {atom(), non_neg_integer()}
 
   @typedoc """
   Event type describing the voltage that will trigger an interrupt.

src/platforms/stm32/src/lib/gpiodriver.c

@@ -27,6 +27,8 @@
 #include <mailbox.h>
 #include <term.h>
 
+// Uncomment to enable trace
+//#define ENABLE_TRACE 1
 #include <trace.h>
 
 #include "platform_defaultatoms.h"
@@ -36,6 +38,15 @@ static uint32_t port_atom_to_gpio_port(Context *ctx, term port_atom);
 static uint16_t gpio_port_to_rcc_port(uint32_t gpio_port);
 static char gpio_port_to_name(uint32_t gpio_port);
 
+static term create_pair(Context *ctx, term term1, term term2)
+{
+    term ret = term_alloc_tuple(2, ctx);
+    term_put_tuple_element(ret, 0, term1);
+    term_put_tuple_element(ret, 1, term2);
+
+    return ret;
+}
+
 void gpiodriver_init(Context *ctx)
 {
     ctx->native_handler = consume_gpio_mailbox;
@@ -49,17 +60,18 @@ static void consume_gpio_mailbox(Context *ctx)
     Message *message = mailbox_dequeue(ctx);
     term msg = message->message;
     term pid = term_get_tuple_element(msg, 0);
-    term cmd = term_get_tuple_element(msg, 1);
+    term req = term_get_tuple_element(msg, 2);
+    term cmd = term_get_tuple_element(req, 0);
 
     int local_process_id = term_to_local_process_id(pid);
     Context *target = globalcontext_get_process(ctx->global, local_process_id);
 
     if (cmd == SET_LEVEL_ATOM) {
-        term gpio_tuple = term_get_tuple_element(msg, 2);
+        term gpio_tuple = term_get_tuple_element(req, 1);
         term gpio_port_atom = term_get_tuple_element(gpio_tuple, 0);
         uint32_t gpio_port = port_atom_to_gpio_port(ctx, gpio_port_atom);
         int32_t gpio_pin_num = term_to_int32(term_get_tuple_element(gpio_tuple, 1));
-        int32_t level = term_to_int32(term_get_tuple_element(msg, 3));
+        int32_t level = term_to_int32(term_get_tuple_element(req, 2));
 
         if (level != 0) {
             gpio_set(gpio_port, 1 << gpio_pin_num);
@@ -70,11 +82,11 @@ static void consume_gpio_mailbox(Context *ctx)
         ret = OK_ATOM;
 
     } else if (cmd == SET_DIRECTION_ATOM) {
-        term gpio_tuple = term_get_tuple_element(msg, 2);
+        term gpio_tuple = term_get_tuple_element(req, 1);
         term gpio_port_atom = term_get_tuple_element(gpio_tuple, 0);
         uint32_t gpio_port = port_atom_to_gpio_port(ctx, gpio_port_atom);
         int32_t gpio_pin_num = term_to_int32(term_get_tuple_element(gpio_tuple, 1));
-        term direction = term_get_tuple_element(msg, 3);
+        term direction = term_get_tuple_element(req, 2);
 
         uint16_t rcc_port = gpio_port_to_rcc_port(gpio_port);
         // Set direction implicitly enables the port of the GPIO
@@ -100,9 +112,16 @@ static void consume_gpio_mailbox(Context *ctx)
         ret = ERROR_ATOM;
     }
 
-    free(message);
+    term ret_msg;
+    if (UNLIKELY(memory_ensure_free(ctx, 3) != MEMORY_GC_OK)) {
+        ret_msg = OUT_OF_MEMORY_ATOM;
+    } else {
+        term ref = term_get_tuple_element(msg, 1);
+        ret_msg = create_pair(ctx, ref, ret);
+    }
 
-    mailbox_send(target, ret);
+    mailbox_send(target, ret_msg);
+    mailbox_destroy_message(message);
 }
 
 static uint32_t port_atom_to_gpio_port(Context *ctx, term port_atom)