Add new GPIO subsystem.

This gpio subsystem keeps track of the GPIO pins which
have been reserved and takes care of the housekeeping
with keeping them running.

This gpio subsystem also knows which alternate functions
belong to which pins, so it can automatically configure
the pins for the alternate functions.

1 files changed, 23 insertions, 16 deletions

diff --git a/02-usart/src/kern/main.c b/02-usart/src/kern/main.c
index 0e0c89c..32166bc 100644
--- a/02-usart/src/kern/main.c
+++ b/02-usart/src/kern/main.c
@@ -10,24 +10,23 @@
 #include "arch/stm32l4xxx/peripherals/irq.h"
 
 #include "kern/dma/dma_manager.h"
+#include "kern/gpio/gpio_manager.h"
+#include "kern/gpio/sysled.h"
 
 #include "kern/delay.h"
 #include "kern/mem.h"
-#include "kern/spin.h"
 #include "kern/string.h"
 
 /** Overrides the default systick irq handler. */
 void on_systick()
 {
   static int is_on = 0;
-
-  __IO gpio_port_t* port_b = enable_gpio(GPIO_PORT_B);
-  gpio_output_pin_t pin3 = set_gpio_pin_output(port_b, PIN_3);
+  gpio_reserved_pin_t sysled = get_sysled();
 
   if (is_on) {
-    pin_off(pin3);
+    set_gpio_pin_low(sysled);
   } else {
-    pin_on(pin3);
+    set_gpio_pin_high(sysled);
   }
 
   is_on = ! is_on;
@@ -35,17 +34,26 @@ void on_systick()
 
 void setup_usart2(uint32_t baud_rate)
 {
-  __IO gpio_port_t* port_a = enable_gpio(GPIO_PORT_A);
   enable_hsi(&RCC, true);
 
+  int ec = 0;
+  gpio_enable_alternate_function(
+      GPIO_ALTERNATE_FUNCTION_USART2_TX, GPIO_PIN_PA2, &ec);
+
+  if (ec) {
+    unhandled_isr(ec & 0xff);
+  }
+
+  gpio_enable_alternate_function(
+      GPIO_ALTERNATE_FUNCTION_USART2_RX, GPIO_PIN_PA15, &ec);
+
+  if (ec) {
+    unhandled_isr(ec & 0xff);
+  }
+
   set_usart2_clock_src(&RCC, USART_CLK_SRC_HSI16);
   set_usart2_clock_enabled(&RCC, USART_CLK_SRC_HSI16);
 
-  set_gpio_pin_mode(port_a, PIN_2, MODE_ALTERNATE);
-  set_gpio_pin_mode(port_a, PIN_15, MODE_ALTERNATE);
-  set_gpio_alternate_function(port_a, PIN_2, AFN_7);
-  set_gpio_alternate_function(port_a, PIN_15, AFN_3);
-
   /* De-assert reset of USART2 */
   regset(RCC.apb1rst1_r, rcc_usart2rst, 0);
 
@@ -96,14 +104,13 @@ int main()
   // regset(USART2.ic_r, usart_tccf, 1);
   // dma_mem2p_initiate_transfer(dma_chan, thing, strlen(thing));
 
-  __IO gpio_port_t* port_b = enable_gpio(GPIO_PORT_B);
-  gpio_output_pin_t pin3 = set_gpio_pin_output(port_b, PIN_3);
-  pin_on(pin3);
+  gpio_reserved_pin_t sysled = get_sysled();
+  set_gpio_pin_high(sysled);
 
   // usart_printf(&USART2, "Start Configuring Countdown!\n");
 
   /* Set the countdown to start from 1,000,0000. */
-  SCB.strv_r = 10000000;
+  SCB.strv_r = 1000000;
 
   /* Enable interrupts. */
   regset(SCB.stcs_r, scb_tickint, 1);