armcm_irq: Move ARM Cortex-M irq handling to new file

The irq handling in sam3x8e isn't specific to the sam3x8e proccessor -
it's generic for all armcm type machines.  So, move the definitions
into a new file generic/armcm-irq.c

Signed-off-by: Kevin O'Connor <kevin@koconnor.net>

src/generic/armcm_irq.c

@@ -0,0 +1,58 @@
+// Definitions for irq enable/disable on ARM Cortex-M processors
+//
+// Copyright (C) 2017  Kevin O'Connor <kevin@koconnor.net>
+//
+// This file may be distributed under the terms of the GNU GPLv3 license.
+
+#include "irq.h" // irqstatus_t
+#include "sched.h" // DECL_SHUTDOWN
+
+void
+irq_disable(void)
+{
+    asm volatile("cpsid i" ::: "memory");
+}
+
+void
+irq_enable(void)
+{
+    asm volatile("cpsie i" ::: "memory");
+}
+
+irqstatus_t
+irq_save(void)
+{
+    irqstatus_t flag;
+    asm volatile("mrs %0, primask" : "=r" (flag) :: "memory");
+    irq_disable();
+    return flag;
+}
+
+void
+irq_restore(irqstatus_t flag)
+{
+    asm volatile("msr primask, %0" :: "r" (flag) : "memory");
+}
+
+// Clear the active irq if a shutdown happened in an irq handler
+static void
+clear_active_irq(void)
+{
+    uint32_t psr;
+    asm volatile("mrs %0, psr" : "=r" (psr));
+    if (!(psr & 0x1ff))
+        // Shutdown did not occur in an irq - nothing to do.
+        return;
+    // Clear active irq status
+    psr = 1<<24; // T-bit
+    uint32_t temp;
+    asm volatile(
+        "  push { %1 }\n"
+        "  adr %0, 1f\n"
+        "  push { %0 }\n"
+        "  push { r0, r1, r2, r3, r12, lr }\n"
+        "  bx %2\n"
+        "1:\n"
+        : "=&r"(temp) : "r"(psr), "r"(0xfffffff9) : "cc");
+}
+DECL_SHUTDOWN(clear_active_irq);

src/sam3x8e/Makefile

@@ -15,7 +15,8 @@ LDFLAGS-y += -T lib/cmsis-sam3x8e/source/gcc/sam3x8e_flash.ld
 LDFLAGS-y += --specs=nano.specs --specs=nosys.specs
 
 # Add source files
-src-y += sam3x8e/main.c sam3x8e/timer.c sam3x8e/gpio.c generic/crc16_ccitt.c
+src-y += sam3x8e/main.c sam3x8e/timer.c sam3x8e/gpio.c
+src-y += generic/crc16_ccitt.c generic/armcm_irq.c
 src-y += ../lib/cmsis-sam3x8e/source/system_sam3xa.c
 src-y += ../lib/cmsis-sam3x8e/source/gcc/startup_sam3xa.c
 src-$(CONFIG_SERIAL) += sam3x8e/serial.c

src/sam3x8e/gpio.c

@@ -6,10 +6,10 @@
 
 #include <stdint.h> // uint32_t
 #include "autoconf.h" // CONFIG_CLOCK_FREQ
+#include "board/irq.h" // irq_save
 #include "command.h" // shutdown
 #include "compiler.h" // ARRAY_SIZE
 #include "gpio.h" // gpio_out_setup
-#include "irq.h" // irq_save
 #include "sam3x8e.h" // Pio
 #include "sched.h" // sched_shutdown
 

src/sam3x8e/irq.h

@@ -1,26 +0,0 @@
-#ifndef __SAM3X8E_IRQ_H
-#define __SAM3X8E_IRQ_H
-// Definitions for irq enable/disable on ARM Cortex-M
-
-static inline void irq_disable(void) {
-    asm volatile("cpsid i" ::: "memory");
-}
-
-static inline void irq_enable(void) {
-    asm volatile("cpsie i" ::: "memory");
-}
-
-typedef unsigned long irqstatus_t;
-
-static inline irqstatus_t irq_save(void) {
-    irqstatus_t flag;
-    asm volatile("mrs %0, primask" : "=r" (flag) :: "memory");
-    irq_disable();
-    return flag;
-}
-
-static inline void irq_restore(irqstatus_t flag) {
-    asm volatile("msr primask, %0" :: "r" (flag) : "memory");
-}
-
-#endif // irq.h

src/sam3x8e/main.c

@@ -4,7 +4,7 @@
 //
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
-#include "board/misc.h" // console_get_input
+#include "board/misc.h" // alloc_maxsize
 #include "sam3x8e.h" // WDT
 #include "sched.h" // sched_main
 
@@ -29,34 +29,6 @@ watchdog_init(void)
 DECL_INIT(watchdog_init);
 
 
-/****************************************************************
- * irq clearing on fault
- ****************************************************************/
-
-// Clear the active irq if a shutdown happened in an irq handler
-static void
-clear_active_irq(void)
-{
-    uint32_t psr;
-    asm volatile("mrs %0, psr" : "=r" (psr));
-    if (!(psr & 0x1ff))
-        // Shutdown did not occur in an irq - nothing to do.
-        return;
-    // Clear active irq status
-    psr = 1<<24; // T-bit
-    uint32_t temp;
-    asm volatile(
-        "  push { %1 }\n"
-        "  adr %0, 1f\n"
-        "  push { %0 }\n"
-        "  push { r0, r1, r2, r3, r12, lr }\n"
-        "  bx %2\n"
-        "1:\n"
-        : "=&r"(temp) : "r"(psr), "r"(0xfffffff9) : "cc");
-}
-DECL_SHUTDOWN(clear_active_irq);
-
-
 /****************************************************************
  * misc functions
  ****************************************************************/

src/sam3x8e/serial.c

@@ -8,11 +8,11 @@
 #include "autoconf.h" // CONFIG_SERIAL_BAUD
 #include "board/gpio.h" // gpio_peripheral
 #include "board/io.h" // readb
+#include "board/irq.h" // irq_save
 #include "board/misc.h" // console_get_input
 #include "command.h" // DECL_CONSTANT
 #include "sam3x8e.h" // UART
 #include "sched.h" // DECL_INIT
-#include "irq.h" // irq_save
 
 #define SERIAL_BUFFER_SIZE 96
 static char receive_buf[SERIAL_BUFFER_SIZE];

src/sam3x8e/timer.c

@@ -5,9 +5,9 @@
 // This file may be distributed under the terms of the GNU GPLv3 license.
 
 #include "autoconf.h" // CONFIG_CLOCK_FREQ
+#include "board/irq.h" // irq_disable
 #include "board/misc.h" // timer_from_us
 #include "command.h" // shutdown
-#include "irq.h" // irq_disable
 #include "sam3x8e.h" // TC0
 #include "sched.h" // sched_timer_kick