Refactored structure, implemented UARTLite and GPIO driver.

Makefile

@@ -1,11 +1,18 @@
 BUILD_DIR = build
 
 C_SOURCES = \
-system_handlers.c \
-system_peripherals.c \
-system_init.c \
-syscalls.c \
-main.c
+src/drivers/xilinx_gpio.c \
+src/drivers/xilinx_uartlite.c \
+src/drivers/xilinx_timer.c \
+src/ibex_it.c \
+src/ibex_system.c \
+src/soc_peripherals.c \
+src/system_init.c \
+src/syscalls.c \
+src/main.c
+
+INCLUDES = \
+-Iinclude
 
 ASM_SOURCES = \
 startup.s
@@ -22,7 +29,7 @@ SZ = /home/imi415/Softwares/Arch/RISC-V/toolchains/rv32imc/bin/riscv32-unknown-e
 HEX = $(CP) -O ihex
 BIN = $(CP) -O binary
 
-CFLAGS += -mabi=ilp32 -march=rv32imc -g
+CFLAGS += -mabi=ilp32 -march=rv32imc -g $(INCLUDES)
 ASFLAGS += -mabi=ilp32 -march=rv32imc -g
 LDFLAGS += -nostartfiles -specs=nano.specs -lc -lm -lnosys
 

include/ibex_system.h

@@ -0,0 +1,7 @@
+#ifndef __IBEX_SYSTEM_H
+#define __IBEX_SYSTEM_H
+
+void __enable_irqs(void);
+void __disable_irqs(void);
+
+#endif

include/main.h

@@ -0,0 +1,9 @@
+#ifndef __MAIN_H
+#define __MAIN_H
+
+#include "soc_peripherals.h"
+
+extern xilinx_uartlite_handle_t soc_uart;
+extern xilinx_gpio_handle_t soc_gpio;
+
+#endif

include/soc_peripherals.h

@@ -0,0 +1,34 @@
+#ifndef __SOC_PERIPHERALS_H
+#define __SOC_PERIPHERALS_H
+
+#include "xilinx_uartlite.h"
+#include "xilinx_gpio.h"
+#include "xilinx_timer.h"
+
+// Peripheral defines
+#define UART0_BASE  0x40010000
+#define GPIO0_BASE  0x40000000
+#define TIMER0_BASE 0x40020000
+
+
+// SoC config
+#define SYS_CLK_FREQ 48000000
+#define SYS_TICK_RATE 1000
+
+// Peripherals
+extern __IO xilinx_uartlite_t *UART0;
+extern __IO xilinx_gpio_t     *GPIO0;
+extern __IO xilinx_timer_t    *TIMER0;
+
+// SysTick
+extern volatile uint32_t SysTick;
+
+static inline uint32_t GetTick() {
+    return SysTick;
+}
+
+static inline uint32_t GetCoreClock() {
+    return SYS_CLK_FREQ;
+}
+
+#endif

include/system_defs.h

@@ -0,0 +1,13 @@
+#ifndef __XILINX_IP_DEFS_H
+#define __XILINX_IP_DEFS_H
+
+#include <stdint.h>
+
+#define __IO volatile
+
+#define RET_OK 0
+#define RET_ERR 1
+
+typedef int sys_ret_t;
+
+#endif

include/xilinx_gpio.h

@@ -0,0 +1,23 @@
+#ifndef __XILINX_GPIO_H
+#define __XILINX_GPIO_H
+
+#include "system_defs.h"
+
+typedef struct {
+    __IO uint32_t DATA;
+    __IO uint32_t TRI;
+    __IO uint32_t DATA2;
+    __IO uint32_t TRI2;
+} xilinx_gpio_t;
+
+typedef struct {
+    __IO xilinx_gpio_t *instance;
+} xilinx_gpio_handle_t;
+
+sys_ret_t xilinx_gpio_init(xilinx_gpio_handle_t *handle);
+sys_ret_t xilinx_gpio_pinmode(xilinx_gpio_handle_t *handle, uint32_t pin, uint8_t output);
+sys_ret_t xilinx_gpio_write(xilinx_gpio_handle_t *handle, uint32_t pin, uint8_t value);
+uint8_t xilinx_gpio_read(xilinx_gpio_handle_t *handle, uint32_t pin);
+sys_ret_t xilinx_gpio_toggle(xilinx_gpio_handle_t *handle, uint32_t pin);
+
+#endif

include/xilinx_timer.h

@@ -0,0 +1,16 @@
+#ifndef __XILINX_TIMER_H
+#define __XILINX_TIMER_H
+
+#include "system_defs.h"
+
+typedef struct {
+    __IO uint32_t TCSR0;
+    __IO uint32_t TLR0;
+    __IO uint32_t TCR0;
+    __IO uint32_t RSVD;
+    __IO uint32_t TCSR1;
+    __IO uint32_t TLR1;
+    __IO uint32_t TCR1;
+} xilinx_timer_t;
+
+#endif

include/xilinx_uartlite.h

@@ -0,0 +1,21 @@
+#ifndef __XILINX_UARTLITE_H
+#define __XILINX_UARTLITE_H
+
+#include "system_defs.h"
+
+typedef struct {
+    __IO uint32_t RX_FIFO;
+    __IO uint32_t TX_FIFO;
+    __IO uint32_t STAT;
+    __IO uint32_t CTRL;
+} xilinx_uartlite_t;
+
+typedef struct {
+    __IO xilinx_uartlite_t *instance;
+} xilinx_uartlite_handle_t;
+
+sys_ret_t xilinx_uartlite_init(xilinx_uartlite_handle_t *handle);
+sys_ret_t xilinx_uartlite_send(xilinx_uartlite_handle_t *handle, uint8_t *data, uint32_t len);
+sys_ret_t xilinx_uartlite_receive(xilinx_uartlite_handle_t *handle, uint8_t *data, uint32_t len);
+
+#endif

linker.ld

@@ -64,6 +64,8 @@ SECTIONS
         _bss_start = _sbss;
         *(.bss)
         *(.bss*)
+        *(.sbss)
+        *(.sbss*)
         *(COMMON)
         . = ALIGN(4);
         _ebss = .;
@@ -73,9 +75,10 @@ SECTIONS
     ._heap_stack_space : 
     {
         . = ALIGN(8);
-        PROVIDE(end = .);
-        PROVIDE(_end = .);
+        _heap_start = .;
         . = . + _minimum_heap_size;
+        _heap_end = .;
+        . = ALIGN(8);
         . = . + _minimum_stack_size;
         . = ALIGN(8);
     } >RW_DATA

src/drivers/xilinx_gpio.c

@@ -0,0 +1,35 @@
+#include "xilinx_gpio.h"
+
+sys_ret_t xilinx_gpio_init(xilinx_gpio_handle_t *handle) {
+    handle->instance->TRI = 0xFFFFFFFF;
+    return RET_OK;
+}
+
+sys_ret_t xilinx_gpio_pinmode(xilinx_gpio_handle_t *handle, uint32_t pin, uint8_t output) {
+    if(output) {
+        handle->instance->TRI &= ~(1U << pin);
+    }
+    else {
+        handle->instance->TRI |= (1U << pin);
+    }
+    return RET_OK;
+}
+
+sys_ret_t xilinx_gpio_write(xilinx_gpio_handle_t *handle, uint32_t pin, uint8_t value) {
+    if(value) {
+        handle->instance->DATA |= (1U << pin);
+    }
+    else {
+        handle->instance->DATA &= ~(1U << pin);
+    }
+    return RET_OK;
+}
+
+uint8_t xilinx_gpio_read(xilinx_gpio_handle_t *handle, uint32_t pin) {
+    return (handle->instance->DATA & (1U << pin)) ? 1 : 0;
+}
+
+sys_ret_t xilinx_gpio_toggle(xilinx_gpio_handle_t *handle, uint32_t pin) {
+    handle->instance->DATA ^= (1U << pin);
+    return RET_OK;
+}

src/drivers/xilinx_timer.c

@@ -0,0 +1,2 @@
+#include "xilinx_timer.h"
+

src/drivers/xilinx_uartlite.c

@@ -0,0 +1,25 @@
+#include "xilinx_uartlite.h"
+
+sys_ret_t xilinx_uartlite_init(xilinx_uartlite_handle_t *handle) {
+    handle->instance->CTRL |= 0x03; // Reset FIFO
+}
+
+sys_ret_t xilinx_uartlite_send(xilinx_uartlite_handle_t *handle, uint8_t *data, uint32_t len) {
+    for(uint32_t i = 0; i < len; i++) {
+        while(handle->instance->STAT & (1U << 0x03) || !(handle->instance->STAT & (1U << 0x02))) { // Check if TX FIFO is full
+            // TODO: Unless we figure out where systick should be.
+        }
+        handle->instance->TX_FIFO = data[i];
+    }
+    return RET_OK;
+}
+
+sys_ret_t xilinx_uartlite_receive(xilinx_uartlite_handle_t *handle, uint8_t *data, uint32_t len) {
+    for(uint32_t i = 0; i < len; i++) {
+        while(handle->instance->STAT & 0x01U == 0) { // Check if RX FIFO is empty
+            // TODO: Unless we figure out where our systick should be.
+        }
+        data[i] = handle->instance->RX_FIFO & 0xFF;
+    }
+    return RET_OK;
+}

src/ibex_it.c

@@ -1,7 +1,8 @@
 #include <stdint.h>
 #include <stdio.h>
 
-#include "xilinx_ip_defs.h"
+#include "soc_peripherals.h"
+#include "xilinx_timer.h"
 
 void Generic_ExceptionCallback(void) {
     for(;;) {

src/ibex_system.c

@@ -0,0 +1,9 @@
+#include "ibex_system.h"
+
+void __attribute__((naked)) __enable_irqs(void) {
+    asm volatile("csrs mstatus, %0\n" : : "r"(0x8));
+}
+
+void __attribute__((naked)) __disable_irqs(void) {
+    asm volatile("csrc mstatus, %0\n" : : "r"(0x08));
+}

src/main.c

@@ -1,14 +1,16 @@
 #include <stdint.h>
 #include <stdio.h>
 
-#include "xilinx_ip_defs.h"
+
+#include "main.h"
 
 #define DDR_BASE 0x1FC00000
 #define DDR_LENGTH 0x100
 
+xilinx_uartlite_handle_t soc_uart;
+xilinx_gpio_handle_t soc_gpio;
+
 int main(int argc, char *argv[]) {
-    GPIO0->TRI = 0xFFFFFFFD;
-    GPIO0->DATA = 0x00;
     printf("Dumping first 256 bytes of DDR memory...\r\n");
     for(uint32_t i = DDR_BASE; i < DDR_BASE + DDR_LENGTH; i++) {
         printf("%02x ", *(uint8_t *)i);
@@ -31,10 +33,13 @@ int main(int argc, char *argv[]) {
 
     uint32_t previous_tick = GetTick();
 
+    xilinx_gpio_pinmode(&soc_gpio, 1, 1);
+    xilinx_gpio_write(&soc_gpio, 1, 0);
+
     while(1) {
         if(GetTick() - previous_tick >= 500) {
-            previous_tick = SysTick;
-            GPIO0->DATA ^= 0x02;
+            previous_tick = GetTick();
+            xilinx_gpio_toggle(&soc_gpio, 1);
             printf("SysTick: %lu\r\n", GetTick());
         }
     }

src/soc_peripherals.c

@@ -0,0 +1,5 @@
+#include "soc_peripherals.h"
+
+__IO xilinx_uartlite_t *UART0  = (xilinx_uartlite_t *) UART0_BASE;
+__IO xilinx_gpio_t     *GPIO0  = (xilinx_gpio_t *)     GPIO0_BASE;
+__IO xilinx_timer_t    *TIMER0 = (xilinx_timer_t *)    TIMER0_BASE;

src/syscalls.c

@@ -0,0 +1,29 @@
+#include <stdint.h>
+#include <errno.h>
+
+#include "main.h"
+
+extern int _heap_start;
+extern int _heap_end;
+static void *_old_heap = &_heap_start;
+
+int _write(int handle, char *data, int size) {
+    int count;
+    handle = handle;
+    xilinx_uartlite_send(&soc_uart, data, size);
+    return size;
+}
+
+void *_sbrk(int nbytes) {
+    char *_old = _old_heap;
+    if(&_heap_start == &_heap_end) {
+        errno = -ENOMEM;
+        return (void *)-1;
+    }
+    if((_old + nbytes) < (char *)&_heap_end) {
+        _old += nbytes;
+    } else {
+        errno = -ENOMEM;
+        return (void *)-1;
+    }
+}

src/system_init.c

@@ -1,10 +1,15 @@
-#include "xilinx_ip_defs.h"
+#include "xilinx_timer.h"
+
+#include "main.h"
 
 __IO uint32_t SysTick;
 
 void System_Init(void) {
-    // Clear UARTLite FIFOs
-    UART0->CTRL = 0x03;
+    soc_uart.instance = UART0;
+    xilinx_uartlite_init(&soc_uart);
+
+    soc_gpio.instance = GPIO0;
+    xilinx_gpio_init(&soc_gpio);
 
     SysTick = 0;
 

startup.s

@@ -54,7 +54,7 @@ copy_data:
     addi x25, x25, 4
     addi x26, x26, 4
 
-    ble x26, x27, copy_data
+    blt x26, x27, copy_data
 
 copy_data_end:
 
@@ -67,7 +67,7 @@ copy_data_end:
 zero_bss:
     sw x0, 0(x26)
     addi x26, x26, 4
-    ble x26, x27, zero_bss
+    blt x26, x27, zero_bss
 
 zero_bss_end:
     jal x1, System_Init

syscalls.c

@@ -1,20 +0,0 @@
-#include <stdint.h>
-#include "xilinx_ip_defs.h"
-
-
-void _putchar(char ch)
-{
-  while(((UART0->STAT & 0x04) == 0) || UART0->STAT & 0x08) {
-    // Waits for TX FIFO empty.
-  }
-  UART0->TX_FIFO = ch;
-}
-
-int _write(int handle, char *data, int size ) {
-    int count;
-    handle = handle;
-    for( count = 0; count < size; count++) {
-        _putchar(data[count]);
-    }
-    return count;
-}

system_peripherals.c

@@ -1,5 +0,0 @@
-#include "xilinx_ip_defs.h"
-
-__IO UartLite_TypeDef *UART0 = (UartLite_TypeDef *)UART0_BASE;
-__IO GPIO_TypeDef *GPIO0 = (GPIO_TypeDef *)GPIO0_BASE;
-__IO Timer_TypeDef *TIMER0 = (Timer_TypeDef *)TIMER0_BASE;

xilinx_ip_defs.h

@@ -1,53 +0,0 @@
-#ifndef __XILINX_IP_DEFS_H
-#define __XILINX_IP_DEFS_H
-
-#include <stdint.h>
-
-#define __IO volatile
-
-typedef struct {
-    __IO uint32_t RX_FIFO;
-    __IO uint32_t TX_FIFO;
-    __IO uint32_t STAT;
-    __IO uint32_t CTRL;
-} UartLite_TypeDef;
-
-typedef struct {
-    __IO uint32_t DATA;
-    __IO uint32_t TRI;
-    __IO uint32_t DATA2;
-    __IO uint32_t TRI2;
-} GPIO_TypeDef;
-
-typedef struct {
-    __IO uint32_t TCSR0;
-    __IO uint32_t TLR0;
-    __IO uint32_t TCR0;
-    __IO uint32_t RSVD;
-    __IO uint32_t TCSR1;
-    __IO uint32_t TLR1;
-    __IO uint32_t TCR1;
-} Timer_TypeDef;
-
-#define UART0_BASE  0x40010000
-#define GPIO0_BASE  0x40000000
-#define TIMER0_BASE 0x40020000
-
-#define SYS_CLK_FREQ 48000000
-#define SYS_TICK_RATE 1000
-
-extern __IO UartLite_TypeDef *UART0;
-extern __IO GPIO_TypeDef *GPIO0;
-extern __IO Timer_TypeDef *TIMER0;
-
-extern __IO uint32_t SysTick;
-
-static inline uint32_t GetTick() {
-    return SysTick;
-}
-
-static inline uint32_t GetCoreClock() {
-    return SYS_CLK_FREQ;
-}
-
-#endif