A121163 Lab4

lab3/kernel/src/exception.c

@@ -24,13 +24,13 @@ void el1h_irq_router(){
         if (*AUX_MU_IIR_REG & (1 << 1)) // FIFO clear bits
         {
             *AUX_MU_IER_REG &= ~(2);  // disable write interrupt
-            irqtask_add(uart_w_irq_handler, UART_IRQ_PRIORITY);
+            irqtask_add(uart_w_irq_handler, UART_IRQ_PRIORITY); //rpi write mean we read
             irqtask_run_preemptive(); // run the queued task before returning to the program.
         }
         else if (*AUX_MU_IIR_REG & (2 << 1)) // Interrupt ID bits
         {
             *AUX_MU_IER_REG &= ~(1);  // disable read interrupt
-            irqtask_add(uart_r_irq_handler, timer_priority);
+            irqtask_add(uart_r_irq_handler, UART_IRQ_PRIORITY); //rpi read mean we write
             irqtask_run_preemptive();
         }
     }
@@ -154,8 +154,7 @@ void irqtask_run_preemptive()
         // Run new task (early return) if its priority is lower than the scheduled task.
         if (curr_task_priority <= the_task->priority)
         {
-            exit = 1;
-
+            //exit = 1;
             el1_interrupt_enable();
             break;
         }

lab3/kernel/src/shell.c

@@ -33,12 +33,12 @@ void cli_cmd_read(char* buffer)
     while (1)
     {
         if (idx >= CMD_MAX_LEN) break;
-        c = uart_async_getc(); //test preemtive
+        c = uart_async_getc(); 
         if (c == '\n') break;
 
         if (c == 127 && idx > 0)
         {
-            uart_puts("\b \b"); //test preemptive
+            uart_puts("\b \b"); 
             idx--;
             continue;
         }        
@@ -301,7 +301,7 @@ void do_cmd_reboot()
 void do_test_preemptive()
 {
     add_timer(test_loop, 1, "test loop");
-    add_timer(set_exit, 10, "exit");
+    add_timer(set_exit, 5, "exit");
 }
 
 volatile int exit = 0;
@@ -314,6 +314,6 @@ void test_loop()
 
 void set_exit()
 {
-    //exit = 1;
-    uart_sendline("We set exit as 1 to exit infinite loop at t = 10s.\n");
+    exit = 1;
+    uart_sendline("We set exit as 1 to exit infinite loop at t = 5s.\n");
 }

lab3/kernel/src/timer.c

@@ -7,6 +7,7 @@
 #define STR(x) #x
 #define XSTR(s) STR(s)
 
+
 struct list_head* timer_event_list;  // first head has nothing, store timer_event_t after it 
 
 void timer_list_init(){
@@ -60,12 +61,13 @@ void timer_event_callback(timer_event_t * timer_event){
     }
     core_timer_enable();
     ((void (*)(char*))timer_event->callback)(timer_event->args);  // call the event
+
 }
 
 void timer_set2sAlert(char* str)
 {
     static int count = 0;
-    if(count > 10){
+    if(count > 3){
         return;
     }
     count++;

lab3/kernel/src/uart1.c

@@ -90,32 +90,53 @@ int  uart_sendline(char* fmt, ...) {
 }
 
 
-// uart_async_getc read from buffer
-// uart_r_irq_handler write to buffer then output
+// Read a character asynchronously from UART receive buffer.
 char uart_async_getc() {
-    *AUX_MU_IER_REG |=1; // enable read interrupt
-    // do while if buffer empty
-    while (uart_rx_buffer_ridx == uart_rx_buffer_widx) *AUX_MU_IER_REG |=1; // enable read interrupt
+    // Enable read interrupt
+    *AUX_MU_IER_REG |= 1;
+
+    // Loop until the buffer has data
+    while (uart_rx_buffer_ridx == uart_rx_buffer_widx) {
+        *AUX_MU_IER_REG |= 1; // Keep enabling read interrupt
+    }
+
+    // Disable interrupts to ensure atomic operations
     el1_interrupt_disable();
+
+    // Read character from the buffer and increment read index
     char r = uart_rx_buffer[uart_rx_buffer_ridx++];
+    // Wrap around the index if it exceeds the buffer size
     if (uart_rx_buffer_ridx >= VSPRINT_MAX_BUF_SIZE) uart_rx_buffer_ridx = 0;
+
+    // Re-enable interrupts
     el1_interrupt_enable();
-    return r;
+
+    return r; // Return the read character
 }
 
-
-// uart_async_putc writes to buffer
-// uart_w_irq_handler read from buffer then output
+// Write a character asynchronously to UART transmit buffer.
 void uart_async_putc(char c) {
-    // if buffer full, wait for uart_w_irq_handler
-    while( (uart_tx_buffer_widx + 1) % VSPRINT_MAX_BUF_SIZE == uart_tx_buffer_ridx )  *AUX_MU_IER_REG |=2;  // enable write interrupt
+    // Wait if the buffer is full
+    while((uart_tx_buffer_widx + 1) % VSPRINT_MAX_BUF_SIZE == uart_tx_buffer_ridx) {
+        *AUX_MU_IER_REG |= 2;  // Enable write interrupt
+    }
+
+    // Disable interrupts to ensure atomic operations
     el1_interrupt_disable();
+
+    // Write character to the buffer and increment write index
     uart_tx_buffer[uart_tx_buffer_widx++] = c;
-    if(uart_tx_buffer_widx >= VSPRINT_MAX_BUF_SIZE) uart_tx_buffer_widx=0;  // cycle pointer
+    // Wrap around the index if it exceeds the buffer size
+    if(uart_tx_buffer_widx >= VSPRINT_MAX_BUF_SIZE) uart_tx_buffer_widx = 0;
+
+    // Re-enable interrupts
     el1_interrupt_enable();
-    *AUX_MU_IER_REG |=2;  // enable write interrupt
+
+    // Enable write interrupt
+    *AUX_MU_IER_REG |= 2;
 }
 
+
 int  uart_puts(char* fmt, ...) {
     __builtin_va_list args;
     __builtin_va_start(args, fmt);
@@ -147,25 +168,36 @@ void uart_interrupt_disable(){
 }
 
 
-void uart_r_irq_handler(){
-    if((uart_rx_buffer_widx + 1) % VSPRINT_MAX_BUF_SIZE == uart_rx_buffer_ridx)
-    {
-        *AUX_MU_IER_REG &= ~(1);  // disable read interrupt
+// UART receive interrupt handler
+void uart_r_irq_handler() {
+    // Check if the buffer is full
+    if((uart_rx_buffer_widx + 1) % VSPRINT_MAX_BUF_SIZE == uart_rx_buffer_ridx) {
+        // Disable read interrupt to prevent overflow
+        *AUX_MU_IER_REG &= ~(1);
         return;
     }
+    // Read data from UART and store it in the buffer
     uart_rx_buffer[uart_rx_buffer_widx++] = uart_recv();
-    if(uart_rx_buffer_widx>=VSPRINT_MAX_BUF_SIZE) uart_rx_buffer_widx=0;
-    *AUX_MU_IER_REG |=1;
+    // Wrap the write index if it reaches the buffer size
+    if(uart_rx_buffer_widx >= VSPRINT_MAX_BUF_SIZE) uart_rx_buffer_widx = 0;
+    // Re-enable read interrupt
+    *AUX_MU_IER_REG |= 1;
 }
 
-void uart_w_irq_handler(){
-    if(uart_tx_buffer_ridx == uart_tx_buffer_widx)
-    {
-        *AUX_MU_IER_REG &= ~(2);  // disable write interrupt
-        return;  // buffer empty
+// UART write interrupt handler
+void uart_w_irq_handler() {
+    // Check if the buffer is empty
+    if(uart_tx_buffer_ridx == uart_tx_buffer_widx) {
+        // Disable write interrupt to avoid unnecessary interrupts
+        *AUX_MU_IER_REG &= ~(2);
+        return;  // Exit if nothing to send
     }
+    // Send data from the buffer via UART
     uart_send(uart_tx_buffer[uart_tx_buffer_ridx++]);
-    if(uart_tx_buffer_ridx>=VSPRINT_MAX_BUF_SIZE) uart_tx_buffer_ridx=0;
-    *AUX_MU_IER_REG |=2;  // enable write interrupt
+    // Wrap the read index if it reaches the buffer size
+    if(uart_tx_buffer_ridx >= VSPRINT_MAX_BUF_SIZE) uart_tx_buffer_ridx = 0;
+    // Re-enable write interrupt
+    *AUX_MU_IER_REG |= 2;
 }
 
+

lab4/bootloader/config.txt

@@ -0,0 +1,3 @@
+kernel=bootloader.img
+arm_64bit=1
+initramfs initramfs.cpio 0x8000000

lab4/bootloader/include/bcm2837/rpi_base.h

@@ -0,0 +1,6 @@
+#ifndef	_RPI_BASE_H_
+#define	_RPI_BASE_H_
+
+#define PERIPHERAL_BASE 0x3F000000
+
+#endif  /*_RPI_BASE_H_ */

lab4/bootloader/include/bcm2837/rpi_gpio.h

@@ -0,0 +1,25 @@
+#ifndef _RPI_GPIO_H_
+#define _RPI_GPIO_H_
+
+#include "bcm2837/rpi_base.h"
+
+#define GPFSEL0         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200000))
+#define GPFSEL1         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200004))
+#define GPFSEL2         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200008))
+#define GPFSEL3         ((volatile unsigned int*)(PERIPHERAL_BASE+0x0020000C))
+#define GPFSEL4         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200010))
+#define GPFSEL5         ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200014))
+#define GPSET0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x0020001C))
+#define GPSET1          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200020))
+#define GPCLR0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200028))
+#define GPLEV0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200034))
+#define GPLEV1          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200038))
+#define GPEDS0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200040))
+#define GPEDS1          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200044))
+#define GPHEN0          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200064))
+#define GPHEN1          ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200068))
+#define GPPUD           ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200094))
+#define GPPUDCLK0       ((volatile unsigned int*)(PERIPHERAL_BASE+0x00200098))
+#define GPPUDCLK1       ((volatile unsigned int*)(PERIPHERAL_BASE+0x0020009C))
+
+#endif /*_RPI_GPIO_H_*/

lab4/bootloader/include/bcm2837/rpi_uart1.h

@@ -0,0 +1,19 @@
+#ifndef	_RPI_UART1_H_
+#define	_RPI_UART1_H_
+
+#include "bcm2837/rpi_base.h"
+
+#define AUX_ENABLES     ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215004))
+#define AUX_MU_IO_REG   ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215040))
+#define AUX_MU_IER_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215044))
+#define AUX_MU_IIR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215048))
+#define AUX_MU_LCR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x0021504C))
+#define AUX_MU_MCR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215050))
+#define AUX_MU_LSR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215054))
+#define AUX_MU_MSR_REG  ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215058))
+#define AUX_MU_SCRATCH  ((volatile unsigned int*)(PERIPHERAL_BASE+0x0021505C))
+#define AUX_MU_CNTL_REG ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215060))
+#define AUX_MU_STAT_REG ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215064))
+#define AUX_MU_BAUD_REG ((volatile unsigned int*)(PERIPHERAL_BASE+0x00215068))
+
+#endif  /*_RPI_UART1_H_ */

lab4/bootloader/include/power.h

@@ -0,0 +1,8 @@
+#ifndef	_POWER_H_
+#define	_POWER_H_
+
+#define PM_PASSWORD 0x5a000000
+#define PM_RSTC     0x3F10001c
+#define PM_WDOG     0x3F100024
+
+#endif /*_POWER_H_*/

lab4/bootloader/include/shell.h

@@ -0,0 +1,23 @@
+#ifndef _SHELL_H_
+#define _SHELL_H_
+
+#define CLI_MAX_CMD 3
+#define CMD_MAX_LEN 32
+#define MSG_MAX_LEN 128
+
+typedef struct CLI_CMDS
+{
+    char command[CMD_MAX_LEN];
+    char help[MSG_MAX_LEN];
+} CLI_CMDS;
+
+void cli_cmd_clear(char*, int);
+void cli_cmd_read(char*);
+void cli_cmd_exec(char*);
+void cli_print_banner();
+
+void do_cmd_help();
+void do_cmd_loadimg();
+void do_cmd_reboot();
+
+#endif /* _SHELL_H_ */

lab4/bootloader/include/uart1.h

@@ -0,0 +1,11 @@
+#ifndef	_UART1_H_
+#define	_UART1_H_
+
+void uart_init();
+char uart_getc();
+char uart_recv();
+void uart_send(unsigned int c);
+int  uart_puts(char* fmt, ...);
+void uart_2hex(unsigned int d);
+
+#endif /*_UART1_H_*/

lab4/bootloader/include/utils.h

@@ -0,0 +1,11 @@
+#ifndef _UTILS_H_
+#define _UTILS_H_
+
+#define VSPRINT_MAX_BUF_SIZE 128
+
+unsigned int sprintf(char *dst, char* fmt, ...);
+unsigned int vsprintf(char *dst,char* fmt, __builtin_va_list args);
+
+int  strcmp(const char*, const char*);
+
+#endif /* _UTILS_H_ */

lab4/bootloader/makefile

@@ -0,0 +1,42 @@
+ARMGNU ?= aarch64-linux-gnu
+
+CFLAGS = -Wall -nostdlib -nostartfiles -ffreestanding -Iinclude -mgeneral-regs-only
+ASMFLAGS = -Iinclude
+
+BUILD_DIR = build
+SRC_DIR = src
+#---------------------------------------------------------------------------------------
+
+C_FILES = $(wildcard $(SRC_DIR)/*.c)
+ASM_FILES = $(wildcard $(SRC_DIR)/*.S)
+OBJ_FILES = $(C_FILES:$(SRC_DIR)/%.c=$(BUILD_DIR)/%_c.o)
+OBJ_FILES += $(ASM_FILES:$(SRC_DIR)/%.S=$(BUILD_DIR)/%_s.o)
+
+DEP_FILES = $(OBJ_FILES:%.o=%.d)
+-include $(DEP_FILES)
+
+$(BUILD_DIR)/%_c.o: $(SRC_DIR)/%.c
+	@mkdir -p $(@D)
+	$(ARMGNU)-gcc $(CFLAGS) -MMD -c $< -o $@
+
+$(BUILD_DIR)/%_s.o: $(SRC_DIR)/%.S
+	$(ARMGNU)-gcc $(ASMFLAGS) -MMD -c $< -o $@
+
+bootloader.img: $(SRC_DIR)/link.ld $(OBJ_FILES)
+	$(ARMGNU)-ld -T $(SRC_DIR)/link.ld -o $(BUILD_DIR)/bootloader.elf  $(OBJ_FILES)
+	$(ARMGNU)-objcopy $(BUILD_DIR)/bootloader.elf -O binary bootloader.img
+
+all: bootloader.img
+
+clean:
+	rm -rf $(BUILD_DIR) *.img
+
+run_std:
+	qemu-system-aarch64 -M raspi3b -kernel bootloader.img -serial null -serial stdio -initrd initramfs.cpio -dtb bcm2710-rpi-3-b-plus.dtb
+
+run_pty:
+	qemu-system-aarch64 -M raspi3b -kernel bootloader.img -serial null -serial pty -initrd initramfs.cpio -dtb bcm2710-rpi-3-b-plus.dtb
+
+debug:
+	qemu-system-aarch64 -M raspi3b -kernel bootloader.img -display none -S -s
+