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#include "drivers/uart.h"
#include "kernel/riscv.h"
#include "kernel/spinlock.h"
#include "kernel/proc.h"
#include "kernel/mm.h"
#include "lib/string.h"
namespace Drivers
{
// Circular buffer structure
struct
{
Spinlock lock;
char buf[UART_RX_BUF_SIZE];
uint32 r; // read index
uint32 w; // write index
} uart_rx;
Spinlock uart_tx_lock;
void uart_init()
{
uart_rx.lock.init("uart_rx");
uart_tx_lock.init("uart_tx");
uart_rx.r = 0;
uart_rx.w = 0;
// Disable interrupts and configure
*(volatile uint8 *)(UART0 + IER) = 0x00;
// Enter baud rate setting mode (LCR_DLAB) = 0x80;
*(volatile uint8 *)(UART0 + LCR) = 0x80;
*(volatile uint8 *)(UART0 + 0) = 0x03; // DLL: 38.4K baud
*(volatile uint8 *)(UART0 + 1) = 0x00; // DLM
// Exit baud rate setting, set 8-bit word length, no parity
*(volatile uint8 *)(UART0 + LCR) = 0x03;
// Reset and enable FIFO
*(volatile uint8 *)(UART0 + FCR) = 0x07;
// Enable Receive Data Available Interrupt
*(volatile uint8 *)(UART0 + IER) = 0x01;
}
void uart_putc(char c)
{
uart_tx_lock.acquire();
while ((*(volatile uint8 *)(UART0 + LSR) & LSR_TX_IDLE) == 0)
;
*(volatile uint8 *)(UART0 + THR) = c;
uart_tx_lock.release();
}
void uart_puts(const char *s)
{
while (*s)
uart_putc(*s++);
}
void uart_put_int(int val)
{
char buf[16];
int i = 0;
if (val == 0)
{
uart_puts("0");
return;
}
if (val < 0)
{
uart_puts("-");
val = -val;
}
while (val > 0)
{
buf[i++] = (val % 10) + '0';
val /= 10;
}
while (i > 0)
{
uart_putc(buf[--i]);
}
}
void print_hex(uint64 val)
{
char hex[] = "0123456789ABCDEF";
uart_puts("0x");
for (int i = 60; i >= 0; i -= 4)
{
uart_putc(hex[(val >> i) & 0xF]);
}
}
void uart_intr()
{
uart_rx.lock.acquire();
while (1)
{
if ((*(volatile uint8 *)(UART0 + LSR) & LSR_RX_READY) == 0)
break;
char c = *(volatile uint8 *)(UART0 + RHR);
uart_rx.buf[uart_rx.w % UART_RX_BUF_SIZE] = c;
uart_rx.w++;
ProcManager::wakeup(&uart_rx);
}
uart_rx.lock.release();
}
// Modern console read: Line buffering + Editing Keys + Echo
int console_read(uint64 target, int len)
{
struct Proc *p = myproc();
int target_idx = 0;
uart_rx.lock.acquire();
while (target_idx < len)
{
while (uart_rx.r == uart_rx.w)
{
if (p->xstate != 0)
{
uart_rx.lock.release();
return -1;
}
ProcManager::sleep(&uart_rx, &uart_rx.lock);
}
char c = uart_rx.buf[uart_rx.r % UART_RX_BUF_SIZE];
uart_rx.r++;
uart_rx.lock.release();
// 1. Handle Backspace (127 or \b)
if (c == 127 || c == '\b')
{
if (target_idx > 0)
{
// Erase character from screen: Backspace, Space, Backspace
uart_putc('\b');
uart_putc(' ');
uart_putc('\b');
target_idx--;
}
uart_rx.lock.acquire();
continue;
}
// 2. Handle Ctrl+U (Kill Line)
if (c == 0x15)
{
while (target_idx > 0)
{
uart_putc('\b');
uart_putc(' ');
uart_putc('\b');
target_idx--;
}
uart_rx.lock.acquire();
continue;
}
// 3. Handle Ctrl+L (Clear Screen)
if (c == 0x0C)
{
uart_puts(ANSI_CLEAR);
uart_puts("$ ");
uart_rx.lock.acquire();
continue;
}
// 4. Handle Return (CR -> LF)
if (c == '\r')
{
c = '\n';
}
// Echo back to user
// uart_putc(c);
if (VM::copyout(p->pagetable, target + target_idx, &c, 1) < 0)
{
return -1;
}
target_idx++;
if (c == '\n')
{
return target_idx;
}
uart_rx.lock.acquire();
}
uart_rx.lock.release();
return target_idx;
}
}
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