Add parallel port handling in parallel.c

Implement parallel port support with detection and configuration.

kernel/parallel.h

@@ -0,0 +1,40 @@
+#ifndef PARALLEL_H
+#define PARALLEL_H
+
+#include <stdint.h>
+#include <stdbool.h>
+
+typedef enum {
+    LPT_PORT_NONE = -1,
+    LPT1_PORT = 0,
+    LPT2_PORT = 1,
+    LPT_MAX_PORTS = 2
+} lpt_port_t;
+
+typedef enum {
+    LPT_MODE_COMPAT = 0,   // Standard (SPP)
+    LPT_MODE_BIDIR,        // PS/2 bidirectional
+    LPT_MODE_EPP,          // IEEE 1284 EPP
+    LPT_MODE_ECP           // IEEE 1284 ECP
+} lpt_mode_t;
+
+typedef struct {
+    uint16_t base;         // Base I/O address (e.g., 0x378, 0x278)
+    bool     present;      // Detected
+    lpt_mode_t mode;       // Current mode
+    uint8_t  irq;          // IRQ line (if known/used)
+} lpt_device_t;
+
+extern lpt_device_t lpt_devices[LPT_MAX_PORTS];
+
+void lpt_init_all(void);
+void lpt_set_mode(lpt_port_t port, lpt_mode_t mode);
+
+// Simple polled I/O
+void lpt_write_byte(lpt_port_t port, uint8_t value);
+uint8_t lpt_read_byte(lpt_port_t port);
+
+// IRQ-driven hook (you implement the handler logic)
+void lpt_irq_handler(lpt_port_t port);
+
+#endif

klibc/include/string.h

@@ -3,13 +3,12 @@
 
 #include <stddef.h>
 
-extern int memcmp(const void *s1, const void *s2, size_t n);
-extern void *memmove(void *dst, const void *src, size_t n);
-extern void *memcpy(void *dst, const void *src, size_t n);
-extern void *memset(void *dst, int c, size_t n);
+extern int memcmp(const void* s1, const void* s2, size_t n);
+extern void* memmove(void* dst, const void* src, size_t n);
+extern void* memcpy(void* dst, const void* src, size_t n);
+extern void* memset(void* dst, int c, size_t n);
 
-extern size_t strlen(const char *s);
-extern int strcmp(const char *s1, const char *s2);
-extern char *strncpy(char *dst, const char *src, size_t n);
+extern size_t strlen(const char* s);
+extern int strcmp(const char* s1, const char* s2);
 
 #endif  // CLASSICOS_KLIBC_STRING_H

klibc/src/string.c

@@ -1,8 +1,8 @@
 #include <string.h>
 
-int memcmp(const void *s1, const void *s2, size_t n) {
-    const unsigned char *c1 = s1;
-    const unsigned char *c2 = s2;
+int memcmp(const void* s1, const void* s2, size_t n) {
+    const unsigned char* c1 = s1;
+    const unsigned char* c2 = s2;
     int d = 0;
 
     while (n--) {
@@ -13,9 +13,9 @@ int memcmp(const void *s1, const void *s2, size_t n) {
     return d;
 }
 
-void *memmove(void *dst, const void *src, size_t n) {
-    const char *p = src;
-    char *q = dst;
+void* memmove(void* dst, const void* src, size_t n) {
+    const char* p = src;
+    char* q = dst;
 #if defined(__i386__) || defined(__x86_64__)
     if (q < p) {
         __asm__ volatile("cld; rep; movsb" : "+c"(n), "+S"(p), "+D"(q));
@@ -41,19 +41,19 @@ void *memmove(void *dst, const void *src, size_t n) {
     return dst;
 }
 
-void *memcpy(void *dst, const void *src, size_t n) {
-    const char *p = src;
-    char *q = dst;
+void* memcpy(void* dst, const void* src, size_t n) {
+    const char* p = src;
+    char* q = dst;
 #if defined(__i386__)
     size_t nl = n >> 2;
     __asm__ volatile("cld ; rep ; movsl ; movl %3,%0 ; rep ; movsb"
-                     : "+c"(nl), "+S"(p), "+D"(q)
-                     : "r"(n & 3));
+                    : "+c"(nl), "+S"(p), "+D"(q)
+                    : "r"(n & 3));
 #elif defined(__x86_64__)
     size_t nq = n >> 3;
     __asm__ volatile("cld ; rep ; movsq ; movl %3,%%ecx ; rep ; movsb"
-                     : "+c"(nq), "+S"(p), "+D"(q)
-                     : "r"((uint32_t)(n & 7)));
+                    : "+c"(nq), "+S"(p), "+D"(q)
+                    : "r"((uint32_t)(n & 7)));
 #else
     while (n--) {
         *q++ = *p++;
@@ -63,20 +63,20 @@ void *memcpy(void *dst, const void *src, size_t n) {
     return dst;
 }
 
-void *memset(void *dst, int c, size_t n) {
-    char *q = dst;
+void* memset(void* dst, int c, size_t n) {
+    char* q = dst;
 
 #if defined(__i386__)
     size_t nl = n >> 2;
     __asm__ volatile("cld ; rep ; stosl ; movl %3,%0 ; rep ; stosb"
-                     : "+c"(nl), "+D"(q)
-                     : "a"((unsigned char)c * 0x01010101U), "r"(n & 3));
+                    : "+c"(nl), "+D"(q)
+                    : "a"((unsigned char)c * 0x01010101U), "r"(n & 3));
 #elif defined(__x86_64__)
     size_t nq = n >> 3;
     __asm__ volatile("cld ; rep ; stosq ; movl %3,%%ecx ; rep ; stosb"
-                     : "+c"(nq), "+D"(q)
-                     : "a"((unsigned char)c * 0x0101010101010101U),
-                       "r"((uint32_t)n & 7));
+                    : "+c"(nq), "+D"(q)
+                    : "a"((unsigned char)c * 0x0101010101010101U),
+                      "r"((uint32_t)n & 7));
 #else
     while (n--) {
         *q++ = c;
@@ -86,15 +86,15 @@ void *memset(void *dst, int c, size_t n) {
     return dst;
 }
 
-size_t strlen(const char *s) {
-    const char *ss = s;
+size_t strlen(const char* s) {
+    const char* ss = s;
     while (*ss) ss++;
     return ss - s;
 }
 
-int strcmp(const char *s1, const char *s2) {
-    const unsigned char *c1 = (const unsigned char *)s1;
-    const unsigned char *c2 = (const unsigned char *)s2;
+int strcmp(const char* s1, const char* s2) {
+    const unsigned char* c1 = (const unsigned char*)s1;
+    const unsigned char* c2 = (const unsigned char*)s2;
     unsigned char ch;
     int d = 0;
 
@@ -105,19 +105,3 @@ int strcmp(const char *s1, const char *s2) {
 
     return d;
 }
-
-char *strncpy(char *dst, const char *src, size_t n) {
-    char *q = dst;
-    const char *p = src;
-    char ch;
-
-    while (n) {
-        n--;
-        *q++ = ch = *p++;
-        if (!ch) break;
-    }
-
-    memset(q, 0, n);
-
-    return dst;
-}

parallel.c

@@ -0,0 +1,130 @@
+#include "parallel.h"
+#include "io.h"
+#include "irq.h"
+#include "serial.h"   // or your print/terminal for debug
+
+// Standard PC LPT base addresses
+static const uint16_t lpt_base_addrs[LPT_MAX_PORTS] = {
+    0x378, // LPT1
+    0x278  // LPT2
+};
+
+lpt_device_t lpt_devices[LPT_MAX_PORTS];
+
+// Register offsets
+#define LPT_DATA(base)      (base + 0)
+#define LPT_STATUS(base)    (base + 1)
+#define LPT_CONTROL(base)   (base + 2)
+
+// STATUS bits
+// bit 7: Busy (inverted), 6: Ack, 5: Paper Out, 4: Select, 3: Error
+// CONTROL bits
+// bit 0: Strobe, 1: Auto Linefeed, 2: Init, 3: Select In, 5: Bidirectional (PS/2)
+
+// Simple presence check: write/read control & status
+static bool lpt_detect(uint16_t base) {
+    uint8_t orig_ctrl = inb(LPT_CONTROL(base));
+    outb(LPT_CONTROL(base), orig_ctrl ^ 0x0F);
+    uint8_t new_ctrl = inb(LPT_CONTROL(base));
+    outb(LPT_CONTROL(base), orig_ctrl);
+
+    // If bits changed as expected, port likely exists
+    if (((orig_ctrl ^ new_ctrl) & 0x0F) == 0x0F) {
+        return true;
+    }
+    return false;
+}
+
+static void lpt_configure_bidir(uint16_t base, bool enable) {
+    uint8_t ctrl = inb(LPT_CONTROL(base));
+    if (enable) {
+        ctrl |= (1 << 5);   // Set bidirectional bit (PS/2)
+    } else {
+        ctrl &= ~(1 << 5);
+    }
+    outb(LPT_CONTROL(base), ctrl);
+}
+
+void lpt_set_mode(lpt_port_t port, lpt_mode_t mode) {
+    if (port < 0 || port >= LPT_MAX_PORTS) return;
+    if (!lpt_devices[port].present) return;
+
+    uint16_t base = lpt_devices[port].base;
+
+    switch (mode) {
+        case LPT_MODE_COMPAT:
+            lpt_configure_bidir(base, false);
+            break;
+        case LPT_MODE_BIDIR:
+            lpt_configure_bidir(base, true);
+            break;
+        case LPT_MODE_EPP:
+            // TODO: EPP requires chipset support & config
+            // For now, just enable bidir as a baseline
+            lpt_configure_bidir(base, true);
+            break;
+        case LPT_MODE_ECP:
+            // TODO: ECP requires FIFO, DMA, and ECR register
+            // Stub for future implementation
+            lpt_configure_bidir(base, true);
+            break;
+    }
+
+    lpt_devices[port].mode = mode;
+}
+
+void lpt_write_byte(lpt_port_t port, uint8_t value) {
+    if (port < 0 || port >= LPT_MAX_PORTS) return;
+    if (!lpt_devices[port].present) return;
+
+    uint16_t base = lpt_devices[port].base;
+
+    // Wait until not busy (bit 7 is inverted busy)
+    while (!(inb(LPT_STATUS(base)) & 0x80))
+        ;
+
+    outb(LPT_DATA(base), value);
+
+    // Pulse strobe
+    uint8_t ctrl = inb(LPT_CONTROL(base));
+    outb(LPT_CONTROL(base), ctrl | 0x01);
+    outb(LPT_CONTROL(base), ctrl & ~0x01);
+}
+
+uint8_t lpt_read_byte(lpt_port_t port) {
+    if (port < 0 || port >= LPT_MAX_PORTS) return 0xFF;
+    if (!lpt_devices[port].present) return 0xFF;
+
+    uint16_t base = lpt_devices[port].base;
+
+    // In bidirectional mode, data register is input
+    return inb(LPT_DATA(base));
+}
+
+// IRQ hook: you wire this into your IRQ handler for the LPT IRQ (usually 7 or 5)
+void lpt_irq_handler(lpt_port_t port) {
+    // For now, just a stub. Later:
+    // - read status
+    // - acknowledge interrupt
+    // - wake waiting writer/reader
+    (void)port;
+}
+
+// Initialize all LPT ports
+void lpt_init_all(void) {
+    for (int i = 0; i < LPT_MAX_PORTS; i++) {
+        lpt_devices[i].base = lpt_base_addrs[i];
+        lpt_devices[i].present = lpt_detect(lpt_devices[i].base);
+        lpt_devices[i].mode = LPT_MODE_COMPAT;
+        lpt_devices[i].irq = 0; // You can fill this if you parse BIOS/PCI/ACPI
+
+        if (lpt_devices[i].present) {
+            serial_write("LPT detected at base 0x");
+            // use your print_hex here if you want
+        }
+    }
+
+    // If you want interrupt-driven I/O:
+    // - Map LPT IRQ (usually 7 for LPT1, 5 for LPT2) in your PIC/IRQ layer
+    // - In your IRQ handler, call lpt_irq_handler(port)
+}