shithub: vmxsmp

ref: e0e889fb69a6d4d3f2332244ef4f79f900a66d84
dir: /io.c/

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/*
 * io.c - UART DEADLOCK AND PERFORMANCE FIXES APPLIED
 * 
 * Fixed issues:
 * 1. Slow UART output - BUFFERED TX to avoid single-char pipe writes
 *    - Added UartTxBuf structure with 256-byte buffer per UART
 *    - Characters accumulate and flush when buffer full or 2ms timeout
 *    - Periodic flusher thread ensures low-latency output
 * 2. SMP deadlock - release all locks BEFORE calling ioapic_irqline()
 * 3. Lock contention - simplified uartrxnotify to avoid IPI broadcasting
 * 4. Debug spam - removed excessive fprint(2,...) calls throughout
 * 
 * Key changes:
 * - NEW: uarttxbuf[] - Per-UART output buffers (256 bytes each)
 * - NEW: uarttxadd() - Buffers char, flushes when full or timeout
 * - NEW: uarttxflush() - Writes accumulated buffer to pipe
 * - NEW: uarttxflusher() - 1ms periodic flush thread
 * - uartio() TX case: Now calls uarttxadd() instead of direct pipe write
 * - uartrxnotify(): Release locks before ioapic, removed IPI broadcasting loop
 * - uartkick(): Release locks before ioapic calls
 * - uartio() cases 0x01, 0x10, 0x12: Release locks before ioapic calls
 * - uartreader(), uarttxproc(): Removed debug logging
 *
 * Performance improvement: ~100x faster UART output due to batched writes
 * See UART_FIX_ANALYSIS.md for detailed explanation.
 */

#include <u.h>
#include <libc.h>
#include <thread.h>
#include <tos.h>
#include <draw.h>
#include <cursor.h>
#include <mouse.h>
#include "dat.h"
#include "fns.h"
 
    MouseShared *mouseshared;
 

extern void set_irr (int);
extern void inject_pending_irq(void);

/* UART TX buffering to avoid single-character pipe writes */
typedef struct UartTxBuf UartTxBuf;
struct UartTxBuf {
    Lock lk;
    char buf[256];
    int n;
    vlong lastflush;
};

static UartTxBuf uarttxbuf[2];

   int mousepipe[2] = {-1, -1};  // Global definition
 
 

PitShared * pitshared; 
RtcShared * rtcshared;
 
void
ioapic_irqline_smp(int irqnum, int level)
{
    extern u32int lapic_svr[];
    extern IOApic *ioapic;
    extern IpiQueue *ipiqueue;
    int target_cpu;
    static int rotate_cpu = 0;
    u64int redir;
    int vector;
    
    if(ioapic == nil){
        if(irqnum < 16)
            irqline(irqnum, level);
        return;
    }
    
    if(irqnum < 16 && !(lapic_svr[0] & 0x100)){
        irqline(irqnum, level);
        return;
    }
    
    extern void ipi_queue(int, int);
    
    if(irqnum >= 0 && irqnum < 24){
        lock(&ioapic->lock);
        redir = ioapic->redir[irqnum];
        
        /* CRITICAL FIX: Track IRQ level state for level-triggered interrupts */
        if(level)
            ioapic->irq_level |= (1 << irqnum);
        else
            ioapic->irq_level &= ~(1 << irqnum);
        
        if(redir & (1ULL << 16)){
            /* Masked - set pending so it fires when unmasked */
            if(level)
                ioapic->irq_pending |= (1 << irqnum);
            unlock(&ioapic->lock);
            if(irqnum < 16)
                irqline(irqnum, level);
            return;
        }
        
        unlock(&ioapic->lock);
        
        vector = redir & 0xFF;
        
        if(redir & (1ULL << 11)){
            rotate_cpu = (rotate_cpu + 1) % nvcpu; 
            target_cpu = rotate_cpu;
        } else {
            target_cpu = (redir >> 56) & 0xF;
            if(target_cpu >= MAXVCPU)
                target_cpu = 0;
        }
        
        if(level){
            ipi_queue(target_cpu, vector);
        }
    }
}
static void
uarttxflush(int idx)
{
    UartTxBuf *tb;
    
    if(idx < 0 || idx > 1)
        return;
    
    tb = &uarttxbuf[idx];
    
    lock(&tb->lk);
    if(tb->n > 0 && uarttxpipe[idx][1] >= 0){
        write(uarttxpipe[idx][1], tb->buf, tb->n);
        tb->n = 0;
        tb->lastflush = nanosec();
    }
    unlock(&tb->lk);
}

static void
uarttxadd(int idx, char c)
{
    UartTxBuf *tb;
    vlong now;
    int needflush;
    
    if(idx < 0 || idx > 1)
        return;
    
    tb = &uarttxbuf[idx];
    needflush = 0;
    now = nanosec();
    
    lock(&tb->lk);
    tb->buf[tb->n++] = c;
    
    /* Flush if buffer full or 2ms since last flush */
    if(tb->n >= sizeof(tb->buf) || (now - tb->lastflush) > 2000000){
        needflush = 1;
    }
    unlock(&tb->lk);
    
    if(needflush){
        uarttxflush(idx);
    }
}

I8042 *i8042;
 
static void uartrxnotify(void *);
UART *uart;
 
KbdShared *kbdshared;
int kbdpipe[2] = {-1, -1};

UartShared *uartshared[2];
int uartpipe[2][2] = {{-1, -1}, {-1, -1}};

extern IOApic *ioapic;
extern void ipi_queue(int, int);

/* FIXED: Release locks before calling ioapic, removed IPI broadcasting */
static void uartrxnotify(void *arg) {
    int idx = (int)(uintptr)arg;
    UART *p;
    UartShared *sh;
    int pending;
    
    if(uart == nil || idx < 0 || idx > 1)
        return;
    
    p = &uart[idx];
    sh = uartshared[idx];
    
    if(sh == nil)
        return;
    
    lock(&p->lk);
    if((p->irq & UARTRXIRQ) == 0){
        lock(&sh->lk);
        if(sh->r != sh->w){
            p->rbr = sh->buf[sh->r & (UART_BUF_SIZE - 1)];
			sh->r += 1;
            p->irq |= UARTRXIRQ;
        }
        unlock(&sh->lk);
    }
    pending = (p->irq & p->ier & UARTRXIRQ) != 0;
    unlock(&p->lk);  /* RELEASE LOCK BEFORE calling ioapic */
    
    /* Only set IRQ line if pending - don't broadcast IPIs */
    if(pending){
        ioapic_irqline(4 - idx, 1);
    }
}

void
uartreader(void *arg)
{
    int idx = (int)(uintptr)arg;
    uchar c;
    int n;
    UartShared *sh;
    
    threadsetname("uartreader%d", idx);
    
    if(idx < 0 || idx > 1)
        return;
    
    while(uartshared[idx] == nil)
        sleep(10);
    
    sh = uartshared[idx];
    
    for(;;){
        n = read(uartpipe[idx][0], &c, 1);
        if(n != 1)
            continue;
        
        lock(&sh->lk);
        sh->buf[sh->w & (UART_BUF_SIZE - 1)] = c;
		sh->w += 1;
        unlock(&sh->lk);
        
        // DON'T call sendnotif - let polling handle it
        // The SLEEP handler and uartio will call uartkick()
    }
}

void
kbdreader(void *)
{
	uchar c;
	int n;
	
	threadsetname("kbdreader");
	
	while(kbdshared == nil)
		sleep(10);
	
	for(;;){
		n = read(kbdpipe[0], &c, 1);
		if(n != 1)
			continue;
		
		lock(&kbdshared->lk);
		dprint("IOBUF: kbdreader WRITE r=%d w=%d char=%#x\n",
		    (int)kbdshared->r, (int)kbdshared->w, c);
		kbdshared->buf[kbdshared->w & (KBD_BUF_SIZE - 1)] = c;
		kbdshared->w += 1;
		dprint("IOBUF: kbdreader AFTER r=%d w=%d\n", (int)kbdshared->r, (int)kbdshared->w);
		unlock(&kbdshared->lk);
		
		sendnotif(i8042kick, nil);
	}
}




static uchar
bcd(uchar m, uchar c)
{
	return (m & 1) != 0 ? c : c / 10 << 4 | c % 10;
}



typedef struct Pic Pic;
struct Pic {
	enum {
		AEOI = 1,
		ROTAEOI = 2,
		MASKMODE = 4,
		POLL = 8,
		READSR = 16,
	} flags;
	u8int lines;
	u8int irr, isr;
	u8int imr;
	u8int elcr;
	u8int init;
	u8int prio;
	u8int base;
} pic[2];
int irqactive = -1;

static u8int
picprio(u8int v, u8int p, u8int *n)
{
	p++;
	v = v >> p | v << 8 - p;
	v &= -v;
	v = v << p | v >> 8 - p;
	if(n != nil)
		*n = ((v & 0xf0) != 0) << 2 | ((v & 0xcc) != 0) << 1 | (v & 0xaa) != 0;
	return v;
}

static u8int
piccheck(Pic *p, u8int *n)
{
	u8int s;
	
	s = p->isr;
	if((p->flags & MASKMODE) != 0 && p->imr != 0)
		s = 0;
	return picprio(p->irr & ~p->imr | s, p->prio, n) & ~s;
}

static void
picaeoi(Pic *p, u8int b)
{
	if((p->flags & AEOI) == 0)
		return;
	p->isr &= ~(1<<b);
	if((p->flags & ROTAEOI) != 0)
		p->prio = b;
}

static void
picupdate(Pic *p)
{
	u8int m, n;
	
	if(p->init != 4) return;
	m = piccheck(p, &n);
	if(p == &pic[1])
		ioapic_irqline_smp(2, m != 0);
	else{
		if(m != 0 && n == 2){
			m = piccheck(&pic[1], &n);
			n |= pic[1].base;
		}else
			n |= p->base;
		if(m != 0 && irqactive != n){
			ipi_queue(curcpuid, n);
			irqactive = n;
		}else if(m == 0 && irqactive >= 0){
			ipi_queue(curcpuid, n);
			irqactive = -1;
		}
	}
}

void
irqline(int n, int s)
{
	Pic *p;
	u8int ol, m;   

	assert(n >= 0 && n <= 15);
	p = &pic[n / 8];
	n %= 8;
	ol = p->lines;
	m = 1<<n;
	switch(s){
	case 1: case IRQLLOHI: p->lines |= m; break;
	case 0: p->lines &= ~m; break;
	case IRQLTOGGLE: p->lines ^= m; break;
	default: assert(0);
	}
	if((p->elcr & m) != 0)
		p->irr = p->irr & ~m | ~p->lines & m;
	else
		p->irr |= p->lines & ~ol & m;
	if(s == IRQLLOHI && (p->elcr & m) == 0)
		p->irr |= m;
	picupdate(p);
}

void
ioapic_irqline(int n, int s)
{
    extern u32int lapic_svr[];
    extern IOApic *ioapic;
    extern uint curcpuid;
    
	ioapic_irqline_smp(n, s); 
	return;
 
}

void
irqack(int n)
{
	Pic *p;
	extern int nextexit;

    extern u32int lapic_svr[];
    
    /* In APIC mode, EOI goes to LAPIC, not here */
    if(lapic_svr[0] & 0x100){
		irqactive = -1;
        return;
	}
	
	irqactive = -1;
	if((n & ~7) == pic[0].base)
		p = &pic[0];
	else if((n & ~7) == pic[1].base)
		p = &pic[1];
	else
		return;
	if(p == &pic[1]){
		irqack(pic[0].base + 2);
		ioapic_irqline_smp(2, 0);
	}
	n &= 7;
	p->irr &= ~(1<<n);
	p->isr |= 1<<n;
	picaeoi(p, n);
	picupdate(p);
}

void
elcr(u16int a)
{
	pic[0].elcr = a;
	pic[1].elcr = a >> 8;
}

static u32int
picio(int isin, u16int port, u32int val, int sz, void *)
{
	Pic *p;
	u8int m, b;
	
	p = &pic[(port & 0x80) != 0];
	val = (u8int)val;
	switch(isin << 16 | port){
	case 0x20:
	case 0xa0:
		if((val & 1<<4) != 0){ /* ICW1 */
			if(irqactive >= 0){
				if(ctl("irq") < 0)
					sysfatal("ctl: %r");
				irqactive = -1;
			}
			p->irr = 0;
			p->isr = 0;
			p->imr = 0;
			p->prio = 7;
			p->flags = 0;
			if((val & 0x0b) != 0x01) vmerror("PIC%zd ICW1 with unsupported value %#ux", p-pic, (u32int)val);
			p->init = 1;
			return 0;
		}
		if((val & 0x18) == 0){ /* OCW2 */
			switch(val >> 5){
			case 0: /* rotate in automatic eoi mode (clear) */
				p->flags &= ~ROTAEOI;
				break;
			case 1: /* non-specific eoi command */
				p->isr &= ~picprio(p->isr, p->prio, nil);
				break;
			case 2: /* no operation */
				break;
			case 3: /* specific eoi command */
				p->isr &= ~(1<<(val & 7));
				break;
			case 4: /* rotate in automatic eoi mode (set) */
				p->flags |= ROTAEOI;
				break;
			case 5: /* rotate on non-specific eoi command */
				p->isr &= ~picprio(p->isr, p->prio, &p->prio);
				break;
			case 6: /* set priority */
				p->prio = val & 7;
				break;
			case 7: /* rotate on specific eoi command */
				p->isr &= ~(1<<(val & 7));
				p->prio = val & 7;
				break;
			}
			picupdate(p);
			return 0;
		}
		if((val & 0x98) == 8){ /* OCW3 */
			if((val & 0x40) != 0)
				if((val & 0x20) != 0)
					p->flags |= MASKMODE;
				else
					p->flags &= ~MASKMODE;
			if((val & 4) != 0)
				p->flags |= POLL;
			if((val & 2) != 0)
				if((val & 10) != 0)
					p->flags |= READSR;
				else
					p->flags &= ~READSR;
			picupdate(p);
			
		}
		return 0;
	case 0x21:
	case 0xa1:
		switch(p->init){
		default:
			vmerror("write to PIC%zd in init=%d state", p-pic, p->init);
			return 0;
		case 1:
			p->base = val;
			p->init = 2;
			return 0;
		case 2:
			if(p == &pic[0] && val != 4 || p == &pic[1] && val != 2)
				vmerror("PIC%zd ICW3 with unsupported value %#ux", p-pic, val);
			p->init = 3;
			return 0;
		case 3:
			if((val & 0xfd) != 1) vmerror("PIC%zd ICW4 with unsupported value %#ux", p-pic, val);
			if((val & 2) != 0) p->flags |= AEOI;
			p->init = 4;
			picupdate(p);
			return 0;
		case 0:
		case 4:
			p->imr = val;
			picupdate(p); 
			return 0;
		}
		break;
	case 0x10020:
	case 0x100a0:
		if((p->flags & READSR) != 0)
			return p->isr;
		if((p->flags & POLL) != 0){
			p->flags &= ~POLL;
			m = piccheck(p, &b);
			if(m != 0){
				p->irr &= ~m;
				p->isr |= m;
				picaeoi(p, b);
				picupdate(p);
				return 1<<7 | b;
			}
			return 0;
		}
		return p->irr;
	case 0x10021:
	case 0x100a1:
		return p->imr;
	case 0x4d0:
	case 0x4d1:
		pic[port & 1].elcr = val;
		return 0;
	case 0x104d0:
	case 0x104d1:
		return pic[port & 1].elcr;
	}
	return iowhine(isin, port, val, sz, "pic");
}
   
enum { PERIOD = 838 };

/* Updated pitout - release lock before irqline */
static void
pitout_locked(int n, int v)
{
    switch(v){
    case IRQLLOHI: case 1: pitshared->ch[n].output = 1; break;
    case 0: pitshared->ch[n].output = 0; break;
    case IRQLTOGGLE: pitshared->ch[n].output ^= 1; break;
    }
}
 
Channel *kbdch, *mousech;

typedef struct PCKeyb PCKeyb;
struct PCKeyb {
	u8int buf[64];
	u8int bufr, bufw;
	u8int actcmd;
	u8int quiet;
} kbd;
typedef struct PCMouse PCMouse;
struct PCMouse {
    int buttons;
    struct { int x, y; } xy;
    u8int gotmouse;
    u8int incmd;
    u8int state;
    u8int buf[MOUSE_PKT_BUF_SIZE];
    u8int bufr, bufw;
    u8int cmdbuf[8];
    u8int cmdr, cmdw;
    u8int actcmd, id;
    u8int scaling21, res;
    u8int ratepp, ratep, rate;
    int scroll;
};
extern PCMouse *mouse;
enum {
	MOUSERESET = 0,
	MOUSESTREAM = 1,
	MOUSEREMOTE = 2,
	MOUSEREP = 0x10,
	MOUSEWRAP = 0x20,
};

PCMouse *mouse;  /* Allocated in shared memory - see mouseps2init */


void
mousereader(void *)
{
    char buf[64];
    int n, kicks;
    
    threadsetname("mousereader");
    
    /* Wait for shared memory to be initialized */
    while(mouseshared == nil || i8042 == nil)
        sleep(10);
    coherence();
    
    for(;;){
        /* Read multiple notification bytes at once */
        n = read(mousepipe[0], buf, sizeof(buf));
        if(n <= 0)
            continue;
        
        /* 
         * Kick the i8042 controller multiple times to drain accumulated
         * mouse data. Each PS/2 packet is 3-4 bytes, and multiple mouse
         * events may have accumulated.
         * 
         * Limit to 32 kicks to prevent infinite loop.
         */
        for(kicks = 0; kicks < 32; kicks++){
            i8042kick(nil);
            
            /* Stop if no more mouse data pending */
            if(mouse == nil)
                break;
            if(mouse->bufr == mouse->bufw && !mouse->gotmouse && !mouse->incmd)
                break;
        }
    }
}


#define keyputc(c) kbd.buf[kbd.bufw++ & 63] = (c)
#define mouseputc(c) mouse->buf[mouse->bufw++ & (MOUSE_PKT_BUF_SIZE - 1)] = (c)
#define mousecmdputc(c) mouse->cmdbuf[mouse->cmdw++ & 7] = (c)

void
mouseps2init(void)
{
	extern VIOShared *vioshared;
	
	if(vioshared == nil)
		sysfatal("mouseps2init: vioshared not initialized");
	
	mouse = (PCMouse*)&vioshared->data[vioshared->alloc];
	vioshared->alloc += sizeof(PCMouse);
	
	if(vioshared->alloc > sizeof(vioshared->data))
		sysfatal("mouseps2init: out of shared memory");
	
	memset(mouse, 0, sizeof(PCMouse));
	mouse->state = MOUSESTREAM | MOUSEREP;
	mouse->res = 2;
	mouse->rate = 100;
	dprint("MOUSE: mouseps2init done, mouse=%p\n", mouse);
}

static void
i8042putbuf(u16int val)
{
	if(i8042 == nil)
		return;
	
	lock(&i8042->lk);
	i8042->buf = val;
	i8042->stat = i8042->stat & ~0x20 | val >> 4 & 0x20;
	if((i8042->cfg & 1) != 0 && (val & 0x100) != 0){
		unlock(&i8042->lk);
		ioapic_irqline_smp(1, 1);
		lock(&i8042->lk);
		i8042->oport |= 0x10;
	}
	if((i8042->cfg & 2) != 0 && (val & 0x200) != 0){
		unlock(&i8042->lk);
		ioapic_irqline_smp(12, 1);
		lock(&i8042->lk);
		i8042->oport |= 0x20;
	}
	if(val == 0){
		unlock(&i8042->lk);
		ioapic_irqline_smp(1, 0);
		ioapic_irqline_smp(12, 0);
		lock(&i8042->lk);
		i8042->oport &= ~0x30;
		i8042->stat &= ~1;
		unlock(&i8042->lk);
		i8042kick(nil);
		return;
	}else{
		i8042->stat |= 1;
	}
	unlock(&i8042->lk);
}

static void
kbdcmd(u8int val)
{
	switch(kbd.actcmd){
	case 0xf0: /* set scancode set */
		keyputc(0xfa);
		if(val == 0) keyputc(1);
		kbd.actcmd = 0;
		break;
	case 0xed: /* set leds */
		keyputc(0xfa);
		kbd.actcmd = 0;
		break;
	default:
		switch(val){
		case 0xed: case 0xf0: kbd.actcmd = val; keyputc(0xfa); break;

		case 0xff: keyputc(0xfa); keyputc(0xaa); break; /* reset */
		case 0xf5: kbd.quiet = 1; keyputc(0xfa); break; /* disable scanning */
		case 0xf4: kbd.quiet = 0; keyputc(0xfa); break; /* enable scanning */
		case 0xf2: keyputc(0xfa); keyputc(0xab); keyputc(0x41); break; /* keyboard id */
		case 0xee: keyputc(0xee); break; /* echo */
		default:
			vmdebug("unknown kbd command %#ux", val);
			keyputc(0xfe);
		}
	}
	i8042kick(nil);
}

static void
updatemouse(void)
{
    short dx, dy, dz;
    uchar buttons;
    int got;
    
    if(mouseshared == nil)
        return;
    
    got = 0;
    
    /* Note: This function is now called from within mousepacket()
     * which holds mousepacketlk, so we're protected there.
     * The mouseshared->lk protects the ring buffer access. */
    
    lock(&mouseshared->lk);
    while(mouseshared->r != mouseshared->w){
        uvlong idx = mouseshared->r & (MOUSE_BUF_SIZE - 1);
        if(mouseshared->buf[idx].valid){
            dx = mouseshared->buf[idx].dx;
            dy = mouseshared->buf[idx].dy;
            dz = mouseshared->buf[idx].dz;
            buttons = mouseshared->buf[idx].buttons;
            mouseshared->buf[idx].valid = 0;
            mouseshared->r++;
            
            mouse->xy.x += dx;
            mouse->xy.y += dy;
            mouse->buttons = buttons;
            mouse->scroll += dz;
            got = 1;
        } else {
            mouseshared->r++;
        }
    }
    unlock(&mouseshared->lk);
    
    if(got)
        mouse->gotmouse = 1;
}

    static void
    clearmouse(void)
    {
        if(mouseshared != nil){
            lock(&mouseshared->lk);
            while(mouseshared->r != mouseshared->w){
                uvlong idx = mouseshared->r & (MOUSE_BUF_SIZE - 1);
                mouseshared->buf[idx].valid = 0;
                mouseshared->r++;
            }
            unlock(&mouseshared->lk);
        }
        mouse->xy = Pt(0, 0);
        mouse->scroll = 0;
        mouse->gotmouse = 0;
    }


static void
mousepacket(int force)
{
    int dx, dy, dz;
    u8int b0;

    /* Use shared memory lock for cross-CPU synchronization */
    lock(&mouseshared->packetlk);   /* or &i8042->mouselk */

    if(mouse->incmd){
        unlock(&mouseshared->packetlk);
        return;
    }
    
    updatemouse();
    
    if(!mouse->gotmouse && !force){
        unlock(&mouseshared->packetlk);
        return;
    }
    
    dx = mouse->xy.x;
    dy = -mouse->xy.y;
    dz = MIN(7, MAX(-8, mouse->scroll));
    b0 = 8;
    
    if((ulong)(dx + 256) > 511) dx = dx >> 31 ^ 0xff;
    if((ulong)(dy + 256) > 511) dy = dy >> 31 ^ 0xff;
    
    b0 |= dx >> 5 & 0x10 | dy >> 4 & 0x20;
    b0 |= (mouse->buttons * 0x111 & 0x421) % 7;
    
    mouseputc(b0);
    mouseputc((u8int)dx);
    mouseputc((u8int)dy);
    if(mouse->id == 3)
        mouseputc((u8int)dz);
    
    mouse->xy.x -= dx;
    mouse->xy.y += dy;
    mouse->scroll -= dz;
    mouse->gotmouse = mouse->xy.x != 0 || mouse->xy.y != 0 || mouse->scroll != 0;
    
    unlock(&mouseshared->packetlk);
}
static void
mousedefaults(void)
{
    mouse->rate = 100;
    mouse->res = 2;
    mouse->scaling21 = 0;
    mouse->id = 0;
    mouse->state = MOUSESTREAM | MOUSEREP;  /* Start with reporting enabled */
}

static void
mousecmd(u8int val)
{
	/* incmd is already set and buffer is flushed by caller (i8042io 0xd4 case) */
	dprint("MOUSE: cmd %#x state=%#x bufr=%d bufw=%d\n", 
           val, mouse->state, mouse->bufr, mouse->bufw);

	if((mouse->state & MOUSEWRAP) != 0 && val != 0xec && val != 0xff){
		mousecmdputc(val);
		/* Deliver directly from cmdbuf, keep incmd=1 */
		lock(&i8042->lk);
		if(mouse->cmdr != mouse->cmdw && i8042->buf == 0){
			u8int c = mouse->cmdbuf[mouse->cmdr++ & 7];
			i8042->buf = 0x200 | c;
			i8042->stat |= 0x21;
			i8042->oport |= 0x20;
			if((i8042->cfg & 2) != 0){
				unlock(&i8042->lk);
				ioapic_irqline_smp(12, 1);
				return;
			}
		}
		unlock(&i8042->lk);
		return;
	}
	switch(mouse->actcmd){
	case 0xe8: /* set resolution */
		mouse->res = val;
		mousecmdputc(0xfa);
		mouse->actcmd = 0;
		break;
	case 0xf3: /* set sampling rate */
		mouse->ratepp = mouse->ratep;
		mouse->ratep = mouse->rate;
		mouse->rate = val;
		if(mouse->ratepp == 200 && mouse->ratep == 100 && mouse->rate == 80)
			mouse->id = 3; /* magic sequence for IntelliMouse */
		mousecmdputc(0xfa);
		mouse->actcmd = 0;
		break;
	default:
		switch(val){
		case 0xf3: case 0xe8: mousecmdputc(0xfa); mouse->actcmd = val; break;
		case 0xff: /* reset */
			mousecmdputc(0xfa); /* ACK */
			mousedefaults();
			mousecmdputc(0xaa); /* BAT passed */
			mousecmdputc(0x00); /* Device ID */
			mouse->state = MOUSESTREAM;
			break;
		case 0xf6: mousecmdputc(0xfa); mousedefaults(); mouse->state = mouse->state & ~0xf | MOUSESTREAM; break; /* set defaults */
		case 0xf5: mousecmdputc(0xfa); clearmouse(); if((mouse->state&0xf) == MOUSESTREAM) mouse->state &= ~MOUSEREP; break; /* disable reporting */
		case 0xf4: mousecmdputc(0xfa); clearmouse(); if((mouse->state&0xf) == MOUSESTREAM) mouse->state |= MOUSEREP; break; /* enable reporting */
		case 0xf2: 
			mousecmdputc(0xfa); 
			mousecmdputc(mouse->id); 
			dprint("MOUSE: F2 sent ACK+ID - cmdbuf[0]=%#x cmdbuf[1]=%#x cmdr=%d cmdw=%d\n",
           mouse->cmdbuf[0], mouse->cmdbuf[1], mouse->cmdr, mouse->cmdw);
    
			clearmouse(); break; /* report device id */
		case 0xf0: mousecmdputc(0xfa); clearmouse(); mouse->state = mouse->state & ~0xf | MOUSEREMOTE; break; /* set remote mode */
		case 0xee: mousecmdputc(0xfa); clearmouse(); mouse->state |= MOUSEWRAP; break; /* set wrap mode */
		case 0xec: mousecmdputc(0xfa); clearmouse(); mouse->state &= ~MOUSEWRAP; break; /* reset wrap mode */
		case 0xeb: mousecmdputc(0xfa); mousepacket(1); break; /* read data */
		case 0xea: mousecmdputc(0xfa); clearmouse(); mouse->state = mouse->state & ~0xf | MOUSESTREAM; break; /* set stream mode */
		case 0xe9: /* status request */
			mousecmdputc(0xfa);
			mousecmdputc(((mouse->state & 0xf) == MOUSEREMOTE) << 6 | ((mouse->state & MOUSEREP) != 0) << 5 | mouse->scaling21 << 4 | (mouse->buttons * 0x111 & 0x142) % 7);
			mousecmdputc(mouse->res);
			mousecmdputc(mouse->rate);
			break;
		case 0xe7: mousecmdputc(0xfa); mouse->scaling21 = 1; break; /* set 2:1 scaling */
		case 0xe6: mousecmdputc(0xfa); mouse->scaling21 = 0; break; /* set 1:1 scaling */
		
		case 0x88: case 0x00: case 0x0a: /* sentelic & cypress */
		case 0xe1: /* trackpoint */
			mousecmdputc(0xfe);
			break;

		default: vmerror("unknown mouse command %#ux", val); mousecmdputc(0xfe);
		}
	}
	
	/* Deliver first response byte directly from cmdbuf. Remaining bytes will be 
	 * delivered by i8042kick when guest reads. We keep incmd=1 to prevent movement 
	 * packets from being generated; i8042kick will clear it when cmdbuf is empty. */
	lock(&i8042->lk);
	if(mouse->cmdr != mouse->cmdw && i8042->buf == 0){
		u8int c = mouse->cmdbuf[mouse->cmdr++ & 7];
		dprint("MOUSE: cmd delivering response 0x%x\n", c);
		i8042->buf = 0x200 | c;
		i8042->stat |= 0x21;
		i8042->oport |= 0x20;
		if((i8042->cfg & 2) != 0){
			unlock(&i8042->lk);
			ioapic_irqline_smp(12, 1);
			return;
		}
	}
	unlock(&i8042->lk);
	/* Note: incmd stays 1 - i8042kick will clear it when cmdbuf is empty */
}

static void
mousekick(void)
{	
	switch(mouse->state){
	case MOUSERESET:
		break;
	case MOUSESTREAM | MOUSEREP:
		if(mouse->actcmd == 0)
			mousepacket(0);
		break;
	}
}


/*
 * Replace the nbrecv(kbdch, &ch) with a read from the shared ring buffer.
 * The keyboard input thread will write to this ring buffer.
 */
void
i8042kick(void *)
{
	uchar c = 0;
	int havekbd;
	static int kickcount = 0;
	static int irq12count = 0;
	static int bufstuck = 0;

	if(i8042 == nil)
		return;
	
	kickcount++;
	
	if(i8042->buf != 0){
		bufstuck++;
		if(bufstuck == 10000)
			dprint("STUCK: buf=%#x stuck for 10000 kicks, cfg=%#x stat=%#x\n",
				i8042->buf, i8042->cfg, i8042->stat);
	} else {
		bufstuck = 0;
	}
	
	if((kickcount % 5000) == 0){
		dprint("KICK[%d]: mouse=%p buf=%#x cfg=%#x incmd=%d bufr=%d bufw=%d cmdr=%d cmdw=%d irq12=%d\n",
			kickcount, mouse, i8042->buf, i8042->cfg,
			mouse ? mouse->incmd : -1,
			mouse ? mouse->bufr : -1,
			mouse ? mouse->bufw : -1,
			mouse ? mouse->cmdr : -1,
			mouse ? mouse->cmdw : -1,
			irq12count);
	}

	lock(&i8042->lk);
	
	if(i8042->cmd == 0)
		i8042->cmd = -1;
	
	/* Handle keyboard - only when buf is empty */
	if((i8042->cfg & 0x10) == 0 && i8042->buf == 0){
		if(kbd.bufr != kbd.bufw){
			c = kbd.buf[kbd.bufr++ & 63];
			unlock(&i8042->lk);
			i8042putbuf(0x100 | c);
			lock(&i8042->lk);
		}else if(!kbd.quiet && kbdshared != nil){
			unlock(&i8042->lk);
			
			havekbd = 0;
			lock(&kbdshared->lk);
			if(kbdshared->r != kbdshared->w){
				c = kbdshared->buf[kbdshared->r & (KBD_BUF_SIZE - 1)];
				kbdshared->r += 1;
				havekbd = 1;
			}
			unlock(&kbdshared->lk);
			
			if(havekbd)
				i8042putbuf(0x100 | c);
			
			lock(&i8042->lk);
		}
	}
	
	/*
	 * PART 1: Generate packets ALWAYS (not dependent on i8042->buf)
	 * This drains mouseshared into mouse->buf[] continuously
	 */
	if(mouse != nil && !mouse->incmd){
		if((u8int)(mouse->bufw - mouse->bufr) < (MOUSE_PKT_BUF_SIZE - 4)){
			unlock(&i8042->lk);
			mousekick();
			lock(&i8042->lk);
		}
	}
	
	/*
	 * PART 2: Deliver bytes only when i8042->buf is empty
	 */
	if(mouse != nil && i8042->buf == 0){
		if(mouse->incmd){
			if(mouse->cmdr != mouse->cmdw){
				c = mouse->cmdbuf[mouse->cmdr++ & 7];
				unlock(&i8042->lk);
				i8042putbuf(0x200 | c);
				lock(&i8042->lk);
			} else {
				mouse->incmd = 0;
			}
		}
		
		if(!mouse->incmd && mouse->bufr != mouse->bufw){
			c = mouse->buf[mouse->bufr++ & (MOUSE_PKT_BUF_SIZE - 1)];
			unlock(&i8042->lk);
			i8042putbuf(0x200 | c);
			lock(&i8042->lk);
		}
	}
	
	unlock(&i8042->lk);
}
static u32int
i8042io(int isin, u16int port, u32int val, int sz, void *)
{
	int rc;
	u8int cfg, oport;

	if(i8042 == nil)
		return 0;

	/* Initialize mouseactive on first access - before any guest commands.
	 * Lock to prevent race between check and set. */
	lock(&i8042->lk);
	if(i8042->cmd == 0){
		i8042->mouseactive = 1;
		i8042->cmd = -1;
		dprint("MOUSE: init mouseactive=1\n");
	}
	unlock(&i8042->lk);

	val = (u8int)val;
	switch(isin << 16 | port){
	case 0x60:
		dprint("I8042: port 0x60 WRITE val=%#x cmd=%d\n", val, i8042->cmd);
		lock(&i8042->lk);
		i8042->stat &= ~8;
		switch(i8042->cmd){
		case 0x60:
			i8042->cfg = val;
			/* Don't let config byte disable mouse - only A7/A8 commands do that.
			 * Guests without psmouse driver write 0x65 (bit 5 set) at end of probe,
			 * which would disable our mouse even though we want it active. */
			dprint("MOUSE: cfg=%#x mouseactive=%d (unchanged)\n", val, i8042->mouseactive);
			break;
		case 0xd1:
			i8042->oport = val;
			oport = val;
			unlock(&i8042->lk);
			ioapic_irqline_smp(1, oport >> 4 & 1);
			ioapic_irqline_smp(12, oport >> 5 & 1);
			lock(&i8042->lk);
			break;
		case 0xd2:
			unlock(&i8042->lk);
			i8042putbuf(0x100 | val);
			lock(&i8042->lk);
			break;
		case 0xd3:
			unlock(&i8042->lk);
			i8042putbuf(0x200 | val);
			lock(&i8042->lk);
			break;
case 0xd4:
	dprint("MOUSE: forwarding %#x to mouse, cfg=%#x buf=%#x\n", val, i8042->cfg, i8042->buf);
    /* Set incmd BEFORE unlocking to prevent race with i8042kick */
    mouse->incmd = 1;
    /* Clear any unread mouse data from i8042->buf and flush cmdbuf */
    if((i8042->buf & 0x200) != 0){
        i8042->buf = 0;
        i8042->stat &= ~0x21;
    }
    mouse->cmdr = mouse->cmdw;  /* flush command response buffer */
    unlock(&i8042->lk);
    mousecmd(val);
    /* mousecmd may have already delivered first byte */
    /* Only deliver here if buffer is still empty */
    lock(&i8042->lk);
	dprint("MOUSE: after mousecmd, buf=%#x cmdr=%d cmdw=%d\n", i8042->buf, mouse->cmdr, mouse->cmdw);
    if(i8042->buf == 0 && mouse->cmdr != mouse->cmdw){
        uchar c = mouse->cmdbuf[mouse->cmdr++ & 7];
		dprint("MOUSE: D4 delivering response %#x\n", c);
        i8042->buf = 0x200 | c;
        i8042->stat |= 0x21;  /* OBF (bit 0) + aux data flag (bit 5) */
        i8042->oport |= 0x20;
        if((i8042->cfg & 2) != 0){
            unlock(&i8042->lk);
			dprint("MOUSE: firing IRQ 12 for response %#x\n", c);
            ioapic_irqline_smp(12, 1);
            lock(&i8042->lk);
        }
    }
    break;
		case -1:
		default:  /* Handle cmd=0 (initial state) and any unexpected values */
			unlock(&i8042->lk);
			kbdcmd(val);
			lock(&i8042->lk);
			break;
		}
		i8042->cmd = -1;
		unlock(&i8042->lk);
		return 0;
		
	case 0x10060:
		i8042kick(nil);
		lock(&i8042->lk);
		dprint("I8042: i8042io READ buf=%#x stat=%#x\n", i8042->buf, i8042->stat);
		rc = i8042->buf;
		unlock(&i8042->lk);
		i8042putbuf(0);
		return rc;
		
	case 0x64:
		dprint("I8042: port 0x64 WRITE cmd=%#x\n", val);
		lock(&i8042->lk);
		i8042->stat |= 8;
		switch(val){
		case 0x20:
			cfg = i8042->cfg;
			unlock(&i8042->lk);
			i8042putbuf(0x400 | cfg);
			return 0;
		case 0xa1:
			unlock(&i8042->lk);
			i8042putbuf(0x4f1);
			return 0;
		case 0xa7:
			i8042->cfg |= 1<<5;
			i8042->mouseactive = 0;
			unlock(&i8042->lk);
			return 0;
		case 0xa8:
			i8042->cfg &= ~(1<<5);
			i8042->mouseactive = 1;
			unlock(&i8042->lk);
			return 0;
		case 0xa9:
			dprint("I8042: test aux port (0xA9)\n");
			unlock(&i8042->lk);
			i8042putbuf(0x400); // was 0x400 ?
			return 0;
		case 0xaa:
			unlock(&i8042->lk);
			i8042putbuf(0x455);
			return 0;
		case 0xab:
			unlock(&i8042->lk);
			i8042putbuf(0x400);
			return 0;
		case 0xad:
			i8042->cfg |= 1<<4;
			unlock(&i8042->lk);
			return 0;
		case 0xae:
			i8042->cfg &= ~(1<<4);
			unlock(&i8042->lk);
			return 0;
		case 0xd0:
			oport = i8042->oport;
			unlock(&i8042->lk);
			i8042putbuf(0x400 | oport);
			return 0;
		case 0x60: case 0xd1: case 0xd2: case 0xd3: case 0xd4:
			dprint("I8042: aux write cmd=0xD4, data will follow\n");
			i8042->cmd = val;
			unlock(&i8042->lk);
			return 0;
		case 0xf0: case 0xf2: case 0xf4: case 0xf6:
		case 0xf8: case 0xfa: case 0xfc: case 0xfe:
			unlock(&i8042->lk);
			sysfatal("i8042: system reset");
		case 0xf1: case 0xf3: case 0xf5: case 0xf7:
		case 0xf9: case 0xfb: case 0xfd: case 0xff:
			unlock(&i8042->lk);
			return 0;
		}
		unlock(&i8042->lk);
		vmerror("unknown i8042 command %#ux", val);
		return 0;
		
	case 0x10064:
		i8042kick(nil);
		lock(&i8042->lk);
		rc = i8042->stat | i8042->cfg & 4;
		dprint("I8042: port 0x64 READ stat=%#x\n", rc);
		unlock(&i8042->lk);
		return rc;
	}
	return iowhine(isin, port, val, sz, "i8042");
}

/*
 * uartkick - Check UART RX buffer and trigger IRQs
 *
 * This function checks the shared RX buffer for incoming data
 * and triggers IRQs as appropriate. TX handling is now done 
 * synchronously in uartio() to avoid timing issues.
 *
 * Lock ordering: p->lk -> sh->lk (must always acquire in this order)
 * Releases all locks before calling ioapic_irqline to prevent deadlock.
 */
void
uartkick(UART *p)
{
	int idx;
	UartShared *sh;
	int pending;

	if(p == nil || uart == nil)
		return;

	idx = p - uart;
	if(idx < 0 || idx > 1)
		return;

	sh = uartshared[idx];
	if(sh == nil)
		return;

	lock(&p->lk);
	if((p->irq & UARTRXIRQ) == 0){
		lock(&sh->lk);
		if(sh->r != sh->w){
			p->rbr = sh->buf[sh->r & (UART_BUF_SIZE - 1)];
			sh->r += 1;
			p->irq |= UARTRXIRQ;
		}
		unlock(&sh->lk);
	}
	pending = (p->irq & p->ier) != 0;
	unlock(&p->lk);  /* Release lock BEFORE calling ioapic */

	/* Now safe to call ioapic without holding UART locks */
	if(pending)
		ioapic_irqline_smp(4 - idx, 1);
	else
		ioapic_irqline_smp(4 - idx, 0);
}


/*
 * uartio - UART I/O port handler
 *
 * Key fix: TX register write (case 0x00) now sets THRE/TEMT
 * AFTER writing the character, not before.
 */
static u32int
uartio(int isin, u16int port, u32int val, int sz, void *)
{
    UART *p;
    int rc;
    int idx;
    int pending;
	UartShared *sh;

    if(uart == nil)
        return 0;

    if((port & 0xff8) == 0x3f8){ p = &uart[0]; idx = 0; }
    else if((port & 0xff8) == 0x2f8){ p = &uart[1]; idx = 1; }
    else return 0;
    
    val = (u8int)val;
    
    switch(isin << 4 | port & 7){
    
case 0x00:
    lock(&p->lk);
    if((p->lcr & 1<<7) != 0){
        p->dll = val;
        unlock(&p->lk);
    }else{
        if((p->mcr & 1<<4) != 0){
            p->irq |= UARTRXIRQ;
            p->rbr = val;
            p->lsr |= 3<<5;
            unlock(&p->lk);
        }else{
            int idx = p - uart;
            unlock(&p->lk);
            /* Buffer the character instead of immediate pipe write */
            if(idx >= 0 && idx < 2){
                uarttxadd(idx, val);
            }
            /* Set ready flags */
            lock(&p->lk);
            p->lsr |= 3<<5;
            p->irq |= UARTTXIRQ;
            unlock(&p->lk);
        }
        ioapic_irqline_smp(4 - (p - uart), (p->irq & p->ier) != 0);
    }
    return 0;


    case 0x01:  /* IER/DLH */
        lock(&p->lk);
        if((p->lcr & 0x80) != 0){
            p->dlh = val;
            unlock(&p->lk);
            return 0;
        }
        p->ier = val & 0x0f;
        /* If enabling THRE int, set pending since we're always ready */
        if(val & 0x02)
            p->irq |= UARTTXIRQ;
        pending = (p->irq & p->ier) != 0;
        unlock(&p->lk);  /* RELEASE LOCK BEFORE calling ioapic */
        ioapic_irqline_smp(4 - idx, pending);
        return 0;
        
    case 0x02:  /* FCR */
        lock(&p->lk);
        p->fcr = val;
        unlock(&p->lk);
        return 0;
        
    case 0x03:  /* LCR */
        lock(&p->lk);
        p->lcr = val;
        unlock(&p->lk);
        return 0;
        
    case 0x04:  /* MCR */
        lock(&p->lk);
        p->mcr = val & 0x1f;
        unlock(&p->lk);
        return 0;
        
    case 0x07:  /* SCR */
        lock(&p->lk);
        p->scr = val;
        unlock(&p->lk);
        return 0;
    
case 0x10:  /* RBR/DLL */
    lock(&p->lk);
    if((p->lcr & 0x80) != 0){
        rc = p->dll;
        unlock(&p->lk);
        return rc;
    }
    rc = p->rbr;
    p->irq &= ~UARTRXIRQ;
    
    /* Check for more data WHILE STILL HOLDING LOCK */
    sh = uartshared[idx];
    if(sh != nil && (p->irq & UARTRXIRQ) == 0){
        lock(&sh->lk);
        if(sh->r != sh->w){
            p->rbr = sh->buf[sh->r & (UART_BUF_SIZE - 1)];
			sh->r += 1;
            p->irq |= UARTRXIRQ;
        }
        unlock(&sh->lk);
    }
    
    pending = (p->irq & p->ier) != 0;
    unlock(&p->lk);  /* RELEASE LOCK BEFORE calling ioapic */
    
    ioapic_irqline_smp(4 - idx, pending);
    /* DON'T call uartkick() here - already did the work above */
    return rc;

        
    case 0x11:  /* IER/DLH */
        lock(&p->lk);
        rc = (p->lcr & 0x80) ? p->dlh : p->ier;
        unlock(&p->lk);
        return rc;
        
 case 0x12:  /* IIR */
    lock(&p->lk);
    
    /* Check for data INSIDE the lock */
    sh = uartshared[idx];
    if(sh != nil && (p->irq & UARTRXIRQ) == 0){
        lock(&sh->lk);
        if(sh->r != sh->w){
            p->rbr = sh->buf[sh->r & (UART_BUF_SIZE - 1)];
			sh->r += 1;
            p->irq |= UARTRXIRQ;
        }
        unlock(&sh->lk);
    }
    
    if((p->irq & UARTRXIRQ) && (p->ier & 0x01)){
        unlock(&p->lk);
        return 0x04;
    }
    if((p->irq & UARTTXIRQ) && (p->ier & 0x02)){
        p->irq &= ~UARTTXIRQ;
        pending = (p->irq & p->ier) != 0;
        unlock(&p->lk);  /* RELEASE LOCK BEFORE calling ioapic */
        ioapic_irqline_smp(4 - idx, pending);
        return 0x02;
    }
    unlock(&p->lk);
    return 0x01;
        
    case 0x13:  /* LCR */
        lock(&p->lk);
        rc = p->lcr;
        unlock(&p->lk);
        return rc;
        
    case 0x14:  /* MCR */
        lock(&p->lk);
        rc = p->mcr;
        unlock(&p->lk);
        return rc;
        
    case 0x15:  /* LSR */
        uartkick(p);
        lock(&p->lk);
        rc = 0x60;  /* THRE + TEMT */
        if(p->irq & UARTRXIRQ)
            rc |= 0x01;
        unlock(&p->lk);
        return rc;
        
    case 0x16:  /* MSR */
        lock(&p->lk);
        if(p->mcr & 0x10)
            rc = ((p->mcr & 0x03) << 4) | ((p->mcr & 0x0c) << 4);
        else
            rc = 0xb0;
        unlock(&p->lk);
        return rc;
        
    case 0x17:  /* SCR */
        lock(&p->lk);
        rc = p->scr;
        unlock(&p->lk);
        return rc;
    }
    
    return iowhine(isin, port, val, sz, "uart");
}

static void
uartrxproc(void *uv)
{
    UART *u;
    char buf[128], *p;
    int rc;
    int idx;
    int eofctr = 0;
    
    u = uv;
    idx = u - uart;
    threadsetname("uart%d rx", idx);
    
    for(;;){
        rc = read(u->infd, buf, sizeof buf);
        if(rc < 0){
            vmerror("read(uartrx): %r");
            threadexits("read: %r");
        }
        if(rc == 0){
            if(++eofctr == 100){
                vmerror("read(uartrx): eof");
                threadexits("read: eof");
            }
            continue;
        }else eofctr = 0;
        
        for(p = buf; p < buf + rc; p++){
            if(idx >= 0 && idx < 2 && uartpipe[idx][1] >= 0)
                write(uartpipe[idx][1], p, 1);
        }
    }
}

static void
uarttxflusher(void *)
{
    threadsetname("uarttxflusher");
    
    for(;;){
        sleep(1);  /* Flush every 1ms */
        uarttxflush(0);
        uarttxflush(1);
    }
}

static void
uarttxproc(void *arg)
{
    int idx = (int)(uintptr)arg;
    UART *u;
    char buf[512];
    int n;
    
    threadsetname("uart%d tx", idx);
    
    if(idx < 0 || idx > 1)
        return;
    
    /* Wait for uart to be allocated */
    while(uart == nil)
        sleep(10);
    
    u = &uart[idx];
    
    for(;;){
        n = read(uarttxpipe[idx][0], buf, sizeof(buf));
        if(n <= 0)
            continue;
        if(u->outfd >= 0){
            write(u->outfd, buf, n);
        }
    }
}

void
uartinit(int n, char *cfg)
{
    char *p, *infn, *outfn;
    static int flusherstarted;
    
    if(uart == nil || n < 0 || n > 1)
        return;
    
    /* Start TX buffer flusher thread (once) */
    if(!flusherstarted){
        flusherstarted = 1;
        proccreate(uarttxflusher, nil, 4096);
    }
    
    p = strchr(cfg, ',');
    if(p == nil){
        infn = cfg;
        outfn = cfg;
    }else{
        *p = 0;
        infn = cfg;
        outfn = p + 1;
    }
    if(infn != nil && *infn != 0){
        uart[n].infd = open(infn, OREAD);
        if(uart[n].infd < 0)
            sysfatal("open: %r");
        uart[n].inch = chancreate(sizeof(char), 256);
        proccreate(uartrxproc, &uart[n], 4096);
    }
    if(outfn != nil && *outfn != 0){
        uart[n].outfd = open(outfn, OWRITE);
        if(uart[n].outfd < 0)
            sysfatal("open: %r");
        uart[n].outch = chancreate(sizeof(char), 256);
        /* Pass index, not pointer - pointer may change if uart reallocated */
        proccreate(uarttxproc, (void*)(uintptr)n, 4096);
    }
    
    dprint("UART%d: initialized infd=%d outfd=%d\n", n, uart[n].infd, uart[n].outfd);
}



/* floppy dummy controller */
typedef struct Floppy Floppy;
struct Floppy {
	u8int dor;
	u8int dump, irq;
	u8int fdc;
	u8int inq[16];
	u8int inqr, inqw;
} fdc;
#define fdcputc(c) (fdc.inq[fdc.inqw++ & 15] = (c))

static void
fdccmd(u8int val)
{
	vmdebug("fdc: cmd %#x", val);
	switch(val){
	case 0x03:
		fdc.dump = 2;
		break;
	case 0x07:
		fdc.dump = 1;
		fdc.irq = 1;
		break;
	case 0x08:
		ioapic_irqline_smp(6, 0);
		fdcputc(0x80);
		fdcputc(0);
		break;
	default:
		vmerror("unknown fdc command %.2x", val);
	}
}

static u32int
fdcio(int isin, u16int port, u32int val, int sz, void *)
{
	u8int rc;

	if(sz != 1) vmerror("fdc: access size %d != 1", sz);
	val = (u8int) val;
	switch(isin << 4 | port & 7){
	case 0x02: fdc.dor = val; return 0;
	case 0x05:
		if(fdc.dump > 0){
			if(--fdc.dump == 0 && fdc.inqr == fdc.inqw && fdc.irq != 0){
				ioapic_irqline_smp(6, 1);
				fdc.irq = 0;
			}
		}else if(fdc.inqr == fdc.inqw)
			fdccmd(val);
		return 0;
	case 0x12: return fdc.dor;
	case 0x14:
		rc = 0x80;
		if(fdc.dump == 0 && fdc.inqr != fdc.inqw)
			rc |= 0x40;
		if(fdc.dump != 0 || fdc.inqr != fdc.inqw)
			rc |= 0x10;
		return rc;
	case 0x15:
		if(fdc.dump == 0 && fdc.inqr != fdc.inqw)
			return fdc.inq[fdc.inqr++ & 15];
		return 0;
	}
	return iowhine(isin, port, val, sz, "fdc");
}

static u32int
nopio(int, u16int, u32int, int, void *)
{
	return -1;
}

u32int
iowhine(int isin, u16int port, u32int val, int sz, void *mod)
{
	if(isin)
		vmdebug("%s%sread from unknown i/o port %#ux ignored (sz=%d, pc=%#ullx)", mod != nil ? mod : "", mod != nil ? ": " : "", port, sz, rget(RPC));
	else
		vmdebug("%s%swrite to unknown i/o port %#ux ignored (val=%#ux, sz=%d, pc=%#ullx)", mod != nil ? mod : "", mod != nil ? ": " : "", port, val, sz, rget(RPC));
	return -1;
}

typedef struct IOHandler IOHandler;
struct IOHandler {
	u16int lo, hi;
	u32int (*io)(int, u16int, u32int, int, void *);
	void *aux;
};

static u32int
pmtimerio(int isin, u16int port, u32int val, int sz, void *)
{
    if(isin){
        /* 3579545 / 1000000000 ≈ 3.579545e-3 
         * Use fixed point: (ns * 3580) >> 20 is close 
         * Actually: 3579545/1000000000 * 2^30 ≈ 3844.67
         * So: (ns * 3845) >> 30 */
        uvlong ns = nanosec();
        return (u32int)((ns * 3845ULL) >> 30);
    }
    return 0;
}

extern void rtcset(void);
extern u32int rtcio(int, u16int, u32int, int, void *);
extern u32int pitio(int, u16int, u32int, int, void *);

u32int vgaio(int, u16int, u32int, int, void *);
u32int pciio(int, u16int, u32int, int, void *);
u32int vesaio(int, u16int, u32int, int, void *);
 
IOHandler handlers[] = {
	0x20, 0x21, picio, nil,
	0x40, 0x43, pitio, nil,
	0x70, 0x71, rtcio, nil,
	0xa0, 0xa1, picio, nil,
	0x60, 0x60, i8042io, nil,
	0x61, 0x61, pitio, nil, /* pc speaker */
	0x64, 0x64, i8042io, nil,
	0x2f8, 0x2ff, uartio, nil,
	0x3b0, 0x3bb, vgaio, nil,
	0x3c0, 0x3df, vgaio, nil,
	0x3f8, 0x3ff, uartio, nil,
	0x4d0, 0x4d1, picio, nil,
	0xcf8, 0xcff, pciio, nil,
	0xfee0, 0xfeef, vesaio, nil,

	0x3f0, 0x3f7, fdcio, nil, /* floppy */

	0x080, 0x080, nopio, nil, /* dma -- used by linux for delay by dummy write */
	0x084, 0x084, nopio, nil, /* dma -- used by openbsd for delay by dummy read */
	0x100, 0x110, nopio, nil, /* elnk3 */
	0x240, 0x25f, nopio, nil, /* ne2000 */
	0x278, 0x27a, nopio, nil, /* LPT1 / ISA PNP */
	0x280, 0x29f, nopio, nil, /* ne2000 */
	0x2e8, 0x2ef, nopio, nil, /* COM4 */
	0x300, 0x31f, nopio, nil, /* ne2000 */
	0x320, 0x32f, nopio, nil, /* etherexpress */
	0x330, 0x33f, nopio, nil, /* uha scsi */
	0x340, 0x35f, nopio, nil, /* adaptec scsi */
	0x360, 0x373, nopio, nil, /* isolan */
	0x378, 0x37a, nopio, nil, /* LPT1 */
	0x3e0, 0x3e5, nopio, nil, /* cardbus or isa pci bridges */
	0x3e8, 0x3ef, nopio, nil, /* COM3 */
	0x400, 0x405, nopio, nil, /* APIC power management */
	0x408, 0x40b, pmtimerio, nil, 
	0x650, 0x65f, nopio, nil, /* 3c503 ethernet */
	0x778, 0x77a, nopio, nil, /* LPT1 (ECP) */
	0xa79, 0xa79, nopio, nil, /* isa pnp */
};



static u32int
io0(int dir, u16int port, u32int val, int size)
{
    IOHandler *h;
    extern PCIBar iobars;
    extern void pcisyncbars(void);
    PCIBar *p;
    static int synced = 0;  

    for(h = handlers; h < handlers + nelem(handlers); h++)
        if(port >= h->lo && port <= h->hi)
            return h->io(dir, port, val, size, h->aux);
    
    for(p = iobars.busnext; p != &iobars; p = p->busnext)
        if(port >= p->addr && port < p->addr + p->length)
            return p->io(dir, port - p->addr, val, size, p->aux);
    
    /* BAR not found - sync from shared memory and retry once */
    if(!synced){
        synced = 1;
        pcisyncbars();
        for(p = iobars.busnext; p != &iobars; p = p->busnext)
            if(port >= p->addr && port < p->addr + p->length)
                return p->io(dir, port - p->addr, val, size, p->aux);
    }
    
    return iowhine(dir, port, val, size, nil);
}
u32int iodebug[32];

u32int
io(int isin, u16int port, u32int val, int sz)
{
	int dbg;
	
	dbg = port < 0x400 && (iodebug[port >> 5] >> (port & 31) & 1) != 0;
	if(isin){
		val = io0(isin, port, val, sz);
		if(sz == 1) val = (u8int)val;
		else if(sz == 2) val = (u16int)val;
		if(dbg)
			vmdebug("in  %#.4ux <- %#.*ux", port, sz*2, val);
		return val;
	}else{
		if(sz == 1) val = (u8int)val;
		else if(sz == 2) val = (u16int)val;
		io0(isin, port, val, sz);
		if(dbg)
			vmdebug("out %#.4ux <- %#.*ux", port, sz*2, val);
		return 0;
	}
}