/* 
 * This file is part of the Palacios Virtual Machine Monitor developed
 * by the V3VEE Project with funding from the United States National 
 * Science Foundation and the Department of Energy.  
 *
 * The V3VEE Project is a joint project between Northwestern University
 * and the University of New Mexico.  You can find out more at 
 * http://www.v3vee.org
 *
 * Copyright (c) 2008, Jack Lange <jarusl@cs.northwestern.edu>
 * Copyright (c) 2008, The V3VEE Project <http://www.v3vee.org> 
 * All rights reserved.
 *
 * Author: Jack Lange <jarusl@cs.northwestern.edu>
 *
 * This is free software.  You are permitted to use,
 * redistribute, and modify it as specified in the file "V3VEE_LICENSE".
 */

#include <palacios/vmm.h>
#include <palacios/vmm_dev_mgr.h>
#include <devices/lnx_virtio_pci.h>
#include <palacios/vm_guest_mem.h>

#include <devices/pci.h>



struct console_config {
    uint16_t cols;
    uint16_t rows;
} __attribute__((packed));




#define QUEUE_SIZE 128

/* Host Feature flags */
#define VIRTIO_CONSOLE_F_SIZE 0x1

struct virtio_console_state {
    struct console_config cons_cfg;
    struct virtio_config virtio_cfg;

    struct vm_device * pci_bus;
    struct pci_device * pci_dev;
    
    struct virtio_queue queue[2];

    struct v3_stream * stream;


    struct virtio_queue * cur_queue;

    struct v3_vm_info * vm;

    int io_range_size;

    void * backend_data;
    struct v3_dev_char_ops * ops;
};


struct virtio_console_state * cons_state = NULL;

static int virtio_reset(struct virtio_console_state * virtio) {

    memset(virtio->queue, 0, sizeof(struct virtio_queue) * 2);

    virtio->cur_queue = &(virtio->queue[0]);

    virtio->virtio_cfg.status = 0;
    virtio->virtio_cfg.pci_isr = 0;

    /* Console configuration */
    // virtio->virtio_cfg.host_features = VIRTIO_NOTIFY_HOST;

    // Virtio Console uses two queues
    virtio->queue[0].queue_size = QUEUE_SIZE;
    virtio->queue[1].queue_size = QUEUE_SIZE;


    memset(&(virtio->cons_cfg), 0, sizeof(struct console_config));

    return 0;
}

static int get_desc_count(struct virtio_queue * q, int index) {
    struct vring_desc * tmp_desc = &(q->desc[index]);
    int cnt = 1;
    
    while (tmp_desc->flags & VIRTIO_NEXT_FLAG) {
	tmp_desc = &(q->desc[tmp_desc->next]);
	cnt++;
    }

    return cnt;
}


static int handle_kick(struct guest_info * core, struct virtio_console_state * virtio) {
    struct virtio_queue * q = virtio->cur_queue;

    PrintDebug("VIRTIO CONSOLE KICK: cur_index=%d (mod=%d), avail_index=%d\n", 
	       q->cur_avail_idx, q->cur_avail_idx % QUEUE_SIZE, q->avail->index);

    while (q->cur_avail_idx < q->avail->index) {
	struct vring_desc * tmp_desc = NULL;
	uint16_t desc_idx = q->avail->ring[q->cur_avail_idx % QUEUE_SIZE];
	int desc_cnt = get_desc_count(q, desc_idx);
	int i = 0;
	uint32_t req_len = 0;


	PrintDebug("Descriptor Count=%d, index=%d\n", desc_cnt, q->cur_avail_idx % QUEUE_SIZE);

	for (i = 0; i < desc_cnt; i++) {
	    addr_t page_addr;
	    tmp_desc = &(q->desc[desc_idx]);
	    
	
	    PrintDebug("Console output (ptr=%p) gpa=%p, len=%d, flags=%x, next=%d\n", 
		       tmp_desc, 
		       (void *)(addr_t)(tmp_desc->addr_gpa), tmp_desc->length, 
		       tmp_desc->flags, tmp_desc->next);
	
	    if (v3_gpa_to_hva(core, tmp_desc->addr_gpa, (addr_t *)&(page_addr)) == -1) {
		PrintError("Could not translate block header address\n");
		return -1;
	    }

	    virtio->ops->output((uint8_t *)page_addr, tmp_desc->length, virtio->backend_data);

	    PrintDebug("Guest Console Currently Ignored\n");

	    req_len += tmp_desc->length;
	    desc_idx = tmp_desc->next;
	}

	q->used->ring[q->used->index % QUEUE_SIZE].id = q->avail->ring[q->cur_avail_idx % QUEUE_SIZE];
	q->used->ring[q->used->index % QUEUE_SIZE].length = req_len; // What do we set this to????

	q->used->index++;
	q->cur_avail_idx++;
    }

    if (!(q->avail->flags & VIRTIO_NO_IRQ_FLAG)) {
	PrintDebug("Raising IRQ %d\n",  virtio->pci_dev->config_header.intr_line);
	v3_pci_raise_irq(virtio->pci_bus, 0, virtio->pci_dev);
	virtio->virtio_cfg.pci_isr = VIRTIO_ISR_ACTIVE;
    }

    return 0;
}


static uint64_t virtio_input(struct v3_vm_info * vm, uint8_t * buf, uint64_t len, void * private_data) {
    struct virtio_console_state * cons_state = private_data;
    struct virtio_queue * q = &(cons_state->queue[0]);
    int xfer_len = 0;
    
   PrintDebug("VIRTIO CONSOLE Handle Input: cur_index=%d (mod=%d), avail_index=%d\n", 
	       q->cur_avail_idx, q->cur_avail_idx % QUEUE_SIZE, q->avail->index);


   if (q->cur_avail_idx != q->avail->index) {
       uint16_t input_idx = q->avail->ring[q->cur_avail_idx % q->queue_size];
       struct vring_desc * input_desc = NULL;
       uint8_t * input_buf = NULL;
 

       input_desc = &(q->desc[input_idx]);

       if (v3_gpa_to_hva(&(cons_state->vm->cores[0]), input_desc->addr_gpa, (addr_t *)&(input_buf)) == -1) {
	   PrintError("Could not translate receive buffer address\n");
	   return 0;
       }

       memset(input_buf, 0, input_desc->length);

       xfer_len = (input_desc->length > len) ? len : input_desc->length;

       memcpy(input_buf, buf, xfer_len);

       
       q->used->ring[q->used->index % q->queue_size].id = q->avail->ring[q->cur_avail_idx % q->queue_size];
       q->used->ring[q->used->index % q->queue_size].length = xfer_len;

       q->used->index++;
       q->cur_avail_idx++;
   }


    // say hello
    if (!(q->avail->flags & VIRTIO_NO_IRQ_FLAG)) {
	    v3_pci_raise_irq(cons_state->pci_bus, 0, cons_state->pci_dev);
	    cons_state->virtio_cfg.pci_isr = 0x1;
    }

    return xfer_len;
}


static int virtio_io_write(struct guest_info * core, uint16_t port, void * src, uint_t length, void * private_data) {
    struct virtio_console_state * virtio = (struct virtio_console_state *)private_data;
    int port_idx = port % virtio->io_range_size;


    PrintDebug("VIRTIO CONSOLE Write for port %d (index=%d) len=%d, value=%x\n", 
	       port, port_idx,  length, *(uint32_t *)src);



    switch (port_idx) {
	case GUEST_FEATURES_PORT:
	    if (length != 4) {
		PrintError("Illegal write length for guest features\n");
		return -1;
	    }
	    
	    virtio->virtio_cfg.guest_features = *(uint32_t *)src;

	    break;
	case VRING_PG_NUM_PORT:
	    if (length == 4) {
		addr_t pfn = *(uint32_t *)src;
		addr_t page_addr = (pfn << VIRTIO_PAGE_SHIFT);


		virtio->cur_queue->pfn = pfn;
		
		virtio->cur_queue->ring_desc_addr = page_addr ;
		virtio->cur_queue->ring_avail_addr = page_addr + (QUEUE_SIZE * sizeof(struct vring_desc));
		virtio->cur_queue->ring_used_addr = ( virtio->cur_queue->ring_avail_addr + \
						 sizeof(struct vring_avail)    + \
						 (QUEUE_SIZE * sizeof(uint16_t)));
		
		// round up to next page boundary.
		virtio->cur_queue->ring_used_addr = (virtio->cur_queue->ring_used_addr + 0xfff) & ~0xfff;

		if (v3_gpa_to_hva(core, virtio->cur_queue->ring_desc_addr, (addr_t *)&(virtio->cur_queue->desc)) == -1) {
		    PrintError("Could not translate ring descriptor address\n");
		    return -1;
		}


		if (v3_gpa_to_hva(core, virtio->cur_queue->ring_avail_addr, (addr_t *)&(virtio->cur_queue->avail)) == -1) {
		    PrintError("Could not translate ring available address\n");
		    return -1;
		}


		if (v3_gpa_to_hva(core, virtio->cur_queue->ring_used_addr, (addr_t *)&(virtio->cur_queue->used)) == -1) {
		    PrintError("Could not translate ring used address\n");
		    return -1;
		}

		PrintDebug("RingDesc_addr=%p, Avail_addr=%p, Used_addr=%p\n",
			   (void *)(virtio->cur_queue->ring_desc_addr),
			   (void *)(virtio->cur_queue->ring_avail_addr),
			   (void *)(virtio->cur_queue->ring_used_addr));

		PrintDebug("RingDesc=%p, Avail=%p, Used=%p\n", 
			   virtio->cur_queue->desc, virtio->cur_queue->avail, virtio->cur_queue->used);

	    } else {
		PrintError("Illegal write length for page frame number\n");
		return -1;
	    }
	    break;
	case VRING_Q_SEL_PORT:
	    virtio->virtio_cfg.vring_queue_selector = *(uint16_t *)src;

	    if (virtio->virtio_cfg.vring_queue_selector > 1) {
		PrintError("Virtio Console device only uses 2 queue, selected %d\n", 
			   virtio->virtio_cfg.vring_queue_selector);
		return -1;
	    }
	    
	    virtio->cur_queue = &(virtio->queue[virtio->virtio_cfg.vring_queue_selector]);

	    break;
	case VRING_Q_NOTIFY_PORT:
	    PrintDebug("Handling Kick\n");
	    if (handle_kick(core, virtio) == -1) {
		PrintError("Could not handle Console Notification\n");
		return -1;
	    }
	    break;
	case VIRTIO_STATUS_PORT:
	    virtio->virtio_cfg.status = *(uint8_t *)src;

	    if (virtio->virtio_cfg.status == 0) {
		PrintDebug("Resetting device\n");
		virtio_reset(virtio);
	    }

	    break;

	case VIRTIO_ISR_PORT:
	    virtio->virtio_cfg.pci_isr = *(uint8_t *)src;
	    break;
	default:
	    return -1;
	    break;
    }

    return length;
}


static int virtio_io_read(struct guest_info * core, uint16_t port, void * dst, uint_t length, void * private_data) {
    struct virtio_console_state * virtio = (struct virtio_console_state *)private_data;
    int port_idx = port % virtio->io_range_size;


    PrintDebug("VIRTIO CONSOLE Read  for port %d (index =%d), length=%d\n", 
	       port, port_idx, length);

    switch (port_idx) {
	case HOST_FEATURES_PORT:
	    if (length != 4) {
		PrintError("Illegal read length for host features\n");
		return -1;
	    }

	    *(uint32_t *)dst = virtio->virtio_cfg.host_features;
	
	    break;
	case VRING_PG_NUM_PORT:
	    if (length != 4) {
		PrintError("Illegal read length for page frame number\n");
		return -1;
	    }

	    *(uint32_t *)dst = virtio->cur_queue->pfn;

	    break;
	case VRING_SIZE_PORT:
	    if (length != 2) {
		PrintError("Illegal read length for vring size\n");
		return -1;
	    }
		
	    *(uint16_t *)dst = virtio->cur_queue->queue_size;

	    break;

	case VIRTIO_STATUS_PORT:
	    if (length != 1) {
		PrintError("Illegal read length for status\n");
		return -1;
	    }

	    *(uint8_t *)dst = virtio->virtio_cfg.status;
	    break;

	case VIRTIO_ISR_PORT:
	    *(uint8_t *)dst = virtio->virtio_cfg.pci_isr;
	    virtio->virtio_cfg.pci_isr = 0;
	    v3_pci_lower_irq(virtio->pci_bus, 0, virtio->pci_dev);
	    break;

	default:
	    if ( (port_idx >= sizeof(struct virtio_config)) && 
		 (port_idx < (sizeof(struct virtio_config) + sizeof(struct console_config))) ) {
		int cfg_offset = port_idx - sizeof(struct virtio_config);
		uint8_t * cfg_ptr = (uint8_t *)&(virtio->cons_cfg);

		memcpy(dst, cfg_ptr + cfg_offset, length);
		
	    } else {
		PrintError("Read of Unhandled Virtio Read\n");
		return -1;
	    }
	  
	    break;
    }

    return length;
}




static int connect_fn(struct v3_vm_info * vm, 
		      void * frontend_data, 
		      struct v3_dev_char_ops * ops, 
		      v3_cfg_tree_t * cfg, 
		      void * private_data, 
		      void ** push_fn_arg) {

    struct virtio_console_state * state = (struct virtio_console_state *)frontend_data;

    state->ops = ops;
    state->backend_data = private_data;

    state->ops->input = virtio_input;
    *push_fn_arg = state;

    return 0;
}

static int virtio_free(struct virtio_console_state * virtio) {

    // unregister from PCI

    V3_Free(virtio);
    return 0;
}


static struct v3_device_ops dev_ops = {
    .free = (int (*)(void *))virtio_free,

};




static int virtio_init(struct v3_vm_info * vm, v3_cfg_tree_t * cfg) {
    struct vm_device * pci_bus = v3_find_dev(vm, v3_cfg_val(cfg, "bus"));
    struct virtio_console_state * virtio_state = NULL;
    struct pci_device * pci_dev = NULL;
    char * dev_id = v3_cfg_val(cfg, "ID");

    PrintDebug("Initializing VIRTIO Console device\n");

    if (pci_bus == NULL) {
	PrintError("VirtIO devices require a PCI Bus");
	return -1;
    }

    
    virtio_state = (struct virtio_console_state *)V3_Malloc(sizeof(struct virtio_console_state));
    memset(virtio_state, 0, sizeof(struct virtio_console_state));
    

    cons_state = virtio_state;
    cons_state->vm = vm;

   

    struct vm_device * dev = v3_add_device(vm, dev_id, &dev_ops, virtio_state);

    if (dev == NULL) {
	PrintError("Could not attach device %s\n", dev_id);
	V3_Free(virtio_state);
	return -1;
    }

    // PCI initialization
    {
	struct v3_pci_bar bars[6];
	int num_ports = sizeof(struct virtio_config) + sizeof(struct console_config);
	int tmp_ports = num_ports;
	int i;


	// This gets the number of ports, rounded up to a power of 2
	virtio_state->io_range_size = 1; // must be a power of 2

	while (tmp_ports > 0) {
	    tmp_ports >>= 1;
	    virtio_state->io_range_size <<= 1;
	}
	
	// this is to account for any low order bits being set in num_ports
	// if there are none, then num_ports was already a power of 2 so we shift right to reset it
	if ((num_ports & ((virtio_state->io_range_size >> 1) - 1)) == 0) {
	    virtio_state->io_range_size >>= 1;
	}


	for (i = 0; i < 6; i++) {
	    bars[i].type = PCI_BAR_NONE;
	}

	bars[0].type = PCI_BAR_IO;
	bars[0].default_base_port = -1;
	bars[0].num_ports = virtio_state->io_range_size;

	bars[0].io_read = virtio_io_read;
	bars[0].io_write = virtio_io_write;
	bars[0].private_data = virtio_state;
	

	pci_dev = v3_pci_register_device(pci_bus, PCI_STD_DEVICE, 
					 0, PCI_AUTO_DEV_NUM, 0,
					 "LNX_VIRTIO_CONSOLE", bars,
					 NULL, NULL, NULL, virtio_state);

	if (!pci_dev) {
	    PrintError("Could not register PCI Device\n");
	    v3_remove_device(dev);
	    return -1;
	}
	
	pci_dev->config_header.vendor_id = VIRTIO_VENDOR_ID;
	pci_dev->config_header.subsystem_vendor_id = VIRTIO_SUBVENDOR_ID;
	

	pci_dev->config_header.device_id = VIRTIO_CONSOLE_DEV_ID;
	pci_dev->config_header.class = PCI_CLASS_DISPLAY;
	pci_dev->config_header.subclass = PCI_DISPLAY_SUBCLASS_OTHER;
    
	pci_dev->config_header.subsystem_id = VIRTIO_CONSOLE_SUBDEVICE_ID;

	pci_dev->config_header.intr_pin = 1;

	pci_dev->config_header.max_latency = 1; // ?? (qemu does it...)


	virtio_state->pci_dev = pci_dev;
	virtio_state->pci_bus = pci_bus;
    }

    virtio_reset(virtio_state);

    if (v3_dev_add_char_frontend(vm, dev_id, connect_fn, (void *)virtio_state) == -1) {
	PrintError("Could not register %s as frontend\n", dev_id);
	v3_remove_device(dev);
	return -1;
    }


    return 0;
}


device_register("LNX_VIRTIO_CONSOLE", virtio_init)