#include <linux/module.h>
#include <linux/version.h>
#include <linux/proc_fs.h>
#include <linux/cdev.h>
#include <linux/pci.h>

/*************************************************************************************************/
MODULE_AUTHOR("h4ndh"); //hessamoddin hediyehloo
MODULE_AUTHOR("alihatamitajik");
MODULE_LICENSE("Dual BSD/GPL");

/*************************************************************************************************/
#define VENDOR_ID 0x10EE
#define DEVICE_ID 0x7024

struct pci_device_id pcie_ids[] = 
{
    {PCI_DEVICE(VENDOR_ID, DEVICE_ID)},
    {0, }
};

MODULE_DEVICE_TABLE(pci, pcie_ids);

/*************************************************************************************************/
static struct pci_dev *pcidev = NULL;

/*************************************************************************************************/
static int pcie_init(void);
static void pcie_exit(void);
static int pcie_probe (struct pci_dev *dev, const struct pci_device_id *id);
static void pcie_remove(struct pci_dev *dev);

static int proc_init(void);

static int sono_bar_open(struct inode *inode, struct file *flip);
static int sono_bar_close(struct inode *inode, struct file *filp);
static int sono_bar_mmap(struct file *filp, struct vm_area_struct *vma);

static int sono_buffer_open(struct inode *inode, struct file *flip);
static int sono_buffer_close(struct inode *inode, struct file *filp);
static int sono_buffer_mmap(struct file *filp, struct vm_area_struct *vma);

static int create_dma_buffer(void);

static void release_dma_buffer(int num);
static void unmap_bar_buffer(int num);

static void pass_dma_address_to_hw(void);

/*************************************************************************************************/
#define DEV_NAME  "sonoDevice"
#define CLASS_NAME  "sonoClass"

/*************************************************************************************************/
#define TOTAL_BAR_NUM 3

struct bar_t {
  resource_size_t start_addr;
  resource_size_t end_addr;
  resource_size_t length;
  unsigned long flags;
  void* bar_ptr;
};

struct bar_t bars[TOTAL_BAR_NUM];

/*************************************************************************************************/
#define TOTAL_BUFFER_NUM  16

struct buffer_t {
  void * ptr;
  dma_addr_t address;
};

struct buffer_t buffers[TOTAL_BUFFER_NUM];

/*************************************************************************************************/
#define DMA_SIZE 4*1024*1024

/*************************************************************************************************/
static struct pci_driver pci_driver =
{
  .name = CLASS_NAME,
  .id_table = pcie_ids,
	.probe = pcie_probe,
	.remove = __exit_p(pcie_remove),
};

/*************************************************************************************************/
static struct proc_ops bar_ops = 
{
  .proc_open = sono_bar_open,
  .proc_release = sono_bar_close,
  .proc_mmap = sono_bar_mmap
};

static struct proc_ops buffer_ops = 
{
  .proc_open = sono_buffer_open,
  .proc_release = sono_buffer_close,
  .proc_mmap = sono_buffer_mmap
};

/*************************************************************************************************/
#define PRINT_PREFIX  "Sono pcie driver"
#define PRINT_ALERT(STR)  printk(KERN_ALERT "%s %s\n", PRINT_PREFIX, STR)
#define PRINT_WARN(STR)  printk(KERN_WARN "%s %s\n", PRINT_PREFIX, STR)

/*************************************************************************************************/
static int __init pcie_init(void)
{
  int res = 0;
	PRINT_ALERT("driver initializing");
  
	res = pci_register_driver(&pci_driver);
	if ( res ) {
		PRINT_ALERT("device not found");
		return res;
	}

	PRINT_ALERT("register driver success" );

	res = proc_init();
	if ( res ) {
		PRINT_ALERT("proc file creation failed");
		return res;
	}

	PRINT_ALERT("driver loaded");
	return res;
}

/*************************************************************************************************/
static int proc_init(void)
{
  PRINT_ALERT("proc_init");

  proc_create("sono_bars", 0, NULL, &bar_ops);
  proc_create("sono_buffers", 0, NULL, &buffer_ops);

  return 0;
}

/*************************************************************************************************/
static int sono_bar_open(struct inode *inode, struct file *filp)
{
  return 0;
}

/*************************************************************************************************/
static int sono_buffer_open(struct inode *inode, struct file *filp)
{
  return 0;
}

/*************************************************************************************************/
static int sono_bar_close(struct inode *inode, struct file *filp)
{
	return 0;
}

/*************************************************************************************************/
static int sono_buffer_close(struct inode *inode, struct file *filp)
{
	return 0;
}

/*************************************************************************************************/
static int sono_bar_mmap(struct file *filp, struct vm_area_struct *vma)
{
  PRINT_ALERT("BAR MMAP");

  unsigned long offset = vma->vm_pgoff;
  int bar_num = offset;

  unsigned long physical = bars[bar_num].start_addr;
  unsigned long bar_size = bars[bar_num].length;
  unsigned long vsize = vma->vm_end - vma->vm_start;
  
  if(vsize > bar_size)
        return -EINVAL;


  #if LINUX_VERSION_CODE <= KERNEL_VERSION(5,4,0)
    vma->vm_flags |= VM_IO;// ubuntu 14
  #elif LINUX_VERSION_CODE <= KERNEL_VERSION(6,8,0)
    vm_flags_set(vma, VM_IO);
  #endif
  
  vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
  int res = remap_pfn_range(vma, vma->vm_start, physical >> PAGE_SHIFT, vsize, vma->vm_page_prot);
  if(res) 
  {
      printk(KERN_ERR "Failed to map bar @ %d\n", bar_num);
  }
  
  return res;
}

/*************************************************************************************************/
static int sono_buffer_mmap(struct file *filp, struct vm_area_struct *vma)
{
  PRINT_ALERT("BUFFER MMAP");

  unsigned long offset = vma->vm_pgoff;
  int buffer_num = offset;

  unsigned long physical = virt_to_phys(buffers[buffer_num].ptr);
  unsigned long vsize = vma->vm_end - vma->vm_start;

  if(vsize > DMA_SIZE)
      return -EINVAL;

  int res = remap_pfn_range(vma, vma->vm_start, physical >> PAGE_SHIFT, vsize, vma->vm_page_prot);       
  if(res) 
  {
      printk(KERN_ERR "failed to map mapped DMA buffer at phys: %p\n", buffers[buffer_num].address);
  }
  
  return res;
}

/*************************************************************************************************/
static int create_dma_buffer()
{
  int i = 0;
  for(; i < TOTAL_BUFFER_NUM; i++)
  {
    buffers[i].ptr = dma_alloc_coherent(&pcidev->dev, DMA_SIZE, &buffers[i].address, GFP_USER);
    if(buffers[i].ptr == NULL) 
    {
      PRINT_ALERT("I can't allocate the DMA buffer");
      while(--i >= 0)
      {
        release_dma_buffer(i);
      }
      return 1;
    }
  }

  return 0;
}

/*************************************************************************************************/
static int __init pcie_probe (struct pci_dev *dev, const struct pci_device_id *id)
{ 
  int rc = 0;

 if(pcidev)
 {
   PRINT_ALERT("Cant handle more than one device at a time");

   return -EINVAL;
 }

  pcidev = dev;

  rc = pci_enable_device(dev);
  if(rc)
  {
    PRINT_ALERT("driver pci_enable_device() failed");
	  goto probe_fail_enable;
  }

  if (!dma_set_mask(&pcidev->dev, DMA_BIT_MASK(64))) 
  {
    if (dma_set_coherent_mask(&pcidev->dev, DMA_BIT_MASK(64))) 
    {
      printk(KERN_ERR "Unable to obtain 64bit DMA for consistent allocations\n");
      rc = 1;
      goto probe_fail;
    }
  }

  create_dma_buffer();

  rc = pci_request_regions(pcidev, DEV_NAME);
  if(rc)
  {
    PRINT_ALERT("Failed to request regoins");
    goto probe_fail;  
  }

  
  for(int i = 0; i < TOTAL_BAR_NUM; i++) 
  {
    bars[i].flags = pci_resource_flags(pcidev, i);
    if (!(bars[i].flags & IORESOURCE_MEM)) {
      printk(KERN_ERR "Sono pcie driver incorrect BAR configuration\n" );
      rc = 1;
      goto probe_fail_release_region;
    } 

    bars[i].start_addr = pci_resource_start(pcidev, i);
    bars[i].end_addr = pci_resource_end(pcidev, i);
    bars[i].length = pci_resource_len(pcidev, i);

    bars[i].bar_ptr = pci_iomap(pcidev, i, bars[i].length);

    u32* temp = (u32*)bars[i].bar_ptr;

    if(temp == 0)
    {
      printk(KERN_ERR "driver failed to map BAR %d\n", i);
      rc = 1;
      while(--i >= 0)
      {
        unmap_bar_buffer(i);
      }
      for(; i < TOTAL_BUFFER_NUM; i++) 
      {
        release_dma_buffer(i);
      }
      goto probe_fail_release_region;
    }
  }

  pci_set_master(dev);

  pass_dma_address_to_hw();

  return 0;

  probe_fail_release_region:
    pci_release_regions(dev);
  probe_fail:
    pci_disable_device(dev);
  probe_fail_enable:
    return rc;
}

/*************************************************************************************************/
static void pcie_remove(struct pci_dev *dev)
{
  PRINT_ALERT("remove driver");

	pci_clear_master(dev);
	PRINT_ALERT("Cleared PCIe master");

  int i = 0;
  for(; i < TOTAL_BAR_NUM ; i++) 
  {
    unmap_bar_buffer(i);
  }

  for(; i < TOTAL_BUFFER_NUM ; i++) 
  {
    release_dma_buffer(i);
  }

	PRINT_ALERT("IOunmap");

	pci_release_regions(dev);
	PRINT_ALERT("pci_release_regions");

	pci_disable_device(dev);
	PRINT_ALERT("pci_disable_device");
}

/*************************************************************************************************/
static void __exit pcie_exit(void)
{
	PRINT_ALERT("driver unloading");

	PRINT_ALERT("driver unregistering");
	pci_unregister_driver(&pci_driver);
  
  remove_proc_entry("sono_bars", NULL);
  remove_proc_entry("sono_buffers", NULL);
  
	PRINT_ALERT("driver unloaded");
}

module_init(pcie_init);
module_exit(pcie_exit);
/*************************************************************************************************/
void release_dma_buffer(int num)
{
  dma_free_coherent(&pcidev->dev, DMA_SIZE, buffers[num].ptr, buffers[num].address);
}
/*************************************************************************************************/
void unmap_bar_buffer(int num)
{
  pci_iounmap(pcidev, bars[num].bar_ptr);
}
/*************************************************************************************************/
//This function is tightly coupled with hw def
void pass_dma_address_to_hw(void)
{
  int index = 0x00002060;

  u32* temp = (u32*)bars[2].bar_ptr;

  int i;
  for(i = 0; i < TOTAL_BUFFER_NUM; i++)
  {
    dma_addr_t address = buffers[i].address;

    temp[index / 4] =  address >> 32;
    index += 4;

    temp[index / 4] = (address & 0xFFFFFFFF);
    index += 4;
  }
}
/*************************************************************************************************/
/*************************************************************************************************/
/*************************************************************************************************/