#include <linux/sched.h>
#include <linux/errno.h>
#include <linux/freezer.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/kthread.h>
#include <linux/mutex.h>
#include <linux/utsname.h>

#include <scsi/scsi.h>
#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>

#include "usb.h"
#include "scsiglue.h"
#include "smil.h"
#include "transport.h"

/* Some informational data */
MODULE_AUTHOR("Domao");
MODULE_DESCRIPTION("ENE USB Mass Storage driver for Linux");
MODULE_LICENSE("GPL");

static unsigned int delay_use = 1;

static struct usb_device_id eucr_usb_ids[] = {
	{ USB_DEVICE(0x058f, 0x6366) },
	{ USB_DEVICE(0x0cf2, 0x6230) },
	{ USB_DEVICE(0x0cf2, 0x6250) },
	{ }                                            /* Terminating entry */
};
MODULE_DEVICE_TABLE(usb, eucr_usb_ids);


#ifdef CONFIG_PM

static int eucr_suspend(struct usb_interface *iface, pm_message_t message)
{
	struct us_data *us = usb_get_intfdata(iface);
	pr_info("--- eucr_suspend ---\n");
	/* Wait until no command is running */
	mutex_lock(&us->dev_mutex);

	if (us->suspend_resume_hook)
		(us->suspend_resume_hook)(us, US_SUSPEND);

	mutex_unlock(&us->dev_mutex);
	return 0;
}

static int eucr_resume(struct usb_interface *iface)
{
	u8    tmp = 0;

	struct us_data *us = usb_get_intfdata(iface);
	pr_info("--- eucr_resume---\n");
	mutex_lock(&us->dev_mutex);

	if (us->suspend_resume_hook)
		(us->suspend_resume_hook)(us, US_RESUME);


	mutex_unlock(&us->dev_mutex);

	us->Power_IsResum = true;

	us->SM_Status = *(struct keucr_sm_status *)&tmp;

	return 0;
}

static int eucr_reset_resume(struct usb_interface *iface)
{
	u8    tmp = 0;
	struct us_data *us = usb_get_intfdata(iface);

	pr_info("--- eucr_reset_resume---\n");

	/* Report the reset to the SCSI core */
	usb_stor_report_bus_reset(us);

	/*
	 * FIXME: Notify the subdrivers that they need to reinitialize
	 * the device
	 */

	us->Power_IsResum = true;

	us->SM_Status = *(struct keucr_sm_status *)&tmp;

	return 0;
}

#else

#define eucr_suspend		NULL
#define eucr_resume		NULL
#define eucr_reset_resume	NULL

#endif

static int eucr_pre_reset(struct usb_interface *iface)
{
	struct us_data *us = usb_get_intfdata(iface);

	pr_info("usb --- eucr_pre_reset\n");

	/* Make sure no command runs during the reset */
	mutex_lock(&us->dev_mutex);
	return 0;
}

static int eucr_post_reset(struct usb_interface *iface)
{
	struct us_data *us = usb_get_intfdata(iface);

	pr_info("usb --- eucr_post_reset\n");

	/* Report the reset to the SCSI core */
	usb_stor_report_bus_reset(us);

	mutex_unlock(&us->dev_mutex);
	return 0;
}

void fill_inquiry_response(struct us_data *us, unsigned char *data,
							unsigned int data_len)
{
	pr_info("usb --- fill_inquiry_response\n");
	if (data_len < 36) /* You lose. */
		return;

	if (data[0]&0x20) {
		memset(data+8, 0, 28);
	} else {
		u16 bcdDevice =
			le16_to_cpu(us->pusb_dev->descriptor.bcdDevice);
		memcpy(data+8, us->unusual_dev->vendorName,
			strlen(us->unusual_dev->vendorName) > 8 ? 8 :
			strlen(us->unusual_dev->vendorName));
		memcpy(data+16, us->unusual_dev->productName,
			strlen(us->unusual_dev->productName) > 16 ? 16 :
			strlen(us->unusual_dev->productName));
		data[32] = 0x30 + ((bcdDevice>>12) & 0x0F);
		data[33] = 0x30 + ((bcdDevice>>8) & 0x0F);
		data[34] = 0x30 + ((bcdDevice>>4) & 0x0F);
		data[35] = 0x30 + ((bcdDevice) & 0x0F);
	}
	usb_stor_set_xfer_buf(us, data, data_len, us->srb, TO_XFER_BUF);
}

static int usb_stor_control_thread(void *__us)
{
	struct us_data *us = (struct us_data *)__us;
	struct Scsi_Host *host = us_to_host(us);

	pr_info("usb --- usb_stor_control_thread\n");
	for (;;) {
		if (wait_for_completion_interruptible(&us->cmnd_ready))
			break;

		/* lock the device pointers */
		mutex_lock(&(us->dev_mutex));

		/* if the device has disconnected, we are free to exit */
		if (test_bit(US_FLIDX_DISCONNECTING, &us->dflags)) {
			mutex_unlock(&us->dev_mutex);
			break;
		}

		/* lock access to the state */
		scsi_lock(host);

		/* When we are called with no command pending, we're done */
		if (us->srb == NULL) {
			scsi_unlock(host);
			mutex_unlock(&us->dev_mutex);
			break;
		}

		/* has the command timed out *already* ? */
		if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
			us->srb->result = DID_ABORT << 16;
			goto SkipForAbort;
		}

		scsi_unlock(host);

		if (us->srb->sc_data_direction == DMA_BIDIRECTIONAL) {
			us->srb->result = DID_ERROR << 16;
		} else if (us->srb->device->id
			   && !(us->fflags & US_FL_SCM_MULT_TARG)) {
			us->srb->result = DID_BAD_TARGET << 16;
		} else if (us->srb->device->lun > us->max_lun) {
			us->srb->result = DID_BAD_TARGET << 16;
		} else if ((us->srb->cmnd[0] == INQUIRY)
			   && (us->fflags & US_FL_FIX_INQUIRY)) {
			unsigned char data_ptr[36] = {0x00, 0x80, 0x02, 0x02,
						0x1F, 0x00, 0x00, 0x00};

			fill_inquiry_response(us, data_ptr, 36);
			us->srb->result = SAM_STAT_GOOD;
		} else {
			us->proto_handler(us->srb, us);
		}

		/* lock access to the state */
		scsi_lock(host);

		/* indicate that the command is done */
		if (us->srb->result != DID_ABORT << 16) {
			us->srb->scsi_done(us->srb);
		} else {
SkipForAbort:
			pr_info("scsi command aborted\n");
		}

		if (test_bit(US_FLIDX_TIMED_OUT, &us->dflags)) {
			complete(&(us->notify));

			/* Allow USB transfers to resume */
			clear_bit(US_FLIDX_ABORTING, &us->dflags);
			clear_bit(US_FLIDX_TIMED_OUT, &us->dflags);
		}

		/* finished working on this command */
		us->srb = NULL;
		scsi_unlock(host);

		/* unlock the device pointers */
		mutex_unlock(&us->dev_mutex);
	} /* for (;;) */

	/* Wait until we are told to stop */
	for (;;) {
		set_current_state(TASK_INTERRUPTIBLE);
		if (kthread_should_stop())
			break;
		schedule();
	}
	__set_current_state(TASK_RUNNING);
	return 0;
}

static int associate_dev(struct us_data *us, struct usb_interface *intf)
{
	pr_info("usb --- associate_dev\n");

	/* Fill in the device-related fields */
	us->pusb_dev = interface_to_usbdev(intf);
	us->pusb_intf = intf;
	us->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;

	/* Store our private data in the interface */
	usb_set_intfdata(intf, us);

	/* Allocate the device-related DMA-mapped buffers */
	us->cr = usb_alloc_coherent(us->pusb_dev, sizeof(*us->cr), GFP_KERNEL,
							&us->cr_dma);
	if (!us->cr) {
		pr_info("usb_ctrlrequest allocation failed\n");
		return -ENOMEM;
	}

	us->iobuf = usb_alloc_coherent(us->pusb_dev, US_IOBUF_SIZE, GFP_KERNEL,
							&us->iobuf_dma);
	if (!us->iobuf) {
		pr_info("I/O buffer allocation failed\n");
		return -ENOMEM;
	}

	us->sensebuf = kmalloc(US_SENSE_SIZE, GFP_KERNEL);
	if (!us->sensebuf)
		return -ENOMEM;

	return 0;
}

static int get_device_info(struct us_data *us, const struct usb_device_id *id)
{
	struct usb_device *dev = us->pusb_dev;
	struct usb_interface_descriptor *idesc =
					&us->pusb_intf->cur_altsetting->desc;

	pr_info("usb --- get_device_info\n");

	us->subclass = idesc->bInterfaceSubClass;
	us->protocol = idesc->bInterfaceProtocol;
	us->fflags = id->driver_info;
	us->Power_IsResum = false;

	if (us->fflags & US_FL_IGNORE_DEVICE) {
		pr_info("device ignored\n");
		return -ENODEV;
	}

	if (dev->speed != USB_SPEED_HIGH)
		us->fflags &= ~US_FL_GO_SLOW;

	return 0;
}

static int get_transport(struct us_data *us)
{
	pr_info("usb --- get_transport\n");
	switch (us->protocol) {
	case USB_PR_BULK:
		us->transport_name = "Bulk";
		us->transport = usb_stor_Bulk_transport;
		us->transport_reset = usb_stor_Bulk_reset;
		break;

	default:
		return -EIO;
	}

	/* fix for single-lun devices */
	if (us->fflags & US_FL_SINGLE_LUN)
		us->max_lun = 0;
	return 0;
}

static int get_protocol(struct us_data *us)
{
	pr_info("usb --- get_protocol\n");
	pr_info("us->pusb_dev->descriptor.idVendor = %x\n",
			us->pusb_dev->descriptor.idVendor);
	pr_info("us->pusb_dev->descriptor.idProduct = %x\n",
			us->pusb_dev->descriptor.idProduct);
	switch (us->subclass) {
	case USB_SC_SCSI:
		us->protocol_name = "Transparent SCSI";
		if ((us->pusb_dev->descriptor.idVendor == 0x0CF2)
		    && (us->pusb_dev->descriptor.idProduct == 0x6250))
			us->proto_handler = ENE_stor_invoke_transport;
		else
			us->proto_handler = usb_stor_invoke_transport;
		break;

	default:
		return -EIO;
	}
	return 0;
}

static int get_pipes(struct us_data *us)
{
	struct usb_host_interface *altsetting = us->pusb_intf->cur_altsetting;
	int i;
	struct usb_endpoint_descriptor *ep;
	struct usb_endpoint_descriptor *ep_in = NULL;
	struct usb_endpoint_descriptor *ep_out = NULL;
	struct usb_endpoint_descriptor *ep_int = NULL;

	pr_info("usb --- get_pipes\n");

	for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
		ep = &altsetting->endpoint[i].desc;

		if (usb_endpoint_xfer_bulk(ep)) {
			if (usb_endpoint_dir_in(ep)) {
				if (!ep_in)
					ep_in = ep;
			} else {
				if (!ep_out)
					ep_out = ep;
			}
		} else if (usb_endpoint_is_int_in(ep)) {
			if (!ep_int)
				ep_int = ep;
		}
	}

	if (!ep_in || !ep_out || (us->protocol == USB_PR_CBI && !ep_int)) {
		pr_info("Endpoint sanity check failed! Rejecting dev.\n");
		return -EIO;
	}

	/* Calculate and store the pipe values */
	us->send_ctrl_pipe = usb_sndctrlpipe(us->pusb_dev, 0);
	us->recv_ctrl_pipe = usb_rcvctrlpipe(us->pusb_dev, 0);
	us->send_bulk_pipe = usb_sndbulkpipe(us->pusb_dev,
			ep_out->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	us->recv_bulk_pipe = usb_rcvbulkpipe(us->pusb_dev,
			ep_in->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	if (ep_int) {
		us->recv_intr_pipe = usb_rcvintpipe(us->pusb_dev,
			ep_int->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
		us->ep_bInterval = ep_int->bInterval;
	}
	return 0;
}

static int usb_stor_acquire_resources(struct us_data *us)
{
	struct task_struct *th;

	pr_info("usb --- usb_stor_acquire_resources\n");
	us->current_urb = usb_alloc_urb(0, GFP_KERNEL);
	if (!us->current_urb) {
		pr_info("URB allocation failed\n");
		return -ENOMEM;
	}

	/* Start up our control thread */
	th = kthread_run(usb_stor_control_thread, us, "eucr-storage");
	if (IS_ERR(th)) {
		pr_info("Unable to start control thread\n");
		return PTR_ERR(th);
	}
	us->ctl_thread = th;

	return 0;
}

static void usb_stor_release_resources(struct us_data *us)
{
	pr_info("usb --- usb_stor_release_resources\n");

	SM_FreeMem();

	complete(&us->cmnd_ready);
	if (us->ctl_thread)
		kthread_stop(us->ctl_thread);

	/* Call the destructor routine, if it exists */
	if (us->extra_destructor) {
		pr_info("-- calling extra_destructor()\n");
		us->extra_destructor(us->extra);
	}

	/* Free the extra data and the URB */
	kfree(us->extra);
	usb_free_urb(us->current_urb);
}

static void dissociate_dev(struct us_data *us)
{
	pr_info("usb --- dissociate_dev\n");

	kfree(us->sensebuf);

	/* Free the device-related DMA-mapped buffers */
	usb_free_coherent(us->pusb_dev, sizeof(*us->cr), us->cr, us->cr_dma);
	usb_free_coherent(us->pusb_dev, US_IOBUF_SIZE, us->iobuf,
			  us->iobuf_dma);

	/* Remove our private data from the interface */
	usb_set_intfdata(us->pusb_intf, NULL);
}

static void quiesce_and_remove_host(struct us_data *us)
{
	struct Scsi_Host *host = us_to_host(us);

	pr_info("usb --- quiesce_and_remove_host\n");

	/* If the device is really gone, cut short reset delays */
	if (us->pusb_dev->state == USB_STATE_NOTATTACHED)
		set_bit(US_FLIDX_DISCONNECTING, &us->dflags);

	/*
	 * Prevent SCSI-scanning (if it hasn't started yet)
	 * and wait for the SCSI-scanning thread to stop.
	 */
	set_bit(US_FLIDX_DONT_SCAN, &us->dflags);
	wake_up(&us->delay_wait);
	wait_for_completion(&us->scanning_done);

	/*
	 * Removing the host will perform an orderly shutdown: caches
	 * synchronized, disks spun down, etc.
	 */
	scsi_remove_host(host);

	/*
	 * Prevent any new commands from being accepted and cut short
	 * reset delays.
	 */
	scsi_lock(host);
	set_bit(US_FLIDX_DISCONNECTING, &us->dflags);
	scsi_unlock(host);
	wake_up(&us->delay_wait);
}

static void release_everything(struct us_data *us)
{
	pr_info("usb --- release_everything\n");

	usb_stor_release_resources(us);
	dissociate_dev(us);
	scsi_host_put(us_to_host(us));
}

static int usb_stor_scan_thread(void *__us)
{
	struct us_data *us = (struct us_data *)__us;

	pr_info("usb --- usb_stor_scan_thread\n");
	pr_info("EUCR : device found at %d\n", us->pusb_dev->devnum);

	set_freezable();
	/* Wait for the timeout to expire or for a disconnect */
	if (delay_use > 0) {
		wait_event_freezable_timeout(us->delay_wait,
				test_bit(US_FLIDX_DONT_SCAN, &us->dflags),
				delay_use * HZ);
	}

	/* If the device is still connected, perform the scanning */
	if (!test_bit(US_FLIDX_DONT_SCAN, &us->dflags)) {
		/* For bulk-only devices, determine the max LUN value */
		if (us->protocol == USB_PR_BULK
		    && !(us->fflags & US_FL_SINGLE_LUN)) {
			mutex_lock(&us->dev_mutex);
			us->max_lun = usb_stor_Bulk_max_lun(us);
			mutex_unlock(&us->dev_mutex);
		}
		scsi_scan_host(us_to_host(us));
		pr_info("EUCR : device scan complete\n");
	}
	complete_and_exit(&us->scanning_done, 0);
}

static int eucr_probe(struct usb_interface *intf,
					const struct usb_device_id *id)
{
	struct Scsi_Host *host;
	struct us_data *us;
	int result;
	u8	MiscReg03 = 0;
	struct task_struct *th;

	pr_info("usb --- eucr_probe\n");

	host = scsi_host_alloc(&usb_stor_host_template, sizeof(*us));
	if (!host) {
		pr_info("Unable to allocate the scsi host\n");
		return -ENOMEM;
	}

	/* Allow 16-byte CDBs and thus > 2TB */
	host->max_cmd_len = 16;
	us = host_to_us(host);
	memset(us, 0, sizeof(struct us_data));
	mutex_init(&(us->dev_mutex));
	init_completion(&us->cmnd_ready);
	init_completion(&(us->notify));
	init_waitqueue_head(&us->delay_wait);
	init_completion(&us->scanning_done);

	/* Associate the us_data structure with the USB device */
	result = associate_dev(us, intf);
	if (result)
		goto BadDevice;

	/* Get Device info */
	result = get_device_info(us, id);
	if (result)
		goto BadDevice;

	/* Get the transport, protocol, and pipe settings */
	result = get_transport(us);
	if (result)
		goto BadDevice;
	result = get_protocol(us);
	if (result)
		goto BadDevice;
	result = get_pipes(us);
	if (result)
		goto BadDevice;

	/* Acquire all the other resources and add the host */
	result = usb_stor_acquire_resources(us);
	if (result)
		goto BadDevice;

	result = scsi_add_host(host, &intf->dev);
	if (result) {
		pr_info("Unable to add the scsi host\n");
		goto BadDevice;
	}

	/* Start up the thread for delayed SCSI-device scanning */
	th = kthread_create(usb_stor_scan_thread, us, "eucr-stor-scan");
	if (IS_ERR(th)) {
		pr_info("Unable to start the device-scanning thread\n");
		complete(&us->scanning_done);
		quiesce_and_remove_host(us);
		result = PTR_ERR(th);
		goto BadDevice;
	}
	wake_up_process(th);

	/* probe card type */
	result = ene_read_byte(us, REG_CARD_STATUS, &MiscReg03);
	if (result != USB_STOR_XFER_GOOD) {
		result = USB_STOR_TRANSPORT_ERROR;
		quiesce_and_remove_host(us);
		goto BadDevice;
	}

	if (!(MiscReg03 & 0x02)) {
		result = -ENODEV;
		quiesce_and_remove_host(us);
		pr_info("keucr: The driver only supports SM/MS card. To use SD card, please build driver/usb/storage/ums-eneub6250.ko\n");
		goto BadDevice;
	}

	return 0;

	/* We come here if there are any problems */
BadDevice:
	pr_info("usb --- eucr_probe failed\n");
	release_everything(us);
	return result;
}

static void eucr_disconnect(struct usb_interface *intf)
{
	struct us_data *us = usb_get_intfdata(intf);

	pr_info("usb --- eucr_disconnect\n");
	quiesce_and_remove_host(us);
	release_everything(us);
}

/* Initialization and registration */
static struct usb_driver usb_storage_driver = {
	.name =		"eucr",
	.probe =		eucr_probe,
	.suspend =	    eucr_suspend,
	.resume =	    eucr_resume,
	.reset_resume =	eucr_reset_resume,
	.disconnect =	eucr_disconnect,
	.pre_reset =	eucr_pre_reset,
	.post_reset =	eucr_post_reset,
	.id_table =		eucr_usb_ids,
	.soft_unbind =	1,
};

module_usb_driver(usb_storage_driver);