ub.c

Linux Kernel 2.6.9 for OMAP1710

	cmd->state = UB_CMDST_INIT;
	cmd->done = ub_probe_done;
	cmd->back = &compl;

	spin_lock_irqsave(&sc->lock, flags);
	cmd->tag = sc->tagcnt++;

	rc = ub_submit_scsi(sc, cmd);
	spin_unlock_irqrestore(&sc->lock, flags);

	if (rc != 0) {
		printk("ub: testing ready: submit error (%d)\n", rc); /* P3 */
		goto err_submit;
	}

	wait_for_completion(&compl);

	rc = cmd->error;

err_submit:
	kfree(cmd);
err_alloc:
	return rc;
}

/*
 * Read the SCSI capacity synchronously (for probing).
 */
static int ub_sync_read_cap(struct ub_dev *sc, struct ub_capacity *ret)
{
	struct ub_scsi_cmd *cmd;
	char *p;
	enum { ALLOC_SIZE = sizeof(struct ub_scsi_cmd) + 8 };
	unsigned long flags;
	unsigned int bsize, shift;
	unsigned long nsec;
	struct completion compl;
	int rc;

	init_completion(&compl);

	rc = -ENOMEM;
	if ((cmd = kmalloc(ALLOC_SIZE, GFP_KERNEL)) == NULL)
		goto err_alloc;
	memset(cmd, 0, ALLOC_SIZE);
	p = (char *)cmd + sizeof(struct ub_scsi_cmd);

	cmd->cdb[0] = 0x25;
	cmd->cdb_len = 10;
	cmd->dir = UB_DIR_READ;
	cmd->state = UB_CMDST_INIT;
	cmd->data = p;
	cmd->len = 8;
	cmd->done = ub_probe_done;
	cmd->back = &compl;

	spin_lock_irqsave(&sc->lock, flags);
	cmd->tag = sc->tagcnt++;

	rc = ub_submit_scsi(sc, cmd);
	spin_unlock_irqrestore(&sc->lock, flags);

	if (rc != 0) {
		printk("ub: reading capacity: submit error (%d)\n", rc); /* P3 */
		goto err_submit;
	}

	wait_for_completion(&compl);

	if (cmd->error != 0) {
		printk("ub: reading capacity: error %d\n", cmd->error); /* P3 */
		rc = -EIO;
		goto err_read;
	}
	if (cmd->act_len != 8) {
		printk("ub: reading capacity: size %d\n", cmd->act_len); /* P3 */
		rc = -EIO;
		goto err_read;
	}

	/* sd.c special-cases sector size of 0 to mean 512. Needed? Safe? */
	nsec = be32_to_cpu(*(u32 *)p) + 1;
	bsize = be32_to_cpu(*(u32 *)(p + 4));
	switch (bsize) {
	case 512:	shift = 0;	break;
	case 1024:	shift = 1;	break;
	case 2048:	shift = 2;	break;
	case 4096:	shift = 3;	break;
	default:
		printk("ub: Bad sector size %u\n", bsize); /* P3 */
		rc = -EDOM;
		goto err_inv_bsize;
	}

	ret->bsize = bsize;
	ret->bshift = shift;
	ret->nsec = nsec << shift;
	rc = 0;

err_inv_bsize:
err_read:
err_submit:
	kfree(cmd);
err_alloc:
	return rc;
}

/*
 */
static void ub_probe_urb_complete(struct urb *urb, struct pt_regs *pt)
{
	struct completion *cop = urb->context;
	complete(cop);
}

static void ub_probe_timeout(unsigned long arg)
{
	struct completion *cop = (struct completion *) arg;
	complete(cop);
}

/*
 * Clear initial stalls.
 */
static int ub_probe_clear_stall(struct ub_dev *sc, int stalled_pipe)
{
	int endp;
	struct usb_ctrlrequest *cr;
	struct completion compl;
	struct timer_list timer;
	int rc;

	init_completion(&compl);

	endp = usb_pipeendpoint(stalled_pipe);
	if (usb_pipein (stalled_pipe))
		endp |= USB_DIR_IN;

	cr = &sc->work_cr;
	cr->bRequestType = USB_RECIP_ENDPOINT;
	cr->bRequest = USB_REQ_CLEAR_FEATURE;
	cr->wValue = cpu_to_le16(USB_ENDPOINT_HALT);
	cr->wIndex = cpu_to_le16(endp);
	cr->wLength = cpu_to_le16(0);

	usb_fill_control_urb(&sc->work_urb, sc->dev, sc->send_ctrl_pipe,
	    (unsigned char*) cr, NULL, 0, ub_probe_urb_complete, &compl);
	sc->work_urb.transfer_flags = 0;
	sc->work_urb.actual_length = 0;
	sc->work_urb.error_count = 0;
	sc->work_urb.status = 0;

	init_timer(&timer);
	timer.function = ub_probe_timeout;
	timer.data = (unsigned long) &compl;
	timer.expires = jiffies + UB_CTRL_TIMEOUT;
	add_timer(&timer);

	if ((rc = usb_submit_urb(&sc->work_urb, GFP_KERNEL)) != 0) {
		printk(KERN_WARNING
		     "%s: Unable to submit a probe clear (%d)\n", sc->name, rc);
		del_timer_sync(&timer);
		return rc;
	}

	wait_for_completion(&compl);

	del_timer_sync(&timer);
	/*
	 * Most of the time, URB was done and dev set to NULL, and so
	 * the unlink bounces out with ENODEV. We do not call usb_kill_urb
	 * because we still think about a backport to 2.4.
	 */
	usb_unlink_urb(&sc->work_urb);

	/* reset the endpoint toggle */
	usb_settoggle(sc->dev, endp, usb_pipeout(sc->last_pipe), 0);

	return 0;
}

/*
 * Get the pipe settings.
 */
static int ub_get_pipes(struct ub_dev *sc, struct usb_device *dev,
    struct usb_interface *intf)
{
	struct usb_host_interface *altsetting = intf->cur_altsetting;
	struct usb_endpoint_descriptor *ep_in = NULL;
	struct usb_endpoint_descriptor *ep_out = NULL;
	struct usb_endpoint_descriptor *ep;
	int i;

	/*
	 * Find the endpoints we need.
	 * We are expecting a minimum of 2 endpoints - in and out (bulk).
	 * We will ignore any others.
	 */
	for (i = 0; i < altsetting->desc.bNumEndpoints; i++) {
		ep = &altsetting->endpoint[i].desc;

		/* Is it a BULK endpoint? */
		if ((ep->bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
				== USB_ENDPOINT_XFER_BULK) {
			/* BULK in or out? */
			if (ep->bEndpointAddress & USB_DIR_IN)
				ep_in = ep;
			else
				ep_out = ep;
		}
	}

	if (ep_in == NULL || ep_out == NULL) {
		printk(KERN_NOTICE "%s: device %u failed endpoint check\n",
		    sc->name, sc->dev->devnum);
		return -EIO;
	}

	/* Calculate and store the pipe values */
	sc->send_ctrl_pipe = usb_sndctrlpipe(dev, 0);
	sc->recv_ctrl_pipe = usb_rcvctrlpipe(dev, 0);
	sc->send_bulk_pipe = usb_sndbulkpipe(dev,
		ep_out->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);
	sc->recv_bulk_pipe = usb_rcvbulkpipe(dev, 
		ep_in->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK);

	return 0;
}

/*
 * Probing is done in the process context, which allows us to cheat
 * and not to build a state machine for the discovery.
 */
static int ub_probe(struct usb_interface *intf,
    const struct usb_device_id *dev_id)
{
	struct ub_dev *sc;
	request_queue_t *q;
	struct gendisk *disk;
	int rc;

	rc = -ENOMEM;
	if ((sc = kmalloc(sizeof(struct ub_dev), GFP_KERNEL)) == NULL)
		goto err_core;
	memset(sc, 0, sizeof(struct ub_dev));
	spin_lock_init(&sc->lock);
	usb_init_urb(&sc->work_urb);
	tasklet_init(&sc->tasklet, ub_scsi_action, (unsigned long)sc);
	atomic_set(&sc->poison, 0);

	init_timer(&sc->work_timer);
	sc->work_timer.data = (unsigned long) sc;
	sc->work_timer.function = ub_urb_timeout;

	ub_init_completion(&sc->work_done);
	sc->work_done.done = 1;		/* A little yuk, but oh well... */

	rc = -ENOSR;
	if ((sc->id = ub_id_get()) == -1)
		goto err_id;
	snprintf(sc->name, 8, DRV_NAME "%c", sc->id + 'a');

	sc->dev = interface_to_usbdev(intf);
	sc->intf = intf;
	// sc->ifnum = intf->cur_altsetting->desc.bInterfaceNumber;

	usb_set_intfdata(intf, sc);
	usb_get_dev(sc->dev);
	// usb_get_intf(sc->intf);	/* Do we need this? */

	/* XXX Verify that we can handle the device (from descriptors) */

	ub_get_pipes(sc, sc->dev, intf);

	if (device_create_file(&sc->intf->dev, &dev_attr_diag) != 0)
		goto err_diag;

	/*
	 * At this point, all USB initialization is done, do upper layer.
	 * We really hate halfway initialized structures, so from the
	 * invariants perspective, this ub_dev is fully constructed at
	 * this point.
	 */

	/*
	 * This is needed to clear toggles. It is a problem only if we do
	 * `rmmod ub && modprobe ub` without disconnects, but we like that.
	 */
	ub_probe_clear_stall(sc, sc->recv_bulk_pipe);
	ub_probe_clear_stall(sc, sc->send_bulk_pipe);

	/*
	 * The way this is used by the startup code is a little specific.
	 * A SCSI check causes a USB stall. Our common case code sees it
	 * and clears the check, after which the device is ready for use.
	 * But if a check was not present, any command other than
	 * TEST_UNIT_READY ends with a lockup (including REQUEST_SENSE).
	 *
	 * If we neglect to clear the SCSI check, the first real command fails
	 * (which is the capacity readout). We clear that and retry, but why
	 * causing spurious retries for no reason.
	 *
	 * Revalidation may start with its own TEST_UNIT_READY, but that one
	 * has to succeed, so we clear checks with an additional one here.
	 * In any case it's not our business how revaliadation is implemented.
	 */
	ub_sync_tur(sc);

	sc->removable = 1;		/* XXX Query this from the device */

	ub_revalidate(sc);
	/* This is pretty much a long term P3 */
	printk(KERN_INFO "%s: device %u capacity nsec %ld bsize %u\n",
	    sc->name, sc->dev->devnum, sc->capacity.nsec, sc->capacity.bsize);

	/*
	 * Just one disk per sc currently, but maybe more.
	 */
	rc = -ENOMEM;
	if ((disk = alloc_disk(UB_MINORS_PER_MAJOR)) == NULL)
		goto err_diskalloc;

	sc->disk = disk;
	sprintf(disk->disk_name, DRV_NAME "%c", sc->id + 'a');
	sprintf(disk->devfs_name, DEVFS_NAME "/%c", sc->id + 'a');
	disk->major = UB_MAJOR;
	disk->first_minor = sc->id * UB_MINORS_PER_MAJOR;
	disk->fops = &ub_bd_fops;
	disk->private_data = sc;
	disk->driverfs_dev = &intf->dev;

	rc = -ENOMEM;
	if ((q = blk_init_queue(ub_bd_rq_fn, &sc->lock)) == NULL)
		goto err_blkqinit;

	disk->queue = q;

        // blk_queue_bounce_limit(q, hba[i]->pdev->dma_mask);
	blk_queue_max_hw_segments(q, UB_MAX_REQ_SG);
	blk_queue_max_phys_segments(q, UB_MAX_REQ_SG);
	// blk_queue_segment_boundary(q, CARM_SG_BOUNDARY);
	blk_queue_max_sectors(q, UB_MAX_SECTORS);
	// blk_queue_hardsect_size(q, xxxxx);

	/*
	 * This is a serious infraction, caused by a deficiency in the
	 * USB sg interface (usb_sg_wait()). We plan to remove this once
	 * we get mileage on the driver and can justify a change to USB API.
	 * See blk_queue_bounce_limit() to understand this part.
	 *
	 * XXX And I still need to be aware of the DMA mask in the HC.
	 */
	q->bounce_pfn = blk_max_low_pfn;
	q->bounce_gfp = GFP_NOIO;

	q->queuedata = sc;

	set_capacity(disk, sc->capacity.nsec);
	if (sc->removable)
		disk->flags |= GENHD_FL_REMOVABLE;

	add_disk(disk);

	return 0;

err_blkqinit:
	put_disk(disk);
err_diskalloc:
	device_remove_file(&sc->intf->dev, &dev_attr_diag);
err_diag:
	usb_set_intfdata(intf, NULL);
	// usb_put_intf(sc->intf);
	usb_put_dev(sc->dev);
	spin_lock_irq(&ub_lock);
	ub_id_put(sc->id);
	spin_unlock_irq(&ub_lock);
err_id:
	kfree(sc);
err_core:
	return rc;
}

static void ub_disconnect(struct usb_interface *intf)
{
	struct ub_dev *sc = usb_get_intfdata(intf);
	struct gendisk *disk = sc->disk;
	request_queue_t *q = disk->queue;
	unsigned long flags;

	/*
	 * Fence stall clearnings, operations triggered by unlinkings and so on.
	 * We do not attempt to unlink any URBs, because we do not trust the
	 * unlink paths in HC drivers. Also, we get -84 upon disconnect anyway.
	 */
	atomic_set(&sc->poison, 1);

	/*
	 * Blow away queued commands.
	 *
	 * Actually, this never works, because before we get here
	 * the HCD terminates outstanding URB(s). It causes our
	 * SCSI command queue to advance, commands fail to submit,
	 * and the whole queue drains. So, we just use this code to
	 * print warnings.
	 */
	spin_lock_irqsave(&sc->lock, flags);
	{
		struct ub_scsi_cmd *cmd;
		int cnt = 0;
		while ((cmd = ub_cmdq_pop(sc)) != NULL) {
			cmd->error = -ENOTCONN;
			cmd->state = UB_CMDST_DONE;
			ub_cmdtr_state(sc, cmd);
			ub_cmdq_pop(sc);
			(*cmd->done)(sc, cmd);
			cnt++;
		}
		if (cnt != 0) {
			printk(KERN_WARNING "%s: "
			    "%d was queued after shutdown\n", sc->name, cnt);
		}
	}
	spin_unlock_irqrestore(&sc->lock, flags);

	/*
	 * Unregister the upper layer, this waits for all commands to end.
	 */
	if (disk->flags & GENHD_FL_UP)
		del_gendisk(disk);
	if (q)
		blk_cleanup_queue(q);

	/*
	 * If we zero disk->private_data BEFORE put_disk, we have to check
	 * for NULL all over the place in open, release, check_media and
	 * revalidate, because the block level semaphore is well inside the
	 * put_disk. But we cannot zero after the call, because *disk is gone.
	 * The sd.c is blatantly racy in this area.
	 */
	/* disk->private_data = NULL; */
	put_disk(disk);
	sc->disk = NULL;

	/*
	 * We really expect blk_cleanup_queue() to wait, so no amount
	 * of paranoya is too much.
	 *
	 * Taking a lock on a structure which is about to be freed
	 * is very nonsensual. Here it is largely a way to do a debug freeze,
	 * and a bracket which shows where the nonsensual code segment ends.
	 *
	 * Testing for -EINPROGRESS is always a bug, so we are bending
	 * the rules a little.
	 */
	spin_lock_irqsave(&sc->lock, flags);
	if (sc->work_urb.status == -EINPROGRESS) {	/* janitors: ignore */
		printk(KERN_WARNING "%s: "
		    "URB is active after disconnect\n", sc->name);
	}
	spin_unlock_irqrestore(&sc->lock, flags);

	/*
	 * At this point there must be no commands coming from anyone
	 * and no URBs left in transit.
	 */

	device_remove_file(&sc->intf->dev, &dev_attr_diag);
	usb_set_intfdata(intf, NULL);
	// usb_put_intf(sc->intf);
	sc->intf = NULL;
	usb_put_dev(sc->dev);
	sc->dev = NULL;

	spin_lock_irqsave(&ub_lock, flags);
	if (sc->openc == 0)
		ub_cleanup(sc);
	spin_unlock_irqrestore(&ub_lock, flags);
}

struct usb_driver ub_driver = {
	.owner =	THIS_MODULE,
	.name =		"ub",
	.probe =	ub_probe,
	.disconnect =	ub_disconnect,
	.id_table =	ub_usb_ids,
};

static int __init ub_init(void)
{
	int rc;

	/* P3 */ printk("ub: sizeof ub_scsi_cmd %zu ub_dev %zu\n",
			sizeof(struct ub_scsi_cmd), sizeof(struct ub_dev));

	if ((rc = register_blkdev(UB_MAJOR, DRV_NAME)) != 0)
		goto err_regblkdev;
	devfs_mk_dir(DEVFS_NAME);

	if ((rc = usb_register(&ub_driver)) != 0)
		goto err_register;

	return 0;

err_register:
	devfs_remove(DEVFS_NAME);
	unregister_blkdev(UB_MAJOR, DRV_NAME);
err_regblkdev:
	return rc;
}

static void __exit ub_exit(void)
{
	usb_deregister(&ub_driver);

	devfs_remove(DEVFS_NAME);
	unregister_blkdev(UB_MAJOR, DRV_NAME);
}

module_init(ub_init);
module_exit(ub_exit);

MODULE_LICENSE("GPL");