drivers/crypto/caam/jr.c - kernel/msm-4.9 - Gitiles

 /*
  * CAAM/SEC 4.x transport/backend driver
  * JobR backend functionality
  *
  * Copyright 2008-2012 Freescale Semiconductor, Inc.
  */

 #include <linux/of_irq.h>
 #include <linux/of_address.h>

 #include "compat.h"
 #include "regs.h"
 #include "jr.h"
 #include "desc.h"
 #include "intern.h"

 struct jr_driver_data {
 	/* List of Physical JobR's with the Driver */
 	struct list_head	jr_list;
 	spinlock_t		jr_alloc_lock;	/* jr_list lock */
 } ____cacheline_aligned;

 static struct jr_driver_data driver_data;

 static int caam_reset_hw_jr(struct device *dev)
 {
 	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
 	unsigned int timeout = 100000;

 	/*
 	 * mask interrupts since we are going to poll
 	 * for reset completion status
 	 */
 	setbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK);

 	/* initiate flush (required prior to reset) */
 	wr_reg32(&jrp->rregs->jrcommand, JRCR_RESET);
 	while (((rd_reg32(&jrp->rregs->jrintstatus) & JRINT_ERR_HALT_MASK) ==
 		JRINT_ERR_HALT_INPROGRESS) && --timeout)
 		cpu_relax();

 	if ((rd_reg32(&jrp->rregs->jrintstatus) & JRINT_ERR_HALT_MASK) !=
 	    JRINT_ERR_HALT_COMPLETE || timeout == 0) {
 		dev_err(dev, "failed to flush job ring %d\n", jrp->ridx);
 		return -EIO;
 	}

 	/* initiate reset */
 	timeout = 100000;
 	wr_reg32(&jrp->rregs->jrcommand, JRCR_RESET);
 	while ((rd_reg32(&jrp->rregs->jrcommand) & JRCR_RESET) && --timeout)
 		cpu_relax();

 	if (timeout == 0) {
 		dev_err(dev, "failed to reset job ring %d\n", jrp->ridx);
 		return -EIO;
 	}

 	/* unmask interrupts */
 	clrbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK);

 	return 0;
 }

 /*
  * Shutdown JobR independent of platform property code
  */
 int caam_jr_shutdown(struct device *dev)
 {
 	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
 	dma_addr_t inpbusaddr, outbusaddr;
 	int ret;

 	ret = caam_reset_hw_jr(dev);

 	tasklet_kill(&jrp->irqtask);

 	/* Release interrupt */
 	free_irq(jrp->irq, dev);

 	/* Free rings */
 	inpbusaddr = rd_reg64(&jrp->rregs->inpring_base);
 	outbusaddr = rd_reg64(&jrp->rregs->outring_base);
 	dma_free_coherent(dev, sizeof(dma_addr_t) * JOBR_DEPTH,
 			  jrp->inpring, inpbusaddr);
 	dma_free_coherent(dev, sizeof(struct jr_outentry) * JOBR_DEPTH,
 			  jrp->outring, outbusaddr);
 	kfree(jrp->entinfo);

 	return ret;
 }

 static int caam_jr_remove(struct platform_device *pdev)
 {
 	int ret;
 	struct device *jrdev;
 	struct caam_drv_private_jr *jrpriv;

 	jrdev = &pdev->dev;
 	jrpriv = dev_get_drvdata(jrdev);

 	/*
 	 * Return EBUSY if job ring already allocated.
 	 */
 	if (atomic_read(&jrpriv->tfm_count)) {
 		dev_err(jrdev, "Device is busy\n");
 		return -EBUSY;
 	}

 	/* Remove the node from Physical JobR list maintained by driver */
 	spin_lock(&driver_data.jr_alloc_lock);
 	list_del(&jrpriv->list_node);
 	spin_unlock(&driver_data.jr_alloc_lock);

 	/* Release ring */
 	ret = caam_jr_shutdown(jrdev);
 	if (ret)
 		dev_err(jrdev, "Failed to shut down job ring\n");
 	irq_dispose_mapping(jrpriv->irq);

 	return ret;
 }

 /* Main per-ring interrupt handler */
 static irqreturn_t caam_jr_interrupt(int irq, void *st_dev)
 {
 	struct device *dev = st_dev;
 	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
 	u32 irqstate;

 	/*
 	 * Check the output ring for ready responses, kick
 	 * tasklet if jobs done.
 	 */
 	irqstate = rd_reg32(&jrp->rregs->jrintstatus);
 	if (!irqstate)
 		return IRQ_NONE;

 	/*
 	 * If JobR error, we got more development work to do
 	 * Flag a bug now, but we really need to shut down and
 	 * restart the queue (and fix code).
 	 */
 	if (irqstate & JRINT_JR_ERROR) {
 		dev_err(dev, "job ring error: irqstate: %08x\n", irqstate);
 		BUG();
 	}

 	/* mask valid interrupts */
 	setbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK);

 	/* Have valid interrupt at this point, just ACK and trigger */
 	wr_reg32(&jrp->rregs->jrintstatus, irqstate);

 	preempt_disable();
 	tasklet_schedule(&jrp->irqtask);
 	preempt_enable();

 	return IRQ_HANDLED;
 }

 /* Deferred service handler, run as interrupt-fired tasklet */
 static void caam_jr_dequeue(unsigned long devarg)
 {
 	int hw_idx, sw_idx, i, head, tail;
 	struct device *dev = (struct device *)devarg;
 	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
 	void (*usercall)(struct device *dev, u32 *desc, u32 status, void *arg);
 	u32 *userdesc, userstatus;
 	void *userarg;

 	while (rd_reg32(&jrp->rregs->outring_used)) {

 		head = ACCESS_ONCE(jrp->head);

 		spin_lock(&jrp->outlock);

 		sw_idx = tail = jrp->tail;
 		hw_idx = jrp->out_ring_read_index;

 		for (i = 0; CIRC_CNT(head, tail + i, JOBR_DEPTH) >= 1; i++) {
 			sw_idx = (tail + i) & (JOBR_DEPTH - 1);

 			smp_read_barrier_depends();

 			if (jrp->outring[hw_idx].desc ==
 			    jrp->entinfo[sw_idx].desc_addr_dma)
 				break; /* found */
 		}
 		/* we should never fail to find a matching descriptor */
 		BUG_ON(CIRC_CNT(head, tail + i, JOBR_DEPTH) <= 0);

 		/* Unmap just-run descriptor so we can post-process */
 		dma_unmap_single(dev, jrp->outring[hw_idx].desc,
 				 jrp->entinfo[sw_idx].desc_size,
 				 DMA_TO_DEVICE);

 		/* mark completed, avoid matching on a recycled desc addr */
 		jrp->entinfo[sw_idx].desc_addr_dma = 0;

 		/* Stash callback params for use outside of lock */
 		usercall = jrp->entinfo[sw_idx].callbk;
 		userarg = jrp->entinfo[sw_idx].cbkarg;
 		userdesc = jrp->entinfo[sw_idx].desc_addr_virt;
 		userstatus = jrp->outring[hw_idx].jrstatus;

 		/* set done */
 		wr_reg32(&jrp->rregs->outring_rmvd, 1);

 		jrp->out_ring_read_index = (jrp->out_ring_read_index + 1) &
 					   (JOBR_DEPTH - 1);

 		/*
 		 * if this job completed out-of-order, do not increment
 		 * the tail.  Otherwise, increment tail by 1 plus the
 		 * number of subsequent jobs already completed out-of-order
 		 */
 		if (sw_idx == tail) {
 			do {
 				tail = (tail + 1) & (JOBR_DEPTH - 1);
 				smp_read_barrier_depends();
 			} while (CIRC_CNT(head, tail, JOBR_DEPTH) >= 1 &&
 				 jrp->entinfo[tail].desc_addr_dma == 0);

 			jrp->tail = tail;
 		}

 		spin_unlock(&jrp->outlock);

 		/* Finally, execute user's callback */
 		usercall(dev, userdesc, userstatus, userarg);
 	}

 	/* reenable / unmask IRQs */
 	clrbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK);
 }

 /**
  * caam_jr_alloc() - Alloc a job ring for someone to use as needed.
  *
  * returns :  pointer to the newly allocated physical
  *	      JobR dev can be written to if successful.
  **/
 struct device *caam_jr_alloc(void)
 {
 	struct caam_drv_private_jr *jrpriv, *min_jrpriv = NULL;
 	struct device *dev = NULL;
 	int min_tfm_cnt	= INT_MAX;
 	int tfm_cnt;

 	spin_lock(&driver_data.jr_alloc_lock);

 	if (list_empty(&driver_data.jr_list)) {
 		spin_unlock(&driver_data.jr_alloc_lock);
 		return ERR_PTR(-ENODEV);
 	}

 	list_for_each_entry(jrpriv, &driver_data.jr_list, list_node) {
 		tfm_cnt = atomic_read(&jrpriv->tfm_count);
 		if (tfm_cnt < min_tfm_cnt) {
 			min_tfm_cnt = tfm_cnt;
 			min_jrpriv = jrpriv;
 		}
 		if (!min_tfm_cnt)
 			break;
 	}

 	if (min_jrpriv) {
 		atomic_inc(&min_jrpriv->tfm_count);
 		dev = min_jrpriv->dev;
 	}
 	spin_unlock(&driver_data.jr_alloc_lock);

 	return dev;
 }
 EXPORT_SYMBOL(caam_jr_alloc);

 /**
  * caam_jr_free() - Free the Job Ring
  * @rdev     - points to the dev that identifies the Job ring to
  *             be released.
  **/
 void caam_jr_free(struct device *rdev)
 {
 	struct caam_drv_private_jr *jrpriv = dev_get_drvdata(rdev);

 	atomic_dec(&jrpriv->tfm_count);
 }
 EXPORT_SYMBOL(caam_jr_free);

 /**
  * caam_jr_enqueue() - Enqueue a job descriptor head. Returns 0 if OK,
  * -EBUSY if the queue is full, -EIO if it cannot map the caller's
  * descriptor.
  * @dev:  device of the job ring to be used. This device should have
  *        been assigned prior by caam_jr_register().
  * @desc: points to a job descriptor that execute our request. All
  *        descriptors (and all referenced data) must be in a DMAable
  *        region, and all data references must be physical addresses
  *        accessible to CAAM (i.e. within a PAMU window granted
  *        to it).
  * @cbk:  pointer to a callback function to be invoked upon completion
  *        of this request. This has the form:
  *        callback(struct device *dev, u32 *desc, u32 stat, void *arg)
  *        where:
  *        @dev:    contains the job ring device that processed this
  *                 response.
  *        @desc:   descriptor that initiated the request, same as
  *                 "desc" being argued to caam_jr_enqueue().
  *        @status: untranslated status received from CAAM. See the
  *                 reference manual for a detailed description of
  *                 error meaning, or see the JRSTA definitions in the
  *                 register header file
  *        @areq:   optional pointer to an argument passed with the
  *                 original request
  * @areq: optional pointer to a user argument for use at callback
  *        time.
  **/
 int caam_jr_enqueue(struct device *dev, u32 *desc,
 		    void (*cbk)(struct device *dev, u32 *desc,
 				u32 status, void *areq),
 		    void *areq)
 {
 	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
 	struct caam_jrentry_info *head_entry;
 	int head, tail, desc_size;
 	dma_addr_t desc_dma;

 	desc_size = (*desc & HDR_JD_LENGTH_MASK) * sizeof(u32);
 	desc_dma = dma_map_single(dev, desc, desc_size, DMA_TO_DEVICE);
 	if (dma_mapping_error(dev, desc_dma)) {
 		dev_err(dev, "caam_jr_enqueue(): can't map jobdesc\n");
 		return -EIO;
 	}

 	spin_lock_bh(&jrp->inplock);

 	head = jrp->head;
 	tail = ACCESS_ONCE(jrp->tail);

 	if (!rd_reg32(&jrp->rregs->inpring_avail) ||
 	    CIRC_SPACE(head, tail, JOBR_DEPTH) <= 0) {
 		spin_unlock_bh(&jrp->inplock);
 		dma_unmap_single(dev, desc_dma, desc_size, DMA_TO_DEVICE);
 		return -EBUSY;
 	}

 	head_entry = &jrp->entinfo[head];
 	head_entry->desc_addr_virt = desc;
 	head_entry->desc_size = desc_size;
 	head_entry->callbk = (void *)cbk;
 	head_entry->cbkarg = areq;
 	head_entry->desc_addr_dma = desc_dma;

 	jrp->inpring[jrp->inp_ring_write_index] = desc_dma;

 	smp_wmb();

 	jrp->inp_ring_write_index = (jrp->inp_ring_write_index + 1) &
 				    (JOBR_DEPTH - 1);
 	jrp->head = (head + 1) & (JOBR_DEPTH - 1);

 	wr_reg32(&jrp->rregs->inpring_jobadd, 1);

 	spin_unlock_bh(&jrp->inplock);

 	return 0;
 }
 EXPORT_SYMBOL(caam_jr_enqueue);

 /*
  * Init JobR independent of platform property detection
  */
 static int caam_jr_init(struct device *dev)
 {
 	struct caam_drv_private_jr *jrp;
 	dma_addr_t inpbusaddr, outbusaddr;
 	int i, error;

 	jrp = dev_get_drvdata(dev);

 	tasklet_init(&jrp->irqtask, caam_jr_dequeue, (unsigned long)dev);

 	/* Connect job ring interrupt handler. */
 	error = request_irq(jrp->irq, caam_jr_interrupt, IRQF_SHARED,
 			    dev_name(dev), dev);
 	if (error) {
 		dev_err(dev, "can't connect JobR %d interrupt (%d)\n",
 			jrp->ridx, jrp->irq);
 		irq_dispose_mapping(jrp->irq);
 		jrp->irq = 0;
 		return -EINVAL;
 	}

 	error = caam_reset_hw_jr(dev);
 	if (error)
 		return error;

 	jrp->inpring = dma_alloc_coherent(dev, sizeof(dma_addr_t) * JOBR_DEPTH,
 					  &inpbusaddr, GFP_KERNEL);

 	jrp->outring = dma_alloc_coherent(dev, sizeof(struct jr_outentry) *
 					  JOBR_DEPTH, &outbusaddr, GFP_KERNEL);

 	jrp->entinfo = kzalloc(sizeof(struct caam_jrentry_info) * JOBR_DEPTH,
 			       GFP_KERNEL);

 	if ((jrp->inpring == NULL) || (jrp->outring == NULL) ||
 	    (jrp->entinfo == NULL)) {
 		dev_err(dev, "can't allocate job rings for %d\n",
 			jrp->ridx);
 		return -ENOMEM;
 	}

 	for (i = 0; i < JOBR_DEPTH; i++)
 		jrp->entinfo[i].desc_addr_dma = !0;

 	/* Setup rings */
 	jrp->inp_ring_write_index = 0;
 	jrp->out_ring_read_index = 0;
 	jrp->head = 0;
 	jrp->tail = 0;

 	wr_reg64(&jrp->rregs->inpring_base, inpbusaddr);
 	wr_reg64(&jrp->rregs->outring_base, outbusaddr);
 	wr_reg32(&jrp->rregs->inpring_size, JOBR_DEPTH);
 	wr_reg32(&jrp->rregs->outring_size, JOBR_DEPTH);

 	jrp->ringsize = JOBR_DEPTH;

 	spin_lock_init(&jrp->inplock);
 	spin_lock_init(&jrp->outlock);

 	/* Select interrupt coalescing parameters */
 	setbits32(&jrp->rregs->rconfig_lo, JOBR_INTC |
 		  (JOBR_INTC_COUNT_THLD << JRCFG_ICDCT_SHIFT) |
 		  (JOBR_INTC_TIME_THLD << JRCFG_ICTT_SHIFT));

 	return 0;
 }


 /*
  * Probe routine for each detected JobR subsystem.
  */
 static int caam_jr_probe(struct platform_device *pdev)
 {
 	struct device *jrdev;
 	struct device_node *nprop;
 	struct caam_job_ring __iomem *ctrl;
 	struct caam_drv_private_jr *jrpriv;
 	static int total_jobrs;
 	int error;

 	jrdev = &pdev->dev;
 	jrpriv = devm_kmalloc(jrdev, sizeof(struct caam_drv_private_jr),
 			      GFP_KERNEL);
 	if (!jrpriv)
 		return -ENOMEM;

 	dev_set_drvdata(jrdev, jrpriv);

 	/* save ring identity relative to detection */
 	jrpriv->ridx = total_jobrs++;

 	nprop = pdev->dev.of_node;
 	/* Get configuration properties from device tree */
 	/* First, get register page */
 	ctrl = of_iomap(nprop, 0);
 	if (!ctrl) {
 		dev_err(jrdev, "of_iomap() failed\n");
 		return -ENOMEM;
 	}

 	jrpriv->rregs = (struct caam_job_ring __force *)ctrl;

 	if (sizeof(dma_addr_t) == sizeof(u64))
 		if (of_device_is_compatible(nprop, "fsl,sec-v5.0-job-ring"))
 			dma_set_mask_and_coherent(jrdev, DMA_BIT_MASK(40));
 		else
 			dma_set_mask_and_coherent(jrdev, DMA_BIT_MASK(36));
 	else
 		dma_set_mask_and_coherent(jrdev, DMA_BIT_MASK(32));

 	/* Identify the interrupt */
 	jrpriv->irq = irq_of_parse_and_map(nprop, 0);

 	/* Now do the platform independent part */
 	error = caam_jr_init(jrdev); /* now turn on hardware */
 	if (error)
 		return error;

 	jrpriv->dev = jrdev;
 	spin_lock(&driver_data.jr_alloc_lock);
 	list_add_tail(&jrpriv->list_node, &driver_data.jr_list);
 	spin_unlock(&driver_data.jr_alloc_lock);

 	atomic_set(&jrpriv->tfm_count, 0);

 	return 0;
 }

 static struct of_device_id caam_jr_match[] = {
 	{
 		.compatible = "fsl,sec-v4.0-job-ring",
 	},
 	{
 		.compatible = "fsl,sec4.0-job-ring",
 	},
 	{},
 };
 MODULE_DEVICE_TABLE(of, caam_jr_match);

 static struct platform_driver caam_jr_driver = {
 	.driver = {
 		.name = "caam_jr",
 		.owner = THIS_MODULE,
 		.of_match_table = caam_jr_match,
 	},
 	.probe       = caam_jr_probe,
 	.remove      = caam_jr_remove,
 };

 static int __init jr_driver_init(void)
 {
 	spin_lock_init(&driver_data.jr_alloc_lock);
 	INIT_LIST_HEAD(&driver_data.jr_list);
 	return platform_driver_register(&caam_jr_driver);
 }

 static void __exit jr_driver_exit(void)
 {
 	platform_driver_unregister(&caam_jr_driver);
 }

 module_init(jr_driver_init);
 module_exit(jr_driver_exit);

 MODULE_LICENSE("GPL");
 MODULE_DESCRIPTION("FSL CAAM JR request backend");
 MODULE_AUTHOR("Freescale Semiconductor - NMG/STC");
	/*
	* CAAM/SEC 4.x transport/backend driver
	* JobR backend functionality
	*
	* Copyright 2008-2012 Freescale Semiconductor, Inc.
	*/

	#include <linux/of_irq.h>
	#include <linux/of_address.h>

	#include "compat.h"
	#include "regs.h"
	#include "jr.h"
	#include "desc.h"
	#include "intern.h"

	struct jr_driver_data {
	/* List of Physical JobR's with the Driver */
	struct list_head jr_list;
	spinlock_t jr_alloc_lock; /* jr_list lock */
	} ____cacheline_aligned;

	static struct jr_driver_data driver_data;

	static int caam_reset_hw_jr(struct device *dev)
	{
	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
	unsigned int timeout = 100000;

	/*
	* mask interrupts since we are going to poll
	* for reset completion status
	*/
	setbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK);

	/* initiate flush (required prior to reset) */
	wr_reg32(&jrp->rregs->jrcommand, JRCR_RESET);
	while (((rd_reg32(&jrp->rregs->jrintstatus) & JRINT_ERR_HALT_MASK) ==
	JRINT_ERR_HALT_INPROGRESS) && --timeout)
	cpu_relax();

	if ((rd_reg32(&jrp->rregs->jrintstatus) & JRINT_ERR_HALT_MASK) !=
	JRINT_ERR_HALT_COMPLETE \|\| timeout == 0) {
	dev_err(dev, "failed to flush job ring %d\n", jrp->ridx);
	return -EIO;
	}

	/* initiate reset */
	timeout = 100000;
	wr_reg32(&jrp->rregs->jrcommand, JRCR_RESET);
	while ((rd_reg32(&jrp->rregs->jrcommand) & JRCR_RESET) && --timeout)
	cpu_relax();

	if (timeout == 0) {
	dev_err(dev, "failed to reset job ring %d\n", jrp->ridx);
	return -EIO;
	}

	/* unmask interrupts */
	clrbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK);

	return 0;
	}

	/*
	* Shutdown JobR independent of platform property code
	*/
	int caam_jr_shutdown(struct device *dev)
	{
	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
	dma_addr_t inpbusaddr, outbusaddr;
	int ret;

	ret = caam_reset_hw_jr(dev);

	tasklet_kill(&jrp->irqtask);

	/* Release interrupt */
	free_irq(jrp->irq, dev);

	/* Free rings */
	inpbusaddr = rd_reg64(&jrp->rregs->inpring_base);
	outbusaddr = rd_reg64(&jrp->rregs->outring_base);
	dma_free_coherent(dev, sizeof(dma_addr_t) * JOBR_DEPTH,
	jrp->inpring, inpbusaddr);
	dma_free_coherent(dev, sizeof(struct jr_outentry) * JOBR_DEPTH,
	jrp->outring, outbusaddr);
	kfree(jrp->entinfo);

	return ret;
	}

	static int caam_jr_remove(struct platform_device *pdev)
	{
	int ret;
	struct device *jrdev;
	struct caam_drv_private_jr *jrpriv;

	jrdev = &pdev->dev;
	jrpriv = dev_get_drvdata(jrdev);

	/*
	* Return EBUSY if job ring already allocated.
	*/
	if (atomic_read(&jrpriv->tfm_count)) {
	dev_err(jrdev, "Device is busy\n");
	return -EBUSY;
	}

	/* Remove the node from Physical JobR list maintained by driver */
	spin_lock(&driver_data.jr_alloc_lock);
	list_del(&jrpriv->list_node);
	spin_unlock(&driver_data.jr_alloc_lock);

	/* Release ring */
	ret = caam_jr_shutdown(jrdev);
	if (ret)
	dev_err(jrdev, "Failed to shut down job ring\n");
	irq_dispose_mapping(jrpriv->irq);

	return ret;
	}

	/* Main per-ring interrupt handler */
	static irqreturn_t caam_jr_interrupt(int irq, void *st_dev)
	{
	struct device *dev = st_dev;
	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
	u32 irqstate;

	/*
	* Check the output ring for ready responses, kick
	* tasklet if jobs done.
	*/
	irqstate = rd_reg32(&jrp->rregs->jrintstatus);
	if (!irqstate)
	return IRQ_NONE;

	/*
	* If JobR error, we got more development work to do
	* Flag a bug now, but we really need to shut down and
	* restart the queue (and fix code).
	*/
	if (irqstate & JRINT_JR_ERROR) {
	dev_err(dev, "job ring error: irqstate: %08x\n", irqstate);
	BUG();
	}

	/* mask valid interrupts */
	setbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK);

	/* Have valid interrupt at this point, just ACK and trigger */
	wr_reg32(&jrp->rregs->jrintstatus, irqstate);

	preempt_disable();
	tasklet_schedule(&jrp->irqtask);
	preempt_enable();

	return IRQ_HANDLED;
	}

	/* Deferred service handler, run as interrupt-fired tasklet */
	static void caam_jr_dequeue(unsigned long devarg)
	{
	int hw_idx, sw_idx, i, head, tail;
	struct device dev = (struct device )devarg;
	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
	void (usercall)(struct device dev, u32 desc, u32 status, void arg);
	u32 *userdesc, userstatus;
	void *userarg;

	while (rd_reg32(&jrp->rregs->outring_used)) {

	head = ACCESS_ONCE(jrp->head);

	spin_lock(&jrp->outlock);

	sw_idx = tail = jrp->tail;
	hw_idx = jrp->out_ring_read_index;

	for (i = 0; CIRC_CNT(head, tail + i, JOBR_DEPTH) >= 1; i++) {
	sw_idx = (tail + i) & (JOBR_DEPTH - 1);

	smp_read_barrier_depends();

	if (jrp->outring[hw_idx].desc ==
	jrp->entinfo[sw_idx].desc_addr_dma)
	break; /* found */
	}
	/* we should never fail to find a matching descriptor */
	BUG_ON(CIRC_CNT(head, tail + i, JOBR_DEPTH) <= 0);

	/* Unmap just-run descriptor so we can post-process */
	dma_unmap_single(dev, jrp->outring[hw_idx].desc,
	jrp->entinfo[sw_idx].desc_size,
	DMA_TO_DEVICE);

	/* mark completed, avoid matching on a recycled desc addr */
	jrp->entinfo[sw_idx].desc_addr_dma = 0;

	/* Stash callback params for use outside of lock */
	usercall = jrp->entinfo[sw_idx].callbk;
	userarg = jrp->entinfo[sw_idx].cbkarg;
	userdesc = jrp->entinfo[sw_idx].desc_addr_virt;
	userstatus = jrp->outring[hw_idx].jrstatus;

	/* set done */
	wr_reg32(&jrp->rregs->outring_rmvd, 1);

	jrp->out_ring_read_index = (jrp->out_ring_read_index + 1) &
	(JOBR_DEPTH - 1);

	/*
	* if this job completed out-of-order, do not increment
	* the tail. Otherwise, increment tail by 1 plus the
	* number of subsequent jobs already completed out-of-order
	*/
	if (sw_idx == tail) {
	do {
	tail = (tail + 1) & (JOBR_DEPTH - 1);
	smp_read_barrier_depends();
	} while (CIRC_CNT(head, tail, JOBR_DEPTH) >= 1 &&
	jrp->entinfo[tail].desc_addr_dma == 0);

	jrp->tail = tail;
	}

	spin_unlock(&jrp->outlock);

	/* Finally, execute user's callback */
	usercall(dev, userdesc, userstatus, userarg);
	}

	/* reenable / unmask IRQs */
	clrbits32(&jrp->rregs->rconfig_lo, JRCFG_IMSK);
	}

	/**
	* caam_jr_alloc() - Alloc a job ring for someone to use as needed.
	*
	* returns : pointer to the newly allocated physical
	* JobR dev can be written to if successful.
	**/
	struct device *caam_jr_alloc(void)
	{
	struct caam_drv_private_jr jrpriv, min_jrpriv = NULL;
	struct device *dev = NULL;
	int min_tfm_cnt = INT_MAX;
	int tfm_cnt;

	spin_lock(&driver_data.jr_alloc_lock);

	if (list_empty(&driver_data.jr_list)) {
	spin_unlock(&driver_data.jr_alloc_lock);
	return ERR_PTR(-ENODEV);
	}

	list_for_each_entry(jrpriv, &driver_data.jr_list, list_node) {
	tfm_cnt = atomic_read(&jrpriv->tfm_count);
	if (tfm_cnt < min_tfm_cnt) {
	min_tfm_cnt = tfm_cnt;
	min_jrpriv = jrpriv;
	}
	if (!min_tfm_cnt)
	break;
	}

	if (min_jrpriv) {
	atomic_inc(&min_jrpriv->tfm_count);
	dev = min_jrpriv->dev;
	}
	spin_unlock(&driver_data.jr_alloc_lock);

	return dev;
	}
	EXPORT_SYMBOL(caam_jr_alloc);

	/**
	* caam_jr_free() - Free the Job Ring
	* @rdev - points to the dev that identifies the Job ring to
	* be released.
	**/
	void caam_jr_free(struct device *rdev)
	{
	struct caam_drv_private_jr *jrpriv = dev_get_drvdata(rdev);

	atomic_dec(&jrpriv->tfm_count);
	}
	EXPORT_SYMBOL(caam_jr_free);

	/**
	* caam_jr_enqueue() - Enqueue a job descriptor head. Returns 0 if OK,
	* -EBUSY if the queue is full, -EIO if it cannot map the caller's
	* descriptor.
	* @dev: device of the job ring to be used. This device should have
	* been assigned prior by caam_jr_register().
	* @desc: points to a job descriptor that execute our request. All
	* descriptors (and all referenced data) must be in a DMAable
	* region, and all data references must be physical addresses
	* accessible to CAAM (i.e. within a PAMU window granted
	* to it).
	* @cbk: pointer to a callback function to be invoked upon completion
	* of this request. This has the form:
	* callback(struct device dev, u32 desc, u32 stat, void *arg)
	* where:
	* @dev: contains the job ring device that processed this
	* response.
	* @desc: descriptor that initiated the request, same as
	* "desc" being argued to caam_jr_enqueue().
	* @status: untranslated status received from CAAM. See the
	* reference manual for a detailed description of
	* error meaning, or see the JRSTA definitions in the
	* register header file
	* @areq: optional pointer to an argument passed with the
	* original request
	* @areq: optional pointer to a user argument for use at callback
	* time.
	**/
	int caam_jr_enqueue(struct device dev, u32 desc,
	void (cbk)(struct device dev, u32 *desc,
	u32 status, void *areq),
	void *areq)
	{
	struct caam_drv_private_jr *jrp = dev_get_drvdata(dev);
	struct caam_jrentry_info *head_entry;
	int head, tail, desc_size;
	dma_addr_t desc_dma;

	desc_size = (desc & HDR_JD_LENGTH_MASK) sizeof(u32);
	desc_dma = dma_map_single(dev, desc, desc_size, DMA_TO_DEVICE);
	if (dma_mapping_error(dev, desc_dma)) {
	dev_err(dev, "caam_jr_enqueue(): can't map jobdesc\n");
	return -EIO;
	}

	spin_lock_bh(&jrp->inplock);

	head = jrp->head;
	tail = ACCESS_ONCE(jrp->tail);

	if (!rd_reg32(&jrp->rregs->inpring_avail) \|\|
	CIRC_SPACE(head, tail, JOBR_DEPTH) <= 0) {
	spin_unlock_bh(&jrp->inplock);
	dma_unmap_single(dev, desc_dma, desc_size, DMA_TO_DEVICE);
	return -EBUSY;
	}

	head_entry = &jrp->entinfo[head];
	head_entry->desc_addr_virt = desc;
	head_entry->desc_size = desc_size;
	head_entry->callbk = (void *)cbk;
	head_entry->cbkarg = areq;
	head_entry->desc_addr_dma = desc_dma;

	jrp->inpring[jrp->inp_ring_write_index] = desc_dma;

	smp_wmb();

	jrp->inp_ring_write_index = (jrp->inp_ring_write_index + 1) &
	(JOBR_DEPTH - 1);
	jrp->head = (head + 1) & (JOBR_DEPTH - 1);

	wr_reg32(&jrp->rregs->inpring_jobadd, 1);

	spin_unlock_bh(&jrp->inplock);

	return 0;
	}
	EXPORT_SYMBOL(caam_jr_enqueue);

	/*
	* Init JobR independent of platform property detection
	*/
	static int caam_jr_init(struct device *dev)
	{
	struct caam_drv_private_jr *jrp;
	dma_addr_t inpbusaddr, outbusaddr;
	int i, error;

	jrp = dev_get_drvdata(dev);

	tasklet_init(&jrp->irqtask, caam_jr_dequeue, (unsigned long)dev);

	/* Connect job ring interrupt handler. */
	error = request_irq(jrp->irq, caam_jr_interrupt, IRQF_SHARED,
	dev_name(dev), dev);
	if (error) {
	dev_err(dev, "can't connect JobR %d interrupt (%d)\n",
	jrp->ridx, jrp->irq);
	irq_dispose_mapping(jrp->irq);
	jrp->irq = 0;
	return -EINVAL;
	}

	error = caam_reset_hw_jr(dev);
	if (error)
	return error;

	jrp->inpring = dma_alloc_coherent(dev, sizeof(dma_addr_t) * JOBR_DEPTH,
	&inpbusaddr, GFP_KERNEL);

	jrp->outring = dma_alloc_coherent(dev, sizeof(struct jr_outentry) *
	JOBR_DEPTH, &outbusaddr, GFP_KERNEL);

	jrp->entinfo = kzalloc(sizeof(struct caam_jrentry_info) * JOBR_DEPTH,
	GFP_KERNEL);

	if ((jrp->inpring == NULL) \|\| (jrp->outring == NULL) \|\|
	(jrp->entinfo == NULL)) {
	dev_err(dev, "can't allocate job rings for %d\n",
	jrp->ridx);
	return -ENOMEM;
	}

	for (i = 0; i < JOBR_DEPTH; i++)
	jrp->entinfo[i].desc_addr_dma = !0;

	/* Setup rings */
	jrp->inp_ring_write_index = 0;
	jrp->out_ring_read_index = 0;
	jrp->head = 0;
	jrp->tail = 0;

	wr_reg64(&jrp->rregs->inpring_base, inpbusaddr);
	wr_reg64(&jrp->rregs->outring_base, outbusaddr);
	wr_reg32(&jrp->rregs->inpring_size, JOBR_DEPTH);
	wr_reg32(&jrp->rregs->outring_size, JOBR_DEPTH);

	jrp->ringsize = JOBR_DEPTH;

	spin_lock_init(&jrp->inplock);
	spin_lock_init(&jrp->outlock);

	/* Select interrupt coalescing parameters */
	setbits32(&jrp->rregs->rconfig_lo, JOBR_INTC \|
	(JOBR_INTC_COUNT_THLD << JRCFG_ICDCT_SHIFT) \|
	(JOBR_INTC_TIME_THLD << JRCFG_ICTT_SHIFT));

	return 0;
	}


	/*
	* Probe routine for each detected JobR subsystem.
	*/
	static int caam_jr_probe(struct platform_device *pdev)
	{
	struct device *jrdev;
	struct device_node *nprop;
	struct caam_job_ring __iomem *ctrl;
	struct caam_drv_private_jr *jrpriv;
	static int total_jobrs;
	int error;

	jrdev = &pdev->dev;
	jrpriv = devm_kmalloc(jrdev, sizeof(struct caam_drv_private_jr),
	GFP_KERNEL);
	if (!jrpriv)
	return -ENOMEM;

	dev_set_drvdata(jrdev, jrpriv);

	/* save ring identity relative to detection */
	jrpriv->ridx = total_jobrs++;

	nprop = pdev->dev.of_node;
	/* Get configuration properties from device tree */
	/* First, get register page */
	ctrl = of_iomap(nprop, 0);
	if (!ctrl) {
	dev_err(jrdev, "of_iomap() failed\n");
	return -ENOMEM;
	}

	jrpriv->rregs = (struct caam_job_ring __force *)ctrl;

	if (sizeof(dma_addr_t) == sizeof(u64))
	if (of_device_is_compatible(nprop, "fsl,sec-v5.0-job-ring"))
	dma_set_mask_and_coherent(jrdev, DMA_BIT_MASK(40));
	else
	dma_set_mask_and_coherent(jrdev, DMA_BIT_MASK(36));
	else
	dma_set_mask_and_coherent(jrdev, DMA_BIT_MASK(32));

	/* Identify the interrupt */
	jrpriv->irq = irq_of_parse_and_map(nprop, 0);

	/* Now do the platform independent part */
	error = caam_jr_init(jrdev); /* now turn on hardware */
	if (error)
	return error;

	jrpriv->dev = jrdev;
	spin_lock(&driver_data.jr_alloc_lock);
	list_add_tail(&jrpriv->list_node, &driver_data.jr_list);
	spin_unlock(&driver_data.jr_alloc_lock);

	atomic_set(&jrpriv->tfm_count, 0);

	return 0;
	}

	static struct of_device_id caam_jr_match[] = {
	{
	.compatible = "fsl,sec-v4.0-job-ring",
	},
	{
	.compatible = "fsl,sec4.0-job-ring",
	},
	{},
	};
	MODULE_DEVICE_TABLE(of, caam_jr_match);

	static struct platform_driver caam_jr_driver = {
	.driver = {
	.name = "caam_jr",
	.owner = THIS_MODULE,
	.of_match_table = caam_jr_match,
	},
	.probe = caam_jr_probe,
	.remove = caam_jr_remove,
	};

	static int __init jr_driver_init(void)
	{
	spin_lock_init(&driver_data.jr_alloc_lock);
	INIT_LIST_HEAD(&driver_data.jr_list);
	return platform_driver_register(&caam_jr_driver);
	}

	static void __exit jr_driver_exit(void)
	{
	platform_driver_unregister(&caam_jr_driver);
	}

	module_init(jr_driver_init);
	module_exit(jr_driver_exit);

	MODULE_LICENSE("GPL");
	MODULE_DESCRIPTION("FSL CAAM JR request backend");
	MODULE_AUTHOR("Freescale Semiconductor - NMG/STC");