/*
 * 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);

                        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);
                        } 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);
                goto out_kill_deq;
        }

        error = caam_reset_hw_jr(dev);
        if (error)
                goto out_free_irq;

        error = -ENOMEM;
        jrp->inpring = dma_alloc_coherent(dev, sizeof(dma_addr_t) * JOBR_DEPTH,
                                          &inpbusaddr, GFP_KERNEL);
        if (!jrp->inpring)
                goto out_free_irq;

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

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

        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;

out_free_outring:
        dma_free_coherent(dev, sizeof(struct jr_outentry) * JOBR_DEPTH,
                          jrp->outring, outbusaddr);
out_free_inpring:
        dma_free_coherent(dev, sizeof(dma_addr_t) * JOBR_DEPTH,
                          jrp->inpring, inpbusaddr);
        dev_err(dev, "can't allocate job rings for %d\n", jrp->ridx);
out_free_irq:
        free_irq(jrp->irq, dev);
out_kill_deq:
        tasklet_kill(&jrp->irqtask);
        return error;
}


/*
 * 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) {
                irq_dispose_mapping(jrpriv->irq);
                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",
                .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");