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[linux-2.6/btrfs-unstable.git] / drivers / dma / omap-dma.c

/*
 * OMAP DMAengine support
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/dmaengine.h>
#include <linux/dma-mapping.h>
#include <linux/err.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/list.h>
#include <linux/module.h>
#include <linux/omap-dma.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/spinlock.h>

#include "virt-dma.h"

#include <plat/cpu.h>
#include <plat/dma.h>

struct omap_dmadev {
        struct dma_device ddev;
        spinlock_t lock;
        struct tasklet_struct task;
        struct list_head pending;
};

struct omap_chan {
        struct virt_dma_chan vc;
        struct list_head node;

        struct dma_slave_config cfg;
        unsigned dma_sig;
        bool cyclic;
        bool paused;

        int dma_ch;
        struct omap_desc *desc;
        unsigned sgidx;
};

struct omap_sg {
        dma_addr_t addr;
        uint32_t en;            /* number of elements (24-bit) */
        uint32_t fn;            /* number of frames (16-bit) */
};

struct omap_desc {
        struct virt_dma_desc vd;
        enum dma_transfer_direction dir;
        dma_addr_t dev_addr;

        int16_t fi;             /* for OMAP_DMA_SYNC_PACKET */
        uint8_t es;             /* OMAP_DMA_DATA_TYPE_xxx */
        uint8_t sync_mode;      /* OMAP_DMA_SYNC_xxx */
        uint8_t sync_type;      /* OMAP_DMA_xxx_SYNC* */
        uint8_t periph_port;    /* Peripheral port */

        unsigned sglen;
        struct omap_sg sg[0];
};

static const unsigned es_bytes[] = {
        [OMAP_DMA_DATA_TYPE_S8] = 1,
        [OMAP_DMA_DATA_TYPE_S16] = 2,
        [OMAP_DMA_DATA_TYPE_S32] = 4,
};

static inline struct omap_dmadev *to_omap_dma_dev(struct dma_device *d)
{
        return container_of(d, struct omap_dmadev, ddev);
}

static inline struct omap_chan *to_omap_dma_chan(struct dma_chan *c)
{
        return container_of(c, struct omap_chan, vc.chan);
}

static inline struct omap_desc *to_omap_dma_desc(struct dma_async_tx_descriptor *t)
{
        return container_of(t, struct omap_desc, vd.tx);
}

static void omap_dma_desc_free(struct virt_dma_desc *vd)
{
        kfree(container_of(vd, struct omap_desc, vd));
}

static void omap_dma_start_sg(struct omap_chan *c, struct omap_desc *d,
        unsigned idx)
{
        struct omap_sg *sg = d->sg + idx;

        if (d->dir == DMA_DEV_TO_MEM)
                omap_set_dma_dest_params(c->dma_ch, OMAP_DMA_PORT_EMIFF,
                        OMAP_DMA_AMODE_POST_INC, sg->addr, 0, 0);
        else
                omap_set_dma_src_params(c->dma_ch, OMAP_DMA_PORT_EMIFF,
                        OMAP_DMA_AMODE_POST_INC, sg->addr, 0, 0);

        omap_set_dma_transfer_params(c->dma_ch, d->es, sg->en, sg->fn,
                d->sync_mode, c->dma_sig, d->sync_type);

        omap_start_dma(c->dma_ch);
}

static void omap_dma_start_desc(struct omap_chan *c)
{
        struct virt_dma_desc *vd = vchan_next_desc(&c->vc);
        struct omap_desc *d;

        if (!vd) {
                c->desc = NULL;
                return;
        }

        list_del(&vd->node);

        c->desc = d = to_omap_dma_desc(&vd->tx);
        c->sgidx = 0;

        if (d->dir == DMA_DEV_TO_MEM)
                omap_set_dma_src_params(c->dma_ch, d->periph_port,
                        OMAP_DMA_AMODE_CONSTANT, d->dev_addr, 0, d->fi);
        else
                omap_set_dma_dest_params(c->dma_ch, d->periph_port,
                        OMAP_DMA_AMODE_CONSTANT, d->dev_addr, 0, d->fi);

        omap_dma_start_sg(c, d, 0);
}

static void omap_dma_callback(int ch, u16 status, void *data)
{
        struct omap_chan *c = data;
        struct omap_desc *d;
        unsigned long flags;

        spin_lock_irqsave(&c->vc.lock, flags);
        d = c->desc;
        if (d) {
                if (!c->cyclic) {
                        if (++c->sgidx < d->sglen) {
                                omap_dma_start_sg(c, d, c->sgidx);
                        } else {
                                omap_dma_start_desc(c);
                                vchan_cookie_complete(&d->vd);
                        }
                } else {
                        vchan_cyclic_callback(&d->vd);
                }
        }
        spin_unlock_irqrestore(&c->vc.lock, flags);
}

/*
 * This callback schedules all pending channels.  We could be more
 * clever here by postponing allocation of the real DMA channels to
 * this point, and freeing them when our virtual channel becomes idle.
 *
 * We would then need to deal with 'all channels in-use'
 */
static void omap_dma_sched(unsigned long data)
{
        struct omap_dmadev *d = (struct omap_dmadev *)data;
        LIST_HEAD(head);

        spin_lock_irq(&d->lock);
        list_splice_tail_init(&d->pending, &head);
        spin_unlock_irq(&d->lock);

        while (!list_empty(&head)) {
                struct omap_chan *c = list_first_entry(&head,
                        struct omap_chan, node);

                spin_lock_irq(&c->vc.lock);
                list_del_init(&c->node);
                omap_dma_start_desc(c);
                spin_unlock_irq(&c->vc.lock);
        }
}

static int omap_dma_alloc_chan_resources(struct dma_chan *chan)
{
        struct omap_chan *c = to_omap_dma_chan(chan);

        dev_info(c->vc.chan.device->dev, "allocating channel for %u\n", c->dma_sig);

        return omap_request_dma(c->dma_sig, "DMA engine",
                omap_dma_callback, c, &c->dma_ch);
}

static void omap_dma_free_chan_resources(struct dma_chan *chan)
{
        struct omap_chan *c = to_omap_dma_chan(chan);

        vchan_free_chan_resources(&c->vc);
        omap_free_dma(c->dma_ch);

        dev_info(c->vc.chan.device->dev, "freeing channel for %u\n", c->dma_sig);
}

static size_t omap_dma_sg_size(struct omap_sg *sg)
{
        return sg->en * sg->fn;
}

static size_t omap_dma_desc_size(struct omap_desc *d)
{
        unsigned i;
        size_t size;

        for (size = i = 0; i < d->sglen; i++)
                size += omap_dma_sg_size(&d->sg[i]);

        return size * es_bytes[d->es];
}

static size_t omap_dma_desc_size_pos(struct omap_desc *d, dma_addr_t addr)
{
        unsigned i;
        size_t size, es_size = es_bytes[d->es];

        for (size = i = 0; i < d->sglen; i++) {
                size_t this_size = omap_dma_sg_size(&d->sg[i]) * es_size;

                if (size)
                        size += this_size;
                else if (addr >= d->sg[i].addr &&
                         addr < d->sg[i].addr + this_size)
                        size += d->sg[i].addr + this_size - addr;
        }
        return size;
}

static enum dma_status omap_dma_tx_status(struct dma_chan *chan,
        dma_cookie_t cookie, struct dma_tx_state *txstate)
{
        struct omap_chan *c = to_omap_dma_chan(chan);
        struct virt_dma_desc *vd;
        enum dma_status ret;
        unsigned long flags;

        ret = dma_cookie_status(chan, cookie, txstate);
        if (ret == DMA_SUCCESS || !txstate)
                return ret;

        spin_lock_irqsave(&c->vc.lock, flags);
        vd = vchan_find_desc(&c->vc, cookie);
        if (vd) {
                txstate->residue = omap_dma_desc_size(to_omap_dma_desc(&vd->tx));
        } else if (c->desc && c->desc->vd.tx.cookie == cookie) {
                struct omap_desc *d = c->desc;
                dma_addr_t pos;

                if (d->dir == DMA_MEM_TO_DEV)
                        pos = omap_get_dma_src_pos(c->dma_ch);
                else if (d->dir == DMA_DEV_TO_MEM)
                        pos = omap_get_dma_dst_pos(c->dma_ch);
                else
                        pos = 0;

                txstate->residue = omap_dma_desc_size_pos(d, pos);
        } else {
                txstate->residue = 0;
        }
        spin_unlock_irqrestore(&c->vc.lock, flags);

        return ret;
}

static void omap_dma_issue_pending(struct dma_chan *chan)
{
        struct omap_chan *c = to_omap_dma_chan(chan);
        unsigned long flags;

        spin_lock_irqsave(&c->vc.lock, flags);
        if (vchan_issue_pending(&c->vc) && !c->desc) {
                struct omap_dmadev *d = to_omap_dma_dev(chan->device);
                spin_lock(&d->lock);
                if (list_empty(&c->node))
                        list_add_tail(&c->node, &d->pending);
                spin_unlock(&d->lock);
                tasklet_schedule(&d->task);
        }
        spin_unlock_irqrestore(&c->vc.lock, flags);
}

static struct dma_async_tx_descriptor *omap_dma_prep_slave_sg(
        struct dma_chan *chan, struct scatterlist *sgl, unsigned sglen,
        enum dma_transfer_direction dir, unsigned long tx_flags, void *context)
{
        struct omap_chan *c = to_omap_dma_chan(chan);
        enum dma_slave_buswidth dev_width;
        struct scatterlist *sgent;
        struct omap_desc *d;
        dma_addr_t dev_addr;
        unsigned i, j = 0, es, en, frame_bytes, sync_type;
        u32 burst;

        if (dir == DMA_DEV_TO_MEM) {
                dev_addr = c->cfg.src_addr;
                dev_width = c->cfg.src_addr_width;
                burst = c->cfg.src_maxburst;
                sync_type = OMAP_DMA_SRC_SYNC;
        } else if (dir == DMA_MEM_TO_DEV) {
                dev_addr = c->cfg.dst_addr;
                dev_width = c->cfg.dst_addr_width;
                burst = c->cfg.dst_maxburst;
                sync_type = OMAP_DMA_DST_SYNC;
        } else {
                dev_err(chan->device->dev, "%s: bad direction?\n", __func__);
                return NULL;
        }

        /* Bus width translates to the element size (ES) */
        switch (dev_width) {
        case DMA_SLAVE_BUSWIDTH_1_BYTE:
                es = OMAP_DMA_DATA_TYPE_S8;
                break;
        case DMA_SLAVE_BUSWIDTH_2_BYTES:
                es = OMAP_DMA_DATA_TYPE_S16;
                break;
        case DMA_SLAVE_BUSWIDTH_4_BYTES:
                es = OMAP_DMA_DATA_TYPE_S32;
                break;
        default: /* not reached */
                return NULL;
        }

        /* Now allocate and setup the descriptor. */
        d = kzalloc(sizeof(*d) + sglen * sizeof(d->sg[0]), GFP_ATOMIC);
        if (!d)
                return NULL;

        d->dir = dir;
        d->dev_addr = dev_addr;
        d->es = es;
        d->sync_mode = OMAP_DMA_SYNC_FRAME;
        d->sync_type = sync_type;
        d->periph_port = OMAP_DMA_PORT_TIPB;

        /*
         * Build our scatterlist entries: each contains the address,
         * the number of elements (EN) in each frame, and the number of
         * frames (FN).  Number of bytes for this entry = ES * EN * FN.
         *
         * Burst size translates to number of elements with frame sync.
         * Note: DMA engine defines burst to be the number of dev-width
         * transfers.
         */
        en = burst;
        frame_bytes = es_bytes[es] * en;
        for_each_sg(sgl, sgent, sglen, i) {
                d->sg[j].addr = sg_dma_address(sgent);
                d->sg[j].en = en;
                d->sg[j].fn = sg_dma_len(sgent) / frame_bytes;
                j++;
        }

        d->sglen = j;

        return vchan_tx_prep(&c->vc, &d->vd, tx_flags);
}

static struct dma_async_tx_descriptor *omap_dma_prep_dma_cyclic(
        struct dma_chan *chan, dma_addr_t buf_addr, size_t buf_len,
        size_t period_len, enum dma_transfer_direction dir, unsigned long flags,
        void *context)
{
        struct omap_chan *c = to_omap_dma_chan(chan);
        enum dma_slave_buswidth dev_width;
        struct omap_desc *d;
        dma_addr_t dev_addr;
        unsigned es, sync_type;
        u32 burst;

        if (dir == DMA_DEV_TO_MEM) {
                dev_addr = c->cfg.src_addr;
                dev_width = c->cfg.src_addr_width;
                burst = c->cfg.src_maxburst;
                sync_type = OMAP_DMA_SRC_SYNC;
        } else if (dir == DMA_MEM_TO_DEV) {
                dev_addr = c->cfg.dst_addr;
                dev_width = c->cfg.dst_addr_width;
                burst = c->cfg.dst_maxburst;
                sync_type = OMAP_DMA_DST_SYNC;
        } else {
                dev_err(chan->device->dev, "%s: bad direction?\n", __func__);
                return NULL;
        }

        /* Bus width translates to the element size (ES) */
        switch (dev_width) {
        case DMA_SLAVE_BUSWIDTH_1_BYTE:
                es = OMAP_DMA_DATA_TYPE_S8;
                break;
        case DMA_SLAVE_BUSWIDTH_2_BYTES:
                es = OMAP_DMA_DATA_TYPE_S16;
                break;
        case DMA_SLAVE_BUSWIDTH_4_BYTES:
                es = OMAP_DMA_DATA_TYPE_S32;
                break;
        default: /* not reached */
                return NULL;
        }

        /* Now allocate and setup the descriptor. */
        d = kzalloc(sizeof(*d) + sizeof(d->sg[0]), GFP_ATOMIC);
        if (!d)
                return NULL;

        d->dir = dir;
        d->dev_addr = dev_addr;
        d->fi = burst;
        d->es = es;
        if (burst)
                d->sync_mode = OMAP_DMA_SYNC_PACKET;
        else
                d->sync_mode = OMAP_DMA_SYNC_ELEMENT;
        d->sync_type = sync_type;
        d->periph_port = OMAP_DMA_PORT_MPUI;
        d->sg[0].addr = buf_addr;
        d->sg[0].en = period_len / es_bytes[es];
        d->sg[0].fn = buf_len / period_len;
        d->sglen = 1;

        if (!c->cyclic) {
                c->cyclic = true;
                omap_dma_link_lch(c->dma_ch, c->dma_ch);

                if (flags & DMA_PREP_INTERRUPT)
                        omap_enable_dma_irq(c->dma_ch, OMAP_DMA_FRAME_IRQ);

                omap_disable_dma_irq(c->dma_ch, OMAP_DMA_BLOCK_IRQ);
        }

        if (!cpu_class_is_omap1()) {
                omap_set_dma_src_burst_mode(c->dma_ch, OMAP_DMA_DATA_BURST_16);
                omap_set_dma_dest_burst_mode(c->dma_ch, OMAP_DMA_DATA_BURST_16);
        }

        return vchan_tx_prep(&c->vc, &d->vd, flags);
}

static int omap_dma_slave_config(struct omap_chan *c, struct dma_slave_config *cfg)
{
        if (cfg->src_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES ||
            cfg->dst_addr_width == DMA_SLAVE_BUSWIDTH_8_BYTES)
                return -EINVAL;

        memcpy(&c->cfg, cfg, sizeof(c->cfg));

        return 0;
}

static int omap_dma_terminate_all(struct omap_chan *c)
{
        struct omap_dmadev *d = to_omap_dma_dev(c->vc.chan.device);
        unsigned long flags;
        LIST_HEAD(head);

        spin_lock_irqsave(&c->vc.lock, flags);

        /* Prevent this channel being scheduled */
        spin_lock(&d->lock);
        list_del_init(&c->node);
        spin_unlock(&d->lock);

        /*
         * Stop DMA activity: we assume the callback will not be called
         * after omap_stop_dma() returns (even if it does, it will see
         * c->desc is NULL and exit.)
         */
        if (c->desc) {
                c->desc = NULL;
                /* Avoid stopping the dma twice */
                if (!c->paused)
                        omap_stop_dma(c->dma_ch);
        }

        if (c->cyclic) {
                c->cyclic = false;
                c->paused = false;
                omap_dma_unlink_lch(c->dma_ch, c->dma_ch);
        }

        vchan_get_all_descriptors(&c->vc, &head);
        spin_unlock_irqrestore(&c->vc.lock, flags);
        vchan_dma_desc_free_list(&c->vc, &head);

        return 0;
}

static int omap_dma_pause(struct omap_chan *c)
{
        /* Pause/Resume only allowed with cyclic mode */
        if (!c->cyclic)
                return -EINVAL;

        if (!c->paused) {
                omap_stop_dma(c->dma_ch);
                c->paused = true;
        }

        return 0;
}

static int omap_dma_resume(struct omap_chan *c)
{
        /* Pause/Resume only allowed with cyclic mode */
        if (!c->cyclic)
                return -EINVAL;

        if (c->paused) {
                omap_start_dma(c->dma_ch);
                c->paused = false;
        }

        return 0;
}

static int omap_dma_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
        unsigned long arg)
{
        struct omap_chan *c = to_omap_dma_chan(chan);
        int ret;

        switch (cmd) {
        case DMA_SLAVE_CONFIG:
                ret = omap_dma_slave_config(c, (struct dma_slave_config *)arg);
                break;

        case DMA_TERMINATE_ALL:
                ret = omap_dma_terminate_all(c);
                break;

        case DMA_PAUSE:
                ret = omap_dma_pause(c);
                break;

        case DMA_RESUME:
                ret = omap_dma_resume(c);
                break;

        default:
                ret = -ENXIO;
                break;
        }

        return ret;
}

static int omap_dma_chan_init(struct omap_dmadev *od, int dma_sig)
{
        struct omap_chan *c;

        c = kzalloc(sizeof(*c), GFP_KERNEL);
        if (!c)
                return -ENOMEM;

        c->dma_sig = dma_sig;
        c->vc.desc_free = omap_dma_desc_free;
        vchan_init(&c->vc, &od->ddev);
        INIT_LIST_HEAD(&c->node);

        od->ddev.chancnt++;

        return 0;
}

static void omap_dma_free(struct omap_dmadev *od)
{
        tasklet_kill(&od->task);
        while (!list_empty(&od->ddev.channels)) {
                struct omap_chan *c = list_first_entry(&od->ddev.channels,
                        struct omap_chan, vc.chan.device_node);

                list_del(&c->vc.chan.device_node);
                tasklet_kill(&c->vc.task);
                kfree(c);
        }
        kfree(od);
}

static int omap_dma_probe(struct platform_device *pdev)
{
        struct omap_dmadev *od;
        int rc, i;

        od = kzalloc(sizeof(*od), GFP_KERNEL);
        if (!od)
                return -ENOMEM;

        dma_cap_set(DMA_SLAVE, od->ddev.cap_mask);
        dma_cap_set(DMA_CYCLIC, od->ddev.cap_mask);
        od->ddev.device_alloc_chan_resources = omap_dma_alloc_chan_resources;
        od->ddev.device_free_chan_resources = omap_dma_free_chan_resources;
        od->ddev.device_tx_status = omap_dma_tx_status;
        od->ddev.device_issue_pending = omap_dma_issue_pending;
        od->ddev.device_prep_slave_sg = omap_dma_prep_slave_sg;
        od->ddev.device_prep_dma_cyclic = omap_dma_prep_dma_cyclic;
        od->ddev.device_control = omap_dma_control;
        od->ddev.dev = &pdev->dev;
        INIT_LIST_HEAD(&od->ddev.channels);
        INIT_LIST_HEAD(&od->pending);
        spin_lock_init(&od->lock);

        tasklet_init(&od->task, omap_dma_sched, (unsigned long)od);

        for (i = 0; i < 127; i++) {
                rc = omap_dma_chan_init(od, i);
                if (rc) {
                        omap_dma_free(od);
                        return rc;
                }
        }

        rc = dma_async_device_register(&od->ddev);
        if (rc) {
                pr_warn("OMAP-DMA: failed to register slave DMA engine device: %d\n",
                        rc);
                omap_dma_free(od);
        } else {
                platform_set_drvdata(pdev, od);
        }

        dev_info(&pdev->dev, "OMAP DMA engine driver\n");

        return rc;
}

static int omap_dma_remove(struct platform_device *pdev)
{
        struct omap_dmadev *od = platform_get_drvdata(pdev);

        dma_async_device_unregister(&od->ddev);
        omap_dma_free(od);

        return 0;
}

static struct platform_driver omap_dma_driver = {
        .probe  = omap_dma_probe,
        .remove = omap_dma_remove,
        .driver = {
                .name = "omap-dma-engine",
                .owner = THIS_MODULE,
        },
};

bool omap_dma_filter_fn(struct dma_chan *chan, void *param)
{
        if (chan->device->dev->driver == &omap_dma_driver.driver) {
                struct omap_chan *c = to_omap_dma_chan(chan);
                unsigned req = *(unsigned *)param;

                return req == c->dma_sig;
        }
        return false;
}
EXPORT_SYMBOL_GPL(omap_dma_filter_fn);

static struct platform_device *pdev;

static const struct platform_device_info omap_dma_dev_info = {
        .name = "omap-dma-engine",
        .id = -1,
        .dma_mask = DMA_BIT_MASK(32),
};

static int omap_dma_init(void)
{
        int rc = platform_driver_register(&omap_dma_driver);

        if (rc == 0) {
                pdev = platform_device_register_full(&omap_dma_dev_info);
                if (IS_ERR(pdev)) {
                        platform_driver_unregister(&omap_dma_driver);
                        rc = PTR_ERR(pdev);
                }
        }
        return rc;
}
subsys_initcall(omap_dma_init);

static void __exit omap_dma_exit(void)
{
        platform_device_unregister(pdev);
        platform_driver_unregister(&omap_dma_driver);
}
module_exit(omap_dma_exit);

MODULE_AUTHOR("Russell King");
MODULE_LICENSE("GPL");