/*
 * drivers/media/video/omap24xxcam-dma.c
 *
 * Copyright (C) 2004 MontaVista Software, Inc.
 * Copyright (C) 2004 Texas Instruments.
 * Copyright (C) 2007 Nokia Corporation.
 *
 * Contact: Sakari Ailus <sakari.ailus@nokia.com>
 *
 * Based on code from Andy Lowe <source@mvista.com> and
 *                    David Cohen <david.cohen@indt.org.br>.
 *
 * 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.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA
 */

#include <linux/kernel.h>
#include <linux/io.h>
#include <linux/scatterlist.h>

#include "omap24xxcam.h"

/*
 *
 * DMA hardware.
 *
 */

/* Ack all interrupt on CSR and IRQSTATUS_L0 */
static void omap24xxcam_dmahw_ack_all(unsigned long base)
{
        u32 csr;
        int i;

        for (i = 0; i < NUM_CAMDMA_CHANNELS; ++i) {
                csr = omap24xxcam_reg_in(base, CAMDMA_CSR(i));
                /* ack interrupt in CSR */
                omap24xxcam_reg_out(base, CAMDMA_CSR(i), csr);
        }
        omap24xxcam_reg_out(base, CAMDMA_IRQSTATUS_L0, 0xf);
}

/* Ack dmach on CSR and IRQSTATUS_L0 */
static u32 omap24xxcam_dmahw_ack_ch(unsigned long base, int dmach)
{
        u32 csr;

        csr = omap24xxcam_reg_in(base, CAMDMA_CSR(dmach));
        /* ack interrupt in CSR */
        omap24xxcam_reg_out(base, CAMDMA_CSR(dmach), csr);
        /* ack interrupt in IRQSTATUS */
        omap24xxcam_reg_out(base, CAMDMA_IRQSTATUS_L0, (1 << dmach));

        return csr;
}

static int omap24xxcam_dmahw_running(unsigned long base, int dmach)
{
        return omap24xxcam_reg_in(base, CAMDMA_CCR(dmach)) & CAMDMA_CCR_ENABLE;
}

static void omap24xxcam_dmahw_transfer_setup(unsigned long base, int dmach,
                                             dma_addr_t start, u32 len)
{
        omap24xxcam_reg_out(base, CAMDMA_CCR(dmach),
                            CAMDMA_CCR_SEL_SRC_DST_SYNC
                            | CAMDMA_CCR_BS
                            | CAMDMA_CCR_DST_AMODE_POST_INC
                            | CAMDMA_CCR_SRC_AMODE_POST_INC
                            | CAMDMA_CCR_FS
                            | CAMDMA_CCR_WR_ACTIVE
                            | CAMDMA_CCR_RD_ACTIVE
                            | CAMDMA_CCR_SYNCHRO_CAMERA);
        omap24xxcam_reg_out(base, CAMDMA_CLNK_CTRL(dmach), 0);
        omap24xxcam_reg_out(base, CAMDMA_CEN(dmach), len);
        omap24xxcam_reg_out(base, CAMDMA_CFN(dmach), 1);
        omap24xxcam_reg_out(base, CAMDMA_CSDP(dmach),
                            CAMDMA_CSDP_WRITE_MODE_POSTED
                            | CAMDMA_CSDP_DST_BURST_EN_32
                            | CAMDMA_CSDP_DST_PACKED
                            | CAMDMA_CSDP_SRC_BURST_EN_32
                            | CAMDMA_CSDP_SRC_PACKED
                            | CAMDMA_CSDP_DATA_TYPE_8BITS);
        omap24xxcam_reg_out(base, CAMDMA_CSSA(dmach), 0);
        omap24xxcam_reg_out(base, CAMDMA_CDSA(dmach), start);
        omap24xxcam_reg_out(base, CAMDMA_CSEI(dmach), 0);
        omap24xxcam_reg_out(base, CAMDMA_CSFI(dmach), DMA_THRESHOLD);
        omap24xxcam_reg_out(base, CAMDMA_CDEI(dmach), 0);
        omap24xxcam_reg_out(base, CAMDMA_CDFI(dmach), 0);
        omap24xxcam_reg_out(base, CAMDMA_CSR(dmach),
                            CAMDMA_CSR_MISALIGNED_ERR
                            | CAMDMA_CSR_SECURE_ERR
                            | CAMDMA_CSR_TRANS_ERR
                            | CAMDMA_CSR_BLOCK
                            | CAMDMA_CSR_DROP);
        omap24xxcam_reg_out(base, CAMDMA_CICR(dmach),
                            CAMDMA_CICR_MISALIGNED_ERR_IE
                            | CAMDMA_CICR_SECURE_ERR_IE
                            | CAMDMA_CICR_TRANS_ERR_IE
                            | CAMDMA_CICR_BLOCK_IE
                            | CAMDMA_CICR_DROP_IE);
}

static void omap24xxcam_dmahw_transfer_start(unsigned long base, int dmach)
{
        omap24xxcam_reg_out(base, CAMDMA_CCR(dmach),
                            CAMDMA_CCR_SEL_SRC_DST_SYNC
                            | CAMDMA_CCR_BS
                            | CAMDMA_CCR_DST_AMODE_POST_INC
                            | CAMDMA_CCR_SRC_AMODE_POST_INC
                            | CAMDMA_CCR_ENABLE
                            | CAMDMA_CCR_FS
                            | CAMDMA_CCR_SYNCHRO_CAMERA);
}

static void omap24xxcam_dmahw_transfer_chain(unsigned long base, int dmach,
                                             int free_dmach)
{
        int prev_dmach, ch;

        if (dmach == 0)
                prev_dmach = NUM_CAMDMA_CHANNELS - 1;
        else
                prev_dmach = dmach - 1;
        omap24xxcam_reg_out(base, CAMDMA_CLNK_CTRL(prev_dmach),
                            CAMDMA_CLNK_CTRL_ENABLE_LNK | dmach);
        /* Did we chain the DMA transfer before the previous one
         * finished?
         */
        ch = (dmach + free_dmach) % NUM_CAMDMA_CHANNELS;
        while (!(omap24xxcam_reg_in(base, CAMDMA_CCR(ch))
                 & CAMDMA_CCR_ENABLE)) {
                if (ch == dmach) {
                        /* The previous transfer has ended and this one
                         * hasn't started, so we must not have chained
                         * to the previous one in time.  We'll have to
                         * start it now.
                         */
                        omap24xxcam_dmahw_transfer_start(base, dmach);
                        break;
                } else
                        ch = (ch + 1) % NUM_CAMDMA_CHANNELS;
        }
}

/* Abort all chained DMA transfers. After all transfers have been
 * aborted and the DMA controller is idle, the completion routines for
 * any aborted transfers will be called in sequence. The DMA
 * controller may not be idle after this routine completes, because
 * the completion routines might start new transfers.
 */
static void omap24xxcam_dmahw_abort_ch(unsigned long base, int dmach)
{
        /* mask all interrupts from this channel */
        omap24xxcam_reg_out(base, CAMDMA_CICR(dmach), 0);
        /* unlink this channel */
        omap24xxcam_reg_merge(base, CAMDMA_CLNK_CTRL(dmach), 0,
                              CAMDMA_CLNK_CTRL_ENABLE_LNK);
        /* disable this channel */
        omap24xxcam_reg_merge(base, CAMDMA_CCR(dmach), 0, CAMDMA_CCR_ENABLE);
}

static void omap24xxcam_dmahw_init(unsigned long base)
{
        omap24xxcam_reg_out(base, CAMDMA_OCP_SYSCONFIG,
                            CAMDMA_OCP_SYSCONFIG_MIDLEMODE_FSTANDBY
                            | CAMDMA_OCP_SYSCONFIG_SIDLEMODE_FIDLE
                            | CAMDMA_OCP_SYSCONFIG_AUTOIDLE);

        omap24xxcam_reg_merge(base, CAMDMA_GCR, 0x10,
                              CAMDMA_GCR_MAX_CHANNEL_FIFO_DEPTH);

        omap24xxcam_reg_out(base, CAMDMA_IRQENABLE_L0, 0xf);
}

/*
 *
 * Individual DMA channel handling.
 *
 */

/* Start a DMA transfer from the camera to memory.
 * Returns zero if the transfer was successfully started, or non-zero if all
 * DMA channels are already in use or starting is currently inhibited.
 */
static int omap24xxcam_dma_start(struct omap24xxcam_dma *dma, dma_addr_t start,
                                 u32 len, dma_callback_t callback, void *arg)
{
        unsigned long flags;
        int dmach;

        spin_lock_irqsave(&dma->lock, flags);

        if (!dma->free_dmach || atomic_read(&dma->dma_stop)) {
                spin_unlock_irqrestore(&dma->lock, flags);
                return -EBUSY;
        }

        dmach = dma->next_dmach;

        dma->ch_state[dmach].callback = callback;
        dma->ch_state[dmach].arg = arg;

        omap24xxcam_dmahw_transfer_setup(dma->base, dmach, start, len);

        /* We're ready to start the DMA transfer. */

        if (dma->free_dmach < NUM_CAMDMA_CHANNELS) {
                /* A transfer is already in progress, so try to chain to it. */
                omap24xxcam_dmahw_transfer_chain(dma->base, dmach,
                                                 dma->free_dmach);
        } else {
                /* No transfer is in progress, so we'll just start this one
                 * now.
                 */
                omap24xxcam_dmahw_transfer_start(dma->base, dmach);
        }

        dma->next_dmach = (dma->next_dmach + 1) % NUM_CAMDMA_CHANNELS;
        dma->free_dmach--;

        spin_unlock_irqrestore(&dma->lock, flags);

        return 0;
}

/* Abort all chained DMA transfers. After all transfers have been
 * aborted and the DMA controller is idle, the completion routines for
 * any aborted transfers will be called in sequence. The DMA
 * controller may not be idle after this routine completes, because
 * the completion routines might start new transfers.
 */
static void omap24xxcam_dma_abort(struct omap24xxcam_dma *dma, u32 csr)
{
        unsigned long flags;
        int dmach, i, free_dmach;
        dma_callback_t callback;
        void *arg;

        spin_lock_irqsave(&dma->lock, flags);

        /* stop any DMA transfers in progress */
        dmach = (dma->next_dmach + dma->free_dmach) % NUM_CAMDMA_CHANNELS;
        for (i = 0; i < NUM_CAMDMA_CHANNELS; i++) {
                omap24xxcam_dmahw_abort_ch(dma->base, dmach);
                dmach = (dmach + 1) % NUM_CAMDMA_CHANNELS;
        }

        /* We have to be careful here because the callback routine
         * might start a new DMA transfer, and we only want to abort
         * transfers that were started before this routine was called.
         */
        free_dmach = dma->free_dmach;
        while ((dma->free_dmach < NUM_CAMDMA_CHANNELS) &&
               (free_dmach < NUM_CAMDMA_CHANNELS)) {
                dmach = (dma->next_dmach + dma->free_dmach)
                        % NUM_CAMDMA_CHANNELS;
                callback = dma->ch_state[dmach].callback;
                arg = dma->ch_state[dmach].arg;
                dma->free_dmach++;
                free_dmach++;
                if (callback) {
                        /* leave interrupts disabled during callback */
                        spin_unlock(&dma->lock);
                        (*callback) (dma, csr, arg);
                        spin_lock(&dma->lock);
                }
        }

        spin_unlock_irqrestore(&dma->lock, flags);
}

/* Abort all chained DMA transfers. After all transfers have been
 * aborted and the DMA controller is idle, the completion routines for
 * any aborted transfers will be called in sequence. If the completion
 * routines attempt to start a new DMA transfer it will fail, so the
 * DMA controller will be idle after this routine completes.
 */
static void omap24xxcam_dma_stop(struct omap24xxcam_dma *dma, u32 csr)
{
        atomic_inc(&dma->dma_stop);
        omap24xxcam_dma_abort(dma, csr);
        atomic_dec(&dma->dma_stop);
}

/* Camera DMA interrupt service routine. */
void omap24xxcam_dma_isr(struct omap24xxcam_dma *dma)
{
        int dmach;
        dma_callback_t callback;
        void *arg;
        u32 csr;
        const u32 csr_error = CAMDMA_CSR_MISALIGNED_ERR
                | CAMDMA_CSR_SUPERVISOR_ERR | CAMDMA_CSR_SECURE_ERR
                | CAMDMA_CSR_TRANS_ERR | CAMDMA_CSR_DROP;

        spin_lock(&dma->lock);

        if (dma->free_dmach == NUM_CAMDMA_CHANNELS) {
                /* A camera DMA interrupt occurred while all channels
                 * are idle, so we'll acknowledge the interrupt in the
                 * IRQSTATUS register and exit.
                 */
                omap24xxcam_dmahw_ack_all(dma->base);
                spin_unlock(&dma->lock);
                return;
        }

        while (dma->free_dmach < NUM_CAMDMA_CHANNELS) {
                dmach = (dma->next_dmach + dma->free_dmach)
                        % NUM_CAMDMA_CHANNELS;
                if (omap24xxcam_dmahw_running(dma->base, dmach)) {
                        /* This buffer hasn't finished yet, so we're done. */
                        break;
                }
                csr = omap24xxcam_dmahw_ack_ch(dma->base, dmach);
                if (csr & csr_error) {
                        /* A DMA error occurred, so stop all DMA
                         * transfers in progress.
                         */
                        spin_unlock(&dma->lock);
                        omap24xxcam_dma_stop(dma, csr);
                        return;
                } else {
                        callback = dma->ch_state[dmach].callback;
                        arg = dma->ch_state[dmach].arg;
                        dma->free_dmach++;
                        if (callback) {
                                spin_unlock(&dma->lock);
                                (*callback) (dma, csr, arg);
                                spin_lock(&dma->lock);
                        }
                }
        }

        spin_unlock(&dma->lock);

        omap24xxcam_sgdma_process(
                container_of(dma, struct omap24xxcam_sgdma, dma));
}

void omap24xxcam_dma_hwinit(struct omap24xxcam_dma *dma)
{
        unsigned long flags;

        spin_lock_irqsave(&dma->lock, flags);

        omap24xxcam_dmahw_init(dma->base);

        spin_unlock_irqrestore(&dma->lock, flags);
}

static void omap24xxcam_dma_init(struct omap24xxcam_dma *dma,
                                 unsigned long base)
{
        int ch;

        /* group all channels on DMA IRQ0 and unmask irq */
        spin_lock_init(&dma->lock);
        dma->base = base;
        dma->free_dmach = NUM_CAMDMA_CHANNELS;
        dma->next_dmach = 0;
        for (ch = 0; ch < NUM_CAMDMA_CHANNELS; ch++) {
                dma->ch_state[ch].callback = NULL;
                dma->ch_state[ch].arg = NULL;
        }
}

/*
 *
 * Scatter-gather DMA.
 *
 * High-level DMA construct for transferring whole picture frames to
 * memory that is discontinuous.
 *
 */

/* DMA completion routine for the scatter-gather DMA fragments. */
static void omap24xxcam_sgdma_callback(struct omap24xxcam_dma *dma, u32 csr,
                                       void *arg)
{
        struct omap24xxcam_sgdma *sgdma =
                container_of(dma, struct omap24xxcam_sgdma, dma);
        int sgslot = (int)arg;
        struct sgdma_state *sg_state;
        const u32 csr_error = CAMDMA_CSR_MISALIGNED_ERR
                | CAMDMA_CSR_SUPERVISOR_ERR | CAMDMA_CSR_SECURE_ERR
                | CAMDMA_CSR_TRANS_ERR | CAMDMA_CSR_DROP;

        spin_lock(&sgdma->lock);

        /* We got an interrupt, we can remove the timer */
        del_timer(&sgdma->reset_timer);

        sg_state = sgdma->sg_state + sgslot;
        if (!sg_state->queued_sglist) {
                spin_unlock(&sgdma->lock);
                printk(KERN_ERR "%s: sgdma completed when none queued!\n",
                       __func__);
                return;
        }

        sg_state->csr |= csr;
        if (!--sg_state->queued_sglist) {
                /* Queue for this sglist is empty, so check to see if we're
                 * done.
                 */
                if ((sg_state->next_sglist == sg_state->sglen)
                    || (sg_state->csr & csr_error)) {
                        sgdma_callback_t callback = sg_state->callback;
                        void *arg = sg_state->arg;
                        u32 sg_csr = sg_state->csr;
                        /* All done with this sglist */
                        sgdma->free_sgdma++;
                        if (callback) {
                                spin_unlock(&sgdma->lock);
                                (*callback) (sgdma, sg_csr, arg);
                                return;
                        }
                }
        }

        spin_unlock(&sgdma->lock);
}

/* Start queued scatter-gather DMA transfers. */
void omap24xxcam_sgdma_process(struct omap24xxcam_sgdma *sgdma)
{
        unsigned long flags;
        int queued_sgdma, sgslot;
        struct sgdma_state *sg_state;
        const u32 csr_error = CAMDMA_CSR_MISALIGNED_ERR
                | CAMDMA_CSR_SUPERVISOR_ERR | CAMDMA_CSR_SECURE_ERR
                | CAMDMA_CSR_TRANS_ERR | CAMDMA_CSR_DROP;

        spin_lock_irqsave(&sgdma->lock, flags);

        queued_sgdma = NUM_SG_DMA - sgdma->free_sgdma;
        sgslot = (sgdma->next_sgdma + sgdma->free_sgdma) % NUM_SG_DMA;
        while (queued_sgdma > 0) {
                sg_state = sgdma->sg_state + sgslot;
                while ((sg_state->next_sglist < sg_state->sglen) &&
                       !(sg_state->csr & csr_error)) {
                        const struct scatterlist *sglist;
                        unsigned int len;

                        sglist = sg_state->sglist + sg_state->next_sglist;
                        /* try to start the next DMA transfer */
                        if (sg_state->next_sglist + 1 == sg_state->sglen) {
                                /*
                                 *  On the last sg, we handle the case where
                                 *  cam->img.pix.sizeimage % PAGE_ALIGN != 0
                                 */
                                len = sg_state->len - sg_state->bytes_read;
                        } else {
                                len = sg_dma_len(sglist);
                        }

                        if (omap24xxcam_dma_start(&sgdma->dma,
                                                  sg_dma_address(sglist),
                                                  len,
                                                  omap24xxcam_sgdma_callback,
                                                  (void *)sgslot)) {
                                /* DMA start failed */
                                spin_unlock_irqrestore(&sgdma->lock, flags);
                                return;
                        } else {
                                unsigned long expires;
                                /* DMA start was successful */
                                sg_state->next_sglist++;
                                sg_state->bytes_read += len;
                                sg_state->queued_sglist++;

                                /* We start the reset timer */
                                expires = jiffies + HZ;
                                mod_timer(&sgdma->reset_timer, expires);
                        }
                }
                queued_sgdma--;
                sgslot = (sgslot + 1) % NUM_SG_DMA;
        }

        spin_unlock_irqrestore(&sgdma->lock, flags);
}

/*
 * Queue a scatter-gather DMA transfer from the camera to memory.
 * Returns zero if the transfer was successfully queued, or non-zero
 * if all of the scatter-gather slots are already in use.
 */
int omap24xxcam_sgdma_queue(struct omap24xxcam_sgdma *sgdma,
                            const struct scatterlist *sglist, int sglen,
                            int len, sgdma_callback_t callback, void *arg)
{
        unsigned long flags;
        struct sgdma_state *sg_state;

        if ((sglen < 0) || ((sglen > 0) & !sglist))
                return -EINVAL;

        spin_lock_irqsave(&sgdma->lock, flags);

        if (!sgdma->free_sgdma) {
                spin_unlock_irqrestore(&sgdma->lock, flags);
                return -EBUSY;
        }

        sg_state = sgdma->sg_state + sgdma->next_sgdma;

        sg_state->sglist = sglist;
        sg_state->sglen = sglen;
        sg_state->next_sglist = 0;
        sg_state->bytes_read = 0;
        sg_state->len = len;
        sg_state->queued_sglist = 0;
        sg_state->csr = 0;
        sg_state->callback = callback;
        sg_state->arg = arg;

        sgdma->next_sgdma = (sgdma->next_sgdma + 1) % NUM_SG_DMA;
        sgdma->free_sgdma--;

        spin_unlock_irqrestore(&sgdma->lock, flags);

        omap24xxcam_sgdma_process(sgdma);

        return 0;
}

/* Sync scatter-gather DMA by aborting any DMA transfers currently in progress.
 * Any queued scatter-gather DMA transactions that have not yet been started
 * will remain queued.  The DMA controller will be idle after this routine
 * completes.  When the scatter-gather queue is restarted, the next
 * scatter-gather DMA transfer will begin at the start of a new transaction.
 */
void omap24xxcam_sgdma_sync(struct omap24xxcam_sgdma *sgdma)
{
        unsigned long flags;
        int sgslot;
        struct sgdma_state *sg_state;
        u32 csr = CAMDMA_CSR_TRANS_ERR;

        /* stop any DMA transfers in progress */
        omap24xxcam_dma_stop(&sgdma->dma, csr);

        spin_lock_irqsave(&sgdma->lock, flags);

        if (sgdma->free_sgdma < NUM_SG_DMA) {
                sgslot = (sgdma->next_sgdma + sgdma->free_sgdma) % NUM_SG_DMA;
                sg_state = sgdma->sg_state + sgslot;
                if (sg_state->next_sglist != 0) {
                        /* This DMA transfer was in progress, so abort it. */
                        sgdma_callback_t callback = sg_state->callback;
                        void *arg = sg_state->arg;
                        sgdma->free_sgdma++;
                        if (callback) {
                                /* leave interrupts masked */
                                spin_unlock(&sgdma->lock);
                                (*callback) (sgdma, csr, arg);
                                spin_lock(&sgdma->lock);
                        }
                }
        }

        spin_unlock_irqrestore(&sgdma->lock, flags);
}

void omap24xxcam_sgdma_init(struct omap24xxcam_sgdma *sgdma,
                            unsigned long base,
                            void (*reset_callback)(unsigned long data),
                            unsigned long reset_callback_data)
{
        int sg;

        spin_lock_init(&sgdma->lock);
        sgdma->free_sgdma = NUM_SG_DMA;
        sgdma->next_sgdma = 0;
        for (sg = 0; sg < NUM_SG_DMA; sg++) {
                sgdma->sg_state[sg].sglen = 0;
                sgdma->sg_state[sg].next_sglist = 0;
                sgdma->sg_state[sg].bytes_read = 0;
                sgdma->sg_state[sg].queued_sglist = 0;
                sgdma->sg_state[sg].csr = 0;
                sgdma->sg_state[sg].callback = NULL;
                sgdma->sg_state[sg].arg = NULL;
        }

        omap24xxcam_dma_init(&sgdma->dma, base);
        setup_timer(&sgdma->reset_timer, reset_callback, reset_callback_data);
}