/*
 * Copyright (C) 2008
 * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
 *
 * Copyright (C) 2005-2007 Freescale Semiconductor, Inc. All Rights Reserved.
 *
 * 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/dma-mapping.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/err.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/list.h>
#include <linux/clk.h>
#include <linux/vmalloc.h>
#include <linux/string.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/module.h>

#include <mach/ipu.h>

#include "../dmaengine.h"
#include "ipu_intern.h"

#define FS_VF_IN_VALID  0x00000002
#define FS_ENC_IN_VALID 0x00000001

static int ipu_disable_channel(struct idmac *idmac, struct idmac_channel *ichan,
                               bool wait_for_stop);

/*
 * There can be only one, we could allocate it dynamically, but then we'd have
 * to add an extra parameter to some functions, and use something as ugly as
 *      struct ipu *ipu = to_ipu(to_idmac(ichan->dma_chan.device));
 * in the ISR
 */
static struct ipu ipu_data;

#define to_ipu(id) container_of(id, struct ipu, idmac)

static u32 __idmac_read_icreg(struct ipu *ipu, unsigned long reg)
{
        return __raw_readl(ipu->reg_ic + reg);
}

#define idmac_read_icreg(ipu, reg) __idmac_read_icreg(ipu, reg - IC_CONF)

static void __idmac_write_icreg(struct ipu *ipu, u32 value, unsigned long reg)
{
        __raw_writel(value, ipu->reg_ic + reg);
}

#define idmac_write_icreg(ipu, v, reg) __idmac_write_icreg(ipu, v, reg - IC_CONF)

static u32 idmac_read_ipureg(struct ipu *ipu, unsigned long reg)
{
        return __raw_readl(ipu->reg_ipu + reg);
}

static void idmac_write_ipureg(struct ipu *ipu, u32 value, unsigned long reg)
{
        __raw_writel(value, ipu->reg_ipu + reg);
}

/*****************************************************************************
 * IPU / IC common functions
 */
static void dump_idmac_reg(struct ipu *ipu)
{
        dev_dbg(ipu->dev, "IDMAC_CONF 0x%x, IC_CONF 0x%x, IDMAC_CHA_EN 0x%x, "
                "IDMAC_CHA_PRI 0x%x, IDMAC_CHA_BUSY 0x%x\n",
                idmac_read_icreg(ipu, IDMAC_CONF),
                idmac_read_icreg(ipu, IC_CONF),
                idmac_read_icreg(ipu, IDMAC_CHA_EN),
                idmac_read_icreg(ipu, IDMAC_CHA_PRI),
                idmac_read_icreg(ipu, IDMAC_CHA_BUSY));
        dev_dbg(ipu->dev, "BUF0_RDY 0x%x, BUF1_RDY 0x%x, CUR_BUF 0x%x, "
                "DB_MODE 0x%x, TASKS_STAT 0x%x\n",
                idmac_read_ipureg(ipu, IPU_CHA_BUF0_RDY),
                idmac_read_ipureg(ipu, IPU_CHA_BUF1_RDY),
                idmac_read_ipureg(ipu, IPU_CHA_CUR_BUF),
                idmac_read_ipureg(ipu, IPU_CHA_DB_MODE_SEL),
                idmac_read_ipureg(ipu, IPU_TASKS_STAT));
}

static uint32_t bytes_per_pixel(enum pixel_fmt fmt)
{
        switch (fmt) {
        case IPU_PIX_FMT_GENERIC:       /* generic data */
        case IPU_PIX_FMT_RGB332:
        case IPU_PIX_FMT_YUV420P:
        case IPU_PIX_FMT_YUV422P:
        default:
                return 1;
        case IPU_PIX_FMT_RGB565:
        case IPU_PIX_FMT_YUYV:
        case IPU_PIX_FMT_UYVY:
                return 2;
        case IPU_PIX_FMT_BGR24:
        case IPU_PIX_FMT_RGB24:
                return 3;
        case IPU_PIX_FMT_GENERIC_32:    /* generic data */
        case IPU_PIX_FMT_BGR32:
        case IPU_PIX_FMT_RGB32:
        case IPU_PIX_FMT_ABGR32:
                return 4;
        }
}

/* Enable direct write to memory by the Camera Sensor Interface */
static void ipu_ic_enable_task(struct ipu *ipu, enum ipu_channel channel)
{
        uint32_t ic_conf, mask;

        switch (channel) {
        case IDMAC_IC_0:
                mask = IC_CONF_PRPENC_EN;
                break;
        case IDMAC_IC_7:
                mask = IC_CONF_RWS_EN | IC_CONF_PRPENC_EN;
                break;
        default:
                return;
        }
        ic_conf = idmac_read_icreg(ipu, IC_CONF) | mask;
        idmac_write_icreg(ipu, ic_conf, IC_CONF);
}

/* Called under spin_lock_irqsave(&ipu_data.lock) */
static void ipu_ic_disable_task(struct ipu *ipu, enum ipu_channel channel)
{
        uint32_t ic_conf, mask;

        switch (channel) {
        case IDMAC_IC_0:
                mask = IC_CONF_PRPENC_EN;
                break;
        case IDMAC_IC_7:
                mask = IC_CONF_RWS_EN | IC_CONF_PRPENC_EN;
                break;
        default:
                return;
        }
        ic_conf = idmac_read_icreg(ipu, IC_CONF) & ~mask;
        idmac_write_icreg(ipu, ic_conf, IC_CONF);
}

static uint32_t ipu_channel_status(struct ipu *ipu, enum ipu_channel channel)
{
        uint32_t stat = TASK_STAT_IDLE;
        uint32_t task_stat_reg = idmac_read_ipureg(ipu, IPU_TASKS_STAT);

        switch (channel) {
        case IDMAC_IC_7:
                stat = (task_stat_reg & TSTAT_CSI2MEM_MASK) >>
                        TSTAT_CSI2MEM_OFFSET;
                break;
        case IDMAC_IC_0:
        case IDMAC_SDC_0:
        case IDMAC_SDC_1:
        default:
                break;
        }
        return stat;
}

struct chan_param_mem_planar {
        /* Word 0 */
        u32     xv:10;
        u32     yv:10;
        u32     xb:12;

        u32     yb:12;
        u32     res1:2;
        u32     nsb:1;
        u32     lnpb:6;
        u32     ubo_l:11;

        u32     ubo_h:15;
        u32     vbo_l:17;

        u32     vbo_h:9;
        u32     res2:3;
        u32     fw:12;
        u32     fh_l:8;

        u32     fh_h:4;
        u32     res3:28;

        /* Word 1 */
        u32     eba0;

        u32     eba1;

        u32     bpp:3;
        u32     sl:14;
        u32     pfs:3;
        u32     bam:3;
        u32     res4:2;
        u32     npb:6;
        u32     res5:1;

        u32     sat:2;
        u32     res6:30;
} __attribute__ ((packed));

struct chan_param_mem_interleaved {
        /* Word 0 */
        u32     xv:10;
        u32     yv:10;
        u32     xb:12;

        u32     yb:12;
        u32     sce:1;
        u32     res1:1;
        u32     nsb:1;
        u32     lnpb:6;
        u32     sx:10;
        u32     sy_l:1;

        u32     sy_h:9;
        u32     ns:10;
        u32     sm:10;
        u32     sdx_l:3;

        u32     sdx_h:2;
        u32     sdy:5;
        u32     sdrx:1;
        u32     sdry:1;
        u32     sdr1:1;
        u32     res2:2;
        u32     fw:12;
        u32     fh_l:8;

        u32     fh_h:4;
        u32     res3:28;

        /* Word 1 */
        u32     eba0;

        u32     eba1;

        u32     bpp:3;
        u32     sl:14;
        u32     pfs:3;
        u32     bam:3;
        u32     res4:2;
        u32     npb:6;
        u32     res5:1;

        u32     sat:2;
        u32     scc:1;
        u32     ofs0:5;
        u32     ofs1:5;
        u32     ofs2:5;
        u32     ofs3:5;
        u32     wid0:3;
        u32     wid1:3;
        u32     wid2:3;

        u32     wid3:3;
        u32     dec_sel:1;
        u32     res6:28;
} __attribute__ ((packed));

union chan_param_mem {
        struct chan_param_mem_planar            pp;
        struct chan_param_mem_interleaved       ip;
};

static void ipu_ch_param_set_plane_offset(union chan_param_mem *params,
                                          u32 u_offset, u32 v_offset)
{
        params->pp.ubo_l = u_offset & 0x7ff;
        params->pp.ubo_h = u_offset >> 11;
        params->pp.vbo_l = v_offset & 0x1ffff;
        params->pp.vbo_h = v_offset >> 17;
}

static void ipu_ch_param_set_size(union chan_param_mem *params,
                                  uint32_t pixel_fmt, uint16_t width,
                                  uint16_t height, uint16_t stride)
{
        u32 u_offset;
        u32 v_offset;

        params->pp.fw           = width - 1;
        params->pp.fh_l         = height - 1;
        params->pp.fh_h         = (height - 1) >> 8;
        params->pp.sl           = stride - 1;

        switch (pixel_fmt) {
        case IPU_PIX_FMT_GENERIC:
                /*Represents 8-bit Generic data */
                params->pp.bpp  = 3;
                params->pp.pfs  = 7;
                params->pp.npb  = 31;
                params->pp.sat  = 2;            /* SAT = use 32-bit access */
                break;
        case IPU_PIX_FMT_GENERIC_32:
                /*Represents 32-bit Generic data */
                params->pp.bpp  = 0;
                params->pp.pfs  = 7;
                params->pp.npb  = 7;
                params->pp.sat  = 2;            /* SAT = use 32-bit access */
                break;
        case IPU_PIX_FMT_RGB565:
                params->ip.bpp  = 2;
                params->ip.pfs  = 4;
                params->ip.npb  = 15;
                params->ip.sat  = 2;            /* SAT = 32-bit access */
                params->ip.ofs0 = 0;            /* Red bit offset */
                params->ip.ofs1 = 5;            /* Green bit offset */
                params->ip.ofs2 = 11;           /* Blue bit offset */
                params->ip.ofs3 = 16;           /* Alpha bit offset */
                params->ip.wid0 = 4;            /* Red bit width - 1 */
                params->ip.wid1 = 5;            /* Green bit width - 1 */
                params->ip.wid2 = 4;            /* Blue bit width - 1 */
                break;
        case IPU_PIX_FMT_BGR24:
                params->ip.bpp  = 1;            /* 24 BPP & RGB PFS */
                params->ip.pfs  = 4;
                params->ip.npb  = 7;
                params->ip.sat  = 2;            /* SAT = 32-bit access */
                params->ip.ofs0 = 0;            /* Red bit offset */
                params->ip.ofs1 = 8;            /* Green bit offset */
                params->ip.ofs2 = 16;           /* Blue bit offset */
                params->ip.ofs3 = 24;           /* Alpha bit offset */
                params->ip.wid0 = 7;            /* Red bit width - 1 */
                params->ip.wid1 = 7;            /* Green bit width - 1 */
                params->ip.wid2 = 7;            /* Blue bit width - 1 */
                break;
        case IPU_PIX_FMT_RGB24:
                params->ip.bpp  = 1;            /* 24 BPP & RGB PFS */
                params->ip.pfs  = 4;
                params->ip.npb  = 7;
                params->ip.sat  = 2;            /* SAT = 32-bit access */
                params->ip.ofs0 = 16;           /* Red bit offset */
                params->ip.ofs1 = 8;            /* Green bit offset */
                params->ip.ofs2 = 0;            /* Blue bit offset */
                params->ip.ofs3 = 24;           /* Alpha bit offset */
                params->ip.wid0 = 7;            /* Red bit width - 1 */
                params->ip.wid1 = 7;            /* Green bit width - 1 */
                params->ip.wid2 = 7;            /* Blue bit width - 1 */
                break;
        case IPU_PIX_FMT_BGRA32:
        case IPU_PIX_FMT_BGR32:
        case IPU_PIX_FMT_ABGR32:
                params->ip.bpp  = 0;
                params->ip.pfs  = 4;
                params->ip.npb  = 7;
                params->ip.sat  = 2;            /* SAT = 32-bit access */
                params->ip.ofs0 = 8;            /* Red bit offset */
                params->ip.ofs1 = 16;           /* Green bit offset */
                params->ip.ofs2 = 24;           /* Blue bit offset */
                params->ip.ofs3 = 0;            /* Alpha bit offset */
                params->ip.wid0 = 7;            /* Red bit width - 1 */
                params->ip.wid1 = 7;            /* Green bit width - 1 */
                params->ip.wid2 = 7;            /* Blue bit width - 1 */
                params->ip.wid3 = 7;            /* Alpha bit width - 1 */
                break;
        case IPU_PIX_FMT_RGBA32:
        case IPU_PIX_FMT_RGB32:
                params->ip.bpp  = 0;
                params->ip.pfs  = 4;
                params->ip.npb  = 7;
                params->ip.sat  = 2;            /* SAT = 32-bit access */
                params->ip.ofs0 = 24;           /* Red bit offset */
                params->ip.ofs1 = 16;           /* Green bit offset */
                params->ip.ofs2 = 8;            /* Blue bit offset */
                params->ip.ofs3 = 0;            /* Alpha bit offset */
                params->ip.wid0 = 7;            /* Red bit width - 1 */
                params->ip.wid1 = 7;            /* Green bit width - 1 */
                params->ip.wid2 = 7;            /* Blue bit width - 1 */
                params->ip.wid3 = 7;            /* Alpha bit width - 1 */
                break;
        case IPU_PIX_FMT_UYVY:
                params->ip.bpp  = 2;
                params->ip.pfs  = 6;
                params->ip.npb  = 7;
                params->ip.sat  = 2;            /* SAT = 32-bit access */
                break;
        case IPU_PIX_FMT_YUV420P2:
        case IPU_PIX_FMT_YUV420P:
                params->ip.bpp  = 3;
                params->ip.pfs  = 3;
                params->ip.npb  = 7;
                params->ip.sat  = 2;            /* SAT = 32-bit access */
                u_offset = stride * height;
                v_offset = u_offset + u_offset / 4;
                ipu_ch_param_set_plane_offset(params, u_offset, v_offset);
                break;
        case IPU_PIX_FMT_YVU422P:
                params->ip.bpp  = 3;
                params->ip.pfs  = 2;
                params->ip.npb  = 7;
                params->ip.sat  = 2;            /* SAT = 32-bit access */
                v_offset = stride * height;
                u_offset = v_offset + v_offset / 2;
                ipu_ch_param_set_plane_offset(params, u_offset, v_offset);
                break;
        case IPU_PIX_FMT_YUV422P:
                params->ip.bpp  = 3;
                params->ip.pfs  = 2;
                params->ip.npb  = 7;
                params->ip.sat  = 2;            /* SAT = 32-bit access */
                u_offset = stride * height;
                v_offset = u_offset + u_offset / 2;
                ipu_ch_param_set_plane_offset(params, u_offset, v_offset);
                break;
        default:
                dev_err(ipu_data.dev,
                        "mx3 ipu: unimplemented pixel format %d\n", pixel_fmt);
                break;
        }

        params->pp.nsb = 1;
}

static void ipu_ch_param_set_buffer(union chan_param_mem *params,
                                    dma_addr_t buf0, dma_addr_t buf1)
{
        params->pp.eba0 = buf0;
        params->pp.eba1 = buf1;
}

static void ipu_ch_param_set_rotation(union chan_param_mem *params,
                                      enum ipu_rotate_mode rotate)
{
        params->pp.bam = rotate;
}

static void ipu_write_param_mem(uint32_t addr, uint32_t *data,
                                uint32_t num_words)
{
        for (; num_words > 0; num_words--) {
                dev_dbg(ipu_data.dev,
                        "write param mem - addr = 0x%08X, data = 0x%08X\n",
                        addr, *data);
                idmac_write_ipureg(&ipu_data, addr, IPU_IMA_ADDR);
                idmac_write_ipureg(&ipu_data, *data++, IPU_IMA_DATA);
                addr++;
                if ((addr & 0x7) == 5) {
                        addr &= ~0x7;   /* set to word 0 */
                        addr += 8;      /* increment to next row */
                }
        }
}

static int calc_resize_coeffs(uint32_t in_size, uint32_t out_size,
                              uint32_t *resize_coeff,
                              uint32_t *downsize_coeff)
{
        uint32_t temp_size;
        uint32_t temp_downsize;

        *resize_coeff   = 1 << 13;
        *downsize_coeff = 1 << 13;

        /* Cannot downsize more than 8:1 */
        if (out_size << 3 < in_size)
                return -EINVAL;

        /* compute downsizing coefficient */
        temp_downsize = 0;
        temp_size = in_size;
        while (temp_size >= out_size * 2 && temp_downsize < 2) {
                temp_size >>= 1;
                temp_downsize++;
        }
        *downsize_coeff = temp_downsize;

        /*
         * compute resizing coefficient using the following formula:
         * resize_coeff = M*(SI -1)/(SO - 1)
         * where M = 2^13, SI - input size, SO - output size
         */
        *resize_coeff = (8192L * (temp_size - 1)) / (out_size - 1);
        if (*resize_coeff >= 16384L) {
                dev_err(ipu_data.dev, "Warning! Overflow on resize coeff.\n");
                *resize_coeff = 0x3FFF;
        }

        dev_dbg(ipu_data.dev, "resizing from %u -> %u pixels, "
                "downsize=%u, resize=%u.%lu (reg=%u)\n", in_size, out_size,
                *downsize_coeff, *resize_coeff >= 8192L ? 1 : 0,
                ((*resize_coeff & 0x1FFF) * 10000L) / 8192L, *resize_coeff);

        return 0;
}

static enum ipu_color_space format_to_colorspace(enum pixel_fmt fmt)
{
        switch (fmt) {
        case IPU_PIX_FMT_RGB565:
        case IPU_PIX_FMT_BGR24:
        case IPU_PIX_FMT_RGB24:
        case IPU_PIX_FMT_BGR32:
        case IPU_PIX_FMT_RGB32:
                return IPU_COLORSPACE_RGB;
        default:
                return IPU_COLORSPACE_YCBCR;
        }
}

static int ipu_ic_init_prpenc(struct ipu *ipu,
                              union ipu_channel_param *params, bool src_is_csi)
{
        uint32_t reg, ic_conf;
        uint32_t downsize_coeff, resize_coeff;
        enum ipu_color_space in_fmt, out_fmt;

        /* Setup vertical resizing */
        calc_resize_coeffs(params->video.in_height,
                            params->video.out_height,
                            &resize_coeff, &downsize_coeff);
        reg = (downsize_coeff << 30) | (resize_coeff << 16);

        /* Setup horizontal resizing */
        calc_resize_coeffs(params->video.in_width,
                            params->video.out_width,
                            &resize_coeff, &downsize_coeff);
        reg |= (downsize_coeff << 14) | resize_coeff;

        /* Setup color space conversion */
        in_fmt = format_to_colorspace(params->video.in_pixel_fmt);
        out_fmt = format_to_colorspace(params->video.out_pixel_fmt);

        /*
         * Colourspace conversion unsupported yet - see _init_csc() in
         * Freescale sources
         */
        if (in_fmt != out_fmt) {
                dev_err(ipu->dev, "Colourspace conversion unsupported!\n");
                return -EOPNOTSUPP;
        }

        idmac_write_icreg(ipu, reg, IC_PRP_ENC_RSC);

        ic_conf = idmac_read_icreg(ipu, IC_CONF);

        if (src_is_csi)
                ic_conf &= ~IC_CONF_RWS_EN;
        else
                ic_conf |= IC_CONF_RWS_EN;

        idmac_write_icreg(ipu, ic_conf, IC_CONF);

        return 0;
}

static uint32_t dma_param_addr(uint32_t dma_ch)
{
        /* Channel Parameter Memory */
        return 0x10000 | (dma_ch << 4);
}

static void ipu_channel_set_priority(struct ipu *ipu, enum ipu_channel channel,
                                     bool prio)
{
        u32 reg = idmac_read_icreg(ipu, IDMAC_CHA_PRI);

        if (prio)
                reg |= 1UL << channel;
        else
                reg &= ~(1UL << channel);

        idmac_write_icreg(ipu, reg, IDMAC_CHA_PRI);

        dump_idmac_reg(ipu);
}

static uint32_t ipu_channel_conf_mask(enum ipu_channel channel)
{
        uint32_t mask;

        switch (channel) {
        case IDMAC_IC_0:
        case IDMAC_IC_7:
                mask = IPU_CONF_CSI_EN | IPU_CONF_IC_EN;
                break;
        case IDMAC_SDC_0:
        case IDMAC_SDC_1:
                mask = IPU_CONF_SDC_EN | IPU_CONF_DI_EN;
                break;
        default:
                mask = 0;
                break;
        }

        return mask;
}

/**
 * ipu_enable_channel() - enable an IPU channel.
 * @idmac:      IPU DMAC context.
 * @ichan:      IDMAC channel.
 * @return:     0 on success or negative error code on failure.
 */
static int ipu_enable_channel(struct idmac *idmac, struct idmac_channel *ichan)
{
        struct ipu *ipu = to_ipu(idmac);
        enum ipu_channel channel = ichan->dma_chan.chan_id;
        uint32_t reg;
        unsigned long flags;

        spin_lock_irqsave(&ipu->lock, flags);

        /* Reset to buffer 0 */
        idmac_write_ipureg(ipu, 1UL << channel, IPU_CHA_CUR_BUF);
        ichan->active_buffer = 0;
        ichan->status = IPU_CHANNEL_ENABLED;

        switch (channel) {
        case IDMAC_SDC_0:
        case IDMAC_SDC_1:
        case IDMAC_IC_7:
                ipu_channel_set_priority(ipu, channel, true);
        default:
                break;
        }

        reg = idmac_read_icreg(ipu, IDMAC_CHA_EN);

        idmac_write_icreg(ipu, reg | (1UL << channel), IDMAC_CHA_EN);

        ipu_ic_enable_task(ipu, channel);

        spin_unlock_irqrestore(&ipu->lock, flags);
        return 0;
}

/**
 * ipu_init_channel_buffer() - initialize a buffer for logical IPU channel.
 * @ichan:      IDMAC channel.
 * @pixel_fmt:  pixel format of buffer. Pixel format is a FOURCC ASCII code.
 * @width:      width of buffer in pixels.
 * @height:     height of buffer in pixels.
 * @stride:     stride length of buffer in pixels.
 * @rot_mode:   rotation mode of buffer. A rotation setting other than
 *              IPU_ROTATE_VERT_FLIP should only be used for input buffers of
 *              rotation channels.
 * @phyaddr_0:  buffer 0 physical address.
 * @phyaddr_1:  buffer 1 physical address. Setting this to a value other than
 *              NULL enables double buffering mode.
 * @return:     0 on success or negative error code on failure.
 */
static int ipu_init_channel_buffer(struct idmac_channel *ichan,
                                   enum pixel_fmt pixel_fmt,
                                   uint16_t width, uint16_t height,
                                   uint32_t stride,
                                   enum ipu_rotate_mode rot_mode,
                                   dma_addr_t phyaddr_0, dma_addr_t phyaddr_1)
{
        enum ipu_channel channel = ichan->dma_chan.chan_id;
        struct idmac *idmac = to_idmac(ichan->dma_chan.device);
        struct ipu *ipu = to_ipu(idmac);
        union chan_param_mem params = {};
        unsigned long flags;
        uint32_t reg;
        uint32_t stride_bytes;

        stride_bytes = stride * bytes_per_pixel(pixel_fmt);

        if (stride_bytes % 4) {
                dev_err(ipu->dev,
                        "Stride length must be 32-bit aligned, stride = %d, bytes = %d\n",
                        stride, stride_bytes);
                return -EINVAL;
        }

        /* IC channel's stride must be a multiple of 8 pixels */
        if ((channel <= IDMAC_IC_13) && (stride % 8)) {
                dev_err(ipu->dev, "Stride must be 8 pixel multiple\n");
                return -EINVAL;
        }

        /* Build parameter memory data for DMA channel */
        ipu_ch_param_set_size(&params, pixel_fmt, width, height, stride_bytes);
        ipu_ch_param_set_buffer(&params, phyaddr_0, phyaddr_1);
        ipu_ch_param_set_rotation(&params, rot_mode);

        spin_lock_irqsave(&ipu->lock, flags);

        ipu_write_param_mem(dma_param_addr(channel), (uint32_t *)&params, 10);

        reg = idmac_read_ipureg(ipu, IPU_CHA_DB_MODE_SEL);

        if (phyaddr_1)
                reg |= 1UL << channel;
        else
                reg &= ~(1UL << channel);

        idmac_write_ipureg(ipu, reg, IPU_CHA_DB_MODE_SEL);

        ichan->status = IPU_CHANNEL_READY;

        spin_unlock_irqrestore(&ipu->lock, flags);

        return 0;
}

/**
 * ipu_select_buffer() - mark a channel's buffer as ready.
 * @channel:    channel ID.
 * @buffer_n:   buffer number to mark ready.
 */
static void ipu_select_buffer(enum ipu_channel channel, int buffer_n)
{
        /* No locking - this is a write-one-to-set register, cleared by IPU */
        if (buffer_n == 0)
                /* Mark buffer 0 as ready. */
                idmac_write_ipureg(&ipu_data, 1UL << channel, IPU_CHA_BUF0_RDY);
        else
                /* Mark buffer 1 as ready. */
                idmac_write_ipureg(&ipu_data, 1UL << channel, IPU_CHA_BUF1_RDY);
}

/**
 * ipu_update_channel_buffer() - update physical address of a channel buffer.
 * @ichan:      IDMAC channel.
 * @buffer_n:   buffer number to update.
 *              0 or 1 are the only valid values.
 * @phyaddr:    buffer physical address.
 */
/* Called under spin_lock(_irqsave)(&ichan->lock) */
static void ipu_update_channel_buffer(struct idmac_channel *ichan,
                                      int buffer_n, dma_addr_t phyaddr)
{
        enum ipu_channel channel = ichan->dma_chan.chan_id;
        uint32_t reg;
        unsigned long flags;

        spin_lock_irqsave(&ipu_data.lock, flags);

        if (buffer_n == 0) {
                reg = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF0_RDY);
                if (reg & (1UL << channel)) {
                        ipu_ic_disable_task(&ipu_data, channel);
                        ichan->status = IPU_CHANNEL_READY;
                }

                /* 44.3.3.1.9 - Row Number 1 (WORD1, offset 0) */
                idmac_write_ipureg(&ipu_data, dma_param_addr(channel) +
                                   0x0008UL, IPU_IMA_ADDR);
                idmac_write_ipureg(&ipu_data, phyaddr, IPU_IMA_DATA);
        } else {
                reg = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF1_RDY);
                if (reg & (1UL << channel)) {
                        ipu_ic_disable_task(&ipu_data, channel);
                        ichan->status = IPU_CHANNEL_READY;
                }

                /* Check if double-buffering is already enabled */
                reg = idmac_read_ipureg(&ipu_data, IPU_CHA_DB_MODE_SEL);

                if (!(reg & (1UL << channel)))
                        idmac_write_ipureg(&ipu_data, reg | (1UL << channel),
                                           IPU_CHA_DB_MODE_SEL);

                /* 44.3.3.1.9 - Row Number 1 (WORD1, offset 1) */
                idmac_write_ipureg(&ipu_data, dma_param_addr(channel) +
                                   0x0009UL, IPU_IMA_ADDR);
                idmac_write_ipureg(&ipu_data, phyaddr, IPU_IMA_DATA);
        }

        spin_unlock_irqrestore(&ipu_data.lock, flags);
}

/* Called under spin_lock_irqsave(&ichan->lock) */
static int ipu_submit_buffer(struct idmac_channel *ichan,
        struct idmac_tx_desc *desc, struct scatterlist *sg, int buf_idx)
{
        unsigned int chan_id = ichan->dma_chan.chan_id;
        struct device *dev = &ichan->dma_chan.dev->device;

        if (async_tx_test_ack(&desc->txd))
                return -EINTR;

        /*
         * On first invocation this shouldn't be necessary, the call to
         * ipu_init_channel_buffer() above will set addresses for us, so we
         * could make it conditional on status >= IPU_CHANNEL_ENABLED, but
         * doing it again shouldn't hurt either.
         */
        ipu_update_channel_buffer(ichan, buf_idx, sg_dma_address(sg));

        ipu_select_buffer(chan_id, buf_idx);
        dev_dbg(dev, "Updated sg %p on channel 0x%x buffer %d\n",
                sg, chan_id, buf_idx);

        return 0;
}

/* Called under spin_lock_irqsave(&ichan->lock) */
static int ipu_submit_channel_buffers(struct idmac_channel *ichan,
                                      struct idmac_tx_desc *desc)
{
        struct scatterlist *sg;
        int i, ret = 0;

        for (i = 0, sg = desc->sg; i < 2 && sg; i++) {
                if (!ichan->sg[i]) {
                        ichan->sg[i] = sg;

                        ret = ipu_submit_buffer(ichan, desc, sg, i);
                        if (ret < 0)
                                return ret;

                        sg = sg_next(sg);
                }
        }

        return ret;
}

static dma_cookie_t idmac_tx_submit(struct dma_async_tx_descriptor *tx)
{
        struct idmac_tx_desc *desc = to_tx_desc(tx);
        struct idmac_channel *ichan = to_idmac_chan(tx->chan);
        struct idmac *idmac = to_idmac(tx->chan->device);
        struct ipu *ipu = to_ipu(idmac);
        struct device *dev = &ichan->dma_chan.dev->device;
        dma_cookie_t cookie;
        unsigned long flags;
        int ret;

        /* Sanity check */
        if (!list_empty(&desc->list)) {
                /* The descriptor doesn't belong to client */
                dev_err(dev, "Descriptor %p not prepared!\n", tx);
                return -EBUSY;
        }

        mutex_lock(&ichan->chan_mutex);

        async_tx_clear_ack(tx);

        if (ichan->status < IPU_CHANNEL_READY) {
                struct idmac_video_param *video = &ichan->params.video;
                /*
                 * Initial buffer assignment - the first two sg-entries from
                 * the descriptor will end up in the IDMAC buffers
                 */
                dma_addr_t dma_1 = sg_is_last(desc->sg) ? 0 :
                        sg_dma_address(&desc->sg[1]);

                WARN_ON(ichan->sg[0] || ichan->sg[1]);

                cookie = ipu_init_channel_buffer(ichan,
                                                 video->out_pixel_fmt,
                                                 video->out_width,
                                                 video->out_height,
                                                 video->out_stride,
                                                 IPU_ROTATE_NONE,
                                                 sg_dma_address(&desc->sg[0]),
                                                 dma_1);
                if (cookie < 0)
                        goto out;
        }

        dev_dbg(dev, "Submitting sg %p\n", &desc->sg[0]);

        cookie = dma_cookie_assign(tx);

        /* ipu->lock can be taken under ichan->lock, but not v.v. */
        spin_lock_irqsave(&ichan->lock, flags);

        list_add_tail(&desc->list, &ichan->queue);
        /* submit_buffers() atomically verifies and fills empty sg slots */
        ret = ipu_submit_channel_buffers(ichan, desc);

        spin_unlock_irqrestore(&ichan->lock, flags);

        if (ret < 0) {
                cookie = ret;
                goto dequeue;
        }

        if (ichan->status < IPU_CHANNEL_ENABLED) {
                ret = ipu_enable_channel(idmac, ichan);
                if (ret < 0) {
                        cookie = ret;
                        goto dequeue;
                }
        }

        dump_idmac_reg(ipu);

dequeue:
        if (cookie < 0) {
                spin_lock_irqsave(&ichan->lock, flags);
                list_del_init(&desc->list);
                spin_unlock_irqrestore(&ichan->lock, flags);
                tx->cookie = cookie;
                ichan->dma_chan.cookie = cookie;
        }

out:
        mutex_unlock(&ichan->chan_mutex);

        return cookie;
}

/* Called with ichan->chan_mutex held */
static int idmac_desc_alloc(struct idmac_channel *ichan, int n)
{
        struct idmac_tx_desc *desc = vmalloc(n * sizeof(struct idmac_tx_desc));
        struct idmac *idmac = to_idmac(ichan->dma_chan.device);

        if (!desc)
                return -ENOMEM;

        /* No interrupts, just disable the tasklet for a moment */
        tasklet_disable(&to_ipu(idmac)->tasklet);

        ichan->n_tx_desc = n;
        ichan->desc = desc;
        INIT_LIST_HEAD(&ichan->queue);
        INIT_LIST_HEAD(&ichan->free_list);

        while (n--) {
                struct dma_async_tx_descriptor *txd = &desc->txd;

                memset(txd, 0, sizeof(*txd));
                dma_async_tx_descriptor_init(txd, &ichan->dma_chan);
                txd->tx_submit          = idmac_tx_submit;

                list_add(&desc->list, &ichan->free_list);

                desc++;
        }

        tasklet_enable(&to_ipu(idmac)->tasklet);

        return 0;
}

/**
 * ipu_init_channel() - initialize an IPU channel.
 * @idmac:      IPU DMAC context.
 * @ichan:      pointer to the channel object.
 * @return      0 on success or negative error code on failure.
 */
static int ipu_init_channel(struct idmac *idmac, struct idmac_channel *ichan)
{
        union ipu_channel_param *params = &ichan->params;
        uint32_t ipu_conf;
        enum ipu_channel channel = ichan->dma_chan.chan_id;
        unsigned long flags;
        uint32_t reg;
        struct ipu *ipu = to_ipu(idmac);
        int ret = 0, n_desc = 0;

        dev_dbg(ipu->dev, "init channel = %d\n", channel);

        if (channel != IDMAC_SDC_0 && channel != IDMAC_SDC_1 &&
            channel != IDMAC_IC_7)
                return -EINVAL;

        spin_lock_irqsave(&ipu->lock, flags);

        switch (channel) {
        case IDMAC_IC_7:
                n_desc = 16;
                reg = idmac_read_icreg(ipu, IC_CONF);
                idmac_write_icreg(ipu, reg & ~IC_CONF_CSI_MEM_WR_EN, IC_CONF);
                break;
        case IDMAC_IC_0:
                n_desc = 16;
                reg = idmac_read_ipureg(ipu, IPU_FS_PROC_FLOW);
                idmac_write_ipureg(ipu, reg & ~FS_ENC_IN_VALID, IPU_FS_PROC_FLOW);
                ret = ipu_ic_init_prpenc(ipu, params, true);
                break;
        case IDMAC_SDC_0:
        case IDMAC_SDC_1:
                n_desc = 4;
        default:
                break;
        }

        ipu->channel_init_mask |= 1L << channel;

        /* Enable IPU sub module */
        ipu_conf = idmac_read_ipureg(ipu, IPU_CONF) |
                ipu_channel_conf_mask(channel);
        idmac_write_ipureg(ipu, ipu_conf, IPU_CONF);

        spin_unlock_irqrestore(&ipu->lock, flags);

        if (n_desc && !ichan->desc)
                ret = idmac_desc_alloc(ichan, n_desc);

        dump_idmac_reg(ipu);

        return ret;
}

/**
 * ipu_uninit_channel() - uninitialize an IPU channel.
 * @idmac:      IPU DMAC context.
 * @ichan:      pointer to the channel object.
 */
static void ipu_uninit_channel(struct idmac *idmac, struct idmac_channel *ichan)
{
        enum ipu_channel channel = ichan->dma_chan.chan_id;
        unsigned long flags;
        uint32_t reg;
        unsigned long chan_mask = 1UL << channel;
        uint32_t ipu_conf;
        struct ipu *ipu = to_ipu(idmac);

        spin_lock_irqsave(&ipu->lock, flags);

        if (!(ipu->channel_init_mask & chan_mask)) {
                dev_err(ipu->dev, "Channel already uninitialized %d\n",
                        channel);
                spin_unlock_irqrestore(&ipu->lock, flags);
                return;
        }

        /* Reset the double buffer */
        reg = idmac_read_ipureg(ipu, IPU_CHA_DB_MODE_SEL);
        idmac_write_ipureg(ipu, reg & ~chan_mask, IPU_CHA_DB_MODE_SEL);

        ichan->sec_chan_en = false;

        switch (channel) {
        case IDMAC_IC_7:
                reg = idmac_read_icreg(ipu, IC_CONF);
                idmac_write_icreg(ipu, reg & ~(IC_CONF_RWS_EN | IC_CONF_PRPENC_EN),
                             IC_CONF);
                break;
        case IDMAC_IC_0:
                reg = idmac_read_icreg(ipu, IC_CONF);
                idmac_write_icreg(ipu, reg & ~(IC_CONF_PRPENC_EN | IC_CONF_PRPENC_CSC1),
                                  IC_CONF);
                break;
        case IDMAC_SDC_0:
        case IDMAC_SDC_1:
        default:
                break;
        }

        ipu->channel_init_mask &= ~(1L << channel);

        ipu_conf = idmac_read_ipureg(ipu, IPU_CONF) &
                ~ipu_channel_conf_mask(channel);
        idmac_write_ipureg(ipu, ipu_conf, IPU_CONF);

        spin_unlock_irqrestore(&ipu->lock, flags);

        ichan->n_tx_desc = 0;
        vfree(ichan->desc);
        ichan->desc = NULL;
}

/**
 * ipu_disable_channel() - disable an IPU channel.
 * @idmac:              IPU DMAC context.
 * @ichan:              channel object pointer.
 * @wait_for_stop:      flag to set whether to wait for channel end of frame or
 *                      return immediately.
 * @return:             0 on success or negative error code on failure.
 */
static int ipu_disable_channel(struct idmac *idmac, struct idmac_channel *ichan,
                               bool wait_for_stop)
{
        enum ipu_channel channel = ichan->dma_chan.chan_id;
        struct ipu *ipu = to_ipu(idmac);
        uint32_t reg;
        unsigned long flags;
        unsigned long chan_mask = 1UL << channel;
        unsigned int timeout;

        if (wait_for_stop && channel != IDMAC_SDC_1 && channel != IDMAC_SDC_0) {
                timeout = 40;
                /* This waiting always fails. Related to spurious irq problem */
                while ((idmac_read_icreg(ipu, IDMAC_CHA_BUSY) & chan_mask) ||
                       (ipu_channel_status(ipu, channel) == TASK_STAT_ACTIVE)) {
                        timeout--;
                        msleep(10);

                        if (!timeout) {
                                dev_dbg(ipu->dev,
                                        "Warning: timeout waiting for channel %u to "
                                        "stop: buf0_rdy = 0x%08X, buf1_rdy = 0x%08X, "
                                        "busy = 0x%08X, tstat = 0x%08X\n", channel,
                                        idmac_read_ipureg(ipu, IPU_CHA_BUF0_RDY),
                                        idmac_read_ipureg(ipu, IPU_CHA_BUF1_RDY),
                                        idmac_read_icreg(ipu, IDMAC_CHA_BUSY),
                                        idmac_read_ipureg(ipu, IPU_TASKS_STAT));
                                break;
                        }
                }
                dev_dbg(ipu->dev, "timeout = %d * 10ms\n", 40 - timeout);
        }
        /* SDC BG and FG must be disabled before DMA is disabled */
        if (wait_for_stop && (channel == IDMAC_SDC_0 ||
                              channel == IDMAC_SDC_1)) {
                for (timeout = 5;
                     timeout && !ipu_irq_status(ichan->eof_irq); timeout--)
                        msleep(5);
        }

        spin_lock_irqsave(&ipu->lock, flags);

        /* Disable IC task */
        ipu_ic_disable_task(ipu, channel);

        /* Disable DMA channel(s) */
        reg = idmac_read_icreg(ipu, IDMAC_CHA_EN);
        idmac_write_icreg(ipu, reg & ~chan_mask, IDMAC_CHA_EN);

        spin_unlock_irqrestore(&ipu->lock, flags);

        return 0;
}

static struct scatterlist *idmac_sg_next(struct idmac_channel *ichan,
        struct idmac_tx_desc **desc, struct scatterlist *sg)
{
        struct scatterlist *sgnew = sg ? sg_next(sg) : NULL;

        if (sgnew)
                /* next sg-element in this list */
                return sgnew;

        if ((*desc)->list.next == &ichan->queue)
                /* No more descriptors on the queue */
                return NULL;

        /* Fetch next descriptor */
        *desc = list_entry((*desc)->list.next, struct idmac_tx_desc, list);
        return (*desc)->sg;
}

/*
 * We have several possibilities here:
 * current BUF          next BUF
 *
 * not last sg          next not last sg
 * not last sg          next last sg
 * last sg              first sg from next descriptor
 * last sg              NULL
 *
 * Besides, the descriptor queue might be empty or not. We process all these
 * cases carefully.
 */
static irqreturn_t idmac_interrupt(int irq, void *dev_id)
{
        struct idmac_channel *ichan = dev_id;
        struct device *dev = &ichan->dma_chan.dev->device;
        unsigned int chan_id = ichan->dma_chan.chan_id;
        struct scatterlist **sg, *sgnext, *sgnew = NULL;
        /* Next transfer descriptor */
        struct idmac_tx_desc *desc, *descnew;
        dma_async_tx_callback callback;
        void *callback_param;
        bool done = false;
        u32 ready0, ready1, curbuf, err;
        unsigned long flags;

        /* IDMAC has cleared the respective BUFx_RDY bit, we manage the buffer */

        dev_dbg(dev, "IDMAC irq %d, buf %d\n", irq, ichan->active_buffer);

        spin_lock_irqsave(&ipu_data.lock, flags);

        ready0  = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF0_RDY);
        ready1  = idmac_read_ipureg(&ipu_data, IPU_CHA_BUF1_RDY);
        curbuf  = idmac_read_ipureg(&ipu_data, IPU_CHA_CUR_BUF);
        err     = idmac_read_ipureg(&ipu_data, IPU_INT_STAT_4);

        if (err & (1 << chan_id)) {
                idmac_write_ipureg(&ipu_data, 1 << chan_id, IPU_INT_STAT_4);
                spin_unlock_irqrestore(&ipu_data.lock, flags);
                /*
                 * Doing this
                 * ichan->sg[0] = ichan->sg[1] = NULL;
                 * you can force channel re-enable on the next tx_submit(), but
                 * this is dirty - think about descriptors with multiple
                 * sg elements.
                 */
                dev_warn(dev, "NFB4EOF on channel %d, ready %x, %x, cur %x\n",
                         chan_id, ready0, ready1, curbuf);
                return IRQ_HANDLED;
        }
        spin_unlock_irqrestore(&ipu_data.lock, flags);

        /* Other interrupts do not interfere with this channel */
        spin_lock(&ichan->lock);
        if (unlikely((ichan->active_buffer && (ready1 >> chan_id) & 1) ||
                     (!ichan->active_buffer && (ready0 >> chan_id) & 1)
                     )) {
                spin_unlock(&ichan->lock);
                dev_dbg(dev,
                        "IRQ with active buffer still ready on channel %x, "
                        "active %d, ready %x, %x!\n", chan_id,
                        ichan->active_buffer, ready0, ready1);
                return IRQ_NONE;
        }

        if (unlikely(list_empty(&ichan->queue))) {
                ichan->sg[ichan->active_buffer] = NULL;
                spin_unlock(&ichan->lock);
                dev_err(dev,
                        "IRQ without queued buffers on channel %x, active %d, "
                        "ready %x, %x!\n", chan_id,
                        ichan->active_buffer, ready0, ready1);
                return IRQ_NONE;
        }

        /*
         * active_buffer is a software flag, it shows which buffer we are
         * currently expecting back from the hardware, IDMAC should be
         * processing the other buffer already
         */
        sg = &ichan->sg[ichan->active_buffer];
        sgnext = ichan->sg[!ichan->active_buffer];

        if (!*sg) {
                spin_unlock(&ichan->lock);
                return IRQ_HANDLED;
        }

        desc = list_entry(ichan->queue.next, struct idmac_tx_desc, list);
        descnew = desc;

        dev_dbg(dev, "IDMAC irq %d, dma 0x%08x, next dma 0x%08x, current %d, curbuf 0x%08x\n",
                irq, sg_dma_address(*sg), sgnext ? sg_dma_address(sgnext) : 0, ichan->active_buffer, curbuf);

        /* Find the descriptor of sgnext */
        sgnew = idmac_sg_next(ichan, &descnew, *sg);
        if (sgnext != sgnew)
                dev_err(dev, "Submitted buffer %p, next buffer %p\n", sgnext, sgnew);

        /*
         * if sgnext == NULL sg must be the last element in a scatterlist and
         * queue must be empty
         */
        if (unlikely(!sgnext)) {
                if (!WARN_ON(sg_next(*sg)))
                        dev_dbg(dev, "Underrun on channel %x\n", chan_id);
                ichan->sg[!ichan->active_buffer] = sgnew;

                if (unlikely(sgnew)) {
                        ipu_submit_buffer(ichan, descnew, sgnew, !ichan->active_buffer);
                } else {
                        spin_lock_irqsave(&ipu_data.lock, flags);
                        ipu_ic_disable_task(&ipu_data, chan_id);
                        spin_unlock_irqrestore(&ipu_data.lock, flags);
                        ichan->status = IPU_CHANNEL_READY;
                        /* Continue to check for complete descriptor */
                }
        }

        /* Calculate and submit the next sg element */
        sgnew = idmac_sg_next(ichan, &descnew, sgnew);

        if (unlikely(!sg_next(*sg)) || !sgnext) {
                /*
                 * Last element in scatterlist done, remove from the queue,
                 * _init for debugging
                 */
                list_del_init(&desc->list);
                done = true;
        }

        *sg = sgnew;

        if (likely(sgnew) &&
            ipu_submit_buffer(ichan, descnew, sgnew, ichan->active_buffer) < 0) {
                callback = descnew->txd.callback;
                callback_param = descnew->txd.callback_param;
                list_del_init(&descnew->list);
                spin_unlock(&ichan->lock);
                if (callback)
                        callback(callback_param);
                spin_lock(&ichan->lock);
        }

        /* Flip the active buffer - even if update above failed */
        ichan->active_buffer = !ichan->active_buffer;
        if (done)
                dma_cookie_complete(&desc->txd);

        callback = desc->txd.callback;
        callback_param = desc->txd.callback_param;

        spin_unlock(&ichan->lock);

        if (done && (desc->txd.flags & DMA_PREP_INTERRUPT) && callback)
                callback(callback_param);

        return IRQ_HANDLED;
}

static void ipu_gc_tasklet(unsigned long arg)
{
        struct ipu *ipu = (struct ipu *)arg;
        int i;

        for (i = 0; i < IPU_CHANNELS_NUM; i++) {
                struct idmac_channel *ichan = ipu->channel + i;
                struct idmac_tx_desc *desc;
                unsigned long flags;
                struct scatterlist *sg;
                int j, k;

                for (j = 0; j < ichan->n_tx_desc; j++) {
                        desc = ichan->desc + j;
                        spin_lock_irqsave(&ichan->lock, flags);
                        if (async_tx_test_ack(&desc->txd)) {
                                list_move(&desc->list, &ichan->free_list);
                                for_each_sg(desc->sg, sg, desc->sg_len, k) {
                                        if (ichan->sg[0] == sg)
                                                ichan->sg[0] = NULL;
                                        else if (ichan->sg[1] == sg)
                                                ichan->sg[1] = NULL;
                                }
                                async_tx_clear_ack(&desc->txd);
                        }
                        spin_unlock_irqrestore(&ichan->lock, flags);
                }
        }
}

/* Allocate and initialise a transfer descriptor. */
static struct dma_async_tx_descriptor *idmac_prep_slave_sg(struct dma_chan *chan,
                struct scatterlist *sgl, unsigned int sg_len,
                enum dma_transfer_direction direction, unsigned long tx_flags,
                void *context)
{
        struct idmac_channel *ichan = to_idmac_chan(chan);
        struct idmac_tx_desc *desc = NULL;
        struct dma_async_tx_descriptor *txd = NULL;
        unsigned long flags;

        /* We only can handle these three channels so far */
        if (chan->chan_id != IDMAC_SDC_0 && chan->chan_id != IDMAC_SDC_1 &&
            chan->chan_id != IDMAC_IC_7)
                return NULL;

        if (direction != DMA_DEV_TO_MEM && direction != DMA_MEM_TO_DEV) {
                dev_err(chan->device->dev, "Invalid DMA direction %d!\n", direction);
                return NULL;
        }

        mutex_lock(&ichan->chan_mutex);

        spin_lock_irqsave(&ichan->lock, flags);
        if (!list_empty(&ichan->free_list)) {
                desc = list_entry(ichan->free_list.next,
                                  struct idmac_tx_desc, list);

                list_del_init(&desc->list);

                desc->sg_len    = sg_len;
                desc->sg        = sgl;
                txd             = &desc->txd;
                txd->flags      = tx_flags;
        }
        spin_unlock_irqrestore(&ichan->lock, flags);

        mutex_unlock(&ichan->chan_mutex);

        tasklet_schedule(&to_ipu(to_idmac(chan->device))->tasklet);

        return txd;
}

/* Re-select the current buffer and re-activate the channel */
static void idmac_issue_pending(struct dma_chan *chan)
{
        struct idmac_channel *ichan = to_idmac_chan(chan);
        struct idmac *idmac = to_idmac(chan->device);
        struct ipu *ipu = to_ipu(idmac);
        unsigned long flags;

        /* This is not always needed, but doesn't hurt either */
        spin_lock_irqsave(&ipu->lock, flags);
        ipu_select_buffer(chan->chan_id, ichan->active_buffer);
        spin_unlock_irqrestore(&ipu->lock, flags);

        /*
         * Might need to perform some parts of initialisation from
         * ipu_enable_channel(), but not all, we do not want to reset to buffer
         * 0, don't need to set priority again either, but re-enabling the task
         * and the channel might be a good idea.
         */
}

static int __idmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
                           unsigned long arg)
{
        struct idmac_channel *ichan = to_idmac_chan(chan);
        struct idmac *idmac = to_idmac(chan->device);
        struct ipu *ipu = to_ipu(idmac);
        struct list_head *list, *tmp;
        unsigned long flags;
        int i;

        switch (cmd) {
        case DMA_PAUSE:
                spin_lock_irqsave(&ipu->lock, flags);
                ipu_ic_disable_task(ipu, chan->chan_id);

                /* Return all descriptors into "prepared" state */
                list_for_each_safe(list, tmp, &ichan->queue)
                        list_del_init(list);

                ichan->sg[0] = NULL;
                ichan->sg[1] = NULL;

                spin_unlock_irqrestore(&ipu->lock, flags);

                ichan->status = IPU_CHANNEL_INITIALIZED;
                break;
        case DMA_TERMINATE_ALL:
                ipu_disable_channel(idmac, ichan,
                                    ichan->status >= IPU_CHANNEL_ENABLED);

                tasklet_disable(&ipu->tasklet);

                /* ichan->queue is modified in ISR, have to spinlock */
                spin_lock_irqsave(&ichan->lock, flags);
                list_splice_init(&ichan->queue, &ichan->free_list);

                if (ichan->desc)
                        for (i = 0; i < ichan->n_tx_desc; i++) {
                                struct idmac_tx_desc *desc = ichan->desc + i;
                                if (list_empty(&desc->list))
                                        /* Descriptor was prepared, but not submitted */
                                        list_add(&desc->list, &ichan->free_list);

                                async_tx_clear_ack(&desc->txd);
                        }

                ichan->sg[0] = NULL;
                ichan->sg[1] = NULL;
                spin_unlock_irqrestore(&ichan->lock, flags);

                tasklet_enable(&ipu->tasklet);

                ichan->status = IPU_CHANNEL_INITIALIZED;
                break;
        default:
                return -ENOSYS;
        }

        return 0;
}

static int idmac_control(struct dma_chan *chan, enum dma_ctrl_cmd cmd,
                         unsigned long arg)
{
        struct idmac_channel *ichan = to_idmac_chan(chan);
        int ret;

        mutex_lock(&ichan->chan_mutex);

        ret = __idmac_control(chan, cmd, arg);

        mutex_unlock(&ichan->chan_mutex);

        return ret;
}

#ifdef DEBUG
static irqreturn_t ic_sof_irq(int irq, void *dev_id)
{
        struct idmac_channel *ichan = dev_id;
        printk(KERN_DEBUG "Got SOF IRQ %d on Channel %d\n",
               irq, ichan->dma_chan.chan_id);
        disable_irq_nosync(irq);
        return IRQ_HANDLED;
}

static irqreturn_t ic_eof_irq(int irq, void *dev_id)
{
        struct idmac_channel *ichan = dev_id;
        printk(KERN_DEBUG "Got EOF IRQ %d on Channel %d\n",
               irq, ichan->dma_chan.chan_id);
        disable_irq_nosync(irq);
        return IRQ_HANDLED;
}

static int ic_sof = -EINVAL, ic_eof = -EINVAL;
#endif

static int idmac_alloc_chan_resources(struct dma_chan *chan)
{
        struct idmac_channel *ichan = to_idmac_chan(chan);
        struct idmac *idmac = to_idmac(chan->device);
        int ret;

        /* dmaengine.c now guarantees to only offer free channels */
        BUG_ON(chan->client_count > 1);
        WARN_ON(ichan->status != IPU_CHANNEL_FREE);

        dma_cookie_init(chan);

        ret = ipu_irq_map(chan->chan_id);
        if (ret < 0)
                goto eimap;

        ichan->eof_irq = ret;

        /*
         * Important to first disable the channel, because maybe someone
         * used it before us, e.g., the bootloader
         */
        ipu_disable_channel(idmac, ichan, true);

        ret = ipu_init_channel(idmac, ichan);
        if (ret < 0)
                goto eichan;

        ret = request_irq(ichan->eof_irq, idmac_interrupt, 0,
                          ichan->eof_name, ichan);
        if (ret < 0)
                goto erirq;

#ifdef DEBUG
        if (chan->chan_id == IDMAC_IC_7) {
                ic_sof = ipu_irq_map(69);
                if (ic_sof > 0)
                        request_irq(ic_sof, ic_sof_irq, 0, "IC SOF", ichan);
                ic_eof = ipu_irq_map(70);
                if (ic_eof > 0)
                        request_irq(ic_eof, ic_eof_irq, 0, "IC EOF", ichan);
        }
#endif

        ichan->status = IPU_CHANNEL_INITIALIZED;

        dev_dbg(&chan->dev->device, "Found channel 0x%x, irq %d\n",
                chan->chan_id, ichan->eof_irq);

        return ret;

erirq:
        ipu_uninit_channel(idmac, ichan);
eichan:
        ipu_irq_unmap(chan->chan_id);
eimap:
        return ret;
}

static void idmac_free_chan_resources(struct dma_chan *chan)
{
        struct idmac_channel *ichan = to_idmac_chan(chan);
        struct idmac *idmac = to_idmac(chan->device);

        mutex_lock(&ichan->chan_mutex);

        __idmac_control(chan, DMA_TERMINATE_ALL, 0);

        if (ichan->status > IPU_CHANNEL_FREE) {
#ifdef DEBUG
                if (chan->chan_id == IDMAC_IC_7) {
                        if (ic_sof > 0) {
                                free_irq(ic_sof, ichan);
                                ipu_irq_unmap(69);
                                ic_sof = -EINVAL;
                        }
                        if (ic_eof > 0) {
                                free_irq(ic_eof, ichan);
                                ipu_irq_unmap(70);
                                ic_eof = -EINVAL;
                        }
                }
#endif
                free_irq(ichan->eof_irq, ichan);
                ipu_irq_unmap(chan->chan_id);
        }

        ichan->status = IPU_CHANNEL_FREE;

        ipu_uninit_channel(idmac, ichan);

        mutex_unlock(&ichan->chan_mutex);

        tasklet_schedule(&to_ipu(idmac)->tasklet);
}

static enum dma_status idmac_tx_status(struct dma_chan *chan,
                       dma_cookie_t cookie, struct dma_tx_state *txstate)
{
        dma_set_tx_state(txstate, chan->completed_cookie, chan->cookie, 0);
        if (cookie != chan->cookie)
                return DMA_ERROR;
        return DMA_SUCCESS;
}

static int __init ipu_idmac_init(struct ipu *ipu)
{
        struct idmac *idmac = &ipu->idmac;
        struct dma_device *dma = &idmac->dma;
        int i;

        dma_cap_set(DMA_SLAVE, dma->cap_mask);
        dma_cap_set(DMA_PRIVATE, dma->cap_mask);

        /* Compulsory common fields */
        dma->dev                                = ipu->dev;
        dma->device_alloc_chan_resources        = idmac_alloc_chan_resources;
        dma->device_free_chan_resources         = idmac_free_chan_resources;
        dma->device_tx_status                   = idmac_tx_status;
        dma->device_issue_pending               = idmac_issue_pending;

        /* Compulsory for DMA_SLAVE fields */
        dma->device_prep_slave_sg               = idmac_prep_slave_sg;
        dma->device_control                     = idmac_control;

        INIT_LIST_HEAD(&dma->channels);
        for (i = 0; i < IPU_CHANNELS_NUM; i++) {
                struct idmac_channel *ichan = ipu->channel + i;
                struct dma_chan *dma_chan = &ichan->dma_chan;

                spin_lock_init(&ichan->lock);
                mutex_init(&ichan->chan_mutex);

                ichan->status           = IPU_CHANNEL_FREE;
                ichan->sec_chan_en      = false;
                snprintf(ichan->eof_name, sizeof(ichan->eof_name), "IDMAC EOF %d", i);

                dma_chan->device        = &idmac->dma;
                dma_cookie_init(dma_chan);
                dma_chan->chan_id       = i;
                list_add_tail(&dma_chan->device_node, &dma->channels);
        }

        idmac_write_icreg(ipu, 0x00000070, IDMAC_CONF);

        return dma_async_device_register(&idmac->dma);
}

static void __exit ipu_idmac_exit(struct ipu *ipu)
{
        int i;
        struct idmac *idmac = &ipu->idmac;

        for (i = 0; i < IPU_CHANNELS_NUM; i++) {
                struct idmac_channel *ichan = ipu->channel + i;

                idmac_control(&ichan->dma_chan, DMA_TERMINATE_ALL, 0);
        }

        dma_async_device_unregister(&idmac->dma);
}

/*****************************************************************************
 * IPU common probe / remove
 */

static int __init ipu_probe(struct platform_device *pdev)
{
        struct resource *mem_ipu, *mem_ic;
        int ret;

        spin_lock_init(&ipu_data.lock);

        mem_ipu = platform_get_resource(pdev, IORESOURCE_MEM, 0);
        mem_ic  = platform_get_resource(pdev, IORESOURCE_MEM, 1);
        if (!mem_ipu || !mem_ic)
                return -EINVAL;

        ipu_data.dev = &pdev->dev;

        platform_set_drvdata(pdev, &ipu_data);

        ret = platform_get_irq(pdev, 0);
        if (ret < 0)
                goto err_noirq;

        ipu_data.irq_fn = ret;
        ret = platform_get_irq(pdev, 1);
        if (ret < 0)
                goto err_noirq;

        ipu_data.irq_err = ret;

        dev_dbg(&pdev->dev, "fn irq %u, err irq %u\n",
                ipu_data.irq_fn, ipu_data.irq_err);

        /* Remap IPU common registers */
        ipu_data.reg_ipu = ioremap(mem_ipu->start, resource_size(mem_ipu));
        if (!ipu_data.reg_ipu) {
                ret = -ENOMEM;
                goto err_ioremap_ipu;
        }

        /* Remap Image Converter and Image DMA Controller registers */
        ipu_data.reg_ic = ioremap(mem_ic->start, resource_size(mem_ic));
        if (!ipu_data.reg_ic) {
                ret = -ENOMEM;
                goto err_ioremap_ic;
        }

        /* Get IPU clock */
        ipu_data.ipu_clk = clk_get(&pdev->dev, NULL);
        if (IS_ERR(ipu_data.ipu_clk)) {
                ret = PTR_ERR(ipu_data.ipu_clk);
                goto err_clk_get;
        }

        /* Make sure IPU HSP clock is running */
        clk_prepare_enable(ipu_data.ipu_clk);

        /* Disable all interrupts */
        idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_1);
        idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_2);
        idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_3);
        idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_4);
        idmac_write_ipureg(&ipu_data, 0, IPU_INT_CTRL_5);

        dev_dbg(&pdev->dev, "%s @ 0x%08lx, fn irq %u, err irq %u\n", pdev->name,
                (unsigned long)mem_ipu->start, ipu_data.irq_fn, ipu_data.irq_err);

        ret = ipu_irq_attach_irq(&ipu_data, pdev);
        if (ret < 0)
                goto err_attach_irq;

        /* Initialize DMA engine */
        ret = ipu_idmac_init(&ipu_data);
        if (ret < 0)
                goto err_idmac_init;

        tasklet_init(&ipu_data.tasklet, ipu_gc_tasklet, (unsigned long)&ipu_data);

        ipu_data.dev = &pdev->dev;

        dev_dbg(ipu_data.dev, "IPU initialized\n");

        return 0;

err_idmac_init:
err_attach_irq:
        ipu_irq_detach_irq(&ipu_data, pdev);
        clk_disable_unprepare(ipu_data.ipu_clk);
        clk_put(ipu_data.ipu_clk);
err_clk_get:
        iounmap(ipu_data.reg_ic);
err_ioremap_ic:
        iounmap(ipu_data.reg_ipu);
err_ioremap_ipu:
err_noirq:
        dev_err(&pdev->dev, "Failed to probe IPU: %d\n", ret);
        return ret;
}

static int __exit ipu_remove(struct platform_device *pdev)
{
        struct ipu *ipu = platform_get_drvdata(pdev);

        ipu_idmac_exit(ipu);
        ipu_irq_detach_irq(ipu, pdev);
        clk_disable_unprepare(ipu->ipu_clk);
        clk_put(ipu->ipu_clk);
        iounmap(ipu->reg_ic);
        iounmap(ipu->reg_ipu);
        tasklet_kill(&ipu->tasklet);
        platform_set_drvdata(pdev, NULL);

        return 0;
}

/*
 * We need two MEM resources - with IPU-common and Image Converter registers,
 * including PF_CONF and IDMAC_* registers, and two IRQs - function and error
 */
static struct platform_driver ipu_platform_driver = {
        .driver = {
                .name   = "ipu-core",
                .owner  = THIS_MODULE,
        },
        .remove         = __exit_p(ipu_remove),
};

static int __init ipu_init(void)
{
        return platform_driver_probe(&ipu_platform_driver, ipu_probe);
}
subsys_initcall(ipu_init);

MODULE_DESCRIPTION("IPU core driver");
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
MODULE_ALIAS("platform:ipu-core");