// SPDX-License-Identifier: GPL-2.0+
/*
 * TI OMAP4 ISS V4L2 Driver
 *
 * Copyright (C) 2012, Texas Instruments
 *
 * Author: Sergio Aguirre <sergio.a.aguirre@gmail.com>
 */

#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/dma-mapping.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/mfd/syscon.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/sched.h>
#include <linux/vmalloc.h>

#include <media/v4l2-common.h>
#include <media/v4l2-device.h>
#include <media/v4l2-ctrls.h>

#include "iss.h"
#include "iss_regs.h"

#define ISS_PRINT_REGISTER(iss, name)\
        dev_dbg(iss->dev, "###ISS " #name "=0x%08x\n", \
                iss_reg_read(iss, OMAP4_ISS_MEM_TOP, ISS_##name))

static void iss_print_status(struct iss_device *iss)
{
        dev_dbg(iss->dev, "-------------ISS HL Register dump-------------\n");

        ISS_PRINT_REGISTER(iss, HL_REVISION);
        ISS_PRINT_REGISTER(iss, HL_SYSCONFIG);
        ISS_PRINT_REGISTER(iss, HL_IRQSTATUS(5));
        ISS_PRINT_REGISTER(iss, HL_IRQENABLE_SET(5));
        ISS_PRINT_REGISTER(iss, HL_IRQENABLE_CLR(5));
        ISS_PRINT_REGISTER(iss, CTRL);
        ISS_PRINT_REGISTER(iss, CLKCTRL);
        ISS_PRINT_REGISTER(iss, CLKSTAT);

        dev_dbg(iss->dev, "-----------------------------------------------\n");
}

/*
 * omap4iss_flush - Post pending L3 bus writes by doing a register readback
 * @iss: OMAP4 ISS device
 *
 * In order to force posting of pending writes, we need to write and
 * readback the same register, in this case the revision register.
 *
 * See this link for reference:
 *   https://www.mail-archive.com/linux-omap@vger.kernel.org/msg08149.html
 */
static void omap4iss_flush(struct iss_device *iss)
{
        iss_reg_write(iss, OMAP4_ISS_MEM_TOP, ISS_HL_REVISION, 0);
        iss_reg_read(iss, OMAP4_ISS_MEM_TOP, ISS_HL_REVISION);
}

/*
 * iss_isp_enable_interrupts - Enable ISS ISP interrupts.
 * @iss: OMAP4 ISS device
 */
static void omap4iss_isp_enable_interrupts(struct iss_device *iss)
{
        static const u32 isp_irq = ISP5_IRQ_OCP_ERR |
                                   ISP5_IRQ_RSZ_FIFO_IN_BLK_ERR |
                                   ISP5_IRQ_RSZ_FIFO_OVF |
                                   ISP5_IRQ_RSZ_INT_DMA |
                                   ISP5_IRQ_ISIF_INT(0);

        /* Enable ISP interrupts */
        iss_reg_write(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_IRQSTATUS(0), isp_irq);
        iss_reg_write(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_IRQENABLE_SET(0),
                      isp_irq);
}

/*
 * iss_isp_disable_interrupts - Disable ISS interrupts.
 * @iss: OMAP4 ISS device
 */
static void omap4iss_isp_disable_interrupts(struct iss_device *iss)
{
        iss_reg_write(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_IRQENABLE_CLR(0), ~0);
}

/*
 * iss_enable_interrupts - Enable ISS interrupts.
 * @iss: OMAP4 ISS device
 */
static void iss_enable_interrupts(struct iss_device *iss)
{
        static const u32 hl_irq = ISS_HL_IRQ_CSIA | ISS_HL_IRQ_CSIB
                                | ISS_HL_IRQ_ISP(0);

        /* Enable HL interrupts */
        iss_reg_write(iss, OMAP4_ISS_MEM_TOP, ISS_HL_IRQSTATUS(5), hl_irq);
        iss_reg_write(iss, OMAP4_ISS_MEM_TOP, ISS_HL_IRQENABLE_SET(5), hl_irq);

        if (iss->regs[OMAP4_ISS_MEM_ISP_SYS1])
                omap4iss_isp_enable_interrupts(iss);
}

/*
 * iss_disable_interrupts - Disable ISS interrupts.
 * @iss: OMAP4 ISS device
 */
static void iss_disable_interrupts(struct iss_device *iss)
{
        if (iss->regs[OMAP4_ISS_MEM_ISP_SYS1])
                omap4iss_isp_disable_interrupts(iss);

        iss_reg_write(iss, OMAP4_ISS_MEM_TOP, ISS_HL_IRQENABLE_CLR(5), ~0);
}

int omap4iss_get_external_info(struct iss_pipeline *pipe,
                               struct media_link *link)
{
        struct iss_device *iss =
                container_of(pipe, struct iss_video, pipe)->iss;
        struct v4l2_subdev_format fmt;
        struct v4l2_ctrl *ctrl;
        int ret;

        if (!pipe->external)
                return 0;

        if (pipe->external_rate)
                return 0;

        memset(&fmt, 0, sizeof(fmt));

        fmt.pad = link->source->index;
        fmt.which = V4L2_SUBDEV_FORMAT_ACTIVE;
        ret = v4l2_subdev_call(media_entity_to_v4l2_subdev(link->sink->entity),
                               pad, get_fmt, NULL, &fmt);
        if (ret < 0)
                return -EPIPE;

        pipe->external_bpp = omap4iss_video_format_info(fmt.format.code)->bpp;

        ctrl = v4l2_ctrl_find(pipe->external->ctrl_handler,
                              V4L2_CID_PIXEL_RATE);
        if (!ctrl) {
                dev_warn(iss->dev, "no pixel rate control in subdev %s\n",
                         pipe->external->name);
                return -EPIPE;
        }

        pipe->external_rate = v4l2_ctrl_g_ctrl_int64(ctrl);

        return 0;
}

/*
 * Configure the bridge. Valid inputs are
 *
 * IPIPEIF_INPUT_CSI2A: CSI2a receiver
 * IPIPEIF_INPUT_CSI2B: CSI2b receiver
 *
 * The bridge and lane shifter are configured according to the selected input
 * and the ISP platform data.
 */
void omap4iss_configure_bridge(struct iss_device *iss,
                               enum ipipeif_input_entity input)
{
        u32 issctrl_val;
        u32 isp5ctrl_val;

        issctrl_val = iss_reg_read(iss, OMAP4_ISS_MEM_TOP, ISS_CTRL);
        issctrl_val &= ~ISS_CTRL_INPUT_SEL_MASK;
        issctrl_val &= ~ISS_CTRL_CLK_DIV_MASK;

        isp5ctrl_val = iss_reg_read(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_CTRL);

        switch (input) {
        case IPIPEIF_INPUT_CSI2A:
                issctrl_val |= ISS_CTRL_INPUT_SEL_CSI2A;
                break;

        case IPIPEIF_INPUT_CSI2B:
                issctrl_val |= ISS_CTRL_INPUT_SEL_CSI2B;
                break;

        default:
                return;
        }

        issctrl_val |= ISS_CTRL_SYNC_DETECT_VS_RAISING;

        isp5ctrl_val |= ISP5_CTRL_VD_PULSE_EXT | ISP5_CTRL_PSYNC_CLK_SEL |
                        ISP5_CTRL_SYNC_ENABLE;

        iss_reg_write(iss, OMAP4_ISS_MEM_TOP, ISS_CTRL, issctrl_val);
        iss_reg_write(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_CTRL, isp5ctrl_val);
}

#ifdef ISS_ISR_DEBUG
static void iss_isr_dbg(struct iss_device *iss, u32 irqstatus)
{
        static const char * const name[] = {
                "ISP_0",
                "ISP_1",
                "ISP_2",
                "ISP_3",
                "CSIA",
                "CSIB",
                "CCP2_0",
                "CCP2_1",
                "CCP2_2",
                "CCP2_3",
                "CBUFF",
                "BTE",
                "SIMCOP_0",
                "SIMCOP_1",
                "SIMCOP_2",
                "SIMCOP_3",
                "CCP2_8",
                "HS_VS",
                "18",
                "19",
                "20",
                "21",
                "22",
                "23",
                "24",
                "25",
                "26",
                "27",
                "28",
                "29",
                "30",
                "31",
        };
        unsigned int i;

        dev_dbg(iss->dev, "ISS IRQ: ");

        for (i = 0; i < ARRAY_SIZE(name); i++) {
                if ((1 << i) & irqstatus)
                        pr_cont("%s ", name[i]);
        }
        pr_cont("\n");
}

static void iss_isp_isr_dbg(struct iss_device *iss, u32 irqstatus)
{
        static const char * const name[] = {
                "ISIF_0",
                "ISIF_1",
                "ISIF_2",
                "ISIF_3",
                "IPIPEREQ",
                "IPIPELAST_PIX",
                "IPIPEDMA",
                "IPIPEBSC",
                "IPIPEHST",
                "IPIPEIF",
                "AEW",
                "AF",
                "H3A",
                "RSZ_REG",
                "RSZ_LAST_PIX",
                "RSZ_DMA",
                "RSZ_CYC_RZA",
                "RSZ_CYC_RZB",
                "RSZ_FIFO_OVF",
                "RSZ_FIFO_IN_BLK_ERR",
                "20",
                "21",
                "RSZ_EOF0",
                "RSZ_EOF1",
                "H3A_EOF",
                "IPIPE_EOF",
                "26",
                "IPIPE_DPC_INI",
                "IPIPE_DPC_RNEW0",
                "IPIPE_DPC_RNEW1",
                "30",
                "OCP_ERR",
        };
        unsigned int i;

        dev_dbg(iss->dev, "ISP IRQ: ");

        for (i = 0; i < ARRAY_SIZE(name); i++) {
                if ((1 << i) & irqstatus)
                        pr_cont("%s ", name[i]);
        }
        pr_cont("\n");
}
#endif

/*
 * iss_isr - Interrupt Service Routine for ISS module.
 * @irq: Not used currently.
 * @_iss: Pointer to the OMAP4 ISS device
 *
 * Handles the corresponding callback if plugged in.
 *
 * Returns IRQ_HANDLED when IRQ was correctly handled, or IRQ_NONE when the
 * IRQ wasn't handled.
 */
static irqreturn_t iss_isr(int irq, void *_iss)
{
        static const u32 ipipeif_events = ISP5_IRQ_IPIPEIF_IRQ |
                                          ISP5_IRQ_ISIF_INT(0);
        static const u32 resizer_events = ISP5_IRQ_RSZ_FIFO_IN_BLK_ERR |
                                          ISP5_IRQ_RSZ_FIFO_OVF |
                                          ISP5_IRQ_RSZ_INT_DMA;
        struct iss_device *iss = _iss;
        u32 irqstatus;

        irqstatus = iss_reg_read(iss, OMAP4_ISS_MEM_TOP, ISS_HL_IRQSTATUS(5));
        iss_reg_write(iss, OMAP4_ISS_MEM_TOP, ISS_HL_IRQSTATUS(5), irqstatus);

        if (irqstatus & ISS_HL_IRQ_CSIA)
                omap4iss_csi2_isr(&iss->csi2a);

        if (irqstatus & ISS_HL_IRQ_CSIB)
                omap4iss_csi2_isr(&iss->csi2b);

        if (irqstatus & ISS_HL_IRQ_ISP(0)) {
                u32 isp_irqstatus = iss_reg_read(iss, OMAP4_ISS_MEM_ISP_SYS1,
                                                 ISP5_IRQSTATUS(0));
                iss_reg_write(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_IRQSTATUS(0),
                              isp_irqstatus);

                if (isp_irqstatus & ISP5_IRQ_OCP_ERR)
                        dev_dbg(iss->dev, "ISP5 OCP Error!\n");

                if (isp_irqstatus & ipipeif_events) {
                        omap4iss_ipipeif_isr(&iss->ipipeif,
                                             isp_irqstatus & ipipeif_events);
                }

                if (isp_irqstatus & resizer_events)
                        omap4iss_resizer_isr(&iss->resizer,
                                             isp_irqstatus & resizer_events);

#ifdef ISS_ISR_DEBUG
                iss_isp_isr_dbg(iss, isp_irqstatus);
#endif
        }

        omap4iss_flush(iss);

#ifdef ISS_ISR_DEBUG
        iss_isr_dbg(iss, irqstatus);
#endif

        return IRQ_HANDLED;
}

static const struct media_device_ops iss_media_ops = {
        .link_notify = v4l2_pipeline_link_notify,
};

/* -----------------------------------------------------------------------------
 * Pipeline stream management
 */

/*
 * iss_pipeline_disable - Disable streaming on a pipeline
 * @pipe: ISS pipeline
 * @until: entity at which to stop pipeline walk
 *
 * Walk the entities chain starting at the pipeline output video node and stop
 * all modules in the chain. Wait synchronously for the modules to be stopped if
 * necessary.
 *
 * If the until argument isn't NULL, stop the pipeline walk when reaching the
 * until entity. This is used to disable a partially started pipeline due to a
 * subdev start error.
 */
static int iss_pipeline_disable(struct iss_pipeline *pipe,
                                struct media_entity *until)
{
        struct iss_device *iss = pipe->output->iss;
        struct media_entity *entity;
        struct media_pad *pad;
        struct v4l2_subdev *subdev;
        int failure = 0;
        int ret;

        entity = &pipe->output->video.entity;
        while (1) {
                pad = &entity->pads[0];
                if (!(pad->flags & MEDIA_PAD_FL_SINK))
                        break;

                pad = media_entity_remote_pad(pad);
                if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
                        break;

                entity = pad->entity;
                if (entity == until)
                        break;

                subdev = media_entity_to_v4l2_subdev(entity);
                ret = v4l2_subdev_call(subdev, video, s_stream, 0);
                if (ret < 0) {
                        dev_warn(iss->dev, "%s: module stop timeout.\n",
                                 subdev->name);
                        /* If the entity failed to stopped, assume it has
                         * crashed. Mark it as such, the ISS will be reset when
                         * applications will release it.
                         */
                        media_entity_enum_set(&iss->crashed, &subdev->entity);
                        failure = -ETIMEDOUT;
                }
        }

        return failure;
}

/*
 * iss_pipeline_enable - Enable streaming on a pipeline
 * @pipe: ISS pipeline
 * @mode: Stream mode (single shot or continuous)
 *
 * Walk the entities chain starting at the pipeline output video node and start
 * all modules in the chain in the given mode.
 *
 * Return 0 if successful, or the return value of the failed video::s_stream
 * operation otherwise.
 */
static int iss_pipeline_enable(struct iss_pipeline *pipe,
                               enum iss_pipeline_stream_state mode)
{
        struct iss_device *iss = pipe->output->iss;
        struct media_entity *entity;
        struct media_pad *pad;
        struct v4l2_subdev *subdev;
        unsigned long flags;
        int ret;

        /* If one of the entities in the pipeline has crashed it will not work
         * properly. Refuse to start streaming in that case. This check must be
         * performed before the loop below to avoid starting entities if the
         * pipeline won't start anyway (those entities would then likely fail to
         * stop, making the problem worse).
         */
        if (media_entity_enum_intersects(&pipe->ent_enum, &iss->crashed))
                return -EIO;

        spin_lock_irqsave(&pipe->lock, flags);
        pipe->state &= ~(ISS_PIPELINE_IDLE_INPUT | ISS_PIPELINE_IDLE_OUTPUT);
        spin_unlock_irqrestore(&pipe->lock, flags);

        pipe->do_propagation = false;

        mutex_lock(&iss->media_dev.graph_mutex);

        entity = &pipe->output->video.entity;
        while (1) {
                pad = &entity->pads[0];
                if (!(pad->flags & MEDIA_PAD_FL_SINK))
                        break;

                pad = media_entity_remote_pad(pad);
                if (!pad || !is_media_entity_v4l2_subdev(pad->entity))
                        break;

                entity = pad->entity;
                subdev = media_entity_to_v4l2_subdev(entity);

                ret = v4l2_subdev_call(subdev, video, s_stream, mode);
                if (ret < 0 && ret != -ENOIOCTLCMD) {
                        iss_pipeline_disable(pipe, entity);
                        mutex_unlock(&iss->media_dev.graph_mutex);
                        return ret;
                }

                if (subdev == &iss->csi2a.subdev ||
                    subdev == &iss->csi2b.subdev)
                        pipe->do_propagation = true;
        }

        mutex_unlock(&iss->media_dev.graph_mutex);
        iss_print_status(pipe->output->iss);

        return 0;
}

/*
 * omap4iss_pipeline_set_stream - Enable/disable streaming on a pipeline
 * @pipe: ISS pipeline
 * @state: Stream state (stopped, single shot or continuous)
 *
 * Set the pipeline to the given stream state. Pipelines can be started in
 * single-shot or continuous mode.
 *
 * Return 0 if successful, or the return value of the failed video::s_stream
 * operation otherwise. The pipeline state is not updated when the operation
 * fails, except when stopping the pipeline.
 */
int omap4iss_pipeline_set_stream(struct iss_pipeline *pipe,
                                 enum iss_pipeline_stream_state state)
{
        int ret;

        if (state == ISS_PIPELINE_STREAM_STOPPED)
                ret = iss_pipeline_disable(pipe, NULL);
        else
                ret = iss_pipeline_enable(pipe, state);

        if (ret == 0 || state == ISS_PIPELINE_STREAM_STOPPED)
                pipe->stream_state = state;

        return ret;
}

/*
 * omap4iss_pipeline_cancel_stream - Cancel stream on a pipeline
 * @pipe: ISS pipeline
 *
 * Cancelling a stream mark all buffers on all video nodes in the pipeline as
 * erroneous and makes sure no new buffer can be queued. This function is called
 * when a fatal error that prevents any further operation on the pipeline
 * occurs.
 */
void omap4iss_pipeline_cancel_stream(struct iss_pipeline *pipe)
{
        if (pipe->input)
                omap4iss_video_cancel_stream(pipe->input);
        if (pipe->output)
                omap4iss_video_cancel_stream(pipe->output);
}

/*
 * iss_pipeline_is_last - Verify if entity has an enabled link to the output
 *                        video node
 * @me: ISS module's media entity
 *
 * Returns 1 if the entity has an enabled link to the output video node or 0
 * otherwise. It's true only while pipeline can have no more than one output
 * node.
 */
static int iss_pipeline_is_last(struct media_entity *me)
{
        struct iss_pipeline *pipe;
        struct media_pad *pad;

        if (!me->pipe)
                return 0;
        pipe = to_iss_pipeline(me);
        if (pipe->stream_state == ISS_PIPELINE_STREAM_STOPPED)
                return 0;
        pad = media_entity_remote_pad(&pipe->output->pad);
        return pad->entity == me;
}

static int iss_reset(struct iss_device *iss)
{
        unsigned int timeout;

        iss_reg_set(iss, OMAP4_ISS_MEM_TOP, ISS_HL_SYSCONFIG,
                    ISS_HL_SYSCONFIG_SOFTRESET);

        timeout = iss_poll_condition_timeout(
                !(iss_reg_read(iss, OMAP4_ISS_MEM_TOP, ISS_HL_SYSCONFIG) &
                ISS_HL_SYSCONFIG_SOFTRESET), 1000, 10, 100);
        if (timeout) {
                dev_err(iss->dev, "ISS reset timeout\n");
                return -ETIMEDOUT;
        }

        media_entity_enum_zero(&iss->crashed);

        return 0;
}

static int iss_isp_reset(struct iss_device *iss)
{
        unsigned int timeout;

        /* Fist, ensure that the ISP is IDLE (no transactions happening) */
        iss_reg_update(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_SYSCONFIG,
                       ISP5_SYSCONFIG_STANDBYMODE_MASK,
                       ISP5_SYSCONFIG_STANDBYMODE_SMART);

        iss_reg_set(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_CTRL, ISP5_CTRL_MSTANDBY);

        timeout = iss_poll_condition_timeout(
                iss_reg_read(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_CTRL) &
                ISP5_CTRL_MSTANDBY_WAIT, 1000000, 1000, 1500);
        if (timeout) {
                dev_err(iss->dev, "ISP5 standby timeout\n");
                return -ETIMEDOUT;
        }

        /* Now finally, do the reset */
        iss_reg_set(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_SYSCONFIG,
                    ISP5_SYSCONFIG_SOFTRESET);

        timeout = iss_poll_condition_timeout(
                !(iss_reg_read(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_SYSCONFIG) &
                ISP5_SYSCONFIG_SOFTRESET), 1000000, 1000, 1500);
        if (timeout) {
                dev_err(iss->dev, "ISP5 reset timeout\n");
                return -ETIMEDOUT;
        }

        return 0;
}

/*
 * iss_module_sync_idle - Helper to sync module with its idle state
 * @me: ISS submodule's media entity
 * @wait: ISS submodule's wait queue for streamoff/interrupt synchronization
 * @stopping: flag which tells module wants to stop
 *
 * This function checks if ISS submodule needs to wait for next interrupt. If
 * yes, makes the caller to sleep while waiting for such event.
 */
int omap4iss_module_sync_idle(struct media_entity *me, wait_queue_head_t *wait,
                              atomic_t *stopping)
{
        struct iss_pipeline *pipe = to_iss_pipeline(me);
        struct iss_video *video = pipe->output;
        unsigned long flags;

        if (pipe->stream_state == ISS_PIPELINE_STREAM_STOPPED ||
            (pipe->stream_state == ISS_PIPELINE_STREAM_SINGLESHOT &&
             !iss_pipeline_ready(pipe)))
                return 0;

        /*
         * atomic_set() doesn't include memory barrier on ARM platform for SMP
         * scenario. We'll call it here to avoid race conditions.
         */
        atomic_set(stopping, 1);
        smp_wmb();

        /*
         * If module is the last one, it's writing to memory. In this case,
         * it's necessary to check if the module is already paused due to
         * DMA queue underrun or if it has to wait for next interrupt to be
         * idle.
         * If it isn't the last one, the function won't sleep but *stopping
         * will still be set to warn next submodule caller's interrupt the
         * module wants to be idle.
         */
        if (!iss_pipeline_is_last(me))
                return 0;

        spin_lock_irqsave(&video->qlock, flags);
        if (video->dmaqueue_flags & ISS_VIDEO_DMAQUEUE_UNDERRUN) {
                spin_unlock_irqrestore(&video->qlock, flags);
                atomic_set(stopping, 0);
                smp_wmb();
                return 0;
        }
        spin_unlock_irqrestore(&video->qlock, flags);
        if (!wait_event_timeout(*wait, !atomic_read(stopping),
                                msecs_to_jiffies(1000))) {
                atomic_set(stopping, 0);
                smp_wmb();
                return -ETIMEDOUT;
        }

        return 0;
}

/*
 * omap4iss_module_sync_is_stopped - Helper to verify if module was stopping
 * @wait: ISS submodule's wait queue for streamoff/interrupt synchronization
 * @stopping: flag which tells module wants to stop
 *
 * This function checks if ISS submodule was stopping. In case of yes, it
 * notices the caller by setting stopping to 0 and waking up the wait queue.
 * Returns 1 if it was stopping or 0 otherwise.
 */
int omap4iss_module_sync_is_stopping(wait_queue_head_t *wait,
                                     atomic_t *stopping)
{
        if (atomic_cmpxchg(stopping, 1, 0)) {
                wake_up(wait);
                return 1;
        }

        return 0;
}

/* --------------------------------------------------------------------------
 * Clock management
 */

#define ISS_CLKCTRL_MASK        (ISS_CLKCTRL_CSI2_A |\
                                 ISS_CLKCTRL_CSI2_B |\
                                 ISS_CLKCTRL_ISP)

static int __iss_subclk_update(struct iss_device *iss)
{
        u32 clk = 0;
        int ret = 0, timeout = 1000;

        if (iss->subclk_resources & OMAP4_ISS_SUBCLK_CSI2_A)
                clk |= ISS_CLKCTRL_CSI2_A;

        if (iss->subclk_resources & OMAP4_ISS_SUBCLK_CSI2_B)
                clk |= ISS_CLKCTRL_CSI2_B;

        if (iss->subclk_resources & OMAP4_ISS_SUBCLK_ISP)
                clk |= ISS_CLKCTRL_ISP;

        iss_reg_update(iss, OMAP4_ISS_MEM_TOP, ISS_CLKCTRL,
                       ISS_CLKCTRL_MASK, clk);

        /* Wait for HW assertion */
        while (--timeout > 0) {
                udelay(1);
                if ((iss_reg_read(iss, OMAP4_ISS_MEM_TOP, ISS_CLKSTAT) &
                    ISS_CLKCTRL_MASK) == clk)
                        break;
        }

        if (!timeout)
                ret = -EBUSY;

        return ret;
}

int omap4iss_subclk_enable(struct iss_device *iss,
                           enum iss_subclk_resource res)
{
        iss->subclk_resources |= res;

        return __iss_subclk_update(iss);
}

int omap4iss_subclk_disable(struct iss_device *iss,
                            enum iss_subclk_resource res)
{
        iss->subclk_resources &= ~res;

        return __iss_subclk_update(iss);
}

#define ISS_ISP5_CLKCTRL_MASK   (ISP5_CTRL_BL_CLK_ENABLE |\
                                 ISP5_CTRL_ISIF_CLK_ENABLE |\
                                 ISP5_CTRL_H3A_CLK_ENABLE |\
                                 ISP5_CTRL_RSZ_CLK_ENABLE |\
                                 ISP5_CTRL_IPIPE_CLK_ENABLE |\
                                 ISP5_CTRL_IPIPEIF_CLK_ENABLE)

static void __iss_isp_subclk_update(struct iss_device *iss)
{
        u32 clk = 0;

        if (iss->isp_subclk_resources & OMAP4_ISS_ISP_SUBCLK_ISIF)
                clk |= ISP5_CTRL_ISIF_CLK_ENABLE;

        if (iss->isp_subclk_resources & OMAP4_ISS_ISP_SUBCLK_H3A)
                clk |= ISP5_CTRL_H3A_CLK_ENABLE;

        if (iss->isp_subclk_resources & OMAP4_ISS_ISP_SUBCLK_RSZ)
                clk |= ISP5_CTRL_RSZ_CLK_ENABLE;

        if (iss->isp_subclk_resources & OMAP4_ISS_ISP_SUBCLK_IPIPE)
                clk |= ISP5_CTRL_IPIPE_CLK_ENABLE;

        if (iss->isp_subclk_resources & OMAP4_ISS_ISP_SUBCLK_IPIPEIF)
                clk |= ISP5_CTRL_IPIPEIF_CLK_ENABLE;

        if (clk)
                clk |= ISP5_CTRL_BL_CLK_ENABLE;

        iss_reg_update(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_CTRL,
                       ISS_ISP5_CLKCTRL_MASK, clk);
}

void omap4iss_isp_subclk_enable(struct iss_device *iss,
                                enum iss_isp_subclk_resource res)
{
        iss->isp_subclk_resources |= res;

        __iss_isp_subclk_update(iss);
}

void omap4iss_isp_subclk_disable(struct iss_device *iss,
                                 enum iss_isp_subclk_resource res)
{
        iss->isp_subclk_resources &= ~res;

        __iss_isp_subclk_update(iss);
}

/*
 * iss_enable_clocks - Enable ISS clocks
 * @iss: OMAP4 ISS device
 *
 * Return 0 if successful, or clk_enable return value if any of tthem fails.
 */
static int iss_enable_clocks(struct iss_device *iss)
{
        int ret;

        ret = clk_enable(iss->iss_fck);
        if (ret) {
                dev_err(iss->dev, "clk_enable iss_fck failed\n");
                return ret;
        }

        ret = clk_enable(iss->iss_ctrlclk);
        if (ret) {
                dev_err(iss->dev, "clk_enable iss_ctrlclk failed\n");
                clk_disable(iss->iss_fck);
                return ret;
        }

        return 0;
}

/*
 * iss_disable_clocks - Disable ISS clocks
 * @iss: OMAP4 ISS device
 */
static void iss_disable_clocks(struct iss_device *iss)
{
        clk_disable(iss->iss_ctrlclk);
        clk_disable(iss->iss_fck);
}

static int iss_get_clocks(struct iss_device *iss)
{
        iss->iss_fck = devm_clk_get(iss->dev, "iss_fck");
        if (IS_ERR(iss->iss_fck)) {
                dev_err(iss->dev, "Unable to get iss_fck clock info\n");
                return PTR_ERR(iss->iss_fck);
        }

        iss->iss_ctrlclk = devm_clk_get(iss->dev, "iss_ctrlclk");
        if (IS_ERR(iss->iss_ctrlclk)) {
                dev_err(iss->dev, "Unable to get iss_ctrlclk clock info\n");
                return PTR_ERR(iss->iss_ctrlclk);
        }

        return 0;
}

/*
 * omap4iss_get - Acquire the ISS resource.
 *
 * Initializes the clocks for the first acquire.
 *
 * Increment the reference count on the ISS. If the first reference is taken,
 * enable clocks and power-up all submodules.
 *
 * Return a pointer to the ISS device structure, or NULL if an error occurred.
 */
struct iss_device *omap4iss_get(struct iss_device *iss)
{
        struct iss_device *__iss = iss;

        if (!iss)
                return NULL;

        mutex_lock(&iss->iss_mutex);
        if (iss->ref_count > 0)
                goto out;

        if (iss_enable_clocks(iss) < 0) {
                __iss = NULL;
                goto out;
        }

        iss_enable_interrupts(iss);

out:
        if (__iss)
                iss->ref_count++;
        mutex_unlock(&iss->iss_mutex);

        return __iss;
}

/*
 * omap4iss_put - Release the ISS
 *
 * Decrement the reference count on the ISS. If the last reference is released,
 * power-down all submodules, disable clocks and free temporary buffers.
 */
void omap4iss_put(struct iss_device *iss)
{
        if (!iss)
                return;

        mutex_lock(&iss->iss_mutex);
        WARN_ON(iss->ref_count == 0);
        if (--iss->ref_count == 0) {
                iss_disable_interrupts(iss);
                /* Reset the ISS if an entity has failed to stop. This is the
                 * only way to recover from such conditions, although it would
                 * be worth investigating whether resetting the ISP only can't
                 * fix the problem in some cases.
                 */
                if (!media_entity_enum_empty(&iss->crashed))
                        iss_reset(iss);
                iss_disable_clocks(iss);
        }
        mutex_unlock(&iss->iss_mutex);
}

static int iss_map_mem_resource(struct platform_device *pdev,
                                struct iss_device *iss,
                                enum iss_mem_resources res)
{
        iss->regs[res] = devm_platform_ioremap_resource(pdev, res);

        return PTR_ERR_OR_ZERO(iss->regs[res]);
}

static void iss_unregister_entities(struct iss_device *iss)
{
        omap4iss_resizer_unregister_entities(&iss->resizer);
        omap4iss_ipipe_unregister_entities(&iss->ipipe);
        omap4iss_ipipeif_unregister_entities(&iss->ipipeif);
        omap4iss_csi2_unregister_entities(&iss->csi2a);
        omap4iss_csi2_unregister_entities(&iss->csi2b);

        v4l2_device_unregister(&iss->v4l2_dev);
        media_device_unregister(&iss->media_dev);
}

/*
 * iss_register_subdev_group - Register a group of subdevices
 * @iss: OMAP4 ISS device
 * @board_info: I2C subdevs board information array
 *
 * Register all I2C subdevices in the board_info array. The array must be
 * terminated by a NULL entry, and the first entry must be the sensor.
 *
 * Return a pointer to the sensor media entity if it has been successfully
 * registered, or NULL otherwise.
 */
static struct v4l2_subdev *
iss_register_subdev_group(struct iss_device *iss,
                          struct iss_subdev_i2c_board_info *board_info)
{
        struct v4l2_subdev *sensor = NULL;
        unsigned int first;

        if (!board_info->board_info)
                return NULL;

        for (first = 1; board_info->board_info; ++board_info, first = 0) {
                struct v4l2_subdev *subdev;
                struct i2c_adapter *adapter;

                adapter = i2c_get_adapter(board_info->i2c_adapter_id);
                if (!adapter) {
                        dev_err(iss->dev,
                                "%s: Unable to get I2C adapter %d for device %s\n",
                                __func__, board_info->i2c_adapter_id,
                                board_info->board_info->type);
                        continue;
                }

                subdev = v4l2_i2c_new_subdev_board(&iss->v4l2_dev, adapter,
                                                   board_info->board_info, NULL);
                if (!subdev) {
                        dev_err(iss->dev, "Unable to register subdev %s\n",
                                board_info->board_info->type);
                        continue;
                }

                if (first)
                        sensor = subdev;
        }

        return sensor;
}

static int iss_register_entities(struct iss_device *iss)
{
        struct iss_platform_data *pdata = iss->pdata;
        struct iss_v4l2_subdevs_group *subdevs;
        int ret;

        iss->media_dev.dev = iss->dev;
        strscpy(iss->media_dev.model, "TI OMAP4 ISS",
                sizeof(iss->media_dev.model));
        iss->media_dev.hw_revision = iss->revision;
        iss->media_dev.ops = &iss_media_ops;
        ret = media_device_register(&iss->media_dev);
        if (ret < 0) {
                dev_err(iss->dev, "Media device registration failed (%d)\n",
                        ret);
                return ret;
        }

        iss->v4l2_dev.mdev = &iss->media_dev;

        ret = v4l2_device_register(iss->dev, &iss->v4l2_dev);
        if (ret < 0) {
                dev_err(iss->dev, "V4L2 device registration failed (%d)\n",
                        ret);
                goto done;
        }

        /* Register internal entities */
        ret = omap4iss_csi2_register_entities(&iss->csi2a, &iss->v4l2_dev);
        if (ret < 0)
                goto done;

        ret = omap4iss_csi2_register_entities(&iss->csi2b, &iss->v4l2_dev);
        if (ret < 0)
                goto done;

        ret = omap4iss_ipipeif_register_entities(&iss->ipipeif, &iss->v4l2_dev);
        if (ret < 0)
                goto done;

        ret = omap4iss_ipipe_register_entities(&iss->ipipe, &iss->v4l2_dev);
        if (ret < 0)
                goto done;

        ret = omap4iss_resizer_register_entities(&iss->resizer, &iss->v4l2_dev);
        if (ret < 0)
                goto done;

        /* Register external entities */
        for (subdevs = pdata->subdevs; subdevs && subdevs->subdevs; ++subdevs) {
                struct v4l2_subdev *sensor;
                struct media_entity *input;
                unsigned int flags;
                unsigned int pad;

                sensor = iss_register_subdev_group(iss, subdevs->subdevs);
                if (!sensor)
                        continue;

                sensor->host_priv = subdevs;

                /* Connect the sensor to the correct interface module.
                 * CSI2a receiver through CSIPHY1, or
                 * CSI2b receiver through CSIPHY2
                 */
                switch (subdevs->interface) {
                case ISS_INTERFACE_CSI2A_PHY1:
                        input = &iss->csi2a.subdev.entity;
                        pad = CSI2_PAD_SINK;
                        flags = MEDIA_LNK_FL_IMMUTABLE
                              | MEDIA_LNK_FL_ENABLED;
                        break;

                case ISS_INTERFACE_CSI2B_PHY2:
                        input = &iss->csi2b.subdev.entity;
                        pad = CSI2_PAD_SINK;
                        flags = MEDIA_LNK_FL_IMMUTABLE
                              | MEDIA_LNK_FL_ENABLED;
                        break;

                default:
                        dev_err(iss->dev, "invalid interface type %u\n",
                                subdevs->interface);
                        ret = -EINVAL;
                        goto done;
                }

                ret = media_create_pad_link(&sensor->entity, 0, input, pad,
                                            flags);
                if (ret < 0)
                        goto done;
        }

        ret = v4l2_device_register_subdev_nodes(&iss->v4l2_dev);

done:
        if (ret < 0)
                iss_unregister_entities(iss);

        return ret;
}

/*
 * iss_create_links() - Pads links creation for the subdevices
 * @iss : Pointer to ISS device
 *
 * return negative error code or zero on success
 */
static int iss_create_links(struct iss_device *iss)
{
        int ret;

        ret = omap4iss_csi2_create_links(iss);
        if (ret < 0) {
                dev_err(iss->dev, "CSI2 pads links creation failed\n");
                return ret;
        }

        ret = omap4iss_ipipeif_create_links(iss);
        if (ret < 0) {
                dev_err(iss->dev, "ISP IPIPEIF pads links creation failed\n");
                return ret;
        }

        ret = omap4iss_resizer_create_links(iss);
        if (ret < 0) {
                dev_err(iss->dev, "ISP RESIZER pads links creation failed\n");
                return ret;
        }

        /* Connect the submodules. */
        ret = media_create_pad_link(
                        &iss->csi2a.subdev.entity, CSI2_PAD_SOURCE,
                        &iss->ipipeif.subdev.entity, IPIPEIF_PAD_SINK, 0);
        if (ret < 0)
                return ret;

        ret = media_create_pad_link(
                        &iss->csi2b.subdev.entity, CSI2_PAD_SOURCE,
                        &iss->ipipeif.subdev.entity, IPIPEIF_PAD_SINK, 0);
        if (ret < 0)
                return ret;

        ret = media_create_pad_link(
                        &iss->ipipeif.subdev.entity, IPIPEIF_PAD_SOURCE_VP,
                        &iss->resizer.subdev.entity, RESIZER_PAD_SINK, 0);
        if (ret < 0)
                return ret;

        ret = media_create_pad_link(
                        &iss->ipipeif.subdev.entity, IPIPEIF_PAD_SOURCE_VP,
                        &iss->ipipe.subdev.entity, IPIPE_PAD_SINK, 0);
        if (ret < 0)
                return ret;

        ret = media_create_pad_link(
                        &iss->ipipe.subdev.entity, IPIPE_PAD_SOURCE_VP,
                        &iss->resizer.subdev.entity, RESIZER_PAD_SINK, 0);
        if (ret < 0)
                return ret;

        return 0;
};

static void iss_cleanup_modules(struct iss_device *iss)
{
        omap4iss_csi2_cleanup(iss);
        omap4iss_ipipeif_cleanup(iss);
        omap4iss_ipipe_cleanup(iss);
        omap4iss_resizer_cleanup(iss);
}

static int iss_initialize_modules(struct iss_device *iss)
{
        int ret;

        ret = omap4iss_csiphy_init(iss);
        if (ret < 0) {
                dev_err(iss->dev, "CSI PHY initialization failed\n");
                goto error_csiphy;
        }

        ret = omap4iss_csi2_init(iss);
        if (ret < 0) {
                dev_err(iss->dev, "CSI2 initialization failed\n");
                goto error_csi2;
        }

        ret = omap4iss_ipipeif_init(iss);
        if (ret < 0) {
                dev_err(iss->dev, "ISP IPIPEIF initialization failed\n");
                goto error_ipipeif;
        }

        ret = omap4iss_ipipe_init(iss);
        if (ret < 0) {
                dev_err(iss->dev, "ISP IPIPE initialization failed\n");
                goto error_ipipe;
        }

        ret = omap4iss_resizer_init(iss);
        if (ret < 0) {
                dev_err(iss->dev, "ISP RESIZER initialization failed\n");
                goto error_resizer;
        }

        return 0;

error_resizer:
        omap4iss_ipipe_cleanup(iss);
error_ipipe:
        omap4iss_ipipeif_cleanup(iss);
error_ipipeif:
        omap4iss_csi2_cleanup(iss);
error_csi2:
error_csiphy:
        return ret;
}

static int iss_probe(struct platform_device *pdev)
{
        struct iss_platform_data *pdata = pdev->dev.platform_data;
        struct iss_device *iss;
        unsigned int i;
        int ret;

        if (!pdata)
                return -EINVAL;

        iss = devm_kzalloc(&pdev->dev, sizeof(*iss), GFP_KERNEL);
        if (!iss)
                return -ENOMEM;

        mutex_init(&iss->iss_mutex);

        iss->dev = &pdev->dev;
        iss->pdata = pdata;

        iss->raw_dmamask = DMA_BIT_MASK(32);
        iss->dev->dma_mask = &iss->raw_dmamask;
        iss->dev->coherent_dma_mask = DMA_BIT_MASK(32);

        platform_set_drvdata(pdev, iss);

        /*
         * TODO: When implementing DT support switch to syscon regmap lookup by
         * phandle.
         */
        iss->syscon = syscon_regmap_lookup_by_compatible("syscon");
        if (IS_ERR(iss->syscon)) {
                ret = PTR_ERR(iss->syscon);
                goto error;
        }

        /* Clocks */
        ret = iss_map_mem_resource(pdev, iss, OMAP4_ISS_MEM_TOP);
        if (ret < 0)
                goto error;

        ret = iss_get_clocks(iss);
        if (ret < 0)
                goto error;

        if (!omap4iss_get(iss)) {
                ret = -EINVAL;
                goto error;
        }

        ret = iss_reset(iss);
        if (ret < 0)
                goto error_iss;

        iss->revision = iss_reg_read(iss, OMAP4_ISS_MEM_TOP, ISS_HL_REVISION);
        dev_info(iss->dev, "Revision %08x found\n", iss->revision);

        for (i = 1; i < OMAP4_ISS_MEM_LAST; i++) {
                ret = iss_map_mem_resource(pdev, iss, i);
                if (ret)
                        goto error_iss;
        }

        /* Configure BTE BW_LIMITER field to max recommended value (1 GB) */
        iss_reg_update(iss, OMAP4_ISS_MEM_BTE, BTE_CTRL,
                       BTE_CTRL_BW_LIMITER_MASK,
                       18 << BTE_CTRL_BW_LIMITER_SHIFT);

        /* Perform ISP reset */
        ret = omap4iss_subclk_enable(iss, OMAP4_ISS_SUBCLK_ISP);
        if (ret < 0)
                goto error_iss;

        ret = iss_isp_reset(iss);
        if (ret < 0)
                goto error_iss;

        dev_info(iss->dev, "ISP Revision %08x found\n",
                 iss_reg_read(iss, OMAP4_ISS_MEM_ISP_SYS1, ISP5_REVISION));

        /* Interrupt */
        ret = platform_get_irq(pdev, 0);
        if (ret <= 0) {
                ret = -ENODEV;
                goto error_iss;
        }
        iss->irq_num = ret;

        if (devm_request_irq(iss->dev, iss->irq_num, iss_isr, IRQF_SHARED,
                             "OMAP4 ISS", iss)) {
                dev_err(iss->dev, "Unable to request IRQ\n");
                ret = -EINVAL;
                goto error_iss;
        }

        /* Entities */
        ret = iss_initialize_modules(iss);
        if (ret < 0)
                goto error_iss;

        ret = iss_register_entities(iss);
        if (ret < 0)
                goto error_modules;

        ret = media_entity_enum_init(&iss->crashed, &iss->media_dev);
        if (ret)
                goto error_entities;

        ret = iss_create_links(iss);
        if (ret < 0)
                goto error_entities;

        omap4iss_put(iss);

        return 0;

error_entities:
        iss_unregister_entities(iss);
        media_entity_enum_cleanup(&iss->crashed);
error_modules:
        iss_cleanup_modules(iss);
error_iss:
        omap4iss_put(iss);
error:
        mutex_destroy(&iss->iss_mutex);

        return ret;
}

static int iss_remove(struct platform_device *pdev)
{
        struct iss_device *iss = platform_get_drvdata(pdev);

        iss_unregister_entities(iss);
        media_entity_enum_cleanup(&iss->crashed);
        iss_cleanup_modules(iss);

        return 0;
}

static const struct platform_device_id omap4iss_id_table[] = {
        { "omap4iss", 0 },
        { },
};
MODULE_DEVICE_TABLE(platform, omap4iss_id_table);

static struct platform_driver iss_driver = {
        .probe          = iss_probe,
        .remove         = iss_remove,
        .id_table       = omap4iss_id_table,
        .driver = {
                .name   = "omap4iss",
        },
};

module_platform_driver(iss_driver);

MODULE_DESCRIPTION("TI OMAP4 ISS driver");
MODULE_AUTHOR("Sergio Aguirre <sergio.a.aguirre@gmail.com>");
MODULE_LICENSE("GPL");