/*
 * A driver for the CMOS camera controller in the Marvell 88ALP01 "cafe"
 * multifunction chip.  Currently works with the Omnivision OV7670
 * sensor.
 *
 * The data sheet for this device can be found at:
 *    http://www.marvell.com/products/pc_connectivity/88alp01/
 *
 * Copyright 2006-11 One Laptop Per Child Association, Inc.
 * Copyright 2006-11 Jonathan Corbet <corbet@lwn.net>
 *
 * Written by Jonathan Corbet, corbet@lwn.net.
 *
 * v4l2_device/v4l2_subdev conversion by:
 * Copyright (C) 2009 Hans Verkuil <hverkuil@xs4all.nl>
 *
 * This file may be distributed under the terms of the GNU General
 * Public License, version 2.
 */
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/pci.h>
#include <linux/i2c.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <linux/videodev2.h>
#include <media/v4l2-device.h>
#include <linux/device.h>
#include <linux/wait.h>
#include <linux/delay.h>
#include <linux/io.h>

#include "mcam-core.h"

#define CAFE_VERSION 0x000002


/*
 * Parameters.
 */
MODULE_AUTHOR("Jonathan Corbet <corbet@lwn.net>");
MODULE_DESCRIPTION("Marvell 88ALP01 CMOS Camera Controller driver");
MODULE_LICENSE("GPL");
MODULE_SUPPORTED_DEVICE("Video");




struct cafe_camera {
        int registered;                 /* Fully initialized? */
        struct mcam_camera mcam;
        struct pci_dev *pdev;
        wait_queue_head_t smbus_wait;   /* Waiting on i2c events */
};

/*
 * Most of the camera controller registers are defined in mcam-core.h,
 * but the Cafe platform has some additional registers of its own;
 * they are described here.
 */

/*
 * "General purpose register" has a couple of GPIOs used for sensor
 * power and reset on OLPC XO 1.0 systems.
 */
#define REG_GPR         0xb4
#define   GPR_C1EN        0x00000020    /* Pad 1 (power down) enable */
#define   GPR_C0EN        0x00000010    /* Pad 0 (reset) enable */
#define   GPR_C1          0x00000002    /* Control 1 value */
/*
 * Control 0 is wired to reset on OLPC machines.  For ov7x sensors,
 * it is active low.
 */
#define   GPR_C0          0x00000001    /* Control 0 value */

/*
 * These registers control the SMBUS module for communicating
 * with the sensor.
 */
#define REG_TWSIC0      0xb8    /* TWSI (smbus) control 0 */
#define   TWSIC0_EN       0x00000001    /* TWSI enable */
#define   TWSIC0_MODE     0x00000002    /* 1 = 16-bit, 0 = 8-bit */
#define   TWSIC0_SID      0x000003fc    /* Slave ID */
/*
 * Subtle trickery: the slave ID field starts with bit 2.  But the
 * Linux i2c stack wants to treat the bottommost bit as a separate
 * read/write bit, which is why slave ID's are usually presented
 * >>1.  For consistency with that behavior, we shift over three
 * bits instead of two.
 */
#define   TWSIC0_SID_SHIFT 3
#define   TWSIC0_CLKDIV   0x0007fc00    /* Clock divider */
#define   TWSIC0_MASKACK  0x00400000    /* Mask ack from sensor */
#define   TWSIC0_OVMAGIC  0x00800000    /* Make it work on OV sensors */

#define REG_TWSIC1      0xbc    /* TWSI control 1 */
#define   TWSIC1_DATA     0x0000ffff    /* Data to/from camchip */
#define   TWSIC1_ADDR     0x00ff0000    /* Address (register) */
#define   TWSIC1_ADDR_SHIFT 16
#define   TWSIC1_READ     0x01000000    /* Set for read op */
#define   TWSIC1_WSTAT    0x02000000    /* Write status */
#define   TWSIC1_RVALID   0x04000000    /* Read data valid */
#define   TWSIC1_ERROR    0x08000000    /* Something screwed up */

/*
 * Here's the weird global control registers
 */
#define REG_GL_CSR     0x3004  /* Control/status register */
#define   GCSR_SRS       0x00000001     /* SW Reset set */
#define   GCSR_SRC       0x00000002     /* SW Reset clear */
#define   GCSR_MRS       0x00000004     /* Master reset set */
#define   GCSR_MRC       0x00000008     /* HW Reset clear */
#define   GCSR_CCIC_EN   0x00004000    /* CCIC Clock enable */
#define REG_GL_IMASK   0x300c  /* Interrupt mask register */
#define   GIMSK_CCIC_EN          0x00000004    /* CCIC Interrupt enable */

#define REG_GL_FCR      0x3038  /* GPIO functional control register */
#define   GFCR_GPIO_ON    0x08          /* Camera GPIO enabled */
#define REG_GL_GPIOR    0x315c  /* GPIO register */
#define   GGPIO_OUT             0x80000 /* GPIO output */
#define   GGPIO_VAL             0x00008 /* Output pin value */

#define REG_LEN                (REG_GL_IMASK + 4)


/*
 * Debugging and related.
 */
#define cam_err(cam, fmt, arg...) \
        dev_err(&(cam)->pdev->dev, fmt, ##arg);
#define cam_warn(cam, fmt, arg...) \
        dev_warn(&(cam)->pdev->dev, fmt, ##arg);

/* -------------------------------------------------------------------- */
/*
 * The I2C/SMBUS interface to the camera itself starts here.  The
 * controller handles SMBUS itself, presenting a relatively simple register
 * interface; all we have to do is to tell it where to route the data.
 */
#define CAFE_SMBUS_TIMEOUT (HZ)  /* generous */

static inline struct cafe_camera *to_cam(struct v4l2_device *dev)
{
        struct mcam_camera *m = container_of(dev, struct mcam_camera, v4l2_dev);
        return container_of(m, struct cafe_camera, mcam);
}


static int cafe_smbus_write_done(struct mcam_camera *mcam)
{
        unsigned long flags;
        int c1;

        /*
         * We must delay after the interrupt, or the controller gets confused
         * and never does give us good status.  Fortunately, we don't do this
         * often.
         */
        udelay(20);
        spin_lock_irqsave(&mcam->dev_lock, flags);
        c1 = mcam_reg_read(mcam, REG_TWSIC1);
        spin_unlock_irqrestore(&mcam->dev_lock, flags);
        return (c1 & (TWSIC1_WSTAT|TWSIC1_ERROR)) != TWSIC1_WSTAT;
}

static int cafe_smbus_write_data(struct cafe_camera *cam,
                u16 addr, u8 command, u8 value)
{
        unsigned int rval;
        unsigned long flags;
        struct mcam_camera *mcam = &cam->mcam;

        spin_lock_irqsave(&mcam->dev_lock, flags);
        rval = TWSIC0_EN | ((addr << TWSIC0_SID_SHIFT) & TWSIC0_SID);
        rval |= TWSIC0_OVMAGIC;  /* Make OV sensors work */
        /*
         * Marvell sez set clkdiv to all 1's for now.
         */
        rval |= TWSIC0_CLKDIV;
        mcam_reg_write(mcam, REG_TWSIC0, rval);
        (void) mcam_reg_read(mcam, REG_TWSIC1); /* force write */
        rval = value | ((command << TWSIC1_ADDR_SHIFT) & TWSIC1_ADDR);
        mcam_reg_write(mcam, REG_TWSIC1, rval);
        spin_unlock_irqrestore(&mcam->dev_lock, flags);

        /* Unfortunately, reading TWSIC1 too soon after sending a command
         * causes the device to die.
         * Use a busy-wait because we often send a large quantity of small
         * commands at-once; using msleep() would cause a lot of context
         * switches which take longer than 2ms, resulting in a noticeable
         * boot-time and capture-start delays.
         */
        mdelay(2);

        /*
         * Another sad fact is that sometimes, commands silently complete but
         * cafe_smbus_write_done() never becomes aware of this.
         * This happens at random and appears to possible occur with any
         * command.
         * We don't understand why this is. We work around this issue
         * with the timeout in the wait below, assuming that all commands
         * complete within the timeout.
         */
        wait_event_timeout(cam->smbus_wait, cafe_smbus_write_done(mcam),
                        CAFE_SMBUS_TIMEOUT);

        spin_lock_irqsave(&mcam->dev_lock, flags);
        rval = mcam_reg_read(mcam, REG_TWSIC1);
        spin_unlock_irqrestore(&mcam->dev_lock, flags);

        if (rval & TWSIC1_WSTAT) {
                cam_err(cam, "SMBUS write (%02x/%02x/%02x) timed out\n", addr,
                                command, value);
                return -EIO;
        }
        if (rval & TWSIC1_ERROR) {
                cam_err(cam, "SMBUS write (%02x/%02x/%02x) error\n", addr,
                                command, value);
                return -EIO;
        }
        return 0;
}



static int cafe_smbus_read_done(struct mcam_camera *mcam)
{
        unsigned long flags;
        int c1;

        /*
         * We must delay after the interrupt, or the controller gets confused
         * and never does give us good status.  Fortunately, we don't do this
         * often.
         */
        udelay(20);
        spin_lock_irqsave(&mcam->dev_lock, flags);
        c1 = mcam_reg_read(mcam, REG_TWSIC1);
        spin_unlock_irqrestore(&mcam->dev_lock, flags);
        return c1 & (TWSIC1_RVALID|TWSIC1_ERROR);
}



static int cafe_smbus_read_data(struct cafe_camera *cam,
                u16 addr, u8 command, u8 *value)
{
        unsigned int rval;
        unsigned long flags;
        struct mcam_camera *mcam = &cam->mcam;

        spin_lock_irqsave(&mcam->dev_lock, flags);
        rval = TWSIC0_EN | ((addr << TWSIC0_SID_SHIFT) & TWSIC0_SID);
        rval |= TWSIC0_OVMAGIC; /* Make OV sensors work */
        /*
         * Marvel sez set clkdiv to all 1's for now.
         */
        rval |= TWSIC0_CLKDIV;
        mcam_reg_write(mcam, REG_TWSIC0, rval);
        (void) mcam_reg_read(mcam, REG_TWSIC1); /* force write */
        rval = TWSIC1_READ | ((command << TWSIC1_ADDR_SHIFT) & TWSIC1_ADDR);
        mcam_reg_write(mcam, REG_TWSIC1, rval);
        spin_unlock_irqrestore(&mcam->dev_lock, flags);

        wait_event_timeout(cam->smbus_wait,
                        cafe_smbus_read_done(mcam), CAFE_SMBUS_TIMEOUT);
        spin_lock_irqsave(&mcam->dev_lock, flags);
        rval = mcam_reg_read(mcam, REG_TWSIC1);
        spin_unlock_irqrestore(&mcam->dev_lock, flags);

        if (rval & TWSIC1_ERROR) {
                cam_err(cam, "SMBUS read (%02x/%02x) error\n", addr, command);
                return -EIO;
        }
        if (!(rval & TWSIC1_RVALID)) {
                cam_err(cam, "SMBUS read (%02x/%02x) timed out\n", addr,
                                command);
                return -EIO;
        }
        *value = rval & 0xff;
        return 0;
}

/*
 * Perform a transfer over SMBUS.  This thing is called under
 * the i2c bus lock, so we shouldn't race with ourselves...
 */
static int cafe_smbus_xfer(struct i2c_adapter *adapter, u16 addr,
                unsigned short flags, char rw, u8 command,
                int size, union i2c_smbus_data *data)
{
        struct cafe_camera *cam = i2c_get_adapdata(adapter);
        int ret = -EINVAL;

        /*
         * This interface would appear to only do byte data ops.  OK
         * it can do word too, but the cam chip has no use for that.
         */
        if (size != I2C_SMBUS_BYTE_DATA) {
                cam_err(cam, "funky xfer size %d\n", size);
                return -EINVAL;
        }

        if (rw == I2C_SMBUS_WRITE)
                ret = cafe_smbus_write_data(cam, addr, command, data->byte);
        else if (rw == I2C_SMBUS_READ)
                ret = cafe_smbus_read_data(cam, addr, command, &data->byte);
        return ret;
}


static void cafe_smbus_enable_irq(struct cafe_camera *cam)
{
        unsigned long flags;

        spin_lock_irqsave(&cam->mcam.dev_lock, flags);
        mcam_reg_set_bit(&cam->mcam, REG_IRQMASK, TWSIIRQS);
        spin_unlock_irqrestore(&cam->mcam.dev_lock, flags);
}

static u32 cafe_smbus_func(struct i2c_adapter *adapter)
{
        return I2C_FUNC_SMBUS_READ_BYTE_DATA  |
               I2C_FUNC_SMBUS_WRITE_BYTE_DATA;
}

static struct i2c_algorithm cafe_smbus_algo = {
        .smbus_xfer = cafe_smbus_xfer,
        .functionality = cafe_smbus_func
};

static int cafe_smbus_setup(struct cafe_camera *cam)
{
        struct i2c_adapter *adap;
        int ret;

        adap = kzalloc(sizeof(*adap), GFP_KERNEL);
        if (adap == NULL)
                return -ENOMEM;
        cam->mcam.i2c_adapter = adap;
        cafe_smbus_enable_irq(cam);
        adap->owner = THIS_MODULE;
        adap->algo = &cafe_smbus_algo;
        strcpy(adap->name, "cafe_ccic");
        adap->dev.parent = &cam->pdev->dev;
        i2c_set_adapdata(adap, cam);
        ret = i2c_add_adapter(adap);
        if (ret)
                printk(KERN_ERR "Unable to register cafe i2c adapter\n");
        return ret;
}

static void cafe_smbus_shutdown(struct cafe_camera *cam)
{
        i2c_del_adapter(cam->mcam.i2c_adapter);
        kfree(cam->mcam.i2c_adapter);
}


/*
 * Controller-level stuff
 */

static void cafe_ctlr_init(struct mcam_camera *mcam)
{
        unsigned long flags;

        spin_lock_irqsave(&mcam->dev_lock, flags);
        /*
         * Added magic to bring up the hardware on the B-Test board
         */
        mcam_reg_write(mcam, 0x3038, 0x8);
        mcam_reg_write(mcam, 0x315c, 0x80008);
        /*
         * Go through the dance needed to wake the device up.
         * Note that these registers are global and shared
         * with the NAND and SD devices.  Interaction between the
         * three still needs to be examined.
         */
        mcam_reg_write(mcam, REG_GL_CSR, GCSR_SRS|GCSR_MRS); /* Needed? */
        mcam_reg_write(mcam, REG_GL_CSR, GCSR_SRC|GCSR_MRC);
        mcam_reg_write(mcam, REG_GL_CSR, GCSR_SRC|GCSR_MRS);
        /*
         * Here we must wait a bit for the controller to come around.
         */
        spin_unlock_irqrestore(&mcam->dev_lock, flags);
        msleep(5);
        spin_lock_irqsave(&mcam->dev_lock, flags);

        mcam_reg_write(mcam, REG_GL_CSR, GCSR_CCIC_EN|GCSR_SRC|GCSR_MRC);
        mcam_reg_set_bit(mcam, REG_GL_IMASK, GIMSK_CCIC_EN);
        /*
         * Mask all interrupts.
         */
        mcam_reg_write(mcam, REG_IRQMASK, 0);
        spin_unlock_irqrestore(&mcam->dev_lock, flags);
}


static void cafe_ctlr_power_up(struct mcam_camera *mcam)
{
        /*
         * Part one of the sensor dance: turn the global
         * GPIO signal on.
         */
        mcam_reg_write(mcam, REG_GL_FCR, GFCR_GPIO_ON);
        mcam_reg_write(mcam, REG_GL_GPIOR, GGPIO_OUT|GGPIO_VAL);
        /*
         * Put the sensor into operational mode (assumes OLPC-style
         * wiring).  Control 0 is reset - set to 1 to operate.
         * Control 1 is power down, set to 0 to operate.
         */
        mcam_reg_write(mcam, REG_GPR, GPR_C1EN|GPR_C0EN); /* pwr up, reset */
        mcam_reg_write(mcam, REG_GPR, GPR_C1EN|GPR_C0EN|GPR_C0);
}

static void cafe_ctlr_power_down(struct mcam_camera *mcam)
{
        mcam_reg_write(mcam, REG_GPR, GPR_C1EN|GPR_C0EN|GPR_C1);
        mcam_reg_write(mcam, REG_GL_FCR, GFCR_GPIO_ON);
        mcam_reg_write(mcam, REG_GL_GPIOR, GGPIO_OUT);
}



/*
 * The platform interrupt handler.
 */
static irqreturn_t cafe_irq(int irq, void *data)
{
        struct cafe_camera *cam = data;
        struct mcam_camera *mcam = &cam->mcam;
        unsigned int irqs, handled;

        spin_lock(&mcam->dev_lock);
        irqs = mcam_reg_read(mcam, REG_IRQSTAT);
        handled = cam->registered && mccic_irq(mcam, irqs);
        if (irqs & TWSIIRQS) {
                mcam_reg_write(mcam, REG_IRQSTAT, TWSIIRQS);
                wake_up(&cam->smbus_wait);
                handled = 1;
        }
        spin_unlock(&mcam->dev_lock);
        return IRQ_RETVAL(handled);
}


/* -------------------------------------------------------------------------- */
/*
 * PCI interface stuff.
 */

static int cafe_pci_probe(struct pci_dev *pdev,
                const struct pci_device_id *id)
{
        int ret;
        struct cafe_camera *cam;
        struct mcam_camera *mcam;

        /*
         * Start putting together one of our big camera structures.
         */
        ret = -ENOMEM;
        cam = kzalloc(sizeof(struct cafe_camera), GFP_KERNEL);
        if (cam == NULL)
                goto out;
        cam->pdev = pdev;
        mcam = &cam->mcam;
        mcam->chip_id = MCAM_CAFE;
        spin_lock_init(&mcam->dev_lock);
        init_waitqueue_head(&cam->smbus_wait);
        mcam->plat_power_up = cafe_ctlr_power_up;
        mcam->plat_power_down = cafe_ctlr_power_down;
        mcam->dev = &pdev->dev;
        /*
         * Set the clock speed for the XO 1; I don't believe this
         * driver has ever run anywhere else.
         */
        mcam->clock_speed = 45;
        mcam->use_smbus = 1;
        /*
         * Vmalloc mode for buffers is traditional with this driver.
         * We *might* be able to run DMA_contig, especially on a system
         * with CMA in it.
         */
        mcam->buffer_mode = B_vmalloc;
        /*
         * Get set up on the PCI bus.
         */
        ret = pci_enable_device(pdev);
        if (ret)
                goto out_free;
        pci_set_master(pdev);

        ret = -EIO;
        mcam->regs = pci_iomap(pdev, 0, 0);
        if (!mcam->regs) {
                printk(KERN_ERR "Unable to ioremap cafe-ccic regs\n");
                goto out_disable;
        }
        mcam->regs_size = pci_resource_len(pdev, 0);
        ret = request_irq(pdev->irq, cafe_irq, IRQF_SHARED, "cafe-ccic", cam);
        if (ret)
                goto out_iounmap;

        /*
         * Initialize the controller and leave it powered up.  It will
         * stay that way until the sensor driver shows up.
         */
        cafe_ctlr_init(mcam);
        cafe_ctlr_power_up(mcam);
        /*
         * Set up I2C/SMBUS communications.  We have to drop the mutex here
         * because the sensor could attach in this call chain, leading to
         * unsightly deadlocks.
         */
        ret = cafe_smbus_setup(cam);
        if (ret)
                goto out_pdown;

        ret = mccic_register(mcam);
        if (ret == 0) {
                cam->registered = 1;
                return 0;
        }

        cafe_smbus_shutdown(cam);
out_pdown:
        cafe_ctlr_power_down(mcam);
        free_irq(pdev->irq, cam);
out_iounmap:
        pci_iounmap(pdev, mcam->regs);
out_disable:
        pci_disable_device(pdev);
out_free:
        kfree(cam);
out:
        return ret;
}


/*
 * Shut down an initialized device
 */
static void cafe_shutdown(struct cafe_camera *cam)
{
        mccic_shutdown(&cam->mcam);
        cafe_smbus_shutdown(cam);
        free_irq(cam->pdev->irq, cam);
        pci_iounmap(cam->pdev, cam->mcam.regs);
}


static void cafe_pci_remove(struct pci_dev *pdev)
{
        struct v4l2_device *v4l2_dev = dev_get_drvdata(&pdev->dev);
        struct cafe_camera *cam = to_cam(v4l2_dev);

        if (cam == NULL) {
                printk(KERN_WARNING "pci_remove on unknown pdev %p\n", pdev);
                return;
        }
        cafe_shutdown(cam);
        kfree(cam);
}


#ifdef CONFIG_PM
/*
 * Basic power management.
 */
static int cafe_pci_suspend(struct pci_dev *pdev, pm_message_t state)
{
        struct v4l2_device *v4l2_dev = dev_get_drvdata(&pdev->dev);
        struct cafe_camera *cam = to_cam(v4l2_dev);
        int ret;

        ret = pci_save_state(pdev);
        if (ret)
                return ret;
        mccic_suspend(&cam->mcam);
        pci_disable_device(pdev);
        return 0;
}


static int cafe_pci_resume(struct pci_dev *pdev)
{
        struct v4l2_device *v4l2_dev = dev_get_drvdata(&pdev->dev);
        struct cafe_camera *cam = to_cam(v4l2_dev);
        int ret = 0;

        pci_restore_state(pdev);
        ret = pci_enable_device(pdev);

        if (ret) {
                cam_warn(cam, "Unable to re-enable device on resume!\n");
                return ret;
        }
        cafe_ctlr_init(&cam->mcam);
        return mccic_resume(&cam->mcam);
}

#endif  /* CONFIG_PM */

static struct pci_device_id cafe_ids[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_MARVELL,
                     PCI_DEVICE_ID_MARVELL_88ALP01_CCIC) },
        { 0, }
};

MODULE_DEVICE_TABLE(pci, cafe_ids);

static struct pci_driver cafe_pci_driver = {
        .name = "cafe1000-ccic",
        .id_table = cafe_ids,
        .probe = cafe_pci_probe,
        .remove = cafe_pci_remove,
#ifdef CONFIG_PM
        .suspend = cafe_pci_suspend,
        .resume = cafe_pci_resume,
#endif
};




static int __init cafe_init(void)
{
        int ret;

        printk(KERN_NOTICE "Marvell M88ALP01 'CAFE' Camera Controller version %d\n",
                        CAFE_VERSION);
        ret = pci_register_driver(&cafe_pci_driver);
        if (ret) {
                printk(KERN_ERR "Unable to register cafe_ccic driver\n");
                goto out;
        }
        ret = 0;

out:
        return ret;
}


static void __exit cafe_exit(void)
{
        pci_unregister_driver(&cafe_pci_driver);
}

module_init(cafe_init);
module_exit(cafe_exit);