/*
 * Brontes PCI frame grabber driver
 *
 * Copyright (C) 2008 3M Company
 * Contact: Justin Bronder <jsbronder@brontes3d.com>
 * Original Authors: Daniel Drake <ddrake@brontes3d.com>
 *                   Duane Griffin <duaneg@dghda.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */

#include <linux/device.h>
#include <linux/fs.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/ioctl.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/types.h>
#include <linux/cdev.h>
#include <linux/list.h>
#include <linux/poll.h>
#include <linux/wait.h>
#include <linux/mm.h>
#include <linux/uaccess.h>
#include <linux/sched.h>

static unsigned int b3dfg_nbuf = 2;

module_param_named(buffer_count, b3dfg_nbuf, uint, 0444);

MODULE_PARM_DESC(buffer_count, "Number of buffers (min 2, default 2)");

MODULE_AUTHOR("Daniel Drake <ddrake@brontes3d.com>");
MODULE_DESCRIPTION("Brontes frame grabber driver");
MODULE_LICENSE("GPL");

#define DRIVER_NAME "b3dfg"
#define B3DFG_MAX_DEVS 4
#define B3DFG_FRAMES_PER_BUFFER 3

#define B3DFG_BAR_REGS	0
#define B3DFG_REGS_LENGTH 0x10000

#define B3DFG_IOC_MAGIC		0xb3 /* dfg :-) */
#define B3DFG_IOCGFRMSZ		_IOR(B3DFG_IOC_MAGIC, 1, int)
#define B3DFG_IOCTNUMBUFS	_IO(B3DFG_IOC_MAGIC, 2)
#define B3DFG_IOCTTRANS		_IO(B3DFG_IOC_MAGIC, 3)
#define B3DFG_IOCTQUEUEBUF	_IO(B3DFG_IOC_MAGIC, 4)
#define B3DFG_IOCTPOLLBUF	_IOWR(B3DFG_IOC_MAGIC, 5, struct b3dfg_poll)
#define B3DFG_IOCTWAITBUF	_IOWR(B3DFG_IOC_MAGIC, 6, struct b3dfg_wait)
#define B3DFG_IOCGWANDSTAT	_IOR(B3DFG_IOC_MAGIC, 7, int)

enum {
	/* number of 4kb pages per frame */
	B3D_REG_FRM_SIZE = 0x0,

	/* bit 0: set to enable interrupts
	 * bit 1: set to enable cable status change interrupts */
	B3D_REG_HW_CTRL = 0x4,

	/* bit 0-1 - 1-based ID of next pending frame transfer (0 = none)
	 * bit 2 indicates the previous DMA transfer has completed
	 * bit 3 indicates wand cable status change
	 * bit 8:15 - counter of number of discarded triplets */
	B3D_REG_DMA_STS = 0x8,

	/* bit 0: wand status (1 = present, 0 = disconnected) */
	B3D_REG_WAND_STS = 0xc,

	/* bus address for DMA transfers. lower 2 bits must be zero because DMA
	 * works with 32 bit word size. */
	B3D_REG_EC220_DMA_ADDR = 0x8000,

	/* bit 20:0 - number of 32 bit words to be transferred
	 * bit 21:31 - reserved */
	B3D_REG_EC220_TRF_SIZE = 0x8004,

	/* bit 0 - error bit
	 * bit 1 - interrupt bit (set to generate interrupt at end of transfer)
	 * bit 2 - start bit (set to start transfer)
	 * bit 3 - direction (0 = DMA_TO_DEVICE, 1 = DMA_FROM_DEVICE
	 * bit 4:31 - reserved */
	B3D_REG_EC220_DMA_STS = 0x8008,
};

enum b3dfg_buffer_state {
	B3DFG_BUFFER_POLLED = 0,
	B3DFG_BUFFER_PENDING,
	B3DFG_BUFFER_POPULATED,
};

struct b3dfg_buffer {
	unsigned char *frame[B3DFG_FRAMES_PER_BUFFER];
	struct list_head list;
	u8 state;
};

struct b3dfg_dev {

	/* no protection needed: all finalized at initialization time */
	struct pci_dev *pdev;
	struct cdev chardev;
	struct device *dev;
	void __iomem *regs;
	unsigned int frame_size;

	/*
	 * Protects buffer state, including buffer_queue, triplet_ready,
	 * cur_dma_frame_idx & cur_dma_frame_addr.
	 */
	spinlock_t buffer_lock;
	struct b3dfg_buffer *buffers;
	struct list_head buffer_queue;

	/* Last frame in triplet transferred (-1 if none). */
	int cur_dma_frame_idx;

	/* Current frame's address for DMA. */
	dma_addr_t cur_dma_frame_addr;

	/*
	 * Protects cstate_tstamp.
	 * Nests inside buffer_lock.
	 */
	spinlock_t cstate_lock;
	unsigned long cstate_tstamp;

	/*
	 * Protects triplets_dropped.
	 * Nests inside buffers_lock.
	 */
	spinlock_t triplets_dropped_lock;
	unsigned int triplets_dropped;

	wait_queue_head_t buffer_waitqueue;

	unsigned int transmission_enabled:1;
	unsigned int triplet_ready:1;
};

static u8 b3dfg_devices[B3DFG_MAX_DEVS];

static struct class *b3dfg_class;
static dev_t b3dfg_devt;

static const struct pci_device_id b3dfg_ids[] __devinitdata = {
	{ PCI_DEVICE(0x0b3d, 0x0001) },
	{ },
};

MODULE_DEVICE_TABLE(pci, b3dfg_ids);

/***** user-visible types *****/

struct b3dfg_poll {
	int buffer_idx;
	unsigned int triplets_dropped;
};

struct b3dfg_wait {
	int buffer_idx;
	unsigned int timeout;
	unsigned int triplets_dropped;
};

/**** register I/O ****/

static u32 b3dfg_read32(struct b3dfg_dev *fgdev, u16 reg)
{
	return ioread32(fgdev->regs + reg);
}

static void b3dfg_write32(struct b3dfg_dev *fgdev, u16 reg, u32 value)
{
	iowrite32(value, fgdev->regs + reg);
}

/**** buffer management ****/

/*
 * Program EC220 for transfer of a specific frame.
 * Called with buffer_lock held.
 */
static int setup_frame_transfer(struct b3dfg_dev *fgdev,
	struct b3dfg_buffer *buf,