// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (c) 2019 MediaTek Inc.
 */

#include <linux/cdev.h>
#include <linux/gpio.h>
#include <linux/uaccess.h>
#include "synaptics_tcm_core.h"

#define CHAR_DEVICE_NAME "tcm"

#define CONCURRENT true

#define DEVICE_IOC_MAGIC 's'
#define DEVICE_IOC_RESET _IO(DEVICE_IOC_MAGIC, 0) /* 0x00007300 */
#define DEVICE_IOC_IRQ _IOW(DEVICE_IOC_MAGIC, 1, int) /* 0x40047301 */
#define DEVICE_IOC_RAW _IOW(DEVICE_IOC_MAGIC, 2, int) /* 0x40047302 */
#define DEVICE_IOC_CONCURRENT _IOW(DEVICE_IOC_MAGIC, 3, int) /* 0x40047303 */

struct device_hcd {
	dev_t dev_num;
	bool raw_mode;
	bool concurrent;
	unsigned int ref_count;
	struct cdev char_dev;
	struct class *class;
	struct device *device;
	struct syna_tcm_buffer out;
	struct syna_tcm_buffer resp;
	struct syna_tcm_buffer report;
	struct syna_tcm_hcd *tcm_hcd;
};

DECLARE_COMPLETION(device_remove_complete);

static struct device_hcd *device_hcd;

static int rmidev_major_num;

static void device_capture_touch_report(unsigned int count)
{
	int retval;
	unsigned char id;
	unsigned int idx;
	unsigned int size;
	unsigned char *data;
	struct syna_tcm_hcd *tcm_hcd = device_hcd->tcm_hcd;
	static bool report;
	static unsigned int offset;
	static unsigned int remaining_size;

	if (count < 2)
		return;

	data = &device_hcd->resp.buf[0];

	if (data[0] != MESSAGE_MARKER)
		return;

	id = data[1];

	size = 0;

	LOCK_BUFFER(device_hcd->report);

	switch (id) {
	case REPORT_TOUCH:
		if (count >= 4) {
			remaining_size = le2_to_uint(&data[2]);
		} else {
			report = false;
			goto exit;
		}
		retval = syna_tcm_alloc_mem(tcm_hcd,
				&device_hcd->report,
				remaining_size);
		if (retval < 0) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Failed to allocate memory for device_hcd->report.buf\n");
			report = false;
			goto exit;
		}
		idx = 4;
		size = count - idx;
		offset = 0;
		report = true;
		break;
	case STATUS_CONTINUED_READ:
		if (report == false)
			goto exit;
		if (count >= 2) {
			idx = 2;
			size = count - idx;
		}
		break;
	default:
		goto exit;
	}

	if (size) {
		size = MIN(size, remaining_size);
		retval = secure_memcpy(&device_hcd->report.buf[offset],
				device_hcd->report.buf_size - offset,
				&data[idx],
				count - idx,
				size);
		if (retval < 0) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Failed to copy touch report data\n");
			report = false;
			goto exit;
		} else {
			offset += size;
			remaining_size -= size;
			device_hcd->report.data_length += size;
		}
	}

	if (remaining_size)
		goto exit;

	LOCK_BUFFER(tcm_hcd->report.buffer);

	tcm_hcd->report.buffer.buf = device_hcd->report.buf;
	tcm_hcd->report.buffer.buf_size = device_hcd->report.buf_size;
	tcm_hcd->report.buffer.data_length = device_hcd->report.data_length;

	tcm_hcd->report_touch();

	UNLOCK_BUFFER(tcm_hcd->report.buffer);

	report = false;

exit:
	UNLOCK_BUFFER(device_hcd->report);
}

static int device_capture_touch_report_config(unsigned int count)
{
	int retval;
	unsigned int size;
	unsigned int buf_size;
	unsigned char *data;
	struct syna_tcm_hcd *tcm_hcd = device_hcd->tcm_hcd;

	if (device_hcd->raw_mode) {
		if (count < 3) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Invalid write data\n");
			return -EINVAL;
		}

		size = le2_to_uint(&device_hcd->out.buf[1]);

		if (count - 3 < size) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Incomplete write data\n");
			return -EINVAL;
		}

		if (!size)
			return 0;

		data = &device_hcd->out.buf[3];
		buf_size = device_hcd->out.buf_size - 3;
	} else {
		size = count - 1;

		if (!size)
			return 0;

		data = &device_hcd->out.buf[1];
		buf_size = device_hcd->out.buf_size - 1;
	}

	LOCK_BUFFER(tcm_hcd->config);

	retval = syna_tcm_alloc_mem(tcm_hcd,
			&tcm_hcd->config,
			size);
	if (retval < 0) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to allocate memory for tcm_hcd->config.buf\n");
		UNLOCK_BUFFER(tcm_hcd->config);
		return retval;
	}

	retval = secure_memcpy(tcm_hcd->config.buf,
			tcm_hcd->config.buf_size,
			data,
			buf_size,
			size);
	if (retval < 0) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to copy touch report config data\n");
		UNLOCK_BUFFER(tcm_hcd->config);
		return retval;
	}

	tcm_hcd->config.data_length = size;

	UNLOCK_BUFFER(tcm_hcd->config);

	return 0;
}

#ifdef HAVE_UNLOCKED_IOCTL
static long device_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
#else
static int device_ioctl(struct inode *inp, struct file *filp, unsigned int cmd,
		unsigned long arg)
#endif
{
	int retval;
	struct syna_tcm_hcd *tcm_hcd = device_hcd->tcm_hcd;

	mutex_lock(&tcm_hcd->extif_mutex);

	retval = 0;

	switch (cmd) {
	case DEVICE_IOC_RESET:
		retval = tcm_hcd->reset(tcm_hcd, false, true);
		break;
	case DEVICE_IOC_IRQ:
		if (arg == 0)
			retval = tcm_hcd->enable_irq(tcm_hcd, false, false);
		else if (arg == 1)
			retval = tcm_hcd->enable_irq(tcm_hcd, true, NULL);
		break;
	case DEVICE_IOC_RAW:
		if (arg == 0) {
			device_hcd->raw_mode = false;
			tcm_hcd->update_watchdog(tcm_hcd, true);
		} else if (arg == 1) {
			device_hcd->raw_mode = true;
			tcm_hcd->update_watchdog(tcm_hcd, false);
		}
		break;
	case DEVICE_IOC_CONCURRENT:
		if (arg == 0)
			device_hcd->concurrent = false;
		else if (arg == 1)
			device_hcd->concurrent = true;
		break;
	default:
		retval = -ENOTTY;
		break;
	}

	mutex_unlock(&tcm_hcd->extif_mutex);

	return retval;
}

static loff_t device_llseek(struct file *filp, loff_t off, int whence)
{
	return -EINVAL;
}

static ssize_t device_read(struct file *filp, char __user *buf,
		size_t count, loff_t *f_pos)
{
	int retval;
	struct syna_tcm_hcd *tcm_hcd = device_hcd->tcm_hcd;

	if (count == 0)
		return 0;

	mutex_lock(&tcm_hcd->extif_mutex);

	LOCK_BUFFER(device_hcd->resp);

	if (device_hcd->raw_mode) {
		retval = syna_tcm_alloc_mem(tcm_hcd,
				&device_hcd->resp,
				count);
		if (retval < 0) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Failed to allocate memory for device_hcd->resp.buf\n");
			UNLOCK_BUFFER(device_hcd->resp);
			goto exit;
		}
		retval = tcm_hcd->read_message(tcm_hcd,
				device_hcd->resp.buf,
				count);
		if (retval < 0) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Failed to read message\n");
			UNLOCK_BUFFER(device_hcd->resp);
			goto exit;
		}
	} else {
		if (count != device_hcd->resp.data_length) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Invalid length information\n");
			UNLOCK_BUFFER(device_hcd->resp);
			retval = -EINVAL;
			goto exit;
		}
	}

	if (copy_to_user(buf, device_hcd->resp.buf, count)) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to copy data to user space\n");
		UNLOCK_BUFFER(device_hcd->resp);
		retval = -EINVAL;
		goto exit;
	}

	if (!device_hcd->concurrent)
		goto skip_concurrent;

	if (tcm_hcd->report_touch == NULL) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Unable to report touch\n");
		device_hcd->concurrent = false;
	}

	if (device_hcd->raw_mode)
		device_capture_touch_report(count);

skip_concurrent:
	UNLOCK_BUFFER(device_hcd->resp);

	retval = count;

exit:
	mutex_unlock(&tcm_hcd->extif_mutex);

	return retval;
}

static ssize_t device_write(struct file *filp, const char __user *buf,
		size_t count, loff_t *f_pos)
{
	int retval;
	struct syna_tcm_hcd *tcm_hcd = device_hcd->tcm_hcd;

	if (count == 0)
		return 0;

	mutex_lock(&tcm_hcd->extif_mutex);

	LOCK_BUFFER(device_hcd->out);

	retval = syna_tcm_alloc_mem(tcm_hcd,
			&device_hcd->out,
			count == 1 ? count + 1 : count);
	if (retval < 0) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to allocate memory for device_hcd->out.buf\n");
		UNLOCK_BUFFER(device_hcd->out);
		goto exit;
	}

	if (copy_from_user(device_hcd->out.buf, buf, count)) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to copy data from user space\n");
		UNLOCK_BUFFER(device_hcd->out);
		retval = -EINVAL;
		goto exit;
	}

	LOCK_BUFFER(device_hcd->resp);

	if (device_hcd->raw_mode) {
		retval = tcm_hcd->write_message(tcm_hcd,
				device_hcd->out.buf[0],
				&device_hcd->out.buf[1],
				count - 1,
				NULL,
				NULL,
				NULL,
				NULL,
				0);
	} else {
		mutex_lock(&tcm_hcd->reset_mutex);
		retval = tcm_hcd->write_message(tcm_hcd,
				device_hcd->out.buf[0],
				&device_hcd->out.buf[1],
				count - 1,
				&device_hcd->resp.buf,
				&device_hcd->resp.buf_size,
				&device_hcd->resp.data_length,
				NULL,
				0);
		mutex_unlock(&tcm_hcd->reset_mutex);
	}
	if (retval < 0) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to write command 0x%02x\n",
				device_hcd->out.buf[0]);
		UNLOCK_BUFFER(device_hcd->resp);
		UNLOCK_BUFFER(device_hcd->out);
		goto exit;
	}

	if (count && device_hcd->out.buf[0] == CMD_SET_TOUCH_REPORT_CONFIG) {
		retval = device_capture_touch_report_config(count);
		if (retval < 0) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Failed to capture touch report config\n");
		}
	}

	UNLOCK_BUFFER(device_hcd->out);

	if (device_hcd->raw_mode)
		retval = count;
	else
		retval = device_hcd->resp.data_length;

	UNLOCK_BUFFER(device_hcd->resp);

exit:
	mutex_unlock(&tcm_hcd->extif_mutex);

	return retval;
}

static int device_open(struct inode *inp, struct file *filp)
{
	int retval;
	struct syna_tcm_hcd *tcm_hcd = device_hcd->tcm_hcd;

	mutex_lock(&tcm_hcd->extif_mutex);

	if (device_hcd->ref_count < 1) {
		device_hcd->ref_count++;
		retval = 0;
	} else {
		retval = -EACCES;
	}

	mutex_unlock(&tcm_hcd->extif_mutex);

	return retval;
}

static int device_release(struct inode *inp, struct file *filp)
{
	struct syna_tcm_hcd *tcm_hcd = device_hcd->tcm_hcd;

	mutex_lock(&tcm_hcd->extif_mutex);

	if (device_hcd->ref_count)
		device_hcd->ref_count--;

	mutex_unlock(&tcm_hcd->extif_mutex);

	return 0;
}

static char *device_devnode(struct device *dev, umode_t *mode)
{
	if (!mode)
		return NULL;

	*mode = 0666;

	return kasprintf(GFP_KERNEL, "%s/%s", PLATFORM_DRIVER_NAME,
			dev_name(dev));
}

static int device_create_class(void)
{
	struct syna_tcm_hcd *tcm_hcd = device_hcd->tcm_hcd;

	if (device_hcd->class != NULL)
		return 0;

	device_hcd->class = class_create(THIS_MODULE, PLATFORM_DRIVER_NAME);

	if (IS_ERR(device_hcd->class)) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to create class\n");
		return -ENODEV;
	}

	device_hcd->class->devnode = device_devnode;

	return 0;
}

static const struct file_operations device_fops = {
	.owner = THIS_MODULE,
#ifdef HAVE_UNLOCKED_IOCTL
	.unlocked_ioctl = device_ioctl,
#ifdef HAVE_COMPAT_IOCTL
	.compat_ioctl = device_ioctl,
#endif
#else
	.ioctl = device_ioctl,
#endif
	.llseek = device_llseek,
	.read = device_read,
	.write = device_write,
	.open = device_open,
	.release = device_release,
};

static int device_init(struct syna_tcm_hcd *tcm_hcd)
{
	int retval;
	dev_t dev_num;
	const struct syna_tcm_board_data *bdata = tcm_hcd->hw_if->bdata;

	device_hcd = kzalloc(sizeof(*device_hcd), GFP_KERNEL);
	if (!device_hcd) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to allocate memory for device_hcd\n");
		return -ENOMEM;
	}

	device_hcd->tcm_hcd = tcm_hcd;

	device_hcd->concurrent = CONCURRENT;

	INIT_BUFFER(device_hcd->out, false);
	INIT_BUFFER(device_hcd->resp, false);
	INIT_BUFFER(device_hcd->report, false);

	if (rmidev_major_num) {
		dev_num = MKDEV(rmidev_major_num, 0);
		retval = register_chrdev_region(dev_num, 1,
				PLATFORM_DRIVER_NAME);
		if (retval < 0) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Failed to register char device\n");
			goto err_register_chrdev_region;
		}
	} else {
		retval = alloc_chrdev_region(&dev_num, 0, 1,
				PLATFORM_DRIVER_NAME);
		if (retval < 0) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Failed to allocate char device\n");
			goto err_alloc_chrdev_region;
		}

		rmidev_major_num = MAJOR(dev_num);
	}

	device_hcd->dev_num = dev_num;

	cdev_init(&device_hcd->char_dev, &device_fops);

	retval = cdev_add(&device_hcd->char_dev, dev_num, 1);
	if (retval < 0) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to add char device\n");
		goto err_add_chardev;
	}

	retval = device_create_class();
	if (retval < 0) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to create class\n");
		goto err_create_class;
	}

	device_hcd->device = device_create(device_hcd->class, NULL,
			device_hcd->dev_num, NULL, CHAR_DEVICE_NAME"%d",
			MINOR(device_hcd->dev_num));
	if (IS_ERR(device_hcd->device)) {
		LOG_ERR(tcm_hcd->pdev->dev.parent,
				"Failed to create device\n");
		retval = -ENODEV;
		goto err_create_device;
	}

	if (bdata->irq_gpio >= 0) {
		retval = gpio_export(bdata->irq_gpio, false);
		if (retval < 0) {
			LOG_ERR(tcm_hcd->pdev->dev.parent,
					"Failed to export GPIO\n");
		} else {
			retval = gpio_export_link(&tcm_hcd->pdev->dev,
					"attn", bdata->irq_gpio);
			if (retval < 0) {
				LOG_ERR(tcm_hcd->pdev->dev.parent,
						"Failed to export GPIO link\n");
			}
		}
	}

	return 0;

err_create_device:
	class_destroy(device_hcd->class);

err_create_class:
	cdev_del(&device_hcd->char_dev);

err_add_chardev:
	unregister_chrdev_region(dev_num, 1);

err_alloc_chrdev_region:
err_register_chrdev_region:
	RELEASE_BUFFER(device_hcd->report);
	RELEASE_BUFFER(device_hcd->resp);
	RELEASE_BUFFER(device_hcd->out);

	kfree(device_hcd);
	device_hcd = NULL;

	return retval;
}

static int device_remove(struct syna_tcm_hcd *tcm_hcd)
{
	if (!device_hcd)
		goto exit;

	device_destroy(device_hcd->class, device_hcd->dev_num);

	class_destroy(device_hcd->class);

	cdev_del(&device_hcd->char_dev);

	unregister_chrdev_region(device_hcd->dev_num, 1);

	RELEASE_BUFFER(device_hcd->report);
	RELEASE_BUFFER(device_hcd->resp);
	RELEASE_BUFFER(device_hcd->out);

	kfree(device_hcd);
	device_hcd = NULL;

exit:
	complete(&device_remove_complete);

	return 0;
}

static int device_reset(struct syna_tcm_hcd *tcm_hcd)
{
	int retval;

	if (!device_hcd) {
		retval = device_init(tcm_hcd);
		return retval;
	}

	return 0;
}

static struct syna_tcm_module_cb device_module = {
	.type = TCM_DEVICE,
	.init = device_init,
	.remove = device_remove,
	.syncbox = NULL,
	.asyncbox = NULL,
	.reset = device_reset,
	.suspend = NULL,
	.resume = NULL,
	.early_suspend = NULL,
};

static int __init device_module_init(void)
{
	return syna_tcm_add_module(&device_module, true);
}

static void __exit device_module_exit(void)
{
	syna_tcm_add_module(&device_module, false);

	wait_for_completion(&device_remove_complete);
}

module_init(device_module_init);
module_exit(device_module_exit);

MODULE_AUTHOR("Synaptics, Inc.");
MODULE_DESCRIPTION("Synaptics TCM Device Module");
MODULE_LICENSE("GPL v2");