/* arch/arm/mach-msm/hw3d.c
 *
 * Register/Interrupt access for userspace 3D library.
 *
 * Copyright (C) 2007 Google, Inc.
 * Author: Brian Swetland <swetland@google.com>
 *
 * This software is licensed under the terms of the GNU General Public
 * License version 2, as published by the Free Software Foundation, and
 * may be copied, distributed, and modified under those terms.
 *
 * 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.
 *
 */

#include <linux/module.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/uaccess.h>
#include <linux/poll.h>
#include <linux/time.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/mm.h>
#include <linux/clk.h>
#include <linux/android_pmem.h>
#include <mach/board.h>

static DEFINE_SPINLOCK(hw3d_lock);
static DECLARE_WAIT_QUEUE_HEAD(hw3d_queue);
static int hw3d_pending;
static int hw3d_disabled;

static struct clk *grp_clk;
static struct clk *imem_clk;
DECLARE_MUTEX(hw3d_sem);
static unsigned int hw3d_granted;
static struct file *hw3d_granted_file;

static irqreturn_t hw3d_irq_handler(int irq, void *data)
{
	unsigned long flags;

	spin_lock_irqsave(&hw3d_lock, flags);
	if (!hw3d_disabled) {
		disable_irq(INT_GRAPHICS);
		hw3d_disabled = 1;
	}
	hw3d_pending = 1;
	spin_unlock_irqrestore(&hw3d_lock, flags);

	wake_up(&hw3d_queue);

	return IRQ_HANDLED;
}

static void hw3d_disable_interrupt(void)
{
	unsigned long flags;
	spin_lock_irqsave(&hw3d_lock, flags);
	if (!hw3d_disabled) {
		disable_irq(INT_GRAPHICS);
		hw3d_disabled = 1;
	}
	spin_unlock_irqrestore(&hw3d_lock, flags);
}

static long hw3d_wait_for_interrupt(void)
{
	unsigned long flags;
	int ret;

	for (;;) {
		spin_lock_irqsave(&hw3d_lock, flags);
		if (hw3d_pending) {
			hw3d_pending = 0;
			spin_unlock_irqrestore(&hw3d_lock, flags);
			return 0;
		}
		if (hw3d_disabled) {
			hw3d_disabled = 0;
			enable_irq(INT_GRAPHICS);
		}
		spin_unlock_irqrestore(&hw3d_lock, flags);

		ret = wait_event_interruptible(hw3d_queue, hw3d_pending);
		if (ret < 0) {
			hw3d_disable_interrupt();
			return ret;
		}
	}

	return 0;
}

#define HW3D_REGS_LEN 0x100000
static long hw3d_wait_for_revoke(struct hw3d_info *info, struct file *filp)
{
	struct hw3d_data *data = filp->private_data;
	int ret;

	if (is_master(info, filp)) {
		pr_err("%s: cannot revoke on master node\n", __func__);
		return -EPERM;
	}

	ret = wait_event_interruptible(info->revoke_wq,
				       info->revoking ||
				       data->closing);
	if (ret == 0 && data->closing)
		ret = -EPIPE;
	if (ret < 0)
		return ret;
	return 0;
}

static void locked_hw3d_client_done(struct hw3d_info *info, int had_timer)
{
	if (info->enabled) {
		pr_debug("hw3d: was enabled\n");
		info->enabled = 0;
		clk_disable(info->grp_clk);
		clk_disable(info->imem_clk);
	}
	info->revoking = 0;

	/* double check that the irqs are disabled */
	locked_hw3d_irq_disable(info);

	if (had_timer)
		wake_unlock(&info->wake_lock);
	wake_up(&info->revoke_done_wq);
}

static void do_force_revoke(struct hw3d_info *info)
{
	unsigned long flags;

	/* at this point, the task had a chance to relinquish the gpu, but
	 * it hasn't. So, we kill it */
	spin_lock_irqsave(&info->lock, flags);
	pr_debug("hw3d: forcing revoke\n");
	locked_hw3d_irq_disable(info);
	if (info->client_task) {
		pr_info("hw3d: force revoke from pid=%d\n",
			info->client_task->pid);
		force_sig(SIGKILL, info->client_task);
		put_task_struct(info->client_task);
		info->client_task = NULL;
	}
	locked_hw3d_client_done(info, 1);
	pr_debug("hw3d: done forcing revoke\n");
	spin_unlock_irqrestore(&info->lock, flags);
}

#define REVOKE_TIMEOUT		(2 * HZ)
static void locked_hw3d_revoke(struct hw3d_info *info)
{
	/* force us to wait to suspend until the revoke is done. If the
	 * user doesn't release the gpu, the timer will turn off the gpu,
	 * and force kill the process. */
	wake_lock(&info->wake_lock);
	info->revoking = 1;
	wake_up(&info->revoke_wq);
	mod_timer(&info->revoke_timer, jiffies + REVOKE_TIMEOUT);
}

bool is_msm_hw3d_file(struct file *file)
{
	struct hw3d_info *info = hw3d_info;
	if (MAJOR(file->f_dentry->d_inode->i_rdev) == MAJOR(info->devno) &&
	    (is_master(info, file) || is_client(info, file)))
		return 1;
	return 0;
}

void put_msm_hw3d_file(struct file *file)
{
	if (!is_msm_hw3d_file(file))
		return;
	fput(file);
}

static long hw3d_revoke_gpu(struct file *file)
{
	int ret = 0;
	unsigned long user_start, user_len;
	struct pmem_region region = {.offset = 0x0, .len = HW3D_REGS_LEN};

	down(&hw3d_sem);
	if (!hw3d_granted)
		goto end;
	/* revoke the pmem region completely */
	if ((ret = pmem_remap(&region, file, PMEM_UNMAP)))
		goto end;
	get_pmem_user_addr(file, &user_start, &user_len);
	/* reset the gpu */
	clk_disable(grp_clk);
	clk_disable(imem_clk);
	hw3d_granted = 0;
end:
	up(&hw3d_sem);
	return ret;
}

static long hw3d_grant_gpu(struct file *file)
{
	int ret = 0;
	struct pmem_region region = {.offset = 0x0, .len = HW3D_REGS_LEN};

	down(&hw3d_sem);
	if (hw3d_granted) {
		ret = -1;
		goto end;
	}
	/* map the registers */
	if ((ret = pmem_remap(&region, file, PMEM_MAP)))
		goto end;
	clk_enable(grp_clk);
	clk_enable(imem_clk);
	hw3d_granted = 1;
	hw3d_granted_file = file;
end:
	up(&hw3d_sem);
	return ret;
}

static int hw3d_release(struct inode *inode, struct file *file)
{
	down(&hw3d_sem);
	/* if the gpu is in use, and its inuse by the file that was released */
	if (hw3d_granted && (file == hw3d_granted_file)) {
		clk_disable(grp_clk);
		clk_disable(imem_clk);
		hw3d_granted = 0;
		hw3d_granted_file = NULL;
	}
	up(&hw3d_sem);
	return 0;
}

static void hw3d_vma_open(struct vm_area_struct *vma)
{
	/* XXX: should the master be allowed to fork and keep the mappings? */

	/* TODO: remap garbage page into here.
	 *
	 * For now, just pull the mapping. The user shouldn't be forking
	 * and using it anyway. */
	zap_page_range(vma, vma->vm_start, vma->vm_end - vma->vm_start, NULL);
}

static void hw3d_vma_close(struct vm_area_struct *vma)
{
	struct file *file = vma->vm_file;
	struct hw3d_data *data = file->private_data;
	int i;

	pr_debug("hw3d: current %u ppid %u file %p count %ld\n",
		 current->pid, current->parent->pid, file, file_count(file));

	BUG_ON(!data);

	mutex_lock(&data->mutex);
	for (i = 0; i < HW3D_NUM_REGIONS; ++i) {
		if (data->vmas[i] == vma) {
			data->vmas[i] = NULL;
			goto done;
		}
	}
	pr_warning("%s: vma %p not of ours during vma_close\n", __func__, vma);
done:
	mutex_unlock(&data->mutex);
}

static int hw3d_mmap(struct file *file, struct vm_area_struct *vma)
{
	struct hw3d_info *info = hw3d_info;
	struct hw3d_data *data = file->private_data;
	unsigned long vma_size = vma->vm_end - vma->vm_start;
	int ret = 0;
	int region = REGION_PAGE_ID(vma->vm_pgoff);

	if (region >= HW3D_NUM_REGIONS) {
		pr_err("%s: Trying to mmap unknown region %d\n", __func__,
		       region);
		return -EINVAL;
	} else if (vma_size > info->regions[region].size) {
		pr_err("%s: VMA size %ld exceeds region %d size %ld\n",
			__func__, vma_size, region,
			info->regions[region].size);
		return -EINVAL;
	} else if (REGION_PAGE_OFFS(vma->vm_pgoff) != 0 ||
		   (vma_size & ~PAGE_MASK)) {
		pr_err("%s: Can't remap part of the region %d\n", __func__,
		       region);
		return -EINVAL;
	} else if (!is_master(info, file) &&
		   current->group_leader != info->client_task) {
		pr_err("%s: current(%d) != client_task(%d)\n", __func__,
		       current->group_leader->pid, info->client_task->pid);
		return -EPERM;
	} else if (!is_master(info, file) &&
		   (info->revoking || info->suspending)) {
		pr_err("%s: cannot mmap while revoking(%d) or suspending(%d)\n",
		       __func__, info->revoking, info->suspending);
		return -EPERM;
	}

	mutex_lock(&data->mutex);
	if (data->vmas[region] != NULL) {
		pr_err("%s: Region %d already mapped (pid=%d tid=%d)\n",
		       __func__, region, current->group_leader->pid,
		       current->pid);
		ret = -EBUSY;
		goto done;
	}

	/* our mappings are always noncached */
#ifdef pgprot_noncached
	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
#endif

	ret = io_remap_pfn_range(vma, vma->vm_start,
				 info->regions[region].pbase >> PAGE_SHIFT,
				 vma_size, vma->vm_page_prot);
	if (ret) {
		pr_err("%s: Cannot remap page range for region %d!\n", __func__,
		       region);
		ret = -EAGAIN;
		goto done;
	}

	/* Prevent a malicious client from stealing another client's data
	 * by forcing a revoke on it and then mmapping the GPU buffers.
	 */
	if (region != HW3D_REGS)
		memset(info->regions[region].vbase, 0,
		       info->regions[region].size);

	vma->vm_ops = &hw3d_vm_ops;

	/* mark this region as mapped */
	data->vmas[region] = vma;

done:
	mutex_unlock(&data->mutex);
	return ret;
}

static long hw3d_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
{
	switch (cmd) {
		case HW3D_REVOKE_GPU:
			return hw3d_revoke_gpu(file);
			break;
		case HW3D_GRANT_GPU:
			return hw3d_grant_gpu(file);
			break;
		case HW3D_WAIT_FOR_INTERRUPT:
			return hw3d_wait_for_interrupt();
			break;
		default:
			return -EINVAL;
	}
	return 0;
}

static struct android_pmem_platform_data pmem_data = {
	.name = "hw3d",
	.start = 0xA0000000,
	.size = 0x100000,
	.allocator_type = PMEM_ALLOCATORTYPE_ALLORNOTHING,
	.cached = 0,
};

static int __init hw3d_init(void)
{
	int ret;

	grp_clk = clk_get(NULL, "grp_clk");
	if (IS_ERR(grp_clk))
		return PTR_ERR(grp_clk);
	
	imem_clk = clk_get(NULL, "imem_clk");
	if (IS_ERR(imem_clk)) {
		clk_put(grp_clk);
		return PTR_ERR(imem_clk);
	}
	ret = request_irq(INT_GRAPHICS, hw3d_irq_handler,
			  IRQF_TRIGGER_HIGH, "hw3d", 0);
	if (ret) {
		clk_put(grp_clk);
		clk_put(imem_clk);
		return ret;
	}
	hw3d_disable_interrupt();
	hw3d_granted = 0;

	return pmem_setup(&pmem_data, hw3d_ioctl, hw3d_release);
}

device_initcall(hw3d_init);