/*
 * SPU file system -- file contents
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * Author: Arnd Bergmann <arndb@de.ibm.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, 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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#undef DEBUG

#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/module.h>
#include <linux/pagemap.h>
#include <linux/poll.h>
#include <linux/ptrace.h>

#include <asm/io.h>
#include <asm/semaphore.h>
#include <asm/spu.h>
#include <asm/uaccess.h>

#include "spufs.h"


static int
spufs_mem_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;
	file->private_data = ctx;
	file->f_mapping = inode->i_mapping;
	ctx->local_store = inode->i_mapping;
	return 0;
}

static ssize_t
spufs_mem_read(struct file *file, char __user *buffer,
				size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	char *local_store;
	int ret;

	spu_acquire(ctx);

	local_store = ctx->ops->get_ls(ctx);
	ret = simple_read_from_buffer(buffer, size, pos, local_store, LS_SIZE);

	spu_release(ctx);
	return ret;
}

static ssize_t
spufs_mem_write(struct file *file, const char __user *buffer,
					size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	char *local_store;
	int ret;

	size = min_t(ssize_t, LS_SIZE - *pos, size);
	if (size <= 0)
		return -EFBIG;
	*pos += size;

	spu_acquire(ctx);

	local_store = ctx->ops->get_ls(ctx);
	ret = copy_from_user(local_store + *pos - size,
			     buffer, size) ? -EFAULT : size;

	spu_release(ctx);
	return ret;
}

#ifdef CONFIG_SPUFS_MMAP
static struct page *
spufs_mem_mmap_nopage(struct vm_area_struct *vma,
		      unsigned long address, int *type)
{
	struct page *page = NOPAGE_SIGBUS;

	struct spu_context *ctx = vma->vm_file->private_data;
	unsigned long offset = address - vma->vm_start;
	offset += vma->vm_pgoff << PAGE_SHIFT;

	spu_acquire(ctx);

	if (ctx->state == SPU_STATE_SAVED)
		page = vmalloc_to_page(ctx->csa.lscsa->ls + offset);
	else
		page = pfn_to_page((ctx->spu->local_store_phys + offset)
				   >> PAGE_SHIFT);

	spu_release(ctx);

	if (type)
		*type = VM_FAULT_MINOR;

	page_cache_get(page);
	return page;
}

static struct vm_operations_struct spufs_mem_mmap_vmops = {
	.nopage = spufs_mem_mmap_nopage,
};

static int
spufs_mem_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	/* FIXME: */
	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
				     | _PAGE_NO_CACHE);

	vma->vm_ops = &spufs_mem_mmap_vmops;
	return 0;
}
#endif

static struct file_operations spufs_mem_fops = {
	.open	 = spufs_mem_open,
	.read    = spufs_mem_read,
	.write   = spufs_mem_write,
	.llseek  = generic_file_llseek,
#ifdef CONFIG_SPUFS_MMAP
	.mmap    = spufs_mem_mmap,
#endif
};

#ifdef CONFIG_SPUFS_MMAP
static struct page *spufs_ps_nopage(struct vm_area_struct *vma,
				    unsigned long address,
				    int *type, unsigned long ps_offs)
{
	struct page *page = NOPAGE_SIGBUS;
	int fault_type = VM_FAULT_SIGBUS;
	struct spu_context *ctx = vma->vm_file->private_data;
	unsigned long offset = address - vma->vm_start;
	unsigned long area;
	int ret;

	offset += vma->vm_pgoff << PAGE_SHIFT;
	if (offset >= 0x4000)
		goto out;

	ret = spu_acquire_runnable(ctx);
	if (ret)
		goto out;

	area = ctx->spu->problem_phys + ps_offs;
	page = pfn_to_page((area + offset) >> PAGE_SHIFT);
	fault_type = VM_FAULT_MINOR;
	page_cache_get(page);

	spu_release(ctx);

      out:
	if (type)
		*type = fault_type;

	return page;
}

static struct page *spufs_cntl_mmap_nopage(struct vm_area_struct *vma,
					   unsigned long address, int *type)
{
	return spufs_ps_nopage(vma, address, type, 0x4000);
}

static struct vm_operations_struct spufs_cntl_mmap_vmops = {
	.nopage = spufs_cntl_mmap_nopage,
};

/*
 * mmap support for problem state control area [0x4000 - 0x4fff].
 * Mapping this area requires that the application have CAP_SYS_RAWIO,
 * as these registers require special care when read/writing.
 */
static int spufs_cntl_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	if (!capable(CAP_SYS_RAWIO))
		return -EPERM;

	vma->vm_flags |= VM_RESERVED;
	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
				     | _PAGE_NO_CACHE);

	vma->vm_ops = &spufs_cntl_mmap_vmops;
	return 0;
}
#endif

static int spufs_cntl_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	file->private_data = ctx;
	file->f_mapping = inode->i_mapping;
	ctx->cntl = inode->i_mapping;
	return 0;
}

static ssize_t
spufs_cntl_read(struct file *file, char __user *buffer,
		size_t size, loff_t *pos)
{
	/* FIXME: read from spu status */
	return -EINVAL;
}

static ssize_t
spufs_cntl_write(struct file *file, const char __user *buffer,
		 size_t size, loff_t *pos)
{
	/* FIXME: write to runctl bit */
	return -EINVAL;
}

static struct file_operations spufs_cntl_fops = {
	.open = spufs_cntl_open,
	.read = spufs_cntl_read,
	.write = spufs_cntl_write,
#ifdef CONFIG_SPUFS_MMAP
	.mmap = spufs_cntl_mmap,
#endif
};

static int
spufs_regs_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	file->private_data = i->i_ctx;
	return 0;
}

static ssize_t
spufs_regs_read(struct file *file, char __user *buffer,
		size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	int ret;

	spu_acquire_saved(ctx);

	ret = simple_read_from_buffer(buffer, size, pos,
				      lscsa->gprs, sizeof lscsa->gprs);

	spu_release(ctx);
	return ret;
}

static ssize_t
spufs_regs_write(struct file *file, const char __user *buffer,
		 size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	int ret;

	size = min_t(ssize_t, sizeof lscsa->gprs - *pos, size);
	if (size <= 0)
		return -EFBIG;
	*pos += size;

	spu_acquire_saved(ctx);

	ret = copy_from_user(lscsa->gprs + *pos - size,
			     buffer, size) ? -EFAULT : size;

	spu_release(ctx);
	return ret;
}

static struct file_operations spufs_regs_fops = {
	.open	 = spufs_regs_open,
	.read    = spufs_regs_read,
	.write   = spufs_regs_write,
	.llseek  = generic_file_llseek,
};

static ssize_t
spufs_fpcr_read(struct file *file, char __user * buffer,
		size_t size, loff_t * pos)
{
	struct spu_context *ctx = file->private_data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	int ret;

	spu_acquire_saved(ctx);

	ret = simple_read_from_buffer(buffer, size, pos,
				      &lscsa->fpcr, sizeof(lscsa->fpcr));

	spu_release(ctx);
	return ret;
}

static ssize_t
spufs_fpcr_write(struct file *file, const char __user * buffer,
		 size_t size, loff_t * pos)
{
	struct spu_context *ctx = file->private_data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	int ret;

	size = min_t(ssize_t, sizeof(lscsa->fpcr) - *pos, size);
	if (size <= 0)
		return -EFBIG;
	*pos += size;

	spu_acquire_saved(ctx);

	ret = copy_from_user((char *)&lscsa->fpcr + *pos - size,
			     buffer, size) ? -EFAULT : size;

	spu_release(ctx);
	return ret;
}

static struct file_operations spufs_fpcr_fops = {
	.open = spufs_regs_open,
	.read = spufs_fpcr_read,
	.write = spufs_fpcr_write,
	.llseek = generic_file_llseek,
};

/* generic open function for all pipe-like files */
static int spufs_pipe_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	file->private_data = i->i_ctx;

	return nonseekable_open(inode, file);
}

static ssize_t spufs_mbox_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 mbox_data;
	int ret;

	if (len < 4)
		return -EINVAL;

	spu_acquire(ctx);
	ret = ctx->ops->mbox_read(ctx, &mbox_data);
	spu_release(ctx);

	if (!ret)
		return -EAGAIN;

	if (copy_to_user(buf, &mbox_data, sizeof mbox_data))
		return -EFAULT;

	return 4;
}

static struct file_operations spufs_mbox_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_mbox_read,
};

static ssize_t spufs_mbox_stat_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 mbox_stat;

	if (len < 4)
		return -EINVAL;

	spu_acquire(ctx);

	mbox_stat = ctx->ops->mbox_stat_read(ctx) & 0xff;

	spu_release(ctx);

	if (copy_to_user(buf, &mbox_stat, sizeof mbox_stat))
		return -EFAULT;

	return 4;
}

static struct file_operations spufs_mbox_stat_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_mbox_stat_read,
};

/* low-level ibox access function */
size_t spu_ibox_read(struct spu_context *ctx, u32 *data)
{
	return ctx->ops->ibox_read(ctx, data);
}

static int spufs_ibox_fasync(int fd, struct file *file, int on)
{
	struct spu_context *ctx = file->private_data;

	return fasync_helper(fd, file, on, &ctx->ibox_fasync);
}

/* interrupt-level ibox callback function. */
void spufs_ibox_callback(struct spu *spu)
{
	struct spu_context *ctx = spu->ctx;

	wake_up_all(&ctx->ibox_wq);
	kill_fasync(&ctx->ibox_fasync, SIGIO, POLLIN);
}

static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 ibox_data;
	ssize_t ret;

	if (len < 4)
		return -EINVAL;

	spu_acquire(ctx);

	ret = 0;
	if (file->f_flags & O_NONBLOCK) {
		if (!spu_ibox_read(ctx, &ibox_data))
			ret = -EAGAIN;
	} else {
		ret = spufs_wait(ctx->ibox_wq, spu_ibox_read(ctx, &ibox_data));
	}

	spu_release(ctx);

	if (ret)
		return ret;

	ret = 4;
	if (copy_to_user(buf, &ibox_data, sizeof ibox_data))
		ret = -EFAULT;

	return ret;
}

static unsigned int spufs_ibox_poll(struct file *file, poll_table *wait)
{
	struct spu_context *ctx = file->private_data;
	unsigned int mask;

	poll_wait(file, &ctx->ibox_wq, wait);

	spu_acquire(ctx);
	mask = ctx->ops->mbox_stat_poll(ctx, POLLIN | POLLRDNORM);
	spu_release(ctx);

	return mask;
}

static struct file_operations spufs_ibox_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_ibox_read,
	.poll	= spufs_ibox_poll,
	.fasync	= spufs_ibox_fasync,
};

static ssize_t spufs_ibox_stat_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 ibox_stat;

	if (len < 4)
		return -EINVAL;

	spu_acquire(ctx);
	ibox_stat = (ctx->ops->mbox_stat_read(ctx) >> 16) & 0xff;
	spu_release(ctx);

	if (copy_to_user(buf, &ibox_stat, sizeof ibox_stat))
		return -EFAULT;

	return 4;
}

static struct file_operations spufs_ibox_stat_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_ibox_stat_read,
};

/* low-level mailbox write */
size_t spu_wbox_write(struct spu_context *ctx, u32 data)
{
	return ctx->ops->wbox_write(ctx, data);
}

static int spufs_wbox_fasync(int fd, struct file *file, int on)
{
	struct spu_context *ctx = file->private_data;
	int ret;

	ret = fasync_helper(fd, file, on, &ctx->wbox_fasync);

	return ret;
}

/* interrupt-level wbox callback function. */
void spufs_wbox_callback(struct spu *spu)
{
	struct spu_context *ctx = spu->ctx;

	wake_up_all(&ctx->wbox_wq);
	kill_fasync(&ctx->wbox_fasync, SIGIO, POLLOUT);
}

static ssize_t spufs_wbox_write(struct file *file, const char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 wbox_data;
	int ret;

	if (len < 4)
		return -EINVAL;

	if (copy_from_user(&wbox_data, buf, sizeof wbox_data))
		return -EFAULT;

	spu_acquire(ctx);

	ret = 0;
	if (file->f_flags & O_NONBLOCK) {
		if (!spu_wbox_write(ctx, wbox_data))
			ret = -EAGAIN;
	} else {
		ret = spufs_wait(ctx->wbox_wq, spu_wbox_write(ctx, wbox_data));
	}

	spu_release(ctx);

	return ret ? ret : sizeof wbox_data;
}

static unsigned int spufs_wbox_poll(struct file *file, poll_table *wait)
{
	struct spu_context *ctx = file->private_data;
	unsigned int mask;

	poll_wait(file, &ctx->wbox_wq, wait);

	spu_acquire(ctx);
	mask = ctx->ops->mbox_stat_poll(ctx, POLLOUT | POLLWRNORM);
	spu_release(ctx);

	return mask;
}

static struct file_operations spufs_wbox_fops = {
	.open	= spufs_pipe_open,
	.write	= spufs_wbox_write,
	.poll	= spufs_wbox_poll,
	.fasync	= spufs_wbox_fasync,
};

static ssize_t spufs_wbox_stat_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 wbox_stat;

	if (len < 4)
		return -EINVAL;

	spu_acquire(ctx);
	wbox_stat = (ctx->ops->mbox_stat_read(ctx) >> 8) & 0xff;
	spu_release(ctx);

	if (copy_to_user(buf, &wbox_stat, sizeof wbox_stat))
		return -EFAULT;

	return 4;
}

static struct file_operations spufs_wbox_stat_fops = {
	.open	= spufs_pipe_open,
	.read	= spufs_wbox_stat_read,
};

static int spufs_signal1_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;
	file->private_data = ctx;
	file->f_mapping = inode->i_mapping;
	ctx->signal1 = inode->i_mapping;
	return nonseekable_open(inode, file);
}

static ssize_t spufs_signal1_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	u32 data;

	if (len < 4)
		return -EINVAL;

	spu_acquire(ctx);
	data = ctx->ops->signal1_read(ctx);
	spu_release(ctx);

	if (copy_to_user(buf, &data, 4))
		return -EFAULT;

	return 4;
}

static ssize_t spufs_signal1_write(struct file *file, const char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx;
	u32 data;

	ctx = file->private_data;

	if (len < 4)
		return -EINVAL;

	if (copy_from_user(&data, buf, 4))
		return -EFAULT;

	spu_acquire(ctx);
	ctx->ops->signal1_write(ctx, data);
	spu_release(ctx);

	return 4;
}

#ifdef CONFIG_SPUFS_MMAP
static struct page *spufs_signal1_mmap_nopage(struct vm_area_struct *vma,
					      unsigned long address, int *type)
{
	return spufs_ps_nopage(vma, address, type, 0x14000);
}

static struct vm_operations_struct spufs_signal1_mmap_vmops = {
	.nopage = spufs_signal1_mmap_nopage,
};

static int spufs_signal1_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	vma->vm_flags |= VM_RESERVED;
	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
				     | _PAGE_NO_CACHE);

	vma->vm_ops = &spufs_signal1_mmap_vmops;
	return 0;
}
#endif

static struct file_operations spufs_signal1_fops = {
	.open = spufs_signal1_open,
	.read = spufs_signal1_read,
	.write = spufs_signal1_write,
#ifdef CONFIG_SPUFS_MMAP
	.mmap = spufs_signal1_mmap,
#endif
};

static int spufs_signal2_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;
	file->private_data = ctx;
	file->f_mapping = inode->i_mapping;
	ctx->signal2 = inode->i_mapping;
	return nonseekable_open(inode, file);
}

static ssize_t spufs_signal2_read(struct file *file, char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx;
	u32 data;

	ctx = file->private_data;

	if (len < 4)
		return -EINVAL;

	spu_acquire(ctx);
	data = ctx->ops->signal2_read(ctx);
	spu_release(ctx);

	if (copy_to_user(buf, &data, 4))
		return -EFAULT;

	return 4;
}

static ssize_t spufs_signal2_write(struct file *file, const char __user *buf,
			size_t len, loff_t *pos)
{
	struct spu_context *ctx;
	u32 data;

	ctx = file->private_data;

	if (len < 4)
		return -EINVAL;

	if (copy_from_user(&data, buf, 4))
		return -EFAULT;

	spu_acquire(ctx);
	ctx->ops->signal2_write(ctx, data);
	spu_release(ctx);

	return 4;
}

#ifdef CONFIG_SPUFS_MMAP
static struct page *spufs_signal2_mmap_nopage(struct vm_area_struct *vma,
					      unsigned long address, int *type)
{
	return spufs_ps_nopage(vma, address, type, 0x1c000);
}

static struct vm_operations_struct spufs_signal2_mmap_vmops = {
	.nopage = spufs_signal2_mmap_nopage,
};

static int spufs_signal2_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	/* FIXME: */
	vma->vm_flags |= VM_RESERVED;
	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
				     | _PAGE_NO_CACHE);

	vma->vm_ops = &spufs_signal2_mmap_vmops;
	return 0;
}
#endif

static struct file_operations spufs_signal2_fops = {
	.open = spufs_signal2_open,
	.read = spufs_signal2_read,
	.write = spufs_signal2_write,
#ifdef CONFIG_SPUFS_MMAP
	.mmap = spufs_signal2_mmap,
#endif
};

static void spufs_signal1_type_set(void *data, u64 val)
{
	struct spu_context *ctx = data;

	spu_acquire(ctx);
	ctx->ops->signal1_type_set(ctx, val);
	spu_release(ctx);
}

static u64 spufs_signal1_type_get(void *data)
{
	struct spu_context *ctx = data;
	u64 ret;

	spu_acquire(ctx);
	ret = ctx->ops->signal1_type_get(ctx);
	spu_release(ctx);

	return ret;
}
DEFINE_SIMPLE_ATTRIBUTE(spufs_signal1_type, spufs_signal1_type_get,
					spufs_signal1_type_set, "%llu");

static void spufs_signal2_type_set(void *data, u64 val)
{
	struct spu_context *ctx = data;

	spu_acquire(ctx);
	ctx->ops->signal2_type_set(ctx, val);
	spu_release(ctx);
}

static u64 spufs_signal2_type_get(void *data)
{
	struct spu_context *ctx = data;
	u64 ret;

	spu_acquire(ctx);
	ret = ctx->ops->signal2_type_get(ctx);
	spu_release(ctx);

	return ret;
}
DEFINE_SIMPLE_ATTRIBUTE(spufs_signal2_type, spufs_signal2_type_get,
					spufs_signal2_type_set, "%llu");

#ifdef CONFIG_SPUFS_MMAP
static struct page *spufs_mss_mmap_nopage(struct vm_area_struct *vma,
					   unsigned long address, int *type)
{
	return spufs_ps_nopage(vma, address, type, 0x0000);
}

static struct vm_operations_struct spufs_mss_mmap_vmops = {
	.nopage = spufs_mss_mmap_nopage,
};

/*
 * mmap support for problem state MFC DMA area [0x0000 - 0x0fff].
 * Mapping this area requires that the application have CAP_SYS_RAWIO,
 * as these registers require special care when read/writing.
 */
static int spufs_mss_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	if (!capable(CAP_SYS_RAWIO))
		return -EPERM;

	vma->vm_flags |= VM_RESERVED;
	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
				     | _PAGE_NO_CACHE);

	vma->vm_ops = &spufs_mss_mmap_vmops;
	return 0;
}
#endif

static int spufs_mss_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);

	file->private_data = i->i_ctx;
	return nonseekable_open(inode, file);
}

static struct file_operations spufs_mss_fops = {
	.open	 = spufs_mss_open,
#ifdef CONFIG_SPUFS_MMAP
	.mmap	 = spufs_mss_mmap,
#endif
};


#ifdef CONFIG_SPUFS_MMAP
static struct page *spufs_mfc_mmap_nopage(struct vm_area_struct *vma,
					   unsigned long address, int *type)
{
	return spufs_ps_nopage(vma, address, type, 0x3000);
}

static struct vm_operations_struct spufs_mfc_mmap_vmops = {
	.nopage = spufs_mfc_mmap_nopage,
};

/*
 * mmap support for problem state MFC DMA area [0x0000 - 0x0fff].
 * Mapping this area requires that the application have CAP_SYS_RAWIO,
 * as these registers require special care when read/writing.
 */
static int spufs_mfc_mmap(struct file *file, struct vm_area_struct *vma)
{
	if (!(vma->vm_flags & VM_SHARED))
		return -EINVAL;

	if (!capable(CAP_SYS_RAWIO))
		return -EPERM;

	vma->vm_flags |= VM_RESERVED;
	vma->vm_page_prot = __pgprot(pgprot_val(vma->vm_page_prot)
				     | _PAGE_NO_CACHE);

	vma->vm_ops = &spufs_mfc_mmap_vmops;
	return 0;
}
#endif

static int spufs_mfc_open(struct inode *inode, struct file *file)
{
	struct spufs_inode_info *i = SPUFS_I(inode);
	struct spu_context *ctx = i->i_ctx;

	/* we don't want to deal with DMA into other processes */
	if (ctx->owner != current->mm)
		return -EINVAL;

	if (atomic_read(&inode->i_count) != 1)
		return -EBUSY;

	file->private_data = ctx;
	return nonseekable_open(inode, file);
}

/* interrupt-level mfc callback function. */
void spufs_mfc_callback(struct spu *spu)
{
	struct spu_context *ctx = spu->ctx;

	wake_up_all(&ctx->mfc_wq);

	pr_debug("%s %s\n", __FUNCTION__, spu->name);
	if (ctx->mfc_fasync) {
		u32 free_elements, tagstatus;
		unsigned int mask;

		/* no need for spu_acquire in interrupt context */
		free_elements = ctx->ops->get_mfc_free_elements(ctx);
		tagstatus = ctx->ops->read_mfc_tagstatus(ctx);

		mask = 0;
		if (free_elements & 0xffff)
			mask |= POLLOUT;
		if (tagstatus & ctx->tagwait)
			mask |= POLLIN;

		kill_fasync(&ctx->mfc_fasync, SIGIO, mask);
	}
}

static int spufs_read_mfc_tagstatus(struct spu_context *ctx, u32 *status)
{
	/* See if there is one tag group is complete */
	/* FIXME we need locking around tagwait */
	*status = ctx->ops->read_mfc_tagstatus(ctx) & ctx->tagwait;
	ctx->tagwait &= ~*status;
	if (*status)
		return 1;

	/* enable interrupt waiting for any tag group,
	   may silently fail if interrupts are already enabled */
	ctx->ops->set_mfc_query(ctx, ctx->tagwait, 1);
	return 0;
}

static ssize_t spufs_mfc_read(struct file *file, char __user *buffer,
			size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	int ret = -EINVAL;
	u32 status;

	if (size != 4)
		goto out;

	spu_acquire(ctx);
	if (file->f_flags & O_NONBLOCK) {
		status = ctx->ops->read_mfc_tagstatus(ctx);
		if (!(status & ctx->tagwait))
			ret = -EAGAIN;
		else
			ctx->tagwait &= ~status;
	} else {
		ret = spufs_wait(ctx->mfc_wq,
			   spufs_read_mfc_tagstatus(ctx, &status));
	}
	spu_release(ctx);

	if (ret)
		goto out;

	ret = 4;
	if (copy_to_user(buffer, &status, 4))
		ret = -EFAULT;

out:
	return ret;
}

static int spufs_check_valid_dma(struct mfc_dma_command *cmd)
{
	pr_debug("queueing DMA %x %lx %x %x %x\n", cmd->lsa,
		 cmd->ea, cmd->size, cmd->tag, cmd->cmd);

	switch (cmd->cmd) {
	case MFC_PUT_CMD:
	case MFC_PUTF_CMD:
	case MFC_PUTB_CMD:
	case MFC_GET_CMD:
	case MFC_GETF_CMD:
	case MFC_GETB_CMD:
		break;
	default:
		pr_debug("invalid DMA opcode %x\n", cmd->cmd);
		return -EIO;
	}

	if ((cmd->lsa & 0xf) != (cmd->ea &0xf)) {
		pr_debug("invalid DMA alignment, ea %lx lsa %x\n",
				cmd->ea, cmd->lsa);
		return -EIO;
	}

	switch (cmd->size & 0xf) {
	case 1:
		break;
	case 2:
		if (cmd->lsa & 1)
			goto error;
		break;
	case 4:
		if (cmd->lsa & 3)
			goto error;
		break;
	case 8:
		if (cmd->lsa & 7)
			goto error;
		break;
	case 0:
		if (cmd->lsa & 15)
			goto error;
		break;
	error:
	default:
		pr_debug("invalid DMA alignment %x for size %x\n",
			cmd->lsa & 0xf, cmd->size);
		return -EIO;
	}

	if (cmd->size > 16 * 1024) {
		pr_debug("invalid DMA size %x\n", cmd->size);
		return -EIO;
	}

	if (cmd->tag & 0xfff0) {
		/* we reserve the higher tag numbers for kernel use */
		pr_debug("invalid DMA tag\n");
		return -EIO;
	}

	if (cmd->class) {
		/* not supported in this version */
		pr_debug("invalid DMA class\n");
		return -EIO;
	}

	return 0;
}

static int spu_send_mfc_command(struct spu_context *ctx,
				struct mfc_dma_command cmd,
				int *error)
{
	*error = ctx->ops->send_mfc_command(ctx, &cmd);
	if (*error == -EAGAIN) {
		/* wait for any tag group to complete
		   so we have space for the new command */
		ctx->ops->set_mfc_query(ctx, ctx->tagwait, 1);
		/* try again, because the queue might be
		   empty again */
		*error = ctx->ops->send_mfc_command(ctx, &cmd);
		if (*error == -EAGAIN)
			return 0;
	}
	return 1;
}

static ssize_t spufs_mfc_write(struct file *file, const char __user *buffer,
			size_t size, loff_t *pos)
{
	struct spu_context *ctx = file->private_data;
	struct mfc_dma_command cmd;
	int ret = -EINVAL;

	if (size != sizeof cmd)
		goto out;

	ret = -EFAULT;
	if (copy_from_user(&cmd, buffer, sizeof cmd))
		goto out;

	ret = spufs_check_valid_dma(&cmd);
	if (ret)
		goto out;

	spu_acquire_runnable(ctx);
	if (file->f_flags & O_NONBLOCK) {
		ret = ctx->ops->send_mfc_command(ctx, &cmd);
	} else {
		int status;
		ret = spufs_wait(ctx->mfc_wq,
				 spu_send_mfc_command(ctx, cmd, &status));
		if (status)
			ret = status;
	}
	spu_release(ctx);

	if (ret)
		goto out;

	ctx->tagwait |= 1 << cmd.tag;

out:
	return ret;
}

static unsigned int spufs_mfc_poll(struct file *file,poll_table *wait)
{
	struct spu_context *ctx = file->private_data;
	u32 free_elements, tagstatus;
	unsigned int mask;

	spu_acquire(ctx);
	ctx->ops->set_mfc_query(ctx, ctx->tagwait, 2);
	free_elements = ctx->ops->get_mfc_free_elements(ctx);
	tagstatus = ctx->ops->read_mfc_tagstatus(ctx);
	spu_release(ctx);

	poll_wait(file, &ctx->mfc_wq, wait);

	mask = 0;
	if (free_elements & 0xffff)
		mask |= POLLOUT | POLLWRNORM;
	if (tagstatus & ctx->tagwait)
		mask |= POLLIN | POLLRDNORM;

	pr_debug("%s: free %d tagstatus %d tagwait %d\n", __FUNCTION__,
		free_elements, tagstatus, ctx->tagwait);

	return mask;
}

static int spufs_mfc_flush(struct file *file, fl_owner_t id)
{
	struct spu_context *ctx = file->private_data;
	int ret;

	spu_acquire(ctx);
#if 0
/* this currently hangs */
	ret = spufs_wait(ctx->mfc_wq,
			 ctx->ops->set_mfc_query(ctx, ctx->tagwait, 2));
	if (ret)
		goto out;
	ret = spufs_wait(ctx->mfc_wq,
			 ctx->ops->read_mfc_tagstatus(ctx) == ctx->tagwait);
out:
#else
	ret = 0;
#endif
	spu_release(ctx);

	return ret;
}

static int spufs_mfc_fsync(struct file *file, struct dentry *dentry,
			   int datasync)
{
	return spufs_mfc_flush(file, NULL);
}

static int spufs_mfc_fasync(int fd, struct file *file, int on)
{
	struct spu_context *ctx = file->private_data;

	return fasync_helper(fd, file, on, &ctx->mfc_fasync);
}

static struct file_operations spufs_mfc_fops = {
	.open	 = spufs_mfc_open,
	.read	 = spufs_mfc_read,
	.write	 = spufs_mfc_write,
	.poll	 = spufs_mfc_poll,
	.flush	 = spufs_mfc_flush,
	.fsync	 = spufs_mfc_fsync,
	.fasync	 = spufs_mfc_fasync,
#ifdef CONFIG_SPUFS_MMAP
	.mmap	 = spufs_mfc_mmap,
#endif
};

static void spufs_npc_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	spu_acquire(ctx);
	ctx->ops->npc_write(ctx, val);
	spu_release(ctx);
}

static u64 spufs_npc_get(void *data)
{
	struct spu_context *ctx = data;
	u64 ret;
	spu_acquire(ctx);
	ret = ctx->ops->npc_read(ctx);
	spu_release(ctx);
	return ret;
}
DEFINE_SIMPLE_ATTRIBUTE(spufs_npc_ops, spufs_npc_get, spufs_npc_set, "%llx\n")

static void spufs_decr_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	spu_acquire_saved(ctx);
	lscsa->decr.slot[0] = (u32) val;
	spu_release(ctx);
}

static u64 spufs_decr_get(void *data)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	u64 ret;
	spu_acquire_saved(ctx);
	ret = lscsa->decr.slot[0];
	spu_release(ctx);
	return ret;
}
DEFINE_SIMPLE_ATTRIBUTE(spufs_decr_ops, spufs_decr_get, spufs_decr_set,
			"%llx\n")

static void spufs_decr_status_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	spu_acquire_saved(ctx);
	lscsa->decr_status.slot[0] = (u32) val;
	spu_release(ctx);
}

static u64 spufs_decr_status_get(void *data)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	u64 ret;
	spu_acquire_saved(ctx);
	ret = lscsa->decr_status.slot[0];
	spu_release(ctx);
	return ret;
}
DEFINE_SIMPLE_ATTRIBUTE(spufs_decr_status_ops, spufs_decr_status_get,
			spufs_decr_status_set, "%llx\n")

static void spufs_spu_tag_mask_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	spu_acquire_saved(ctx);
	lscsa->tag_mask.slot[0] = (u32) val;
	spu_release(ctx);
}

static u64 spufs_spu_tag_mask_get(void *data)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	u64 ret;
	spu_acquire_saved(ctx);
	ret = lscsa->tag_mask.slot[0];
	spu_release(ctx);
	return ret;
}
DEFINE_SIMPLE_ATTRIBUTE(spufs_spu_tag_mask_ops, spufs_spu_tag_mask_get,
			spufs_spu_tag_mask_set, "%llx\n")

static void spufs_event_mask_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	spu_acquire_saved(ctx);
	lscsa->event_mask.slot[0] = (u32) val;
	spu_release(ctx);
}

static u64 spufs_event_mask_get(void *data)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	u64 ret;
	spu_acquire_saved(ctx);
	ret = lscsa->event_mask.slot[0];
	spu_release(ctx);
	return ret;
}
DEFINE_SIMPLE_ATTRIBUTE(spufs_event_mask_ops, spufs_event_mask_get,
			spufs_event_mask_set, "%llx\n")

static void spufs_srr0_set(void *data, u64 val)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	spu_acquire_saved(ctx);
	lscsa->srr0.slot[0] = (u32) val;
	spu_release(ctx);
}

static u64 spufs_srr0_get(void *data)
{
	struct spu_context *ctx = data;
	struct spu_lscsa *lscsa = ctx->csa.lscsa;
	u64 ret;
	spu_acquire_saved(ctx);
	ret = lscsa->srr0.slot[0];
	spu_release(ctx);
	return ret;
}
DEFINE_SIMPLE_ATTRIBUTE(spufs_srr0_ops, spufs_srr0_get, spufs_srr0_set,
			"%llx\n")

static u64 spufs_id_get(void *data)
{
	struct spu_context *ctx = data;
	u64 num;

	spu_acquire(ctx);
	if (ctx->state == SPU_STATE_RUNNABLE)
		num = ctx->spu->number;
	else
		num = (unsigned int)-1;
	spu_release(ctx);

	return num;
}
DEFINE_SIMPLE_ATTRIBUTE(spufs_id_ops, spufs_id_get, 0, "0x%llx\n")

struct tree_descr spufs_dir_contents[] = {
	{ "mem",  &spufs_mem_fops,  0666, },
	{ "regs", &spufs_regs_fops,  0666, },
	{ "mbox", &spufs_mbox_fops, 0444, },
	{ "ibox", &spufs_ibox_fops, 0444, },
	{ "wbox", &spufs_wbox_fops, 0222, },
	{ "mbox_stat", &spufs_mbox_stat_fops, 0444, },
	{ "ibox_stat", &spufs_ibox_stat_fops, 0444, },
	{ "wbox_stat", &spufs_wbox_stat_fops, 0444, },
	{ "signal1", &spufs_signal1_fops, 0666, },
	{ "signal2", &spufs_signal2_fops, 0666, },
	{ "signal1_type", &spufs_signal1_type, 0666, },
	{ "signal2_type", &spufs_signal2_type, 0666, },
	{ "mss", &spufs_mss_fops, 0666, },
	{ "mfc", &spufs_mfc_fops, 0666, },
	{ "cntl", &spufs_cntl_fops,  0666, },
	{ "npc", &spufs_npc_ops, 0666, },
	{ "fpcr", &spufs_fpcr_fops, 0666, },
	{ "decr", &spufs_decr_ops, 0666, },
	{ "decr_status", &spufs_decr_status_ops, 0666, },
	{ "spu_tag_mask", &spufs_spu_tag_mask_ops, 0666, },
	{ "event_mask", &spufs_event_mask_ops, 0666, },
	{ "srr0", &spufs_srr0_ops, 0666, },
	{ "phys-id", &spufs_id_ops, 0666, },
	{},
};