Staging: poch: Remove circular buffer header

Remove the circular buffer header. Which has been superseded by the
ioctl consume interface.
Signed-off-by: Vijay Kumar B <vijaykumar@bravegnu.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/poch/README

 TODO:
 	- Rx block size is limited to < 2048, hardware bug?
 	- Group size is limited to < page size, kernel alloc/mmap API issues
-	- fix/workaround cache issues in circular buffer header
 	- test whether Tx is transmitting data from provided buffers
 	- handle device unplug case
 	- handle temperature above threshold

drivers/staging/poch/poch.c

@@ -197,9 +197,6 @@ struct channel_info {
 
 	/* Contains the header and circular buffer exported to userspace. */
 	spinlock_t group_offsets_lock;
-	struct poch_cbuf_header *header;
-	struct page *header_pg;
-	unsigned long header_size;
 
 	/* Last group consumed by user space. */
 	unsigned int consumed;
@@ -329,14 +326,12 @@ static ssize_t show_mmap_size(struct device *dev,
 	int len;
 	unsigned long mmap_size;
 	unsigned long group_pages;
-	unsigned long header_pages;
 	unsigned long total_group_pages;
 
 	group_pages = npages(channel->group_size);
-	header_pages = npages(channel->header_size);
 	total_group_pages = group_pages * channel->group_count;
 
-	mmap_size = (header_pages + total_group_pages) * PAGE_SIZE;
+	mmap_size = total_group_pages * PAGE_SIZE;
 	len = sprintf(buf, "%lu\n", mmap_size);
 	return len;
 }
@@ -369,10 +364,8 @@ static int poch_channel_alloc_groups(struct channel_info *channel)
 {
 	unsigned long i;
 	unsigned long group_pages;
-	unsigned long header_pages;
 
 	group_pages = npages(channel->group_size);
-	header_pages = npages(channel->header_size);
 
 	for (i = 0; i < channel->group_count; i++) {
 		struct poch_group_info *group;
@@ -402,8 +395,7 @@ static int poch_channel_alloc_groups(struct channel_info *channel)
 		 * this?
 		 */
 		group->dma_addr = page_to_pfn(group->pg) * PAGE_SIZE;
-		group->user_offset =
-			(header_pages + (i * group_pages)) * PAGE_SIZE;
+		group->user_offset = (i * group_pages) * PAGE_SIZE;
 
 		printk(KERN_INFO PFX "%ld: user_offset: 0x%lx\n", i,
 		       group->user_offset);
@@ -525,56 +517,6 @@ static void channel_dma_init(struct channel_info *channel)
 
 }
 
-static int poch_channel_alloc_header(struct channel_info *channel)
-{
-	struct poch_cbuf_header *header = channel->header;
-	unsigned long group_offset_size;
-	unsigned long tot_group_offsets_size;
-
-	/* Allocate memory to hold header exported userspace */
-	group_offset_size = sizeof(header->group_offsets[0]);
-	tot_group_offsets_size = group_offset_size * channel->group_count;
-	channel->header_size = sizeof(*header) + tot_group_offsets_size;
-	channel->header_pg = alloc_pages(GFP_KERNEL | __GFP_ZERO,
-					 get_order(channel->header_size));
-	if (!channel->header_pg)
-		return -ENOMEM;
-
-	channel->header = page_address(channel->header_pg);
-
-	return 0;
-}
-
-static void poch_channel_free_header(struct channel_info *channel)
-{
-	unsigned int order;
-
-	order = get_order(channel->header_size);
-	__free_pages(channel->header_pg, order);
-}
-
-static void poch_channel_init_header(struct channel_info *channel)
-{
-	int i;
-	struct poch_group_info *groups;
-	s32 *group_offsets;
-
-	channel->header->group_size_bytes = channel->group_size;
-	channel->header->group_count = channel->group_count;
-
-	spin_lock_init(&channel->group_offsets_lock);
-
-	group_offsets = channel->header->group_offsets;
-	groups = channel->groups;
-
-	for (i = 0; i < channel->group_count; i++) {
-		if (channel->dir == CHANNEL_DIR_RX)
-			group_offsets[i] = -1;
-		else
-			group_offsets[i] = groups[i].user_offset;
-	}
-}
-
 static void __poch_channel_clear_counters(struct channel_info *channel)
 {
 	channel->counters.pll_unlock = 0;
@@ -617,12 +559,6 @@ static int poch_channel_init(struct channel_info *channel,
 		goto out_free_group_info;
 	}
 
-	ret = poch_channel_alloc_header(channel);
-	if (ret) {
-		dev_err(dev, "error allocating user space header\n");
-		goto out_free_groups;
-	}
-
 	channel->fpga_iomem = poch_dev->fpga_iomem;
 	channel->bridge_iomem = poch_dev->bridge_iomem;
 	channel->iomem_lock = &poch_dev->iomem_lock;
@@ -630,14 +566,8 @@ static int poch_channel_init(struct channel_info *channel,
 
 	__poch_channel_clear_counters(channel);
 
-	printk(KERN_WARNING "poch_channel_init_header\n");
-
-	poch_channel_init_header(channel);
-
 	return 0;
 
- out_free_groups:
-	poch_channel_free_groups(channel);
  out_free_group_info:
 	kfree(channel->groups);
  out:
@@ -881,7 +811,6 @@ static int poch_release(struct inode *inode, struct file *filp)
 	}
 
 	atomic_dec(&channel->inited);
-	poch_channel_free_header(channel);
 	poch_channel_free_groups(channel);
 	kfree(channel->groups);
 	atomic_inc(&channel->free);
@@ -890,7 +819,7 @@ static int poch_release(struct inode *inode, struct file *filp)
 }
 
 /*
- * Map the header and the group buffers, to user space.
+ * Map the the group buffers, to user space.
  */
 static int poch_mmap(struct file *filp, struct vm_area_struct *vma)
 {
@@ -900,7 +829,6 @@ static int poch_mmap(struct file *filp, struct vm_area_struct *vma)
 	unsigned long size;
 
 	unsigned long group_pages;
-	unsigned long header_pages;
 	unsigned long total_group_pages;
 
 	int pg_num;
@@ -917,30 +845,16 @@ static int poch_mmap(struct file *filp, struct vm_area_struct *vma)
 	}
 
 	group_pages = npages(channel->group_size);
-	header_pages = npages(channel->header_size);
 	total_group_pages = group_pages * channel->group_count;
 
 	size = vma->vm_end - vma->vm_start;
-	if (size != (header_pages + total_group_pages) * PAGE_SIZE) {
+	if (size != total_group_pages * PAGE_SIZE) {
 		printk(KERN_WARNING PFX "required %lu bytes\n", size);
 		return -EINVAL;
 	}
 
 	start = vma->vm_start;
 
-	/* FIXME: Cleanup required on failure? */
-	pg = channel->header_pg;
-	for (pg_num = 0; pg_num < header_pages; pg_num++, pg++) {
-		printk(KERN_DEBUG PFX "page_count: %d\n", page_count(pg));
-		printk(KERN_DEBUG PFX "%d: header: 0x%lx\n", pg_num, start);
-		ret = vm_insert_page(vma, start, pg);
-		if (ret) {
-			printk(KERN_DEBUG "vm_insert 1 failed at %lx\n", start);
-			return ret;
-		}
-		start += PAGE_SIZE;
-	}
-
 	for (i = 0; i < channel->group_count; i++) {
 		pg = channel->groups[i].pg;
 		for (pg_num = 0; pg_num < group_pages; pg_num++, pg++) {
@@ -967,20 +881,16 @@ static int poch_mmap(struct file *filp, struct vm_area_struct *vma)
  */
 static int poch_channel_available(struct channel_info *channel)
 {
-	int i;
+	int available = 0;
 
 	spin_lock_irq(&channel->group_offsets_lock);
 
-	for (i = 0; i < channel->group_count; i++) {
-		if (channel->header->group_offsets[i] != -1) {
-			spin_unlock_irq(&channel->group_offsets_lock);
-			return 1;
-		}
-	}
+	if (channel->consumed != channel->transfer)
+		available = 1;
 
 	spin_unlock_irq(&channel->group_offsets_lock);
 
-	return 0;
+	return available;
 }
 
 static unsigned int poch_poll(struct file *filp, poll_table *pt)
@@ -1138,7 +1048,6 @@ static void poch_irq_dma(struct channel_info *channel)
 	long groups_done;
 	unsigned long i, j;
 	struct poch_group_info *groups;
-	s32 *group_offsets;
 	u32 curr_group_reg;
 
 	if (!atomic_read(&channel->inited))
@@ -1158,14 +1067,12 @@ static void poch_irq_dma(struct channel_info *channel)
 	if (groups_done <= 0)
 		groups_done += channel->group_count;
 
-	group_offsets = channel->header->group_offsets;
 	groups = channel->groups;
 
 	spin_lock(&channel->group_offsets_lock);
 
 	for (i = 0; i < groups_done; i++) {
 		j = (prev_transfer + i) % channel->group_count;
-		group_offsets[j] = groups[j].user_offset;
 
 		channel->transfer += 1;
 		channel->transfer %= channel->group_count;

drivers/staging/poch/poch.h

@@ -7,12 +7,6 @@
  * include/linux for final version.
  *
  */
-struct poch_cbuf_header {
-	__s32 group_size_bytes;
-	__s32 group_count;
-	__s32 group_offsets[0];
-};
-
 struct poch_counters {
 	__u32 fifo_empty;
 	__u32 fifo_overflow;