Initial import

1 files changed, 550 insertions, 0 deletions

diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c
new file mode 100644
index 000000000..19e7b229d
--- /dev/null
+++ b/drivers/staging/comedi/comedi_buf.c
@@ -0,0 +1,550 @@
+/*
+ * comedi_buf.c
+ *
+ * COMEDI - Linux Control and Measurement Device Interface
+ * Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org>
+ * Copyright (C) 2002 Frank Mori Hess <fmhess@users.sourceforge.net>
+ *
+ * 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.
+ */
+
+#include <linux/vmalloc.h>
+#include <linux/slab.h>
+
+#include "comedidev.h"
+#include "comedi_internal.h"
+
+#ifdef PAGE_KERNEL_NOCACHE
+#define COMEDI_PAGE_PROTECTION		PAGE_KERNEL_NOCACHE
+#else
+#define COMEDI_PAGE_PROTECTION		PAGE_KERNEL
+#endif
+
+static void comedi_buf_map_kref_release(struct kref *kref)
+{
+	struct comedi_buf_map *bm =
+		container_of(kref, struct comedi_buf_map, refcount);
+	struct comedi_buf_page *buf;
+	unsigned int i;
+
+	if (bm->page_list) {
+		for (i = 0; i < bm->n_pages; i++) {
+			buf = &bm->page_list[i];
+			clear_bit(PG_reserved,
+				  &(virt_to_page(buf->virt_addr)->flags));
+			if (bm->dma_dir != DMA_NONE) {
+#ifdef CONFIG_HAS_DMA
+				dma_free_coherent(bm->dma_hw_dev,
+						  PAGE_SIZE,
+						  buf->virt_addr,
+						  buf->dma_addr);
+#endif
+			} else {
+				free_page((unsigned long)buf->virt_addr);
+			}
+		}
+		vfree(bm->page_list);
+	}
+	if (bm->dma_dir != DMA_NONE)
+		put_device(bm->dma_hw_dev);
+	kfree(bm);
+}
+
+static void __comedi_buf_free(struct comedi_device *dev,
+			      struct comedi_subdevice *s)
+{
+	struct comedi_async *async = s->async;
+	struct comedi_buf_map *bm;
+	unsigned long flags;
+
+	if (async->prealloc_buf) {
+		vunmap(async->prealloc_buf);
+		async->prealloc_buf = NULL;
+		async->prealloc_bufsz = 0;
+	}
+
+	spin_lock_irqsave(&s->spin_lock, flags);
+	bm = async->buf_map;
+	async->buf_map = NULL;
+	spin_unlock_irqrestore(&s->spin_lock, flags);
+	comedi_buf_map_put(bm);
+}
+
+static void __comedi_buf_alloc(struct comedi_device *dev,
+			       struct comedi_subdevice *s,
+			       unsigned n_pages)
+{
+	struct comedi_async *async = s->async;
+	struct page **pages = NULL;
+	struct comedi_buf_map *bm;
+	struct comedi_buf_page *buf;
+	unsigned long flags;
+	unsigned i;
+
+	if (!IS_ENABLED(CONFIG_HAS_DMA) && s->async_dma_dir != DMA_NONE) {
+		dev_err(dev->class_dev,
+			"dma buffer allocation not supported\n");
+		return;
+	}
+
+	bm = kzalloc(sizeof(*async->buf_map), GFP_KERNEL);
+	if (!bm)
+		return;
+
+	kref_init(&bm->refcount);
+	spin_lock_irqsave(&s->spin_lock, flags);
+	async->buf_map = bm;
+	spin_unlock_irqrestore(&s->spin_lock, flags);
+	bm->dma_dir = s->async_dma_dir;
+	if (bm->dma_dir != DMA_NONE)
+		/* Need ref to hardware device to free buffer later. */
+		bm->dma_hw_dev = get_device(dev->hw_dev);
+
+	bm->page_list = vzalloc(sizeof(*buf) * n_pages);
+	if (bm->page_list)
+		pages = vmalloc(sizeof(struct page *) * n_pages);
+
+	if (!pages)
+		return;
+
+	for (i = 0; i < n_pages; i++) {
+		buf = &bm->page_list[i];
+		if (bm->dma_dir != DMA_NONE)
+#ifdef CONFIG_HAS_DMA
+			buf->virt_addr = dma_alloc_coherent(bm->dma_hw_dev,
+							    PAGE_SIZE,
+							    &buf->dma_addr,
+							    GFP_KERNEL |
+							    __GFP_COMP);
+#else
+			break;
+#endif
+		else
+			buf->virt_addr = (void *)get_zeroed_page(GFP_KERNEL);
+		if (!buf->virt_addr)
+			break;
+
+		set_bit(PG_reserved, &(virt_to_page(buf->virt_addr)->flags));
+
+		pages[i] = virt_to_page(buf->virt_addr);
+	}
+	spin_lock_irqsave(&s->spin_lock, flags);
+	bm->n_pages = i;
+	spin_unlock_irqrestore(&s->spin_lock, flags);
+
+	/* vmap the prealloc_buf if all the pages were allocated */
+	if (i == n_pages)
+		async->prealloc_buf = vmap(pages, n_pages, VM_MAP,
+					   COMEDI_PAGE_PROTECTION);
+
+	vfree(pages);
+}
+
+void comedi_buf_map_get(struct comedi_buf_map *bm)
+{
+	if (bm)
+		kref_get(&bm->refcount);
+}
+
+int comedi_buf_map_put(struct comedi_buf_map *bm)
+{
+	if (bm)
+		return kref_put(&bm->refcount, comedi_buf_map_kref_release);
+	return 1;
+}
+
+/* returns s->async->buf_map and increments its kref refcount */
+struct comedi_buf_map *
+comedi_buf_map_from_subdev_get(struct comedi_subdevice *s)
+{
+	struct comedi_async *async = s->async;
+	struct comedi_buf_map *bm = NULL;
+	unsigned long flags;
+
+	if (!async)
+		return NULL;
+
+	spin_lock_irqsave(&s->spin_lock, flags);
+	bm = async->buf_map;
+	/* only want it if buffer pages allocated */
+	if (bm && bm->n_pages)
+		comedi_buf_map_get(bm);
+	else
+		bm = NULL;
+	spin_unlock_irqrestore(&s->spin_lock, flags);
+
+	return bm;
+}
+
+bool comedi_buf_is_mmapped(struct comedi_subdevice *s)
+{
+	struct comedi_buf_map *bm = s->async->buf_map;
+
+	return bm && (atomic_read(&bm->refcount.refcount) > 1);
+}
+
+int comedi_buf_alloc(struct comedi_device *dev, struct comedi_subdevice *s,
+		     unsigned long new_size)
+{
+	struct comedi_async *async = s->async;
+
+	/* Round up new_size to multiple of PAGE_SIZE */
+	new_size = (new_size + PAGE_SIZE - 1) & PAGE_MASK;
+
+	/* if no change is required, do nothing */
+	if (async->prealloc_buf && async->prealloc_bufsz == new_size)
+		return 0;
+
+	/* deallocate old buffer */
+	__comedi_buf_free(dev, s);
+
+	/* allocate new buffer */
+	if (new_size) {
+		unsigned n_pages = new_size >> PAGE_SHIFT;
+
+		__comedi_buf_alloc(dev, s, n_pages);
+
+		if (!async->prealloc_buf) {
+			/* allocation failed */
+			__comedi_buf_free(dev, s);
+			return -ENOMEM;
+		}
+	}
+	async->prealloc_bufsz = new_size;
+
+	return 0;
+}
+
+void comedi_buf_reset(struct comedi_subdevice *s)
+{
+	struct comedi_async *async = s->async;
+
+	async->buf_write_alloc_count = 0;
+	async->buf_write_count = 0;
+	async->buf_read_alloc_count = 0;
+	async->buf_read_count = 0;
+
+	async->buf_write_ptr = 0;
+	async->buf_read_ptr = 0;
+
+	async->cur_chan = 0;
+	async->scans_done = 0;
+	async->scan_progress = 0;
+	async->munge_chan = 0;
+	async->munge_count = 0;
+	async->munge_ptr = 0;
+
+	async->events = 0;
+}
+
+static unsigned int comedi_buf_write_n_available(struct comedi_subdevice *s)
+{
+	struct comedi_async *async = s->async;
+	unsigned int free_end = async->buf_read_count + async->prealloc_bufsz;
+
+	return free_end - async->buf_write_alloc_count;
+}
+
+/* allocates chunk for the writer from free buffer space */
+unsigned int comedi_buf_write_alloc(struct comedi_subdevice *s,
+				    unsigned int nbytes)
+{
+	struct comedi_async *async = s->async;
+	unsigned int available = comedi_buf_write_n_available(s);
+
+	if (nbytes > available)
+		nbytes = available;
+
+	async->buf_write_alloc_count += nbytes;
+
+	/*
+	 * ensure the async buffer 'counts' are read and updated
+	 * before we write data to the write-alloc'ed buffer space
+	 */
+	smp_mb();
+
+	return nbytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_write_alloc);
+
+/*
+ * munging is applied to data by core as it passes between user
+ * and kernel space
+ */
+static unsigned int comedi_buf_munge(struct comedi_subdevice *s,
+				     unsigned int num_bytes)
+{
+	struct comedi_async *async = s->async;
+	unsigned int count = 0;
+	const unsigned num_sample_bytes = comedi_bytes_per_sample(s);
+
+	if (!s->munge || (async->cmd.flags & CMDF_RAWDATA)) {
+		async->munge_count += num_bytes;
+		count = num_bytes;
+	} else {
+		/* don't munge partial samples */
+		num_bytes -= num_bytes % num_sample_bytes;
+		while (count < num_bytes) {
+			int block_size = num_bytes - count;
+			unsigned int buf_end;
+
+			buf_end = async->prealloc_bufsz - async->munge_ptr;
+			if (block_size > buf_end)
+				block_size = buf_end;
+
+			s->munge(s->device, s,
+				 async->prealloc_buf + async->munge_ptr,
+				 block_size, async->munge_chan);
+
+			/*
+			 * ensure data is munged in buffer before the
+			 * async buffer munge_count is incremented
+			 */
+			smp_wmb();
+
+			async->munge_chan += block_size / num_sample_bytes;
+			async->munge_chan %= async->cmd.chanlist_len;
+			async->munge_count += block_size;
+			async->munge_ptr += block_size;
+			async->munge_ptr %= async->prealloc_bufsz;
+			count += block_size;
+		}
+	}
+
+	return count;
+}
+
+unsigned int comedi_buf_write_n_allocated(struct comedi_subdevice *s)
+{
+	struct comedi_async *async = s->async;
+
+	return async->buf_write_alloc_count - async->buf_write_count;
+}
+
+/* transfers a chunk from writer to filled buffer space */
+unsigned int comedi_buf_write_free(struct comedi_subdevice *s,
+				   unsigned int nbytes)
+{
+	struct comedi_async *async = s->async;
+	unsigned int allocated = comedi_buf_write_n_allocated(s);
+
+	if (nbytes > allocated)
+		nbytes = allocated;
+
+	async->buf_write_count += nbytes;
+	async->buf_write_ptr += nbytes;
+	comedi_buf_munge(s, async->buf_write_count - async->munge_count);
+	if (async->buf_write_ptr >= async->prealloc_bufsz)
+		async->buf_write_ptr %= async->prealloc_bufsz;
+
+	return nbytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_write_free);
+
+unsigned int comedi_buf_read_n_available(struct comedi_subdevice *s)
+{
+	struct comedi_async *async = s->async;
+	unsigned num_bytes;
+
+	if (!async)
+		return 0;
+
+	num_bytes = async->munge_count - async->buf_read_count;
+
+	/*
+	 * ensure the async buffer 'counts' are read before we
+	 * attempt to read data from the buffer
+	 */
+	smp_rmb();
+
+	return num_bytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_read_n_available);
+
+/* allocates a chunk for the reader from filled (and munged) buffer space */
+unsigned int comedi_buf_read_alloc(struct comedi_subdevice *s,
+				   unsigned int nbytes)
+{
+	struct comedi_async *async = s->async;
+	unsigned int available;
+
+	available = async->munge_count - async->buf_read_alloc_count;
+	if (nbytes > available)
+		nbytes = available;
+
+	async->buf_read_alloc_count += nbytes;
+
+	/*
+	 * ensure the async buffer 'counts' are read before we
+	 * attempt to read data from the read-alloc'ed buffer space
+	 */
+	smp_rmb();
+
+	return nbytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_read_alloc);
+
+static unsigned int comedi_buf_read_n_allocated(struct comedi_async *async)
+{
+	return async->buf_read_alloc_count - async->buf_read_count;
+}
+
+/* transfers control of a chunk from reader to free buffer space */
+unsigned int comedi_buf_read_free(struct comedi_subdevice *s,
+				  unsigned int nbytes)
+{
+	struct comedi_async *async = s->async;
+	unsigned int allocated;
+
+	/*
+	 * ensure data has been read out of buffer before
+	 * the async read count is incremented
+	 */
+	smp_mb();
+
+	allocated = comedi_buf_read_n_allocated(async);
+	if (nbytes > allocated)
+		nbytes = allocated;
+
+	async->buf_read_count += nbytes;
+	async->buf_read_ptr += nbytes;
+	async->buf_read_ptr %= async->prealloc_bufsz;
+	return nbytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_read_free);
+
+static void comedi_buf_memcpy_to(struct comedi_subdevice *s,
+				 const void *data, unsigned int num_bytes)
+{
+	struct comedi_async *async = s->async;
+	unsigned int write_ptr = async->buf_write_ptr;
+
+	while (num_bytes) {
+		unsigned int block_size;
+
+		if (write_ptr + num_bytes > async->prealloc_bufsz)
+			block_size = async->prealloc_bufsz - write_ptr;
+		else
+			block_size = num_bytes;
+
+		memcpy(async->prealloc_buf + write_ptr, data, block_size);
+
+		data += block_size;
+		num_bytes -= block_size;
+
+		write_ptr = 0;
+	}
+}
+
+static void comedi_buf_memcpy_from(struct comedi_subdevice *s,
+				   void *dest, unsigned int nbytes)
+{
+	void *src;
+	struct comedi_async *async = s->async;
+	unsigned int read_ptr = async->buf_read_ptr;
+
+	while (nbytes) {
+		unsigned int block_size;
+
+		src = async->prealloc_buf + read_ptr;
+
+		if (nbytes >= async->prealloc_bufsz - read_ptr)
+			block_size = async->prealloc_bufsz - read_ptr;
+		else
+			block_size = nbytes;
+
+		memcpy(dest, src, block_size);
+		nbytes -= block_size;
+		dest += block_size;
+		read_ptr = 0;
+	}
+}
+
+/**
+ * comedi_buf_write_samples - write sample data to comedi buffer
+ * @s: comedi_subdevice struct
+ * @data: samples
+ * @nsamples: number of samples
+ *
+ * Writes nsamples to the comedi buffer associated with the subdevice, marks
+ * it as written and updates the acquisition scan progress.
+ *
+ * Returns the amount of data written in bytes.
+ */
+unsigned int comedi_buf_write_samples(struct comedi_subdevice *s,
+				      const void *data, unsigned int nsamples)
+{
+	unsigned int max_samples;
+	unsigned int nbytes;
+
+	/*
+	 * Make sure there is enough room in the buffer for all the samples.
+	 * If not, clamp the nsamples to the number that will fit, flag the
+	 * buffer overrun and add the samples that fit.
+	 */
+	max_samples = comedi_bytes_to_samples(s,
+					      comedi_buf_write_n_available(s));
+	if (nsamples > max_samples) {
+		dev_warn(s->device->class_dev, "buffer overrun\n");
+		s->async->events |= COMEDI_CB_OVERFLOW;
+		nsamples = max_samples;
+	}
+
+	if (nsamples == 0)
+		return 0;
+
+	nbytes = comedi_buf_write_alloc(s,
+					comedi_samples_to_bytes(s, nsamples));
+	comedi_buf_memcpy_to(s, data, nbytes);
+	comedi_buf_write_free(s, nbytes);
+	comedi_inc_scan_progress(s, nbytes);
+	s->async->events |= COMEDI_CB_BLOCK;
+
+	return nbytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_write_samples);
+
+/**
+ * comedi_buf_read_samples - read sample data from comedi buffer
+ * @s: comedi_subdevice struct
+ * @data: destination
+ * @nsamples: maximum number of samples to read
+ *
+ * Reads up to nsamples from the comedi buffer associated with the subdevice,
+ * marks it as read and updates the acquisition scan progress.
+ *
+ * Returns the amount of data read in bytes.
+ */
+unsigned int comedi_buf_read_samples(struct comedi_subdevice *s,
+				     void *data, unsigned int nsamples)
+{
+	unsigned int max_samples;
+	unsigned int nbytes;
+
+	/* clamp nsamples to the number of full samples available */
+	max_samples = comedi_bytes_to_samples(s,
+					      comedi_buf_read_n_available(s));
+	if (nsamples > max_samples)
+		nsamples = max_samples;
+
+	if (nsamples == 0)
+		return 0;
+
+	nbytes = comedi_buf_read_alloc(s,
+				       comedi_samples_to_bytes(s, nsamples));
+	comedi_buf_memcpy_from(s, data, nbytes);
+	comedi_buf_read_free(s, nbytes);
+	comedi_inc_scan_progress(s, nbytes);
+	s->async->events |= COMEDI_CB_BLOCK;
+
+	return nbytes;
+}
+EXPORT_SYMBOL_GPL(comedi_buf_read_samples);