diff options
author | H Hartley Sweeten <hsweeten@visionengravers.com> | 2013-01-09 20:25:06 (GMT) |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-18 00:53:58 (GMT) |
commit | ea082fb1b0ee42b6430c83a6dc9d795381a87264 (patch) | |
tree | f11d563c8bd03b09d0bc63ef8bb0e60ca011076c /drivers/staging/comedi/comedi_buf.c | |
parent | d18431325be0d485f58097755de5ec90091f336d (diff) | |
download | linux-fsl-qoriq-ea082fb1b0ee42b6430c83a6dc9d795381a87264.tar.xz |
staging: comedi: separate out comedi_buf_* functions
Create a new file, comedi_buf.c, to hold all the comedi_async buffer
functions. Currently they are all in drivers.c and really don't have
any association with that source file.
Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Signed-off-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/staging/comedi/comedi_buf.c')
-rw-r--r-- | drivers/staging/comedi/comedi_buf.c | 421 |
1 files changed, 421 insertions, 0 deletions
diff --git a/drivers/staging/comedi/comedi_buf.c b/drivers/staging/comedi/comedi_buf.c new file mode 100644 index 0000000..fe2dcae --- /dev/null +++ b/drivers/staging/comedi/comedi_buf.c @@ -0,0 +1,421 @@ +/* + * comedi_buf.c + * + * COMEDI - Linux Control and Measurement Device Interface + * Copyright (C) 1997-2000 David A. Schleef <ds@schleef.org> + * + * 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. + * + * 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. + */ + +#include "comedidev.h" +#include "comedi_internal.h" + +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 */ + if (async->prealloc_buf) { + vunmap(async->prealloc_buf); + async->prealloc_buf = NULL; + async->prealloc_bufsz = 0; + } + if (async->buf_page_list) { + unsigned i; + for (i = 0; i < async->n_buf_pages; ++i) { + if (async->buf_page_list[i].virt_addr) { + clear_bit(PG_reserved, + &(virt_to_page(async->buf_page_list[i]. + virt_addr)->flags)); + if (s->async_dma_dir != DMA_NONE) { + dma_free_coherent(dev->hw_dev, + PAGE_SIZE, + async-> + buf_page_list + [i].virt_addr, + async-> + buf_page_list + [i].dma_addr); + } else { + free_page((unsigned long) + async->buf_page_list[i]. + virt_addr); + } + } + } + vfree(async->buf_page_list); + async->buf_page_list = NULL; + async->n_buf_pages = 0; + } + /* allocate new buffer */ + if (new_size) { + unsigned i = 0; + unsigned n_pages = new_size >> PAGE_SHIFT; + struct page **pages = NULL; + + async->buf_page_list = + vzalloc(sizeof(struct comedi_buf_page) * n_pages); + if (async->buf_page_list) + pages = vmalloc(sizeof(struct page *) * n_pages); + + if (pages) { + for (i = 0; i < n_pages; i++) { + if (s->async_dma_dir != DMA_NONE) { + async->buf_page_list[i].virt_addr = + dma_alloc_coherent(dev->hw_dev, + PAGE_SIZE, + &async-> + buf_page_list + [i].dma_addr, + GFP_KERNEL | + __GFP_COMP); + } else { + async->buf_page_list[i].virt_addr = + (void *) + get_zeroed_page(GFP_KERNEL); + } + if (async->buf_page_list[i].virt_addr == NULL) + break; + + set_bit(PG_reserved, + &(virt_to_page(async->buf_page_list[i]. + virt_addr)->flags)); + pages[i] = virt_to_page(async->buf_page_list[i]. + virt_addr); + } + } + if (i == n_pages) { + async->prealloc_buf = +#ifdef PAGE_KERNEL_NOCACHE + vmap(pages, n_pages, VM_MAP, PAGE_KERNEL_NOCACHE); +#else + vmap(pages, n_pages, VM_MAP, PAGE_KERNEL); +#endif + } + vfree(pages); + + if (async->prealloc_buf == NULL) { + /* Some allocation failed above. */ + if (async->buf_page_list) { + for (i = 0; i < n_pages; i++) { + if (async->buf_page_list[i].virt_addr == + NULL) { + break; + } + clear_bit(PG_reserved, + &(virt_to_page(async-> + buf_page_list[i]. + virt_addr)->flags)); + if (s->async_dma_dir != DMA_NONE) { + dma_free_coherent(dev->hw_dev, + PAGE_SIZE, + async-> + buf_page_list + [i].virt_addr, + async-> + buf_page_list + [i].dma_addr); + } else { + free_page((unsigned long) + async->buf_page_list + [i].virt_addr); + } + } + vfree(async->buf_page_list); + async->buf_page_list = NULL; + } + return -ENOMEM; + } + async->n_buf_pages = n_pages; + } + async->prealloc_bufsz = new_size; + + return 0; +} + +void comedi_reset_async_buf(struct comedi_async *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->scan_progress = 0; + async->munge_chan = 0; + async->munge_count = 0; + async->munge_ptr = 0; + + async->events = 0; +} + +unsigned int comedi_buf_write_n_available(struct comedi_async *async) +{ + unsigned int free_end; + unsigned int nbytes; + + if (async == NULL) + return 0; + + free_end = async->buf_read_count + async->prealloc_bufsz; + nbytes = free_end - async->buf_write_alloc_count; + nbytes -= nbytes % bytes_per_sample(async->subdevice); + /* barrier insures the read of buf_read_count in this + query occurs before any following writes to the buffer which + might be based on the return value from this query. + */ + smp_mb(); + return nbytes; +} + +/* allocates chunk for the writer from free buffer space */ +unsigned int comedi_buf_write_alloc(struct comedi_async *async, + unsigned int nbytes) +{ + unsigned int free_end = async->buf_read_count + async->prealloc_bufsz; + + if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) + nbytes = free_end - async->buf_write_alloc_count; + + async->buf_write_alloc_count += nbytes; + /* barrier insures the read of buf_read_count above occurs before + we write data to the write-alloc'ed buffer space */ + smp_mb(); + return nbytes; +} +EXPORT_SYMBOL(comedi_buf_write_alloc); + +/* allocates nothing unless it can completely fulfill the request */ +unsigned int comedi_buf_write_alloc_strict(struct comedi_async *async, + unsigned int nbytes) +{ + unsigned int free_end = async->buf_read_count + async->prealloc_bufsz; + + if ((int)(async->buf_write_alloc_count + nbytes - free_end) > 0) + nbytes = 0; + + async->buf_write_alloc_count += nbytes; + /* barrier insures the read of buf_read_count above occurs before + we write data to the write-alloc'ed buffer space */ + smp_mb(); + return nbytes; +} + +/* munging is applied to data by core as it passes between user + * and kernel space */ +static unsigned int comedi_buf_munge(struct comedi_async *async, + unsigned int num_bytes) +{ + struct comedi_subdevice *s = async->subdevice; + unsigned int count = 0; + const unsigned num_sample_bytes = bytes_per_sample(s); + + if (s->munge == NULL || (async->cmd.flags & CMDF_RAWDATA)) { + async->munge_count += num_bytes; + BUG_ON((int)(async->munge_count - async->buf_write_count) > 0); + return num_bytes; + } + /* don't munge partial samples */ + num_bytes -= num_bytes % num_sample_bytes; + while (count < num_bytes) { + int block_size; + + block_size = num_bytes - count; + if (block_size < 0) { + dev_warn(s->device->class_dev, + "%s: %s: bug! block_size is negative\n", + __FILE__, __func__); + break; + } + if ((int)(async->munge_ptr + block_size - + async->prealloc_bufsz) > 0) + block_size = async->prealloc_bufsz - async->munge_ptr; + + s->munge(s->device, s, async->prealloc_buf + async->munge_ptr, + block_size, async->munge_chan); + + smp_wmb(); /* barrier insures data is munged in buffer + * before munge_count is incremented */ + + 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; + } + BUG_ON((int)(async->munge_count - async->buf_write_count) > 0); + return count; +} + +/* transfers a chunk from writer to filled buffer space */ +unsigned comedi_buf_write_free(struct comedi_async *async, unsigned int nbytes) +{ + if ((int)(async->buf_write_count + nbytes - + async->buf_write_alloc_count) > 0) { + dev_info(async->subdevice->device->class_dev, + "attempted to write-free more bytes than have been write-allocated.\n"); + nbytes = async->buf_write_alloc_count - async->buf_write_count; + } + async->buf_write_count += nbytes; + async->buf_write_ptr += nbytes; + comedi_buf_munge(async, 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(comedi_buf_write_free); + +unsigned int comedi_buf_read_n_available(struct comedi_async *async) +{ + unsigned num_bytes; + + if (async == NULL) + return 0; + num_bytes = async->munge_count - async->buf_read_count; + /* barrier insures the read of munge_count in this + query occurs before any following reads of the buffer which + might be based on the return value from this query. + */ + smp_rmb(); + return num_bytes; +} +EXPORT_SYMBOL(comedi_buf_read_n_available); + +/* allocates a chunk for the reader from filled (and munged) buffer space */ +unsigned comedi_buf_read_alloc(struct comedi_async *async, unsigned nbytes) +{ + if ((int)(async->buf_read_alloc_count + nbytes - async->munge_count) > + 0) { + nbytes = async->munge_count - async->buf_read_alloc_count; + } + async->buf_read_alloc_count += nbytes; + /* barrier insures read of munge_count occurs before we actually read + data out of buffer */ + smp_rmb(); + return nbytes; +} +EXPORT_SYMBOL(comedi_buf_read_alloc); + +/* transfers control of a chunk from reader to free buffer space */ +unsigned comedi_buf_read_free(struct comedi_async *async, unsigned int nbytes) +{ + /* barrier insures data has been read out of + * buffer before read count is incremented */ + smp_mb(); + if ((int)(async->buf_read_count + nbytes - + async->buf_read_alloc_count) > 0) { + dev_info(async->subdevice->device->class_dev, + "attempted to read-free more bytes than have been read-allocated.\n"); + nbytes = async->buf_read_alloc_count - async->buf_read_count; + } + async->buf_read_count += nbytes; + async->buf_read_ptr += nbytes; + async->buf_read_ptr %= async->prealloc_bufsz; + return nbytes; +} +EXPORT_SYMBOL(comedi_buf_read_free); + +int comedi_buf_put(struct comedi_async *async, short x) +{ + unsigned int n = comedi_buf_write_alloc_strict(async, sizeof(short)); + + if (n < sizeof(short)) { + async->events |= COMEDI_CB_ERROR; + return 0; + } + *(short *)(async->prealloc_buf + async->buf_write_ptr) = x; + comedi_buf_write_free(async, sizeof(short)); + return 1; +} +EXPORT_SYMBOL(comedi_buf_put); + +int comedi_buf_get(struct comedi_async *async, short *x) +{ + unsigned int n = comedi_buf_read_n_available(async); + + if (n < sizeof(short)) + return 0; + comedi_buf_read_alloc(async, sizeof(short)); + *x = *(short *)(async->prealloc_buf + async->buf_read_ptr); + comedi_buf_read_free(async, sizeof(short)); + return 1; +} +EXPORT_SYMBOL(comedi_buf_get); + +void comedi_buf_memcpy_to(struct comedi_async *async, unsigned int offset, + const void *data, unsigned int num_bytes) +{ + unsigned int write_ptr = async->buf_write_ptr + offset; + + if (write_ptr >= async->prealloc_bufsz) + write_ptr %= async->prealloc_bufsz; + + 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; + } +} +EXPORT_SYMBOL(comedi_buf_memcpy_to); + +void comedi_buf_memcpy_from(struct comedi_async *async, unsigned int offset, + void *dest, unsigned int nbytes) +{ + void *src; + unsigned int read_ptr = async->buf_read_ptr + offset; + + if (read_ptr >= async->prealloc_bufsz) + read_ptr %= async->prealloc_bufsz; + + 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; + } +} +EXPORT_SYMBOL(comedi_buf_memcpy_from); |