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staging: comedi: mite: move the mite ring functions

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For aesthetics, move the functions that allocate/free and initialize
the mite dma ring. They are currently kind of scattered around the
code.

Add docbook comments for the exported functions.

Signed-off-by: H Hartley Sweeten <hsweeten@visionengravers.com>
Reviewed-by: Ian Abbott <abbotti@mev.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
H Hartley Sweeten 2016-05-02 10:11:47 -07:00 committed by Greg Kroah-Hartman
parent a2163cc35a
commit fc53242394
2 changed files with 150 additions and 132 deletions
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274
drivers/staging/comedi/drivers/mite.c
View File

@ -228,49 +228,6 @@ static unsigned int mite_fifo_size(struct mite *mite, unsigned int channel)
return empty_count + full_count;
}
struct mite_ring *mite_alloc_ring(struct mite *mite)
{
struct mite_ring *ring;
ring = kmalloc(sizeof(*ring), GFP_KERNEL);
if (!ring)
return NULL;
ring->hw_dev = get_device(&mite->pcidev->dev);
if (!ring->hw_dev) {
kfree(ring);
return NULL;
}
ring->n_links = 0;
ring->descs = NULL;
ring->dma_addr = 0;
return ring;
};
EXPORT_SYMBOL_GPL(mite_alloc_ring);
static void mite_free_dma_descs(struct mite_ring *ring)
{
struct mite_dma_desc *descs = ring->descs;
if (descs) {
dma_free_coherent(ring->hw_dev,
ring->n_links * sizeof(*descs),
descs, ring->dma_addr);
ring->descs = NULL;
ring->dma_addr = 0;
ring->n_links = 0;
}
}
void mite_free_ring(struct mite_ring *ring)
{
if (ring) {
mite_free_dma_descs(ring);
put_device(ring->hw_dev);
kfree(ring);
}
};
EXPORT_SYMBOL_GPL(mite_free_ring);
struct mite_channel *mite_request_channel_in_range(struct mite *mite,
struct mite_ring *ring,
unsigned int min_channel,
@ -343,92 +300,6 @@ void mite_dma_arm(struct mite_channel *mite_chan)
}
EXPORT_SYMBOL_GPL(mite_dma_arm);
/**************************************/
int mite_buf_change(struct mite_ring *ring,
struct comedi_subdevice *s)
{
struct comedi_async *async = s->async;
struct mite_dma_desc *descs;
unsigned int n_links;
mite_free_dma_descs(ring);
if (async->prealloc_bufsz == 0)
return 0;
n_links = async->prealloc_bufsz >> PAGE_SHIFT;
descs = dma_alloc_coherent(ring->hw_dev,
n_links * sizeof(*descs),
&ring->dma_addr, GFP_KERNEL);
if (!descs) {
dev_err(s->device->class_dev,
"mite: ring buffer allocation failed\n");
return -ENOMEM;
}
ring->descs = descs;
ring->n_links = n_links;
return mite_init_ring_descriptors(ring, s, n_links << PAGE_SHIFT);
}
EXPORT_SYMBOL_GPL(mite_buf_change);
/*
* initializes the ring buffer descriptors to provide correct DMA transfer links
* to the exact amount of memory required. When the ring buffer is allocated in
* mite_buf_change, the default is to initialize the ring to refer to the entire
* DMA data buffer. A command may call this function later to re-initialize and
* shorten the amount of memory that will be transferred.
*/
int mite_init_ring_descriptors(struct mite_ring *ring,
struct comedi_subdevice *s,
unsigned int nbytes)
{
struct comedi_async *async = s->async;
struct mite_dma_desc *desc = NULL;
unsigned int n_full_links = nbytes >> PAGE_SHIFT;
unsigned int remainder = nbytes % PAGE_SIZE;
int i;
dev_dbg(s->device->class_dev,
"mite: init ring buffer to %u bytes\n", nbytes);
if ((n_full_links + (remainder > 0 ? 1 : 0)) > ring->n_links) {
dev_err(s->device->class_dev,
"mite: ring buffer too small for requested init\n");
return -ENOMEM;
}
/* We set the descriptors for all full links. */
for (i = 0; i < n_full_links; ++i) {
desc = &ring->descs[i];
desc->count = cpu_to_le32(PAGE_SIZE);
desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);
desc->next = cpu_to_le32(ring->dma_addr +
(i + 1) * sizeof(*desc));
}
/* the last link is either a remainder or was a full link. */
if (remainder > 0) {
desc = &ring->descs[i];
/* set the lesser count for the remainder link */
desc->count = cpu_to_le32(remainder);
desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);
}
/* Assign the last link->next to point back to the head of the list. */
desc->next = cpu_to_le32(ring->dma_addr);
/*
* barrier is meant to insure that all the writes to the dma descriptors
* have completed before the dma controller is commanded to read them
*/
smp_wmb();
return 0;
}
EXPORT_SYMBOL_GPL(mite_init_ring_descriptors);
void mite_prep_dma(struct mite_channel *mite_chan,
unsigned int num_device_bits, unsigned int num_memory_bits)
{
@ -714,6 +585,151 @@ int mite_done(struct mite_channel *mite_chan)
}
EXPORT_SYMBOL_GPL(mite_done);
/**
* mite_init_ring_descriptors() - Initialize a MITE dma ring descriptors.
* @ring: MITE dma ring.
* @s: COMEDI subdevice.
* @nbytes: the size of the dma ring (in bytes).
*
* Initializes the ring buffer descriptors to provide correct DMA transfer
* links to the exact amount of memory required. When the ring buffer is
* allocated by mite_buf_change(), the default is to initialize the ring
* to refer to the entire DMA data buffer. A command may call this function
* later to re-initialize and shorten the amount of memory that will be
* transferred.
*/
int mite_init_ring_descriptors(struct mite_ring *ring,
struct comedi_subdevice *s,
unsigned int nbytes)
{
struct comedi_async *async = s->async;
struct mite_dma_desc *desc = NULL;
unsigned int n_full_links = nbytes >> PAGE_SHIFT;
unsigned int remainder = nbytes % PAGE_SIZE;
int i;
dev_dbg(s->device->class_dev,
"mite: init ring buffer to %u bytes\n", nbytes);
if ((n_full_links + (remainder > 0 ? 1 : 0)) > ring->n_links) {
dev_err(s->device->class_dev,
"mite: ring buffer too small for requested init\n");
return -ENOMEM;
}
/* We set the descriptors for all full links. */
for (i = 0; i < n_full_links; ++i) {
desc = &ring->descs[i];
desc->count = cpu_to_le32(PAGE_SIZE);
desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);
desc->next = cpu_to_le32(ring->dma_addr +
(i + 1) * sizeof(*desc));
}
/* the last link is either a remainder or was a full link. */
if (remainder > 0) {
desc = &ring->descs[i];
/* set the lesser count for the remainder link */
desc->count = cpu_to_le32(remainder);
desc->addr = cpu_to_le32(async->buf_map->page_list[i].dma_addr);
}
/* Assign the last link->next to point back to the head of the list. */
desc->next = cpu_to_le32(ring->dma_addr);
/*
* barrier is meant to insure that all the writes to the dma descriptors
* have completed before the dma controller is commanded to read them
*/
smp_wmb();
return 0;
}
EXPORT_SYMBOL_GPL(mite_init_ring_descriptors);
static void mite_free_dma_descs(struct mite_ring *ring)
{
struct mite_dma_desc *descs = ring->descs;
if (descs) {
dma_free_coherent(ring->hw_dev,
ring->n_links * sizeof(*descs),
descs, ring->dma_addr);
ring->descs = NULL;
ring->dma_addr = 0;
ring->n_links = 0;
}
}
/**
* mite_buf_change() - COMEDI subdevice (*buf_change) for a MITE dma ring.
* @ring: MITE dma ring.
* @s: COMEDI subdevice.
*/
int mite_buf_change(struct mite_ring *ring, struct comedi_subdevice *s)
{
struct comedi_async *async = s->async;
struct mite_dma_desc *descs;
unsigned int n_links;
mite_free_dma_descs(ring);
if (async->prealloc_bufsz == 0)
return 0;
n_links = async->prealloc_bufsz >> PAGE_SHIFT;
descs = dma_alloc_coherent(ring->hw_dev,
n_links * sizeof(*descs),
&ring->dma_addr, GFP_KERNEL);
if (!descs) {
dev_err(s->device->class_dev,
"mite: ring buffer allocation failed\n");
return -ENOMEM;
}
ring->descs = descs;
ring->n_links = n_links;
return mite_init_ring_descriptors(ring, s, n_links << PAGE_SHIFT);
}
EXPORT_SYMBOL_GPL(mite_buf_change);
/**
* mite_alloc_ring() - Allocate a MITE dma ring.
* @mite: MITE device.
*/
struct mite_ring *mite_alloc_ring(struct mite *mite)
{
struct mite_ring *ring;
ring = kmalloc(sizeof(*ring), GFP_KERNEL);
if (!ring)
return NULL;
ring->hw_dev = get_device(&mite->pcidev->dev);
if (!ring->hw_dev) {
kfree(ring);
return NULL;
}
ring->n_links = 0;
ring->descs = NULL;
ring->dma_addr = 0;
return ring;
}
EXPORT_SYMBOL_GPL(mite_alloc_ring);
/**
* mite_free_ring() - Free a MITE dma ring and its descriptors.
* @ring: MITE dma ring.
*/
void mite_free_ring(struct mite_ring *ring)
{
if (ring) {
mite_free_dma_descs(ring);
put_device(ring->hw_dev);
kfree(ring);
}
}
EXPORT_SYMBOL_GPL(mite_free_ring);
static int mite_setup(struct comedi_device *dev, struct mite *mite,
bool use_win1)
{

8
drivers/staging/comedi/drivers/mite.h
View File

@ -60,8 +60,6 @@ struct mite {
spinlock_t lock;
};
struct mite_ring *mite_alloc_ring(struct mite *);
void mite_free_ring(struct mite_ring *ring);
struct mite_channel *mite_request_channel_in_range(struct mite *,
struct mite_ring *,
unsigned int min_channel,
@ -86,9 +84,13 @@ int mite_done(struct mite_channel *mite_chan);
void mite_prep_dma(struct mite_channel *mite_chan,
unsigned int num_device_bits, unsigned int num_memory_bits);
int mite_buf_change(struct mite_ring *, struct comedi_subdevice *);
int mite_init_ring_descriptors(struct mite_ring *, struct comedi_subdevice *,
unsigned int nbytes);
int mite_buf_change(struct mite_ring *, struct comedi_subdevice *);
struct mite_ring *mite_alloc_ring(struct mite *);
void mite_free_ring(struct mite_ring *);
struct mite *mite_attach(struct comedi_device *, bool use_win1);
void mite_detach(struct mite *);