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staging: comedi: mite: tidy up mite dma channel request/release 

For aesthetics, make the actual "request" function static and change
mite_request_channel_in_range() into a wrapper that calls the internal
function. Change the inline function that requests any free channel
into an export that also calls the internal function.

Move the functions to a more logical spot in the code and 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 10:11:48 -07:00 committed by Greg Kroah-Hartman
parent fc53242394
commit c3c860b395
2 changed files with 91 additions and 67 deletions
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137
drivers/staging/comedi/drivers/mite.c
View File

@ -228,59 +228,6 @@ static unsigned int mite_fifo_size(struct mite *mite, unsigned int channel)
return empty_count + full_count;
}
struct mite_channel *mite_request_channel_in_range(struct mite *mite,
struct mite_ring *ring,
unsigned int min_channel,
unsigned int max_channel)
{
struct mite_channel *mite_chan = NULL;
unsigned long flags;
int i;
/*
* spin lock so mite_release_channel can be called safely
* from interrupts
*/
spin_lock_irqsave(&mite->lock, flags);
for (i = min_channel; i <= max_channel; ++i) {
mite_chan = &mite->channels[i];
if (!mite_chan->ring) {
mite_chan->ring = ring;
break;
}
mite_chan = NULL;
}
spin_unlock_irqrestore(&mite->lock, flags);
return mite_chan;
}
EXPORT_SYMBOL_GPL(mite_request_channel_in_range);
void mite_release_channel(struct mite_channel *mite_chan)
{
struct mite *mite = mite_chan->mite;
unsigned long flags;
/* spin lock to prevent races with mite_request_channel */
spin_lock_irqsave(&mite->lock, flags);
if (mite_chan->ring) {
mite_dma_disarm(mite_chan);
mite_dma_reset(mite_chan);
/*
* disable all channel's interrupts (do it after disarm/reset so
* MITE_CHCR reg isn't changed while dma is still active!)
*/
writel(CHCR_CLR_DMA_IE | CHCR_CLR_LINKP_IE |
CHCR_CLR_SAR_IE | CHCR_CLR_DONE_IE |
CHCR_CLR_MRDY_IE | CHCR_CLR_DRDY_IE |
CHCR_CLR_LC_IE | CHCR_CLR_CONT_RB_IE,
mite->mmio + MITE_CHCR(mite_chan->channel));
mite_chan->ring = NULL;
mmiowb();
}
spin_unlock_irqrestore(&mite->lock, flags);
}
EXPORT_SYMBOL_GPL(mite_release_channel);
void mite_dma_arm(struct mite_channel *mite_chan)
{
struct mite *mite = mite_chan->mite;
@ -585,6 +532,90 @@ int mite_done(struct mite_channel *mite_chan)
}
EXPORT_SYMBOL_GPL(mite_done);
static struct mite_channel *__mite_request_channel(struct mite *mite,
struct mite_ring *ring,
unsigned int min_channel,
unsigned int max_channel)
{
struct mite_channel *mite_chan = NULL;
unsigned long flags;
int i;
/*
* spin lock so mite_release_channel can be called safely
* from interrupts
*/
spin_lock_irqsave(&mite->lock, flags);
for (i = min_channel; i <= max_channel; ++i) {
mite_chan = &mite->channels[i];
if (!mite_chan->ring) {
mite_chan->ring = ring;
break;
}
mite_chan = NULL;
}
spin_unlock_irqrestore(&mite->lock, flags);
return mite_chan;
}
/**
* mite_request_channel_in_range() - Request a MITE dma channel.
* @mite: MITE device.
* @ring: MITE dma ring.
* @min_channel: minimum channel index to use.
* @max_channel: maximum channel index to use.
*/
struct mite_channel *mite_request_channel_in_range(struct mite *mite,
struct mite_ring *ring,
unsigned int min_channel,
unsigned int max_channel)
{
return __mite_request_channel(mite, ring, min_channel, max_channel);
}
EXPORT_SYMBOL_GPL(mite_request_channel_in_range);
/**
* mite_request_channel() - Request a MITE dma channel.
* @mite: MITE device.
* @ring: MITE dma ring.
*/
struct mite_channel *mite_request_channel(struct mite *mite,
struct mite_ring *ring)
{
return __mite_request_channel(mite, ring, 0, mite->num_channels - 1);
}
EXPORT_SYMBOL_GPL(mite_request_channel);
/**
* mite_release_channel() - Release a MITE dma channel.
* @mite_chan: MITE dma channel.
*/
void mite_release_channel(struct mite_channel *mite_chan)
{
struct mite *mite = mite_chan->mite;
unsigned long flags;
/* spin lock to prevent races with mite_request_channel */
spin_lock_irqsave(&mite->lock, flags);
if (mite_chan->ring) {
mite_dma_disarm(mite_chan);
mite_dma_reset(mite_chan);
/*
* disable all channel's interrupts (do it after disarm/reset so
* MITE_CHCR reg isn't changed while dma is still active!)
*/
writel(CHCR_CLR_DMA_IE | CHCR_CLR_LINKP_IE |
CHCR_CLR_SAR_IE | CHCR_CLR_DONE_IE |
CHCR_CLR_MRDY_IE | CHCR_CLR_DRDY_IE |
CHCR_CLR_LC_IE | CHCR_CLR_CONT_RB_IE,
mite->mmio + MITE_CHCR(mite_chan->channel));
mite_chan->ring = NULL;
mmiowb();
}
spin_unlock_irqrestore(&mite->lock, flags);
}
EXPORT_SYMBOL_GPL(mite_release_channel);
/**
* mite_init_ring_descriptors() - Initialize a MITE dma ring descriptors.
* @ring: MITE dma ring.

21
drivers/staging/comedi/drivers/mite.h
View File

@ -60,20 +60,6 @@ struct mite {
spinlock_t lock;
};
struct mite_channel *mite_request_channel_in_range(struct mite *,
struct mite_ring *,
unsigned int min_channel,
unsigned int max_channel);
static inline struct mite_channel *mite_request_channel(struct mite *mite,
struct mite_ring *ring)
{
return mite_request_channel_in_range(mite, ring, 0,
mite->num_channels - 1);
}
void mite_release_channel(struct mite_channel *mite_chan);
void mite_dma_arm(struct mite_channel *mite_chan);
void mite_dma_disarm(struct mite_channel *mite_chan);
void mite_sync_dma(struct mite_channel *mite_chan, struct comedi_subdevice *s);
@ -85,6 +71,13 @@ 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);
struct mite_channel *mite_request_channel_in_range(struct mite *,
struct mite_ring *,
unsigned int min_channel,
unsigned int max_channel);
struct mite_channel *mite_request_channel(struct mite *, struct mite_ring *);
void mite_release_channel(struct mite_channel *);
int mite_init_ring_descriptors(struct mite_ring *, struct comedi_subdevice *,
unsigned int nbytes);
int mite_buf_change(struct mite_ring *, struct comedi_subdevice *);