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DMAENGINE: COH 901 318 rename confusing vars
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This fixes up the code with a lot of comments that make it readable,
rename things with opaque names like "data" into something more
appropriate, and remove some very confusing BUG() statements.

Signed-off-by: Linus Walleij <linus.walleij@stericsson.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
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Linus Walleij authored and Dan Williams committed Mar 24, 2010
1 parent 220bf99 commit cecd87d
Showing 1 changed file with 65 additions and 38 deletions.
103 changes: 65 additions & 38 deletions drivers/dma/coh901318.c
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Original file line number Diff line number Diff line change
Expand Up @@ -37,7 +37,7 @@ struct coh901318_desc {
struct list_head node;
struct scatterlist *sg;
unsigned int sg_len;
struct coh901318_lli *data;
struct coh901318_lli *lli;
enum dma_data_direction dir;
unsigned long flags;
};
Expand Down Expand Up @@ -283,7 +283,7 @@ static int coh901318_start(struct coh901318_chan *cohc)
}

static int coh901318_prep_linked_list(struct coh901318_chan *cohc,
struct coh901318_lli *data)
struct coh901318_lli *lli)
{
int channel = cohc->id;
void __iomem *virtbase = cohc->base->virtbase;
Expand All @@ -292,18 +292,18 @@ static int coh901318_prep_linked_list(struct coh901318_chan *cohc,
COH901318_CX_STAT_SPACING*channel) &
COH901318_CX_STAT_ACTIVE);

writel(data->src_addr,
writel(lli->src_addr,
virtbase + COH901318_CX_SRC_ADDR +
COH901318_CX_SRC_ADDR_SPACING * channel);

writel(data->dst_addr, virtbase +
writel(lli->dst_addr, virtbase +
COH901318_CX_DST_ADDR +
COH901318_CX_DST_ADDR_SPACING * channel);

writel(data->link_addr, virtbase + COH901318_CX_LNK_ADDR +
writel(lli->link_addr, virtbase + COH901318_CX_LNK_ADDR +
COH901318_CX_LNK_ADDR_SPACING * channel);

writel(data->control, virtbase + COH901318_CX_CTRL +
writel(lli->control, virtbase + COH901318_CX_CTRL +
COH901318_CX_CTRL_SPACING * channel);

return 0;
Expand Down Expand Up @@ -565,29 +565,30 @@ static int coh901318_config(struct coh901318_chan *cohc,
*/
static struct coh901318_desc *coh901318_queue_start(struct coh901318_chan *cohc)
{
struct coh901318_desc *cohd_que;
struct coh901318_desc *cohd;

/* start queued jobs, if any
/*
* start queued jobs, if any
* TODO: transmit all queued jobs in one go
*/
cohd_que = coh901318_first_queued(cohc);
cohd = coh901318_first_queued(cohc);

if (cohd_que != NULL) {
if (cohd != NULL) {
/* Remove from queue */
coh901318_desc_remove(cohd_que);
coh901318_desc_remove(cohd);
/* initiate DMA job */
cohc->busy = 1;

coh901318_desc_submit(cohc, cohd_que);
coh901318_desc_submit(cohc, cohd);

coh901318_prep_linked_list(cohc, cohd_que->data);
coh901318_prep_linked_list(cohc, cohd->lli);

/* start dma job */
/* start dma job on this channel */
coh901318_start(cohc);

}

return cohd_que;
return cohd;
}

/*
Expand Down Expand Up @@ -622,7 +623,7 @@ static void dma_tasklet(unsigned long data)
cohc->completed = cohd_fin->desc.cookie;

/* release the lli allocation and remove the descriptor */
coh901318_lli_free(&cohc->base->pool, &cohd_fin->data);
coh901318_lli_free(&cohc->base->pool, &cohd_fin->lli);

/* return desc to free-list */
coh901318_desc_remove(cohd_fin);
Expand Down Expand Up @@ -666,23 +667,44 @@ static void dma_tasklet(unsigned long data)
/* called from interrupt context */
static void dma_tc_handle(struct coh901318_chan *cohc)
{
BUG_ON(!cohc->allocated && (list_empty(&cohc->active) ||
list_empty(&cohc->queue)));

if (!cohc->allocated)
/*
* If the channel is not allocated, then we shouldn't have
* any TC interrupts on it.
*/
if (!cohc->allocated) {
dev_err(COHC_2_DEV(cohc), "spurious interrupt from "
"unallocated channel\n");
return;
}

spin_lock(&cohc->lock);

/*
* When we reach this point, at least one queue item
* should have been moved over from cohc->queue to
* cohc->active and run to completion, that is why we're
* getting a terminal count interrupt is it not?
* If you get this BUG() the most probable cause is that
* the individual nodes in the lli chain have IRQ enabled,
* so check your platform config for lli chain ctrl.
*/
BUG_ON(list_empty(&cohc->active));

cohc->nbr_active_done++;

/*
* This attempt to take a job from cohc->queue, put it
* into cohc->active and start it.
*/
if (coh901318_queue_start(cohc) == NULL)
cohc->busy = 0;

BUG_ON(list_empty(&cohc->active));

spin_unlock(&cohc->lock);

/*
* This tasklet will remove items from cohc->active
* and thus terminates them.
*/
if (cohc_chan_conf(cohc)->priority_high)
tasklet_hi_schedule(&cohc->tasklet);
else
Expand Down Expand Up @@ -870,7 +892,7 @@ static struct dma_async_tx_descriptor *
coh901318_prep_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
size_t size, unsigned long flags)
{
struct coh901318_lli *data;
struct coh901318_lli *lli;
struct coh901318_desc *cohd;
unsigned long flg;
struct coh901318_chan *cohc = to_coh901318_chan(chan);
Expand All @@ -892,23 +914,23 @@ coh901318_prep_memcpy(struct dma_chan *chan, dma_addr_t dest, dma_addr_t src,
if ((lli_len << MAX_DMA_PACKET_SIZE_SHIFT) < size)
lli_len++;

data = coh901318_lli_alloc(&cohc->base->pool, lli_len);
lli = coh901318_lli_alloc(&cohc->base->pool, lli_len);

if (data == NULL)
if (lli == NULL)
goto err;

ret = coh901318_lli_fill_memcpy(
&cohc->base->pool, data, src, size, dest,
&cohc->base->pool, lli, src, size, dest,
cohc_chan_param(cohc)->ctrl_lli_chained,
ctrl_last);
if (ret)
goto err;

COH_DBG(coh901318_list_print(cohc, data));
COH_DBG(coh901318_list_print(cohc, lli));

/* Pick a descriptor to handle this transfer */
cohd = coh901318_desc_get(cohc);
cohd->data = data;
cohd->lli = lli;
cohd->flags = flags;
cohd->desc.tx_submit = coh901318_tx_submit;

Expand All @@ -926,7 +948,7 @@ coh901318_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
unsigned long flags)
{
struct coh901318_chan *cohc = to_coh901318_chan(chan);
struct coh901318_lli *data;
struct coh901318_lli *lli;
struct coh901318_desc *cohd;
const struct coh901318_params *params;
struct scatterlist *sg;
Expand Down Expand Up @@ -999,13 +1021,13 @@ coh901318_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
}

pr_debug("Allocate %d lli:s for this transfer\n", len);
data = coh901318_lli_alloc(&cohc->base->pool, len);
lli = coh901318_lli_alloc(&cohc->base->pool, len);

if (data == NULL)
if (lli == NULL)
goto err_dma_alloc;

/* initiate allocated data list */
ret = coh901318_lli_fill_sg(&cohc->base->pool, data, sgl, sg_len,
/* initiate allocated lli list */
ret = coh901318_lli_fill_sg(&cohc->base->pool, lli, sgl, sg_len,
cohc_dev_addr(cohc),
ctrl_chained,
ctrl,
Expand All @@ -1014,14 +1036,14 @@ coh901318_prep_slave_sg(struct dma_chan *chan, struct scatterlist *sgl,
if (ret)
goto err_lli_fill;

COH_DBG(coh901318_list_print(cohc, data));
COH_DBG(coh901318_list_print(cohc, lli));

/* Pick a descriptor to handle this transfer */
cohd = coh901318_desc_get(cohc);
cohd->dir = direction;
cohd->flags = flags;
cohd->desc.tx_submit = coh901318_tx_submit;
cohd->data = data;
cohd->lli = lli;

spin_unlock_irqrestore(&cohc->lock, flg);

Expand Down Expand Up @@ -1065,7 +1087,12 @@ coh901318_issue_pending(struct dma_chan *chan)

spin_lock_irqsave(&cohc->lock, flags);

/* Busy means that pending jobs are already being processed */
/*
* Busy means that pending jobs are already being processed,
* and then there is no point in starting the queue: the
* terminal count interrupt on the channel will take the next
* job on the queue and execute it anyway.
*/
if (!cohc->busy)
coh901318_queue_start(cohc);

Expand Down Expand Up @@ -1099,7 +1126,7 @@ coh901318_terminate_all(struct dma_chan *chan)

while ((cohd = coh901318_first_active_get(cohc))) {
/* release the lli allocation*/
coh901318_lli_free(&cohc->base->pool, &cohd->data);
coh901318_lli_free(&cohc->base->pool, &cohd->lli);

/* return desc to free-list */
coh901318_desc_remove(cohd);
Expand All @@ -1108,7 +1135,7 @@ coh901318_terminate_all(struct dma_chan *chan)

while ((cohd = coh901318_first_queued(cohc))) {
/* release the lli allocation*/
coh901318_lli_free(&cohc->base->pool, &cohd->data);
coh901318_lli_free(&cohc->base->pool, &cohd->lli);

/* return desc to free-list */
coh901318_desc_remove(cohd);
Expand Down

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