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dmatest: convert to dma_request_channel 

Replace the client registration infrastructure with a custom loop to
poll for channels.  Once dma_request_channel returns NULL stop asking
for channels.  A userspace side effect of this change if that loading
the dmatest module before loading a dma driver will result in no
channels being found, previously dmatest would get a callback.  To
facilitate testing in the built-in case dmatest_init is marked as a
late_initcall.  Another side effect is that channels under test can not
be used for any other purpose.

Cc: Haavard Skinnemoen <haavard.skinnemoen@atmel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
This commit is contained in:
Dan Williams 2009-01-06 11:38:15 -07:00
parent 59b5ec2144
commit 33df8ca068
2 changed files with 49 additions and 72 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

115
drivers/dma/dmatest.c
View File

@ -35,7 +35,7 @@ MODULE_PARM_DESC(threads_per_chan,
static unsigned int max_channels;
module_param(max_channels, uint, S_IRUGO);
MODULE_PARM_DESC(nr_channels,
MODULE_PARM_DESC(max_channels,
"Maximum number of channels to use (default: all)");
/*
@ -71,7 +71,7 @@ struct dmatest_chan {
/*
* These are protected by dma_list_mutex since they're only used by
* the DMA client event callback
* the DMA filter function callback
*/
static LIST_HEAD(dmatest_channels);
static unsigned int nr_channels;
@ -317,21 +317,16 @@ static void dmatest_cleanup_channel(struct dmatest_chan *dtc)
kfree(dtc);
}
static enum dma_state_client dmatest_add_channel(struct dma_chan *chan)
static int dmatest_add_channel(struct dma_chan *chan)
{
struct dmatest_chan *dtc;
struct dmatest_thread *thread;
unsigned int i;
/* Have we already been told about this channel? */
list_for_each_entry(dtc, &dmatest_channels, node)
if (dtc->chan == chan)
return DMA_DUP;
dtc = kmalloc(sizeof(struct dmatest_chan), GFP_KERNEL);
if (!dtc) {
pr_warning("dmatest: No memory for %s\n", dev_name(&chan->dev));
return DMA_NAK;
return -ENOMEM;
}
dtc->chan = chan;
@ -365,81 +360,57 @@ static enum dma_state_client dmatest_add_channel(struct dma_chan *chan)
list_add_tail(&dtc->node, &dmatest_channels);
nr_channels++;
return DMA_ACK;
return 0;
}
static enum dma_state_client dmatest_remove_channel(struct dma_chan *chan)
static enum dma_state_client filter(struct dma_chan *chan, void *param)
{
struct dmatest_chan *dtc, *_dtc;
list_for_each_entry_safe(dtc, _dtc, &dmatest_channels, node) {
if (dtc->chan == chan) {
list_del(&dtc->node);
dmatest_cleanup_channel(dtc);
pr_debug("dmatest: lost channel %s\n",
dev_name(&chan->dev));
return DMA_ACK;
}
}
return DMA_DUP;
if (!dmatest_match_channel(chan) || !dmatest_match_device(chan->device))
return DMA_DUP;
else
return DMA_ACK;
}
/*
* Start testing threads as new channels are assigned to us, and kill
* them when the channels go away.
*
* When we unregister the client, all channels are removed so this
* will also take care of cleaning things up when the module is
* unloaded.
*/
static enum dma_state_client
dmatest_event(struct dma_client *client, struct dma_chan *chan,
enum dma_state state)
{
enum dma_state_client ack = DMA_NAK;
switch (state) {
case DMA_RESOURCE_AVAILABLE:
if (!dmatest_match_channel(chan)
|| !dmatest_match_device(chan->device))
ack = DMA_DUP;
else if (max_channels && nr_channels >= max_channels)
ack = DMA_NAK;
else
ack = dmatest_add_channel(chan);
break;
case DMA_RESOURCE_REMOVED:
ack = dmatest_remove_channel(chan);
break;
default:
pr_info("dmatest: Unhandled event %u (%s)\n",
state, dev_name(&chan->dev));
break;
}
return ack;
}
static struct dma_client dmatest_client = {
.event_callback = dmatest_event,
};
static int __init dmatest_init(void)
{
dma_cap_set(DMA_MEMCPY, dmatest_client.cap_mask);
dma_async_client_register(&dmatest_client);
dma_async_client_chan_request(&dmatest_client);
dma_cap_mask_t mask;
struct dma_chan *chan;
int err = 0;
return 0;
dma_cap_zero(mask);
dma_cap_set(DMA_MEMCPY, mask);
for (;;) {
chan = dma_request_channel(mask, filter, NULL);
if (chan) {
err = dmatest_add_channel(chan);
if (err == 0)
continue;
else {
dma_release_channel(chan);
break; /* add_channel failed, punt */
}
} else
break; /* no more channels available */
if (max_channels && nr_channels >= max_channels)
break; /* we have all we need */
}
return err;
}
module_init(dmatest_init);
/* when compiled-in wait for drivers to load first */
late_initcall(dmatest_init);
static void __exit dmatest_exit(void)
{
dma_async_client_unregister(&dmatest_client);
struct dmatest_chan *dtc, *_dtc;
list_for_each_entry_safe(dtc, _dtc, &dmatest_channels, node) {
list_del(&dtc->node);
dmatest_cleanup_channel(dtc);
pr_debug("dmatest: dropped channel %s\n",
dev_name(&dtc->chan->dev));
dma_release_channel(dtc->chan);
}
}
module_exit(dmatest_exit);

6
include/linux/dmaengine.h
View File

@ -400,6 +400,12 @@ __dma_cap_set(enum dma_transaction_type tx_type, dma_cap_mask_t *dstp)
set_bit(tx_type, dstp->bits);
}
#define dma_cap_zero(mask) __dma_cap_zero(&(mask))
static inline void __dma_cap_zero(dma_cap_mask_t *dstp)
{
bitmap_zero(dstp->bits, DMA_TX_TYPE_END);
}
#define dma_has_cap(tx, mask) __dma_has_cap((tx), &(mask))
static inline int
__dma_has_cap(enum dma_transaction_type tx_type, dma_cap_mask_t *srcp)