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Commit 33df8ca0 authored by Dan Williams's avatar Dan Williams
Browse files

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: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
parent 59b5ec21

drivers/dma/dmatest.c

+43 −72
Original line number Diff line number Diff line
@@ -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;

		}

	}



	if (!dmatest_match_channel(chan) || !dmatest_match_device(chan->device))

		return DMA_DUP;

}



/*

 * 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;

		return DMA_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;



	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 0;

	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);

include/linux/dmaengine.h

+6 −0
Original line number Diff line number Diff line
@@ -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)