The BCM2835 DMA driver deletes a channel from a list upon termination
without having added it to a list first. Moreover that operation is
protected by a spinlock which isn't taken anywhere else. These appear
to be remnants of an older version of the driver which accidentally
got mainlined. Remove the dead code.
While at it remove an outdated comment claiming the driver only supports
cyclic transactions. The driver has been supporting other transaction
types for more than two years.
Signed-off-by: Lukas Wunner <lukas@xxxxxxxxx>
Cc: Frank Pavlic <f.pavlic@xxxxxxxxx>
Cc: Martin Sperl <kernel@xxxxxxxxxxxxxxxx>
Cc: Florian Meier <florian.meier@xxxxxxxx>
---
drivers/dma/bcm2835-dma.c | 13 -------------
1 file changed, 13 deletions(-)
diff --git a/drivers/dma/bcm2835-dma.c b/drivers/dma/bcm2835-dma.c
index e424e232a3d0..633be2ee7f33 100644
--- a/drivers/dma/bcm2835-dma.c
+++ b/drivers/dma/bcm2835-dma.c
@@ -2,9 +2,6 @@
/*
* BCM2835 DMA engine support
*
- * This driver only supports cyclic DMA transfers
- * as needed for the I2S module.
- *
* Author: Florian Meier <florian.meier@xxxxxxxx>
* Copyright 2013
*
@@ -42,7 +39,6 @@
struct bcm2835_dmadev {
struct dma_device ddev;
- spinlock_t lock;
void __iomem *base;
struct device_dma_parameters dma_parms;
};
@@ -64,7 +60,6 @@ struct bcm2835_cb_entry {
struct bcm2835_chan {
struct virt_dma_chan vc;
- struct list_head node;
struct dma_slave_config cfg;
unsigned int dreq;
@@ -772,17 +767,11 @@ static int bcm2835_dma_slave_config(struct dma_chan *chan,
static int bcm2835_dma_terminate_all(struct dma_chan *chan)
{
struct bcm2835_chan *c = to_bcm2835_dma_chan(chan);
- struct bcm2835_dmadev *d = to_bcm2835_dma_dev(c->vc.chan.device);
unsigned long flags;
LIST_HEAD(head);
spin_lock_irqsave(&c->vc.lock, flags);
- /* Prevent this channel being scheduled */
- spin_lock(&d->lock);
- list_del_init(&c->node);
- spin_unlock(&d->lock);
-
/* stop DMA activity */
if (c->desc) {
vchan_terminate_vdesc(&c->desc->vd);
@@ -815,7 +804,6 @@ static int bcm2835_dma_chan_init(struct bcm2835_dmadev *d, int chan_id,
c->vc.desc_free = bcm2835_dma_desc_free;
vchan_init(&c->vc, &d->ddev);
- INIT_LIST_HEAD(&c->node);
c->chan_base = BCM2835_DMA_CHANIO(d->base, chan_id);
c->ch = chan_id;
@@ -918,7 +906,6 @@ static int bcm2835_dma_probe(struct platform_device *pdev)
od->ddev.residue_granularity = DMA_RESIDUE_GRANULARITY_BURST;
od->ddev.dev = &pdev->dev;
INIT_LIST_HEAD(&od->ddev.channels);
- spin_lock_init(&od->lock);
platform_set_drvdata(pdev, od);
--
2.19.2
