@@ -192,6 +192,7 @@ struct rcar_dmac_chan {
* @iomem: remapped I/O memory base
* @n_channels: number of available channels
* @channels: array of DMAC channels
+ * @channels_mask: bitfield of which DMA channels are managed by this driver
* @modules: bitmask of client modules in use
*/
struct rcar_dmac {
@@ -202,6 +203,7 @@ struct rcar_dmac {
unsigned int n_channels;
struct rcar_dmac_chan *channels;
+ unsigned int channels_mask;
DECLARE_BITMAP(modules, 256);
};
@@ -438,7 +440,7 @@ static int rcar_dmac_init(struct rcar_dmac *dmac)
u16 dmaor;
/* Clear all channels and enable the DMAC globally. */
- rcar_dmac_write(dmac, RCAR_DMACHCLR, GENMASK(dmac->n_channels - 1, 0));
+ rcar_dmac_write(dmac, RCAR_DMACHCLR, dmac->channels_mask);
rcar_dmac_write(dmac, RCAR_DMAOR,
RCAR_DMAOR_PRI_FIXED | RCAR_DMAOR_DME);
@@ -814,6 +816,9 @@ static void rcar_dmac_stop_all_chan(struct rcar_dmac *dmac)
for (i = 0; i < dmac->n_channels; ++i) {
struct rcar_dmac_chan *chan = &dmac->channels[i];
+ if (!(dmac->channels_mask & BIT(i)))
+ continue;
+
/* Stop and reinitialize the channel. */
spin_lock_irq(&chan->lock);
rcar_dmac_chan_halt(chan);
@@ -1776,6 +1781,8 @@ static int rcar_dmac_chan_probe(struct rcar_dmac *dmac,
return 0;
}
+#define RCAR_DMAC_MAX_CHANNELS 32
+
static int rcar_dmac_parse_of(struct device *dev, struct rcar_dmac *dmac)
{
struct device_node *np = dev->of_node;
@@ -1787,12 +1794,16 @@ static int rcar_dmac_parse_of(struct device *dev, struct rcar_dmac *dmac)
return ret;
}
- if (dmac->n_channels <= 0 || dmac->n_channels >= 100) {
+ /* The hardware and driver don't support more than 32 bits in CHCLR */
+ if (dmac->n_channels <= 0 ||
+ dmac->n_channels >= RCAR_DMAC_MAX_CHANNELS) {
dev_err(dev, "invalid number of channels %u\n",
dmac->n_channels);
return -EINVAL;
}
+ dmac->channels_mask = GENMASK(dmac->n_channels - 1, 0);
+
return 0;
}
@@ -1802,7 +1813,6 @@ static int rcar_dmac_probe(struct platform_device *pdev)
DMA_SLAVE_BUSWIDTH_2_BYTES | DMA_SLAVE_BUSWIDTH_4_BYTES |
DMA_SLAVE_BUSWIDTH_8_BYTES | DMA_SLAVE_BUSWIDTH_16_BYTES |
DMA_SLAVE_BUSWIDTH_32_BYTES | DMA_SLAVE_BUSWIDTH_64_BYTES;
- unsigned int channels_offset = 0;
struct dma_device *engine;
struct rcar_dmac *dmac;
struct resource *mem;
@@ -1831,10 +1841,8 @@ static int rcar_dmac_probe(struct platform_device *pdev)
* level we can't disable it selectively, so ignore channel 0 for now if
* the device is part of an IOMMU group.
*/
- if (device_iommu_mapped(&pdev->dev)) {
- dmac->n_channels--;
- channels_offset = 1;
- }
+ if (device_iommu_mapped(&pdev->dev))
+ dmac->channels_mask &= ~BIT(0);
dmac->channels = devm_kcalloc(&pdev->dev, dmac->n_channels,
sizeof(*dmac->channels), GFP_KERNEL);
@@ -1892,8 +1900,10 @@ static int rcar_dmac_probe(struct platform_device *pdev)
INIT_LIST_HEAD(&engine->channels);
for (i = 0; i < dmac->n_channels; ++i) {
- ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i],
- i + channels_offset);
+ if (!(dmac->channels_mask & BIT(i)))
+ continue;
+
+ ret = rcar_dmac_chan_probe(dmac, &dmac->channels[i], i);
if (ret < 0)
goto error;
}
The commit 20c169aceb45 ("dmaengine: rcar-dmac: clear pertinence number of channels") forgets to clear the last channel by DMACHCLR in rcar_dmac_init() (and doesn't need to clear the first channel) if iommu is mapped to the device. So, this patch fixes it by using "channels_mask" bitfield. Note that the hardware and driver don't support more than 32 bits in DMACHCLR register anyway, so this patch should reject more than 32 channels in rcar_dmac_parse_of(). Fixes: 20c169aceb459575 ("dmaengine: rcar-dmac: clear pertinence number of channels") Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com> Reviewed-by: Simon Horman <horms+renesas@verge.net.au> Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be> --- Changes from v1: - Rebase on v5.3-rc6. - Fix the subject and commit log. - Add a condition to reject >= 32 channels instead of >= 100. (I had mentioned adding a condition for it as a more one separate patch, but it seems to be odd, especially how to describe it as a fixed patch. So, I included the condition on this patch.) - Add Fixes tag. - Add Geert-san's Reviewed-by. https://patchwork.kernel.org/patch/11118637/ drivers/dma/sh/rcar-dmac.c | 28 +++++++++++++++++++--------- 1 file changed, 19 insertions(+), 9 deletions(-)