diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index bb30a9aa54d3..c5fef57b5adf 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -1078,6 +1078,7 @@ static int __dma_async_device_channel_register(struct dma_device *device, struct dma_chan *chan, const char *name) { + unsigned int id; int rc; chan->local = alloc_percpu(typeof(*chan->local)); @@ -1089,11 +1090,13 @@ static int __dma_async_device_channel_register(struct dma_device *device, goto err_free_local; } - /* - * When the chan_id is a negative value, we are dynamically adding - * the channel. Otherwise we are static enumerating. - */ - chan->chan_id = ida_alloc(&device->chan_ida, GFP_KERNEL); + if (chan->chan_id & DMA_CHAN_ID_STATIC) { + id = chan->chan_id & ~DMA_CHAN_ID_STATIC; + chan->chan_id = ida_alloc_range(&device->chan_ida, id, id, + GFP_KERNEL); + } else { + chan->chan_id = ida_alloc(&device->chan_ida, GFP_KERNEL); + } if (chan->chan_id < 0) { pr_err("%s: unable to alloc ida for chan: %d\n", __func__, chan->chan_id); diff --git a/drivers/dma/dw-edma/dw-edma-core.c b/drivers/dma/dw-edma/dw-edma-core.c index e2eba6d72b53..4ed35e452d17 100644 --- a/drivers/dma/dw-edma/dw-edma-core.c +++ b/drivers/dma/dw-edma/dw-edma-core.c @@ -1119,6 +1119,7 @@ static int dw_edma_channel_setup(struct dw_edma *dw, u32 wr_alloc, u32 rd_alloc) &dw->chip->dt_region_rd[chan->id]; vchan_init(&chan->vc, dma); + dmaengine_set_static_chan_id(&chan->vc.chan, i); dw_edma_core_ch_config(chan); } diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index c3a49a33307c..0ada6fe66e80 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -377,6 +377,26 @@ struct dma_chan { void *private; }; +#define DMA_CHAN_ID_STATIC BIT(30) + +/** + * dmaengine_set_static_chan_id - request an exact DMA engine channel ID + * @chan: DMA channel + * @id: channel ID, unique within the DMA device + * + * Drivers may call this after initializing @chan and before registering its + * DMA device. The dmaengine core reserves @id from the device IDA instead of + * assigning the next available ID. + */ +static inline void dmaengine_set_static_chan_id(struct dma_chan *chan, + unsigned int id) +{ + if (WARN_ON_ONCE(id >= DMA_CHAN_ID_STATIC)) + return; + + chan->chan_id = DMA_CHAN_ID_STATIC | id; +} + /** * struct dma_chan_dev - relate sysfs device node to backing channel device * @chan: driver channel device