diff options
| author | Serge Semin <Sergey.Semin@baikalelectronics.ru> | 2020-07-23 03:58:43 +0300 |
|---|---|---|
| committer | Vinod Koul <vkoul@kernel.org> | 2020-07-27 12:00:55 +0300 |
| commit | 3b6d694eb3eebd86ec44a119e730943ac8e03a6b (patch) | |
| tree | 7778f9828085cdfabd8b546fbbe93d29915d9c2c | |
| parent | b1b40b8fe7e8fb26e33bad1766ce322d2c63a6c7 (diff) | |
| download | linux-3b6d694eb3eebd86ec44a119e730943ac8e03a6b.tar.xz | |
dmaengine: Introduce DMA-device device_caps callback
There are DMA devices (like ours version of Synopsys DW DMAC) which have
DMA capabilities non-uniformly redistributed between the device channels.
In order to provide a way of exposing the channel-specific parameters to
the DMA engine consumers, we introduce a new DMA-device callback. In case
if provided it gets called from the dma_get_slave_caps() method and is
able to override the generic DMA-device capabilities.
Signed-off-by: Serge Semin <Sergey.Semin@baikalelectronics.ru>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20200723005848.31907-6-Sergey.Semin@baikalelectronics.ru
Signed-off-by: Vinod Koul <vkoul@kernel.org>
| -rw-r--r-- | drivers/dma/dmaengine.c | 10 | ||||
| -rw-r--r-- | include/linux/dmaengine.h | 4 |
2 files changed, 14 insertions, 0 deletions
diff --git a/drivers/dma/dmaengine.c b/drivers/dma/dmaengine.c index 8177f78faeda..a53e71d2bbd4 100644 --- a/drivers/dma/dmaengine.c +++ b/drivers/dma/dmaengine.c @@ -601,6 +601,16 @@ int dma_get_slave_caps(struct dma_chan *chan, struct dma_slave_caps *caps) caps->cmd_resume = !!device->device_resume; caps->cmd_terminate = !!device->device_terminate_all; + /* + * DMA engine device might be configured with non-uniformly + * distributed slave capabilities per device channels. In this + * case the corresponding driver may provide the device_caps + * callback to override the generic capabilities with + * channel-specific ones. + */ + if (device->device_caps) + device->device_caps(chan, caps); + return 0; } EXPORT_SYMBOL_GPL(dma_get_slave_caps); diff --git a/include/linux/dmaengine.h b/include/linux/dmaengine.h index 4cbe09e66db2..d718671bfd25 100644 --- a/include/linux/dmaengine.h +++ b/include/linux/dmaengine.h @@ -801,6 +801,8 @@ struct dma_filter { * be called after period_len bytes have been transferred. * @device_prep_interleaved_dma: Transfer expression in a generic way. * @device_prep_dma_imm_data: DMA's 8 byte immediate data to the dst address + * @device_caps: May be used to override the generic DMA slave capabilities + * with per-channel specific ones * @device_config: Pushes a new configuration to a channel, return 0 or an error * code * @device_pause: Pauses any transfer happening on a channel. Returns @@ -901,6 +903,8 @@ struct dma_device { struct dma_chan *chan, dma_addr_t dst, u64 data, unsigned long flags); + void (*device_caps)(struct dma_chan *chan, + struct dma_slave_caps *caps); int (*device_config)(struct dma_chan *chan, struct dma_slave_config *config); int (*device_pause)(struct dma_chan *chan); |