summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorSerge Semin <Sergey.Semin@baikalelectronics.ru>2020-07-23 03:58:43 +0300
committerVinod Koul <vkoul@kernel.org>2020-07-27 14:30:55 +0530
commit3b6d694eb3eebd86ec44a119e730943ac8e03a6b (patch)
tree7778f9828085cdfabd8b546fbbe93d29915d9c2c
parentb1b40b8fe7e8fb26e33bad1766ce322d2c63a6c7 (diff)
downloadlinux-stable-3b6d694eb3eebd86ec44a119e730943ac8e03a6b.tar.gz
linux-stable-3b6d694eb3eebd86ec44a119e730943ac8e03a6b.tar.bz2
linux-stable-3b6d694eb3eebd86ec44a119e730943ac8e03a6b.zip
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.c10
-rw-r--r--include/linux/dmaengine.h4
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);