On Thursday 21 April 2016 12:04:20 Peter Griffin wrote:
> This patch adds support for the Flexible Direct Memory Access (FDMA) core
> driver. The FDMA is a slim core CPU with a dedicated firmware.
> It is a general purpose DMA controller capable of supporting 16
> independent DMA channels. Data moves maybe from memory to memory
> or between memory and paced latency critical real time targets and it
> is found on al STi based chipsets.
>
> Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
> Signed-off-by: Peter Griffin <peter.griffin@xxxxxxxxxx>
> ---
> drivers/dma/Kconfig | 12 +
> drivers/dma/Makefile | 1 +
> drivers/dma/st_fdma.c | 967 ++++++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 980 insertions(+)
> create mode 100644 drivers/dma/st_fdma.c
>
> diff --git a/drivers/dma/Kconfig b/drivers/dma/Kconfig
> index d96d87c..5910c4f 100644
> --- a/drivers/dma/Kconfig
> +++ b/drivers/dma/Kconfig
> @@ -527,6 +527,18 @@ config ZX_DMA
> help
> Support the DMA engine for ZTE ZX296702 platform devices.
>
> +config ST_FDMA
> + tristate "ST FDMA dmaengine support"
> + depends on ARCH_STI
Try to ensure that the driver builds on x86 (possibly adding
further dependencies if needed), then make this
depends on ARCH_STI || COMPILE_TEST
to get better build coverage.
> +static struct dma_chan *st_fdma_of_xlate(struct of_phandle_args *dma_spec,
> + struct of_dma *ofdma)
> +{
> + struct st_fdma_dev *fdev = ofdma->of_dma_data;
> + struct st_fdma_cfg cfg;
> +
> + if (dma_spec->args_count < 1)
> + return NULL;
> +
> + cfg.of_node = dma_spec->np;
> + cfg.req_line = dma_spec->args[0];
> + cfg.req_ctrl = 0;
> + cfg.type = ST_FDMA_TYPE_FREE_RUN;
> +
> + if (dma_spec->args_count > 1)
> + cfg.req_ctrl = dma_spec->args[1] & REQ_CTRL_CFG_MASK;
> +
> + if (dma_spec->args_count > 2)
> + cfg.type = dma_spec->args[2];
> +
> + dev_dbg(fdev->dev, "xlate req_line:%d type:%d req_ctrl:%#lx\n",
> + cfg.req_line, cfg.type, cfg.req_ctrl);
> +
> + return dma_request_channel(fdev->dma_device.cap_mask,
> + st_fdma_filter_fn, &cfg);
> +}
No need to look at all DMA channels in the system here with
dma_request_channel(). Just call dma_get_any_slave_channel()
to get the first available channel for this engine, then
set the configuration right in that channel data while parsing
the DT properties.
Arnd
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