[PATCH v3 4/5] dmaengine: stm32-dma: Add support for STM32 DMAMUX

[Pierre-Yves MORDRET]

This patch adds support for STM32 DMAMUX.
When the STM32 DMA controller is behind a STM32 DMAMUX the request line
number has not to be handled by DMA but DMAMUX.

Signed-off-by: M'boumba Cedric Madianga <cedric.madia...@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mord...@st.com>
---
 Version history:
    V3:
        * None
    v2:
        * Use DMAMUX Configuration API's
        * DMAXMUX(if used) provides ChannelID
---
---
 drivers/dma/stm32-dma.c | 44 +++++++++++++++++++++++++++++++-------------
 1 file changed, 31 insertions(+), 13 deletions(-)

diff --git a/drivers/dma/stm32-dma.c b/drivers/dma/stm32-dma.c
index 786fc8f..a9e5884 100644
--- a/drivers/dma/stm32-dma.c
+++ b/drivers/dma/stm32-dma.c
@@ -13,6 +13,7 @@
 #include <linux/delay.h>
 #include <linux/dmaengine.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma/stm32-dmamux.h>
 #include <linux/err.h>
 #include <linux/init.h>
 #include <linux/jiffies.h>
@@ -179,6 +180,7 @@ struct stm32_dma_device {
        struct clk *clk;
        struct reset_control *rst;
        bool mem2mem;
+       bool dmamux;
        struct stm32_dma_chan chan[STM32_DMA_MAX_CHANNELS];
 };
 
@@ -272,12 +274,18 @@ static int stm32_dma_slave_config(struct dma_chan *c,
                                  struct dma_slave_config *config)
 {
        struct stm32_dma_chan *chan = to_stm32_dma_chan(c);
+       int ret = 0;
 
        memcpy(&chan->dma_sconfig, config, sizeof(*config));
 
-       chan->config_init = true;
+       if (c->router)
+               ret = stm32_dmamux_set_config(c->router->dev, c->route_data,
+                                             c->chan_id);
 
-       return 0;
+       if (!ret)
+               chan->config_init = true;
+
+       return ret;
 }
 
 static u32 stm32_dma_irq_status(struct stm32_dma_chan *chan)
@@ -998,18 +1006,26 @@ static struct dma_chan *stm32_dma_of_xlate(struct 
of_phandle_args *dma_spec,
        cfg.stream_config = dma_spec->args[2];
        cfg.threshold = dma_spec->args[3];
 
-       if ((cfg.channel_id >= STM32_DMA_MAX_CHANNELS) ||
-           (cfg.request_line >= STM32_DMA_MAX_REQUEST_ID)) {
-               dev_err(dev, "Bad channel and/or request id\n");
-               return NULL;
-       }
-
-       chan = &dmadev->chan[cfg.channel_id];
+       if (dmadev->dmamux) {
+               c = dma_get_any_slave_channel(&dmadev->ddev);
+               if (!c) {
+                       dev_err(dev, "No more channel avalaible\n");
+                       return NULL;
+               }
+               chan = &dmadev->chan[c->chan_id];
+       } else {
+               if ((cfg.channel_id >= STM32_DMA_MAX_CHANNELS) ||
+                   (cfg.request_line >= STM32_DMA_MAX_REQUEST_ID)) {
+                       dev_err(dev, "Bad channel and/or request id\n");
+                       return NULL;
+               }
 
-       c = dma_get_slave_channel(&chan->vchan.chan);
-       if (!c) {
-               dev_err(dev, "No more channels available\n");
-               return NULL;
+               chan = &dmadev->chan[cfg.channel_id];
+               c = dma_get_slave_channel(&chan->vchan.chan);
+               if (!c) {
+                       dev_err(dev, "No more channel avalaible\n");
+                       return NULL;
+               }
        }
 
        stm32_dma_set_config(chan, &cfg);
@@ -1058,6 +1074,8 @@ static int stm32_dma_probe(struct platform_device *pdev)
        dmadev->mem2mem = of_property_read_bool(pdev->dev.of_node,
                                                "st,mem2mem");
 
+       dmadev->dmamux = of_property_read_bool(pdev->dev.of_node, "st,dmamux");
+
        dmadev->rst = devm_reset_control_get(&pdev->dev, NULL);
        if (!IS_ERR(dmadev->rst)) {
                reset_control_assert(dmadev->rst);
-- 
2.7.4