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Subject[PATCH v3 4/5] dmaengine: stm32-dma: Add support for STM32 DMAMUX
Date
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.madianga@gmail.com>
Signed-off-by: Pierre-Yves MORDRET <pierre-yves.mordret@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
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