Commit ec834f1c authored by Amelie Delaunay's avatar Amelie Delaunay Committed by Vinod Koul
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dmaengine: stm32-mdma: check the channel availability (secure or not) 



STM32_MDMA_CCR bit[8] is used to enable Secure Mode (SM). If this bit is
set, it means that all the channel registers are write-protected. So the
channel is not available for Linux use.

Add stm32_mdma_filter_fn() callback filter and give it to
__dma_request_chan (instead of dma_get_any_slave_channel()), to exclude the
channel if it is marked Secure.

Signed-off-by: default avatarAmelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20220330103645.99969-1-amelie.delaunay@foss.st.com


Signed-off-by: default avatarVinod Koul <vkoul@kernel.org>
parent 10598931

drivers/dma/stm32-mdma.c

+20 −1
Original line number Diff line number Diff line
@@ -73,6 +73,7 @@ 
#define STM32_MDMA_CCR_WEX		BIT(14)

#define STM32_MDMA_CCR_HEX		BIT(13)

#define STM32_MDMA_CCR_BEX		BIT(12)

#define STM32_MDMA_CCR_SM		BIT(8)

#define STM32_MDMA_CCR_PL_MASK		GENMASK(7, 6)

#define STM32_MDMA_CCR_PL(n)		FIELD_PREP(STM32_MDMA_CCR_PL_MASK, (n))

#define STM32_MDMA_CCR_TCIE		BIT(5)
@@ -248,6 +249,7 @@ struct stm32_mdma_device { 
	u32 nr_channels;

	u32 nr_requests;

	u32 nr_ahb_addr_masks;

	u32 chan_reserved;

	struct stm32_mdma_chan chan[STM32_MDMA_MAX_CHANNELS];

	u32 ahb_addr_masks[];

};
@@ -1456,10 +1458,23 @@ static void stm32_mdma_free_chan_resources(struct dma_chan *c) 
	chan->desc_pool = NULL;

}



static bool stm32_mdma_filter_fn(struct dma_chan *c, void *fn_param)

{

	struct stm32_mdma_chan *chan = to_stm32_mdma_chan(c);

	struct stm32_mdma_device *dmadev = stm32_mdma_get_dev(chan);



	/* Check if chan is marked Secure */

	if (dmadev->chan_reserved & BIT(chan->id))

		return false;



	return true;

}



static struct dma_chan *stm32_mdma_of_xlate(struct of_phandle_args *dma_spec,

					    struct of_dma *ofdma)

{

	struct stm32_mdma_device *dmadev = ofdma->of_dma_data;

	dma_cap_mask_t mask = dmadev->ddev.cap_mask;

	struct stm32_mdma_chan *chan;

	struct dma_chan *c;

	struct stm32_mdma_chan_config config;
@@ -1485,7 +1500,7 @@ static struct dma_chan *stm32_mdma_of_xlate(struct of_phandle_args *dma_spec, 
		return NULL;

	}



	c = dma_get_any_slave_channel(&dmadev->ddev);

	c = __dma_request_channel(&mask, stm32_mdma_filter_fn, &config, ofdma->of_node);

	if (!c) {

		dev_err(mdma2dev(dmadev), "No more channels available\n");

		return NULL;
@@ -1615,6 +1630,10 @@ static int stm32_mdma_probe(struct platform_device *pdev) 
	for (i = 0; i < dmadev->nr_channels; i++) {

		chan = &dmadev->chan[i];

		chan->id = i;



		if (stm32_mdma_read(dmadev, STM32_MDMA_CCR(i)) & STM32_MDMA_CCR_SM)

			dmadev->chan_reserved |= BIT(i);



		chan->vchan.desc_free = stm32_mdma_desc_free;

		vchan_init(&chan->vchan, dd);

	}