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dmaengine: stm32-mdma: check the channel availability (secure or not)

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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: Amelie Delaunay <amelie.delaunay@foss.st.com>
Link: https://lore.kernel.org/r/20220330103645.99969-1-amelie.delaunay@foss.st.com
Signed-off-by: Vinod Koul <vkoul@kernel.org>
This commit is contained in:
Amelie Delaunay 2022-03-30 12:36:45 +02:00 committed by Vinod Koul
parent 1059893114
commit ec834f1cc7
1 changed files with 20 additions and 1 deletions
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21
drivers/dma/stm32-mdma.c
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@ -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);
}