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@xxxxxxxxxxx> --- Already sent few weeks ago. No change since https://lore.kernel.org/lkml/20220117100300.14150-1-amelie.delaunay@xxxxxxxxxxx/ --- drivers/dma/stm32-mdma.c | 21 ++++++++++++++++++++- 1 file changed, 20 insertions(+), 1 deletion(-) diff --git a/drivers/dma/stm32-mdma.c b/drivers/dma/stm32-mdma.c index 6f57ff0e7b37..95e5831e490a 100644 --- a/drivers/dma/stm32-mdma.c +++ b/drivers/dma/stm32-mdma.c @@ -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); } -- 2.25.1
