From 4d8bde883bfba3e8dd3335f91b640e5a70ec0aa6 Mon Sep 17 00:00:00 2001 From: Robin Murphy Date: Mon, 23 Jul 2018 23:16:12 +0100 Subject: [PATCH] OF: Don't set default coherent DMA mask Now that we can track upstream DMA constraints properly with bus_dma_mask instead of trying (and failing) to maintain it in coherent_dma_mask, it doesn't make much sense for the firmware code to be touching the latter at all. It's merely papering over bugs wherein a driver has failed to call dma_set_coherent_mask() *and* the bus code has not initialised any default value. We don't really want to encourage more drivers coercing dma_mask so we'll continue to fix that up if necessary, but add a warning to help flush out any such buggy bus code that remains. Signed-off-by: Robin Murphy Acked-by: Ard Biesheuvel Signed-off-by: Christoph Hellwig --- drivers/of/device.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-) diff --git a/drivers/of/device.c b/drivers/of/device.c index 0d39633e8545..5957cd4fa262 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -127,20 +127,20 @@ int of_dma_configure(struct device *dev, struct device_node *np, bool force_dma) } /* - * Set default coherent_dma_mask to 32 bit. Drivers are expected to - * setup the correct supported mask. + * If @dev is expected to be DMA-capable then the bus code that created + * it should have initialised its dma_mask pointer by this point. For + * now, we'll continue the legacy behaviour of coercing it to the + * coherent mask if not, but we'll no longer do so quietly. */ - if (!dev->coherent_dma_mask) - dev->coherent_dma_mask = DMA_BIT_MASK(32); - /* - * Set it to coherent_dma_mask by default if the architecture - * code has not set it. - */ - if (!dev->dma_mask) + if (!dev->dma_mask) { + dev_warn(dev, "DMA mask not set\n"); dev->dma_mask = &dev->coherent_dma_mask; + } - if (!size) + if (!size && dev->coherent_dma_mask) size = max(dev->coherent_dma_mask, dev->coherent_dma_mask + 1); + else if (!size) + size = 1ULL << 32; dev->dma_pfn_offset = offset; -- 2.30.2