On Mon, Aug 27, 2018 at 08:46:41AM -0700, Christoph Hellwig wrote: > > sparc: > > > > WARNING: CPU: 0 PID: 1 at ./include/linux/dma-mapping.h:516 > > esp_sbus_probe+0x408/0x6e8 > > WARNING: CPU: 0 PID: 1 at ./include/linux/dma-mapping.h:516 > > sparc_lance_probe_one+0x428/0x4f > > > > Missing initialization of coherent_dma_mask in the respective drivers. > > > > --- > > Each platform driver instantiated through a devicetree node now generates > > the following warning: > > > > esp ffd38e00: DMA mask not set > > > > It isn't a traceback so it may fly under the radar. There is nothing the > > drivers can do about it; the message is generated by the core before the > > driver probe function is called. No idea what a correct fix might be. > > Both of these should probably be fixed by something like the patch > below: > > --- > From 6294e0e330851ee06e66ab85b348f1d92d375d7a Mon Sep 17 00:00:00 2001 > From: Christoph Hellwig <h...@lst.de> > Date: Mon, 27 Aug 2018 17:23:24 +0200 > Subject: driver core: initialize a default DMA mask for platform device > > We still treat devices without a DMA mask as defaulting to 32-bits for > both mask, but a few releases ago we've started warning about such > cases, as they require special cases to work around this sloppyness. > Add a dma_mask field to struct platform_object so that we can initialize > the dma_mask pointer in struct device and initialize both masks to > 32-bits by default. Architectures can still override this in > arch_setup_pdev_archdata if needed. > > Note that the code looks a little odd with the various conditionals > because we have to support platform_device structures that are > statically allocated. > > Signed-off-by: Christoph Hellwig <h...@lst.de> > --- > drivers/base/platform.c | 15 +++++++++++++-- > include/linux/platform_device.h | 1 + > 2 files changed, 14 insertions(+), 2 deletions(-) > > diff --git a/drivers/base/platform.c b/drivers/base/platform.c > index dff82a3c2caa..baf4b06cf2d9 100644 > --- a/drivers/base/platform.c > +++ b/drivers/base/platform.c > @@ -225,6 +225,17 @@ struct platform_object { > char name[]; > }; > > +static void setup_pdev_archdata(struct platform_device *pdev) > +{ > + if (!pdev->dev.coherent_dma_mask) > + pdev->dev.coherent_dma_mask = DMA_BIT_MASK(32); > + if (!pdev->dma_mask) > + pdev->dma_mask = DMA_BIT_MASK(32); > + if (!pdev->dev.dma_mask) > + pdev->dev.dma_mask = &pdev->dma_mask;
When building sparc32 images, this results in the following error. drivers/base/platform.c: In function 'setup_pdev_archdata': drivers/base/platform.c:235:22: error: assignment from incompatible pointer type [-Werror=incompatible-pointer-types] pdev->dev.dma_mask = &pdev->dma_mask; pdev->dev.dma_mask is u64 *, pdev->dma_mask is dma_addr_t which in turn is either u32 or u64 depending on the architecture. > +++ b/include/linux/platform_device.h > @@ -25,6 +25,7 @@ struct platform_device { > int id; > bool id_auto; > struct device dev; > + dma_addr_t dma_mask; ... so this will have to be u64, or the pointer in struct device would have to be fixed. However, even changing the definition to u64 does not help: The warnings are still reported. This is because setup_pdev_archdata() is not called for any of the affected devices. That is kind of interesting since it means that arch_setup_pdev_archdata() won't be called for those devices either. Guenter