On Tue, Sep 15, 2020 at 07:41:22AM +0200, Christoph Hellwig wrote: > On Mon, Sep 14, 2020 at 05:01:47PM -0600, Mathieu Poirier wrote: > > [700 lines of the fullquote deleted..] > > > > + for (r = map; r->size; r++) > > > + num_ranges++; > > > + > > > + new_map = kmemdup(map, array_size(num_ranges + 1, sizeof(*map)), > > > + GFP_KERNEL); > > > + if (!new_map) > > > + return -ENOMEM; > > > + to->dma_range_map = new_map; > > > + return 0; > > > +} > > > + > > > > This patch seemed Ok to me but it broke the stm32 remoteproc implementation. When > > I tested things out function dma_coerce_mask_and_cohenrent() returns -5 and the > > rest of the initialisation fails. I isolated things to function dma_to_pfn() > > [2]. In the original implementation __bus_to_pfn() returns 0xfffff and > > dev->dma_pfn_offset is equal to 0x38000. As such the function returns 0x137fff > > and dma_supported() a non-zero value[3]. > > > > With this set function dma_to_pfn() received a face lift. Function > > __bus_to_pfn() still returns 0xfffff but translate_dma_to_phys() returns 0, > > which forces dma_supported() to also return 0 and that is where the -5 (-EIO) > > comes from. > > > > Taking a futher look at translate_dma_to_phy(), @dma_addr never falls within the > > bus_dma_region ranges and returns 0. > > > > I'm suspecting an initialisation problem and if it occurred here, it will > > likely show up elsewhere. > > Can you try this incremental patch? > > diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h > index 088c97181ab146..c6b21acba7a459 100644 > --- a/include/linux/dma-direct.h > +++ b/include/linux/dma-direct.h > @@ -46,7 +46,7 @@ static inline phys_addr_t translate_dma_to_phys(struct device *dev, > if (dma_addr >= m->dma_start && dma_addr - m->dma_start < m->size) > return (phys_addr_t)dma_addr + m->offset; > > - return 0; > + return (phys_addr_t)-1; That did the trick - the stm32 platform driver's probe() function completes and the remote processor is operatinal. That being said the value returned by function dma_to_pfn() is 0x137fff in the original code and 0xfffff with your patches applied. Thanks, Mathieu > } > > #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
