On Mon, Jan 21, 2019 at 11:11:21AM +0100, Rafał Miłecki wrote: > From: Rafał Miłecki <[email protected]> > > For bus devices to be fully usable it's required to set their DMA > parameters. > > For years it has been missing and remained unnoticed because of > mips_dma_alloc_coherent() silently handling the empty coherent_dma_mask. > Kernel 4.19 came with a lot of DMA changes and caused a regression on > the bcm47xx. Starting with the commit f8c55dc6e828 ("MIPS: use generic > dma noncoherent ops for simple noncoherent platforms") DMA coherent > allocations just fail. Example: > [ 1.114914] bgmac_bcma bcma0:2: Allocation of TX ring 0x200 failed > [ 1.121215] bgmac_bcma bcma0:2: Unable to alloc memory for DMA > [ 1.127626] bgmac_bcma: probe of bcma0:2 failed with error -12 > [ 1.133838] bgmac_bcma: Broadcom 47xx GBit MAC driver loaded > > This change fixes above regression in addition to the MIPS bcm47xx > commit 321c46b91550 ("MIPS: BCM47XX: Setup struct device for the SoC"). > > It also fixes another *old* GPIO regression caused by a parent pointing > to the NULL: > [ 0.157054] missing gpiochip .dev parent pointer > [ 0.157287] bcma: bus0: Error registering GPIO driver: -22 > introduced by the commit 74f4e0cc6108 ("bcma: switch GPIO portions to > use GPIOLIB_IRQCHIP"). > > Fixes: f8c55dc6e828 ("MIPS: use generic dma noncoherent ops for simple > noncoherent platforms") > Fixes: 74f4e0cc6108 ("bcma: switch GPIO portions to use GPIOLIB_IRQCHIP") > Cc: [email protected] > Cc: Christoph Hellwig <[email protected]> > Cc: Linus Walleij <[email protected]> > Signed-off-by: Rafał Miłecki <[email protected]> > --- > While this patch is a regression fix, it depends on a change present in > the wireless-drivers-next.git: > bcma: keep a direct pointer to the struct device > > That's why I suggest pushing it into the wireless-drivers-next.git and I > can take care of picking it for the [email protected] later. > > Another option would be cherry-picking commit 5a1c18b761dd ("bcma: keep > a direct pointer to the struct device") to the wireless-drivers.git but > I don't think it's a common practice. > --- > drivers/bcma/host_soc.c | 2 ++ > drivers/bcma/main.c | 6 +++++- > include/linux/bcma/bcma_soc.h | 1 + > 3 files changed, 8 insertions(+), 1 deletion(-) > > diff --git a/drivers/bcma/host_soc.c b/drivers/bcma/host_soc.c > index c8073b509a2b..1fdfb704f22d 100644 > --- a/drivers/bcma/host_soc.c > +++ b/drivers/bcma/host_soc.c > @@ -191,6 +191,8 @@ int __init bcma_host_soc_init(struct bcma_soc *soc) > struct bcma_bus *bus = &soc->bus; > int err; > > + bus->dev = soc->dev; > + > /* Scan bus and initialize it */ > err = bcma_bus_early_register(bus); > if (err) > diff --git a/drivers/bcma/main.c b/drivers/bcma/main.c > index 6535614a7dc1..433ca5e2ed2c 100644 > --- a/drivers/bcma/main.c > +++ b/drivers/bcma/main.c > @@ -236,12 +236,16 @@ EXPORT_SYMBOL(bcma_core_irq); > > void bcma_prepare_core(struct bcma_bus *bus, struct bcma_device *core) > { > + struct device *dev = &core->dev; > + > core->dev.release = bcma_release_core_dev; > core->dev.bus = &bcma_bus_type; > dev_set_name(&core->dev, "bcma%d:%d", bus->num, core->core_index); > core->dev.parent = bus->dev; > - if (bus->dev) > + if (bus->dev) { > bcma_of_fill_device(bus->dev, core); > + dma_coerce_mask_and_coherent(dev, bus->dev->coherent_dma_mask); > + }
I don't think this does the right thing for bcma devices behind PCI/PCIe, as those might need a IOMMU which relies on having a device it has properly enumerated to be passed into the DMA API. In other words: I think you need to change the layering so that the DMA API is always called on the underlying PCI/PCIe/platform device, not of the child bus.
