Messages in this thread | | | Date | Tue, 30 Aug 2022 13:21:37 +0100 | Subject | Re: [PATCH v2 5/4] ARM: footbridge: remove custom DMA address handling | From | Robin Murphy <> |
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On 2022-08-25 21:15, Arnd Bergmann wrote: [...] > diff --git a/arch/arm/mach-footbridge/dc21285.c b/arch/arm/mach-footbridge/dc21285.c > index 372600bc15c8..f8920d0010de 100644 > --- a/arch/arm/mach-footbridge/dc21285.c > +++ b/arch/arm/mach-footbridge/dc21285.c > @@ -5,6 +5,7 @@ > * Copyright (C) 1998-2001 Russell King > * Copyright (C) 1998-2000 Phil Blundell > */ > +#include <linux/dma-map-ops.h> > #include <linux/kernel.h> > #include <linux/pci.h> > #include <linux/interrupt.h> > @@ -241,6 +242,22 @@ static irqreturn_t dc21285_parity_irq(int irq, void *dev_id) > return IRQ_HANDLED; > } > > +static int dc21285_pci_bus_notifier(struct notifier_block *nb, > + unsigned long action, > + void *data) > +{ > + if (action != BUS_NOTIFY_ADD_DEVICE) > + return NOTIFY_DONE; > + > + dma_direct_set_offset(data, PHYS_OFFSET, BUS_OFFSET, SZ_256M);
FWIW I've always had it in mind that for this kind of special case the platform could just statically allocate the dma_range_map and assign it to all devices. However in practice that needs some kfree_const() tweaks in the driver core, which I'm sure are out-of-scope for this series, so I'm mostly flagging this up to help myself remember that it might be worth doing a dma_direct_set_offset() cleanup sweep soon.
As-is the patch at least makes things a lot clearer, and presumably there aren't likely to be enough PCI devices for the extra allocations to have noticeable impact in the meantime.
Cheers, Robin.
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