From mboxrd@z Thu Jan  1 00:00:00 1970
From: will.deacon@arm.com (Will Deacon)
Date: Fri, 23 Nov 2018 18:27:16 +0000
Subject: [PATCH 06/10] swiotlb: use swiotlb_map_page in
 swiotlb_map_sg_attrs
In-Reply-To: <20181120092516.GC7270@lst.de>
References: <20181008080246.20543-1-hch@lst.de>
 <20181008080246.20543-7-hch@lst.de>
 <CANcMJZAzrxA9LGNvP-epv2DwsUacEM_hcgA1n5gmaPuWRJG4iw@mail.gmail.com>
 <20181109074955.GA27489@lst.de>
 <CALAqxLVSDkv4faF3ta_ue9AA9s8B=-8cAMxC_sow+wZYtrfxeQ@mail.gmail.com>
 <20181114141311.GA26677@lst.de> <20181114161239.GA29462@lst.de>
 <CALAqxLVMW2sYkaQvggZ-LhvkzpuF2rssQJ4thZkkAkROk=wVVw@mail.gmail.com>
 <20181120092516.GC7270@lst.de>
Message-ID: <20181123182715.GA21183@arm.com>
To: linux-arm-kernel@lists.infradead.org
List-Id: linux-arm-kernel.lists.infradead.org

Hi John,

On Tue, Nov 20, 2018 at 10:25:16AM +0100, Christoph Hellwig wrote:
> On Mon, Nov 19, 2018 at 03:22:13PM -0800, John Stultz wrote:
> > > +               sg->dma_address = dma_addr;
> > >                 sg_dma_len(sg) = sg->length;
> > >         }
> > 
> > I know Robin has already replied with more detailed info, but just to
> > close the loop as I'm finally home, applying this patch didn't seem to
> > help with the IO hangs I'm seeing w/ HiKey960.
> 
> If Robins observation is right this should fix the problem for you:

Please could you give this diff a try and let us know whether the problem
persists with your board?

Thanks,

Will

> diff --git a/include/linux/dma-direct.h b/include/linux/dma-direct.h
> index bd73e7a91410..1833f0c1fba0 100644
> --- a/include/linux/dma-direct.h
> +++ b/include/linux/dma-direct.h
> @@ -5,7 +5,7 @@
>  #include <linux/dma-mapping.h>
>  #include <linux/mem_encrypt.h>
>  
> -#define DIRECT_MAPPING_ERROR		0
> +#define DIRECT_MAPPING_ERROR		(~(dma_addr_t)0x0)
>  
>  #ifdef CONFIG_ARCH_HAS_PHYS_TO_DMA
>  #include <asm/dma-direct.h>