From: "Leizhen (ThunderTown)" <thunder.leizhen@huawei.com>
To: Arnd Bergmann <arnd@kernel.org>
Cc: Florian Fainelli <f.fainelli@gmail.com>,
Rob Herring <robh+dt@kernel.org>, Ray Jui <rjui@broadcom.com>,
Scott Branden <sbranden@broadcom.com>,
bcm-kernel-feedback-list <bcm-kernel-feedback-list@broadcom.com>,
Andy Gross <agross@kernel.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
devicetree <devicetree@vger.kernel.org>,
linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH v2 1/2] arm64: dts: broadcom: clear the warnings caused by empty dma-ranges
Date: Mon, 26 Oct 2020 10:21:08 +0800 [thread overview]
Message-ID: <07ab3bdd-dcb1-5a59-d813-f82451b3f028@huawei.com> (raw)
In-Reply-To: <CAK8P3a335TT1+bdHqB=FetPanXXfGv3dC7ZCkx+w+F3j00kj5A@mail.gmail.com>
On 2020/10/23 15:17, Arnd Bergmann wrote:
> On Sun, Oct 18, 2020 at 4:10 AM Leizhen (ThunderTown)
> <thunder.leizhen@huawei.com> wrote:
>> On 2020/10/17 3:27, Florian Fainelli wrote:
>>> On 10/16/20 11:23 AM, Arnd Bergmann wrote:
>>>> On Fri, Oct 16, 2020 at 6:48 PM Florian Fainelli <f.fainelli@gmail.com> wrote:
>>>>> On 10/16/20 4:01 AM, Arnd Bergmann wrote:
>>>>>> On Fri, Oct 16, 2020 at 11:09 AM Zhen Lei <thunder.leizhen@huawei.com> wrote:
>>>>>>>
>>>>>>> Suggested-by: Arnd Bergmann <arnd@arndb.de>
>>>>>>> Signed-off-by: Zhen Lei <thunder.leizhen@huawei.com>
>>>>>>
>>>>>> Acked-by: Arnd Bergmann <arnd@arndb.de>
>>>>>>
>>>>>> I see that at least the 'bcd' and 'xhci' devices in fact try to
>>>>>> use 64-bit DMA. It would be good to test this on actual
>>>>>> hardware to ensure that it works correctly when this is enabled.
>>>>>>
>>>>>> Ideally avoiding the swiotlb bounce buffering should only
>>>>>> make it faster here, but there are many chips on which
>>>>>> 64-bit DMA is broken in some form.
>>>>>
>>>>> Is this change really an improvement though? This 'usb' pseudo bus node
>>>>> could just keep being defined with #address-cells = <1> and #size-cells
>>>>> = <1> so as to satisfy the 'reg' definition however we could just adjust
>>>>> dma-ranges to indicate full 64-bit addressing capability. Would not that
>>>>> work?
>>>>
>>>> When #address-cells is '1', you cannot specify dma-ranges that
>>>> go beyond a 32-bit address range.
>>>
>>> Would not it be enough to remove the 'dma-ranges' property though? Sorry
>>> for being slow here.
>>
>> Remove the 'dma-ranges' property should also work. After all, it is equivalent
>> to the original empty dma-ranges scheme. In addition, since the IOMMU nodes are
>> defined, it should be enabled.
>
> Are you sure? I was expecting the IOMMU not to get used here since
> the devices do contain list an 'iommus' property.
OK，If the SMMU maybe disabled, then your proposal is necessary.
>
> Arnd
>
> .
>
next prev parent reply other threads:[~2020-10-26 2:21 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-16 9:08 [PATCH v2 0/2] eliminate two common errors reported by any yaml on arm64 Zhen Lei
2020-10-16 9:08 ` [PATCH v2 1/2] arm64: dts: broadcom: clear the warnings caused by empty dma-ranges Zhen Lei
[not found] ` <CAK8P3a2TSmsNSi-XFpT6AQ3jvVxJ1AW7Uf5tAo477wtwXZwUzg@mail.gmail.com>
2020-10-16 16:48 ` Florian Fainelli
[not found] ` <CAK8P3a13ywHh7igdfDSPQz9Bw8YAnKWFLKARkk2NL5u6=6yb=w@mail.gmail.com>
2020-10-16 19:27 ` Florian Fainelli
2020-10-18 2:10 ` Leizhen (ThunderTown)
[not found] ` <CAK8P3a335TT1+bdHqB=FetPanXXfGv3dC7ZCkx+w+F3j00kj5A@mail.gmail.com>
2020-10-26 2:21 ` Leizhen (ThunderTown) [this message]
2020-11-09 6:18 ` Leizhen (ThunderTown)
2020-11-09 17:28 ` Florian Fainelli
2020-11-09 17:56 ` Arnd Bergmann
2020-11-09 18:00 ` Florian Fainelli
2020-11-28 4:53 ` Florian Fainelli
2020-11-28 9:58 ` Arnd Bergmann
2020-12-14 19:09 ` Ray Jui
2020-12-14 19:46 ` Arnd Bergmann
2020-12-15 15:40 ` Florian Fainelli
[not found] ` <CACvutz9v+TBUbrCo3X-u5ebbs04nR0y0yQN3qWfSAyZVy9RM2g@mail.gmail.com>
2020-12-15 15:41 ` Florian Fainelli
2020-12-15 15:49 ` Arnd Bergmann
2021-01-12 18:28 ` Ray Jui
2021-01-12 20:40 ` Arnd Bergmann
2021-01-12 20:57 ` Ray Jui
2021-01-13 3:42 ` Bharat Gooty
2021-01-13 8:05 ` Arnd Bergmann
2021-01-13 16:55 ` Florian Fainelli
2021-01-13 17:45 ` Ray Jui
2020-10-16 9:08 ` [PATCH v2 2/2] arm64: dts: qcom: " Zhen Lei
2020-11-11 4:44 ` Bjorn Andersson
2020-12-29 20:15 ` [PATCH v2 0/2] eliminate two common errors reported by any yaml on arm64 patchwork-bot+linux-arm-msm
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