From: JeffyChen <jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
To: Randy Li <randy.li-TNX95d0MmH7DzftRWevZcw@public.gmane.org>,
tfiga-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org
Cc: Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>,
devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
jcliang-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org,
linux-rockchip-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
iommu-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org,
Heiko Stuebner <heiko-4mtYJXux2i+zQB+pC5nmwQ@public.gmane.org>
Subject: Re: [PATCH v4 08/13] iommu/rockchip: Control clocks needed to access the IOMMU
Date: Fri, 23 Feb 2018 18:36:49 +0800 [thread overview]
Message-ID: <5A8FEEC1.5040303@rock-chips.com> (raw)
In-Reply-To: <5A69B065.30501-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
Hi guys,
On 01/25/2018 06:24 PM, JeffyChen wrote:
> On 01/25/2018 05:42 PM, Randy Li wrote:
>>>>
>>>
>>> confirmed with Simon, there might be some iommus don't have a pd, and
>> We use the pd to control the NIU node(not on upstream), without a pd or
>> fake pd, none of the platform would work.
> after talked offline, it's possible to have iommu without pd in upstream
> kernel(and chromeos kernel), but on our internal kernel, the drivers
> would require pd(or fake pd) to reset modules when error happens.
>
> anyway, i think that means we do need clock control here.
found another reason to not depend on pd to control clocks.
currently we are using pd's pm_clk to keep clocks enabled during power
on. but in our pd binding doc, that is not needed:
- clocks (optional): phandles to clocks which need to be enabled while
power domain
switches state.
confirmed with Caesar, the pm_clk only required for some old
chips(rk3288 for example) due to hardware issue.
and i tested my chromebook kevin(rk3399), it works well after remove the
pm_clk:
+++ b/drivers/soc/rockchip/pm_domains.c
@@ -478,7 +478,6 @@ static int rockchip_pm_add_one_domain(struct
rockchip_pmu *pmu,
pd->genpd.power_on = rockchip_pd_power_on;
pd->genpd.attach_dev = rockchip_pd_attach_dev;
pd->genpd.detach_dev = rockchip_pd_detach_dev;
- pd->genpd.flags = GENPD_FLAG_PM_CLK;
will do more tests and send patch tomorrow.
>
>>> the CONFIG_PM could be disabled.I am hard to believe a modern platform
>>> can work without that.
>>>
>>> so it might be better to control clocks in iommu driver itself.
>> I won't
>> insist how the version of the iommu patch on the upstream, I
>> just post an idea here.
>> The version for kernel 4.4 is under internal review, the implementation
>> has been modified many times.
>>
>> I would suggest the managing clocks in pd is a more easy way and don't
>> need to spare those thing in two places.
next prev parent reply other threads:[~2018-02-23 10:36 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-18 11:52 [PATCH v4 00/13] iommu/rockchip: Use OF_IOMMU Jeffy Chen
2018-01-18 11:52 ` [PATCH v4 07/13] ARM: dts: rockchip: add clocks in vop iommu nodes Jeffy Chen
[not found] ` <20180118115251.5542-8-jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-19 3:23 ` Tomasz Figa
[not found] ` <CAAFQd5ACbV6Q2Jwze=hoG=13jSJKkYyDDs2HzvvdSK-RGK+w2g-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2018-01-19 4:55 ` JeffyChen
[not found] ` <5A617A5E.6070606-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-19 5:12 ` Tomasz Figa
[not found] ` <20180118115251.5542-1-jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-18 11:52 ` [PATCH v4 08/13] iommu/rockchip: Control clocks needed to access the IOMMU Jeffy Chen
[not found] ` <20180118115251.5542-9-jeffy.chen-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-18 12:27 ` Robin Murphy
2018-01-18 14:25 ` JeffyChen
[not found] ` <5A60AE41.2050101-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-22 1:18 ` Randy Li
[not found] ` <1f4b3c0d-1414-0012-a072-f4a11f432c21-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-22 2:15 ` JeffyChen
[not found] ` <5A654925.9020203-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-22 4:09 ` JeffyChen
[not found] ` <5A6563FA.8080602-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-24 9:51 ` Tomasz Figa
2018-01-25 9:42 ` Randy Li
[not found] ` <c05d4794-b76d-cfaa-d7ed-c44108117ee2-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-01-25 10:24 ` JeffyChen
[not found] ` <5A69B065.30501-TNX95d0MmH7DzftRWevZcw@public.gmane.org>
2018-02-23 10:36 ` JeffyChen [this message]
2018-01-18 12:44 ` [PATCH v4 00/13] iommu/rockchip: Use OF_IOMMU Joerg Roedel
2018-01-18 14:07 ` JeffyChen
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