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From: Lokesh Vutla <lokeshvutla@ti.com>
To: Tero Kristo <t-kristo@ti.com>, Nishanth Menon <nm@ti.com>,
	Santosh Shilimkar <ssantosh@kernel.org>,
	Rob Herring <robh+dt@kernel.org>
Cc: Device Tree Mailing List <devicetree@vger.kernel.org>,
	Sekhar Nori <nsekhar@ti.com>,
	Linux ARM Mailing List <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH v3 2/5] dt-bindings: ti_sci_pm_domains: Add support for exclusive and shared access
Date: Wed, 10 Apr 2019 18:07:02 +0530	[thread overview]
Message-ID: <dfceed14-d88f-72cb-a647-0ce3fbea3ca5@ti.com> (raw)
In-Reply-To: <2087d79b-67b0-5ce4-bf2f-f659ef1a5494@ti.com>

Hi Tero,

On 10/04/19 1:34 PM, Tero Kristo wrote:
> On 10/04/2019 08:37, Lokesh Vutla wrote:
>> TISCI protocol supports for enabling the device either with exclusive
>> permissions for the requesting host or with sharing across the hosts.
>> There are certain devices which are exclusive to Linux context and
>> there are certain devices that are shared across different host contexts.
>> So add support for getting this information from DT by increasing
>> the power-domain cells to 2.
>>
>> Signed-off-by: Lokesh Vutla <lokeshvutla@ti.com>
>> ---
>>   .../devicetree/bindings/soc/ti/sci-pm-domain.txt      | 11 +++++++++--
>>   MAINTAINERS                                           |  1 +
>>   include/dt-bindings/soc/ti,sci_pm_domain.h            |  9 +++++++++
>>   3 files changed, 19 insertions(+), 2 deletions(-)
>>   create mode 100644 include/dt-bindings/soc/ti,sci_pm_domain.h
>>
>> diff --git a/Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt
>> b/Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt
>> index f7b00a7c0f68..f541d1f776a2 100644
>> --- a/Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt
>> +++ b/Documentation/devicetree/bindings/soc/ti/sci-pm-domain.txt
>> @@ -19,8 +19,15 @@ child of the pmmc node.
>>   Required Properties:
>>   --------------------
>>   - compatible: should be "ti,sci-pm-domain"
>> -- #power-domain-cells: Must be 1 so that an id can be provided in each
>> -               device node.
>> +- #power-domain-cells: Can be one of the following:
>> +            1: Containing the device id of each node
>> +            2: First entry should be device id
>> +               Second entry should be one of the floowing:
>> +               TI_SCI_PD_EXCLUSIVE: To allow device to be
>> +                        exclusively controlled by
>> +                        the requesting hosts.
>> +               TI_SCI_PD_SHARED: To allow device to be shared
>> +                         by multiple hosts.
> 
> One thing should be noted on this, the added flag is purely for software
> configuration, and is not telling us anything about the HW / firmware. Software

I does say about how firmware handles the requested device.

> can decide to have the flag either way and it will work. I just wonder if DT is
> the correct location to have something like this... Expect to have plenty of
> churn on this by people swapping the permissions around according to their
> use-case needs.

Do you have any other suggestion to handle shared devices across VMs?

Thanks and regards,
Lokesh

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  reply	other threads:[~2019-04-10 12:37 UTC|newest]

Thread overview: 17+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-10  5:37 [PATCH v3 0/5] soc: ti: k3-am654: Allow for exclusive and shared device requests Lokesh Vutla
2019-04-10  5:37 ` [PATCH v3 1/5] firmware: ti_sci: Allow for device shared and exclusive requests Lokesh Vutla
2019-04-10  5:37 ` [PATCH v3 2/5] dt-bindings: ti_sci_pm_domains: Add support for exclusive and shared access Lokesh Vutla
2019-04-10  8:04   ` Tero Kristo
2019-04-10 12:37     ` Lokesh Vutla [this message]
2019-04-10 12:49       ` Tero Kristo
2019-04-10 13:15         ` Lokesh Vutla
2019-04-10 15:38           ` Tero Kristo
2019-04-11 14:34             ` Tony Lindgren
2019-05-02  9:24   ` Tero Kristo
2019-06-11 12:34     ` Tero Kristo
2019-06-13 22:22       ` Rob Herring
2019-04-10  5:37 ` [PATCH v3 3/5] soc: ti: " Lokesh Vutla
2019-06-05  5:44   ` Lokesh Vutla
2019-04-10  5:37 ` [PATCH v3 4/5] soc: ti: ti_sci_pm_domains: Switch to SPDX Licensing Lokesh Vutla
2019-04-10  5:37 ` [PATCH v3 5/5] arm64: dts: ti: k3-am654: Update the power domain cells Lokesh Vutla
2019-05-29  8:58 ` [PATCH v3 0/5] soc: ti: k3-am654: Allow for exclusive and shared device requests Lokesh Vutla

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