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From: Dmitry Osipenko <digetx@gmail.com>
To: Joseph Lo <josephl@nvidia.com>,
	Thierry Reding <thierry.reding@gmail.com>,
	Peter De Schrijver <pdeschrijver@nvidia.com>,
	Jonathan Hunter <jonathanh@nvidia.com>,
	Rob Herring <robh+dt@kernel.org>, Stephen Boyd <sboyd@kernel.org>
Cc: linux-tegra@vger.kernel.org, devicetree@vger.kernel.org,
	linux-clk@vger.kernel.org, linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH V3 1/8] dt-bindings: memory: tegra: Add external memory controller binding for Tegra210
Date: Thu, 16 May 2019 17:39:05 +0300
Message-ID: <1a5b539a-03bb-c326-8ba2-56ea8de97237@gmail.com> (raw)
In-Reply-To: <f1e4ab1e-11b9-ba65-20b8-35c6459d2410@nvidia.com>

16.05.2019 12:01, Joseph Lo пишет:
> On 5/15/19 9:50 PM, Dmitry Osipenko wrote:
>> 15.05.2019 10:17, Joseph Lo пишет:
>>> On 5/15/19 12:28 AM, Dmitry Osipenko wrote:
>>>> 10.05.2019 11:47, Joseph Lo пишет:
>>>>> Add the binding document for the external memory controller (EMC)
>>>>> which
>>>>> communicates with external LPDDR4 devices. It includes the bindings of
>>>>> the EMC node and a sub-node of EMC table which under the reserved
>>>>> memory
>>>>> node. The EMC table contains the data of the rates that EMC supported.
>>>>>
>>>>> Signed-off-by: Joseph Lo <josephl@nvidia.com>
>>>>> ---
>>>>> v3:
>>>>> - drop the bindings of EMC table
>>>>> - add memory-region and reserved-memory node for EMC table
>>>>> ---
>>>>>    .../nvidia,tegra210-emc.txt                   | 55
>>>>> +++++++++++++++++++
>>>>>    1 file changed, 55 insertions(+)
>>>>>    create mode 100644
>>>>> Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.txt
>>>>>
>>>>>
>>>>>
>>>>> diff --git
>>>>> a/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.txt
>>>>>
>>>>> b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.txt
>>>>>
>>>>>
>>>>> new file mode 100644
>>>>> index 000000000000..d65aeef2329c
>>>>> --- /dev/null
>>>>> +++
>>>>> b/Documentation/devicetree/bindings/memory-controllers/nvidia,tegra210-emc.txt
>>>>>
>>>>>
>>>>> @@ -0,0 +1,55 @@
>>>>> +NVIDIA Tegra210 SoC EMC (external memory controller)
>>>>> +====================================================
>>>>> +
>>>>> +Device node
>>>>> +===========
>>>>> +Required properties :
>>>>> +- compatible : should be "nvidia,tegra210-emc".
>>>>> +- reg : physical base address and length of the controller's
>>>>> registers.
>>>>> +- clocks : phandles of the possible source clocks.
>>>>> +- clock-names : names of the possible source clocks.
>>>>> +- interrupts : Should contain the EMC general interrupt.
>>>>> +- memory-region : phandle to the reserved memory (see
>>>>> +
>>>>> Documentation/devicetree/bindings/reserved-memory/reserved-memory.txt)
>>>>> which
>>>>>
>>>>> +  contains a sub-node of EMC table.
>>>>> +- nvidia,memory-controller : phandle of the memory controller.
>>>>> +
>>>>> +Reserved memory node
>>>>> +====================
>>>>> +Should contain a sub-node of EMC table with required properties:
>>>>> +- compatible : should be "nvidia,tegra210-emc-table".
>>>>> +- reg : physical address and length of the location of EMC table.
>>>>> +
>>>>> +Example:
>>>>> +    reserved-memory {
>>>>> +        #address-cells = <2>;
>>>>> +        #size-cells = <2>;
>>>>> +        ranges;
>>>>> +
>>>>> +        emc_table: emc-table@8be00000 {
>>>>> +            compatible = "nvidia,tegra210-emc-table";
>>>>> +            reg = <0x0 0x8be00000 0x0 0x10000>;
>>>>> +            status = "okay";
>>>>> +        };
>>>>
>>>> You essentially moved the v1 binding into obscure and undocumented
>>>> blob,
>>>> ignoring previous review comments. This is a very odd move... please
>>>> explain what is going on.
>>>>
>>>
>>> Discussed with Thierry offline which way we prefer to pass the EMC table
>>> to the kernel. Some reasons below we decide to chose this one (via
>>> binary blob).
>>>
>>> - The EMC table is much bigger than the previous Tegra generations
>>> (LPDDR4 v.s. LPDDR2/3). It's harder to settle in the review process. And
>>> if there is a new fix of the table in the future, we'll need to go
>>> through that again.
>>
>> I don't think that this a very good excuse for not documenting the
>> blob's structure.
> 
> The blob's structure is in patch 4 now that we originally wanted to
> describe below. Basically, the content is the same.
> http://patchwork.ozlabs.org/patch/1084467/
> http://patchwork.ozlabs.org/patch/1063879/

I'm not asking about what exactly it is, but saying that every supported
blob structure version should be documented in my opinion, otherwise the
documentation is not really useful.

  reply index

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-10  8:47 [PATCH V3 0/8] Add EMC scaling support " Joseph Lo
2019-05-10  8:47 ` [PATCH V3 1/8] dt-bindings: memory: tegra: Add external memory controller binding " Joseph Lo
2019-05-14 16:28   ` Dmitry Osipenko
2019-05-15  7:17     ` Joseph Lo
2019-05-15 13:50       ` Dmitry Osipenko
2019-05-16  9:01         ` Joseph Lo
2019-05-16 14:39           ` Dmitry Osipenko [this message]
2019-05-10  8:47 ` [PATCH V3 2/8] clk: tegra: Add PLLP_UD and PLLMB_UD " Joseph Lo
2019-05-10  8:47 ` [PATCH V3 3/8] clk: tegra: Export functions for EMC clock scaling Joseph Lo
2019-05-14 16:29   ` Dmitry Osipenko
2019-05-15  7:25     ` Joseph Lo
2019-05-10  8:47 ` [PATCH V3 4/8] memory: tegra: Add Tegra210 EMC clock driver Joseph Lo
2019-05-13 16:54   ` Dmitry Osipenko
2019-05-14  9:22     ` Joseph Lo
2019-05-14 17:04   ` Dmitry Osipenko
2019-05-15  8:42     ` Joseph Lo
2019-05-15 15:25       ` Dmitry Osipenko
2019-05-16  7:52         ` Joseph Lo
2019-05-16 14:29           ` Dmitry Osipenko
2019-05-10  8:47 ` [PATCH V3 5/8] memory: tegra: Add EMC scaling support code for Tegra210 Joseph Lo
2019-05-13 17:02   ` Dmitry Osipenko
2019-05-14  8:47     ` Joseph Lo
2019-05-14 16:30   ` Dmitry Osipenko
2019-05-15 14:09   ` Dmitry Osipenko
2019-05-15 15:26   ` Dmitry Osipenko
2019-05-10  8:47 ` [PATCH V3 6/8] memory: tegra: Add EMC scaling sequence " Joseph Lo
2019-05-10  8:47 ` [PATCH V3 7/8] clk: tegra: Remove the old emc_mux clock " Joseph Lo
2019-05-10  8:47 ` [PATCH V3 8/8] arm64: tegra: Add external memory controller node " Joseph Lo

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