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Subject: Re: [PATCH 5/7] ARM: dts: rtd1195: Introduce r-bus
To:     James Tai <james.tai@realtek.com>
Cc:     "linux-realtek-soc@lists.infradead.org" 
        <linux-realtek-soc@lists.infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        "devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
        <linux-arm-kernel@lists.infradead.org>
References: <20191111030434.29977-1-afaerber@suse.de>
 <20191111030434.29977-6-afaerber@suse.de>
 <a43d184d74c34e269714858b2635c35e@realtek.com>
From:   =?UTF-8?Q?Andreas_F=c3=a4rber?= <afaerber@suse.de>
Organization: SUSE Software Solutions Germany GmbH
Message-ID: <960a80b9-b1bf-3709-bbb7-fc2a3c3ae1da@suse.de>
Date:   Fri, 15 Nov 2019 01:16:48 +0100
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Hi James,

Am 13.11.19 um 03:53 schrieb James Tai:
>> +		rbus: r-bus@18000000 {
>> +			compatible = "simple-bus";
>> +			reg = <0x18000000 0x100000>;
>> +			#address-cells = <1>;
>> +			#size-cells = <1>;
>> +			ranges = <0x0 0x18000000 0x100000>;
>> +
> 
> The r-bus size of RTD1195 is 0x70000‬.

Fixed, also further above for the soc node. This now leaves a gap until
0x18100000 - is that gap RAM or non-r-bus registers then?

		ranges = <0x18000000 0x18000000 0x00070000>,
		         <0x18100000 0x18100000 0x01000000>,
		         <0x40000000 0x40000000 0xc0000000>;

Did you also review the other two ranges? The middle one was labeled NOR
flash somewhere - are start and size correct? The final one depends on
the maximum RAM size - does RTD1195 allow more than 1 GiB RAM? All
non-RAM regions should be covered here.

So another question, applicable to all SoCs: This reserved Boot ROM area
at the start of the address space, here of size 0xa800, is that copied
into RAM, or is that the actual ROM overlapping RAM? If the latter, we
should exclude it from /memory@0's reg (making it /memory@a800), and add
it to soc's ranges here for correctness.

With the follow-up question: Is it correct that, given the size 0xa800,
I have a gap between /memreserve/s from 0xa800 to 0xc000, or should we
reserve that gap by extending the next /memreserve/ or inserting one?

Thanks,
Andreas

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