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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" 
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        Mark Rutland <mark.rutland@arm.com>,
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From:   =?UTF-8?Q?Andreas_F=c3=a4rber?= <afaerber@suse.de>
Organization: SUSE Software Solutions Germany GmbH
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Date:   Tue, 19 Nov 2019 12:15:28 +0100
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Hi James,

Am 18.11.19 um 07:53 schrieb James Tai:
>> 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.
>>
> Yes, we should exclude it from /memory@0's reg.

OK, will look into it.

> 
>> 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?
> 
> We should reserve memory address from 0x0000 to 0xa800 for the internal ROM.

Please see [1] - I had already updated the second reservation to start
at 0xa800 and extended it to 0x100000 before your response here.

The previous "bootcode" size of 0xc000 can be found here:
https://github.com/BPI-SINOVOIP/BPI-M4-bsp/blob/master/linux-rtk/arch/arm/mach-rtd119x/include/mach/memory.h
https://github.com/BPI-SINOVOIP/BPI-M4-bsp/blob/master/linux-rtk/arch/arm/boot/dts/realtek/rtd119x/rtd-119x-horseradish.dts

As you can see the 0xc000 and 0xf4000 were hardcoded and did not depend
on SYS_BOOTCODE_MEMSIZE...
For later SoCs I saw some FIXME(?) comment that area up to 0x100000 was
reserved due to some Jira ticket and should get fixed? Any insights on
what is in that memory range causing problems?

Regards,
Andreas

[1] https://patchwork.kernel.org/patch/11248033/

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