Re: [PATCH v3 0/3] Add RISC-V 32 NOMMU support

From: Damien Le Moal <damien.lemoal@opensource.wdc.com>
To: Randy Dunlap <rdunlap@infradead.org>,
	Jesse Taube <mr.bossman075@gmail.com>,
	linux-riscv@lists.infradead.org
Cc: linux-clk@vger.kernel.org, linux-kernel@vger.kernel.org,
	Yimin Gu <ustcymgu@gmail.com>,
	Damien Le Moal <damien.lemoal@wdc.com>,
	Stephen Boyd <sboyd@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Waldemar Brodkorb <wbx@openadk.org>,
	Albert Ou <aou@eecs.berkeley.edu>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Paul Walmsley <paul.walmsley@sifive.com>
Subject: Re: [PATCH v3 0/3] Add RISC-V 32 NOMMU support
Date: Wed, 1 Mar 2023 13:42:42 +0900	[thread overview]
Message-ID: <556ce787-80eb-dc48-f8d6-83e415538e36@opensource.wdc.com> (raw)
In-Reply-To: <42446784-a88b-df09-41e9-5f685b4df6ee@infradead.org>

On 3/1/23 13:07, Randy Dunlap wrote:
> Hi--
> 
> On 2/28/23 16:26, Jesse Taube wrote:
>> This patch-set aims to add NOMMU support to RV32.
>> Many people want to build simple emulators or HDL
>> models of RISC-V this patch makes it possible to
>> run linux on them.
>>
>> Yimin Gu is the original author of this set.
>> Submitted here:
>> https://lists.buildroot.org/pipermail/buildroot/2022-November/656134.html
>>
>> Though Jesse T rewrote the Dconf.
> 
> Dconf?
> 
>>
>> The new set:
>> https://lists.buildroot.org/pipermail/buildroot/2022-December/658258.html
>> ---
>> V1->V2:
>>  - Add Conor's clock patch for implicit div64
>>  - Fix typo in commit title 3/3
>>  - Fix typo in commit description 2/3
>> V2->V3
>>  - Change from defconfig file to a PHONY config
>> ---
> 
> Is this 'rv32_nommu_virt_defconfig' target the only build target
> that is supported?
> 
> I ask because I applied the 3 patches and did 25 randconfig builds.
> 5 of them failed the same way:
> 
> riscv32-linux-ld: drivers/soc/canaan/k210-sysctl.o: in function `k210_soc_early_init':
> k210-sysctl.c:(.init.text+0x78): undefined reference to `k210_clk_early_init'

Arg. Forgot about that. k210 is rv64 only and while the clk driver could still
compile test with rv32 (or any arch), that driver provides the
k210_clk_early_init() function which is called very early in the boot process
from k210_soc_early_init(), which is an SOC_EARLY_INIT_DECLARE() call. The
problem may be there. Probably should be disabled for rv32 if no SoC need that
sort of early init call.

> 
> because
> # CONFIG_COMMON_CLK_K210 is not set
> 
> 
> Maybe SOC_CANAAN needs some more selects for required code?
> 
>> Conor Dooley (1):
>>   clk: k210: remove an implicit 64-bit division
>>
>> Jesse Taube (1):
>>   riscv: configs: Add nommu PHONY defconfig for RV32
>>
>> Yimin Gu (1):
>>   riscv: Kconfig: Allow RV32 to build with no MMU
>>
>>  arch/riscv/Kconfig     | 5 ++---
>>  arch/riscv/Makefile    | 4 ++++
>>  drivers/clk/clk-k210.c | 2 +-
>>  3 files changed, 7 insertions(+), 4 deletions(-)
>>
> 

-- 
Damien Le Moal
Western Digital Research