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

[Damien Le Moal]

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