Re: [PATCH v4 1/5] RISC-V: Add stubs for sbi_console_putchar/getchar()

Samuel Holland
2023-11-23T14:45:33Z

Hi Anup,

On 2023-11-23 4:38 AM, Anup Patel wrote:
> On Wed, Nov 22, 2023 at 4:06 AM Samuel Holland
> <samuel.holland@sifive.com> wrote:
>> On 2023-11-17 9:38 PM, Anup Patel wrote:
>>> The functions sbi_console_putchar() and sbi_console_getchar() are
>>> not defined when CONFIG_RISCV_SBI_V01 is disabled so let us add
>>> stub of these functions to avoid "#ifdef" on user side.
>>>
>>> Signed-off-by: Anup Patel <apatel@ventanamicro.com>
>>> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>
>>> ---
>>> arch/riscv/include/asm/sbi.h | 5 +++++
>>> 1 file changed, 5 insertions(+)
>>>
>>> diff --git a/arch/riscv/include/asm/sbi.h b/arch/riscv/include/asm/sbi.h
>>> index 0892f4421bc4..66f3933c14f6 100644
>>> --- a/arch/riscv/include/asm/sbi.h
>>> +++ b/arch/riscv/include/asm/sbi.h
>>> @@ -271,8 +271,13 @@ struct sbiret sbi_ecall(int ext, int fid, unsigned long arg0,
>>> unsigned long arg3, unsigned long arg4,
>>> unsigned long arg5);
>>>
>>> +#ifdef CONFIG_RISCV_SBI_V01
>>> void sbi_console_putchar(int ch);
>>> int sbi_console_getchar(void);
>>> +#else
>>> +static inline void sbi_console_putchar(int ch) { }
>>> +static inline int sbi_console_getchar(void) { return -ENOENT; }
>>
>> "The SBI call returns the byte on success, or -1 for failure."
>>
>> So -ENOENT is not really an appropriate value to return here.
>
> Actually, I had -1 over here previously but based on GregKH's
> suggestion, we are now returning proper Linux error code here.
>
> Also, all users of sbi_console_getchar() onlyl expect a negative
> value upon error so better to return proper Linux error code.

Alright, makes sense to me.

Regards,
Samuel