On Sat, Oct 21, 2023 at 10:05 PM Greg Kroah-Hartman
[off-list ref] wrote:

On Fri, Oct 20, 2023 at 12:51:37PM +0530, Anup Patel wrote:

quoted

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 <redacted>
Reviewed-by: Andrew Jones <redacted>
---
 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 12dfda6bb924..cbcefa344417 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 -1; }

Why not return a real error, "-1" isn't that :)

As-per SBI spec, the legacy sbi_console_getchar() returns
-1 upon failure hence the code.

Refer, section 5.3 of the latest SBI spec
https://github.com/riscv-non-isa/riscv-sbi-doc/releases/download/commit-fe4562532a9cc57e5743b6466946c5e5c98c73ca/riscv-sbi.pdf

Although, the users of this function only expect a negative
value upon failure so better to return proper error code here.

I will update.

thanks,

greg k-h

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Regards,
Anup