[PATCH 05/18] dbtr: Do not support chain bit

[Himanshu Chauhan]

On Fri, Mar 13, 2026 at 03:19:34PM +1000, Nicholas Piggin wrote:
> There is no chain bit validation in in SBI, so do not support it.
> 
> Signed-off-by: Nicholas Piggin <npiggin at gmail.com>
> ---
>  lib/sbi/sbi_dbtr.c | 14 ++++++++++++--
>  1 file changed, 12 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/sbi/sbi_dbtr.c b/lib/sbi/sbi_dbtr.c
> index 65c3b2df..224f2350 100644
> --- a/lib/sbi/sbi_dbtr.c
> +++ b/lib/sbi/sbi_dbtr.c
> @@ -466,11 +466,21 @@ static void dbtr_trigger_clear(struct sbi_dbtr_trigger *trig)
>  	csr_write(CSR_TDATA2, 0x0);
>  }
>  
> -static int dbtr_trigger_supported(unsigned long type)
> +static int dbtr_trigger_supported(unsigned long type, unsigned long tdata)
>  {
>  	switch (type) {
>  	case RISCV_DBTR_TRIG_MCONTROL:
> +		/*
> +		 * SBI currently does not validate chain bit in install/update
> +		 * so we do not support it.
> +		 */
> +		if (tdata & RV_DBTR_BIT_MASK(MC, CHAIN))

Just a minor suggestion. Since it may be supported in future, I would suggest that
we print a warning message that a trigger with chain support was asked for.

> +			return 0;
> +		return 1;
>  	case RISCV_DBTR_TRIG_MCONTROL6:
> +		if (tdata & RV_DBTR_BIT_MASK(MC6, CHAIN))
ditto

Otherwise looks good.

Reviewed-by: Himanshu Chauhan <himanshu.chauhan at oss.qualcomm.com>

Thanks
Regards
Himanshu

> +			return 0;
> +		return 1;
>  	case RISCV_DBTR_TRIG_ICOUNT:
>  		return 1;
>  	default:
> @@ -613,7 +623,7 @@ int sbi_dbtr_install_trig(unsigned long smode,
>  		recv = (struct sbi_dbtr_data_msg *)(&entry->data);
>  		tdata1 = lle_to_cpu(recv->tdata1);
>  
> -		if (!dbtr_trigger_supported(TDATA1_GET_TYPE(tdata1))) {
> +		if (!dbtr_trigger_supported(TDATA1_GET_TYPE(tdata1), tdata1)) {
>  			*out = _idx;
>  			sbi_hart_protection_unmap_range((unsigned long)shmem_base,
>  							trig_count * sizeof(*entry));
> -- 
> 2.51.0
> 
> 
> -- 
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