Re: [PATCH v2 1/9] RISC-V: Add AIA related CSR defines

From: Conor Dooley
Date: Wed Jan 04 2023 - 18:07:34 EST


Hey Anup!

On Tue, Jan 03, 2023 at 07:44:01PM +0530, Anup Patel wrote:
> The RISC-V AIA specification improves handling per-HART local interrupts
> in a backward compatible manner. This patch adds defines for new RISC-V
> AIA CSRs.
>
> Signed-off-by: Anup Patel <apatel@xxxxxxxxxxxxxxxx>
> ---
> arch/riscv/include/asm/csr.h | 92 ++++++++++++++++++++++++++++++++++++
> 1 file changed, 92 insertions(+)
>
> diff --git a/arch/riscv/include/asm/csr.h b/arch/riscv/include/asm/csr.h
> index 0e571f6483d9..4e1356bad7b2 100644
> --- a/arch/riscv/include/asm/csr.h
> +++ b/arch/riscv/include/asm/csr.h
> @@ -73,7 +73,10 @@
> #define IRQ_S_EXT 9
> #define IRQ_VS_EXT 10
> #define IRQ_M_EXT 11
> +#define IRQ_S_GEXT 12
> #define IRQ_PMU_OVF 13
> +#define IRQ_LOCAL_MAX (IRQ_PMU_OVF + 1)
> +#define IRQ_LOCAL_MASK ((_AC(1, UL) << IRQ_LOCAL_MAX) - 1)
>
> /* Exception causes */
> #define EXC_INST_MISALIGNED 0
> @@ -156,6 +159,26 @@
> (_AC(1, UL) << IRQ_S_TIMER) | \
> (_AC(1, UL) << IRQ_S_EXT))
>
> +/* AIA CSR bits */
> +#define TOPI_IID_SHIFT 16
> +#define TOPI_IID_MASK 0xfff
> +#define TOPI_IPRIO_MASK 0xff
> +#define TOPI_IPRIO_BITS 8
> +
> +#define TOPEI_ID_SHIFT 16
> +#define TOPEI_ID_MASK 0x7ff
> +#define TOPEI_PRIO_MASK 0x7ff
> +
> +#define ISELECT_IPRIO0 0x30
> +#define ISELECT_IPRIO15 0x3f
> +#define ISELECT_MASK 0x1ff
> +
> +#define HVICTL_VTI 0x40000000
> +#define HVICTL_IID 0x0fff0000
> +#define HVICTL_IID_SHIFT 16
> +#define HVICTL_IPRIOM 0x00000100
> +#define HVICTL_IPRIO 0x000000ff

Why not name these as masks, like you did for the other masks?
Also, the mask/shift defines appear inconsistent. TOPI_IID_MASK is
intended to be used post-shift AFAICT, but HVICTL_IID_SHIFT is intended
to be used *pre*-shift.
Some consistency in naming and function would be great.


> +/* Machine-Level High-Half CSRs (AIA) */
> +#define CSR_MIDELEGH 0x313

I feel like I could find Midelegh in an Irish dictionary lol
Anyways, I went through the CSRs and they do all seem correct.

Thanks,
Conor.


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