[PATCH v6 04/21] RISC-V: Define indirect CSR access helpers

[Atish Patra]

On 6/21/26 11:42 PM, Charlie Jenkins wrote:
> On Mon, Jun 08, 2026 at 11:01:18PM -0700, Atish Patra wrote:
>> From: Atish Patra <atishp at rivosinc.com>
>>
>> The indriect CSR requires multiple instructions to read/write CSR.
> indirect
>
>> Add a few helper functions for ease of usage.
>>
>> Signed-off-by: Atish Patra <atishp at rivosinc.com>
>> ---
>>   arch/riscv/include/asm/csr_ind.h | 44 ++++++++++++++++++++++++++++++++++++++++
>>   1 file changed, 44 insertions(+)
>>
>> diff --git a/arch/riscv/include/asm/csr_ind.h b/arch/riscv/include/asm/csr_ind.h
>> new file mode 100644
>> index 000000000000..6fd7d44dc640
>> --- /dev/null
>> +++ b/arch/riscv/include/asm/csr_ind.h
>> @@ -0,0 +1,44 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * Copyright (C) 2024 Rivos Inc.
> I don't think it makes sense to introduce this copyright in new commits.
Yeah. I will update these.
> - Charlie
>
>> + */
>> +
>> +#ifndef _ASM_RISCV_CSR_IND_H
>> +#define _ASM_RISCV_CSR_IND_H
>> +
>> +#include <linux/irqflags.h>
>> +
>> +#include <asm/csr.h>
>> +
>> +#define csr_ind_read(iregcsr, iselbase, iseloff) ({		\
>> +	unsigned long __value = 0;				\
>> +	unsigned long __flags;					\
>> +	local_irq_save(__flags);				\
>> +	csr_write(CSR_ISELECT, (iselbase) + (iseloff));		\
>> +	__value = csr_read(iregcsr);				\
>> +	local_irq_restore(__flags);				\
>> +	__value;						\
>> +})
>> +
>> +#define csr_ind_write(iregcsr, iselbase, iseloff, value) ({	\
>> +	unsigned long __flags;					\
>> +	local_irq_save(__flags);				\
>> +	csr_write(CSR_ISELECT, (iselbase) + (iseloff));		\
>> +	csr_write(iregcsr, (value));				\
>> +	local_irq_restore(__flags);				\
>> +})
>> +
>> +#define csr_ind_warl(iregcsr, iselbase, iseloff, warl_val) ({	\
>> +	unsigned long __old_val = 0, __value = 0;		\
>> +	unsigned long __flags;					\
>> +	local_irq_save(__flags);				\
>> +	csr_write(CSR_ISELECT, (iselbase) + (iseloff));		\
>> +	__old_val = csr_read(iregcsr);				\
>> +	csr_write(iregcsr, (warl_val));				\
>> +	__value = csr_read(iregcsr);				\
>> +	csr_write(iregcsr, __old_val);				\
>> +	local_irq_restore(__flags);				\
>> +	__value;						\
>> +})
>> +
>> +#endif
>>
>> -- 
>> 2.53.0-Meta
>>
>>
>> _______________________________________________
>> linux-riscv mailing list
>> linux-riscv at lists.infradead.org
>> http://lists.infradead.org/mailman/listinfo/linux-riscv
>>