Some of the RISC-V drivers (such as RISC-V PMU and ACPI CPPC) need to
access CSR based on CSR number discovered from somewhere. Add common
RISC-V csr_read_num() and csr_write_num() functions under arch/riscv
for such drivers.

These patches can be found in the riscv_csr_read_num_v4 branch at:
https://github.com/avpatel/linux.git

Changes since v3:
 - Rebased on Linux-6.18-rc7
 - Updated commit decription of PATCH1 to reflect the fact that
   we are removing sanity checks on CSR number which are already
   taken care by csr_read_num() and csr_write_num().

Changes since v2:
 - Rebased on Linux-6.18-rc1
 - Added reviewed-by tags

Changes since v1:
 - Make "out_err" mandatory for csr_read_num() and csr_write_num()
   in PATCH2 as suggested by Sunil and Drew. This also helps further
   simplify csr_read_num() and csr_write_num().

Anup Patel (1):
  RISC-V: Add common csr_read_num() and csr_write_num() functions

 arch/riscv/include/asm/csr.h |   3 +
 arch/riscv/kernel/Makefile   |   1 +
 arch/riscv/kernel/csr.c      | 165 +++++++++++++++++++++++++++++++++++
 drivers/acpi/riscv/cppc.c    |  17 ++--
 drivers/perf/riscv_pmu.c     |  54 ++----------
 5 files changed, 184 insertions(+), 56 deletions(-)
 create mode 100644 arch/riscv/kernel/csr.c

-- 
2.43.0