VLEN describes the length of each vector register and some instructions
need specific minimal VLENs to work correctly.
The vector code already includes a variable riscv_v_vsize that contains
the value of "32 vector registers with vlenb length" that gets filled
during boot. vlenb is the value contained in the CSR_VLENB register and
the value represents "VLEN / 8".
So add riscv_vector_vlen() to return the actual VLEN value for in-kernel
users when they need to check the available VLEN.
Signed-off-by: Heiko Stuebner <heiko.stuebner@vrull.eu>
Reviewed-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: Jerry Shih <jerry.shih@sifive.com>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Link: https://lore.kernel.org/r/20240122002024.27477-2-ebiggers@kernel.org
Signed-off-by: Palmer Dabbelt <palmer@rivosinc.com>
#endif /* CONFIG_RISCV_ISA_V */
+/*
+ * Return the implementation's vlen value.
+ *
+ * riscv_v_vsize contains the value of "32 vector registers with vlenb length"
+ * so rebuild the vlen value in bits from it.
+ */
+static inline int riscv_vector_vlen(void)
+{
+ return riscv_v_vsize / 32 * 8;
+}
+
#endif /* ! __ASM_RISCV_VECTOR_H */