[PATCH 11/11] riscv: Add option to disable writes to mcounteren

[Sean Anderson]

On the kendryte k210, writes to mcounteren result in an illegal instruction
exception.

Signed-off-by: Sean Anderson <seanga2 at gmail.com>
---
 arch/riscv/cpu/cpu.c            | 2 ++
 board/sipeed/maix/Kconfig       | 1 +
 configs/sipeed_maix_bitm_config | 1 +
 3 files changed, 4 insertions(+)

diff --git a/arch/riscv/cpu/cpu.c b/arch/riscv/cpu/cpu.c
index e457f6acbf..df9eae663c 100644
--- a/arch/riscv/cpu/cpu.c
+++ b/arch/riscv/cpu/cpu.c
@@ -89,7 +89,9 @@ int arch_cpu_init_dm(void)
 		 * Enable perf counters for cycle, time,
 		 * and instret counters only
 		 */
+#ifndef CONFIG_SYS_RISCV_NOCOUNTER
 		csr_write(CSR_MCOUNTEREN, GENMASK(2, 0));
+#endif

 		/* Disable paging */
 		if (supports_extension('s'))
diff --git a/board/sipeed/maix/Kconfig b/board/sipeed/maix/Kconfig
index 6a25086ef4..c456c47fb2 100644
--- a/board/sipeed/maix/Kconfig
+++ b/board/sipeed/maix/Kconfig
@@ -37,6 +37,7 @@ config BOARD_SPECIFIC_OPTIONS
 	select SIFIVE_SERIAL
 	select ARCH_DEFAULT_RV64I
 	select ENV_IS_NOWHERE
+	select SYS_RISCV_NOCOUNTER
 	imply SIFIVE_CLINT
 	imply K210_SYSCTL
 	imply CLK_K210
diff --git a/configs/sipeed_maix_bitm_config b/configs/sipeed_maix_bitm_config
index 0088748ae0..73075e3016 100644
--- a/configs/sipeed_maix_bitm_config
+++ b/configs/sipeed_maix_bitm_config
@@ -30,6 +30,7 @@ CONFIG_RISCV_ISA_A=y
 CONFIG_SIFIVE_CLINT=y
 CONFIG_K210_SYSCTL=y
 CONFIG_SHOW_REGS=y
+CONFIG_SYS_RISCV_NOCOUNTER=y
 CONFIG_STACK_SIZE_SHIFT=14
 CONFIG_LOCALVERSION=""
 CONFIG_CC_OPTIMIZE_FOR_SIZE=y
-- 
2.24.1