risc-v/mpfs: introduce CONFIG_MPFS_CLKINIT flag

This CONFIG_MPFS_CLKINIT is set with bootloaders by default. However,
this gives an option to have it unset. In some cases, the clocks
may be already set so it becomes unnecessary to re-initialize them.

Signed-off-by: Eero Nurkkala <eero.nurkkala@offcode.fi>

arch/risc-v/src/mpfs/Kconfig

@@ -46,6 +46,14 @@ config MPFS_BOOTLOADER
 	---help---
 		This NuttX image is used as a bootloader, which will boot only on one hart, putting the others in WFI
 
+config MPFS_CLKINIT
+	bool "Initialize system clocks"
+	depends on MPFS_BOOTLOADER
+	default y
+	---help---
+		This initilizes the system clocks at mpfs_start.c file. The option may be also turned off
+		if some other entity has already set them up.
+
 config MPFS_BOARD_PMP
 	bool "Enable board specific PMP configuration"
 	depends on ARCH_USE_MPU && MPFS_BOOTLOADER

arch/risc-v/src/mpfs/Make.defs

@@ -27,13 +27,17 @@ CMN_ASRCS += mpfs_head.S
 endif
 
 # Specify our C code within this directory to be included
-CHIP_CSRCS  = mpfs_allocateheap.c mpfs_clockconfig.c
+CHIP_CSRCS  = mpfs_allocateheap.c
 CHIP_CSRCS += mpfs_irq.c mpfs_irq_dispatch.c
 CHIP_CSRCS += mpfs_lowputc.c mpfs_serial.c
 CHIP_CSRCS += mpfs_start.c mpfs_timerisr.c
 CHIP_CSRCS += mpfs_gpio.c mpfs_systemreset.c
 CHIP_CSRCS += mpfs_plic.c mpfs_dsn.c
 
+ifeq ($(CONFIG_MPFS_CLKINIT),y)
+CHIP_CSRCS += mpfs_clockconfig.c
+endif
+
 ifeq ($(CONFIG_MPFS_DMA),y)
 CHIP_CSRCS += mpfs_dma.c
 endif

arch/risc-v/src/mpfs/mpfs_start.c

@@ -121,7 +121,7 @@ void __mpfs_start(uint64_t mhartid)
 
   /* Setup PLL if not already provided */
 
-#ifdef CONFIG_MPFS_BOOTLOADER
+#ifdef CONFIG_MPFS_CLKINIT
   mpfs_clockconfig();
 #endif