drivers: intc: plic: implement irq affinity configuration

- Implement irq-set-affinity in RISCV PLIC.
- Added new affinity shell command to get/set the irq(s)
  affinity in runtime, when `0` is sent as the `local_irq`, it
  means set/get all IRQs affinity.
- Some minor optimizations

Updated the build_all test to build this new configuration.

Signed-off-by: Yong Cong Sin <ycsin@meta.com>
Signed-off-by: Yong Cong Sin <yongcong.sin@gmail.com>

Author: ycsin

arch/riscv/core/smp.c

@@ -74,7 +74,11 @@ void arch_secondary_cpu_init(int hartid)
 #endif
 #ifdef CONFIG_SMP
 	irq_enable(RISCV_IRQ_MSOFT);
-#endif
+#ifdef CONFIG_PLIC_IRQ_AFFINITY
+	/* Enable on secondary cores so that they can respond to PLIC */
+	irq_enable(RISCV_IRQ_MEXT);
+#endif /* CONFIG_PLIC_IRQ_AFFINITY */
+#endif /* CONFIG_SMP */
 	riscv_cpu_init[cpu_num].fn(riscv_cpu_init[cpu_num].arg);
 }
 

drivers/interrupt_controller/Kconfig.plic

@@ -13,11 +13,43 @@ config PLIC
 
 if PLIC
 
+config PLIC_IRQ_AFFINITY
+	bool "Configure IRQ affinity"
+	depends on SMP
+	depends on MP_MAX_NUM_CPUS > 1
+	help
+	  Enable configuration of IRQ affinity.
+
+config PLIC_IRQ_AFFINITY_MASK
+	hex "Default IRQ affinity mask"
+	depends on PLIC_IRQ_AFFINITY
+	default 0x1
+	help
+	  Default mask for the driver when IRQ affinity is enabled.
+
 config PLIC_SHELL
 	bool "PLIC shell commands"
 	depends on SHELL
 	help
 	  Enable additional shell commands useful for debugging.
 	  Caution: This can use quite a bit of RAM (PLICs * IRQs * sizeof(uint16_t)).
 
+if PLIC_SHELL
+
+config PLIC_SHELL_IRQ_COUNT
+	bool "IRQ count shell commands"
+	default y
+	help
+	  Records the number of hits per interrupt line and provide shell commands to access them.
+	  Caution: This can use quite a bit of RAM (PLICs * IRQs * sizeof(PLIC_IRQ_COUNT_TYPE)).
+
+config PLIC_SHELL_IRQ_AFFINITY
+	bool "Shell commands to configure IRQ affinity"
+	default y
+	depends on PLIC_IRQ_AFFINITY
+	help
+	  Provide shell commands to configure IRQ affinity in runtime.
+
+endif # PLIC_SHELL
+
 endif # PLIC