lib: sbi_irqchip: Register devices during cold init

Have the SBI irqchip core keep track of registered irqchip devices. This
is useful for any callbacks the irqchip driver may have, such as for
warm initialization, the external interrupt handler function, and any
future support for handling external interrupts (beyond IPIs) in M-mode.

This improves on the tracking done in fdt_irqchip.c, as it tracks device
instances, not just drivers, so callbacks can target a specific device.

Signed-off-by: Samuel Holland <samuel.holland@sifive.com>
Reviewed-by: Anup Patel <anup@brainfault.org>

include/sbi/sbi_irqchip.h

@@ -10,10 +10,17 @@
 #ifndef __SBI_IRQCHIP_H__
 #define __SBI_IRQCHIP_H__
 
+#include <sbi/sbi_list.h>
 #include <sbi/sbi_types.h>
 
 struct sbi_scratch;
 
+/** irqchip hardware device */
+struct sbi_irqchip_device {
+	/** Node in the list of irqchip devices */
+	struct sbi_dlist node;
+};
+
 /**
  * Set external interrupt handling function
  *
@@ -34,6 +41,9 @@ void sbi_irqchip_set_irqfn(int (*fn)(void));
  */
 int sbi_irqchip_process(void);
 
+/** Register an irqchip device to receive callbacks */
+void sbi_irqchip_add_device(struct sbi_irqchip_device *dev);
+
 /** Initialize interrupt controllers */
 int sbi_irqchip_init(struct sbi_scratch *scratch, bool cold_boot);