drivers : interrupt: alignment of cascaded IRQs

The base irq of the first created cascaded struct is currently equal to
PLATFORM_IRQ_HW_NUM, which is 32 on HIFI4.

On IMX platform the number of children per such a struct is equal to 64
(as per IMX steer IRQ mapping).

Since steer irq in range [0-63] are not routed to the DSP on IMX8 it is
possible to create the cascaded structs only from 64.

Starting them from 32 creates a bias in the management of interrupts,
making the storing of the irq-handlers un-natural and complicated.

This commit wants to replace the initialization of cascade_root.last_irq
by a new constant PLATFORM_IRQ_FIRST_CHILD which would be defined at
platform level.

In the case of IMX it takes value 0, while in all other platform it takes
the value PLATFORM_IRQ_HW_NUM in order to keep things as they are.

Signed-off-by: Jerome Laclavere <jerome.laclavere@nxp.com>

src/drivers/interrupt.c

@@ -142,7 +142,7 @@ struct irq_cascade_desc *interrupt_get_parent(uint32_t irq)
 
 void interrupt_init(void)
 {
-	cascade_root.last_irq = PLATFORM_IRQ_HW_NUM - 1;
+	cascade_root.last_irq = PLATFORM_IRQ_FIRST_CHILD - 1;
 	dcache_writeback_region(&cascade_root, sizeof(cascade_root));
 	spinlock_init(&cascade_lock);
 }

src/platform/apollolake/include/platform/drivers/interrupt.h

@@ -15,6 +15,7 @@
 #include <config.h>
 
 #define PLATFORM_IRQ_HW_NUM	XCHAL_NUM_INTERRUPTS
+#define PLATFORM_IRQ_FIRST_CHILD  PLATFORM_IRQ_HW_NUM
 #define PLATFORM_IRQ_CHILDREN	32
 
 /* IRQ numbers - wrt Tensilica DSP */

src/platform/baytrail/include/platform/drivers/interrupt.h

@@ -96,6 +96,7 @@
 
 /* no nested interrupts */
 #define PLATFORM_IRQ_HW_NUM	XCHAL_NUM_INTERRUPTS
+#define PLATFORM_IRQ_FIRST_CHILD  PLATFORM_IRQ_HW_NUM
 #define PLATFORM_IRQ_CHILDREN	0
 
 #endif /* __PLATFORM_DRIVERS_INTERRUPT_H__ */

src/platform/cannonlake/include/platform/drivers/interrupt.h

@@ -16,6 +16,7 @@
 #include <config.h>
 
 #define PLATFORM_IRQ_HW_NUM	XCHAL_NUM_INTERRUPTS
+#define PLATFORM_IRQ_FIRST_CHILD  PLATFORM_IRQ_HW_NUM
 #define PLATFORM_IRQ_CHILDREN	32
 
 /* IRQ numbers - wrt Tensilica DSP */

src/platform/haswell/include/platform/drivers/interrupt.h

@@ -14,6 +14,7 @@
 #include <config.h>
 
 #define PLATFORM_IRQ_HW_NUM	XCHAL_NUM_INTERRUPTS
+#define PLATFORM_IRQ_FIRST_CHILD  PLATFORM_IRQ_HW_NUM
 #define PLATFORM_IRQ_CHILDREN	0
 
 /* IRQ numbers */

src/platform/icelake/include/platform/drivers/interrupt.h

@@ -16,6 +16,7 @@
 #include <config.h>
 
 #define PLATFORM_IRQ_HW_NUM	XCHAL_NUM_INTERRUPTS
+#define PLATFORM_IRQ_FIRST_CHILD  PLATFORM_IRQ_HW_NUM
 #define PLATFORM_IRQ_CHILDREN	32
 
 /* IRQ numbers - wrt Tensilica DSP */

src/platform/imx8/include/platform/drivers/interrupt.h

@@ -60,7 +60,9 @@
 
 /* 32 HW interrupts + 8 IRQ_STEER lines each with 64 interrupts */
 #define PLATFORM_IRQ_HW_NUM	XCHAL_NUM_INTERRUPTS
-#define PLATFORM_IRQ_CHILDREN	64
+#define PLATFORM_IRQ_CHILDREN	64 /* Each cascaded struct covers 64 IRQs */
+/* IMX: Covered steer IRQs are modulo-64 aligned. */
+#define PLATFORM_IRQ_FIRST_CHILD  0
 
 /* irqstr_get_sof_int() - Convert IRQ_STEER interrupt to SOF logical
  * interrupt

src/platform/suecreek/include/platform/drivers/interrupt.h

@@ -17,6 +17,7 @@
 #include <config.h>
 
 #define PLATFORM_IRQ_HW_NUM	XCHAL_NUM_INTERRUPTS
+#define PLATFORM_IRQ_FIRST_CHILD  PLATFORM_IRQ_HW_NUM
 #define PLATFORM_IRQ_CHILDREN	32
 
 /* IRQ numbers - wrt Tensilica DSP */

src/platform/tigerlake/include/platform/drivers/interrupt.h

@@ -16,6 +16,7 @@
 #include <config.h>
 
 #define PLATFORM_IRQ_HW_NUM	XCHAL_NUM_INTERRUPTS
+#define PLATFORM_IRQ_FIRST_CHILD  PLATFORM_IRQ_HW_NUM
 #define PLATFORM_IRQ_CHILDREN	32
 
 /* IRQ numbers - wrt Tensilica DSP */