ARC: forbid FIRQ or multiple register banks w/ 1 IRQ priority level
Don't allow to enable multiple register banks / fast
interrupts if we have only one interrupt priority level.
NOTE: we duplicate some checks by adding dependencies to ARC
Kconfig and adding build-time checks in C code. We do it
intentionally as for some reason we can violate dependencies
in architecture-level Kconfig by adding incorrect default in
SoC-level Kconfig. Such violation happens without any
warnings / errors from the Kconfig.
Signed-off-by: Eugeniy Paltsev <Eugeniy.Paltsev@synopsys.com>
Signed-off-by: Evgeniy Paltsev <PaltsevEvgeniy@gmail.com>
diff --git a/arch/arc/Kconfig b/arch/arc/Kconfig
index 5b0dff0..5fd90cb 100644
--- a/arch/arc/Kconfig
+++ b/arch/arc/Kconfig
@@ -136,6 +136,7 @@
config RGF_NUM_BANKS
int "Number of General Purpose Register Banks"
depends on ARC_FIRQ
+ depends on NUM_IRQ_PRIO_LEVELS > 1
range 1 2
default 2
help
@@ -145,10 +146,15 @@
If fast interrupts are supported but there is only 1
register bank, the fast interrupt handler must save
and restore general purpose registers.
+ NOTE: it's required to have more than one interrupt priority level
+ to use second register bank - otherwise all interrupts will use
+ same register bank. Such configuration isn't supported in software
+ and it is not beneficial from the performance point of view.
config ARC_FIRQ
bool "FIRQ enable"
depends on ISA_ARCV2
+ depends on NUM_IRQ_PRIO_LEVELS > 1
default y
help
Fast interrupts are supported (FIRQ). If FIRQ enabled, for interrupts
@@ -156,6 +162,10 @@
other regs will be saved according to the number of register bank;
If FIRQ is disabled, the handle of interrupts with highest priority
will be same with other interrupts.
+ NOTE: we don't allow the configuration with FIRQ enabled and only one
+ interrupt priority level (so all interrupts are FIRQ). Such
+ configuration isn't supported in software and it is not beneficial
+ from the performance point of view.
config ARC_FIRQ_STACK
bool "Enable separate firq stack"
diff --git a/include/arch/arc/arch.h b/include/arch/arc/arch.h
index a7441f8..5eed07a 100644
--- a/include/arch/arc/arch.h
+++ b/include/arch/arc/arch.h
@@ -43,6 +43,40 @@
#endif
#endif
+#if defined(CONFIG_ARC_FIRQ) && defined(CONFIG_ISA_ARCV3)
+#error "Unsupported configuration: ARC_FIRQ and ISA_ARCV3"
+#endif
+
+/*
+ * We don't allow the configuration with FIRQ enabled and only one interrupt priority level
+ * (so all interrupts are FIRQ). Such configuration isn't supported in software and it is not
+ * beneficial from the performance point of view.
+ */
+#if defined(CONFIG_ARC_FIRQ) && CONFIG_NUM_IRQ_PRIO_LEVELS < 2
+#error "Unsupported configuration: ARC_FIRQ and (NUM_IRQ_PRIO_LEVELS < 2)"
+#endif
+
+#if CONFIG_RGF_NUM_BANKS > 1 && !defined(CONFIG_ARC_FIRQ)
+#error "Unsupported configuration: (RGF_NUM_BANKS > 1) and !ARC_FIRQ"
+#endif
+
+/*
+ * It's required to have more than one interrupt priority level to use second register bank
+ * - otherwise all interrupts will use same register bank. Such configuration isn't supported in
+ * software and it is not beneficial from the performance point of view.
+ */
+#if CONFIG_RGF_NUM_BANKS > 1 && CONFIG_NUM_IRQ_PRIO_LEVELS < 2
+#error "Unsupported configuration: (RGF_NUM_BANKS > 1) and (NUM_IRQ_PRIO_LEVELS < 2)"
+#endif
+
+#if defined(CONFIG_ARC_FIRQ_STACK) && !defined(CONFIG_ARC_FIRQ)
+#error "Unsupported configuration: ARC_FIRQ_STACK and !ARC_FIRQ"
+#endif
+
+#if defined(CONFIG_ARC_FIRQ_STACK) && CONFIG_RGF_NUM_BANKS < 2
+#error "Unsupported configuration: ARC_FIRQ_STACK and (RGF_NUM_BANKS < 2)"
+#endif
+
#ifndef _ASMLANGUAGE
#ifdef __cplusplus
