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| author | Vineet Gupta <vgupta@synopsys.com> | 2016-09-30 16:13:28 -0700 |
|---|---|---|
| committer | Vineet Gupta <vgupta@synopsys.com> | 2016-12-14 09:23:46 -0800 |
| commit | 107177b14d8179f864315fc4daed9da777ed30c2 (patch) | |
| tree | bf549522914db856961b39e9e12e3fc8654db3d9 /arch/arc | |
| parent | 78833e79d516901413d6e9278cbebf6116d62c78 (diff) | |
| download | linux-107177b14d8179f864315fc4daed9da777ed30c2.tar.gz linux-107177b14d8179f864315fc4daed9da777ed30c2.tar.xz | |
ARCv2: intc: default all interrupts to priority 1
ARC HS Cores support configurable multiple interrupt priorities of upto
16 levels. In commit dec2b2849cfcc ("ARCv2: intc: Allow interruption by
lowest priority interrupt") we switched to 15 which seems a bit
excessive given that there would be rare hardware implementing so many
preemption levels AND running Linux. It would seem that 2 levels will be
more common so switch to 1 as the default priority level. This will be
the "lower" priority level saving 0 for implementing NMI style support.
This scheme also works in systems with more than 2 prioity levels as
well.
Signed-off-by: Vineet Gupta <vgupta@synopsys.com>
Diffstat (limited to 'arch/arc')
| -rw-r--r-- | arch/arc/include/asm/irqflags-arcv2.h | 6 | ||||
| -rw-r--r-- | arch/arc/kernel/intc-arcv2.c | 10 |
2 files changed, 7 insertions, 9 deletions
diff --git a/arch/arc/include/asm/irqflags-arcv2.h b/arch/arc/include/asm/irqflags-arcv2.h index e880dfa3fcd3..a64c447b0337 100644 --- a/arch/arc/include/asm/irqflags-arcv2.h +++ b/arch/arc/include/asm/irqflags-arcv2.h @@ -38,10 +38,10 @@ #define AUX_IRQ_ACT_BIT_U 31 /* - * User space should be interruptable even by lowest prio interrupt - * Safe even if actual interrupt priorities is fewer or even one + * Hardware supports 16 priorities (0 highest, 15 lowest) + * Linux by default runs at 1, priority 0 reserved for NMI style interrupts */ -#define ARCV2_IRQ_DEF_PRIO 15 +#define ARCV2_IRQ_DEF_PRIO 1 /* seed value for status register */ #define ISA_INIT_STATUS_BITS (STATUS_IE_MASK | STATUS_AD_MASK | \ diff --git a/arch/arc/kernel/intc-arcv2.c b/arch/arc/kernel/intc-arcv2.c index 62b59409a5d9..994dca7014db 100644 --- a/arch/arc/kernel/intc-arcv2.c +++ b/arch/arc/kernel/intc-arcv2.c @@ -14,8 +14,6 @@ #include <linux/irqchip.h> #include <asm/irq.h> -static int irq_prio; - /* * Early Hardware specific Interrupt setup * -Called very early (start_kernel -> setup_arch -> setup_processor) @@ -24,7 +22,7 @@ static int irq_prio; */ void arc_init_IRQ(void) { - unsigned int tmp; + unsigned int tmp, irq_prio; struct irq_build { #ifdef CONFIG_CPU_BIG_ENDIAN @@ -67,12 +65,12 @@ void arc_init_IRQ(void) irq_prio = irq_bcr.prio; /* Encoded as N-1 for N levels */ pr_info("archs-intc\t: %d priority levels (default %d)%s\n", - irq_prio + 1, irq_prio, + irq_prio + 1, ARCV2_IRQ_DEF_PRIO, irq_bcr.firq ? " FIRQ (not used)":""); /* setup status32, don't enable intr yet as kernel doesn't want */ tmp = read_aux_reg(0xa); - tmp |= STATUS_AD_MASK | (irq_prio << 1); + tmp |= STATUS_AD_MASK | (ARCV2_IRQ_DEF_PRIO << 1); tmp &= ~STATUS_IE_MASK; asm volatile("kflag %0 \n"::"r"(tmp)); } @@ -93,7 +91,7 @@ void arcv2_irq_enable(struct irq_data *data) { /* set default priority */ write_aux_reg(AUX_IRQ_SELECT, data->irq); - write_aux_reg(AUX_IRQ_PRIORITY, irq_prio); + write_aux_reg(AUX_IRQ_PRIORITY, ARCV2_IRQ_DEF_PRIO); /* * hw auto enables (linux unmask) all by default |