SPARC/LEON: added support for IRQAMP IRQ Controller

Needed for LEON AMP systems where different CPUs are routed to

different IRQ controllers. This patch selects the IRQ Controller
which has been routed to the boot CPU, it is up to the boot loader
to configure the IRQ controller.

Signed-off-by: Daniel Hellstrom <daniel@gaisler.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

arch/sparc/include/asm/leon.h

@@ -224,6 +224,18 @@ static inline void sparc_leon3_disable_cache(void)
 			  "sta %%l2, [%%g0] 2\n\t" : : : "l1", "l2");
 };
 
+static inline unsigned long sparc_leon3_asr17(void)
+{
+	u32 asr17;
+	__asm__ __volatile__ ("rd %%asr17, %0\n\t" : "=r"(asr17));
+	return asr17;
+};
+
+static inline int sparc_leon3_cpuid(void)
+{
+	return sparc_leon3_asr17() >> 28;
+}
+
 #endif /*!__ASSEMBLY__*/
 
 #ifdef CONFIG_SMP

arch/sparc/include/asm/leon_amba.h

@@ -100,9 +100,8 @@ struct leon3_irqctrl_regs_map {
 	u32 mpbroadcast;
 	u32 notused02;
 	u32 notused03;
-	u32 notused10;
-	u32 notused11;
-	u32 notused12;
+	u32 ampctrl;
+	u32 icsel[2];
 	u32 notused13;
 	u32 notused20;
 	u32 notused21;
@@ -112,6 +111,7 @@ struct leon3_irqctrl_regs_map {
 	u32 force[16];
 	/* Extended IRQ registers */
 	u32 intid[16];	/* 0xc0 */
+	u32 unused[(0x1000-0x100)/4];
 };
 
 struct leon3_apbuart_regs_map {

arch/sparc/kernel/leon_kernel.c

@@ -108,6 +108,7 @@ void __init leon_init_timers(irq_handler_t counter_fn)
 	struct device_node *rootnp, *np;
 	struct property *pp;
 	int len;
+	int cpu, icsel;
 
 	leondebug_irq_disable = 0;
 	leon_debug_irqout = 0;
@@ -160,6 +161,19 @@ void __init leon_init_timers(irq_handler_t counter_fn)
 		LEON3_BYPASS_STORE_PA(&leon3_gptimer_regs->e[1].ctrl, 0);
 # endif
 
+		/*
+		 * The IRQ controller may (if implemented) consist of multiple
+		 * IRQ controllers, each mapped on a 4Kb boundary.
+		 * Each CPU may be routed to different IRQCTRLs, however
+		 * we assume that all CPUs (in SMP system) is routed to the
+		 * same IRQ Controller, and for non-SMP only one IRQCTRL is
+		 * accessed anyway.
+		 * In AMP systems, Linux must run on CPU0 for the time being.
+		 */
+		cpu = sparc_leon3_cpuid();
+		icsel = LEON3_BYPASS_LOAD_PA(&leon3_irqctrl_regs->icsel[cpu/8]);
+		icsel = (icsel >> ((7 - (cpu&0x7)) * 4)) & 0xf;
+		leon3_irqctrl_regs += icsel;
 	} else {
 		goto bad;
 	}