OF: MIPS: lantiq: implement irq_domain support

Add support for irq_domain on lantiq socs. The conversion is straight forward
as the ICU found inside the socs allows the usage of irq_domain_add_linear.

Harware IRQ 0->7 are the generic MIPS IRQs. 8->199 are the Lantiq IRQ Modules.
Our irq_chip callbacks need to substract 8 (MIPS_CPU_IRQ_CASCADE) from d->hwirq
to find out the correct offset into the Interrupt Modules register range.

Signed-off-by: John Crispin <blogic@openwrt.org>
Cc: devicetree-discuss@lists.ozlabs.org
Cc: Grant Likely <grant.likely@secretlab.ca>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/3802/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

1 files changed, 102 insertions, 76 deletions

diff --git a/arch/mips/lantiq/irq.c b/arch/mips/lantiq/irq.c
index d227be1c3c4d..57c1a4e51408 100644
--- a/arch/mips/lantiq/irq.c
+++ b/arch/mips/lantiq/irq.c
@@ -9,6 +9,11 @@
 
 #include <linux/interrupt.h>
 #include <linux/ioport.h>
+#include <linux/sched.h>
+#include <linux/irqdomain.h>
+#include <linux/of_platform.h>
+#include <linux/of_address.h>
+#include <linux/of_irq.h>
 
 #include <asm/bootinfo.h>
 #include <asm/irq_cpu.h>
@@ -16,7 +21,7 @@
 #include <lantiq_soc.h>
 #include <irq.h>
 
-/* register definitions */
+/* register definitions - internal irqs */
 #define LTQ_ICU_IM0_ISR         0x0000
 #define LTQ_ICU_IM0_IER         0x0008
 #define LTQ_ICU_IM0_IOSR        0x0010
@@ -25,6 +30,7 @@
 #define LTQ_ICU_IM1_ISR         0x0028
 #define LTQ_ICU_OFFSET          (LTQ_ICU_IM1_ISR - LTQ_ICU_IM0_ISR)
 
+/* register definitions - external irqs */
 #define LTQ_EIU_EXIN_C          0x0000
 #define LTQ_EIU_EXIN_INIC       0x0004
 #define LTQ_EIU_EXIN_INEN       0x000C
@@ -37,13 +43,14 @@
 #define LTQ_EIU_IR4             (INT_NUM_IM1_IRL0 + 1)
 #define LTQ_EIU_IR5             (INT_NUM_IM1_IRL0 + 2)
 #define LTQ_EIU_IR6             (INT_NUM_IM2_IRL0 + 30)
-
+#define XWAY_EXIN_COUNT         3
 #define MAX_EIU                 6
 
 /* the performance counter */
 #define LTQ_PERF_IRQ            (INT_NUM_IM4_IRL0 + 31)
 
-/* irqs generated by device attached to the EBU need to be acked in
+/*
+ * irqs generated by devices attached to the EBU need to be acked in
  * a special manner
  */
 #define LTQ_ICU_EBU_IRQ         22
@@ -58,6 +65,9 @@
 #define MIPS_CPU_IPI_RESCHED_IRQ        0
 #define MIPS_CPU_IPI_CALL_IRQ           1
 
+/* we have a cascade of 8 irqs */
+#define MIPS_CPU_IRQ_CASCADE            8
+
 #if defined(CONFIG_MIPS_MT_SMP) || defined(CONFIG_MIPS_MT_SMTC)
 int gic_present;
 #endif
@@ -71,64 +81,51 @@ static unsigned short ltq_eiu_irq[MAX_EIU] = {
         LTQ_EIU_IR5,
 };
 
-static struct resource ltq_icu_resource = {
-        .name   = "icu",
-        .start  = LTQ_ICU_BASE_ADDR,
-        .end    = LTQ_ICU_BASE_ADDR + LTQ_ICU_SIZE - 1,
-        .flags  = IORESOURCE_MEM,
-};
-
-static struct resource ltq_eiu_resource = {
-        .name   = "eiu",
-        .start  = LTQ_EIU_BASE_ADDR,
-        .end    = LTQ_EIU_BASE_ADDR + LTQ_ICU_SIZE - 1,
-        .flags  = IORESOURCE_MEM,
-};
-
+static int exin_avail;
 static void __iomem *ltq_icu_membase;
 static void __iomem *ltq_eiu_membase;
 
 void ltq_disable_irq(struct irq_data *d)
 {
         u32 ier = LTQ_ICU_IM0_IER;
-        int irq_nr = d->irq - INT_NUM_IRQ0;
+        int offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
 
-        ier += LTQ_ICU_OFFSET * (irq_nr / INT_NUM_IM_OFFSET);
-        irq_nr %= INT_NUM_IM_OFFSET;
-        ltq_icu_w32(ltq_icu_r32(ier) & ~(1 << irq_nr), ier);
+        ier += LTQ_ICU_OFFSET * (offset / INT_NUM_IM_OFFSET);
+        offset %= INT_NUM_IM_OFFSET;
+        ltq_icu_w32(ltq_icu_r32(ier) & ~BIT(offset), ier);
 }
 
 void ltq_mask_and_ack_irq(struct irq_data *d)
 {
         u32 ier = LTQ_ICU_IM0_IER;
         u32 isr = LTQ_ICU_IM0_ISR;
-        int irq_nr = d->irq - INT_NUM_IRQ0;
+        int offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
 
-        ier += LTQ_ICU_OFFSET * (irq_nr / INT_NUM_IM_OFFSET);
-        isr += LTQ_ICU_OFFSET * (irq_nr / INT_NUM_IM_OFFSET);
-        irq_nr %= INT_NUM_IM_OFFSET;
-        ltq_icu_w32(ltq_icu_r32(ier) & ~(1 << irq_nr), ier);
-        ltq_icu_w32((1 << irq_nr), isr);
+        ier += LTQ_ICU_OFFSET * (offset / INT_NUM_IM_OFFSET);
+        isr += LTQ_ICU_OFFSET * (offset / INT_NUM_IM_OFFSET);
+        offset %= INT_NUM_IM_OFFSET;
+        ltq_icu_w32(ltq_icu_r32(ier) & ~BIT(offset), ier);
+        ltq_icu_w32(BIT(offset), isr);
 }
 
 static void ltq_ack_irq(struct irq_data *d)
 {
         u32 isr = LTQ_ICU_IM0_ISR;
-        int irq_nr = d->irq - INT_NUM_IRQ0;
+        int offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
 
-        isr += LTQ_ICU_OFFSET * (irq_nr / INT_NUM_IM_OFFSET);
-        irq_nr %= INT_NUM_IM_OFFSET;
-        ltq_icu_w32((1 << irq_nr), isr);
+        isr += LTQ_ICU_OFFSET * (offset / INT_NUM_IM_OFFSET);
+        offset %= INT_NUM_IM_OFFSET;
+        ltq_icu_w32(BIT(offset), isr);
 }
 
 void ltq_enable_irq(struct irq_data *d)
 {
         u32 ier = LTQ_ICU_IM0_IER;
-        int irq_nr = d->irq - INT_NUM_IRQ0;
+        int offset = d->hwirq - MIPS_CPU_IRQ_CASCADE;
 
-        ier += LTQ_ICU_OFFSET  * (irq_nr / INT_NUM_IM_OFFSET);
-        irq_nr %= INT_NUM_IM_OFFSET;
-        ltq_icu_w32(ltq_icu_r32(ier) | (1 << irq_nr), ier);
+        ier += LTQ_ICU_OFFSET  * (offset / INT_NUM_IM_OFFSET);
+        offset %= INT_NUM_IM_OFFSET;
+        ltq_icu_w32(ltq_icu_r32(ier) | BIT(offset), ier);
 }
 
 static unsigned int ltq_startup_eiu_irq(struct irq_data *d)
@@ -137,15 +134,15 @@ static unsigned int ltq_startup_eiu_irq(struct irq_data *d)
 
         ltq_enable_irq(d);
         for (i = 0; i < MAX_EIU; i++) {
-                if (d->irq == ltq_eiu_irq[i]) {
+                if (d->hwirq == ltq_eiu_irq[i]) {
                         /* low level - we should really handle set_type */
                         ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_C) |
                                 (0x6 << (i * 4)), LTQ_EIU_EXIN_C);
                         /* clear all pending */
-                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INIC) & ~(1 << i),
+                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INIC) & ~BIT(i),
                                 LTQ_EIU_EXIN_INIC);
                         /* enable */
-                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) | (1 << i),
+                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) | BIT(i),
                                 LTQ_EIU_EXIN_INEN);
                         break;
                 }
@@ -160,9 +157,9 @@ static void ltq_shutdown_eiu_irq(struct irq_data *d)
 
         ltq_disable_irq(d);
         for (i = 0; i < MAX_EIU; i++) {
-                if (d->irq == ltq_eiu_irq[i]) {
+                if (d->hwirq == ltq_eiu_irq[i]) {
                         /* disable */
-                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) & ~(1 << i),
+                        ltq_eiu_w32(ltq_eiu_r32(LTQ_EIU_EXIN_INEN) & ~BIT(i),
                                 LTQ_EIU_EXIN_INEN);
                         break;
                 }
@@ -199,14 +196,15 @@ static void ltq_hw_irqdispatch(int module)
         if (irq == 0)
                 return;
 
-        /* silicon bug causes only the msb set to 1 to be valid. all
+        /*
+         * silicon bug causes only the msb set to 1 to be valid. all
          * other bits might be bogus
          */
         irq = __fls(irq);
-        do_IRQ((int)irq + INT_NUM_IM0_IRL0 + (INT_NUM_IM_OFFSET * module));
+        do_IRQ((int)irq + MIPS_CPU_IRQ_CASCADE + (INT_NUM_IM_OFFSET * module));
 
         /* if this is a EBU irq, we need to ack it or get a deadlock */
-        if ((irq == LTQ_ICU_EBU_IRQ) && (module == 0))
+        if ((irq == LTQ_ICU_EBU_IRQ) && (module == 0) && LTQ_EBU_PCC_ISTAT)
                 ltq_ebu_w32(ltq_ebu_r32(LTQ_EBU_PCC_ISTAT) | 0x10,
                         LTQ_EBU_PCC_ISTAT);
 }
@@ -290,38 +288,67 @@ out:
         return;
 }
 
+static int icu_map(struct irq_domain *d, unsigned int irq, irq_hw_number_t hw)
+{
+        struct irq_chip *chip = &ltq_irq_type;
+        int i;
+
+        for (i = 0; i < exin_avail; i++)
+                if (hw == ltq_eiu_irq[i])
+                        chip = &ltq_eiu_type;
+
+        irq_set_chip_and_handler(hw, chip, handle_level_irq);
+
+        return 0;
+}
+
+static const struct irq_domain_ops irq_domain_ops = {
+        .xlate = irq_domain_xlate_onetwocell,
+        .map = icu_map,
+};
+
 static struct irqaction cascade = {
         .handler = no_action,
         .name = "cascade",
 };
 
-void __init arch_init_irq(void)
+int __init icu_of_init(struct device_node *node, struct device_node *parent)
 {
+        struct device_node *eiu_node;
+        struct resource res;
         int i;
 
-        if (insert_resource(&iomem_resource, &ltq_icu_resource) < 0)
-                panic("Failed to insert icu memory");
+        if (of_address_to_resource(node, 0, &res))
+                panic("Failed to get icu memory range");
 
-        if (request_mem_region(ltq_icu_resource.start,
-                        resource_size(&ltq_icu_resource), "icu") < 0)
-                panic("Failed to request icu memory");
+        if (request_mem_region(res.start, resource_size(&res), res.name) < 0)
+                pr_err("Failed to request icu memory");
 
-        ltq_icu_membase = ioremap_nocache(ltq_icu_resource.start,
-                                resource_size(&ltq_icu_resource));
+        ltq_icu_membase = ioremap_nocache(res.start, resource_size(&res));
         if (!ltq_icu_membase)
                 panic("Failed to remap icu memory");
 
-        if (insert_resource(&iomem_resource, &ltq_eiu_resource) < 0)
-                panic("Failed to insert eiu memory");
-
-        if (request_mem_region(ltq_eiu_resource.start,
-                        resource_size(&ltq_eiu_resource), "eiu") < 0)
-                panic("Failed to request eiu memory");
-
-        ltq_eiu_membase = ioremap_nocache(ltq_eiu_resource.start,
-                                resource_size(&ltq_eiu_resource));
-        if (!ltq_eiu_membase)
-                panic("Failed to remap eiu memory");
+        /* the external interrupts are optional and xway only */
+        eiu_node = of_find_compatible_node(NULL, NULL, "lantiq,eiu");
+        if (eiu_node && of_address_to_resource(eiu_node, 0, &res)) {
+                /* find out how many external irq sources we have */
+                const __be32 *count = of_get_property(node,
+                                                        "lantiq,count", NULL);
+
+                if (count)
+                        exin_avail = *count;
+                if (exin_avail > MAX_EIU)
+                        exin_avail = MAX_EIU;
+
+                if (request_mem_region(res.start, resource_size(&res),
+                                                        res.name) < 0)
+                        pr_err("Failed to request eiu memory");
+
+                ltq_eiu_membase = ioremap_nocache(res.start,
+                                                        resource_size(&res));
+                if (!ltq_eiu_membase)
+                        panic("Failed to remap eiu memory");
+        }
 
         /* turn off all irqs by default */
         for (i = 0; i < 5; i++) {
@@ -346,20 +373,8 @@ void __init arch_init_irq(void)
                 set_vi_handler(7, ltq_hw5_irqdispatch);
         }
 
-        for (i = INT_NUM_IRQ0;
-                i <= (INT_NUM_IRQ0 + (5 * INT_NUM_IM_OFFSET)); i++)
-                if ((i == LTQ_EIU_IR0) || (i == LTQ_EIU_IR1) ||
-                        (i == LTQ_EIU_IR2))
-                        irq_set_chip_and_handler(i, &ltq_eiu_type,
-                                handle_level_irq);
-                /* EIU3-5 only exist on ar9 and vr9 */
-                else if (((i == LTQ_EIU_IR3) || (i == LTQ_EIU_IR4) ||
-                        (i == LTQ_EIU_IR5)) && (ltq_is_ar9() || ltq_is_vr9()))
-                        irq_set_chip_and_handler(i, &ltq_eiu_type,
-                                handle_level_irq);
-                else
-                        irq_set_chip_and_handler(i, &ltq_irq_type,
-                                handle_level_irq);
+        irq_domain_add_linear(node, 6 * INT_NUM_IM_OFFSET,
+                &irq_domain_ops, 0);
 
 #if defined(CONFIG_MIPS_MT_SMP)
         if (cpu_has_vint) {
@@ -382,9 +397,20 @@ void __init arch_init_irq(void)
 
         /* tell oprofile which irq to use */
         cp0_perfcount_irq = LTQ_PERF_IRQ;
+        return 0;
 }
 
 unsigned int __cpuinit get_c0_compare_int(void)
 {
         return CP0_LEGACY_COMPARE_IRQ;
 }
+
+static struct of_device_id __initdata of_irq_ids[] = {
+        { .compatible = "lantiq,icu", .data = icu_of_init },
+        {},
+};
+
+void __init arch_init_irq(void)
+{
+        of_irq_init(of_irq_ids);
+}