sh: intc - improve group support

This patch improves intc group support, ie it makes it possible to
group interrupts together and mask / unmask the entire group. This
also works with priorities, so setting a priority for an entire group
is also possible. This patch is needed to properly support certain
processors such as the 7780.

Fixes for NULL pointers in DECLARE_INTC_DESC() are also included.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

1 files changed, 73 insertions, 20 deletions

diff --git a/arch/sh/kernel/cpu/irq/intc.c b/arch/sh/kernel/cpu/irq/intc.c
index 626b4d8d7932..9345a7130e9e 100644
--- a/arch/sh/kernel/cpu/irq/intc.c
+++ b/arch/sh/kernel/cpu/irq/intc.c
@@ -244,13 +244,33 @@ static unsigned int __init intc_find_prio_handler(unsigned int width)
         return REG_FN_ERROR;
 }
 
+static intc_enum __init intc_grp_id(struct intc_desc *desc, intc_enum enum_id)
+{
+        struct intc_group *g = desc->groups;
+        unsigned int i, j;
+
+        for (i = 0; g && enum_id && i < desc->nr_groups; i++) {
+                g = desc->groups + i;
+
+                for (j = 0; g->enum_ids[j]; j++) {
+                        if (g->enum_ids[j] != enum_id)
+                                continue;
+
+                        return g->enum_id;
+                }
+        }
+
+        return 0;
+}
+
 static unsigned int __init intc_prio_value(struct intc_desc *desc,
-                                           intc_enum enum_id)
+                                           intc_enum enum_id, int do_grps)
 {
+        struct intc_prio *p = desc->priorities;
         unsigned int i;
 
-        for (i = 0; i < desc->nr_priorities; i++) {
-                struct intc_prio *p = desc->priorities + i;
+        for (i = 0; p && enum_id && i < desc->nr_priorities; i++) {
+                p = desc->priorities + i;
 
                 if (p->enum_id != enum_id)
                         continue;
@@ -258,16 +278,24 @@ static unsigned int __init intc_prio_value(struct intc_desc *desc,
                 return p->priority;
         }
 
-        return 1; /* default to the lowest priority if no priority is set */
+        if (do_grps)
+                return intc_prio_value(desc, intc_grp_id(desc, enum_id), 0);
+
+        /* default to the lowest priority possible if no priority is set
+         * - this needs to be at least 2 for 5-bit priorities on 7780
+         */
+
+        return 2;
 }
 
 static unsigned int __init intc_mask_data(struct intc_desc *desc,
-                                          intc_enum enum_id)
+                                          intc_enum enum_id, int do_grps)
 {
+        struct intc_mask_reg *mr = desc->mask_regs;
         unsigned int i, j, fn;
 
-        for (i = 0; i < desc->nr_mask_regs; i++) {
-                struct intc_mask_reg *mr = desc->mask_regs + i;
+        for (i = 0; mr && enum_id && i < desc->nr_mask_regs; i++) {
+                mr = desc->mask_regs + i;
 
                 for (j = 0; j < ARRAY_SIZE(mr->enum_ids); j++) {
                         if (mr->enum_ids[j] != enum_id)
@@ -281,16 +309,20 @@ static unsigned int __init intc_mask_data(struct intc_desc *desc,
                 }
         }
 
+        if (do_grps)
+                return intc_mask_data(desc, intc_grp_id(desc, enum_id), 0);
+
         return 0;
 }
 
 static unsigned int __init intc_prio_data(struct intc_desc *desc,
-                                          intc_enum enum_id)
+                                          intc_enum enum_id, int do_grps)
 {
+        struct intc_prio_reg *pr = desc->prio_regs;
         unsigned int i, j, fn, bit, prio;
 
-        for (i = 0; i < desc->nr_prio_regs; i++) {
-                struct intc_prio_reg *pr = desc->prio_regs + i;
+        for (i = 0; pr && enum_id && i < desc->nr_prio_regs; i++) {
+                pr = desc->prio_regs + i;
 
                 for (j = 0; j < ARRAY_SIZE(pr->enum_ids); j++) {
                         if (pr->enum_ids[j] != enum_id)
@@ -300,7 +332,7 @@ static unsigned int __init intc_prio_data(struct intc_desc *desc,
                         if (fn == REG_FN_ERROR)
                                 return 0;
 
-                        prio = intc_prio_value(desc, enum_id);
+                        prio = intc_prio_value(desc, enum_id, 1);
                         bit = pr->reg_width - ((j + 1) * pr->field_width);
 
                         BUG_ON(bit < 0);
@@ -309,27 +341,48 @@ static unsigned int __init intc_prio_data(struct intc_desc *desc,
                 }
         }
 
+        if (do_grps)
+                return intc_prio_data(desc, intc_grp_id(desc, enum_id), 0);
+
         return 0;
 }
 
 static void __init intc_register_irq(struct intc_desc *desc, intc_enum enum_id,
                                      unsigned int irq)
 {
-        unsigned int mask_data = intc_mask_data(desc, enum_id);
-        unsigned int prio_data = intc_prio_data(desc, enum_id);
-        unsigned int data = mask_data ? mask_data : prio_data;
+        unsigned int data[2], primary;
+
+        /* Prefer single interrupt source bitmap over other combinations:
+         * 1. bitmap, single interrupt source
+         * 2. priority, single interrupt source
+         * 3. bitmap, multiple interrupt sources (groups)
+         * 4. priority, multiple interrupt sources (groups)
+         */
 
-        BUG_ON(!data);
+        data[0] = intc_mask_data(desc, enum_id, 0);
+        data[1] = intc_prio_data(desc, enum_id, 0);
+
+        primary = 0;
+        if (!data[0] && data[1])
+                primary = 1;
+
+        data[0] = data[0] ? data[0] : intc_mask_data(desc, enum_id, 1);
+        data[1] = data[1] ? data[1] : intc_prio_data(desc, enum_id, 1);
+
+        if (!data[primary])
+                primary ^= 1;
+
+        BUG_ON(!data[primary]); /* must have primary masking method */
 
         disable_irq_nosync(irq);
         set_irq_chip_and_handler_name(irq, &desc->chip,
                                       handle_level_irq, "level");
-        set_irq_chip_data(irq, (void *)data);
-
-        /* set priority */
+        set_irq_chip_data(irq, (void *)data[primary]);
 
-        if (prio_data)
-                intc_reg_fns[_INTC_FN(prio_data)].enable(desc, prio_data);
+        /* enable secondary masking method if present */
+        if (data[!primary])
+                intc_reg_fns[_INTC_FN(data[!primary])].enable(desc,
+                                                              data[!primary]);
 
         /* irq should be disabled by default */
         desc->chip.mask(irq);