1 files changed, 143 insertions, 25 deletions

diff --git a/drivers/irqchip/irq-crossbar.c b/drivers/irqchip/irq-crossbar.c
index 3d15d16a7088..85c2985d8bcb 100644
--- a/drivers/irqchip/irq-crossbar.c
+++ b/drivers/irqchip/irq-crossbar.c
@@ -15,22 +15,31 @@
 #include <linux/of_irq.h>
 #include <linux/slab.h>
 #include <linux/irqchip/arm-gic.h>
+#include <linux/irqchip/irq-crossbar.h>
 
 #define IRQ_FREE        -1
+#define IRQ_RESERVED    -2
+#define IRQ_SKIP        -3
 #define GIC_IRQ_START   32
 
-/*
+/**
+ * struct crossbar_device - crossbar device description
  * @int_max: maximum number of supported interrupts
+ * @safe_map: safe default value to initialize the crossbar
+ * @max_crossbar_sources: Maximum number of crossbar sources
  * @irq_map: array of interrupts to crossbar number mapping
  * @crossbar_base: crossbar base address
  * @register_offsets: offsets for each irq number
+ * @write: register write function pointer
  */
 struct crossbar_device {
         uint int_max;
+        uint safe_map;
+        uint max_crossbar_sources;
         uint *irq_map;
         void __iomem *crossbar_base;
         int *register_offsets;
-        void (*write) (int, int);
+        void (*write)(int, int);
 };
 
 static struct crossbar_device *cb;
@@ -50,11 +59,22 @@ static inline void crossbar_writeb(int irq_no, int cb_no)
         writeb(cb_no, cb->crossbar_base + cb->register_offsets[irq_no]);
 }
 
+static inline int get_prev_map_irq(int cb_no)
+{
+        int i;
+
+        for (i = cb->int_max - 1; i >= 0; i--)
+                if (cb->irq_map[i] == cb_no)
+                        return i;
+
+        return -ENODEV;
+}
+
 static inline int allocate_free_irq(int cb_no)
 {
         int i;
 
-        for (i = 0; i < cb->int_max; i++) {
+        for (i = cb->int_max - 1; i >= 0; i--) {
                 if (cb->irq_map[i] == IRQ_FREE) {
                         cb->irq_map[i] = cb_no;
                         return i;
@@ -64,19 +84,47 @@ static inline int allocate_free_irq(int cb_no)
         return -ENODEV;
 }
 
+static inline bool needs_crossbar_write(irq_hw_number_t hw)
+{
+        int cb_no;
+
+        if (hw > GIC_IRQ_START) {
+                cb_no = cb->irq_map[hw - GIC_IRQ_START];
+                if (cb_no != IRQ_RESERVED && cb_no != IRQ_SKIP)
+                        return true;
+        }
+
+        return false;
+}
+
 static int crossbar_domain_map(struct irq_domain *d, unsigned int irq,
                                irq_hw_number_t hw)
 {
-        cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]);
+        if (needs_crossbar_write(hw))
+                cb->write(hw - GIC_IRQ_START, cb->irq_map[hw - GIC_IRQ_START]);
+
         return 0;
 }
 
+/**
+ * crossbar_domain_unmap - unmap a crossbar<->irq connection
+ * @d: domain of irq to unmap
+ * @irq: virq number
+ *
+ * We do not maintain a use count of total number of map/unmap
+ * calls for a particular irq to find out if a irq can be really
+ * unmapped. This is because unmap is called during irq_dispose_mapping(irq),
+ * after which irq is anyways unusable. So an explicit map has to be called
+ * after that.
+ */
 static void crossbar_domain_unmap(struct irq_domain *d, unsigned int irq)
 {
         irq_hw_number_t hw = irq_get_irq_data(irq)->hwirq;
 
-        if (hw > GIC_IRQ_START)
+        if (needs_crossbar_write(hw)) {
                 cb->irq_map[hw - GIC_IRQ_START] = IRQ_FREE;
+                cb->write(hw - GIC_IRQ_START, cb->safe_map);
+        }
 }
 
 static int crossbar_domain_xlate(struct irq_domain *d,
@@ -85,18 +133,41 @@ static int crossbar_domain_xlate(struct irq_domain *d,
                                  unsigned long *out_hwirq,
                                  unsigned int *out_type)
 {
-        unsigned long ret;
+        int ret;
+        int req_num = intspec[1];
+        int direct_map_num;
+
+        if (req_num >= cb->max_crossbar_sources) {
+                direct_map_num = req_num - cb->max_crossbar_sources;
+                if (direct_map_num < cb->int_max) {
+                        ret = cb->irq_map[direct_map_num];
+                        if (ret == IRQ_RESERVED || ret == IRQ_SKIP) {
+                                /* We use the interrupt num as h/w irq num */
+                                ret = direct_map_num;
+                                goto found;
+                        }
+                }
+
+                pr_err("%s: requested crossbar number %d > max %d\n",
+                       __func__, req_num, cb->max_crossbar_sources);
+                return -EINVAL;
+        }
 
-        ret = allocate_free_irq(intspec[1]);
+        ret = get_prev_map_irq(req_num);
+        if (ret >= 0)
+                goto found;
 
-        if (IS_ERR_VALUE(ret))
+        ret = allocate_free_irq(req_num);
+
+        if (ret < 0)
                 return ret;
 
+found:
         *out_hwirq = ret + GIC_IRQ_START;
         return 0;
 }
 
-const struct irq_domain_ops routable_irq_domain_ops = {
+static const struct irq_domain_ops routable_irq_domain_ops = {
         .map = crossbar_domain_map,
         .unmap = crossbar_domain_unmap,
         .xlate = crossbar_domain_xlate
@@ -104,22 +175,36 @@ const struct irq_domain_ops routable_irq_domain_ops = {
 
 static int __init crossbar_of_init(struct device_node *node)
 {
-        int i, size, max, reserved = 0, entry;
+        int i, size, max = 0, reserved = 0, entry;
         const __be32 *irqsr;
+        int ret = -ENOMEM;
 
         cb = kzalloc(sizeof(*cb), GFP_KERNEL);
 
         if (!cb)
-                return -ENOMEM;
+                return ret;
 
         cb->crossbar_base = of_iomap(node, 0);
         if (!cb->crossbar_base)
-                goto err1;
+                goto err_cb;
+
+        of_property_read_u32(node, "ti,max-crossbar-sources",
+                             &cb->max_crossbar_sources);
+        if (!cb->max_crossbar_sources) {
+                pr_err("missing 'ti,max-crossbar-sources' property\n");
+                ret = -EINVAL;
+                goto err_base;
+        }
 
         of_property_read_u32(node, "ti,max-irqs", &max);
-        cb->irq_map = kzalloc(max * sizeof(int), GFP_KERNEL);
+        if (!max) {
+                pr_err("missing 'ti,max-irqs' property\n");
+                ret = -EINVAL;
+                goto err_base;
+        }
+        cb->irq_map = kcalloc(max, sizeof(int), GFP_KERNEL);
         if (!cb->irq_map)
-                goto err2;
+                goto err_base;
 
         cb->int_max = max;
 
@@ -137,15 +222,35 @@ static int __init crossbar_of_init(struct device_node *node)
                                                    i, &entry);
                         if (entry > max) {
                                 pr_err("Invalid reserved entry\n");
-                                goto err3;
+                                ret = -EINVAL;
+                                goto err_irq_map;
+                        }
+                        cb->irq_map[entry] = IRQ_RESERVED;
+                }
+        }
+
+        /* Skip irqs hardwired to bypass the crossbar */
+        irqsr = of_get_property(node, "ti,irqs-skip", &size);
+        if (irqsr) {
+                size /= sizeof(__be32);
+
+                for (i = 0; i < size; i++) {
+                        of_property_read_u32_index(node,
+                                                   "ti,irqs-skip",
+                                                   i, &entry);
+                        if (entry > max) {
+                                pr_err("Invalid skip entry\n");
+                                ret = -EINVAL;
+                                goto err_irq_map;
                         }
-                        cb->irq_map[entry] = 0;
+                        cb->irq_map[entry] = IRQ_SKIP;
                 }
         }
 
-        cb->register_offsets = kzalloc(max * sizeof(int), GFP_KERNEL);
+
+        cb->register_offsets = kcalloc(max, sizeof(int), GFP_KERNEL);
         if (!cb->register_offsets)
-                goto err3;
+                goto err_irq_map;
 
         of_property_read_u32(node, "ti,reg-size", &size);
 
@@ -161,7 +266,8 @@ static int __init crossbar_of_init(struct device_node *node)
                 break;
         default:
                 pr_err("Invalid reg-size property\n");
-                goto err4;
+                ret = -EINVAL;
+                goto err_reg_offset;
                 break;
         }
 
@@ -170,25 +276,37 @@ static int __init crossbar_of_init(struct device_node *node)
          * reserved irqs. so find and store the offsets once.
          */
         for (i = 0; i < max; i++) {
-                if (!cb->irq_map[i])
+                if (cb->irq_map[i] == IRQ_RESERVED)
                         continue;
 
                 cb->register_offsets[i] = reserved;
                 reserved += size;
         }
 
+        of_property_read_u32(node, "ti,irqs-safe-map", &cb->safe_map);
+        /* Initialize the crossbar with safe map to start with */
+        for (i = 0; i < max; i++) {
+                if (cb->irq_map[i] == IRQ_RESERVED ||
+                    cb->irq_map[i] == IRQ_SKIP)
+                        continue;
+
+                cb->write(i, cb->safe_map);
+        }
+
         register_routable_domain_ops(&routable_irq_domain_ops);
         return 0;
 
-err4:
+err_reg_offset:
         kfree(cb->register_offsets);
-err3:
+err_irq_map:
         kfree(cb->irq_map);
-err2:
+err_base:
         iounmap(cb->crossbar_base);
-err1:
+err_cb:
         kfree(cb);
-        return -ENOMEM;
+
+        cb = NULL;
+        return ret;
 }
 
 static const struct of_device_id crossbar_match[] __initconst = {