2 files changed, 99 insertions, 2 deletions

diff --git a/drivers/sh/clk.c b/drivers/sh/clk.c
index 661a801126ad..813d97cdad49 100644
--- a/drivers/sh/clk.c
+++ b/drivers/sh/clk.c
@@ -25,7 +25,7 @@
 #include <linux/sysdev.h>
 #include <linux/seq_file.h>
 #include <linux/err.h>
-#include <linux/platform_device.h>
+#include <linux/io.h>
 #include <linux/debugfs.h>
 #include <linux/cpufreq.h>
 #include <linux/clk.h>
@@ -251,8 +251,88 @@ void recalculate_root_clocks(void)
         }
 }
 
+static struct clk_mapping dummy_mapping;
+
+static struct clk *lookup_root_clock(struct clk *clk)
+{
+        while (clk->parent)
+                clk = clk->parent;
+
+        return clk;
+}
+
+static int clk_establish_mapping(struct clk *clk)
+{
+        struct clk_mapping *mapping = clk->mapping;
+
+        /*
+         * Propagate mappings.
+         */
+        if (!mapping) {
+                struct clk *clkp;
+
+                /*
+                 * dummy mapping for root clocks with no specified ranges
+                 */
+                if (!clk->parent) {
+                        clk->mapping = &dummy_mapping;
+                        return 0;
+                }
+
+                /*
+                 * If we're on a child clock and it provides no mapping of its
+                 * own, inherit the mapping from its root clock.
+                 */
+                clkp = lookup_root_clock(clk);
+                mapping = clkp->mapping;
+                BUG_ON(!mapping);
+        }
+
+        /*
+         * Establish initial mapping.
+         */
+        if (!mapping->base && mapping->phys) {
+                kref_init(&mapping->ref);
+
+                mapping->base = ioremap_nocache(mapping->phys, mapping->len);
+                if (unlikely(!mapping->base))
+                        return -ENXIO;
+        } else if (mapping->base) {
+                /*
+                 * Bump the refcount for an existing mapping
+                 */
+                kref_get(&mapping->ref);
+        }
+
+        clk->mapping = mapping;
+        return 0;
+}
+
+static void clk_destroy_mapping(struct kref *kref)
+{
+        struct clk_mapping *mapping;
+
+        mapping = container_of(kref, struct clk_mapping, ref);
+
+        iounmap(mapping->base);
+}
+
+static void clk_teardown_mapping(struct clk *clk)
+{
+        struct clk_mapping *mapping = clk->mapping;
+
+        /* Nothing to do */
+        if (mapping == &dummy_mapping)
+                return;
+
+        kref_put(&mapping->ref, clk_destroy_mapping);
+        clk->mapping = NULL;
+}
+
 int clk_register(struct clk *clk)
 {
+        int ret;
+
         if (clk == NULL || IS_ERR(clk))
                 return -EINVAL;
 
@@ -267,6 +347,10 @@ int clk_register(struct clk *clk)
         INIT_LIST_HEAD(&clk->children);
         clk->usecount = 0;
 
+        ret = clk_establish_mapping(clk);
+        if (unlikely(ret))
+                goto out_unlock;
+
         if (clk->parent)
                 list_add(&clk->sibling, &clk->parent->children);
         else
@@ -275,9 +359,11 @@ int clk_register(struct clk *clk)
         list_add(&clk->node, &clock_list);
         if (clk->ops && clk->ops->init)
                 clk->ops->init(clk);
+
+out_unlock:
         mutex_unlock(&clock_list_sem);
 
-        return 0;
+        return ret;
 }
 EXPORT_SYMBOL_GPL(clk_register);
 
@@ -286,6 +372,7 @@ void clk_unregister(struct clk *clk)
         mutex_lock(&clock_list_sem);
         list_del(&clk->sibling);
         list_del(&clk->node);
+        clk_teardown_mapping(clk);
         mutex_unlock(&clock_list_sem);
 }
 EXPORT_SYMBOL_GPL(clk_unregister);
diff --git a/include/linux/sh_clk.h b/include/linux/sh_clk.h
index ecdfea54a49e..8ae37707a4a4 100644
--- a/include/linux/sh_clk.h
+++ b/include/linux/sh_clk.h
@@ -4,11 +4,20 @@
 #include <linux/list.h>
 #include <linux/seq_file.h>
 #include <linux/cpufreq.h>
+#include <linux/types.h>
+#include <linux/kref.h>
 #include <linux/clk.h>
 #include <linux/err.h>
 
 struct clk;
 
+struct clk_mapping {
+        phys_addr_t             phys;
+        void __iomem            *base;
+        unsigned long           len;
+        struct kref             ref;
+};
+
 struct clk_ops {
         void (*init)(struct clk *clk);
         int (*enable)(struct clk *clk);
@@ -42,6 +51,7 @@ struct clk {
         unsigned long           arch_flags;
         void                    *priv;
         struct dentry           *dentry;
+        struct clk_mapping      *mapping;
         struct cpufreq_frequency_table *freq_table;
 };