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 #include #include -#include +#include #include #include #include @@ -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 #include #include +#include +#include #include #include 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; };