Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752387Ab3G2L0X (ORCPT ); Mon, 29 Jul 2013 07:26:23 -0400 Received: from multi.imgtec.com ([194.200.65.239]:48083 "EHLO multi.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753924Ab3G2LZl (ORCPT ); Mon, 29 Jul 2013 07:25:41 -0400 From: James Hogan To: Mike Turquette , CC: Stephen Boyd , , Saravana Kannan , Doug Anderson , Sylwester Nawrocki , "James Hogan" Subject: [PATCH v6 2/5] clk: move some parent related functions upwards Date: Mon, 29 Jul 2013 12:24:59 +0100 Message-ID: <1375097102-28892-3-git-send-email-james.hogan@imgtec.com> X-Mailer: git-send-email 1.8.1.2 In-Reply-To: <1375097102-28892-1-git-send-email-james.hogan@imgtec.com> References: <1375097102-28892-1-git-send-email-james.hogan@imgtec.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [192.168.154.65] X-SEF-Processed: 7_3_0_01192__2013_07_29_12_25_40 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7306 Lines: 267 Move some parent related functions up in clk.c so they can be used by the modifications in the following patch which enables clock reparenting during set_rate. No other changes are made so this patch makes no functional difference in isolation. This is separate from the following patch primarily to ease readability of that patch. Signed-off-by: James Hogan Reviewed-by: Stephen Boyd Cc: Mike Turquette Cc: linux-arm-kernel@lists.infradead.org --- Changes in v5: * Rebased on latest clk-next ("clk: tegra: Use common of_clk_init function") Changes in v4: * new patch (patch 2) split out of patch 3 to avoid having to declare static __clk_set_parent() at the top of clk.c, and to ease readability of patch 3. drivers/clk/clk.c | 208 +++++++++++++++++++++++++++--------------------------- 1 file changed, 104 insertions(+), 104 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index e06a9ac..b766db1 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1027,6 +1027,110 @@ unsigned long clk_get_rate(struct clk *clk) } EXPORT_SYMBOL_GPL(clk_get_rate); +static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent) +{ + u8 i; + + if (!clk->parents) + clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents), + GFP_KERNEL); + + /* + * find index of new parent clock using cached parent ptrs, + * or if not yet cached, use string name comparison and cache + * them now to avoid future calls to __clk_lookup. + */ + for (i = 0; i < clk->num_parents; i++) { + if (clk->parents && clk->parents[i] == parent) + break; + else if (!strcmp(clk->parent_names[i], parent->name)) { + if (clk->parents) + clk->parents[i] = __clk_lookup(parent->name); + break; + } + } + + return i; +} + +static void clk_reparent(struct clk *clk, struct clk *new_parent) +{ + hlist_del(&clk->child_node); + + if (new_parent) + hlist_add_head(&clk->child_node, &new_parent->children); + else + hlist_add_head(&clk->child_node, &clk_orphan_list); + + clk->parent = new_parent; +} + +static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index) +{ + unsigned long flags; + int ret = 0; + struct clk *old_parent = clk->parent; + + /* + * Migrate prepare state between parents and prevent race with + * clk_enable(). + * + * If the clock is not prepared, then a race with + * clk_enable/disable() is impossible since we already have the + * prepare lock (future calls to clk_enable() need to be preceded by + * a clk_prepare()). + * + * If the clock is prepared, migrate the prepared state to the new + * parent and also protect against a race with clk_enable() by + * forcing the clock and the new parent on. This ensures that all + * future calls to clk_enable() are practically NOPs with respect to + * hardware and software states. + * + * See also: Comment for clk_set_parent() below. + */ + if (clk->prepare_count) { + __clk_prepare(parent); + clk_enable(parent); + clk_enable(clk); + } + + /* update the clk tree topology */ + flags = clk_enable_lock(); + clk_reparent(clk, parent); + clk_enable_unlock(flags); + + /* change clock input source */ + if (parent && clk->ops->set_parent) + ret = clk->ops->set_parent(clk->hw, p_index); + + if (ret) { + flags = clk_enable_lock(); + clk_reparent(clk, old_parent); + clk_enable_unlock(flags); + + if (clk->prepare_count) { + clk_disable(clk); + clk_disable(parent); + __clk_unprepare(parent); + } + return ret; + } + + /* + * Finish the migration of prepare state and undo the changes done + * for preventing a race with clk_enable(). + */ + if (clk->prepare_count) { + clk_disable(clk); + clk_disable(old_parent); + __clk_unprepare(old_parent); + } + + /* update debugfs with new clk tree topology */ + clk_debug_reparent(clk, parent); + return 0; +} + /** * __clk_speculate_rates * @clk: first clk in the subtree @@ -1334,18 +1438,6 @@ out: return ret; } -static void clk_reparent(struct clk *clk, struct clk *new_parent) -{ - hlist_del(&clk->child_node); - - if (new_parent) - hlist_add_head(&clk->child_node, &new_parent->children); - else - hlist_add_head(&clk->child_node, &clk_orphan_list); - - clk->parent = new_parent; -} - void __clk_reparent(struct clk *clk, struct clk *new_parent) { clk_reparent(clk, new_parent); @@ -1353,98 +1445,6 @@ void __clk_reparent(struct clk *clk, struct clk *new_parent) __clk_recalc_rates(clk, POST_RATE_CHANGE); } -static u8 clk_fetch_parent_index(struct clk *clk, struct clk *parent) -{ - u8 i; - - if (!clk->parents) - clk->parents = kzalloc((sizeof(struct clk*) * clk->num_parents), - GFP_KERNEL); - - /* - * find index of new parent clock using cached parent ptrs, - * or if not yet cached, use string name comparison and cache - * them now to avoid future calls to __clk_lookup. - */ - for (i = 0; i < clk->num_parents; i++) { - if (clk->parents && clk->parents[i] == parent) - break; - else if (!strcmp(clk->parent_names[i], parent->name)) { - if (clk->parents) - clk->parents[i] = __clk_lookup(parent->name); - break; - } - } - - return i; -} - -static int __clk_set_parent(struct clk *clk, struct clk *parent, u8 p_index) -{ - unsigned long flags; - int ret = 0; - struct clk *old_parent = clk->parent; - - /* - * Migrate prepare state between parents and prevent race with - * clk_enable(). - * - * If the clock is not prepared, then a race with - * clk_enable/disable() is impossible since we already have the - * prepare lock (future calls to clk_enable() need to be preceded by - * a clk_prepare()). - * - * If the clock is prepared, migrate the prepared state to the new - * parent and also protect against a race with clk_enable() by - * forcing the clock and the new parent on. This ensures that all - * future calls to clk_enable() are practically NOPs with respect to - * hardware and software states. - * - * See also: Comment for clk_set_parent() below. - */ - if (clk->prepare_count) { - __clk_prepare(parent); - clk_enable(parent); - clk_enable(clk); - } - - /* update the clk tree topology */ - flags = clk_enable_lock(); - clk_reparent(clk, parent); - clk_enable_unlock(flags); - - /* change clock input source */ - if (parent && clk->ops->set_parent) - ret = clk->ops->set_parent(clk->hw, p_index); - - if (ret) { - flags = clk_enable_lock(); - clk_reparent(clk, old_parent); - clk_enable_unlock(flags); - - if (clk->prepare_count) { - clk_disable(clk); - clk_disable(parent); - __clk_unprepare(parent); - } - return ret; - } - - /* - * Finish the migration of prepare state and undo the changes done - * for preventing a race with clk_enable(). - */ - if (clk->prepare_count) { - clk_disable(clk); - clk_disable(old_parent); - __clk_unprepare(old_parent); - } - - /* update debugfs with new clk tree topology */ - clk_debug_reparent(clk, parent); - return 0; -} - /** * clk_set_parent - switch the parent of a mux clk * @clk: the mux clk whose input we are switching -- 1.8.1.2 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/