+++ /dev/null
-From a1adfb782789ae9b25c928dfe3d639288563a86c Mon Sep 17 00:00:00 2001
-From: Stephen Boyd <sboyd@codeaurora.org>
-Date: Fri, 20 Mar 2015 23:45:23 -0700
-Subject: [PATCH 37/69] clk: Add safe switch hook
-
-Sometimes clocks can't accept their parent source turning off
-while the source is reprogrammed to a different rate. Most
-notably CPU clocks require a way to switch away from the current
-PLL they're running on, reprogram that PLL to a new rate, and
-then switch back to the PLL with the new rate once they're done.
-Add a hook that drivers can implement allowing them to return a
-'safe parent' and 'safe frequency' that they can switch their
-parent to while the upstream source is reprogrammed to support
-this.
-
-Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
-Signed-off-by: Georgi Djakov <georgi.djakov@linaro.org>
----
- drivers/clk/clk.c | 73 +++++++++++++++++++++++++++++++++++++++++---
- include/linux/clk-provider.h | 2 ++
- 2 files changed, 70 insertions(+), 5 deletions(-)
-
---- a/drivers/clk/clk.c
-+++ b/drivers/clk/clk.c
-@@ -51,9 +51,13 @@ struct clk_core {
- struct clk_core **parents;
- u8 num_parents;
- u8 new_parent_index;
-+ u8 safe_parent_index;
- unsigned long rate;
- unsigned long req_rate;
-+ unsigned long old_rate;
- unsigned long new_rate;
-+ unsigned long safe_freq;
-+ struct clk_core *safe_parent;
- struct clk_core *new_parent;
- struct clk_core *new_child;
- unsigned long flags;
-@@ -1310,7 +1314,9 @@ out:
- static void clk_calc_subtree(struct clk_core *core, unsigned long new_rate,
- struct clk_core *new_parent, u8 p_index)
- {
-- struct clk_core *child;
-+ struct clk_core *child, *parent;
-+ struct clk_hw *parent_hw;
-+ unsigned long safe_freq = 0;
-
- core->new_rate = new_rate;
- core->new_parent = new_parent;
-@@ -1320,6 +1326,23 @@ static void clk_calc_subtree(struct clk_
- if (new_parent && new_parent != core->parent)
- new_parent->new_child = core;
-
-+ if (core->ops->get_safe_parent) {
-+ parent_hw = core->ops->get_safe_parent(core->hw, &safe_freq);
-+ if (parent_hw) {
-+ parent = parent_hw->core;
-+ p_index = clk_fetch_parent_index(core, parent);
-+ core->safe_parent_index = p_index;
-+ core->safe_parent = parent;
-+ if (safe_freq)
-+ core->safe_freq = safe_freq;
-+ else
-+ core->safe_freq = 0;
-+ }
-+ } else {
-+ core->safe_parent = NULL;
-+ core->safe_freq = 0;
-+ }
-+
- hlist_for_each_entry(child, &core->children, child_node) {
- child->new_rate = clk_recalc(child, new_rate);
- clk_calc_subtree(child, child->new_rate, NULL, 0);
-@@ -1432,14 +1455,51 @@ static struct clk_core *clk_propagate_ra
- unsigned long event)
- {
- struct clk_core *child, *tmp_clk, *fail_clk = NULL;
-+ struct clk_core *old_parent;
- int ret = NOTIFY_DONE;
-
-- if (core->rate == core->new_rate)
-+ if (core->rate == core->new_rate && event != POST_RATE_CHANGE)
- return NULL;
-
-+ switch (event) {
-+ case PRE_RATE_CHANGE:
-+ if (core->safe_parent) {
-+ if (core->safe_freq)
-+ core->ops->set_rate_and_parent(core->hw,
-+ core->safe_freq,
-+ core->safe_parent->rate,
-+ core->safe_parent_index);
-+ else
-+ core->ops->set_parent(core->hw,
-+ core->safe_parent_index);
-+ }
-+ core->old_rate = core->rate;
-+ break;
-+ case POST_RATE_CHANGE:
-+ if (core->safe_parent) {
-+ old_parent = __clk_set_parent_before(core,
-+ core->new_parent);
-+ if (core->ops->set_rate_and_parent) {
-+ core->ops->set_rate_and_parent(core->hw,
-+ core->new_rate,
-+ core->new_parent ?
-+ core->new_parent->rate : 0,
-+ core->new_parent_index);
-+ } else if (core->ops->set_parent) {
-+ core->ops->set_parent(core->hw,
-+ core->new_parent_index);
-+ }
-+ __clk_set_parent_after(core, core->new_parent,
-+ old_parent);
-+ }
-+ break;
-+ }
-+
- if (core->notifier_count) {
-- ret = __clk_notify(core, event, core->rate, core->new_rate);
-- if (ret & NOTIFY_STOP_MASK)
-+ if (event != POST_RATE_CHANGE || core->old_rate != core->rate)
-+ ret = __clk_notify(core, event, core->old_rate,
-+ core->new_rate);
-+ if (ret & NOTIFY_STOP_MASK && event != POST_RATE_CHANGE)
- fail_clk = core;
- }
-
-@@ -1495,7 +1555,8 @@ clk_change_rate(struct clk_core *core, u
- clk_enable_unlock(flags);
- }
-
-- if (core->new_parent && core->new_parent != core->parent) {
-+ if (core->new_parent && core->new_parent != core->parent &&
-+ !core->safe_parent) {
- old_parent = __clk_set_parent_before(core, core->new_parent);
- trace_clk_set_parent(core, core->new_parent);
-
-@@ -1601,6 +1662,8 @@ static int clk_core_set_rate_nolock(stru
-
- core->req_rate = req_rate;
-
-+ clk_propagate_rate_change(top, POST_RATE_CHANGE);
-+
- return 0;
- }
-
---- a/include/linux/clk-provider.h
-+++ b/include/linux/clk-provider.h
-@@ -206,6 +206,8 @@ struct clk_ops {
- struct clk_rate_request *req);
- int (*set_parent)(struct clk_hw *hw, u8 index);
- u8 (*get_parent)(struct clk_hw *hw);
-+ struct clk_hw *(*get_safe_parent)(struct clk_hw *hw,
-+ unsigned long *safe_freq);
- int (*set_rate)(struct clk_hw *hw, unsigned long rate,
- unsigned long parent_rate);
- int (*set_rate_and_parent)(struct clk_hw *hw,
projects / openwrt / staging / nbd.git / blobdiff