diff options
Diffstat (limited to 'target/linux/ipq806x/patches-4.4/136-clk-Add-safe-switch-hook.patch')
| -rw-r--r-- | target/linux/ipq806x/patches-4.4/136-clk-Add-safe-switch-hook.patch | 158 |
1 files changed, 158 insertions, 0 deletions
diff --git a/target/linux/ipq806x/patches-4.4/136-clk-Add-safe-switch-hook.patch b/target/linux/ipq806x/patches-4.4/136-clk-Add-safe-switch-hook.patch new file mode 100644 index 0000000000..e969f6bca4 --- /dev/null +++ b/target/linux/ipq806x/patches-4.4/136-clk-Add-safe-switch-hook.patch @@ -0,0 +1,158 @@ +From f7a00ea959be31f9b742042294a359d508edce94 Mon Sep 17 00:00:00 2001 +From: Stephen Boyd <sboyd@codeaurora.org> +Date: Fri, 20 Mar 2015 23:45:23 -0700 +Subject: [PATCH] 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' 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: Ram Chandra Jangir <rjangi@codeaurora.org> +--- + drivers/clk/clk.c | 61 ++++++++++++++++++++++++++++++++++++++------ + include/linux/clk-provider.h | 1 + + 2 files changed, 54 insertions(+), 8 deletions(-) + +diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c +index 8404c3c..a29319a 100644 +--- a/drivers/clk/clk.c ++++ b/drivers/clk/clk.c +@@ -51,9 +51,12 @@ 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; ++ struct clk_core *safe_parent; + struct clk_core *new_parent; + struct clk_core *new_child; + unsigned long flags; +@@ -1271,7 +1274,8 @@ 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; + + core->new_rate = new_rate; + core->new_parent = new_parent; +@@ -1281,6 +1285,18 @@ static void clk_calc_subtree(struct clk_core *core, unsigned long new_rate, + 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); ++ 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; ++ } ++ } else { ++ core->safe_parent = NULL; ++ } ++ + 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); +@@ -1393,14 +1409,43 @@ static struct clk_core *clk_propagate_rate_change(struct clk_core *core, + 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) ++ 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; + } + +@@ -1446,7 +1491,8 @@ clk_change_rate(struct clk_core *core, unsigned long best_parent_rate) + + old_rate = core->rate; + +- 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); + +@@ -1472,9 +1518,6 @@ clk_change_rate(struct clk_core *core, unsigned long best_parent_rate) + + core->rate = core->new_rate; + +- if (core->notifier_count && old_rate != core->rate) +- __clk_notify(core, POST_RATE_CHANGE, old_rate, core->rate); +- + if (core->flags & CLK_RECALC_NEW_RATES) + (void)clk_calc_new_rates(core, core->new_rate); + +@@ -1537,6 +1580,8 @@ static int clk_core_set_rate_nolock(struct clk_core *core, + + core->req_rate = req_rate; + ++ clk_propagate_rate_change(top, POST_RATE_CHANGE); ++ + return ret; + } + +diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h +index b6b17b5..5d49262 100644 +--- a/include/linux/clk-provider.h ++++ b/include/linux/clk-provider.h +@@ -202,6 +202,7 @@ 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); + int (*set_rate)(struct clk_hw *hw, unsigned long rate, + unsigned long parent_rate); + int (*set_rate_and_parent)(struct clk_hw *hw, +-- +2.7.2 + |