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153 lines
4.3 KiB
Diff
153 lines
4.3 KiB
Diff
From 77612720a2362230af726baa4149c40ec7a7fb05 Mon Sep 17 00:00:00 2001
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From: Sricharan R <sricharan@codeaurora.org>
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Date: Tue, 14 Aug 2018 17:42:31 +0530
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Subject: [PATCH 12/12] clk: qcom: Add safe switch hook for krait mux clocks
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When the Hfplls are reprogrammed during the rate change,
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the primary muxes which are sourced from the same hfpll
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for higher frequencies, needs to be switched to the 'safe
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secondary mux' as the parent for that small window. This
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is done by registering a clk notifier for the muxes and
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switching to the safe parent in the PRE_RATE_CHANGE notifier
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and back to the original parent in the POST_RATE_CHANGE notifier.
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Signed-off-by: Sricharan R <sricharan@codeaurora.org>
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Tested-by: Craig Tatlor <ctatlor97@gmail.com>
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Signed-off-by: Stephen Boyd <sboyd@kernel.org>
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---
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drivers/clk/qcom/clk-krait.c | 2 ++
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drivers/clk/qcom/clk-krait.h | 3 ++
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drivers/clk/qcom/krait-cc.c | 56 ++++++++++++++++++++++++++++++++++++
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3 files changed, 61 insertions(+)
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--- a/drivers/clk/qcom/clk-krait.c
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+++ b/drivers/clk/qcom/clk-krait.c
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@@ -50,6 +50,8 @@ static int krait_mux_set_parent(struct c
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if (__clk_is_enabled(hw->clk))
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__krait_mux_set_sel(mux, sel);
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+ mux->reparent = true;
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+
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return 0;
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}
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--- a/drivers/clk/qcom/clk-krait.h
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+++ b/drivers/clk/qcom/clk-krait.h
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@@ -12,6 +12,9 @@ struct krait_mux_clk {
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u32 shift;
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u32 en_mask;
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bool lpl;
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+ u8 safe_sel;
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+ u8 old_index;
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+ bool reparent;
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struct clk_hw hw;
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struct notifier_block clk_nb;
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--- a/drivers/clk/qcom/krait-cc.c
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+++ b/drivers/clk/qcom/krait-cc.c
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@@ -26,6 +26,49 @@ static unsigned int pri_mux_map[] = {
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0,
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};
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+/*
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+ * Notifier function for switching the muxes to safe parent
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+ * while the hfpll is getting reprogrammed.
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+ */
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+static int krait_notifier_cb(struct notifier_block *nb,
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+ unsigned long event,
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+ void *data)
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+{
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+ int ret = 0;
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+ struct krait_mux_clk *mux = container_of(nb, struct krait_mux_clk,
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+ clk_nb);
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+ /* Switch to safe parent */
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+ if (event == PRE_RATE_CHANGE) {
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+ mux->old_index = krait_mux_clk_ops.get_parent(&mux->hw);
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+ ret = krait_mux_clk_ops.set_parent(&mux->hw, mux->safe_sel);
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+ mux->reparent = false;
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+ /*
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+ * By the time POST_RATE_CHANGE notifier is called,
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+ * clk framework itself would have changed the parent for the new rate.
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+ * Only otherwise, put back to the old parent.
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+ */
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+ } else if (event == POST_RATE_CHANGE) {
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+ if (!mux->reparent)
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+ ret = krait_mux_clk_ops.set_parent(&mux->hw,
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+ mux->old_index);
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+ }
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+
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+ return notifier_from_errno(ret);
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+}
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+
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+static int krait_notifier_register(struct device *dev, struct clk *clk,
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+ struct krait_mux_clk *mux)
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+{
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+ int ret = 0;
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+
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+ mux->clk_nb.notifier_call = krait_notifier_cb;
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+ ret = clk_notifier_register(clk, &mux->clk_nb);
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+ if (ret)
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+ dev_err(dev, "failed to register clock notifier: %d\n", ret);
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+
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+ return ret;
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+}
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+
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static int
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krait_add_div(struct device *dev, int id, const char *s, unsigned int offset)
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{
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@@ -70,6 +113,7 @@ static int
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krait_add_sec_mux(struct device *dev, int id, const char *s,
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unsigned int offset, bool unique_aux)
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{
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+ int ret;
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struct krait_mux_clk *mux;
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static const char *sec_mux_list[] = {
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"acpu_aux",
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@@ -93,6 +137,7 @@ krait_add_sec_mux(struct device *dev, in
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mux->shift = 2;
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mux->parent_map = sec_mux_map;
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mux->hw.init = &init;
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+ mux->safe_sel = 0;
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init.name = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
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if (!init.name)
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@@ -108,6 +153,11 @@ krait_add_sec_mux(struct device *dev, in
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clk = devm_clk_register(dev, &mux->hw);
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+ ret = krait_notifier_register(dev, clk, mux);
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+ if (ret)
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+ goto unique_aux;
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+
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+unique_aux:
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if (unique_aux)
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kfree(sec_mux_list[0]);
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err_aux:
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@@ -119,6 +169,7 @@ static struct clk *
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krait_add_pri_mux(struct device *dev, int id, const char *s,
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unsigned int offset)
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{
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+ int ret;
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struct krait_mux_clk *mux;
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const char *p_names[3];
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struct clk_init_data init = {
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@@ -139,6 +190,7 @@ krait_add_pri_mux(struct device *dev, in
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mux->lpl = id >= 0;
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mux->parent_map = pri_mux_map;
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mux->hw.init = &init;
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+ mux->safe_sel = 2;
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init.name = kasprintf(GFP_KERNEL, "krait%s_pri_mux", s);
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if (!init.name)
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@@ -164,6 +216,10 @@ krait_add_pri_mux(struct device *dev, in
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clk = devm_clk_register(dev, &mux->hw);
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+ ret = krait_notifier_register(dev, clk, mux);
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+ if (ret)
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+ goto err_p3;
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+err_p3:
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kfree(p_names[2]);
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err_p2:
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kfree(p_names[1]);
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