OpenWrt – Blame information for rev 4

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4 office 1 From patchwork Fri Dec 8 09:42:28 2017
2 Content-Type: text/plain; charset="utf-8"
3 MIME-Version: 1.0
4 Content-Transfer-Encoding: 7bit
5 Subject: [v4,10/12] clk: qcom: Add safe switch hook for krait mux clocks
6 From: Sricharan R <sricharan@codeaurora.org>
7 X-Patchwork-Id: 10102057
8 Message-Id: <1512726150-7204-11-git-send-email-sricharan@codeaurora.org>
9 To: mturquette@baylibre.com, sboyd@codeaurora.org,
10 devicetree@vger.kernel.org, linux-pm@vger.kernel.org,
11 linux-arm-msm@vger.kernel.org, linux-kernel@vger.kernel.org,
12 viresh.kumar@linaro.org, linux-arm-kernel@lists.infradead.org
13 Cc: sricharan@codeaurora.org
14 Date: Fri, 8 Dec 2017 15:12:28 +0530
15  
16 When the Hfplls are reprogrammed during the rate change,
17 the primary muxes which are sourced from the same hfpll
18 for higher frequencies, needs to be switched to the 'safe
19 secondary mux' as the parent for that small window. This
20 is done by registering a clk notifier for the muxes and
21 switching to the safe parent in the PRE_RATE_CHANGE notifier
22 and back to the original parent in the POST_RATE_CHANGE notifier.
23  
24 Signed-off-by: Sricharan R <sricharan@codeaurora.org>
25 ---
26 drivers/clk/qcom/clk-krait.c | 2 ++
27 drivers/clk/qcom/clk-krait.h | 3 +++
28 drivers/clk/qcom/krait-cc.c | 56 ++++++++++++++++++++++++++++++++++++++++++++
29 3 files changed, 61 insertions(+)
30  
31 --- a/drivers/clk/qcom/clk-krait.c
32 +++ b/drivers/clk/qcom/clk-krait.c
33 @@ -60,6 +60,8 @@ static int krait_mux_set_parent(struct c
34 if (__clk_is_enabled(hw->clk))
35 __krait_mux_set_sel(mux, sel);
36  
37 + mux->reparent = true;
38 +
39 return 0;
40 }
41  
42 --- a/drivers/clk/qcom/clk-krait.h
43 +++ b/drivers/clk/qcom/clk-krait.h
44 @@ -23,6 +23,9 @@ struct krait_mux_clk {
45 u32 shift;
46 u32 en_mask;
47 bool lpl;
48 + u8 safe_sel;
49 + u8 old_index;
50 + bool reparent;
51  
52 struct clk_hw hw;
53 struct notifier_block clk_nb;
54 --- a/drivers/clk/qcom/krait-cc.c
55 +++ b/drivers/clk/qcom/krait-cc.c
56 @@ -35,6 +35,49 @@ static unsigned int pri_mux_map[] = {
57 0,
58 };
59  
60 +/*
61 + * Notifier function for switching the muxes to safe parent
62 + * while the hfpll is getting reprogrammed.
63 + */
64 +static int krait_notifier_cb(struct notifier_block *nb,
65 + unsigned long event,
66 + void *data)
67 +{
68 + int ret = 0;
69 + struct krait_mux_clk *mux = container_of(nb, struct krait_mux_clk,
70 + clk_nb);
71 + /* Switch to safe parent */
72 + if (event == PRE_RATE_CHANGE) {
73 + mux->old_index = krait_mux_clk_ops.get_parent(&mux->hw);
74 + ret = krait_mux_clk_ops.set_parent(&mux->hw, mux->safe_sel);
75 + mux->reparent = false;
76 + /*
77 + * By the time POST_RATE_CHANGE notifier is called,
78 + * clk framework itself would have changed the parent for the new rate.
79 + * Only otherwise, put back to the old parent.
80 + */
81 + } else if (event == POST_RATE_CHANGE) {
82 + if (!mux->reparent)
83 + ret = krait_mux_clk_ops.set_parent(&mux->hw,
84 + mux->old_index);
85 + }
86 +
87 + return notifier_from_errno(ret);
88 +}
89 +
90 +static int krait_notifier_register(struct device *dev, struct clk *clk,
91 + struct krait_mux_clk *mux)
92 +{
93 + int ret = 0;
94 +
95 + mux->clk_nb.notifier_call = krait_notifier_cb;
96 + ret = clk_notifier_register(clk, &mux->clk_nb);
97 + if (ret)
98 + dev_err(dev, "failed to register clock notifier: %d\n", ret);
99 +
100 + return ret;
101 +}
102 +
103 static int
104 krait_add_div(struct device *dev, int id, const char *s, unsigned int offset)
105 {
106 @@ -79,6 +122,7 @@ static int
107 krait_add_sec_mux(struct device *dev, int id, const char *s,
108 unsigned int offset, bool unique_aux)
109 {
110 + int ret;
111 struct krait_mux_clk *mux;
112 static const char *sec_mux_list[] = {
113 "acpu_aux",
114 @@ -102,6 +146,7 @@ krait_add_sec_mux(struct device *dev, in
115 mux->shift = 2;
116 mux->parent_map = sec_mux_map;
117 mux->hw.init = &init;
118 + mux->safe_sel = 0;
119  
120 init.name = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
121 if (!init.name)
122 @@ -117,6 +162,11 @@ krait_add_sec_mux(struct device *dev, in
123  
124 clk = devm_clk_register(dev, &mux->hw);
125  
126 + ret = krait_notifier_register(dev, clk, mux);
127 + if (ret)
128 + goto unique_aux;
129 +
130 +unique_aux:
131 if (unique_aux)
132 kfree(sec_mux_list[0]);
133 err_aux:
134 @@ -128,6 +178,7 @@ static struct clk *
135 krait_add_pri_mux(struct device *dev, int id, const char *s,
136 unsigned int offset)
137 {
138 + int ret;
139 struct krait_mux_clk *mux;
140 const char *p_names[3];
141 struct clk_init_data init = {
142 @@ -148,6 +199,7 @@ krait_add_pri_mux(struct device *dev, in
143 mux->lpl = id >= 0;
144 mux->parent_map = pri_mux_map;
145 mux->hw.init = &init;
146 + mux->safe_sel = 2;
147  
148 init.name = kasprintf(GFP_KERNEL, "krait%s_pri_mux", s);
149 if (!init.name)
150 @@ -173,6 +225,10 @@ krait_add_pri_mux(struct device *dev, in
151  
152 clk = devm_clk_register(dev, &mux->hw);
153  
154 + ret = krait_notifier_register(dev, clk, mux);
155 + if (ret)
156 + goto err_p3;
157 +err_p3:
158 kfree(p_names[2]);
159 err_p2:
160 kfree(p_names[1]);