linux-kernel - [PATCH 12/16] clk: qcom: clk-krait: add 8064 errata workaround

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Message-Id: <20220313190419.2207-13-ansuelsmth@gmail.com>
Date:   Sun, 13 Mar 2022 20:04:15 +0100
From:   Ansuel Smith <ansuelsmth@...il.com>
To:     Rob Herring <robh+dt@...nel.org>,
        Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        Prashant Gaikwad <pgaikwad@...dia.com>,
        Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Ansuel Smith <ansuelsmth@...il.com>,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-tegra@...r.kernel.org
Subject: [PATCH 12/16] clk: qcom: clk-krait: add 8064 errata workaround

Add 8064 errata workaround where the sec_src clock gating needs to be
disabled during switching. To enable this set disable_sec_src_gating in
the mux struct.

Signed-off-by: Ansuel Smith <ansuelsmth@...il.com>
---
 drivers/clk/qcom/clk-krait.c | 16 ++++++++++++++++
 drivers/clk/qcom/clk-krait.h |  1 +
 drivers/clk/qcom/krait-cc.c  |  1 +
 3 files changed, 18 insertions(+)

diff --git a/drivers/clk/qcom/clk-krait.c b/drivers/clk/qcom/clk-krait.c
index d8af281eba0e..82fe7031e1f4 100644
--- a/drivers/clk/qcom/clk-krait.c
+++ b/drivers/clk/qcom/clk-krait.c
@@ -18,13 +18,23 @@
 static DEFINE_SPINLOCK(krait_clock_reg_lock);
 
 #define LPL_SHIFT	8
+#define SECCLKAGD	BIT(4)
+
 static void __krait_mux_set_sel(struct krait_mux_clk *mux, int sel)
 {
 	unsigned long flags;
 	u32 regval;
 
 	spin_lock_irqsave(&krait_clock_reg_lock, flags);
+
 	regval = krait_get_l2_indirect_reg(mux->offset);
+
+	/* 8064 Errata: disable sec_src clock gating during switch. */
+	if (mux->disable_sec_src_gating) {
+		regval |= SECCLKAGD;
+		krait_set_l2_indirect_reg(mux->offset, regval);
+	}
+
 	regval &= ~(mux->mask << mux->shift);
 	regval |= (sel & mux->mask) << mux->shift;
 	if (mux->lpl) {
@@ -33,6 +43,12 @@ static void __krait_mux_set_sel(struct krait_mux_clk *mux, int sel)
 	}
 	krait_set_l2_indirect_reg(mux->offset, regval);
 
+	/* 8064 Errata: re-enabled sec_src clock gating. */
+	if (mux->disable_sec_src_gating) {
+		regval &= ~SECCLKAGD;
+		krait_set_l2_indirect_reg(mux->offset, regval);
+	}
+
 	/* Wait for switch to complete. */
 	mb();
 	udelay(1);
diff --git a/drivers/clk/qcom/clk-krait.h b/drivers/clk/qcom/clk-krait.h
index 9120bd2f5297..f930538c539e 100644
--- a/drivers/clk/qcom/clk-krait.h
+++ b/drivers/clk/qcom/clk-krait.h
@@ -15,6 +15,7 @@ struct krait_mux_clk {
 	u8		safe_sel;
 	u8		old_index;
 	bool		reparent;
+	bool		disable_sec_src_gating;
 
 	struct clk_hw	hw;
 	struct notifier_block   clk_nb;
diff --git a/drivers/clk/qcom/krait-cc.c b/drivers/clk/qcom/krait-cc.c
index 1bdc89c097e6..533a770332be 100644
--- a/drivers/clk/qcom/krait-cc.c
+++ b/drivers/clk/qcom/krait-cc.c
@@ -154,6 +154,7 @@ krait_add_sec_mux(struct device *dev, struct clk *qsb, int id,
 	mux->shift = 2;
 	mux->parent_map = sec_mux_map;
 	mux->hw.init = &init;
+	mux->disable_sec_src_gating = true;
 
 	init.name = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
 	if (!init.name)
-- 
2.34.1