linux-kernel - [PATCH v2 3/3] clk: qcom: clk-krait: add apq/ipq8064 errata workaround

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Message-Id: <20220430054458.31321-4-ansuelsmth@gmail.com>
Date:   Sat, 30 Apr 2022 07:44:58 +0200
From:   Ansuel Smith <ansuelsmth@...il.com>
To:     Bjorn Andersson <bjorn.andersson@...aro.org>,
        Andy Gross <agross@...nel.org>,
        Michael Turquette <mturquette@...libre.com>,
        Stephen Boyd <sboyd@...nel.org>,
        Sricharan R <sricharan@...eaurora.org>,
        linux-arm-msm@...r.kernel.org, linux-clk@...r.kernel.org,
        linux-kernel@...r.kernel.org
Cc:     Ansuel Smith <ansuelsmth@...il.com>
Subject: [PATCH v2 3/3] clk: qcom: clk-krait: add apq/ipq8064 errata workaround

Add apq/ipq8064 errata workaround where the sec_src clock gating needs to
be disabled during switching. krait-cc compatible is not enough to
handle this and limit this workaround to apq/ipq8064. We check machine
compatible to handle this.

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  |  8 ++++++++
 3 files changed, 25 insertions(+)

diff --git a/drivers/clk/qcom/clk-krait.c b/drivers/clk/qcom/clk-krait.c
index 90046428693c..45da736bd5f4 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);
+
+	/* apq/ipq8064 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);
 
+	/* apq/ipq8064 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 4d4b657d33c3..cfd961d5cc45 100644
--- a/drivers/clk/qcom/krait-cc.c
+++ b/drivers/clk/qcom/krait-cc.c
@@ -139,6 +139,14 @@ krait_add_sec_mux(struct device *dev, int id, const char *s,
 	mux->hw.init = &init;
 	mux->safe_sel = 0;
 
+	/* Checking for qcom,krait-cc-v1 or qcom,krait-cc-v2 is not
+	 * enough to limit this to apq/ipq8064. Directly check machine
+	 * compatible to correctly handle this errata.
+	 */
+	if (of_machine_is_compatible("qcom,ipq8064") ||
+	    of_machine_is_compatible("qcom,apq8064"))
+		mux->disable_sec_src_gating = true;
+
 	init.name = kasprintf(GFP_KERNEL, "krait%s_sec_mux", s);
 	if (!init.name)
 		return -ENOMEM;
-- 
2.34.1