linux-kernel - [PATCH v2 01/11] clk: renesas: rzg2l-cpg: Check reset monitor registers

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Date:   Thu,  7 Dec 2023 09:06:50 +0200
From:   Claudiu <claudiu.beznea@...on.dev>
To:     s.shtylyov@....ru, davem@...emloft.net, edumazet@...gle.com,
        kuba@...nel.org, pabeni@...hat.com, robh+dt@...nel.org,
        krzysztof.kozlowski+dt@...aro.org, conor+dt@...nel.org,
        geert+renesas@...der.be, magnus.damm@...il.com,
        mturquette@...libre.com, sboyd@...nel.org,
        linus.walleij@...aro.org, prabhakar.mahadev-lad.rj@...renesas.com,
        biju.das.jz@...renesas.com
Cc:     linux-renesas-soc@...r.kernel.org, netdev@...r.kernel.org,
        devicetree@...r.kernel.org, linux-kernel@...r.kernel.org,
        linux-clk@...r.kernel.org, linux-gpio@...r.kernel.org,
        Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: [PATCH v2 01/11] clk: renesas: rzg2l-cpg: Check reset monitor registers

From: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>

The hardware manual of both RZ/G2L and RZ/G3S specifies that the reset
monitor registers need to be interrogated when the reset signals are
toggled (chapters "Procedures for Supplying and Stopping Reset Signals"
and "Procedure for Activating Modules"). Without this, there is a chance
that different modules (e.g., Ethernet) to not be ready after their reset
signal is toggled, leading to failures (on probe or resume from deep sleep
states).

The same indications are available for RZ/V2M for TYPE-B reset controls.

Fixes: ef3c613ccd68 ("clk: renesas: Add CPG core wrapper for RZ/G2L SoC")
Fixes: 8090bea32484 ("clk: renesas: rzg2l: Add support for RZ/V2M reset monitor reg")
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
---

Changes in v2:
- adapted for CPG versions with monbit (e.g., RZ/V2M)
- added a fixes tag for RZ/V2M
- fixed typos in commit description

 drivers/clk/renesas/rzg2l-cpg.c | 59 ++++++++++++++++++++++++---------
 1 file changed, 44 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 3189c3167ba8..1424fe78f09f 100644
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -1416,12 +1416,27 @@ static int rzg2l_cpg_assert(struct reset_controller_dev *rcdev,
 	struct rzg2l_cpg_priv *priv = rcdev_to_priv(rcdev);
 	const struct rzg2l_cpg_info *info = priv->info;
 	unsigned int reg = info->resets[id].off;
-	u32 value = BIT(info->resets[id].bit) << 16;
+	u32 mask = BIT(info->resets[id].bit);
+	s8 monbit = info->resets[id].monbit;
+	u32 value = mask << 16;
 
 	dev_dbg(rcdev->dev, "assert id:%ld offset:0x%x\n", id, CLK_RST_R(reg));
 
 	writel(value, priv->base + CLK_RST_R(reg));
-	return 0;
+
+	if (info->has_clk_mon_regs) {
+		reg = CLK_MRST_R(reg);
+	} else if (monbit >= 0) {
+		reg = CPG_RST_MON;
+		mask = BIT(monbit);
+	} else {
+		/* Wait for at least one cyc le of the RCLK clock (@ ca. 32 kHz) */
+		udelay(35);
+		return 0;
+	}
+
+	return readl_poll_timeout_atomic(priv->base + reg, value,
+					 value & mask, 10, 200);
 }
 
 static int rzg2l_cpg_deassert(struct reset_controller_dev *rcdev,
@@ -1430,14 +1445,28 @@ static int rzg2l_cpg_deassert(struct reset_controller_dev *rcdev,
 	struct rzg2l_cpg_priv *priv = rcdev_to_priv(rcdev);
 	const struct rzg2l_cpg_info *info = priv->info;
 	unsigned int reg = info->resets[id].off;
-	u32 dis = BIT(info->resets[id].bit);
-	u32 value = (dis << 16) | dis;
+	u32 mask = BIT(info->resets[id].bit);
+	s8 monbit = info->resets[id].monbit;
+	u32 value = (mask << 16) | mask;
 
 	dev_dbg(rcdev->dev, "deassert id:%ld offset:0x%x\n", id,
 		CLK_RST_R(reg));
 
 	writel(value, priv->base + CLK_RST_R(reg));
-	return 0;
+
+	if (info->has_clk_mon_regs) {
+		reg = CLK_MRST_R(reg);
+	} else if (monbit >= 0) {
+		reg = CPG_RST_MON;
+		mask = BIT(monbit);
+	} else {
+		/* Wait for at least one cycle of the RCLK clock (@ ca. 32 kHz) */
+		udelay(35);
+		return 0;
+	}
+
+	return readl_poll_timeout_atomic(priv->base + reg, value,
+					 !(value & mask), 10, 200);
 }
 
 static int rzg2l_cpg_reset(struct reset_controller_dev *rcdev,
@@ -1449,9 +1478,6 @@ static int rzg2l_cpg_reset(struct reset_controller_dev *rcdev,
 	if (ret)
 		return ret;
 
-	/* Wait for at least one cycle of the RCLK clock (@ ca. 32 kHz) */
-	udelay(35);
-
 	return rzg2l_cpg_deassert(rcdev, id);
 }
 
@@ -1460,18 +1486,21 @@ static int rzg2l_cpg_status(struct reset_controller_dev *rcdev,
 {
 	struct rzg2l_cpg_priv *priv = rcdev_to_priv(rcdev);
 	const struct rzg2l_cpg_info *info = priv->info;
-	unsigned int reg = info->resets[id].off;
-	u32 bitmask = BIT(info->resets[id].bit);
 	s8 monbit = info->resets[id].monbit;
+	unsigned int reg;
+	u32 bitmask;
 
 	if (info->has_clk_mon_regs) {
-		return !!(readl(priv->base + CLK_MRST_R(reg)) & bitmask);
+		reg = CLK_MRST_R(info->resets[id].off);
+		bitmask = BIT(info->resets[id].bit);
 	} else if (monbit >= 0) {
-		u32 monbitmask = BIT(monbit);
-
-		return !!(readl(priv->base + CPG_RST_MON) & monbitmask);
+		reg = CPG_RST_MON;
+		bitmask = BIT(monbit);
+	} else {
+		return -ENOTSUPP;
 	}
-	return -ENOTSUPP;
+
+	return !!(readl(priv->base + reg) & bitmask);
 }
 
 static const struct reset_control_ops rzg2l_cpg_reset_ops = {
-- 
2.39.2