linux-kernel - [PATCH 02/14] clk: renesas: rzg2l-cpg: Check reset monitor registers

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Message-Id: <20231120070024.4079344-3-claudiu.beznea.uj@bp.renesas.com>
Date:   Mon, 20 Nov 2023 09:00:12 +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,
        linux@...linux.org.uk, geert+renesas@...der.be,
        magnus.damm@...il.com, mturquette@...libre.com, sboyd@...nel.org,
        linus.walleij@...aro.org, p.zabel@...gutronix.de, arnd@...db.de,
        m.szyprowski@...sung.com, alexandre.torgue@...s.st.com, afd@...com,
        broonie@...nel.org, alexander.stein@...tq-group.com,
        eugen.hristev@...labora.com, sergei.shtylyov@...il.com,
        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-arm-kernel@...ts.infradead.org, linux-clk@...r.kernel.org,
        linux-gpio@...r.kernel.org, claudiu.beznea@...on.dev,
        Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
Subject: [PATCH 02/14] clk: renesas: rzg2l-cpg: Check reset monitor registers

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

Hardware manual of both RZ/G2L and RZ/G3S specifies that 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 reset signal is
toggled leading to failures (on probe or resume from deep sleep states).

Fixes: ef3c613ccd68 ("clk: renesas: Add CPG core wrapper for RZ/G2L SoC")
Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@...renesas.com>
---

Hi, Geert,

In case you apply this patch and patch 1/13 as is, please add a Depend-on
tag on this patch to point to patch 1/13 for proper backporting.

Thank you,
Claudiu Beznea

 drivers/clk/renesas/rzg2l-cpg.c | 30 ++++++++++++++++++++++++------
 1 file changed, 24 insertions(+), 6 deletions(-)

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 3189c3167ba8..2922dc884e35 100644
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -1416,12 +1416,23 @@ 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 dis = BIT(info->resets[id].bit);
+	u32 value = dis << 16;
+	int ret = 0;
 
 	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) {
+		ret = readl_poll_timeout_atomic(priv->base + CLK_MRST_R(reg), value,
+						value & dis, 10, 200);
+	} else {
+		/* Wait for at least one cycle of the RCLK clock (@ ca. 32 kHz) */
+		udelay(35);
+	}
+
+	return ret;
 }
 
 static int rzg2l_cpg_deassert(struct reset_controller_dev *rcdev,
@@ -1432,12 +1443,22 @@ static int rzg2l_cpg_deassert(struct reset_controller_dev *rcdev,
 	unsigned int reg = info->resets[id].off;
 	u32 dis = BIT(info->resets[id].bit);
 	u32 value = (dis << 16) | dis;
+	int ret = 0;
 
 	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) {
+		ret = readl_poll_timeout_atomic(priv->base + CLK_MRST_R(reg), value,
+						!(value & dis), 10, 200);
+	} else {
+		/* Wait for at least one cycle of the RCLK clock (@ ca. 32 kHz) */
+		udelay(35);
+	}
+
+	return ret;
 }
 
 static int rzg2l_cpg_reset(struct reset_controller_dev *rcdev,
@@ -1449,9 +1470,6 @@ 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);
 }
 
-- 
2.39.2