Patch "clk: renesas: rzg2l: Lock around writes to mux register" has been added to the 6.5-stable tree

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This is a note to let you know that I've just added the patch titled

    clk: renesas: rzg2l: Lock around writes to mux register

to the 6.5-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     clk-renesas-rzg2l-lock-around-writes-to-mux-register.patch
and it can be found in the queue-6.5 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 54252d2e3b99b1afb87ca15ed57f9db6b53fb814
Author: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
Date:   Fri Sep 29 08:38:50 2023 +0300

    clk: renesas: rzg2l: Lock around writes to mux register
    
    [ Upstream commit d2692ed490e680a41401cef879adebcfafb4298f ]
    
    The SD MUX output (SD0) is further divided by 4 in G2{L,UL}.  The
    divided clock is SD0_DIV4. SD0_DIV4 is registered with
    CLK_SET_RATE_PARENT which means a rate request for it is propagated to
    the MUX and could reach rzg2l_cpg_sd_clk_mux_set_parent() concurrently
    with the users of SD0.
    Add proper locking to avoid concurrent accesses on SD MUX set rate
    registers.
    
    Fixes: eaff33646f4cb ("clk: renesas: rzg2l: Add SDHI clk mux support")
    Signed-off-by: Claudiu Beznea <claudiu.beznea.uj@xxxxxxxxxxxxxx>
    Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
    Link: https://lore.kernel.org/r/20230929053915.1530607-4-claudiu.beznea@xxxxxxxxxxxxxx
    Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/clk/renesas/rzg2l-cpg.c b/drivers/clk/renesas/rzg2l-cpg.c
index 7245a34d43e0b..7be098315899c 100644
--- a/drivers/clk/renesas/rzg2l-cpg.c
+++ b/drivers/clk/renesas/rzg2l-cpg.c
@@ -196,6 +196,7 @@ static int rzg2l_cpg_sd_clk_mux_set_parent(struct clk_hw *hw, u8 index)
 	u32 shift = GET_SHIFT(hwdata->conf);
 	const u32 clk_src_266 = 2;
 	u32 msk, val, bitmask;
+	unsigned long flags;
 	int ret;
 
 	/*
@@ -211,23 +212,25 @@ static int rzg2l_cpg_sd_clk_mux_set_parent(struct clk_hw *hw, u8 index)
 	 */
 	bitmask = (GENMASK(GET_WIDTH(hwdata->conf) - 1, 0) << shift) << 16;
 	msk = off ? CPG_CLKSTATUS_SELSDHI1_STS : CPG_CLKSTATUS_SELSDHI0_STS;
+	spin_lock_irqsave(&priv->rmw_lock, flags);
 	if (index != clk_src_266) {
 		writel(bitmask | ((clk_src_266 + 1) << shift), priv->base + off);
 
-		ret = readl_poll_timeout(priv->base + CPG_CLKSTATUS, val,
-					 !(val & msk), 100,
-					 CPG_SDHI_CLK_SWITCH_STATUS_TIMEOUT_US);
-		if (ret) {
-			dev_err(priv->dev, "failed to switch clk source\n");
-			return ret;
-		}
+		ret = readl_poll_timeout_atomic(priv->base + CPG_CLKSTATUS, val,
+						!(val & msk), 10,
+						CPG_SDHI_CLK_SWITCH_STATUS_TIMEOUT_US);
+		if (ret)
+			goto unlock;
 	}
 
 	writel(bitmask | ((index + 1) << shift), priv->base + off);
 
-	ret = readl_poll_timeout(priv->base + CPG_CLKSTATUS, val,
-				 !(val & msk), 100,
-				 CPG_SDHI_CLK_SWITCH_STATUS_TIMEOUT_US);
+	ret = readl_poll_timeout_atomic(priv->base + CPG_CLKSTATUS, val,
+					!(val & msk), 10,
+					CPG_SDHI_CLK_SWITCH_STATUS_TIMEOUT_US);
+unlock:
+	spin_unlock_irqrestore(&priv->rmw_lock, flags);
+
 	if (ret)
 		dev_err(priv->dev, "failed to switch clk source\n");
 
diff --git a/drivers/clk/renesas/rzg2l-cpg.h b/drivers/clk/renesas/rzg2l-cpg.h
index 6cee9e56acc72..91e9c2569f801 100644
--- a/drivers/clk/renesas/rzg2l-cpg.h
+++ b/drivers/clk/renesas/rzg2l-cpg.h
@@ -43,7 +43,7 @@
 #define CPG_CLKSTATUS_SELSDHI0_STS	BIT(28)
 #define CPG_CLKSTATUS_SELSDHI1_STS	BIT(29)
 
-#define CPG_SDHI_CLK_SWITCH_STATUS_TIMEOUT_US	20000
+#define CPG_SDHI_CLK_SWITCH_STATUS_TIMEOUT_US	200
 
 /* n = 0/1/2 for PLL1/4/6 */
 #define CPG_SAMPLL_CLK1(n)	(0x04 + (16 * n))



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