[PATCH v3 8/8] clk: clocking-wizard: Use separate notifier_block for each clock

[Shubhrajyoti Datta]

A struct notifier_block has a single 'next' pointer, so registering the
same instance to two different notification chains corrupts the linked
lists. Use a dedicated nb_axi for the s_axi_aclk notifier chain.

Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxx>
---

Changes in v3:
Split notifier into per-clock callbacks

 drivers/clk/xilinx/clk-xlnx-clock-wizard.c | 42 +++++++++++++++++-----
 1 file changed, 33 insertions(+), 9 deletions(-)

diff --git a/drivers/clk/xilinx/clk-xlnx-clock-wizard.c b/drivers/clk/xilinx/clk-xlnx-clock-wizard.c
index b16656a11f4b..cfad11593b2b 100644
--- a/drivers/clk/xilinx/clk-xlnx-clock-wizard.c
+++ b/drivers/clk/xilinx/clk-xlnx-clock-wizard.c
@@ -126,7 +126,8 @@ enum clk_wzrd_int_clks {
 /**
  * struct clk_wzrd - Clock wizard private data structure
  *
- * @nb:			Notifier block
+ * @nb:			Notifier block for clk_in1
+ * @nb_axi:		Notifier block for s_axi_aclk
  * @base:		Memory base
  * @clk_in1:		Handle to input clock 'clk_in1'
  * @axi_clk:		Handle to input clock 's_axi_aclk'
@@ -137,6 +138,7 @@ enum clk_wzrd_int_clks {
  */
 struct clk_wzrd {
 	struct notifier_block nb;
+	struct notifier_block nb_axi;
 	void __iomem *base;
 	struct clk *clk_in1;
 	struct clk *axi_clk;
@@ -184,6 +186,7 @@ struct versal_clk_data {
 };
 
 #define to_clk_wzrd(_nb) container_of(_nb, struct clk_wzrd, nb)
+#define to_clk_wzrd_axi(_nb) container_of(_nb, struct clk_wzrd, nb_axi)
 
 /* maximum frequencies for input/output clocks per speed grade */
 static const unsigned long clk_wzrd_max_freq[] = {
@@ -1024,6 +1027,30 @@ static struct clk_hw *clk_wzrd_register_divider(struct device *dev,
 
 static int clk_wzrd_clk_notifier(struct notifier_block *nb, unsigned long event,
 				 void *data)
+{
+	unsigned long max;
+	struct clk_notifier_data *ndata = data;
+	struct clk_wzrd *clk_wzrd = to_clk_wzrd_axi(nb);
+
+	if (clk_wzrd->suspended)
+		return NOTIFY_OK;
+
+	max = WZRD_ACLK_MAX_FREQ;
+
+	switch (event) {
+	case PRE_RATE_CHANGE:
+		if (ndata->new_rate > max)
+			return NOTIFY_BAD;
+		return NOTIFY_OK;
+	case POST_RATE_CHANGE:
+	case ABORT_RATE_CHANGE:
+	default:
+		return NOTIFY_DONE;
+	}
+}
+
+static int clk_wzrd_clk_notifier_in1(struct notifier_block *nb, unsigned long event,
+				     void *data)
 {
 	unsigned long max;
 	struct clk_notifier_data *ndata = data;
@@ -1032,12 +1059,7 @@ static int clk_wzrd_clk_notifier(struct notifier_block *nb, unsigned long event,
 	if (clk_wzrd->suspended)
 		return NOTIFY_OK;
 
-	if (ndata->clk == clk_wzrd->clk_in1)
-		max = clk_wzrd_max_freq[clk_wzrd->speed_grade - 1];
-	else if (ndata->clk == clk_wzrd->axi_clk)
-		max = WZRD_ACLK_MAX_FREQ;
-	else
-		return NOTIFY_DONE;	/* should never happen */
+	max = clk_wzrd_max_freq[clk_wzrd->speed_grade - 1];
 
 	switch (event) {
 	case PRE_RATE_CHANGE:
@@ -1310,7 +1332,7 @@ static int clk_wzrd_probe(struct platform_device *pdev)
 		}
 
 		if (clk_wzrd->speed_grade) {
-			clk_wzrd->nb.notifier_call = clk_wzrd_clk_notifier;
+			clk_wzrd->nb.notifier_call = clk_wzrd_clk_notifier_in1;
 
 			ret = devm_clk_notifier_register(&pdev->dev, clk_wzrd->clk_in1,
 							 &clk_wzrd->nb);
@@ -1318,8 +1340,10 @@ static int clk_wzrd_probe(struct platform_device *pdev)
 				dev_warn(&pdev->dev,
 					 "unable to register clock notifier\n");
 
+			clk_wzrd->nb_axi.notifier_call = clk_wzrd_clk_notifier;
+
 			ret = devm_clk_notifier_register(&pdev->dev, clk_wzrd->axi_clk,
-							 &clk_wzrd->nb);
+							 &clk_wzrd->nb_axi);
 			if (ret)
 				dev_warn(&pdev->dev,
 					 "unable to register clock notifier\n");
-- 
2.34.1