clk: sunxi-ng: Unregister clocks/resets when unbinding

Currently, unbinding a CCU driver unmaps the device's MMIO region, while
leaving its clocks/resets and their providers registered. This can cause
a page fault later when some clock operation tries to perform MMIO. Fix
this by separating the CCU initialization from the memory allocation,
and then using a devres callback to unregister the clocks and resets.

This also fixes a memory leak of the `struct ccu_reset`, and uses the
correct owner (the specific platform driver) for the clocks and resets.

Early OF clock providers are never unregistered, and limited error
handling is possible, so they are mostly unchanged. The error reporting
is made more consistent by moving the message inside of_sunxi_ccu_probe.

Signed-off-by: Samuel Holland <samuel@sholland.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://lore.kernel.org/r/20210901050526.45673-2-samuel@sholland.org

1 files changed, 75 insertions, 14 deletions

diff --git a/drivers/clk/sunxi-ng/ccu_common.c b/drivers/clk/sunxi-ng/ccu_common.c
index 2e20e650b6c0..88cb569e5835 100644
--- a/drivers/clk/sunxi-ng/ccu_common.c
+++ b/drivers/clk/sunxi-ng/ccu_common.c
@@ -7,6 +7,7 @@
 
 #include <linux/clk.h>
 #include <linux/clk-provider.h>
+#include <linux/device.h>
 #include <linux/iopoll.h>
 #include <linux/slab.h>
 
@@ -14,6 +15,11 @@
 #include "ccu_gate.h"
 #include "ccu_reset.h"
 
+struct sunxi_ccu {
+	const struct sunxi_ccu_desc	*desc;
+	struct ccu_reset		reset;
+};
+
 static DEFINE_SPINLOCK(ccu_lock);
 
 void ccu_helper_wait_for_lock(struct ccu_common *common, u32 lock)
@@ -79,12 +85,15 @@ int ccu_pll_notifier_register(struct ccu_pll_nb *pll_nb)
 				     &pll_nb->clk_nb);
 }
 
-int sunxi_ccu_probe(struct device_node *node, void __iomem *reg,
-		    const struct sunxi_ccu_desc *desc)
+static int sunxi_ccu_probe(struct sunxi_ccu *ccu, struct device *dev,
+			   struct device_node *node, void __iomem *reg,
+			   const struct sunxi_ccu_desc *desc)
 {
 	struct ccu_reset *reset;
 	int i, ret;
 
+	ccu->desc = desc;
+
 	for (i = 0; i < desc->num_ccu_clks; i++) {
 		struct ccu_common *cclk = desc->ccu_clks[i];
 
@@ -103,7 +112,10 @@ int sunxi_ccu_probe(struct device_node *node, void __iomem *reg,
 			continue;
 
 		name = hw->init->name;
-		ret = of_clk_hw_register(node, hw);
+		if (dev)
+			ret = clk_hw_register(dev, hw);
+		else
+			ret = of_clk_hw_register(node, hw);
 		if (ret) {
 			pr_err("Couldn't register clock %d - %s\n", i, name);
 			goto err_clk_unreg;
@@ -115,15 +127,10 @@ int sunxi_ccu_probe(struct device_node *node, void __iomem *reg,
 	if (ret)
 		goto err_clk_unreg;
 
-	reset = kzalloc(sizeof(*reset), GFP_KERNEL);
-	if (!reset) {
-		ret = -ENOMEM;
-		goto err_alloc_reset;
-	}
-
+	reset = &ccu->reset;
 	reset->rcdev.of_node = node;
 	reset->rcdev.ops = &ccu_reset_ops;
-	reset->rcdev.owner = THIS_MODULE;
+	reset->rcdev.owner = dev ? dev->driver->owner : THIS_MODULE;
 	reset->rcdev.nr_resets = desc->num_resets;
 	reset->base = reg;
 	reset->lock = &ccu_lock;
@@ -131,13 +138,11 @@ int sunxi_ccu_probe(struct device_node *node, void __iomem *reg,
 
 	ret = reset_controller_register(&reset->rcdev);
 	if (ret)
-		goto err_of_clk_unreg;
+		goto err_del_provider;
 
 	return 0;
 
-err_of_clk_unreg:
-	kfree(reset);
-err_alloc_reset:
+err_del_provider:
 	of_clk_del_provider(node);
 err_clk_unreg:
 	while (--i >= 0) {
@@ -149,3 +154,59 @@ err_clk_unreg:
 	}
 	return ret;
 }
+
+static void devm_sunxi_ccu_release(struct device *dev, void *res)
+{
+	struct sunxi_ccu *ccu = res;
+	const struct sunxi_ccu_desc *desc = ccu->desc;
+	int i;
+
+	reset_controller_unregister(&ccu->reset.rcdev);
+	of_clk_del_provider(dev->of_node);
+
+	for (i = 0; i < desc->hw_clks->num; i++) {
+		struct clk_hw *hw = desc->hw_clks->hws[i];
+
+		if (!hw)
+			continue;
+		clk_hw_unregister(hw);
+	}
+}
+
+int devm_sunxi_ccu_probe(struct device *dev, void __iomem *reg,
+			 const struct sunxi_ccu_desc *desc)
+{
+	struct sunxi_ccu *ccu;
+	int ret;
+
+	ccu = devres_alloc(devm_sunxi_ccu_release, sizeof(*ccu), GFP_KERNEL);
+	if (!ccu)
+		return -ENOMEM;
+
+	ret = sunxi_ccu_probe(ccu, dev, dev->of_node, reg, desc);
+	if (ret) {
+		devres_free(ccu);
+		return ret;
+	}
+
+	devres_add(dev, ccu);
+
+	return 0;
+}
+
+void of_sunxi_ccu_probe(struct device_node *node, void __iomem *reg,
+			const struct sunxi_ccu_desc *desc)
+{
+	struct sunxi_ccu *ccu;
+	int ret;
+
+	ccu = kzalloc(sizeof(*ccu), GFP_KERNEL);
+	if (!ccu)
+		return;
+
+	ret = sunxi_ccu_probe(ccu, NULL, node, reg, desc);
+	if (ret) {
+		pr_err("%pOF: probing clocks failed: %d\n", node, ret);
+		kfree(ccu);
+	}
+}