hwrng: geode - Revert managed API changes

After commit e9afc746299d ("hwrng: geode - Use linux/io.h instead of
asm/io.h") the geode-rng driver uses devres with pci_dev->dev to keep
track of resources, but does not actually register a PCI driver. This
results in the following issues:

1. The driver leaks memory because the driver does not attach to a
device. The driver only uses the PCI device as a reference. devm_*()
functions will release resources on driver detach, which the geode-rng
driver will never do. As a result,

2. The driver cannot be reloaded because there is always a use of the
ioport and region after the first load of the driver.

Revert the changes made by e9afc746299d ("hwrng: geode - Use linux/io.h
instead of asm/io.h").

Cc: <[e-mail]>
Signed-off-by: Prarit Bhargava <[e-mail]>
Fixes: 6e9b5e76882c ("hwrng: geode - Migrate to managed API")
Cc: Matt Mackall <[e-mail]>
Cc: Corentin LABBE <[e-mail]>
Cc: PrasannaKumar Muralidharan <[e-mail]>
Cc: Wei Yongjun <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Signed-off-by: Herbert Xu <[e-mail]>

drivers/char/hw_random/geode-rng.c

···
 #include <linux/module.h>
 #include <linux/pci.h>
 
+
+#define PFX	KBUILD_MODNAME ": "
+
 #define GEODE_RNG_DATA_REG   0x50
 #define GEODE_RNG_STATUS_REG 0x54
 
···
 
 static int __init mod_init(void)
 {
+	int err = -ENODEV;
 	struct pci_dev *pdev = NULL;
 	const struct pci_device_id *ent;
 	void __iomem *mem;
···
 
 	for_each_pci_dev(pdev) {
 		ent = pci_match_id(pci_tbl, pdev);
-		if (ent) {
-			rng_base = pci_resource_start(pdev, 0);
-			if (rng_base == 0)
-				return -ENODEV;
-
-			mem = devm_ioremap(&pdev->dev, rng_base, 0x58);
-			if (!mem)
-				return -ENOMEM;
-			geode_rng.priv = (unsigned long)mem;
-
-			pr_info("AMD Geode RNG detected\n");
-			return devm_hwrng_register(&pdev->dev, &geode_rng);
-		}
+		if (ent)
+			goto found;
 	}
-
 	/* Device not found. */
-	return -ENODEV;
+	goto out;
+
+found:
+	rng_base = pci_resource_start(pdev, 0);
+	if (rng_base == 0)
+		goto out;
+	err = -ENOMEM;
+	mem = ioremap(rng_base, 0x58);
+	if (!mem)
+		goto out;
+	geode_rng.priv = (unsigned long)mem;
+
+	pr_info("AMD Geode RNG detected\n");
+	err = hwrng_register(&geode_rng);
+	if (err) {
+		pr_err(PFX "RNG registering failed (%d)\n",
+		       err);
+		goto err_unmap;
+	}
+out:
+	return err;
+
+err_unmap:
+	iounmap(mem);
+	goto out;
 }
 
 static void __exit mod_exit(void)
 {
+	void __iomem *mem = (void __iomem *)geode_rng.priv;
+
+	hwrng_unregister(&geode_rng);
+	iounmap(mem);
 }
 
 module_init(mod_init);