crypto: ixp4xx - convert to platform driver

The ixp4xx_crypto driver traditionally registers a bare platform
device without attaching it to a driver, and detects the hardware
at module init time by reading an SoC specific hardware register.

Change this to the conventional method of registering the platform
device from the platform code itself when the device is present,
turning the module_init/module_exit functions into probe/release
driver callbacks.

This enables compile-testing as well as potentially having ixp4xx
coexist with other ARMv5 platforms in the same kernel in the future.

Cc: Corentin Labbe <clabbe@baylibre.com>
Tested-by: Corentin Labbe <clabbe@baylibre.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

arch/arm/mach-ixp4xx/common.c

@@ -233,12 +233,38 @@ static struct platform_device *ixp46x_devices[] __initdata = {
 unsigned long ixp4xx_exp_bus_size;
 EXPORT_SYMBOL(ixp4xx_exp_bus_size);
 
+static struct platform_device_info ixp_dev_info __initdata = {
+	.name		= "ixp4xx_crypto",
+	.id		= 0,
+	.dma_mask	= DMA_BIT_MASK(32),
+};
+
+static int __init ixp_crypto_register(void)
+{
+	struct platform_device *pdev;
+
+	if (!(~(*IXP4XX_EXP_CFG2) & (IXP4XX_FEATURE_HASH |
+				IXP4XX_FEATURE_AES | IXP4XX_FEATURE_DES))) {
+		printk(KERN_ERR "ixp_crypto: No HW crypto available\n");
+		return -ENODEV;
+	}
+
+	pdev = platform_device_register_full(&ixp_dev_info);
+	if (IS_ERR(pdev))
+		return PTR_ERR(pdev);
+
+	return 0;
+}
+
 void __init ixp4xx_sys_init(void)
 {
 	ixp4xx_exp_bus_size = SZ_16M;
 
 	platform_add_devices(ixp4xx_devices, ARRAY_SIZE(ixp4xx_devices));
 
+	if (IS_ENABLED(CONFIG_CRYPTO_DEV_IXP4XX))
+		ixp_crypto_register();
+
 	if (cpu_is_ixp46x()) {
 		int region;
 

drivers/crypto/ixp4xx_crypto.c

@@ -229,8 +229,6 @@ static dma_addr_t crypt_phys;
 
 static int support_aes = 1;
 
-#define DRIVER_NAME "ixp4xx_crypto"
-
 static struct platform_device *pdev;
 
 static inline dma_addr_t crypt_virt2phys(struct crypt_ctl *virt)
@@ -453,11 +451,6 @@ static int init_ixp_crypto(struct device *dev)
 	int ret = -ENODEV;
 	u32 msg[2] = { 0, 0 };
 
-	if (! ( ~(*IXP4XX_EXP_CFG2) & (IXP4XX_FEATURE_HASH |
-				IXP4XX_FEATURE_AES | IXP4XX_FEATURE_DES))) {
-		dev_err(dev, "ixp_crypto: No HW crypto available\n");
-		return ret;
-	}
 	npe_c = npe_request(NPE_ID);
 	if (!npe_c)
 		return ret;
@@ -1441,26 +1434,17 @@ static struct ixp_aead_alg ixp4xx_aeads[] = {
 
 #define IXP_POSTFIX "-ixp4xx"
 
-static const struct platform_device_info ixp_dev_info __initdata = {
-	.name		= DRIVER_NAME,
-	.id		= 0,
-	.dma_mask	= DMA_BIT_MASK(32),
-};
-
-static int __init ixp_module_init(void)
+static int ixp_crypto_probe(struct platform_device *_pdev)
 {
 	int num = ARRAY_SIZE(ixp4xx_algos);
 	int i, err;
 
-	pdev = platform_device_register_full(&ixp_dev_info);
-	if (IS_ERR(pdev))
-		return PTR_ERR(pdev);
+	pdev = _pdev;
 
 	err = init_ixp_crypto(&pdev->dev);
-	if (err) {
-		platform_device_unregister(pdev);
+	if (err)
 		return err;
-	}
+
 	for (i = 0; i < num; i++) {
 		struct skcipher_alg *cra = &ixp4xx_algos[i].crypto;
 
@@ -1531,7 +1515,7 @@ static int __init ixp_module_init(void)
 	return 0;
 }
 
-static void __exit ixp_module_exit(void)
+static int ixp_crypto_remove(struct platform_device *pdev)
 {
 	int num = ARRAY_SIZE(ixp4xx_algos);
 	int i;
@@ -1546,11 +1530,16 @@ static void __exit ixp_module_exit(void)
 			crypto_unregister_skcipher(&ixp4xx_algos[i].crypto);
 	}
 	release_ixp_crypto(&pdev->dev);
-	platform_device_unregister(pdev);
+
+	return 0;
 }
 
-module_init(ixp_module_init);
-module_exit(ixp_module_exit);
+static struct platform_driver ixp_crypto_driver = {
+	.probe = ixp_crypto_probe,
+	.remove = ixp_crypto_remove,
+	.driver = { .name = "ixp4xx_crypto" },
+};
+module_platform_driver(ixp_crypto_driver);
 
 MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Christian Hohnstaedt <chohnstaedt@innominate.com>");