ramoops: use module parameters instead of platform data if not available

Use generic module parameters instead of platform data, if platform data
are not available.  This limitation has been introduced with commit
c3b92ce9e75 ("ramoops: use the platform data structure instead of module
params").

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Marco Stornelli <marco.stornelli@gmail.com>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Américo Wang <xiyou.wangcong@gmail.com>
Reported-by: Stevie Trujillo <stevie.trujillo@gmail.com>
Cc: Joe Perches <joe@perches.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/ramoops.c b/drivers/char/ramoops.c
index 1a9f5f6..32aa233 100644
--- a/drivers/char/ramoops.c
+++ b/drivers/char/ramoops.c
@@ -26,6 +26,7 @@
 #include <linux/io.h>
 #include <linux/ioport.h>
 #include <linux/platform_device.h>
+#include <linux/slab.h>
 #include <linux/ramoops.h>
 
 #define RAMOOPS_KERNMSG_HDR "===="
@@ -56,6 +57,9 @@
 	int max_count;
 } oops_cxt;
 
+static struct platform_device *dummy;
+static struct ramoops_platform_data *dummy_data;
+
 static void ramoops_do_dump(struct kmsg_dumper *dumper,
 		enum kmsg_dump_reason reason, const char *s1, unsigned long l1,
 		const char *s2, unsigned long l2)
@@ -106,27 +110,22 @@
 	struct ramoops_context *cxt = &oops_cxt;
 	int err = -EINVAL;
 
-	if (pdata) {
-		mem_size = pdata->mem_size;
-		mem_address = pdata->mem_address;
-	}
-
-	if (!mem_size) {
+	if (!pdata->mem_size) {
 		printk(KERN_ERR "ramoops: invalid size specification");
 		goto fail3;
 	}
 
-	rounddown_pow_of_two(mem_size);
+	rounddown_pow_of_two(pdata->mem_size);
 
-	if (mem_size < RECORD_SIZE) {
+	if (pdata->mem_size < RECORD_SIZE) {
 		printk(KERN_ERR "ramoops: size too small");
 		goto fail3;
 	}
 
-	cxt->max_count = mem_size / RECORD_SIZE;
+	cxt->max_count = pdata->mem_size / RECORD_SIZE;
 	cxt->count = 0;
-	cxt->size = mem_size;
-	cxt->phys_addr = mem_address;
+	cxt->size = pdata->mem_size;
+	cxt->phys_addr = pdata->mem_address;
 
 	if (!request_mem_region(cxt->phys_addr, cxt->size, "ramoops")) {
 		printk(KERN_ERR "ramoops: request mem region failed");
@@ -179,12 +178,36 @@
 
 static int __init ramoops_init(void)
 {
-	return platform_driver_probe(&ramoops_driver, ramoops_probe);
+	int ret;
+	ret = platform_driver_probe(&ramoops_driver, ramoops_probe);
+	if (ret == -ENODEV) {
+		/*
+		 * If we didn't find a platform device, we use module parameters
+		 * building platform data on the fly.
+		 */
+		dummy_data = kzalloc(sizeof(struct ramoops_platform_data),
+				     GFP_KERNEL);
+		if (!dummy_data)
+			return -ENOMEM;
+		dummy_data->mem_size = mem_size;
+		dummy_data->mem_address = mem_address;
+		dummy = platform_create_bundle(&ramoops_driver, ramoops_probe,
+			NULL, 0, dummy_data,
+			sizeof(struct ramoops_platform_data));
+
+		if (IS_ERR(dummy))
+			ret = PTR_ERR(dummy);
+		else
+			ret = 0;
+	}
+
+	return ret;
 }
 
 static void __exit ramoops_exit(void)
 {
 	platform_driver_unregister(&ramoops_driver);
+	kfree(dummy_data);
 }
 
 module_init(ramoops_init);