char/nvram: Adopt arch_nvram_ops

NVRAMs on different platforms and architectures have different attributes
and access methods. E.g. some platforms have byte-at-a-time accessor
functions while others have byte-range accessor functions. Some have
checksum functionality while others do not. By calling ops struct methods
via the common wrapper functions, the nvram module and other drivers can
make use of the available NVRAM functionality in a portable way.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 24 insertions, 6 deletions

diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
index c98775bfd896..2df391f78986 100644
--- a/drivers/char/nvram.c
+++ b/drivers/char/nvram.c
@@ -52,9 +52,11 @@ static DEFINE_MUTEX(nvram_mutex);
 static DEFINE_SPINLOCK(nvram_state_lock);
 static int nvram_open_cnt;	/* #times opened */
 static int nvram_open_mode;	/* special open modes */
+static ssize_t nvram_size;
 #define NVRAM_WRITE		1 /* opened for writing (exclusive) */
 #define NVRAM_EXCL		2 /* opened with O_EXCL */
 
+#ifdef CONFIG_X86
 /*
  * These functions are provided to be called internally or by other parts of
  * the kernel. It's up to the caller to ensure correct checksum before reading
@@ -145,6 +147,19 @@ void nvram_set_checksum(void)
 }
 #endif  /*  0  */
 
+static ssize_t pc_nvram_get_size(void)
+{
+	return NVRAM_BYTES;
+}
+
+const struct nvram_ops arch_nvram_ops = {
+	.read_byte      = pc_nvram_read_byte,
+	.write_byte     = pc_nvram_write_byte,
+	.get_size       = pc_nvram_get_size,
+};
+EXPORT_SYMBOL(arch_nvram_ops);
+#endif /* CONFIG_X86 */
+
 /*
  * The are the file operation function for user access to /dev/nvram
  */
@@ -152,7 +167,7 @@ void nvram_set_checksum(void)
 static loff_t nvram_misc_llseek(struct file *file, loff_t offset, int origin)
 {
 	return generic_file_llseek_size(file, offset, origin, MAX_LFS_FILESIZE,
-					NVRAM_BYTES);
+					nvram_size);
 }
 
 static ssize_t nvram_misc_read(struct file *file, char __user *buf,
@@ -303,8 +318,7 @@ static int nvram_misc_release(struct inode *inode, struct file *file)
 	return 0;
 }
 
-#ifdef CONFIG_PROC_FS
-
+#if defined(CONFIG_X86) && defined(CONFIG_PROC_FS)
 static const char * const floppy_types[] = {
 	"none", "5.25'' 360k", "5.25'' 1.2M", "3.5'' 720k", "3.5'' 1.44M",
 	"3.5'' 2.88M", "3.5'' 2.88M"
@@ -394,7 +408,7 @@ static int nvram_proc_read(struct seq_file *seq, void *offset)
 
 	return 0;
 }
-#endif /* CONFIG_PROC_FS */
+#endif /* CONFIG_X86 && CONFIG_PROC_FS */
 
 static const struct file_operations nvram_misc_fops = {
 	.owner		= THIS_MODULE,
@@ -416,13 +430,17 @@ static int __init nvram_module_init(void)
 {
 	int ret;
 
+	nvram_size = nvram_get_size();
+	if (nvram_size < 0)
+		return nvram_size;
+
 	ret = misc_register(&nvram_misc);
 	if (ret) {
 		pr_err("nvram: can't misc_register on minor=%d\n", NVRAM_MINOR);
 		return ret;
 	}
 
-#ifdef CONFIG_PROC_FS
+#if defined(CONFIG_X86) && defined(CONFIG_PROC_FS)
 	if (!proc_create_single("driver/nvram", 0, NULL, nvram_proc_read)) {
 		pr_err("nvram: can't create /proc/driver/nvram\n");
 		misc_deregister(&nvram_misc);
@@ -436,7 +454,7 @@ static int __init nvram_module_init(void)
 
 static void __exit nvram_module_exit(void)
 {
-#ifdef CONFIG_PROC_FS
+#if defined(CONFIG_X86) && defined(CONFIG_PROC_FS)
 	remove_proc_entry("driver/nvram", NULL);
 #endif
 	misc_deregister(&nvram_misc);