m68k/atari: Implement arch_nvram_ops struct

By implementing an arch_nvram_ops struct, a platform can re-use the
drivers/char/nvram.c module without needing any arch-specific code
in that module. Atari does so here.

Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 49 insertions, 0 deletions

diff --git a/arch/m68k/atari/nvram.c b/arch/m68k/atari/nvram.c
index 1d767847ffa6..e75adebe6e7d 100644
--- a/arch/m68k/atari/nvram.c
+++ b/arch/m68k/atari/nvram.c
@@ -74,6 +74,55 @@ static void __nvram_set_checksum(void)
         __nvram_write_byte(sum, ATARI_CKS_LOC + 1);
 }
 
+static ssize_t atari_nvram_read(char *buf, size_t count, loff_t *ppos)
+{
+        char *p = buf;
+        loff_t i;
+
+        spin_lock_irq(&rtc_lock);
+        if (!__nvram_check_checksum()) {
+                spin_unlock_irq(&rtc_lock);
+                return -EIO;
+        }
+        for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p)
+                *p = __nvram_read_byte(i);
+        spin_unlock_irq(&rtc_lock);
+
+        *ppos = i;
+        return p - buf;
+}
+
+static ssize_t atari_nvram_write(char *buf, size_t count, loff_t *ppos)
+{
+        char *p = buf;
+        loff_t i;
+
+        spin_lock_irq(&rtc_lock);
+        if (!__nvram_check_checksum()) {
+                spin_unlock_irq(&rtc_lock);
+                return -EIO;
+        }
+        for (i = *ppos; count > 0 && i < NVRAM_BYTES; --count, ++i, ++p)
+                __nvram_write_byte(*p, i);
+        __nvram_set_checksum();
+        spin_unlock_irq(&rtc_lock);
+
+        *ppos = i;
+        return p - buf;
+}
+
+static ssize_t atari_nvram_get_size(void)
+{
+        return NVRAM_BYTES;
+}
+
+const struct nvram_ops arch_nvram_ops = {
+        .read           = atari_nvram_read,
+        .write          = atari_nvram_write,
+        .get_size       = atari_nvram_get_size,
+};
+EXPORT_SYMBOL(arch_nvram_ops);
+
 #ifdef CONFIG_PROC_FS
 static struct {
         unsigned char val;