[PATCH v8 09/25] m68k/atari: Implement arch_nvram_ops methods and enable CONFIG_HAVE_ARCH_NVRAM_OPS

[Finn Thain]

Atari RTC NVRAM has a checksum so implement the remaining arch_nvram_ops
methods for the set_checksum and initialize ioctls. Enable
CONFIG_HAVE_ARCH_NVRAM_OPS.

Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
Changed since v7:
 - Changed the default for CONFIG_NVRAM, because "select NVRAM" was
removed from ATARI_SCSI in patch 1.
---
 arch/m68k/Kconfig         |  3 +++
 arch/m68k/Kconfig.machine |  1 +
 arch/m68k/atari/nvram.c   | 24 ++++++++++++++++++++++++
 drivers/char/Kconfig      |  3 ++-
 4 files changed, 30 insertions(+), 1 deletion(-)

diff --git a/arch/m68k/Kconfig b/arch/m68k/Kconfig
index 1bc9f1ba759a..79e545f2520a 100644
--- a/arch/m68k/Kconfig
+++ b/arch/m68k/Kconfig
@@ -70,6 +70,9 @@ config ZONE_DMA
 	bool
 	default y
 
+config HAVE_ARCH_NVRAM_OPS
+	bool
+
 config HZ
 	int
 	default 1000 if CLEOPATRA
diff --git a/arch/m68k/Kconfig.machine b/arch/m68k/Kconfig.machine
index 64a641467736..0c8c4c7982c1 100644
--- a/arch/m68k/Kconfig.machine
+++ b/arch/m68k/Kconfig.machine
@@ -16,6 +16,7 @@ config ATARI
 	bool "Atari support"
 	depends on MMU
 	select MMU_MOTOROLA if MMU
+	select HAVE_ARCH_NVRAM_OPS
 	help
 	  This option enables support for the 68000-based Atari series of
 	  computers (including the TT, Falcon and Medusa). If you plan to use
diff --git a/arch/m68k/atari/nvram.c b/arch/m68k/atari/nvram.c
index bafc9dc32830..4b27f1683a37 100644
--- a/arch/m68k/atari/nvram.c
+++ b/arch/m68k/atari/nvram.c
@@ -74,6 +74,26 @@ static void __nvram_set_checksum(void)
 	__nvram_write_byte(sum, ATARI_CKS_LOC + 1);
 }
 
+static long nvram_set_checksum(void)
+{
+	spin_lock_irq(&rtc_lock);
+	__nvram_set_checksum();
+	spin_unlock_irq(&rtc_lock);
+	return 0;
+}
+
+static long nvram_initialize(void)
+{
+	loff_t i;
+
+	spin_lock_irq(&rtc_lock);
+	for (i = 0; i < NVRAM_BYTES; ++i)
+		__nvram_write_byte(0, i);
+	__nvram_set_checksum();
+	spin_unlock_irq(&rtc_lock);
+	return 0;
+}
+
 static ssize_t nvram_read(char *buf, size_t count, loff_t *ppos)
 {
 	char *p = buf;
@@ -120,6 +140,8 @@ static ssize_t nvram_write(char *buf, size_t count, loff_t *ppos)
 
 static ssize_t nvram_get_size(void)
 {
+	if (!MACH_IS_ATARI)
+		return -ENODEV;
 	return NVRAM_BYTES;
 }
 
@@ -127,6 +149,8 @@ const struct nvram_ops arch_nvram_ops = {
 	.read           = nvram_read,
 	.write          = nvram_write,
 	.get_size       = nvram_get_size,
+	.set_checksum   = nvram_set_checksum,
+	.initialize     = nvram_initialize,
 };
 EXPORT_SYMBOL(arch_nvram_ops);
 
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index 5b54595dfe30..f9960bd65481 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -236,7 +236,8 @@ source "drivers/char/hw_random/Kconfig"
 
 config NVRAM
 	tristate "/dev/nvram support"
-	depends on X86 || GENERIC_NVRAM
+	depends on X86 || GENERIC_NVRAM || HAVE_ARCH_NVRAM_OPS
+	default M68K
 	---help---
 	  If you say Y here and create a character special file /dev/nvram
 	  with major number 10 and minor number 144 using mknod ("man mknod"),
-- 
2.19.2