[PATCH v9 05/22] m68k/atari: Implement arch_nvram_ops struct

Finn Thain
2019-01-15T04:24:26Z

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>
---
Changed since v8:
- Added static inline wrapper functions to nvram.h.
- Removed excess whitespace.
- Renamed functions to avoid collisions with nvram.h wrapper functions.
- Moved nvram_check_checksum() changes to the preceding patch.
---
arch/m68k/atari/nvram.c | 49 +++++++++++++++++++++++++++++++++++++++++
include/linux/nvram.h | 14 ++++++++++++
2 files changed, 63 insertions(+)

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;
diff --git a/include/linux/nvram.h b/include/linux/nvram.h
index eb5b52a9a747..a1e01dc89759 100644
--- a/include/linux/nvram.h
+++ b/include/linux/nvram.h
@@ -5,8 +5,18 @@
#include <linux/errno.h>
#include <uapi/linux/nvram.h>

+struct nvram_ops {
+ ssize_t (*get_size)(void);
+ ssize_t (*read)(char *, size_t, loff_t *);
+ ssize_t (*write)(char *, size_t, loff_t *);
+};
+
+extern const struct nvram_ops arch_nvram_ops;
+
static inline ssize_t nvram_get_size(void)
{
+ if (arch_nvram_ops.get_size)
+ return arch_nvram_ops.get_size();
return -ENODEV;
}

@@ -21,11 +31,15 @@ static inline void nvram_write_byte(unsigned char val, int addr)

static inline ssize_t nvram_read(char *buf, size_t count, loff_t *ppos)
{
+ if (arch_nvram_ops.read)
+ return arch_nvram_ops.read(buf, count, ppos);
return -ENODEV;
}

static inline ssize_t nvram_write(char *buf, size_t count, loff_t *ppos)
{
+ if (arch_nvram_ops.write)
+ return arch_nvram_ops.write(buf, count, ppos);
return -ENODEV;
}

--
2.19.2