By implementing an arch_nvram_ops struct, any platform can re-use the
drivers/char/nvram.c module without needing any arch-specific code
in that module. Atari does so here.
Atari has one user of nvram_check_checksum() whereas the other "CMOS"
platforms don't use that function at all. Replace this
validate-checksum-and-read-byte sequence with the equivalent
rtc_nvram_ops.read() call and remove the now unused functions.
Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
Tested-by: Christian T. Steigies <cts@xxxxxxxxxx>
Acked-by: Geert Uytterhoeven <geert@xxxxxxxxxxxxxx>
---
The advantage of the new ops struct over the old global nvram_* functions
is that the misc device module can be shared by different platforms
without requiring every platform to implement every nvram_* function.
E.g. only RTC "CMOS" NVRAMs have a checksum for the entire NVRAM
and only PowerPC platforms have a "sync" ioctl.
---
arch/m68k/atari/nvram.c | 89 ++++++++++++++++++++++++---------------
drivers/scsi/atari_scsi.c | 8 ++--
include/linux/nvram.h | 9 ++++
3 files changed, 70 insertions(+), 36 deletions(-)
diff --git a/arch/m68k/atari/nvram.c b/arch/m68k/atari/nvram.c
index 3e620ee955ba..bafc9dc32830 100644
--- a/arch/m68k/atari/nvram.c
+++ b/arch/m68k/atari/nvram.c
@@ -39,33 +39,12 @@ unsigned char __nvram_read_byte(int i)
return CMOS_READ(NVRAM_FIRST_BYTE + i);
}
-unsigned char nvram_read_byte(int i)
-{
- unsigned long flags;
- unsigned char c;
-
- spin_lock_irqsave(&rtc_lock, flags);
- c = __nvram_read_byte(i);
- spin_unlock_irqrestore(&rtc_lock, flags);
- return c;
-}
-EXPORT_SYMBOL(nvram_read_byte);
-
/* This races nicely with trying to read with checksum checking */
void __nvram_write_byte(unsigned char c, int i)
{
CMOS_WRITE(c, NVRAM_FIRST_BYTE + i);
}
-void nvram_write_byte(unsigned char c, int i)
-{
- unsigned long flags;
-
- spin_lock_irqsave(&rtc_lock, flags);
- __nvram_write_byte(c, i);
- spin_unlock_irqrestore(&rtc_lock, flags);
-}
-
/* On Ataris, the checksum is over all bytes except the checksum bytes
* themselves; these are at the very end.
*/
@@ -84,18 +63,6 @@ int __nvram_check_checksum(void)
(__nvram_read_byte(ATARI_CKS_LOC + 1) == (sum & 0xff));
}
-int nvram_check_checksum(void)
-{
- unsigned long flags;
- int rv;
-
- spin_lock_irqsave(&rtc_lock, flags);
- rv = __nvram_check_checksum();
- spin_unlock_irqrestore(&rtc_lock, flags);
- return rv;
-}
-EXPORT_SYMBOL(nvram_check_checksum);
-
static void __nvram_set_checksum(void)
{
int i;
@@ -107,6 +74,62 @@ static void __nvram_set_checksum(void)
__nvram_write_byte(sum, ATARI_CKS_LOC + 1);
}
+static ssize_t 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 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 nvram_get_size(void)
+{
+ return NVRAM_BYTES;
+}
+
+const struct nvram_ops arch_nvram_ops = {
+ .read = nvram_read,
+ .write = nvram_write,
+ .get_size = nvram_get_size,
+};
+EXPORT_SYMBOL(arch_nvram_ops);
+
#ifdef CONFIG_PROC_FS
static struct {
unsigned char val;
diff --git a/drivers/scsi/atari_scsi.c b/drivers/scsi/atari_scsi.c
index 99e5729d910d..f55d13e400da 100644
--- a/drivers/scsi/atari_scsi.c
+++ b/drivers/scsi/atari_scsi.c
@@ -760,13 +760,15 @@ static int __init atari_scsi_probe(struct platform_device *pdev)
#ifdef CONFIG_NVRAM
else
/* Test if a host id is set in the NVRam */
- if (ATARIHW_PRESENT(TT_CLK) && nvram_check_checksum()) {
- unsigned char b = nvram_read_byte(16);
+ if (ATARIHW_PRESENT(TT_CLK)) {
+ unsigned char b;
+ loff_t offset = 16;
+ ssize_t count = arch_nvram_ops.read(&b, 1, &offset);
/* Arbitration enabled? (for TOS)
* If yes, use configured host ID
*/
- if (b & 0x80)
+ if ((count == 1) && (b & 0x80))
atari_scsi_template.this_id = b & 7;
}
#endif
diff --git a/include/linux/nvram.h b/include/linux/nvram.h
index 28bfb9ab94ca..4f78147e74d9 100644
--- a/include/linux/nvram.h
+++ b/include/linux/nvram.h
@@ -11,4 +11,13 @@ extern void __nvram_write_byte(unsigned char c, int i);
extern void nvram_write_byte(unsigned char c, int i);
extern int __nvram_check_checksum(void);
extern int nvram_check_checksum(void);
+
+struct nvram_ops {
+ ssize_t (*read)(char *, size_t, loff_t *);
+ ssize_t (*write)(char *, size_t, loff_t *);
+ ssize_t (*get_size)(void);
+};
+
+extern const struct nvram_ops arch_nvram_ops;
+
#endif /* _LINUX_NVRAM_H */
--
2.19.2
