[PATCH v9 18/22] powerpc: Implement nvram ioctls

Finn Thain
2019-01-15T04:23:06Z

Add the powerpc-specific ioctls to the nvram module. This allows the nvram
module to replace the generic_nvram module.

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
On PPC32, the IOC_NVRAM_SYNC ioctl call always returns 0, even for those
platforms that don't implement ppc_md.nvram_sync. This patch retains
that quirk. It may be better to return an error (which is what PPC64 does).

Changed since v8:
- Changed #else to fully specified #elif conditional.
- Changed arch_nvram_ops method calls to ppc_md method calls.
---
drivers/char/nvram.c | 38 ++++++++++++++++++++++++++++++++++++++
include/linux/nvram.h | 2 ++
2 files changed, 40 insertions(+)

diff --git a/drivers/char/nvram.c b/drivers/char/nvram.c
index c9e295d73dc5..944f05fddacd 100644
--- a/drivers/char/nvram.c
+++ b/drivers/char/nvram.c
@@ -48,6 +48,9 @@
#include <linux/mutex.h>
#include <linux/pagemap.h>

+#ifdef CONFIG_PPC
+#include <asm/nvram.h>
+#endif

static DEFINE_MUTEX(nvram_mutex);
static DEFINE_SPINLOCK(nvram_state_lock);
@@ -283,6 +286,38 @@ static long nvram_misc_ioctl(struct file *file, unsigned int cmd,
long ret = -ENOTTY;

switch (cmd) {
+#ifdef CONFIG_PPC
+ case OBSOLETE_PMAC_NVRAM_GET_OFFSET:
+ pr_warn("nvram: Using obsolete PMAC_NVRAM_GET_OFFSET ioctl\n");
+ /* fall through */
+ case IOC_NVRAM_GET_OFFSET:
+ ret = -EINVAL;
+#ifdef CONFIG_PPC_PMAC
+ if (machine_is(powermac)) {
+ int part, offset;
+
+ if (copy_from_user(&part, (void __user *)arg,
+ sizeof(part)) != 0)
+ return -EFAULT;
+ if (part < pmac_nvram_OF || part > pmac_nvram_NR)
+ return -EINVAL;
+ offset = pmac_get_partition(part);
+ if (copy_to_user((void __user *)arg,
+ &offset, sizeof(offset)) != 0)
+ return -EFAULT;
+ ret = 0;
+ }
+#endif
+ break;
+ case IOC_NVRAM_SYNC:
+ if (ppc_md.nvram_sync != NULL) {
+ mutex_lock(&nvram_mutex);
+ ppc_md.nvram_sync();
+ mutex_unlock(&nvram_mutex);
+ }
+ ret = 0;
+ break;
+#elif defined(CONFIG_X86) || defined(CONFIG_M68K)
case NVRAM_INIT:
/* initialize NVRAM contents and checksum */
if (!capable(CAP_SYS_ADMIN))
@@ -306,6 +341,7 @@ static long nvram_misc_ioctl(struct file *file, unsigned int cmd,
mutex_unlock(&nvram_mutex);
}
break;
+#endif /* CONFIG_X86 || CONFIG_M68K */
}
return ret;
}
@@ -321,12 +357,14 @@ static int nvram_misc_open(struct inode *inode, struct file *file)
return -EBUSY;
}

+#if defined(CONFIG_X86) || defined(CONFIG_M68K)
/* Prevent multiple writers if the set_checksum ioctl is implemented. */
if ((arch_nvram_ops.set_checksum != NULL) &&
(file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE)) {
spin_unlock(&nvram_state_lock);
return -EBUSY;
}
+#endif

if (file->f_flags & O_EXCL)
nvram_open_mode |= NVRAM_EXCL;
diff --git a/include/linux/nvram.h b/include/linux/nvram.h
index 9df85703735c..9e3a957c8f1f 100644
--- a/include/linux/nvram.h
+++ b/include/linux/nvram.h
@@ -31,8 +31,10 @@ struct nvram_ops {
void (*write_byte)(unsigned char, int);
ssize_t (*read)(char *, size_t, loff_t *);
ssize_t (*write)(char *, size_t, loff_t *);
+#if defined(CONFIG_X86) || defined(CONFIG_M68K)
long (*initialize)(void);
long (*set_checksum)(void);
+#endif
};

extern const struct nvram_ops arch_nvram_ops;
--
2.19.2