[PATCH v7 15/26] powerpc: Implement nvram sync ioctl

Finn Thain
2015-11-01T10:49:07Z

[-- Attachment #1: nvram-add-powerpc-ioctls --]
[-- Type: text/plain, Size: 5804 bytes --]

Add the powerpc-specific sync() method to struct nvram_ops and implement
the corresponding ioctl in the nvram module. This allows the nvram module
to replace the generic_nvram module.

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 might be better to return -EINVAL (which is what PPC64 does).

Changed since v1:
- Don't bother acquiring the mutex for unimplemented ioctls.

Changed since v5:
- The IOC_NVRAM_GET_OFFSET ioctl returns -EINVAL on PowerPC platforms
other than Power Mac, and -ENOTTY on architectures other than PowerPC.
This is more consistent with the old generic_nvram module.

---
arch/powerpc/include/asm/nvram.h | 3 ---
arch/powerpc/kernel/setup_32.c | 6 +++---
drivers/char/generic_nvram.c | 2 +-
drivers/char/nvram.c | 39 +++++++++++++++++++++++++++++++++++++++
include/linux/nvram.h | 4 ++++
5 files changed, 47 insertions(+), 7 deletions(-)

Index: linux/drivers/char/nvram.c
===================================================================
--- linux.orig/drivers/char/nvram.c 2015-11-01 21:41:37.000000000 +1100
+++ linux/drivers/char/nvram.c 2015-11-01 21:41:42.000000000 +1100
@@ -48,6 +48,11 @@
#include <linux/mutex.h>

+#ifdef CONFIG_PPC
+#include <asm/nvram.h>
+#include <asm/machdep.h>
+#endif
+
static DEFINE_MUTEX(nvram_mutex);
static DEFINE_SPINLOCK(nvram_state_lock);
static int nvram_open_cnt; /* #times opened */
@@ -338,6 +343,37 @@ static long nvram_misc_ioctl(struct file
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 (arch_nvram_ops.sync != NULL) {
+ mutex_lock(&nvram_mutex);
+ ret = arch_nvram_ops.sync();
+ mutex_unlock(&nvram_mutex);
+ }
+ break;
+#else /* !CONFIG_PPC */
case NVRAM_INIT:
/* initialize NVRAM contents and checksum */
if (!capable(CAP_SYS_ADMIN))
@@ -361,6 +397,7 @@ static long nvram_misc_ioctl(struct file
mutex_unlock(&nvram_mutex);
}
break;
+#endif /* CONFIG_PPC */
}
return ret;
}
@@ -376,6 +413,7 @@ static int nvram_misc_open(struct inode
return -EBUSY;
}

+#ifndef CONFIG_PPC
/* Prevent multiple writers if the set_checksum ioctl is implemented. */
if ((arch_nvram_ops.set_checksum != NULL) &&
(file->f_mode & FMODE_WRITE) &&
@@ -383,6 +421,7 @@ static int nvram_misc_open(struct inode
spin_unlock(&nvram_state_lock);
return -EBUSY;
}
+#endif

if (file->f_flags & O_EXCL)
nvram_open_mode |= NVRAM_EXCL;
Index: linux/include/linux/nvram.h
===================================================================
--- linux.orig/include/linux/nvram.h 2015-11-01 21:41:32.000000000 +1100
+++ linux/include/linux/nvram.h 2015-11-01 21:41:42.000000000 +1100
@@ -17,8 +17,12 @@ struct nvram_ops {
unsigned char (*read_byte)(int);
void (*write_byte)(unsigned char, int);
ssize_t (*get_size)(void);
+#ifdef CONFIG_PPC
+ long (*sync)(void);
+#else
long (*set_checksum)(void);
long (*initialize)(void);
+#endif
};

extern const struct nvram_ops arch_nvram_ops;
Index: linux/arch/powerpc/include/asm/nvram.h
===================================================================
--- linux.orig/arch/powerpc/include/asm/nvram.h 2015-11-01 21:41:41.000000000 +1100
+++ linux/arch/powerpc/include/asm/nvram.h 2015-11-01 21:41:42.000000000 +1100
@@ -78,9 +78,6 @@ extern int pmac_get_partition(int partit
extern u8 pmac_xpram_read(int xpaddr);
extern void pmac_xpram_write(int xpaddr, u8 data);

-/* Synchronize NVRAM */
-extern void nvram_sync(void);
-
/* Initialize NVRAM OS partition */
extern int __init nvram_init_os_partition(struct nvram_os_partition *part);

Index: linux/arch/powerpc/kernel/setup_32.c
===================================================================
--- linux.orig/arch/powerpc/kernel/setup_32.c 2015-11-01 21:41:41.000000000 +1100
+++ linux/arch/powerpc/kernel/setup_32.c 2015-11-01 21:41:42.000000000 +1100
@@ -176,7 +176,6 @@ __setup("l3cr=", ppc_setup_l3cr);

#ifdef CONFIG_GENERIC_NVRAM

-/* Generic nvram hooks used by drivers/char/gen_nvram.c */
unsigned char nvram_read_byte(int addr)
{
if (ppc_md.nvram_read_val)
@@ -199,15 +198,16 @@ static ssize_t ppc_nvram_get_size(void)
return -ENODEV;
}

-void nvram_sync(void)
+static long ppc_nvram_sync(void)
{
if (ppc_md.nvram_sync)
ppc_md.nvram_sync();
+ return 0;
}
-EXPORT_SYMBOL(nvram_sync);

const struct nvram_ops arch_nvram_ops = {
.get_size = ppc_nvram_get_size,
+ .sync = ppc_nvram_sync,
};
EXPORT_SYMBOL(arch_nvram_ops);

Index: linux/drivers/char/generic_nvram.c
===================================================================
--- linux.orig/drivers/char/generic_nvram.c 2015-11-01 21:41:41.000000000 +1100
+++ linux/drivers/char/generic_nvram.c 2015-11-01 21:41:42.000000000 +1100
@@ -111,7 +111,7 @@ static int nvram_ioctl(struct file *file
}
#endif /* CONFIG_PPC_PMAC */
case IOC_NVRAM_SYNC:
- nvram_sync();
+ arch_nvram_ops.sync();
break;
default:
return -EINVAL;