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Groups > linux.kernel > #1182324
| From | Finn Thain <fthain@telegraphics.com.au> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | [RFC v4 08/25] char/nvram: Allow the set_checksum and initialize ioctls to be omitted |
| Date | 2015-07-12 12:50 +0200 |
| Message-ID | <pLmZB-7cl-39@gated-at.bofh.it> (permalink) |
| References | <pLmZz-7cl-3@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
The drivers/char/nvram module has previously only supported RTC "CMOS"
NVRAM, for which it provides appropriate checksum ioctls. Make these
ioctls optional so the module can be re-used with other kinds of NVRAM.
The ops struct methods that implement the ioctls now return error
codes so that a multi-platform kernel binary can do the right thing when
running on hardware without suitable NVRAM.
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
---
Changed since v1:
- Don't bother acquiring the mutex for unimplemented ioctls.
---
drivers/char/nvram.c | 71 ++++++++++++++++++++++++++++----------------------
include/linux/nvram.h | 2 +
2 files changed, 43 insertions(+), 30 deletions(-)
Index: linux/drivers/char/nvram.c
===================================================================
--- linux.orig/drivers/char/nvram.c 2015-07-12 20:25:00.000000000 +1000
+++ linux/drivers/char/nvram.c 2015-07-12 20:25:02.000000000 +1000
@@ -153,16 +153,25 @@ static void __nvram_set_checksum(void)
__nvram_write_byte(sum & 0xff, PC_CKS_LOC + 1);
}
-#if 0
-void nvram_set_checksum(void)
+static long nvram_set_checksum(void)
{
- unsigned long flags;
+ spin_lock_irq(&rtc_lock);
+ __nvram_set_checksum();
+ spin_unlock_irq(&rtc_lock);
+ return 0;
+}
+
+static long nvram_initialize(void)
+{
+ ssize_t i;
- spin_lock_irqsave(&rtc_lock, flags);
+ spin_lock_irq(&rtc_lock);
+ for (i = 0; i < NVRAM_BYTES; ++i)
+ __nvram_write_byte(0, i);
__nvram_set_checksum();
- spin_unlock_irqrestore(&rtc_lock, flags);
+ spin_unlock_irq(&rtc_lock);
+ return 0;
}
-#endif /* 0 */
static ssize_t nvram_get_size(void)
{
@@ -173,6 +182,8 @@ const struct nvram_ops arch_nvram_ops =
.read_byte = nvram_read_byte,
.write_byte = nvram_write_byte,
.get_size = nvram_get_size,
+ .set_checksum = nvram_set_checksum,
+ .initialize = nvram_initialize,
};
EXPORT_SYMBOL(arch_nvram_ops);
@@ -272,51 +283,51 @@ checksum_err:
static long nvram_misc_ioctl(struct file *file, unsigned int cmd,
unsigned long arg)
{
- int i;
+ long ret = -ENOTTY;
switch (cmd) {
-
case NVRAM_INIT:
/* initialize NVRAM contents and checksum */
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
- mutex_lock(&nvram_mutex);
- 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);
- mutex_unlock(&nvram_mutex);
- return 0;
-
+ if (arch_nvram_ops.initialize != NULL) {
+ mutex_lock(&nvram_mutex);
+ ret = arch_nvram_ops.initialize();
+ mutex_unlock(&nvram_mutex);
+ }
+ break;
case NVRAM_SETCKS:
/* just set checksum, contents unchanged (maybe useful after
* checksum garbaged somehow...) */
if (!capable(CAP_SYS_ADMIN))
return -EACCES;
- mutex_lock(&nvram_mutex);
- spin_lock_irq(&rtc_lock);
- __nvram_set_checksum();
- spin_unlock_irq(&rtc_lock);
- mutex_unlock(&nvram_mutex);
- return 0;
-
- default:
- return -ENOTTY;
+ if (arch_nvram_ops.set_checksum != NULL) {
+ mutex_lock(&nvram_mutex);
+ ret = arch_nvram_ops.set_checksum();
+ mutex_unlock(&nvram_mutex);
+ }
+ break;
}
+ return ret;
}
static int nvram_misc_open(struct inode *inode, struct file *file)
{
spin_lock(&nvram_state_lock);
+ /* Prevent multiple readers/writers if desired. */
if ((nvram_open_cnt && (file->f_flags & O_EXCL)) ||
- (nvram_open_mode & NVRAM_EXCL) ||
- ((file->f_mode & FMODE_WRITE) && (nvram_open_mode & NVRAM_WRITE))) {
+ (nvram_open_mode & NVRAM_EXCL)) {
+ spin_unlock(&nvram_state_lock);
+ return -EBUSY;
+ }
+
+ /* 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;
}
Index: linux/include/linux/nvram.h
===================================================================
--- linux.orig/include/linux/nvram.h 2015-07-12 20:25:00.000000000 +1000
+++ linux/include/linux/nvram.h 2015-07-12 20:25:02.000000000 +1000
@@ -17,6 +17,8 @@ struct nvram_ops {
unsigned char (*read_byte)(int);
void (*write_byte)(unsigned char, int);
ssize_t (*get_size)(void);
+ long (*set_checksum)(void);
+ long (*initialize)(void);
};
extern const struct nvram_ops arch_nvram_ops;
--
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[RFC v4 00/25] Re-use nvram module Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 11/25] m68k/atari: Implement arch_nvram_ops methods and enable CONFIG_HAVE_ARCH_NVRAM_OPS Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 16/25] powerpc: Implement nvram sync ioctl Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 15/25] powerpc: Implement arch_nvram_ops.get_size() and remove old nvram_* exports Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 24/25] m68k/mac: Fix PRAM accessors Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 18/25] nvram: Drop nvram_* symbol exports and prototypes Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 14/25] powerpc: Add missing ppc_md.nvram_size for CHRP and PowerMac Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 19/25] powerpc: Remove CONFIG_GENERIC_NVRAM and adopt CONFIG_HAVE_ARCH_NVRAM_OPS Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 09/25] char/nvram: Implement NVRAM read/write methods Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 13/25] powerpc: Cleanup nvram includes Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 10/25] char/nvram: Use generic fixed_size_llseek() Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 08/25] char/nvram: Allow the set_checksum and initialize ioctls to be omitted Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 01/25] scsi/atari_scsi: Dont select CONFIG_NVRAM Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 12/25] char/nvram: Add "devname:nvram" module alias Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 03/25] m68k/atari: Move Atari-specific code out of drivers/char/nvram.c Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
Re: [RFC v4 03/25] m68k/atari: Move Atari-specific code out of drivers/char/nvram.c Finn Thain <fthain@telegraphics.com.au> - 2015-07-14 10:20 +0200
Re: [RFC v4 03/25] m68k/atari: Move Atari-specific code out of drivers/char/nvram.c Geert Uytterhoeven <geert@linux-m68k.org> - 2015-07-14 10:30 +0200
Re: [RFC v4 03/25] m68k/atari: Move Atari-specific code out of drivers/char/nvram.c Andreas Schwab <schwab@linux-m68k.org> - 2015-07-14 10:40 +0200
[RFC v4 21/25] powerpc: Adopt nvram module for PPC64 Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 25/25] m68k: Dispatch nvram_ops calls to Atari or Mac functions Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 23/25] m68k/mac: Use macros for RTC accesses not magic numbers Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 22/25] m68k/mac: Adopt naming and calling conventions for PRAM routines Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
[RFC v4 04/25] m68k/atari: Replace nvram_{read,write}_byte with arch_nvram_ops Finn Thain <fthain@telegraphics.com.au> - 2015-07-12 12:50 +0200
Re: [RFC v4 00/25] Re-use nvram module Geert Uytterhoeven <geert@linux-m68k.org> - 2015-07-13 10:00 +0200
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