On Sat, 29 Dec 2018, I wrote:
On Fri, 28 Dec 2018, LEROY Christophe wrote:
--- a/drivers/char/nvram.c
+++ b/drivers/char/nvram.c
@@ -21,13 +21,6 @@
* ioctl(NVRAM_SETCKS) (doesn't change contents, just makes checksum valid
* again; use with care!)
*
- * This file also provides some functions for other parts of the kernel that
- * want to access the NVRAM: nvram_{read,write,check_checksum,set_checksum}.
- * Obviously this can be used only if this driver is always configured into
- * the kernel and is not a module. Since the functions are used by
some Atari
- * drivers, this is the case on the Atari.
- *
- *
* 1.1 Cesar Barros: SMP locking fixes
* added changelog
* 1.2 Erik Gilling: Cobalt Networks support
@@ -39,64 +32,6 @@
#include <linux/module.h>
#include <linux/nvram.h>
-
-#define PC 1
-#define ATARI 2
-
-/* select machine configuration */
-#if defined(CONFIG_ATARI)
-# define MACH ATARI
-#elif defined(__i386__) || defined(__x86_64__) || defined(__arm__)
/* and ?? */
-# define MACH PC
-#else
-# error Cannot build nvram driver for this machine configuration.
-#endif
-
-#if MACH == PC
-
-/* RTC in a PC */
-#define CHECK_DRIVER_INIT() 1
-
-/* On PCs, the checksum is built only over bytes 2..31 */
-#define PC_CKS_RANGE_START 2
-#define PC_CKS_RANGE_END 31
-#define PC_CKS_LOC 32
-#define NVRAM_BYTES (128-NVRAM_FIRST_BYTE)
-
-#define mach_check_checksum pc_check_checksum
-#define mach_set_checksum pc_set_checksum
-#define mach_proc_infos pc_proc_infos
-
-#endif
-
-#if MACH == ATARI
-
-/* Special parameters for RTC in Atari machines */
-#include <asm/atarihw.h>
-#include <asm/atariints.h>
-#define RTC_PORT(x) (TT_RTC_BAS + 2*(x))
-#define CHECK_DRIVER_INIT() (MACH_IS_ATARI && ATARIHW_PRESENT(TT_CLK))
-
-#define NVRAM_BYTES 50
-
-/* On Ataris, the checksum is over all bytes except the checksum bytes
- * themselves; these are at the very end */
-#define ATARI_CKS_RANGE_START 0
-#define ATARI_CKS_RANGE_END 47
-#define ATARI_CKS_LOC 48
-
-#define mach_check_checksum atari_check_checksum
-#define mach_set_checksum atari_set_checksum
-#define mach_proc_infos atari_proc_infos
-
-#endif
-
-/* Note that *all* calls to CMOS_READ and CMOS_WRITE must be done with
- * rtc_lock held. Due to the index-port/data-port design of the RTC, we
- * don't want two different things trying to get to it at once. (e.g. the
- * periodic 11 min sync from kernel/time/ntp.c vs. this driver.)
- */
-
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/miscdevice.h>
@@ -120,12 +55,9 @@ static int nvram_open_mode; /* special open modes */
#define NVRAM_WRITE 1 /* opened for writing (exclusive) */
#define NVRAM_EXCL 2 /* opened with O_EXCL */
-static int mach_check_checksum(void);
-static void mach_set_checksum(void);
-
#ifdef CONFIG_PROC_FS
-static void mach_proc_infos(unsigned char *contents, struct seq_file *seq,
- void *offset);
+static void pc_nvram_proc_read(unsigned char *contents, struct
seq_file *seq,
+ void *offset);
#endif
/*
@@ -139,6 +71,14 @@ static void mach_proc_infos(unsigned char
*contents, struct seq_file *seq,
* know about the RTC cruft.
*/
+#define NVRAM_BYTES (128 - NVRAM_FIRST_BYTE)
+
+/* Note that *all* calls to CMOS_READ and CMOS_WRITE must be done with
+ * rtc_lock held. Due to the index-port/data-port design of the RTC, we
+ * don't want two different things trying to get to it at once. (e.g. the
+ * periodic 11 min sync from kernel/time/ntp.c vs. this driver.)
+ */
+
unsigned char __nvram_read_byte(int i)
{
return CMOS_READ(NVRAM_FIRST_BYTE + i);
@@ -174,9 +114,22 @@ void nvram_write_byte(unsigned char c, int i)
}
EXPORT_SYMBOL(nvram_write_byte);
+/* On PCs, the checksum is built only over bytes 2..31 */
+#define PC_CKS_RANGE_START 2
+#define PC_CKS_RANGE_END 31
+#define PC_CKS_LOC 32
+
int __nvram_check_checksum(void)
{
- return mach_check_checksum();
+ int i;
+ unsigned short sum = 0;
+ unsigned short expect;
+
+ for (i = PC_CKS_RANGE_START; i <= PC_CKS_RANGE_END; ++i)
+ sum += __nvram_read_byte(i);
+ expect = __nvram_read_byte(PC_CKS_LOC)<<8 |
+ __nvram_read_byte(PC_CKS_LOC+1);
+ return (sum & 0xffff) == expect;
}
I don't understand how this is part of the code move.
Does the pc specific checksum becomes the generic one ?
This is not generic code, of course. Please refer to the two patches
that follow this one, in which all of the x86-specific code gets wrapped
with #ifdef CONFIG_X86.
This code gets moved because the MACH macro is made redundant. You might
defer this code motion to patch 4 or patch 5 but I don't see that as being
an improvement.
[...]
You may argue that there should be no CONFIG_X86 code in drivers/char.
I think I now remember why this x86-specific code doesn't get moved from
drivers/char to arch/x86 in this patch series.
In the case of PPC32 and PPC64, the nvram accessors are presently built-in
using rules like this,
arch/powerpc/platforms/powermac/Makefile:obj-$(CONFIG_PPC64) += nvram.o
arch/powerpc/platforms/powernv/Makefile:obj-y += ... opal-nvram.o ...
arch/powerpc/platforms/pseries/Makefile:obj-y := ... nvram.o ...
... or like this,
arch/powerpc/platforms/powermac/Makefile:obj-$(CONFIG_NVRAM:m=y) += nvram.o
... except in one case they are in a separate module, though this doesn't
work for built-in callers such as chrp_init2(),
arch/powerpc/platforms/chrp/Makefile:obj-$(CONFIG_NVRAM) += nvram.o
Anyway, I didn't think that any of these options would make it past the
x86 maintainers so I just left the x86-specific code in place.
--
