powerpc: Enable HAVE_ARCH_NVRAM_OPS and disable GENERIC_NVRAM

Switch PPC32 kernels from the generic_nvram module to the nvram module.

Also fix a theoretical bug where CHRP omits the chrp_nvram_init() call
when CONFIG_NVRAM_MODULE=m.
Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

arch/powerpc/Kconfig

@@ -178,6 +178,7 @@ config PPC
 	select HAVE_ARCH_KGDB
 	select HAVE_ARCH_MMAP_RND_BITS
 	select HAVE_ARCH_MMAP_RND_COMPAT_BITS	if COMPAT
+	select HAVE_ARCH_NVRAM_OPS		if PPC32
 	select HAVE_ARCH_SECCOMP_FILTER
 	select HAVE_ARCH_TRACEHOOK
 	select HAVE_CBPF_JIT			if !PPC64
@@ -274,11 +275,6 @@ config SYSVIPC_COMPAT
 	depends on COMPAT && SYSVIPC
 	default y
 
-# All PPC32s use generic nvram driver through ppc_md
-config GENERIC_NVRAM
-	bool
-	default y if PPC32
-
 config SCHED_OMIT_FRAME_POINTER
 	bool
 	default y

arch/powerpc/include/asm/nvram.h

@@ -78,9 +78,6 @@ extern int	pmac_get_partition(int partition);
 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);
 

arch/powerpc/kernel/setup_32.c

@@ -148,17 +148,6 @@ static int __init ppc_setup_l3cr(char *str)
 }
 __setup("l3cr=", ppc_setup_l3cr);
 
-#ifdef CONFIG_GENERIC_NVRAM
-
-void nvram_sync(void)
-{
-	if (ppc_md.nvram_sync)
-		ppc_md.nvram_sync();
-}
-EXPORT_SYMBOL(nvram_sync);
-
-#endif /* CONFIG_NVRAM */
-
 static int __init ppc_init(void)
 {
 	/* clear the progress line */

arch/powerpc/platforms/chrp/Makefile

 obj-y				+= setup.o time.o pegasos_eth.o pci.o
 obj-$(CONFIG_SMP)		+= smp.o
-obj-$(CONFIG_NVRAM)		+= nvram.o
+obj-$(CONFIG_NVRAM:m=y)		+= nvram.o

arch/powerpc/platforms/chrp/setup.c

@@ -550,7 +550,7 @@ static void __init chrp_init_IRQ(void)
 static void __init
 chrp_init2(void)
 {
-#ifdef CONFIG_NVRAM
+#if IS_ENABLED(CONFIG_NVRAM)
 	chrp_nvram_init();
 #endif
 

arch/powerpc/platforms/powermac/setup.c

@@ -316,8 +316,7 @@ static void __init pmac_setup_arch(void)
 	find_via_pmu();
 	smu_init();
 
-#if defined(CONFIG_NVRAM) || defined(CONFIG_NVRAM_MODULE) || \
-    defined(CONFIG_PPC64)
+#if IS_ENABLED(CONFIG_NVRAM) || defined(CONFIG_PPC64)
 	pmac_nvram_init();
 #endif
 #ifdef CONFIG_PPC32

drivers/char/Kconfig

@@ -244,25 +244,24 @@ source "drivers/char/hw_random/Kconfig"
 
 config NVRAM
 	tristate "/dev/nvram support"
-	depends on X86 || GENERIC_NVRAM || HAVE_ARCH_NVRAM_OPS
-	default M68K
+	depends on X86 || HAVE_ARCH_NVRAM_OPS
+	default M68K || PPC
 	---help---
 	  If you say Y here and create a character special file /dev/nvram
 	  with major number 10 and minor number 144 using mknod ("man mknod"),
-	  you get read and write access to the extra bytes of non-volatile
-	  memory in the real time clock (RTC), which is contained in every PC
-	  and most Ataris.  The actual number of bytes varies, depending on the
-	  nvram in the system, but is usually 114 (128-14 for the RTC).
-
-	  This memory is conventionally called "CMOS RAM" on PCs and "NVRAM"
-	  on Ataris. /dev/nvram may be used to view settings there, or to
-	  change them (with some utility). It could also be used to frequently
+	  you get read and write access to the non-volatile memory.
+
+	  /dev/nvram may be used to view settings in NVRAM or to change them
+	  (with some utility). It could also be used to frequently
 	  save a few bits of very important data that may not be lost over
 	  power-off and for which writing to disk is too insecure. Note
 	  however that most NVRAM space in a PC belongs to the BIOS and you
 	  should NEVER idly tamper with it. See Ralf Brown's interrupt list
 	  for a guide to the use of CMOS bytes by your BIOS.
 
+	  This memory is conventionally called "NVRAM" on PowerPC machines,
+	  "CMOS RAM" on PCs, "NVRAM" on Ataris and "PRAM" on Macintoshes.
+
 	  To compile this driver as a module, choose M here: the
 	  module will be called nvram.
 

include/linux/nvram.h

@@ -5,6 +5,10 @@
 #include <linux/errno.h>
 #include <uapi/linux/nvram.h>
 
+#ifdef CONFIG_PPC
+#include <asm/machdep.h>
+#endif
+
 /**
  * struct nvram_ops - NVRAM functionality made available to drivers
  * @read: validate checksum (if any) then load a range of bytes from NVRAM
@@ -42,6 +46,8 @@ extern const struct nvram_ops arch_nvram_ops;
 static inline ssize_t nvram_get_size(void)
 {
 #ifdef CONFIG_PPC
+	if (ppc_md.nvram_size)
+		return ppc_md.nvram_size();
 #else
 	if (arch_nvram_ops.get_size)
 		return arch_nvram_ops.get_size();
@@ -52,6 +58,8 @@ static inline ssize_t nvram_get_size(void)
 static inline unsigned char nvram_read_byte(int addr)
 {
 #ifdef CONFIG_PPC
+	if (ppc_md.nvram_read_val)
+		return ppc_md.nvram_read_val(addr);
 #else
 	if (arch_nvram_ops.read_byte)
 		return arch_nvram_ops.read_byte(addr);
@@ -62,6 +70,8 @@ static inline unsigned char nvram_read_byte(int addr)
 static inline void nvram_write_byte(unsigned char val, int addr)
 {
 #ifdef CONFIG_PPC
+	if (ppc_md.nvram_write_val)
+		ppc_md.nvram_write_val(addr, val);
 #else
 	if (arch_nvram_ops.write_byte)
 		arch_nvram_ops.write_byte(val, addr);
@@ -98,15 +108,25 @@ static inline ssize_t nvram_write_bytes(char *buf, size_t count, loff_t *ppos)
 
 static inline ssize_t nvram_read(char *buf, size_t count, loff_t *ppos)
 {
+#ifdef CONFIG_PPC
+	if (ppc_md.nvram_read)
+		return ppc_md.nvram_read(buf, count, ppos);
+#else
 	if (arch_nvram_ops.read)
 		return arch_nvram_ops.read(buf, count, ppos);
+#endif
 	return nvram_read_bytes(buf, count, ppos);
 }
 
 static inline ssize_t nvram_write(char *buf, size_t count, loff_t *ppos)
 {
+#ifdef CONFIG_PPC
+	if (ppc_md.nvram_write)
+		return ppc_md.nvram_write(buf, count, ppos);
+#else
 	if (arch_nvram_ops.write)
 		return arch_nvram_ops.write(buf, count, ppos);
+#endif
 	return nvram_write_bytes(buf, count, ppos);
 }