[PATCH v8 22/25] powerpc: Remove CONFIG_GENERIC_NVRAM and adopt CONFIG_HAVE_ARCH_NVRAM_OPS

From: Finn Thain
Date: Tue Dec 25 2018 - 19:45:15 EST


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.

Signed-off-by: Finn Thain <fthain@xxxxxxxxxxxxxxxxxxx>
Tested-by: Laurent Vivier <lvivier@xxxxxxxxxx>
Tested-by: Stan Johnson <userm57@xxxxxxxxx>
---
The change in the name of the module is visible to userspace. The module
that implements /dev/nvram on PowerPC now has suitable aliases, i.e.
MODULE_ALIAS_MISCDEV(NVRAM_MINOR);
MODULE_ALIAS("devname:nvram");
so that the device special file can be automatically created and the
module automatically loaded when needed. Previously this was not the case.

Changed since v7:
- Improved Kconfig help text for CONFIG_NVRAM.
- Changed the default for CONFIG_NVRAM, which used to be "n". This is to
reduce the risk that CONFIG_GENERIC_NVRAM=y accidentally gets changed to
CONFIG_NVRAM=n.
---
arch/powerpc/Kconfig | 2 +-
arch/powerpc/kernel/setup_32.c | 2 +-
arch/powerpc/platforms/chrp/Makefile | 2 +-
arch/powerpc/platforms/chrp/setup.c | 2 +-
arch/powerpc/platforms/powermac/setup.c | 3 +--
drivers/char/Kconfig | 19 +++++++++----------
6 files changed, 14 insertions(+), 16 deletions(-)

diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig
index 8be31261aec8..5b859b7f6599 100644
--- a/arch/powerpc/Kconfig
+++ b/arch/powerpc/Kconfig
@@ -272,7 +272,7 @@ config SYSVIPC_COMPAT
default y

# All PPC32s use generic nvram driver through ppc_md
-config GENERIC_NVRAM
+config HAVE_ARCH_NVRAM_OPS
bool
default y if PPC32

diff --git a/arch/powerpc/kernel/setup_32.c b/arch/powerpc/kernel/setup_32.c
index bdbe6acbef11..96782abb0c41 100644
--- a/arch/powerpc/kernel/setup_32.c
+++ b/arch/powerpc/kernel/setup_32.c
@@ -150,7 +150,7 @@ static int __init ppc_setup_l3cr(char *str)
}
__setup("l3cr=", ppc_setup_l3cr);

-#ifdef CONFIG_GENERIC_NVRAM
+#if IS_ENABLED(CONFIG_NVRAM)

static unsigned char ppc_nvram_read_byte(int addr)
{
diff --git a/arch/powerpc/platforms/chrp/Makefile b/arch/powerpc/platforms/chrp/Makefile
index 4b3bfadc70fa..dc3465cc8bc6 100644
--- a/arch/powerpc/platforms/chrp/Makefile
+++ b/arch/powerpc/platforms/chrp/Makefile
@@ -1,3 +1,3 @@
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
diff --git a/arch/powerpc/platforms/chrp/setup.c b/arch/powerpc/platforms/chrp/setup.c
index d6d8ffc0271e..ba216aef964a 100644
--- a/arch/powerpc/platforms/chrp/setup.c
+++ b/arch/powerpc/platforms/chrp/setup.c
@@ -556,7 +556,7 @@ 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

diff --git a/arch/powerpc/platforms/powermac/setup.c b/arch/powerpc/platforms/powermac/setup.c
index 2f00e3daafb0..ce340ae4ee38 100644
--- a/arch/powerpc/platforms/powermac/setup.c
+++ b/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
diff --git a/drivers/char/Kconfig b/drivers/char/Kconfig
index f9960bd65481..2a193b298d27 100644
--- a/drivers/char/Kconfig
+++ b/drivers/char/Kconfig
@@ -236,25 +236,24 @@ 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.

--
2.19.2