MIPS: BCM47xx: Move NVRAM driver to the drivers/firmware/

After Broadcom switched from MIPS to ARM for their home routers we need
to have NVRAM driver in some common place (not arch/mips/). As explained
in Kconfig, this driver is responsible for parsing SoC configuration
data that is passed to the kernel in flash from the bootloader firmware
called "CFE".

We were thinking about putting it in bus directory, however there are
two possible buses for MIPS: drivers/ssb/ and drivers/bcma/. So this
won't fit there and this is why I would like to move this driver to the
drivers/firmware/.
Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Reviewed-by: Paul Walmsley <paul@pwsan.com>
Cc: linux-mips@linux-mips.org
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: Seiji Aguchi <seiji.aguchi@hds.com>
Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Mike Waychison <mikew@google.com>
Cc: Roy Franz <roy.franz@linaro.org>
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Patchwork: https://patchwork.linux-mips.org/patch/10544/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

MAINTAINERS

@@ -2265,6 +2265,12 @@ S:	Supported
 F:	drivers/gpio/gpio-bcm-kona.c
 F:	Documentation/devicetree/bindings/gpio/gpio-bcm-kona.txt
 
+BROADCOM NVRAM DRIVER
+M:	Rafał Miłecki <zajec5@gmail.com>
+L:	linux-mips@linux-mips.org
+S:	Maintained
+F:	drivers/firmware/broadcom/*
+
 BROADCOM SPECIFIC AMBA DRIVER (BCMA)
 M:	Rafał Miłecki <zajec5@gmail.com>
 L:	linux-wireless@vger.kernel.org

arch/mips/Kconfig

@@ -190,6 +190,7 @@ config BCM47XX
 	select USE_GENERIC_EARLY_PRINTK_8250
 	select GPIOLIB
 	select LEDS_GPIO_REGISTER
+	select BCM47XX_NVRAM
 	help
 	 Support for BCM47XX based boards
 

arch/mips/bcm47xx/Makefile

@@ -3,5 +3,5 @@
 # under Linux.
 #
 
-obj-y				+= irq.o nvram.o prom.o serial.o setup.o time.o sprom.o
+obj-y				+= irq.o prom.o serial.o setup.o time.o sprom.o
 obj-y				+= board.o buttons.o leds.o workarounds.o

drivers/firmware/Kconfig

@@ -136,6 +136,7 @@ config QCOM_SCM
 	bool
 	depends on ARM || ARM64
 
+source "drivers/firmware/broadcom/Kconfig"
 source "drivers/firmware/google/Kconfig"
 source "drivers/firmware/efi/Kconfig"
 

drivers/firmware/Makefile

@@ -14,6 +14,7 @@ obj-$(CONFIG_FIRMWARE_MEMMAP)	+= memmap.o
 obj-$(CONFIG_QCOM_SCM)		+= qcom_scm.o
 CFLAGS_qcom_scm.o :=$(call as-instr,.arch_extension sec,-DREQUIRES_SEC=1)
 
+obj-y				+= broadcom/
 obj-$(CONFIG_GOOGLE_FIRMWARE)	+= google/
 obj-$(CONFIG_EFI)		+= efi/
 obj-$(CONFIG_UEFI_CPER)		+= efi/

drivers/firmware/broadcom/Kconfig

+config BCM47XX_NVRAM
+	bool "Broadcom NVRAM driver"
+	depends on BCM47XX || ARCH_BCM_5301X
+	help
+	  Broadcom home routers contain flash partition called "nvram" with all
+	  important hardware configuration as well as some minor user setup.
+	  NVRAM partition contains a text-like data representing name=value
+	  pairs.
+	  This driver provides an easy way to get value of requested parameter.
+	  It simply reads content of NVRAM and parses it. It doesn't control any
+	  hardware part itself.

drivers/firmware/broadcom/Makefile

+obj-$(CONFIG_BCM47XX_NVRAM)		+= bcm47xx_nvram.o

arch/mips/bcm47xx/nvram.c → drivers/firmware/broadcom/bcm47xx_nvram.c

@@ -244,3 +244,5 @@ char *bcm47xx_nvram_get_contents(size_t *nvram_size)
 	return nvram;
 }
 EXPORT_SYMBOL(bcm47xx_nvram_get_contents);
+
+MODULE_LICENSE("GPLv2");

include/linux/bcm47xx_nvram.h

@@ -12,7 +12,7 @@
 #include <linux/kernel.h>
 #include <linux/vmalloc.h>
 
-#ifdef CONFIG_BCM47XX
+#ifdef CONFIG_BCM47XX_NVRAM
 int bcm47xx_nvram_init_from_mem(u32 base, u32 lim);
 int bcm47xx_nvram_getenv(const char *name, char *val, size_t val_len);
 int bcm47xx_nvram_gpio_pin(const char *name);