MIPS: BCM47xx: Move SPROM driver to drivers/firmware/

Broadcom ARM home routers store SPROM content in NVRAM just like MIPS
ones. To share SPROM code we need to move it out of arch/mips/ to some
common place. We already have bcm47xx_nvram in firmware path and SPROM
should fit there as well.
This driver is responsible for parsing SoC configuration data into a
struct shared between ssb and bcma buses.
This was tested with BCM4706 & BCM5357C0 (BCM47XX) and BCM4708A0
(ARCH_BCM_5301X).

Signed-off-by: Rafał Miłecki <zajec5@gmail.com>
Cc: Hauke Mehrtens <hauke@hauke-m.de>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/12210/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/Kconfig

@@ -197,6 +197,7 @@ config BCM47XX
 	select GPIOLIB
 	select LEDS_GPIO_REGISTER
 	select BCM47XX_NVRAM
+	select BCM47XX_SPROM
 	help
 	 Support for BCM47XX based boards
 

arch/mips/bcm47xx/Makefile

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

arch/mips/bcm47xx/bcm47xx_private.h

@@ -10,9 +10,6 @@
 /* prom.c */
 void __init bcm47xx_prom_highmem_init(void);
 
-/* sprom.c */
-void bcm47xx_sprom_register_fallbacks(void);
-
 /* buttons.c */
 int __init bcm47xx_buttons_register(void);
 

arch/mips/bcm47xx/setup.c

@@ -28,6 +28,7 @@
 
 #include "bcm47xx_private.h"
 
+#include <linux/bcm47xx_sprom.h>
 #include <linux/export.h>
 #include <linux/types.h>
 #include <linux/ethtool.h>
@@ -151,7 +152,6 @@ void __init plat_mem_setup(void)
 		pr_info("Using bcma bus\n");
 #ifdef CONFIG_BCM47XX_BCMA
 		bcm47xx_bus_type = BCM47XX_BUS_TYPE_BCMA;
-		bcm47xx_sprom_register_fallbacks();
 		bcm47xx_register_bcma();
 		bcm47xx_set_system_type(bcm47xx_bus.bcma.bus.chipinfo.id);
 #ifdef CONFIG_HIGHMEM

drivers/firmware/broadcom/Kconfig

@@ -9,3 +9,14 @@ config BCM47XX_NVRAM
 	  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.
+
+config BCM47XX_SPROM
+	bool "Broadcom SPROM driver"
+	depends on BCM47XX_NVRAM
+	help
+	  Broadcom devices store configuration data in SPROM. Accessing it is
+	  specific to the bus host type, e.g. PCI(e) devices have it mapped in
+	  a PCI BAR.
+	  In case of SoC devices SPROM content is stored on a flash used by
+	  bootloader firmware CFE. This driver provides method to ssb and bcma
+	  drivers to read SPROM on SoC.

drivers/firmware/broadcom/Makefile

@@ -1 +1,2 @@
 obj-$(CONFIG_BCM47XX_NVRAM)		+= bcm47xx_nvram.o
+obj-$(CONFIG_BCM47XX_SPROM)		+= bcm47xx_sprom.o

arch/mips/bcm47xx/sprom.c → drivers/firmware/broadcom/bcm47xx_sprom.c

@@ -26,9 +26,11 @@
  *  675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include <bcm47xx.h>
-#include <linux/if_ether.h>
+#include <linux/bcm47xx_nvram.h>
+#include <linux/bcma/bcma.h>
 #include <linux/etherdevice.h>
+#include <linux/if_ether.h>
+#include <linux/ssb/ssb.h>
 
 static void create_key(const char *prefix, const char *postfix,
 		       const char *name, char *buf, int len)
@@ -599,7 +601,7 @@ void bcm47xx_fill_sprom(struct ssb_sprom *sprom, const char *prefix,
 	bcm47xx_sprom_fill_auto(sprom, prefix, fallback);
 }
 
-#if defined(CONFIG_BCM47XX_SSB)
+#if IS_BUILTIN(CONFIG_SSB) && IS_ENABLED(CONFIG_SSB_SPROM)
 static int bcm47xx_get_sprom_ssb(struct ssb_bus *bus, struct ssb_sprom *out)
 {
 	char prefix[10];
@@ -622,7 +624,7 @@ static int bcm47xx_get_sprom_ssb(struct ssb_bus *bus, struct ssb_sprom *out)
 }
 #endif
 
-#if defined(CONFIG_BCM47XX_BCMA)
+#if IS_BUILTIN(CONFIG_BCMA)
 /*
  * Having many NVRAM entries for PCI devices led to repeating prefixes like
  * pci/1/1/ all the time and wasting flash space. So at some point Broadcom
@@ -706,19 +708,30 @@ static int bcm47xx_get_sprom_bcma(struct bcma_bus *bus, struct ssb_sprom *out)
 }
 #endif
 
+static unsigned int bcm47xx_sprom_registered;
+
 /*
  * On bcm47xx we need to register SPROM fallback handler very early, so we can't
  * use anything like platform device / driver for this.
  */
-void bcm47xx_sprom_register_fallbacks(void)
+int bcm47xx_sprom_register_fallbacks(void)
 {
-#if defined(CONFIG_BCM47XX_SSB)
+	if (bcm47xx_sprom_registered)
+		return 0;
+
+#if IS_BUILTIN(CONFIG_SSB) && IS_ENABLED(CONFIG_SSB_SPROM)
 	if (ssb_arch_register_fallback_sprom(&bcm47xx_get_sprom_ssb))
 		pr_warn("Failed to register ssb SPROM handler\n");
 #endif
 
-#if defined(CONFIG_BCM47XX_BCMA)
+#if IS_BUILTIN(CONFIG_BCMA)
 	if (bcma_arch_register_fallback_sprom(&bcm47xx_get_sprom_bcma))
 		pr_warn("Failed to register bcma SPROM handler\n");
 #endif
+
+	bcm47xx_sprom_registered = 1;
+
+	return 0;
 }
+
+fs_initcall(bcm47xx_sprom_register_fallbacks);

include/linux/bcm47xx_sprom.h

@@ -0,0 +1,24 @@
+/*
+ *  This program is free software; you can redistribute  it and/or modify it
+ *  under  the terms of  the GNU General  Public License as published by the
+ *  Free Software Foundation;  either version 2 of the  License, or (at your
+ *  option) any later version.
+ */
+
+#ifndef __BCM47XX_SPROM_H
+#define __BCM47XX_SPROM_H
+
+#include <linux/types.h>
+#include <linux/kernel.h>
+#include <linux/vmalloc.h>
+
+#ifdef CONFIG_BCM47XX_SPROM
+int bcm47xx_sprom_register_fallbacks(void);
+#else
+static inline int bcm47xx_sprom_register_fallbacks(void)
+{
+	return -ENOTSUPP;
+};
+#endif
+
+#endif /* __BCM47XX_SPROM_H */