MIPS: add initial infrastructure for Broadcom MIPS SoCs

CFE checks CPU Thread in a different way (using register $22):
mfc0	t1, C0_BCM_CONFIG, 3 # $22
li	t2, CP0_CMT_TPID # (1 << 31)
and	t1, t2
bnez	t1, 2f	# if we are running on thread 1, skip init
nop

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
Reviewed-by: Simon Glass <sjg@chromium.org>

arch/mips/Kconfig

@@ -75,6 +75,15 @@ config ARCH_ATH79
 	select OF_CONTROL
 	select DM
 
+config ARCH_BMIPS
+	bool "Support BMIPS SoCs"
+	select OF_CONTROL
+	select DM
+	select CLK
+	select CPU
+	select RAM
+	select SYSRESET
+
 config MACH_PIC32
 	bool "Support Microchip PIC32"
 	select OF_CONTROL
@@ -123,6 +132,7 @@ source "board/micronas/vct/Kconfig"
 source "board/pb1x00/Kconfig"
 source "board/qemu-mips/Kconfig"
 source "arch/mips/mach-ath79/Kconfig"
+source "arch/mips/mach-bmips/Kconfig"
 source "arch/mips/mach-pic32/Kconfig"
 
 if MIPS

arch/mips/Makefile

@@ -15,6 +15,7 @@ libs-y += arch/mips/lib/
 
 machine-$(CONFIG_SOC_AU1X00) += au1x00
 machine-$(CONFIG_ARCH_ATH79) += ath79
+machine-$(CONFIG_ARCH_BMIPS) += bmips
 machine-$(CONFIG_MACH_PIC32) += pic32
 
 machdirs := $(patsubst %,arch/mips/mach-%/,$(machine-y))

arch/mips/cpu/start.S

@@ -151,8 +151,13 @@ reset:
 	 mfc0	t0, CP0_GLOBALNUMBER
 #endif
 
+#ifdef CONFIG_ARCH_BMIPS
+1:	mfc0	t0, CP0_DIAGNOSTIC, 3
+	and	t0, t0, (1 << 31)
+#else
 1:	mfc0	t0, CP0_EBASE
 	and	t0, t0, EBASE_CPUNUM
+#endif
 
 	/* Hang if this isn't the first CPU in the system */
 2:	beqz	t0, 4f

arch/mips/mach-bmips/Kconfig

@@ -0,0 +1,23 @@
+menu "Broadcom MIPS platforms"
+	depends on ARCH_BMIPS
+
+config SYS_SOC
+	default "none"
+
+choice
+	prompt "Boot mode"
+
+config BMIPS_BOOT_RAM
+	bool "RAM boot"
+	depends on BMIPS_SUPPORTS_BOOT_RAM
+	help
+	  This builds an image that is linked to a RAM address. It can be used
+	  for booting from CFE via TFTP using an ELF image, but it can also be
+	  booted from RAM by other bootloaders using a BIN image.
+
+endchoice
+
+config BMIPS_SUPPORTS_BOOT_RAM
+	bool
+
+endmenu

arch/mips/mach-bmips/Makefile

@@ -0,0 +1,5 @@
+#
+# SPDX-License-Identifier:	GPL-2.0+
+#
+
+obj-y += dram.o

arch/mips/mach-bmips/dram.c

@@ -0,0 +1,37 @@
+/*
+ * Copyright (C) 2016 Daniel Schwierzeck <daniel.schwierzeck@gmail.com>
+ * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#include <common.h>
+#include <ram.h>
+#include <dm.h>
+
+DECLARE_GLOBAL_DATA_PTR;
+
+int dram_init(void)
+{
+	struct ram_info ram;
+	struct udevice *dev;
+	int err;
+
+	err = uclass_get_device(UCLASS_RAM, 0, &dev);
+	if (err) {
+		debug("DRAM init failed: %d\n", err);
+		return 0;
+	}
+
+	err = ram_get_info(dev, &ram);
+	if (err) {
+		debug("Cannot get DRAM size: %d\n", err);
+		return 0;
+	}
+
+	debug("SDRAM base=%zx, size=%x\n", ram.base, ram.size);
+
+	gd->ram_size = ram.size;
+
+	return 0;
+}

include/configs/bmips_common.h

@@ -0,0 +1,23 @@
+/*
+ * Copyright (C) 2017 Álvaro Fernández Rojas <noltari@gmail.com>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef __CONFIG_BMIPS_COMMON_H
+#define __CONFIG_BMIPS_COMMON_H
+
+/* RAM */
+#define CONFIG_SYS_MEMTEST_START	0xa0000000
+#define CONFIG_SYS_MEMTEST_END		0xa2000000
+
+/* Memory usage */
+#define CONFIG_SYS_MAXARGS		24
+#define CONFIG_SYS_MALLOC_LEN		(1024 * 1024)
+#define CONFIG_SYS_BOOTPARAMS_LEN	(128 * 1024)
+#define CONFIG_SYS_CBSIZE		512
+
+/* U-Boot */
+#define CONFIG_SYS_MONITOR_BASE		CONFIG_SYS_TEXT_BASE
+
+#endif /* __CONFIG_BMIPS_COMMON_H */