MIPS: BMIPS: Add Whirlwind (BMIPS5200) initialization code

Import bmips_5xxx_init.S from the stblinux-3.3 tree, and to make sure that this
would work nicely with a BMIPS multiplatform kernel (with BMIPS330, BMIPS43XX
and BMIPS5000 enabled), update soft_reset to check for the BMIPS5200 processor
id (PRID_IMP_BMIPS5200) and execute bmips_5xxx_init for these processors to
bring them online.

Tested on 7425, 7429 and 7435 with CPU hotplug. 7435 SMP still needs some
additional changes in the L1 interrupt area to work properly with interrupt
affinity.
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
Cc: linux-mips@linux-mips.org
Cc: john@phrozen.org
Cc: cernekee@gmail.com
Cc: jon.fraser@broadcom.com
Cc: jaedon.shin@gmail.com
Cc: dragan.stancevic@gmail.com
Cc: jogo@openwrt.org
Patchwork: https://patchwork.linux-mips.org/patch/12377/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

arch/mips/kernel/Makefile

@@ -44,7 +44,7 @@ obj-$(CONFIG_CPU_CAVIUM_OCTEON)	+= r4k_fpu.o octeon_switch.o
 
 obj-$(CONFIG_SMP)		+= smp.o
 obj-$(CONFIG_SMP_UP)		+= smp-up.o
-obj-$(CONFIG_CPU_BMIPS)		+= smp-bmips.o bmips_vec.o
+obj-$(CONFIG_CPU_BMIPS)		+= smp-bmips.o bmips_vec.o bmips_5xxx_init.o
 
 obj-$(CONFIG_MIPS_MT)		+= mips-mt.o
 obj-$(CONFIG_MIPS_MT_FPAFF)	+= mips-mt-fpaff.o

arch/mips/kernel/bmips_vec.S

@@ -88,7 +88,7 @@ NESTED(bmips_reset_nmi_vec, PT_SIZE, sp)
 	li	k1, (1 << 19)
 	mfc0	k0, CP0_STATUS
 	and	k0, k1
-	beqz	k0, bmips_smp_entry
+	beqz	k0, soft_reset
 
 #if defined(CONFIG_CPU_BMIPS5000)
 	mfc0	k0, CP0_PRID
@@ -126,13 +126,48 @@ NESTED(bmips_reset_nmi_vec, PT_SIZE, sp)
 	.set	arch=r4000
 	eret
 
+#ifdef CONFIG_SMP
+soft_reset:
+
+#if defined(CONFIG_CPU_BMIPS5000)
+	mfc0	k0, CP0_PRID
+	andi	k0, 0xff00
+	li	k1, PRID_IMP_BMIPS5200
+	bne	k0, k1, bmips_smp_entry
+
+        /* if running on TP 1, jump  to  bmips_smp_entry */
+        mfc0    k0, $22
+        li      k1, (1 << 24)
+        and     k1, k0
+        bnez    k1, bmips_smp_entry
+        nop
+
+        /*
+         * running on TP0, can not be core 0 (the boot core).
+         * Check for soft reset.  Indicates a warm boot
+         */
+        mfc0    k0, $12
+        li      k1, (1 << 20)
+        and     k0, k1
+        beqz    k0, bmips_smp_entry
+
+        /*
+         * Warm boot.
+         * Cache init is only done on TP0
+         */
+        la      k0, bmips_5xxx_init
+        jalr    k0
+        nop
+
+        b       bmips_smp_entry
+        nop
+#endif
+
 /***********************************************************************
  * CPU1 reset vector (used for the initial boot only)
  * This is still part of bmips_reset_nmi_vec().
  ***********************************************************************/
 
-#ifdef CONFIG_SMP
-
 bmips_smp_entry:
 
 	/* set up CP0 STATUS; enable FPU */