MIPS: BMIPS: Add SMP support code for BMIPS43xx/BMIPS5000
Initial commit of BMIPS SMP support code. Smoke-tested on a variety of
BMIPS4350, BMIPS4380, and BMIPS5000 platforms.
Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: linux-mips@linux-mips.org
Patchwork: https://patchwork.linux-mips.org/patch/2977/
Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
diff --git a/arch/mips/kernel/bmips_vec.S b/arch/mips/kernel/bmips_vec.S
new file mode 100644
index 0000000..e908e81
--- /dev/null
+++ b/arch/mips/kernel/bmips_vec.S
@@ -0,0 +1,255 @@
+/*
+ * This file is subject to the terms and conditions of the GNU General Public
+ * License. See the file "COPYING" in the main directory of this archive
+ * for more details.
+ *
+ * Copyright (C) 2011 by Kevin Cernekee (cernekee@gmail.com)
+ *
+ * Reset/NMI/re-entry vectors for BMIPS processors
+ */
+
+#include <linux/init.h>
+
+#include <asm/asm.h>
+#include <asm/asmmacro.h>
+#include <asm/cacheops.h>
+#include <asm/regdef.h>
+#include <asm/mipsregs.h>
+#include <asm/stackframe.h>
+#include <asm/addrspace.h>
+#include <asm/hazards.h>
+#include <asm/bmips.h>
+
+ .macro BARRIER
+ .set mips32
+ _ssnop
+ _ssnop
+ _ssnop
+ .set mips0
+ .endm
+
+ __CPUINIT
+
+/***********************************************************************
+ * Alternate CPU1 startup vector for BMIPS4350
+ *
+ * On some systems the bootloader has already started CPU1 and configured
+ * it to resume execution at 0x8000_0200 (!BEV IV vector) when it is
+ * triggered by the SW1 interrupt. If that is the case we try to move
+ * it to a more convenient place: BMIPS_WARM_RESTART_VEC @ 0x8000_0380.
+ ***********************************************************************/
+
+LEAF(bmips_smp_movevec)
+ la k0, 1f
+ li k1, CKSEG1
+ or k0, k1
+ jr k0
+
+1:
+ /* clear IV, pending IPIs */
+ mtc0 zero, CP0_CAUSE
+
+ /* re-enable IRQs to wait for SW1 */
+ li k0, ST0_IE | ST0_BEV | STATUSF_IP1
+ mtc0 k0, CP0_STATUS
+
+ /* set up CPU1 CBR; move BASE to 0xa000_0000 */
+ li k0, 0xff400000
+ mtc0 k0, $22, 6
+ li k1, CKSEG1 | BMIPS_RELO_VECTOR_CONTROL_1
+ or k0, k1
+ li k1, 0xa0080000
+ sw k1, 0(k0)
+
+ /* wait here for SW1 interrupt from bmips_boot_secondary() */
+ wait
+
+ la k0, bmips_reset_nmi_vec
+ li k1, CKSEG1
+ or k0, k1
+ jr k0
+END(bmips_smp_movevec)
+
+/***********************************************************************
+ * Reset/NMI vector
+ * For BMIPS processors that can relocate their exception vectors, this
+ * entire function gets copied to 0x8000_0000.
+ ***********************************************************************/
+
+NESTED(bmips_reset_nmi_vec, PT_SIZE, sp)
+ .set push
+ .set noat
+ .align 4
+
+#ifdef CONFIG_SMP
+ /* if the NMI bit is clear, assume this is a CPU1 reset instead */
+ li k1, (1 << 19)
+ mfc0 k0, CP0_STATUS
+ and k0, k1
+ beqz k0, bmips_smp_entry
+
+#if defined(CONFIG_CPU_BMIPS5000)
+ /* if we're not on core 0, this must be the SMP boot signal */
+ li k1, (3 << 25)
+ mfc0 k0, $22
+ and k0, k1
+ bnez k0, bmips_smp_entry
+#endif
+#endif /* CONFIG_SMP */
+
+ /* nope, it's just a regular NMI */
+ SAVE_ALL
+ move a0, sp
+
+ /* clear EXL, ERL, BEV so that TLB refills still work */
+ mfc0 k0, CP0_STATUS
+ li k1, ST0_ERL | ST0_EXL | ST0_BEV | ST0_IE
+ or k0, k1
+ xor k0, k1
+ mtc0 k0, CP0_STATUS
+ BARRIER
+
+ /* jump to the NMI handler function */
+ la k0, nmi_handler
+ jr k0
+
+ RESTORE_ALL
+ .set mips3
+ eret
+
+/***********************************************************************
+ * 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 */
+ li k0, 0x30000000
+ mtc0 k0, CP0_STATUS
+ BARRIER
+
+ /* set local CP0 CONFIG to make kseg0 cacheable, write-back */
+ mfc0 k0, CP0_CONFIG
+ ori k0, 0x07
+ xori k0, 0x04
+ mtc0 k0, CP0_CONFIG
+
+#if defined(CONFIG_CPU_BMIPS4350) || defined(CONFIG_CPU_BMIPS4380)
+ /* initialize CPU1's local I-cache */
+ li k0, 0x80000000
+ li k1, 0x80010000
+ mtc0 zero, $28
+ mtc0 zero, $28, 1
+ BARRIER
+
+1: cache Index_Store_Tag_I, 0(k0)
+ addiu k0, 16
+ bne k0, k1, 1b
+#elif defined(CONFIG_CPU_BMIPS5000)
+ /* set exception vector base */
+ la k0, ebase
+ lw k0, 0(k0)
+ mtc0 k0, $15, 1
+ BARRIER
+#endif
+
+ /* jump back to kseg0 in case we need to remap the kseg1 area */
+ la k0, 1f
+ jr k0
+1:
+ la k0, bmips_enable_xks01
+ jalr k0
+
+ /* use temporary stack to set up upper memory TLB */
+ li sp, BMIPS_WARM_RESTART_VEC
+ la k0, plat_wired_tlb_setup
+ jalr k0
+
+ /* switch to permanent stack and continue booting */
+
+ .global bmips_secondary_reentry
+bmips_secondary_reentry:
+ la k0, bmips_smp_boot_sp
+ lw sp, 0(k0)
+ la k0, bmips_smp_boot_gp
+ lw gp, 0(k0)
+ la k0, start_secondary
+ jr k0
+
+#endif /* CONFIG_SMP */
+
+ .align 4
+ .global bmips_reset_nmi_vec_end
+bmips_reset_nmi_vec_end:
+
+END(bmips_reset_nmi_vec)
+
+ .set pop
+ .previous
+
+/***********************************************************************
+ * CPU1 warm restart vector (used for second and subsequent boots).
+ * Also used for S2 standby recovery (PM).
+ * This entire function gets copied to (BMIPS_WARM_RESTART_VEC)
+ ***********************************************************************/
+
+LEAF(bmips_smp_int_vec)
+
+ .align 4
+ mfc0 k0, CP0_STATUS
+ ori k0, 0x01
+ xori k0, 0x01
+ mtc0 k0, CP0_STATUS
+ eret
+
+ .align 4
+ .global bmips_smp_int_vec_end
+bmips_smp_int_vec_end:
+
+END(bmips_smp_int_vec)
+
+/***********************************************************************
+ * XKS01 support
+ * Certain CPUs support extending kseg0 to 1024MB.
+ ***********************************************************************/
+
+ __CPUINIT
+
+LEAF(bmips_enable_xks01)
+
+#if defined(CONFIG_XKS01)
+
+#if defined(CONFIG_CPU_BMIPS4380)
+ mfc0 t0, $22, 3
+ li t1, 0x1ff0
+ li t2, (1 << 12) | (1 << 9)
+ or t0, t1
+ xor t0, t1
+ or t0, t2
+ mtc0 t0, $22, 3
+ BARRIER
+#elif defined(CONFIG_CPU_BMIPS5000)
+ mfc0 t0, $22, 5
+ li t1, 0x01ff
+ li t2, (1 << 8) | (1 << 5)
+ or t0, t1
+ xor t0, t1
+ or t0, t2
+ mtc0 t0, $22, 5
+ BARRIER
+#else
+
+#error Missing XKS01 setup
+
+#endif
+
+#endif /* defined(CONFIG_XKS01) */
+
+ jr ra
+
+END(bmips_enable_xks01)
+
+ .previous