mips: octeon: lowlevel_init.S: Add NMI handling code for SMP Linux booting

This patch adds the necessary lowlevel init code, to enable SMP Linux
booting. This code will be used with the platform specific Octeon Linux
boot command "bootoctlinux", which starts a configurable number of cores
into Linux.

Additionally some erratas and lowlevel register initializations are
copied from the original Cavium / Marvell U-Boot source code, enabling
booting into the Linux kernel.

Signed-off-by: Stefan Roese <sr@denx.de>

diff --git a/arch/mips/mach-octeon/lowlevel_init.S b/arch/mips/mach-octeon/lowlevel_init.S
index fa87cb4..56d1d22 100644 (file)
--- a/arch/mips/mach-octeon/lowlevel_init.S
+++ b/arch/mips/mach-octeon/lowlevel_init.S
@@ -10,10 +10,36 @@
 #include <asm/mipsregs.h>
 #include <asm/addrspace.h>
 #include <asm/asm.h>
+#include <mach/octeon-model.h>
+
+#define COP0_CVMCTL_REG                $9,7    /* Cavium control */
+#define COP0_CVMMEMCTL_REG     $11,7   /* Cavium memory control */
+#define COP0_PROC_ID_REG       $15,0
 
        .set noreorder
 
 LEAF(lowlevel_init)
+
+       /* Set LMEMSZ in CVMMEMCTL register */
+       dmfc0   a0, COP0_CVMMEMCTL_REG
+       dins    a0, zero, 0, 9
+       mfc0    a4, COP0_PROC_ID_REG
+       li      a5, OCTEON_CN63XX_PASS1_0 /* Octeon cn63xx pass1 chip id */
+       bgt     a5, a4, 2f
+        ori     a0, 0x104      /* setup 4 lines of scratch */
+       ori     a6, a5, 8       /* Octeon cn63xx pass2 chip id */
+       bge     a4, a6, 2f
+        nop
+       li      a6, 4
+       ins     a0, a6, 11, 4   /* Set WBTHRESH=4 as per Core-14752 errata */
+2:
+       dmtc0   a0, COP0_CVMMEMCTL_REG
+
+       /* Set REPUN bit in CVMCTL register */
+       dmfc0   a0, COP0_CVMCTL_REG
+       ori     a0, 1<<14       /* enable fixup of unaligned mem access */
+       dmtc0   a0, COP0_CVMCTL_REG
+
        jr      ra
         nop
        END(lowlevel_init)
@@ -67,3 +93,53 @@ __dummy:
         nop
 
        END(mips_mach_early_init)
+
+LEAF(nmi_bootvector)
+
+       /*
+        * From Marvell original bootvector setup
+        */
+       mfc0    k0, CP0_STATUS
+       /* Enable 64-bit addressing, set ERL (should already be set) */
+       ori     k0, 0x84
+       mtc0    k0, CP0_STATUS
+       /* Core-14345, clear L1 Dcache virtual tags if the core hit an NMI */
+       cache   17, 0($0)
+
+       /*
+        * Needed for Linux kernel booting, otherwise it hangs while
+        * zero'ing all of CVMSEG
+        */
+       dmfc0   a0, COP0_CVMMEMCTL_REG
+       dins    a0, zero, 0, 9
+       ori     a0, 0x104       /* setup 4 lines of scratch */
+       dmtc0   a0, COP0_CVMMEMCTL_REG
+
+       /*
+        * Load parameters and entry point
+        */
+       PTR_LA  t9, nmi_handler_para
+       sync
+
+       ld      s0, 0x00(t9)
+       ld      a0, 0x08(t9)
+       ld      a1, 0x10(t9)
+       ld      a2, 0x18(t9)
+       ld      a3, 0x20(t9)
+
+       /* Finally jump to entry point (start kernel etc) */
+       j       s0
+        nop
+
+       END(nmi_bootvector)
+
+       /*
+        * Add here some space for the NMI parameters (entry point and args)
+        */
+       .globl nmi_handler_para
+nmi_handler_para:
+       .dword  0       // entry-point
+       .dword  0       // arg0
+       .dword  0       // arg1
+       .dword  0       // arg2
+       .dword  0       // arg3