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#
# Copyright (c) 2005 Jakub Jermar
# Copyright (c) 2008 Pavel Rimsky
# All rights reserved.
#
# Redistribution and use in source and binary forms, with or without
# modification, are permitted provided that the following conditions
# are met:
#
# - Redistributions of source code must retain the above copyright
#   notice, this list of conditions and the following disclaimer.
# - Redistributions in binary form must reproduce the above copyright
#   notice, this list of conditions and the following disclaimer in the
#   documentation and/or other materials provided with the distribution.
# - The name of the author may not be used to endorse or promote products
#   derived from this software without specific prior written permission.
#
# THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
# IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
# OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
# IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
# INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
# NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
# DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
# THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
# (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
# THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
#

#include <arch/arch.h>
#include <arch/stack.h>
#include <arch/sun4v/regdef.h>
#include <arch/sun4v/hypercall.h>
#include <arch/mm/pagesize.h>
#include <arch/mm/sun4v/tte.h>
#include <arch/mm/sun4v/mmu.h>
#include <arch/mm/sun4v/tlb.h>

.register %g2, #scratch
.register %g3, #scratch

.section K_TEXT_START, "ax"

#define BSP_FLAG        1
#define PHYSMEM_ADDR_SIZE   56

/*
 * Flags set in the TTE data entry mapping the kernel.
 */
#ifdef CONFIG_VIRT_IDX_DCACHE
    #define TTE_FLAGS \
        (1 << TTE_V_SHIFT) \
        | (1 << TTE_EP_SHIFT) \
        | (1 << TTE_CP_SHIFT) \
        | (1 << TTE_CV_SHIFT) \
        | (1 << TTE_P_SHIFT) \
        | (1 << TTE_W_SHIFT)
#else
    #define TTE_FLAGS \
        (1 << TTE_V_SHIFT) \
        | (1 << TTE_EP_SHIFT) \
        | (1 << TTE_CP_SHIFT) \
        | (1 << TTE_P_SHIFT) \
        | (1 << TTE_W_SHIFT)
#endif


/*
 * Fills a register with a TTE Data item. The item will map the given virtual
 * address to a real address which will be computed by adding the starting
 * address of the physical memory to the virtual address.
 *
 * parameters:
 *  addr:           virtual address to be mapped
 *  rphysmem_start:     register containing the starting address of the
 *              physical memory
 *  rtmp1:          a register to be used as temporary
 *  rtmp2:          a register to be used as temporary
 *  rd:         register where the result will be saved
 */
#define TTE_DATA(addr, rphysmem_start, rtmp1, rtmp2, rd) \
    setx TTE_FLAGS | PAGESIZE_4M, rtmp1, rd; \
    add rd, rphysmem_start, rd; \
    setx (addr), rtmp1, rtmp2; \
    add rd, rtmp2, rd;

/*
 * Here is where the kernel is passed control from the boot loader.
 * 
 * The registers are expected to be in this state:
 * - %o0 starting address of physical memory + bootstrap processor flag
 *  bits 63...1:    physical memory starting address / 2
 *  bit 0:      non-zero on BSP processor, zero on AP processors
 * - %o1 bootinfo structure address (BSP only)
 * - %o2 bootinfo structure size (BSP only)
 *
 * Moreover, we depend on boot having established the following environment:
 * - TLBs are on
 * - identity mapping for the kernel image
 */
.global kernel_image_start
kernel_image_start:
    mov BSP_FLAG, %l0
    and %o0, %l0, %l7           ! l7 <= bootstrap processor?
    andn %o0, %l0, %l6          ! l6 <= start of physical memory
    or %o1, %g0, %l1
    or %o2, %g0, %l2

    ! Get bits (PHYSMEM_ADDR_SIZE - 1):13 of physmem_base.
    srlx %l6, 13, %l5
    
    ! l5 <= physmem_base[(PHYSMEM_ADDR_SIZE - 1):13]
    sllx %l5, 13 + (63 - (PHYSMEM_ADDR_SIZE - 1)), %l5
    srlx %l5, 63 - (PHYSMEM_ADDR_SIZE - 1), %l5 

    /*
     * Setup basic runtime environment.
     */
    wrpr %g0, NWINDOWS - 2, %cansave    ! set maximum saveable windows
    wrpr %g0, 0, %canrestore        ! get rid of windows we will
                        ! never need again
    wrpr %g0, 0, %otherwin          ! make sure the window state is
                        ! consistent
    wrpr %g0, NWINDOWS - 1, %cleanwin   ! prevent needless clean_window
                        ! traps for kernel
                        
    wrpr %g0, 0, %wstate            ! use default spill/fill trap

    wrpr %g0, 0, %tl            ! TL = 0, primary context
                        ! register is used

    wrpr %g0, PSTATE_PRIV_BIT, %pstate  ! disable interrupts and disable
                        ! 32-bit address masking

    wrpr %g0, 0, %pil           ! intialize %pil

    /*
     * Switch to kernel trap table.
     */
    sethi %hi(trap_table), %g1
    wrpr %g1, %lo(trap_table), %tba


    /*
     * Take over the MMU.
     */

    ! map kernel in context 1
    set kernel_image_start, %o0             ! virt. address
    set 1, %o1                      ! context
    TTE_DATA(kernel_image_start, %l5, %g2, %g3, %o2)    ! TTE data
    set MMU_FLAG_DTLB | MMU_FLAG_ITLB, %o3          ! MMU flags
    __HYPERCALL_HYPERFAST(MMU_MAP_ADDR)

    ! switch to context 1
    set 1, %o0
    set VA_PRIMARY_CONTEXT_REG, %o1
    stxa %o0, [%o1] ASI_PRIMARY_CONTEXT_REG

    ! demap all in context 0
    set 0, %o0                      ! reserved
    set 0, %o1                      ! reserved
    set 0, %o2                      ! context
    set MMU_FLAG_DTLB | MMU_FLAG_ITLB, %o3          ! MMU flags
    __HYPERCALL_FAST(MMU_DEMAP_CTX)

    ! install permanent mapping for kernel in context 0
    set kernel_image_start, %o0             ! virtual address
    set 0, %o1                      ! context
    TTE_DATA(kernel_image_start, %l5, %g2, %g3, %o2)    ! TTE data
    set MMU_FLAG_DTLB | MMU_FLAG_ITLB, %o3          ! MMU flags
    __HYPERCALL_FAST(MMU_MAP_PERM_ADDR)

    ! switch to context 0
    mov 0, %o0
    set VA_PRIMARY_CONTEXT_REG, %o1
    stxa %o0, [%o1] ASI_PRIMARY_CONTEXT_REG

    ! demap all in context 1 (cleanup)
    set 0, %o0                      ! reserved
    set 0, %o1                      ! reserved
    set 1, %o2                      ! context
    set MMU_FLAG_DTLB | MMU_FLAG_ITLB, %o3          ! MMU flags
    __HYPERCALL_FAST(MMU_DEMAP_CTX)
    
    /*
     * Save physmem_base for use by the mm subsystem.
     * %l6 contains starting physical address
     */
    sethi %hi(physmem_base), %l4
    stx %l6, [%l4 + %lo(physmem_base)]

    /*
     * So far, we have not touched the stack.
     * It is a good idea to set the kernel stack to a known state now.
     */
    sethi %hi(temporary_boot_stack), %sp
    or %sp, %lo(temporary_boot_stack), %sp
    sub %sp, STACK_BIAS, %sp

    or %l1, %g0, %o1
    or %l2, %g0, %o2
    sethi %hi(bootinfo), %o0
    call memcpy             ! copy bootinfo
    or %o0, %lo(bootinfo), %o0

    call arch_pre_main
    nop
    
    call main_bsp
    nop

    /* Not reached. */

0:
    ba 0b
    nop

.section K_DATA_START, "aw", @progbits

#define INITIAL_STACK_SIZE      1024

.align STACK_ALIGNMENT
    .space INITIAL_STACK_SIZE
.align STACK_ALIGNMENT
temporary_boot_stack:
    .space STACK_WINDOW_SAVE_AREA_SIZE


.data

.align 8
.global physmem_base        ! copy of the physical memory base address
physmem_base:
    .quad 0