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// SPDX-License-Identifier: GPL-2.0
// Copyright (C) 2005-2017 Andes Technology Corporation
#include <linux/linkage.h>
#include <linux/init.h>
#include <asm/ptrace.h>
#include <asm/asm-offsets.h>
#include <asm/page.h>
#include <asm/pgtable.h>
#include <asm/sizes.h>
#include <asm/thread_info.h>
#ifdef CONFIG_CPU_BIG_ENDIAN
#define OF_DT_MAGIC 0xd00dfeed
#else
#define OF_DT_MAGIC 0xedfe0dd0
#endif
.globl swapper_pg_dir
.equ swapper_pg_dir, TEXTADDR - 0x4000
/*
* Kernel startup entry point.
*/
.section ".head.text", "ax"
.type _stext, %function
ENTRY(_stext)
setgie.d ! Disable interrupt
isb
/*
* Disable I/D-cache and enable it at a proper time
*/
mfsr $r0, $mr8
li $r1, #~(CACHE_CTL_mskIC_EN|CACHE_CTL_mskDC_EN)
and $r0, $r0, $r1
mtsr $r0, $mr8
/*
* Process device tree blob
*/
andi $r0,$r2,#0x3
li $r10, 0
bne $r0, $r10, _nodtb
lwi $r0, [$r2]
li $r1, OF_DT_MAGIC
bne $r0, $r1, _nodtb
move $r10, $r2
_nodtb:
/*
* Create a temporary mapping area for booting, before start_kernel
*/
sethi $r4, hi20(swapper_pg_dir)
li $p0, (PAGE_OFFSET - PHYS_OFFSET)
sub $r4, $r4, $p0
tlbop FlushAll ! invalidate TLB\n"
isb
mtsr $r4, $L1_PPTB ! load page table pointer\n"
/* set NTC0 cacheable/writeback, mutliple page size in use */
mfsr $r3, $MMU_CTL
li $r0, #~MMU_CTL_mskNTC0
and $r3, $r3, $r0
#ifdef CONFIG_ANDES_PAGE_SIZE_4KB
ori $r3, $r3, #(MMU_CTL_mskMPZIU|(MMU_CTL_CACHEABLE_WB << MMU_CTL_offNTC0))
#else
ori $r3, $r3, #(MMU_CTL_mskMPZIU|(MMU_CTL_CACHEABLE_WB << MMU_CTL_offNTC0)|MMU_CTL_D8KB)
#endif
#ifdef CONFIG_HW_SUPPORT_UNALIGNMENT_ACCESS
li $r0, #MMU_CTL_UNA
or $r3, $r3, $r0
#endif
mtsr $r3, $MMU_CTL
isb
/* set page size and size of kernel image */
mfsr $r0, $MMU_CFG
srli $r3, $r0, MMU_CFG_offfEPSZ
zeb $r3, $r3
bnez $r3, _extra_page_size_support
#ifdef CONFIG_ANDES_PAGE_SIZE_4KB
li $r5, #SZ_4K ! Use 4KB page size
#else
li $r5, #SZ_8K ! Use 8KB page size
li $r3, #1
#endif
mtsr $r3, $TLB_MISC
b _image_size_check
_extra_page_size_support: ! Use epzs pages size
clz $r6, $r3
subri $r2, $r6, #31
li $r3, #1
sll $r3, $r3, $r2
/* MMU_CFG.EPSZ value -> meaning */
mul $r5, $r3, $r3
slli $r5, $r5, #14
/* MMU_CFG.EPSZ -> TLB_MISC.ACC_PSZ */
addi $r3, $r2, #0x2
mtsr $r3, $TLB_MISC
_image_size_check:
/* calculate the image maximum size accepted by TLB config */
andi $r6, $r0, MMU_CFG_mskTBW
andi $r0, $r0, MMU_CFG_mskTBS
srli $r6, $r6, MMU_CFG_offTBW
srli $r0, $r0, MMU_CFG_offTBS
/*
* we just map the kernel to the maximum way - 1 of tlb
* reserver one way for UART VA mapping
* it will cause page fault if UART mapping cover the kernel mapping
*
* direct mapping is not supported now.
*/
li $r2, 't'
beqz $r6, __error ! MMU_CFG.TBW = 0 is direct mappin
addi $r0, $r0, #0x2 ! MMU_CFG.TBS value -> meaning
sll $r0, $r6, $r0 ! entries = k-way * n-set
mul $r6, $r0, $r5 ! max size = entries * page size
/* check kernel image size */
la $r3, (_end - PAGE_OFFSET)
li $r2, 's'
bgt $r3, $r6, __error
li $r2, #(PHYS_OFFSET + TLB_DATA_kernel_text_attr)
li $r3, PAGE_OFFSET
add $r6, $r6, $r3
_tlb:
mtsr $r3, $TLB_VPN
dsb
tlbop $r2, RWR
isb
add $r3, $r3, $r5
add $r2, $r2, $r5
bgt $r6, $r3, _tlb
mfsr $r3, $TLB_MISC ! setup access page size
li $r2, #~0xf
and $r3, $r3, $r2
#ifdef CONFIG_ANDES_PAGE_SIZE_8KB
ori $r3, $r3, #0x1
#endif
mtsr $r3, $TLB_MISC
mfsr $r0, $MISC_CTL ! Enable BTB and RTP and shadow sp
ori $r0, $r0, #MISC_init
mtsr $r0, $MISC_CTL
mfsr $p1, $PSW
li $r15, #~PSW_clr ! clear WBNA|DME|IME|DT|IT|POM|INTL|GIE
and $p1, $p1, $r15
ori $p1, $p1, #PSW_init
mtsr $p1, $IPSW ! when iret, it will automatically enable MMU
la $lp, __mmap_switched
mtsr $lp, $IPC
iret
nop
.type __switch_data, %object
__switch_data:
.long __bss_start ! $r6
.long _end ! $r7
.long __atags_pointer ! $atag_pointer
.long init_task ! $r9, move to $r25
.long init_thread_union + THREAD_SIZE ! $sp
/*
* The following fragment of code is executed with the MMU on in MMU mode,
* and uses absolute addresses; this is not position independent.
*/
.align
.type __mmap_switched, %function
__mmap_switched:
la $r3, __switch_data
lmw.bim $r6, [$r3], $r9, #0b0001
move $r25, $r9
move $fp, #0 ! Clear BSS (and zero $fp)
beq $r7, $r6, _RRT
1: swi.bi $fp, [$r6], #4
bne $r7, $r6, 1b
swi $r10, [$r8]
_RRT:
b start_kernel
__error:
b __error
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