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head.S
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/* SPDX-License-Identifier: GPL-2.0-or-later
** -*- mode: asm -*-
**
** head.S -- This file contains the initial boot code for the
** Linux/68k kernel.
**
** Copyright 1993 by Hamish Macdonald
**
** 68040 fixes by Michael Rausch
** 68060 fixes by Roman Hodek
** MMU cleanup by Randy Thelen
** Final MMU cleanup by Roman Zippel
**
** Atari support by Andreas Schwab, using ideas of Robert de Vries
** and Bjoern Brauel
** VME Support by Richard Hirst
**
** 94/11/14 Andreas Schwab: put kernel at PAGESIZE
** 94/11/18 Andreas Schwab: remove identity mapping of STRAM for Atari
** ++ Bjoern & Roman: ATARI-68040 support for the Medusa
** 95/11/18 Richard Hirst: Added MVME166 support
** 96/04/26 Guenther Kelleter: fixed identity mapping for Falcon with
** Magnum- and FX-alternate ram
** 98/04/25 Phil Blundell: added HP300 support
** 1998/08/30 David Kilzer: Added support for font_desc structures
** for linux-2.1.115
** 1999/02/11 Richard Zidlicky: added Q40 support (initial version 99/01/01)
** 2004/05/13 Kars de Jong: Finalised HP300 support
*/
/*
* Linux startup code.
*
* At this point, the boot loader has:
* Disabled interrupts
* Disabled caches
* Put us in supervisor state.
*
* The kernel setup code takes the following steps:
* . Raise interrupt level
* . Set up initial kernel memory mapping.
* . This sets up a mapping of the 4M of memory the kernel is located in.
* . It also does a mapping of any initial machine specific areas.
* . Enable the MMU
* . Enable cache memories
* . Jump to kernel startup
*
* Much of the file restructuring was to accomplish:
* 1) Remove register dependency through-out the file.
* 2) Increase use of subroutines to perform functions
* 3) Increase readability of the code
*
* Of course, readability is a subjective issue, so it will never be
* argued that that goal was accomplished. It was merely a goal.
* A key way to help make code more readable is to give good
* documentation. So, the first thing you will find is exhaustive
* write-ups on the structure of the file, and the features of the
* functional subroutines.
*
* General Structure:
* ------------------
* Without a doubt the single largest chunk of head.S is spent
* mapping the kernel and I/O physical space into the logical range
* for the kernel.
* There are new subroutines and data structures to make MMU
* support cleaner and easier to understand.
* First, you will find a routine call "mmu_map" which maps
* a logical to a physical region for some length given a cache
* type on behalf of the caller. This routine makes writing the
* actual per-machine specific code very simple.
* A central part of the code, but not a subroutine in itself,
* is the mmu_init code which is broken down into mapping the kernel
* (the same for all machines) and mapping machine-specific I/O
* regions.
* Also, there will be a description of engaging the MMU and
* caches.
* You will notice that there is a chunk of code which
* can emit the entire MMU mapping of the machine. This is present
* only in debug modes and can be very helpful.
* Further, there is a new console driver in head.S that is
* also only engaged in debug mode. Currently, it's only supported
* on the Macintosh class of machines. However, it is hoped that
* others will plug-in support for specific machines.
*
* ######################################################################
*
* mmu_map
* -------
* mmu_map was written for two key reasons. First, it was clear
* that it was very difficult to read the previous code for mapping
* regions of memory. Second, the Macintosh required such extensive
* memory allocations that it didn't make sense to propagate the
* existing code any further.
* mmu_map requires some parameters:
*
* mmu_map (logical, physical, length, cache_type)
*
* While this essentially describes the function in the abstract, you'll
* find more indepth description of other parameters at the implementation site.
*
* mmu_get_root_table_entry
* ------------------------
* mmu_get_ptr_table_entry
* -----------------------
* mmu_get_page_table_entry
* ------------------------
*
* These routines are used by other mmu routines to get a pointer into
* a table, if necessary a new table is allocated. These routines are working
* basically like pmd_alloc() and pte_alloc() in <asm/pgtable.h>. The root
* table needs of course only to be allocated once in mmu_get_root_table_entry,
* so that here also some mmu specific initialization is done. The second page
* at the start of the kernel (the first page is unmapped later) is used for
* the kernel_pg_dir. It must be at a position known at link time (as it's used
* to initialize the init task struct) and since it needs special cache
* settings, it's the easiest to use this page, the rest of the page is used
* for further pointer tables.
* mmu_get_page_table_entry allocates always a whole page for page tables, this
* means 1024 pages and so 4MB of memory can be mapped. It doesn't make sense
* to manage page tables in smaller pieces as nearly all mappings have that
* size.
*
* ######################################################################
*
*
* ######################################################################
*
* mmu_engage
* ----------
* Thanks to a small helping routine enabling the mmu got quite simple
* and there is only one way left. mmu_engage makes a complete a new mapping
* that only includes the absolute necessary to be able to jump to the final
* position and to restore the original mapping.
* As this code doesn't need a transparent translation register anymore this
* means all registers are free to be used by machines that needs them for
* other purposes.
*
* ######################################################################
*
* mmu_print
* ---------
* This algorithm will print out the page tables of the system as
* appropriate for an 030 or an 040. This is useful for debugging purposes
* and as such is enclosed in #ifdef MMU_PRINT/#endif clauses.
*
* ######################################################################
*
* console_init
* ------------
* The console is also able to be turned off. The console in head.S
* is specifically for debugging and can be very useful. It is surrounded by
* #ifdef / #endif clauses so it doesn't have to ship in known-good
* kernels. It's basic algorithm is to determine the size of the screen
* (in height/width and bit depth) and then use that information for
* displaying an 8x8 font or an 8x16 (widthxheight). I prefer the 8x8 for
* debugging so I can see more good data. But it was trivial to add support
* for both fonts, so I included it.
* Also, the algorithm for plotting pixels is abstracted so that in
* theory other platforms could add support for different kinds of frame
* buffers. This could be very useful.
*
* console_put_penguin
* -------------------
* An important part of any Linux bring up is the penguin and there's
* nothing like getting the Penguin on the screen! This algorithm will work
* on any machine for which there is a console_plot_pixel.
*
* console_scroll
* --------------
* My hope is that the scroll algorithm does the right thing on the
* various platforms, but it wouldn't be hard to add the test conditions
* and new code if it doesn't.
*
* console_putc
* -------------
*
* ######################################################################
*
* Register usage has greatly simplified within head.S. Every subroutine
* saves and restores all registers that it modifies (except it returns a
* value in there of course). So the only register that needs to be initialized
* is the stack pointer.
* All other init code and data is now placed in the init section, so it will
* be automatically freed at the end of the kernel initialization.
*
* ######################################################################
*
* options
* -------
* There are many options available in a build of this file. I've
* taken the time to describe them here to save you the time of searching
* for them and trying to understand what they mean.
*
* CONFIG_xxx: These are the obvious machine configuration defines created
* during configuration. These are defined in autoconf.h.
*
* CONSOLE_DEBUG: Only supports a Mac frame buffer but could easily be
* extended to support other platforms.
*
* TEST_MMU: This is a test harness for running on any given machine but
* getting an MMU dump for another class of machine. The classes of machines
* that can be tested are any of the makes (Atari, Amiga, Mac, VME, etc.)
* and any of the models (030, 040, 060, etc.).
*
* NOTE: TEST_MMU is NOT permanent! It is scheduled to be removed
* When head.S boots on Atari, Amiga, Macintosh, and VME
* machines. At that point the underlying logic will be
* believed to be solid enough to be trusted, and TEST_MMU
* can be dropped. Do note that that will clean up the
* head.S code significantly as large blocks of #if/#else
* clauses can be removed.
*
* MMU_NOCACHE_KERNEL: On the Macintosh platform there was an inquiry into
* determing why devices don't appear to work. A test case was to remove
* the cacheability of the kernel bits.
*
* MMU_PRINT: There is a routine built into head.S that can display the
* MMU data structures. It outputs its result through the serial_putc
* interface. So where ever that winds up driving data, that's where the
* mmu struct will appear.
*
* SERIAL_DEBUG: There are a series of putc() macro statements
* scattered through out the code to give progress of status to the
* person sitting at the console. This constant determines whether those
* are used.
*
* DEBUG: This is the standard DEBUG flag that can be set for building
* the kernel. It has the effect adding additional tests into
* the code.
*
* FONT_6x11:
* FONT_8x8:
* FONT_8x16:
* In theory these could be determined at run time or handed
* over by the booter. But, let's be real, it's a fine hard
* coded value. (But, you will notice the code is run-time
* flexible!) A pointer to the font's struct font_desc
* is kept locally in Lconsole_font. It is used to determine
* font size information dynamically.
*
* Atari constants:
* USE_PRINTER: Use the printer port for serial debug.
* USE_SCC_B: Use the SCC port A (Serial2) for serial debug.
* USE_SCC_A: Use the SCC port B (Modem2) for serial debug.
* USE_MFP: Use the ST-MFP port (Modem1) for serial debug.
*
* Macintosh constants:
* MAC_USE_SCC_A: Use SCC port A (modem) for serial debug.
* MAC_USE_SCC_B: Use SCC port B (printer) for serial debug.
*/
#include <linux/linkage.h>
#include <linux/init.h>
#include <linux/pgtable.h>
#include <asm/bootinfo.h>
#include <asm/bootinfo-amiga.h>
#include <asm/bootinfo-atari.h>
#include <asm/bootinfo-hp300.h>
#include <asm/bootinfo-mac.h>
#include <asm/bootinfo-q40.h>
#include <asm/bootinfo-virt.h>
#include <asm/bootinfo-vme.h>
#include <asm/setup.h>
#include <asm/entry.h>
#include <asm/page.h>
#include <asm/asm-offsets.h>
#ifdef CONFIG_MAC
# include <asm/machw.h>
#endif
#ifdef CONFIG_EARLY_PRINTK
# define SERIAL_DEBUG
# if defined(CONFIG_MAC) && defined(CONFIG_FONT_SUPPORT)
# define CONSOLE_DEBUG
# endif
#endif
#undef MMU_PRINT
#undef MMU_NOCACHE_KERNEL
#undef DEBUG
/*
* For the head.S console, there are three supported fonts, 6x11, 8x16 and 8x8.
* The 8x8 font is harder to read but fits more on the screen.
*/
#define FONT_8x8 /* default */
/* #define FONT_8x16 */ /* 2nd choice */
/* #define FONT_6x11 */ /* 3rd choice */
.globl kernel_pg_dir
.globl availmem
.globl m68k_init_mapped_size
.globl m68k_pgtable_cachemode
.globl m68k_supervisor_cachemode
#ifdef CONFIG_MVME16x
.globl mvme_bdid
#endif
#ifdef CONFIG_Q40
.globl q40_mem_cptr
#endif
CPUTYPE_040 = 1 /* indicates an 040 */
CPUTYPE_060 = 2 /* indicates an 060 */
CPUTYPE_0460 = 3 /* if either above are set, this is set */
CPUTYPE_020 = 4 /* indicates an 020 */
/* Translation control register */
TC_ENABLE = 0x8000
TC_PAGE8K = 0x4000
TC_PAGE4K = 0x0000
/* Transparent translation registers */
TTR_ENABLE = 0x8000 /* enable transparent translation */
TTR_ANYMODE = 0x4000 /* user and kernel mode access */
TTR_KERNELMODE = 0x2000 /* only kernel mode access */
TTR_USERMODE = 0x0000 /* only user mode access */
TTR_CI = 0x0400 /* inhibit cache */
TTR_RW = 0x0200 /* read/write mode */
TTR_RWM = 0x0100 /* read/write mask */
TTR_FCB2 = 0x0040 /* function code base bit 2 */
TTR_FCB1 = 0x0020 /* function code base bit 1 */
TTR_FCB0 = 0x0010 /* function code base bit 0 */
TTR_FCM2 = 0x0004 /* function code mask bit 2 */
TTR_FCM1 = 0x0002 /* function code mask bit 1 */
TTR_FCM0 = 0x0001 /* function code mask bit 0 */
/* Cache Control registers */
CC6_ENABLE_D = 0x80000000 /* enable data cache (680[46]0) */
CC6_FREEZE_D = 0x40000000 /* freeze data cache (68060) */
CC6_ENABLE_SB = 0x20000000 /* enable store buffer (68060) */
CC6_PUSH_DPI = 0x10000000 /* disable CPUSH invalidation (68060) */
CC6_HALF_D = 0x08000000 /* half-cache mode for data cache (68060) */
CC6_ENABLE_B = 0x00800000 /* enable branch cache (68060) */
CC6_CLRA_B = 0x00400000 /* clear all entries in branch cache (68060) */
CC6_CLRU_B = 0x00200000 /* clear user entries in branch cache (68060) */
CC6_ENABLE_I = 0x00008000 /* enable instruction cache (680[46]0) */
CC6_FREEZE_I = 0x00004000 /* freeze instruction cache (68060) */
CC6_HALF_I = 0x00002000 /* half-cache mode for instruction cache (68060) */
CC3_ALLOC_WRITE = 0x00002000 /* write allocate mode(68030) */
CC3_ENABLE_DB = 0x00001000 /* enable data burst (68030) */
CC3_CLR_D = 0x00000800 /* clear data cache (68030) */
CC3_CLRE_D = 0x00000400 /* clear entry in data cache (68030) */
CC3_FREEZE_D = 0x00000200 /* freeze data cache (68030) */
CC3_ENABLE_D = 0x00000100 /* enable data cache (68030) */
CC3_ENABLE_IB = 0x00000010 /* enable instruction burst (68030) */
CC3_CLR_I = 0x00000008 /* clear instruction cache (68030) */
CC3_CLRE_I = 0x00000004 /* clear entry in instruction cache (68030) */
CC3_FREEZE_I = 0x00000002 /* freeze instruction cache (68030) */
CC3_ENABLE_I = 0x00000001 /* enable instruction cache (68030) */
/* Miscellaneous definitions */
PAGESIZE = 4096
PAGESHIFT = 12
ROOT_TABLE_SIZE = 128
PTR_TABLE_SIZE = 128
PAGE_TABLE_SIZE = 64
ROOT_INDEX_SHIFT = 25
PTR_INDEX_SHIFT = 18
PAGE_INDEX_SHIFT = 12
#ifdef DEBUG
/* When debugging use readable names for labels */
#ifdef __STDC__
#define L(name) .head.S.##name
#else
#define L(name) .head.S./**/name
#endif
#else
#ifdef __STDC__
#define L(name) .L##name
#else
#define L(name) .L/**/name
#endif
#endif
/* The __INITDATA stuff is a no-op when ftrace or kgdb are turned on */
#ifndef __INITDATA
#define __INITDATA .data
#define __FINIT .previous
#endif
/* Several macros to make the writing of subroutines easier:
* - func_start marks the beginning of the routine which setups the frame
* register and saves the registers, it also defines another macro
* to automatically restore the registers again.
* - func_return marks the end of the routine and simply calls the prepared
* macro to restore registers and jump back to the caller.
* - func_define generates another macro to automatically put arguments
* onto the stack call the subroutine and cleanup the stack again.
*/
/* Within subroutines these macros can be used to access the arguments
* on the stack. With STACK some allocated memory on the stack can be
* accessed and ARG0 points to the return address (used by mmu_engage).
*/
#define STACK %a6@(stackstart)
#define ARG0 %a6@(4)
#define ARG1 %a6@(8)
#define ARG2 %a6@(12)
#define ARG3 %a6@(16)
#define ARG4 %a6@(20)
.macro func_start name,saveregs,stack=0
L(\name):
linkw %a6,#-\stack
moveml \saveregs,%sp@-
.set stackstart,-\stack
.macro func_return_\name
moveml %sp@+,\saveregs
unlk %a6
rts
.endm
.endm
.macro func_return name
func_return_\name
.endm
.macro func_call name
jbsr L(\name)
.endm
.macro move_stack nr,arg1,arg2,arg3,arg4
.if \nr
move_stack "(\nr-1)",\arg2,\arg3,\arg4
movel \arg1,%sp@-
.endif
.endm
.macro func_define name,nr=0
.macro \name arg1,arg2,arg3,arg4
move_stack \nr,\arg1,\arg2,\arg3,\arg4
func_call \name
.if \nr
lea %sp@(\nr*4),%sp
.endif
.endm
.endm
func_define mmu_map,4
func_define mmu_map_tt,4
func_define mmu_fixup_page_mmu_cache,1
func_define mmu_temp_map,2
func_define mmu_engage
func_define mmu_get_root_table_entry,1
func_define mmu_get_ptr_table_entry,2
func_define mmu_get_page_table_entry,2
func_define mmu_print
func_define get_new_page
#if defined(CONFIG_HP300) || defined(CONFIG_APOLLO)
func_define set_leds
#endif
.macro mmu_map_eq arg1,arg2,arg3
mmu_map \arg1,\arg1,\arg2,\arg3
.endm
.macro get_bi_record record
pea \record
func_call get_bi_record
addql #4,%sp
.endm
func_define serial_putc,1
func_define console_putc,1
func_define console_init
func_define console_put_penguin
func_define console_plot_pixel,3
func_define console_scroll
.macro putc ch
#if defined(CONSOLE_DEBUG) || defined(SERIAL_DEBUG)
pea \ch
#endif
#ifdef CONSOLE_DEBUG
func_call console_putc
#endif
#ifdef SERIAL_DEBUG
func_call serial_putc
#endif
#if defined(CONSOLE_DEBUG) || defined(SERIAL_DEBUG)
addql #4,%sp
#endif
.endm
.macro dputc ch
#ifdef DEBUG
putc \ch
#endif
.endm
func_define putn,1
.macro dputn nr
#ifdef DEBUG
putn \nr
#endif
.endm
.macro puts string
#if defined(CONSOLE_DEBUG) || defined(SERIAL_DEBUG)
__INITDATA
.Lstr\@:
.string "\string"
__FINIT
pea %pc@(.Lstr\@)
func_call puts
addql #4,%sp
#endif
.endm
.macro dputs string
#ifdef DEBUG
puts "\string"
#endif
.endm
#define is_not_amiga(lab) cmpl &MACH_AMIGA,%pc@(m68k_machtype); jne lab
#define is_not_atari(lab) cmpl &MACH_ATARI,%pc@(m68k_machtype); jne lab
#define is_not_mac(lab) cmpl &MACH_MAC,%pc@(m68k_machtype); jne lab
#define is_not_mvme147(lab) cmpl &MACH_MVME147,%pc@(m68k_machtype); jne lab
#define is_not_mvme16x(lab) cmpl &MACH_MVME16x,%pc@(m68k_machtype); jne lab
#define is_not_bvme6000(lab) cmpl &MACH_BVME6000,%pc@(m68k_machtype); jne lab
#define is_mvme147(lab) cmpl &MACH_MVME147,%pc@(m68k_machtype); jeq lab
#define is_mvme16x(lab) cmpl &MACH_MVME16x,%pc@(m68k_machtype); jeq lab
#define is_bvme6000(lab) cmpl &MACH_BVME6000,%pc@(m68k_machtype); jeq lab
#define is_not_hp300(lab) cmpl &MACH_HP300,%pc@(m68k_machtype); jne lab
#define is_not_apollo(lab) cmpl &MACH_APOLLO,%pc@(m68k_machtype); jne lab
#define is_not_q40(lab) cmpl &MACH_Q40,%pc@(m68k_machtype); jne lab
#define is_not_sun3x(lab) cmpl &MACH_SUN3X,%pc@(m68k_machtype); jne lab
#define is_not_virt(lab) cmpl &MACH_VIRT,%pc@(m68k_machtype); jne lab
#define hasnt_leds(lab) cmpl &MACH_HP300,%pc@(m68k_machtype); \
jeq 42f; \
cmpl &MACH_APOLLO,%pc@(m68k_machtype); \
jne lab ;\
42:\
#define is_040_or_060(lab) btst &CPUTYPE_0460,%pc@(L(cputype)+3); jne lab
#define is_not_040_or_060(lab) btst &CPUTYPE_0460,%pc@(L(cputype)+3); jeq lab
#define is_040(lab) btst &CPUTYPE_040,%pc@(L(cputype)+3); jne lab
#define is_060(lab) btst &CPUTYPE_060,%pc@(L(cputype)+3); jne lab
#define is_not_060(lab) btst &CPUTYPE_060,%pc@(L(cputype)+3); jeq lab
#define is_020(lab) btst &CPUTYPE_020,%pc@(L(cputype)+3); jne lab
#define is_not_020(lab) btst &CPUTYPE_020,%pc@(L(cputype)+3); jeq lab
/* On the HP300 we use the on-board LEDs for debug output before
the console is running. Writing a 1 bit turns the corresponding LED
_off_ - on the 340 bit 7 is towards the back panel of the machine. */
.macro leds mask
#if defined(CONFIG_HP300) || defined(CONFIG_APOLLO)
hasnt_leds(.Lled\@)
pea \mask
func_call set_leds
addql #4,%sp
.Lled\@:
#endif
.endm
__HEAD
ENTRY(_stext)
/*
* Version numbers of the bootinfo interface
* The area from _stext to _start will later be used as kernel pointer table
*/
bras 1f /* Jump over bootinfo version numbers */
.long BOOTINFOV_MAGIC
.long MACH_AMIGA, AMIGA_BOOTI_VERSION
.long MACH_ATARI, ATARI_BOOTI_VERSION
.long MACH_MVME147, MVME147_BOOTI_VERSION
.long MACH_MVME16x, MVME16x_BOOTI_VERSION
.long MACH_BVME6000, BVME6000_BOOTI_VERSION
.long MACH_MAC, MAC_BOOTI_VERSION
.long MACH_Q40, Q40_BOOTI_VERSION
.long MACH_HP300, HP300_BOOTI_VERSION
.long 0
1: jra __start
.equ kernel_pg_dir,_stext
.equ .,_stext+PAGESIZE
ENTRY(_start)
jra __start
__INIT
ENTRY(__start)
/*
* Setup initial stack pointer
*/
lea %pc@(_stext),%sp
/*
* Record the CPU and machine type.
*/
get_bi_record BI_MACHTYPE
lea %pc@(m68k_machtype),%a1
movel %a0@,%a1@
get_bi_record BI_FPUTYPE
lea %pc@(m68k_fputype),%a1
movel %a0@,%a1@
get_bi_record BI_MMUTYPE
lea %pc@(m68k_mmutype),%a1
movel %a0@,%a1@
get_bi_record BI_CPUTYPE
lea %pc@(m68k_cputype),%a1
movel %a0@,%a1@
leds 0x1
#ifdef CONFIG_MAC
/*
* For Macintosh, we need to determine the display parameters early (at least
* while debugging it).
*/
is_not_mac(L(test_notmac))
get_bi_record BI_MAC_VADDR
lea %pc@(L(mac_videobase)),%a1
movel %a0@,%a1@
get_bi_record BI_MAC_VDEPTH
lea %pc@(L(mac_videodepth)),%a1
movel %a0@,%a1@
get_bi_record BI_MAC_VDIM
lea %pc@(L(mac_dimensions)),%a1
movel %a0@,%a1@
get_bi_record BI_MAC_VROW
lea %pc@(L(mac_rowbytes)),%a1
movel %a0@,%a1@
get_bi_record BI_MAC_SCCBASE
lea %pc@(L(mac_sccbase)),%a1
movel %a0@,%a1@
L(test_notmac):
#endif /* CONFIG_MAC */
#ifdef CONFIG_VIRT
is_not_virt(L(test_notvirt))
get_bi_record BI_VIRT_GF_TTY_BASE
lea %pc@(L(virt_gf_tty_base)),%a1
movel %a0@,%a1@
L(test_notvirt):
#endif /* CONFIG_VIRT */
/*
* There are ultimately two pieces of information we want for all kinds of
* processors CpuType and CacheBits. The CPUTYPE was passed in from booter
* and is converted here from a booter type definition to a separate bit
* number which allows for the standard is_0x0 macro tests.
*/
movel %pc@(m68k_cputype),%d0
/*
* Assume it's an 030
*/
clrl %d1
/*
* Test the BootInfo cputype for 060
*/
btst #CPUB_68060,%d0
jeq 1f
bset #CPUTYPE_060,%d1
bset #CPUTYPE_0460,%d1
jra 3f
1:
/*
* Test the BootInfo cputype for 040
*/
btst #CPUB_68040,%d0
jeq 2f
bset #CPUTYPE_040,%d1
bset #CPUTYPE_0460,%d1
jra 3f
2:
/*
* Test the BootInfo cputype for 020
*/
btst #CPUB_68020,%d0
jeq 3f
bset #CPUTYPE_020,%d1
jra 3f
3:
/*
* Record the cpu type
*/
lea %pc@(L(cputype)),%a0
movel %d1,%a0@
/*
* NOTE:
*
* Now the macros are valid:
* is_040_or_060
* is_not_040_or_060
* is_040
* is_060
* is_not_060
*/
/*
* Determine the cache mode for pages holding MMU tables
* and for supervisor mode, unused for '020 and '030
*/
clrl %d0
clrl %d1
is_not_040_or_060(L(save_cachetype))
/*
* '040 or '060
* d1 := cacheable write-through
* NOTE: The 68040 manual strongly recommends non-cached for MMU tables,
* but we have been using write-through since at least 2.0.29 so I
* guess it is OK.
*/
#ifdef CONFIG_060_WRITETHROUGH
/*
* If this is a 68060 board using drivers with cache coherency
* problems, then supervisor memory accesses need to be write-through
* also; otherwise, we want copyback.
*/
is_not_060(1f)
movel #_PAGE_CACHE040W,%d0
jra L(save_cachetype)
#endif /* CONFIG_060_WRITETHROUGH */
1:
movew #_PAGE_CACHE040,%d0
movel #_PAGE_CACHE040W,%d1
L(save_cachetype):
/* Save cache mode for supervisor mode and page tables
*/
lea %pc@(m68k_supervisor_cachemode),%a0
movel %d0,%a0@
lea %pc@(m68k_pgtable_cachemode),%a0
movel %d1,%a0@
/*
* raise interrupt level
*/
movew #0x2700,%sr
/*
If running on an Atari, determine the I/O base of the
serial port and test if we are running on a Medusa or Hades.
This test is necessary here, because on the Hades the serial
port is only accessible in the high I/O memory area.
The test whether it is a Medusa is done by writing to the byte at
phys. 0x0. This should result in a bus error on all other machines.
...should, but doesn't. The Afterburner040 for the Falcon has the
same behaviour (0x0..0x7 are no ROM shadow). So we have to do
another test to distinguish Medusa and AB040. This is a
read attempt for 0x00ff82fe phys. that should bus error on a Falcon
(+AB040), but is in the range where the Medusa always asserts DTACK.
The test for the Hades is done by reading address 0xb0000000. This
should give a bus error on the Medusa.
*/
#ifdef CONFIG_ATARI
is_not_atari(L(notypetest))
/* get special machine type (Medusa/Hades/AB40) */
moveq #0,%d3 /* default if tag doesn't exist */
get_bi_record BI_ATARI_MCH_TYPE
tstl %d0
jbmi 1f
movel %a0@,%d3
lea %pc@(atari_mch_type),%a0
movel %d3,%a0@
1:
/* On the Hades, the iobase must be set up before opening the
* serial port. There are no I/O regs at 0x00ffxxxx at all. */
moveq #0,%d0
cmpl #ATARI_MACH_HADES,%d3
jbne 1f
movel #0xff000000,%d0 /* Hades I/O base addr: 0xff000000 */
1: lea %pc@(L(iobase)),%a0
movel %d0,%a0@
L(notypetest):
#endif
#ifdef CONFIG_VME
is_mvme147(L(getvmetype))
is_bvme6000(L(getvmetype))
is_not_mvme16x(L(gvtdone))
/* See if the loader has specified the BI_VME_TYPE tag. Recent
* versions of VMELILO and TFTPLILO do this. We have to do this
* early so we know how to handle console output. If the tag
* doesn't exist then we use the Bug for output on MVME16x.
*/
L(getvmetype):
get_bi_record BI_VME_TYPE
tstl %d0
jbmi 1f
movel %a0@,%d3
lea %pc@(vme_brdtype),%a0
movel %d3,%a0@
1:
#ifdef CONFIG_MVME16x
is_not_mvme16x(L(gvtdone))
/* Need to get the BRD_ID info to differentiate between 162, 167,
* etc. This is available as a BI_VME_BRDINFO tag with later
* versions of VMELILO and TFTPLILO, otherwise we call the Bug.
*/
get_bi_record BI_VME_BRDINFO
tstl %d0
jpl 1f
/* Get pointer to board ID data from Bug */
movel %d2,%sp@-
trap #15
.word 0x70 /* trap 0x70 - .BRD_ID */
movel %sp@+,%a0
1:
lea %pc@(mvme_bdid),%a1
/* Structure is 32 bytes long */
movel %a0@+,%a1@+
movel %a0@+,%a1@+
movel %a0@+,%a1@+
movel %a0@+,%a1@+
movel %a0@+,%a1@+
movel %a0@+,%a1@+
movel %a0@+,%a1@+
movel %a0@+,%a1@+
#endif
L(gvtdone):
#endif
#ifdef CONFIG_HP300
is_not_hp300(L(nothp))
/* Get the address of the UART for serial debugging */
get_bi_record BI_HP300_UART_ADDR
tstl %d0
jbmi 1f
movel %a0@,%d3
lea %pc@(L(uartbase)),%a0
movel %d3,%a0@
get_bi_record BI_HP300_UART_SCODE
tstl %d0
jbmi 1f
movel %a0@,%d3
lea %pc@(L(uart_scode)),%a0
movel %d3,%a0@
1:
L(nothp):
#endif
/*
* Initialize serial port
*/
jbsr L(serial_init)
/*
* Initialize console
*/
#ifdef CONFIG_MAC
is_not_mac(L(nocon))
# ifdef CONSOLE_DEBUG
console_init
# ifdef CONFIG_LOGO
console_put_penguin
# endif /* CONFIG_LOGO */
# endif /* CONSOLE_DEBUG */
L(nocon):
#endif /* CONFIG_MAC */
putc '\n'
putc 'A'
leds 0x2
dputn %pc@(L(cputype))
dputn %pc@(m68k_supervisor_cachemode)
dputn %pc@(m68k_pgtable_cachemode)
dputc '\n'
/*
* Save physical start address of kernel
*/
lea %pc@(L(phys_kernel_start)),%a0
lea %pc@(_stext),%a1
subl #_stext,%a1
addl #PAGE_OFFSET,%a1
movel %a1,%a0@
putc 'B'
leds 0x4
/*
* mmu_init
*
* This block of code does what's necessary to map in the various kinds
* of machines for execution of Linux.
* First map the first 4, 8, or 16 MB of kernel code & data
*/
get_bi_record BI_MEMCHUNK
movel %a0@(4),%d0
movel #16*1024*1024,%d1
cmpl %d0,%d1
jls 1f
lsrl #1,%d1
cmpl %d0,%d1
jls 1f
lsrl #1,%d1
1:
lea %pc@(m68k_init_mapped_size),%a0
movel %d1,%a0@
mmu_map #PAGE_OFFSET,%pc@(L(phys_kernel_start)),%d1,\
%pc@(m68k_supervisor_cachemode)
putc 'C'
#ifdef CONFIG_AMIGA
L(mmu_init_amiga):
is_not_amiga(L(mmu_init_not_amiga))
/*
* mmu_init_amiga
*/
putc 'D'
is_not_040_or_060(1f)
/*
* 040: Map the 16Meg range physical 0x0 up to logical 0x8000.0000
*/
mmu_map #0x80000000,#0,#0x01000000,#_PAGE_NOCACHE_S
/*
* Map the Zorro III I/O space with transparent translation
* for frame buffer memory etc.
*/
mmu_map_tt #1,#0x40000000,#0x20000000,#_PAGE_NOCACHE_S
jbra L(mmu_init_done)
1:
/*
* 030: Map the 32Meg range physical 0x0 up to logical 0x8000.0000
*/
mmu_map #0x80000000,#0,#0x02000000,#_PAGE_NOCACHE030
mmu_map_tt #1,#0x40000000,#0x20000000,#_PAGE_NOCACHE030
jbra L(mmu_init_done)
L(mmu_init_not_amiga):
#endif
#ifdef CONFIG_ATARI
L(mmu_init_atari):
is_not_atari(L(mmu_init_not_atari))
putc 'E'
/* On the Atari, we map the I/O region (phys. 0x00ffxxxx) by mapping
the last 16 MB of virtual address space to the first 16 MB (i.e.
0xffxxxxxx -> 0x00xxxxxx). For this, an additional pointer table is
needed. I/O ranges are marked non-cachable.
For the Medusa it is better to map the I/O region transparently
(i.e. 0xffxxxxxx -> 0xffxxxxxx), because some I/O registers are
accessible only in the high area.
On the Hades all I/O registers are only accessible in the high
area.
*/
/* I/O base addr for non-Medusa, non-Hades: 0x00000000 */
moveq #0,%d0
movel %pc@(atari_mch_type),%d3
cmpl #ATARI_MACH_MEDUSA,%d3
jbeq 2f
cmpl #ATARI_MACH_HADES,%d3