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metag: Boot

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Add boot code for metag. Due to the multi-threaded nature of Meta it is
not uncommon for an RTOS or bare metal application to be started on
other hardware threads by the bootloader. Since there is a single MMU
switch which affects all threads, the MMU is traditionally configured by
the bootloader prior to starting Linux. The bootloader passes a
structure to Linux which among other things contains information about
memory regions which have been mapped. Linux then assumes control of the
local heap memory region.

A kernel arguments string pointer or a flattened device tree pointer can
be provided in the third argument.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
This commit is contained in:
James Hogan 2012-09-21 17:38:15 +01:00
parent 87aa1328f2
commit 85d9d7a920
6 changed files with 715 additions and 0 deletions
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4
arch/metag/boot/.gitignore vendored Normal file
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vmlinux*
uImage*
ramdisk.*
*.dtb

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/*
* arch/metag/include/asm/mach/arch.h
*
* Copyright (C) 2012 Imagination Technologies Ltd.
*
* based on the ARM version:
* Copyright (C) 2000 Russell King
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifndef _METAG_MACH_ARCH_H_
#define _METAG_MACH_ARCH_H_
#include <linux/stddef.h>
/**
* struct machine_desc - Describes a board controlled by a Meta.
* @name: Board/SoC name.
* @dt_compat: Array of device tree 'compatible' strings.
*
* @nr_irqs: Maximum number of IRQs.
* If 0, defaults to NR_IRQS in asm-generic/irq.h.
*
* @init_early: Early init callback.
* @init_irq: IRQ init callback for setting up IRQ controllers.
* @init_machine: Arch init callback for setting up devices.
* @init_late: Late init callback.
*
* This structure is provided by each board which can be controlled by a Meta.
* It is chosen by matching the compatible strings in the device tree provided
* by the bootloader with the strings in @dt_compat, and sets up any aspects of
* the machine that aren't configured with device tree (yet).
*/
struct machine_desc {
const char *name;
const char **dt_compat;
unsigned int nr_irqs;
void (*init_early)(void);
void (*init_irq)(void);
void (*init_machine)(void);
void (*init_late)(void);
};
/*
* Current machine - only accessible during boot.
*/
extern struct machine_desc *machine_desc;
/*
* Machine type table - also only accessible during boot
*/
extern struct machine_desc __arch_info_begin[], __arch_info_end[];
#define for_each_machine_desc(p) \
for (p = __arch_info_begin; p < __arch_info_end; p++)
static inline struct machine_desc *default_machine_desc(void)
{
/* the default machine is the last one linked in */
if (__arch_info_end - 1 < __arch_info_begin)
return NULL;
return __arch_info_end - 1;
}
/*
* Set of macros to define architecture features. This is built into
* a table by the linker.
*/
#define MACHINE_START(_type, _name) \
static const struct machine_desc __mach_desc_##_type \
__used \
__attribute__((__section__(".arch.info.init"))) = { \
.name = _name,
#define MACHINE_END \
};
#endif /* _METAG_MACH_ARCH_H_ */

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#ifndef _ASM_METAG_SETUP_H
#define _ASM_METAG_SETUP_H
#include <uapi/asm/setup.h>
void per_cpu_trap_init(unsigned long);
extern void __init dump_machine_table(void);
#endif /* _ASM_METAG_SETUP_H */

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! Copyright 2005,2006,2007,2009 Imagination Technologies
#include <linux/init.h>
#include <generated/asm-offsets.h>
#undef __exit
__HEAD
! Setup the stack and get going into _metag_start_kernel
.global __start
.type __start,function
__start:
! D1Ar1 contains pTBI (ISTAT)
! D0Ar2 contains pTBI
! D1Ar3 contains __pTBISegs
! D0Ar4 contains kernel arglist pointer
MOVT D0Re0,#HI(___pTBIs)
ADD D0Re0,D0Re0,#LO(___pTBIs)
SETL [D0Re0],D0Ar2,D1Ar1
MOVT D0Re0,#HI(___pTBISegs)
ADD D0Re0,D0Re0,#LO(___pTBISegs)
SETD [D0Re0],D1Ar3
MOV A0FrP,#0
MOV D0Re0,#0
MOV D1Re0,#0
MOV D1Ar3,#0
MOV D1Ar1,D0Ar4 !Store kernel boot params
MOV D1Ar5,#0
MOV D0Ar6,#0
#ifdef CONFIG_METAG_DSP
MOV D0.8,#0
#endif
MOVT A0StP,#HI(_init_thread_union)
ADD A0StP,A0StP,#LO(_init_thread_union)
ADD A0StP,A0StP,#THREAD_INFO_SIZE
MOVT D1RtP,#HI(_metag_start_kernel)
CALL D1RtP,#LO(_metag_start_kernel)
.size __start,.-__start
!! Needed by TBX
.global __exit
.type __exit,function
__exit:
XOR TXENABLE,D0Re0,D0Re0
.size __exit,.-__exit

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/*
* arch/metag/kernel/machines.c
*
* Copyright (C) 2012 Imagination Technologies Ltd.
*
* Generic Meta Boards.
*/
#include <linux/init.h>
#include <asm/irq.h>
#include <asm/mach/arch.h>
static const char *meta_boards_compat[] __initdata = {
"img,meta",
NULL,
};
MACHINE_START(META, "Generic Meta")
.dt_compat = meta_boards_compat,
MACHINE_END

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/*
* Copyright (C) 2005-2012 Imagination Technologies Ltd.
*
* This file contains the architecture-dependant parts of system setup.
*
*/
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/sched.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/fs.h>
#include <linux/console.h>
#include <linux/genhd.h>
#include <linux/errno.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/root_dev.h>
#include <linux/initrd.h>
#include <linux/seq_file.h>
#include <linux/pfn.h>
#include <linux/start_kernel.h>
#include <linux/cpu.h>
#include <linux/memblock.h>
#include <linux/of_fdt.h>
#include <asm/cachepart.h>
#include <asm/clock.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/processor.h>
#include <asm/traps.h>
#include <asm/mmu.h>
#include <asm/cpu.h>
#include <asm/hwthread.h>
#include <asm/mmzone.h>
#include <asm/l2cache.h>
#include <asm/prom.h>
#include <asm/mach/arch.h>
#include <asm/core_reg.h>
#include <asm/highmem.h>
/* PRIV protect as many registers as possible. */
#define DEFAULT_PRIV 0xff0f7f00
/* Enable unaligned access checking. */
#define UNALIGNED_PRIV 0x00000010
#ifdef CONFIG_METAG_UNALIGNED
#define PRIV_BITS (DEFAULT_PRIV | UNALIGNED_PRIV)
#else
#define PRIV_BITS DEFAULT_PRIV
#endif
extern char _heap_start[];
#ifdef CONFIG_METAG_BUILTIN_DTB
extern u32 __dtb_start[];
#endif
struct machine_desc *machine_desc __initdata;
/*
* Map a Linux CPU number to a hardware thread ID
* In SMP this will be setup with the correct mapping at startup; in UP this
* will map to the HW thread on which we are running.
*/
u8 cpu_2_hwthread_id[NR_CPUS] __read_mostly = {
[0 ... NR_CPUS-1] = BAD_HWTHREAD_ID
};
/*
* Map a hardware thread ID to a Linux CPU number
* In SMP this will be fleshed out with the correct CPU ID for a particular
* hardware thread. In UP this will be initialised with the boot CPU ID.
*/
u8 hwthread_id_2_cpu[4] __read_mostly = {
[0 ... 3] = BAD_CPU_ID
};
/* The relative offset of the MMU mapped memory (from ldlk or bootloader)
* to the real physical memory. This is needed as we have to use the
* physical addresses in the MMU tables (pte entries), and not the virtual
* addresses.
* This variable is used in the __pa() and __va() macros, and should
* probably only be used via them.
*/
unsigned int meta_memoffset;
static char __initdata *original_cmd_line;
DEFINE_PER_CPU(PTBI, pTBI);
/*
* Mapping are specified as "CPU_ID:HWTHREAD_ID", e.g.
*
* "hwthread_map=0:1,1:2,2:3,3:0"
*
* Linux CPU ID HWTHREAD_ID
* ---------------------------
* 0 1
* 1 2
* 2 3
* 3 0
*/
static int __init parse_hwthread_map(char *p)
{
int cpu;
while (*p) {
cpu = (*p++) - '0';
if (cpu < 0 || cpu > 9)
goto err_cpu;
p++; /* skip semi-colon */
cpu_2_hwthread_id[cpu] = (*p++) - '0';
if (cpu_2_hwthread_id[cpu] >= 4)
goto err_thread;
hwthread_id_2_cpu[cpu_2_hwthread_id[cpu]] = cpu;
if (*p == ',')
p++; /* skip comma */
}
return 0;
err_cpu:
pr_err("%s: hwthread_map cpu argument out of range\n", __func__);
return -EINVAL;
err_thread:
pr_err("%s: hwthread_map thread argument out of range\n", __func__);
return -EINVAL;
}
early_param("hwthread_map", parse_hwthread_map);
void __init dump_machine_table(void)
{
struct machine_desc *p;
const char **compat;
pr_info("Available machine support:\n\tNAME\t\tCOMPATIBLE LIST\n");
for_each_machine_desc(p) {
pr_info("\t%s\t[", p->name);
for (compat = p->dt_compat; compat && *compat; ++compat)
printk(" '%s'", *compat);
printk(" ]\n");
}
pr_info("\nPlease check your kernel config and/or bootloader.\n");
hard_processor_halt(HALT_PANIC);
}
#ifdef CONFIG_METAG_HALT_ON_PANIC
static int metag_panic_event(struct notifier_block *this, unsigned long event,
void *ptr)
{
hard_processor_halt(HALT_PANIC);
return NOTIFY_DONE;
}
static struct notifier_block metag_panic_block = {
metag_panic_event,
NULL,
0
};
#endif
void __init setup_arch(char **cmdline_p)
{
unsigned long start_pfn;
unsigned long text_start = (unsigned long)(&_stext);
unsigned long cpu = smp_processor_id();
unsigned long heap_start, heap_end;
unsigned long start_pte;
PTBI _pTBI;
PTBISEG p_heap;
int heap_id, i;
metag_cache_probe();
/* try interpreting the argument as a device tree */
machine_desc = setup_machine_fdt(original_cmd_line);
/* if it doesn't look like a device tree it must be a command line */
if (!machine_desc) {
#ifdef CONFIG_METAG_BUILTIN_DTB
/* try the embedded device tree */
machine_desc = setup_machine_fdt(__dtb_start);
if (!machine_desc)
panic("Invalid embedded device tree.");
#else
/* use the default machine description */
machine_desc = default_machine_desc();
#endif
#ifndef CONFIG_CMDLINE_FORCE
/* append the bootloader cmdline to any builtin fdt cmdline */
if (boot_command_line[0] && original_cmd_line[0])
strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
strlcat(boot_command_line, original_cmd_line,
COMMAND_LINE_SIZE);
#endif
}
setup_meta_clocks(machine_desc->clocks);
*cmdline_p = boot_command_line;
parse_early_param();
/*
* Make sure we don't alias in dcache or icache
*/
check_for_cache_aliasing(cpu);
#ifdef CONFIG_METAG_HALT_ON_PANIC
atomic_notifier_chain_register(&panic_notifier_list,
&metag_panic_block);
#endif
#ifdef CONFIG_DUMMY_CONSOLE
conswitchp = &dummy_con;
#endif
if (!(__core_reg_get(TXSTATUS) & TXSTATUS_PSTAT_BIT))
panic("Privilege must be enabled for this thread.");
_pTBI = __TBI(TBID_ISTAT_BIT);
per_cpu(pTBI, cpu) = _pTBI;
if (!per_cpu(pTBI, cpu))
panic("No TBI found!");
/*
* Initialize all interrupt vectors to our copy of __TBIUnExpXXX,
* rather than the version from the bootloader. This makes call
* stacks easier to understand and may allow us to unmap the
* bootloader at some point.
*
* We need to keep the LWK handler that TBI installed in order to
* be able to do inter-thread comms.
*/
for (i = 0; i <= TBID_SIGNUM_MAX; i++)
if (i != TBID_SIGNUM_LWK)
_pTBI->fnSigs[i] = __TBIUnExpXXX;
/* A Meta requirement is that the kernel is loaded (virtually)
* at the PAGE_OFFSET.
*/
if (PAGE_OFFSET != text_start)
panic("Kernel not loaded at PAGE_OFFSET (%#x) but at %#lx.",
PAGE_OFFSET, text_start);
start_pte = mmu_read_second_level_page(text_start);
/*
* Kernel pages should have the PRIV bit set by the bootloader.
*/
if (!(start_pte & _PAGE_KERNEL))
panic("kernel pte does not have PRIV set");
/*
* See __pa and __va in include/asm/page.h.
* This value is negative when running in local space but the
* calculations work anyway.
*/
meta_memoffset = text_start - (start_pte & PAGE_MASK);
/* Now lets look at the heap space */
heap_id = (__TBIThreadId() & TBID_THREAD_BITS)
+ TBID_SEG(0, TBID_SEGSCOPE_LOCAL, TBID_SEGTYPE_HEAP);
p_heap = __TBIFindSeg(NULL, heap_id);
if (!p_heap)
panic("Could not find heap from TBI!");
/* The heap begins at the first full page after the kernel data. */
heap_start = (unsigned long) &_heap_start;
/* The heap ends at the end of the heap segment specified with
* ldlk.
*/
if (is_global_space(text_start)) {
pr_debug("WARNING: running in global space!\n");
heap_end = (unsigned long)p_heap->pGAddr + p_heap->Bytes;
} else {
heap_end = (unsigned long)p_heap->pLAddr + p_heap->Bytes;
}
ROOT_DEV = Root_RAM0;
/* init_mm is the mm struct used for the first task. It is then
* cloned for all other tasks spawned from that task.
*
* Note - we are using the virtual addresses here.
*/
init_mm.start_code = (unsigned long)(&_stext);
init_mm.end_code = (unsigned long)(&_etext);
init_mm.end_data = (unsigned long)(&_edata);
init_mm.brk = (unsigned long)heap_start;
min_low_pfn = PFN_UP(__pa(text_start));
max_low_pfn = PFN_DOWN(__pa(heap_end));
pfn_base = min_low_pfn;
/* Round max_pfn up to a 4Mb boundary. The free_bootmem_node()
* call later makes sure to keep the rounded up pages marked reserved.
*/
max_pfn = max_low_pfn + ((1 << MAX_ORDER) - 1);
max_pfn &= ~((1 << MAX_ORDER) - 1);
start_pfn = PFN_UP(__pa(heap_start));
if (min_low_pfn & ((1 << MAX_ORDER) - 1)) {
/* Theoretically, we could expand the space that the
* bootmem allocator covers - much as we do for the
* 'high' address, and then tell the bootmem system
* that the lowest chunk is 'not available'. Right
* now it is just much easier to constrain the
* user to always MAX_ORDER align their kernel space.
*/
panic("Kernel must be %d byte aligned, currently at %#lx.",
1 << (MAX_ORDER + PAGE_SHIFT),
min_low_pfn << PAGE_SHIFT);
}
#ifdef CONFIG_HIGHMEM
highstart_pfn = highend_pfn = max_pfn;
high_memory = (void *) __va(PFN_PHYS(highstart_pfn));
#else
high_memory = (void *)__va(PFN_PHYS(max_pfn));
#endif
paging_init(heap_end);
setup_txprivext();
/* Setup the boot cpu's mapping. The rest will be setup below. */
cpu_2_hwthread_id[smp_processor_id()] = hard_processor_id();
hwthread_id_2_cpu[hard_processor_id()] = smp_processor_id();
unflatten_device_tree();
#ifdef CONFIG_SMP
smp_init_cpus();
#endif
if (machine_desc->init_early)
machine_desc->init_early();
}
static int __init customize_machine(void)
{
/* customizes platform devices, or adds new ones */
if (machine_desc->init_machine)
machine_desc->init_machine();
return 0;
}
arch_initcall(customize_machine);
static int __init init_machine_late(void)
{
if (machine_desc->init_late)
machine_desc->init_late();
return 0;
}
late_initcall(init_machine_late);
#ifdef CONFIG_PROC_FS
/*
* Get CPU information for use by the procfs.
*/
static const char *get_cpu_capabilities(unsigned int txenable)
{
#ifdef CONFIG_METAG_META21
/* See CORE_ID in META HTP.GP TRM - Architecture Overview 2.1.238 */
int coreid = metag_in32(METAC_CORE_ID);
unsigned int dsp_type = (coreid >> 3) & 7;
unsigned int fpu_type = (coreid >> 7) & 3;
switch (dsp_type | fpu_type << 3) {
case (0x00): return "EDSP";
case (0x01): return "DSP";
case (0x08): return "EDSP+LFPU";
case (0x09): return "DSP+LFPU";
case (0x10): return "EDSP+FPU";
case (0x11): return "DSP+FPU";
}
return "UNKNOWN";
#else
if (!(txenable & TXENABLE_CLASS_BITS))
return "DSP";
else
return "";
#endif
}
static int show_cpuinfo(struct seq_file *m, void *v)
{
const char *cpu;
unsigned int txenable, thread_id, major, minor;
unsigned long clockfreq = get_coreclock();
#ifdef CONFIG_SMP
int i;
unsigned long lpj;
#endif
cpu = "META";
txenable = __core_reg_get(TXENABLE);
major = (txenable & TXENABLE_MAJOR_REV_BITS) >> TXENABLE_MAJOR_REV_S;
minor = (txenable & TXENABLE_MINOR_REV_BITS) >> TXENABLE_MINOR_REV_S;
thread_id = (txenable >> 8) & 0x3;
#ifdef CONFIG_SMP
for_each_online_cpu(i) {
lpj = per_cpu(cpu_data, i).loops_per_jiffy;
txenable = core_reg_read(TXUCT_ID, TXENABLE_REGNUM,
cpu_2_hwthread_id[i]);
seq_printf(m, "CPU:\t\t%s %d.%d (thread %d)\n"
"Clocking:\t%lu.%1luMHz\n"
"BogoMips:\t%lu.%02lu\n"
"Calibration:\t%lu loops\n"
"Capabilities:\t%s\n\n",
cpu, major, minor, i,
clockfreq / 1000000, (clockfreq / 100000) % 10,
lpj / (500000 / HZ), (lpj / (5000 / HZ)) % 100,
lpj,
get_cpu_capabilities(txenable));
}
#else
seq_printf(m, "CPU:\t\t%s %d.%d (thread %d)\n"
"Clocking:\t%lu.%1luMHz\n"
"BogoMips:\t%lu.%02lu\n"
"Calibration:\t%lu loops\n"
"Capabilities:\t%s\n",
cpu, major, minor, thread_id,
clockfreq / 1000000, (clockfreq / 100000) % 10,
loops_per_jiffy / (500000 / HZ),
(loops_per_jiffy / (5000 / HZ)) % 100,
loops_per_jiffy,
get_cpu_capabilities(txenable));
#endif /* CONFIG_SMP */
#ifdef CONFIG_METAG_L2C
if (meta_l2c_is_present()) {
seq_printf(m, "L2 cache:\t%s\n"
"L2 cache size:\t%d KB\n",
meta_l2c_is_enabled() ? "enabled" : "disabled",
meta_l2c_size() >> 10);
}
#endif
return 0;
}
static void *c_start(struct seq_file *m, loff_t *pos)
{
return (void *)(*pos == 0);
}
static void *c_next(struct seq_file *m, void *v, loff_t *pos)
{
return NULL;
}
static void c_stop(struct seq_file *m, void *v)
{
}
const struct seq_operations cpuinfo_op = {
.start = c_start,
.next = c_next,
.stop = c_stop,
.show = show_cpuinfo,
};
#endif /* CONFIG_PROC_FS */
void __init metag_start_kernel(char *args)
{
/* Zero the timer register so timestamps are from the point at
* which the kernel started running.
*/
__core_reg_set(TXTIMER, 0);
/* Clear the bss. */
memset(__bss_start, 0,
(unsigned long)__bss_stop - (unsigned long)__bss_start);
/* Remember where these are for use in setup_arch */
original_cmd_line = args;
current_thread_info()->cpu = hard_processor_id();
start_kernel();
}
/*
* Setup TXPRIVEXT register to be prevent userland from touching our
* precious registers.
*/
void setup_txprivext(void)
{
__core_reg_set(TXPRIVEXT, PRIV_BITS);
}
PTBI pTBI_get(unsigned int cpu)
{
return per_cpu(pTBI, cpu);
}
#if defined(CONFIG_METAG_DSP) && defined(CONFIG_METAG_FPU)
char capabilites[] = "dsp fpu";
#elif defined(CONFIG_METAG_DSP)
char capabilites[] = "dsp";
#elif defined(CONFIG_METAG_FPU)
char capabilites[] = "fpu";
#else
char capabilites[] = "";
#endif
static struct ctl_table caps_kern_table[] = {
{
.procname = "capabilities",
.data = capabilites,
.maxlen = sizeof(capabilites),
.mode = 0444,
.proc_handler = proc_dostring,
},
{}
};
static struct ctl_table caps_root_table[] = {
{
.procname = "kernel",
.mode = 0555,
.child = caps_kern_table,
},
{}
};
static int __init capabilities_register_sysctl(void)
{
struct ctl_table_header *caps_table_header;
caps_table_header = register_sysctl_table(caps_root_table);
if (!caps_table_header) {
pr_err("Unable to register CAPABILITIES sysctl\n");
return -ENOMEM;
}
return 0;
}
core_initcall(capabilities_register_sysctl);