arch/xtensa/kernel/setup.c

/*
 * arch/xtensa/kernel/setup.c
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License.  See the file "COPYING" in the main directory of this archive
 * for more details.
 *
 * Copyright (C) 1995  Linus Torvalds
 * Copyright (C) 2001 - 2005  Tensilica Inc.
 * Copyright (C) 2014 - 2016  Cadence Design Systems Inc.
 *
 * Chris Zankel	<chris@zankel.net>
 * Joe Taylor	<joe@tensilica.com, joetylr@yahoo.com>
 * Kevin Chea
 * Marc Gauthier<marc@tensilica.com> <marc@alumni.uwaterloo.ca>
 */

#include <linux/errno.h>
#include <linux/init.h>
#include <linux/mm.h>
#include <linux/proc_fs.h>
#include <linux/screen_info.h>
#include <linux/kernel.h>
#include <linux/percpu.h>
#include <linux/reboot.h>
#include <linux/cpu.h>
#include <linux/of.h>
#include <linux/of_fdt.h>

#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
# include <linux/console.h>
#endif

#ifdef CONFIG_PROC_FS
# include <linux/seq_file.h>
#endif

#include <asm/bootparam.h>
#include <asm/kasan.h>
#include <asm/mmu_context.h>
#include <asm/page.h>
#include <asm/param.h>
#include <asm/platform.h>
#include <asm/processor.h>
#include <asm/sections.h>
#include <asm/setup.h>
#include <asm/smp.h>
#include <asm/sysmem.h>
#include <asm/timex.h>
#include <asm/traps.h>

#if defined(CONFIG_VGA_CONSOLE) || defined(CONFIG_DUMMY_CONSOLE)
struct screen_info screen_info = {
	.orig_x = 0,
	.orig_y = 24,
	.orig_video_cols = 80,
	.orig_video_lines = 24,
	.orig_video_isVGA = 1,
	.orig_video_points = 16,
};
#endif

#ifdef CONFIG_BLK_DEV_INITRD
extern unsigned long initrd_start;
extern unsigned long initrd_end;
extern int initrd_below_start_ok;
#endif

#ifdef CONFIG_USE_OF
void *dtb_start = __dtb_start;
#endif

extern unsigned long loops_per_jiffy;

/* Command line specified as configuration option. */

static char __initdata command_line[COMMAND_LINE_SIZE];

#ifdef CONFIG_CMDLINE_BOOL
static char default_command_line[COMMAND_LINE_SIZE] __initdata = CONFIG_CMDLINE;
#endif

#ifdef CONFIG_PARSE_BOOTPARAM
/*
 * Boot parameter parsing.
 *
 * The Xtensa port uses a list of variable-sized tags to pass data to
 * the kernel. The first tag must be a BP_TAG_FIRST tag for the list
 * to be recognised. The list is terminated with a zero-sized
 * BP_TAG_LAST tag.
 */

typedef struct tagtable {
	u32 tag;
	int (*parse)(const bp_tag_t*);
} tagtable_t;

#define __tagtable(tag, fn) static tagtable_t __tagtable_##fn 		\
	__section(".taglist") __attribute__((used)) = { tag, fn }

/* parse current tag */

static int __init parse_tag_mem(const bp_tag_t *tag)
{
	struct bp_meminfo *mi = (struct bp_meminfo *)(tag->data);

	if (mi->type != MEMORY_TYPE_CONVENTIONAL)
		return -1;

	return memblock_add(mi->start, mi->end - mi->start);
}

__tagtable(BP_TAG_MEMORY, parse_tag_mem);

#ifdef CONFIG_BLK_DEV_INITRD

static int __init parse_tag_initrd(const bp_tag_t* tag)
{
	struct bp_meminfo *mi = (struct bp_meminfo *)(tag->data);

	initrd_start = (unsigned long)__va(mi->start);
	initrd_end = (unsigned long)__va(mi->end);

	return 0;
}

__tagtable(BP_TAG_INITRD, parse_tag_initrd);

#endif /* CONFIG_BLK_DEV_INITRD */

#ifdef CONFIG_USE_OF

static int __init parse_tag_fdt(const bp_tag_t *tag)
{
	dtb_start = __va(tag->data[0]);
	return 0;
}

__tagtable(BP_TAG_FDT, parse_tag_fdt);

#endif /* CONFIG_USE_OF */

static int __init parse_tag_cmdline(const bp_tag_t* tag)
{
	strscpy(command_line, (char *)(tag->data), COMMAND_LINE_SIZE);
	return 0;
}

__tagtable(BP_TAG_COMMAND_LINE, parse_tag_cmdline);

static int __init parse_bootparam(const bp_tag_t* tag)
{
	extern tagtable_t __tagtable_begin, __tagtable_end;
	tagtable_t *t;

	/* Boot parameters must start with a BP_TAG_FIRST tag. */

	if (tag->id != BP_TAG_FIRST) {
		pr_warn("Invalid boot parameters!\n");
		return 0;
	}

	tag = (bp_tag_t*)((unsigned long)tag + sizeof(bp_tag_t) + tag->size);

	/* Parse all tags. */

	while (tag != NULL && tag->id != BP_TAG_LAST) {
		for (t = &__tagtable_begin; t < &__tagtable_end; t++) {
			if (tag->id == t->tag) {
				t->parse(tag);
				break;
			}
		}
		if (t == &__tagtable_end)
			pr_warn("Ignoring tag 0x%08x\n", tag->id);
		tag = (bp_tag_t*)((unsigned long)(tag + 1) + tag->size);
	}

	return 0;
}
#else
static int __init parse_bootparam(const bp_tag_t *tag)
{
	pr_info("Ignoring boot parameters at %p\n", tag);
	return 0;
}
#endif

#ifdef CONFIG_USE_OF

#if !XCHAL_HAVE_PTP_MMU || XCHAL_HAVE_SPANNING_WAY
unsigned long xtensa_kio_paddr = XCHAL_KIO_DEFAULT_PADDR;
EXPORT_SYMBOL(xtensa_kio_paddr);

static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
		int depth, void *data)
{
	const __be32 *ranges;
	int len;

	if (depth > 1)
		return 0;

	if (!of_flat_dt_is_compatible(node, "simple-bus"))
		return 0;

	ranges = of_get_flat_dt_prop(node, "ranges", &len);
	if (!ranges)
		return 1;
	if (len == 0)
		return 1;

	xtensa_kio_paddr = of_read_ulong(ranges+1, 1);
	/* round down to nearest 256MB boundary */
	xtensa_kio_paddr &= 0xf0000000;

	init_kio();

	return 1;
}
#else
static int __init xtensa_dt_io_area(unsigned long node, const char *uname,
		int depth, void *data)
{
	return 1;
}
#endif

void __init early_init_devtree(void *params)
{
	early_init_dt_scan(params);
	of_scan_flat_dt(xtensa_dt_io_area, NULL);

	if (!command_line[0])
		strscpy(command_line, boot_command_line, COMMAND_LINE_SIZE);
}

#endif /* CONFIG_USE_OF */

/*
 * Initialize architecture. (Early stage)
 */

void __init init_arch(bp_tag_t *bp_start)
{
	/* Initialize basic exception handling if configuration may need it */

	if (IS_ENABLED(CONFIG_KASAN) ||
	    IS_ENABLED(CONFIG_XTENSA_LOAD_STORE))
		early_trap_init();

	/* Initialize MMU. */

	init_mmu();

	/* Initialize initial KASAN shadow map */

	kasan_early_init();

	/* Parse boot parameters */

	if (bp_start)
		parse_bootparam(bp_start);

#ifdef CONFIG_USE_OF
	early_init_devtree(dtb_start);
#endif

#ifdef CONFIG_CMDLINE_BOOL
	if (!command_line[0])
		strscpy(command_line, default_command_line, COMMAND_LINE_SIZE);
#endif

	/* Early hook for platforms */

	platform_init(bp_start);
}

/*
 * Initialize system. Setup memory and reserve regions.
 */

static inline int __init_memblock mem_reserve(unsigned long start,
					      unsigned long end)
{
	return memblock_reserve(start, end - start);
}

void __init setup_arch(char **cmdline_p)
{
	pr_info("config ID: %08x:%08x\n",
		xtensa_get_sr(SREG_EPC), xtensa_get_sr(SREG_EXCSAVE));
	if (xtensa_get_sr(SREG_EPC) != XCHAL_HW_CONFIGID0 ||
	    xtensa_get_sr(SREG_EXCSAVE) != XCHAL_HW_CONFIGID1)
		pr_info("built for config ID: %08x:%08x\n",
			XCHAL_HW_CONFIGID0, XCHAL_HW_CONFIGID1);

	*cmdline_p = command_line;
	platform_setup(cmdline_p);
	strscpy(boot_command_line, *cmdline_p, COMMAND_LINE_SIZE);

	/* Reserve some memory regions */

#ifdef CONFIG_BLK_DEV_INITRD
	if (initrd_start < initrd_end &&
	    !mem_reserve(__pa(initrd_start), __pa(initrd_end)))
		initrd_below_start_ok = 1;
	else
		initrd_start = 0;
#endif

	mem_reserve(__pa(_stext), __pa(_end));
#ifdef CONFIG_XIP_KERNEL
#ifdef CONFIG_VECTORS_ADDR
	mem_reserve(__pa(_xip_text_start), __pa(_xip_text_end));
#endif
	mem_reserve(__pa(_xip_start), __pa(_xip_end));
#endif

#ifdef CONFIG_VECTORS_ADDR
#ifdef SUPPORT_WINDOWED
	mem_reserve(__pa(_WindowVectors_text_start),
		    __pa(_WindowVectors_text_end));
#endif

	mem_reserve(__pa(_DebugInterruptVector_text_start),
		    __pa(_DebugInterruptVector_text_end));

	mem_reserve(__pa(_KernelExceptionVector_text_start),
		    __pa(_KernelExceptionVector_text_end));

	mem_reserve(__pa(_UserExceptionVector_text_start),
		    __pa(_UserExceptionVector_text_end));

	mem_reserve(__pa(_DoubleExceptionVector_text_start),
		    __pa(_DoubleExceptionVector_text_end));

	mem_reserve(__pa(_exception_text_start),
		    __pa(_exception_text_end));
#if XCHAL_EXCM_LEVEL >= 2
	mem_reserve(__pa(_Level2InterruptVector_text_start),
		    __pa(_Level2InterruptVector_text_end));
#endif
#if XCHAL_EXCM_LEVEL >= 3
	mem_reserve(__pa(_Level3InterruptVector_text_start),
		    __pa(_Level3InterruptVector_text_end));
#endif
#if XCHAL_EXCM_LEVEL >= 4
	mem_reserve(__pa(_Level4InterruptVector_text_start),
		    __pa(_Level4InterruptVector_text_end));
#endif
#if XCHAL_EXCM_LEVEL >= 5
	mem_reserve(__pa(_Level5InterruptVector_text_start),
		    __pa(_Level5InterruptVector_text_end));
#endif
#if XCHAL_EXCM_LEVEL >= 6
	mem_reserve(__pa(_Level6InterruptVector_text_start),
		    __pa(_Level6InterruptVector_text_end));
#endif

#endif /* CONFIG_VECTORS_ADDR */

#ifdef CONFIG_SECONDARY_RESET_VECTOR
	mem_reserve(__pa(_SecondaryResetVector_text_start),
		    __pa(_SecondaryResetVector_text_end));
#endif
	parse_early_param();
	bootmem_init();
	kasan_init();
	unflatten_and_copy_device_tree();

#ifdef CONFIG_SMP
	smp_init_cpus();
#endif

	paging_init();
	zones_init();

#ifdef CONFIG_VT
# if defined(CONFIG_VGA_CONSOLE)
	conswitchp = &vga_con;
# endif
#endif
}

static DEFINE_PER_CPU(struct cpu, cpu_data);

static int __init topology_init(void)
{
	int i;

	for_each_possible_cpu(i) {
		struct cpu *cpu = &per_cpu(cpu_data, i);
		cpu->hotpluggable = !!i;
		register_cpu(cpu, i);
	}

	return 0;
}
subsys_initcall(topology_init);

void cpu_reset(void)
{
#if XCHAL_HAVE_PTP_MMU && IS_ENABLED(CONFIG_MMU)
	local_irq_disable();
	/*
	 * We have full MMU: all autoload ways, ways 7, 8 and 9 of DTLB must
	 * be flushed.
	 * Way 4 is not currently used by linux.
	 * Ways 5 and 6 shall not be touched on MMUv2 as they are hardwired.
	 * Way 5 shall be flushed and way 6 shall be set to identity mapping
	 * on MMUv3.
	 */
	local_flush_tlb_all();
	invalidate_page_directory();
#if XCHAL_HAVE_SPANNING_WAY
	/* MMU v3 */
	{
		unsigned long vaddr = (unsigned long)cpu_reset;
		unsigned long paddr = __pa(vaddr);
		unsigned long tmpaddr = vaddr + SZ_512M;
		unsigned long tmp0, tmp1, tmp2, tmp3;

		/*
		 * Find a place for the temporary mapping. It must not be
		 * in the same 512MB region with vaddr or paddr, otherwise
		 * there may be multihit exception either on entry to the
		 * temporary mapping, or on entry to the identity mapping.
		 * (512MB is the biggest page size supported by TLB.)
		 */
		while (((tmpaddr ^ paddr) & -SZ_512M) == 0)
			tmpaddr += SZ_512M;

		/* Invalidate mapping in the selected temporary area */
		if (itlb_probe(tmpaddr) & BIT(ITLB_HIT_BIT))
			invalidate_itlb_entry(itlb_probe(tmpaddr));
		if (itlb_probe(tmpaddr + PAGE_SIZE) & BIT(ITLB_HIT_BIT))
			invalidate_itlb_entry(itlb_probe(tmpaddr + PAGE_SIZE));

		/*
		 * Map two consecutive pages starting at the physical address
		 * of this function to the temporary mapping area.
		 */
		write_itlb_entry(__pte((paddr & PAGE_MASK) |
				       _PAGE_HW_VALID |
				       _PAGE_HW_EXEC |
				       _PAGE_CA_BYPASS),
				 tmpaddr & PAGE_MASK);
		write_itlb_entry(__pte(((paddr & PAGE_MASK) + PAGE_SIZE) |
				       _PAGE_HW_VALID |
				       _PAGE_HW_EXEC |
				       _PAGE_CA_BYPASS),
				 (tmpaddr & PAGE_MASK) + PAGE_SIZE);

		/* Reinitialize TLB */
		__asm__ __volatile__ ("movi	%0, 1f\n\t"
				      "movi	%3, 2f\n\t"
				      "add	%0, %0, %4\n\t"
				      "add	%3, %3, %5\n\t"
				      "jx	%0\n"
				      /*
				       * No literal, data or stack access
				       * below this point
				       */
				      "1:\n\t"
				      /* Initialize *tlbcfg */
				      "movi	%0, 0\n\t"
				      "wsr	%0, itlbcfg\n\t"
				      "wsr	%0, dtlbcfg\n\t"
				      /* Invalidate TLB way 5 */
				      "movi	%0, 4\n\t"
				      "movi	%1, 5\n"
				      "1:\n\t"
				      "iitlb	%1\n\t"
				      "idtlb	%1\n\t"
				      "add	%1, %1, %6\n\t"
				      "addi	%0, %0, -1\n\t"
				      "bnez	%0, 1b\n\t"
				      /* Initialize TLB way 6 */
				      "movi	%0, 7\n\t"
				      "addi	%1, %9, 3\n\t"
				      "addi	%2, %9, 6\n"
				      "1:\n\t"
				      "witlb	%1, %2\n\t"
				      "wdtlb	%1, %2\n\t"
				      "add	%1, %1, %7\n\t"
				      "add	%2, %2, %7\n\t"
				      "addi	%0, %0, -1\n\t"
				      "bnez	%0, 1b\n\t"
				      "isync\n\t"
				      /* Jump to identity mapping */
				      "jx	%3\n"
				      "2:\n\t"
				      /* Complete way 6 initialization */
				      "witlb	%1, %2\n\t"
				      "wdtlb	%1, %2\n\t"
				      /* Invalidate temporary mapping */
				      "sub	%0, %9, %7\n\t"
				      "iitlb	%0\n\t"
				      "add	%0, %0, %8\n\t"
				      "iitlb	%0"
				      : "=&a"(tmp0), "=&a"(tmp1), "=&a"(tmp2),
					"=&a"(tmp3)
				      : "a"(tmpaddr - vaddr),
					"a"(paddr - vaddr),
					"a"(SZ_128M), "a"(SZ_512M),
					"a"(PAGE_SIZE),
					"a"((tmpaddr + SZ_512M) & PAGE_MASK)
				      : "memory");
	}
#endif
#endif
	__asm__ __volatile__ ("movi	a2, 0\n\t"
			      "wsr	a2, icountlevel\n\t"
			      "movi	a2, 0\n\t"
			      "wsr	a2, icount\n\t"
#if XCHAL_NUM_IBREAK > 0
			      "wsr	a2, ibreakenable\n\t"
#endif
#if XCHAL_HAVE_LOOPS
			      "wsr	a2, lcount\n\t"
#endif
			      "movi	a2, 0x1f\n\t"
			      "wsr	a2, ps\n\t"
			      "isync\n\t"
			      "jx	%0\n\t"
			      :
			      : "a" (XCHAL_RESET_VECTOR_VADDR)
			      : "a2");
	for (;;)
		;
}

void machine_restart(char * cmd)
{
	local_irq_disable();
	smp_send_stop();
	do_kernel_restart(cmd);
	pr_err("Reboot failed -- System halted\n");
	while (1)
		cpu_relax();
}

void machine_halt(void)
{
	local_irq_disable();
	smp_send_stop();
	do_kernel_power_off();
	while (1)
		cpu_relax();
}

void machine_power_off(void)
{
	local_irq_disable();
	smp_send_stop();
	do_kernel_power_off();
	while (1)
		cpu_relax();
}
#ifdef CONFIG_PROC_FS

/*
 * Display some core information through /proc/cpuinfo.
 */

static int
c_show(struct seq_file *f, void *slot)
{
	/* high-level stuff */
	seq_printf(f, "CPU count\t: %u\n"
		      "CPU list\t: %*pbl\n"
		      "vendor_id\t: Tensilica\n"
		      "model\t\t: Xtensa " XCHAL_HW_VERSION_NAME "\n"
		      "core ID\t\t: " XCHAL_CORE_ID "\n"
		      "build ID\t: 0x%x\n"
		      "config ID\t: %08x:%08x\n"
		      "byte order\t: %s\n"
		      "cpu MHz\t\t: %lu.%02lu\n"
		      "bogomips\t: %lu.%02lu\n",
		      num_online_cpus(),
		      cpumask_pr_args(cpu_online_mask),
		      XCHAL_BUILD_UNIQUE_ID,
		      xtensa_get_sr(SREG_EPC), xtensa_get_sr(SREG_EXCSAVE),
		      XCHAL_HAVE_BE ?  "big" : "little",
		      ccount_freq/1000000,
		      (ccount_freq/10000) % 100,
		      loops_per_jiffy/(500000/HZ),
		      (loops_per_jiffy/(5000/HZ)) % 100);
	seq_puts(f, "flags\t\t: "
#if XCHAL_HAVE_NMI
		     "nmi "
#endif
#if XCHAL_HAVE_DEBUG
		     "debug "
# if XCHAL_HAVE_OCD
		     "ocd "
# endif
#if XCHAL_HAVE_TRAX
		     "trax "
#endif
#if XCHAL_NUM_PERF_COUNTERS
		     "perf "
#endif
#endif
#if XCHAL_HAVE_DENSITY
	    	     "density "
#endif
#if XCHAL_HAVE_BOOLEANS
		     "boolean "
#endif
#if XCHAL_HAVE_LOOPS
		     "loop "
#endif
#if XCHAL_HAVE_NSA
		     "nsa "
#endif
#if XCHAL_HAVE_MINMAX
		     "minmax "
#endif
#if XCHAL_HAVE_SEXT
		     "sext "
#endif
#if XCHAL_HAVE_CLAMPS
		     "clamps "
#endif
#if XCHAL_HAVE_MAC16
		     "mac16 "
#endif
#if XCHAL_HAVE_MUL16
		     "mul16 "
#endif
#if XCHAL_HAVE_MUL32
		     "mul32 "
#endif
#if XCHAL_HAVE_MUL32_HIGH
		     "mul32h "
#endif
#if XCHAL_HAVE_FP
		     "fpu "
#endif
#if XCHAL_HAVE_S32C1I
		     "s32c1i "
#endif
#if XCHAL_HAVE_EXCLUSIVE
		     "exclusive "
#endif
		     "\n");

	/* Registers. */
	seq_printf(f,"physical aregs\t: %d\n"
		     "misc regs\t: %d\n"
		     "ibreak\t\t: %d\n"
		     "dbreak\t\t: %d\n"
		     "perf counters\t: %d\n",
		     XCHAL_NUM_AREGS,
		     XCHAL_NUM_MISC_REGS,
		     XCHAL_NUM_IBREAK,
		     XCHAL_NUM_DBREAK,
		     XCHAL_NUM_PERF_COUNTERS);


	/* Interrupt. */
	seq_printf(f,"num ints\t: %d\n"
		     "ext ints\t: %d\n"
		     "int levels\t: %d\n"
		     "timers\t\t: %d\n"
		     "debug level\t: %d\n",
		     XCHAL_NUM_INTERRUPTS,
		     XCHAL_NUM_EXTINTERRUPTS,
		     XCHAL_NUM_INTLEVELS,
		     XCHAL_NUM_TIMERS,
		     XCHAL_DEBUGLEVEL);

	/* Cache */
	seq_printf(f,"icache line size: %d\n"
		     "icache ways\t: %d\n"
		     "icache size\t: %d\n"
		     "icache flags\t: "
#if XCHAL_ICACHE_LINE_LOCKABLE
		     "lock "
#endif
		     "\n"
		     "dcache line size: %d\n"
		     "dcache ways\t: %d\n"
		     "dcache size\t: %d\n"
		     "dcache flags\t: "
#if XCHAL_DCACHE_IS_WRITEBACK
		     "writeback "
#endif
#if XCHAL_DCACHE_LINE_LOCKABLE
		     "lock "
#endif
		     "\n",
		     XCHAL_ICACHE_LINESIZE,
		     XCHAL_ICACHE_WAYS,
		     XCHAL_ICACHE_SIZE,
		     XCHAL_DCACHE_LINESIZE,
		     XCHAL_DCACHE_WAYS,
		     XCHAL_DCACHE_SIZE);

	return 0;
}

/*
 * We show only CPU #0 info.
 */
static void *
c_start(struct seq_file *f, loff_t *pos)
{
	return (*pos == 0) ? (void *)1 : NULL;
}

static void *
c_next(struct seq_file *f, void *v, loff_t *pos)
{
	++*pos;
	return c_start(f, pos);
}

static void
c_stop(struct seq_file *f, void *v)
{
}

const struct seq_operations cpuinfo_op =
{
	.start	= c_start,
	.next	= c_next,
	.stop	= c_stop,
	.show	= c_show,
};

#endif /* CONFIG_PROC_FS */