/*
 * Copyright (C) 2004, 2007-2010, 2011-2012 Synopsys, Inc. (www.synopsys.com)
 *
 * 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.
 */

#include <linux/seq_file.h>
#include <linux/fs.h>
#include <linux/delay.h>
#include <linux/root_dev.h>
#include <linux/clk-provider.h>
#include <linux/clocksource.h>
#include <linux/console.h>
#include <linux/module.h>
#include <linux/cpu.h>
#include <linux/of_fdt.h>
#include <linux/of.h>
#include <linux/cache.h>
#include <asm/sections.h>
#include <asm/arcregs.h>
#include <asm/tlb.h>
#include <asm/setup.h>
#include <asm/page.h>
#include <asm/irq.h>
#include <asm/unwind.h>
#include <asm/mach_desc.h>
#include <asm/smp.h>

#define FIX_PTR(x)  __asm__ __volatile__(";" : "+r"(x))

unsigned int intr_to_DE_cnt;

/* Part of U-boot ABI: see head.S */
int __initdata uboot_tag;
char __initdata *uboot_arg;

const struct machine_desc *machine_desc;

struct task_struct *_current_task[NR_CPUS];	/* For stack switching */

struct cpuinfo_arc cpuinfo_arc700[NR_CPUS];

static const struct id_to_str arc_cpu_rel[] = {
#ifdef CONFIG_ISA_ARCOMPACT
	{ 0x34, "R4.10"},
	{ 0x35, "R4.11"},
#else
	{ 0x51, "R2.0" },
	{ 0x52, "R2.1" },
	{ 0x53, "R3.0" },
#endif
	{ 0x00, NULL   }
};

static const struct id_to_str arc_cpu_nm[] = {
#ifdef CONFIG_ISA_ARCOMPACT
	{ 0x20, "ARC 600"   },
	{ 0x30, "ARC 770"   },  /* 750 identified seperately */
#else
	{ 0x40, "ARC EM"  },
	{ 0x50, "ARC HS38"  },
#endif
	{ 0x00, "Unknown"   }
};

static void read_decode_ccm_bcr(struct cpuinfo_arc *cpu)
{
	if (is_isa_arcompact()) {
		struct bcr_iccm_arcompact iccm;
		struct bcr_dccm_arcompact dccm;

		READ_BCR(ARC_REG_ICCM_BUILD, iccm);
		if (iccm.ver) {
			cpu->iccm.sz = 4096 << iccm.sz;	/* 8K to 512K */
			cpu->iccm.base_addr = iccm.base << 16;
		}

		READ_BCR(ARC_REG_DCCM_BUILD, dccm);
		if (dccm.ver) {
			unsigned long base;
			cpu->dccm.sz = 2048 << dccm.sz;	/* 2K to 256K */

			base = read_aux_reg(ARC_REG_DCCM_BASE_BUILD);
			cpu->dccm.base_addr = base & ~0xF;
		}
	} else {
		struct bcr_iccm_arcv2 iccm;
		struct bcr_dccm_arcv2 dccm;
		unsigned long region;

		READ_BCR(ARC_REG_ICCM_BUILD, iccm);
		if (iccm.ver) {
			cpu->iccm.sz = 256 << iccm.sz00;	/* 512B to 16M */
			if (iccm.sz00 == 0xF && iccm.sz01 > 0)
				cpu->iccm.sz <<= iccm.sz01;

			region = read_aux_reg(ARC_REG_AUX_ICCM);
			cpu->iccm.base_addr = region & 0xF0000000;
		}

		READ_BCR(ARC_REG_DCCM_BUILD, dccm);
		if (dccm.ver) {
			cpu->dccm.sz = 256 << dccm.sz0;
			if (dccm.sz0 == 0xF && dccm.sz1 > 0)
				cpu->dccm.sz <<= dccm.sz1;

			region = read_aux_reg(ARC_REG_AUX_DCCM);
			cpu->dccm.base_addr = region & 0xF0000000;
		}
	}
}

static void read_arc_build_cfg_regs(void)
{
	struct bcr_timer timer;
	struct bcr_generic bcr;
	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
	const struct id_to_str *tbl;

	FIX_PTR(cpu);

	READ_BCR(AUX_IDENTITY, cpu->core);
	READ_BCR(ARC_REG_ISA_CFG_BCR, cpu->isa);

	for (tbl = &arc_cpu_rel[0]; tbl->id != 0; tbl++) {
		if (cpu->core.family == tbl->id) {
			cpu->details = tbl->str;
			break;
		}
	}

	for (tbl = &arc_cpu_nm[0]; tbl->id != 0; tbl++) {
		if ((cpu->core.family & 0xF0) == tbl->id)
			break;
	}
	cpu->name = tbl->str;

	READ_BCR(ARC_REG_TIMERS_BCR, timer);
	cpu->extn.timer0 = timer.t0;
	cpu->extn.timer1 = timer.t1;
	cpu->extn.rtc = timer.rtc;

	cpu->vec_base = read_aux_reg(AUX_INTR_VEC_BASE);

	READ_BCR(ARC_REG_MUL_BCR, cpu->extn_mpy);

	cpu->extn.norm = read_aux_reg(ARC_REG_NORM_BCR) > 1 ? 1 : 0; /* 2,3 */
	cpu->extn.barrel = read_aux_reg(ARC_REG_BARREL_BCR) > 1 ? 1 : 0; /* 2,3 */
	cpu->extn.swap = read_aux_reg(ARC_REG_SWAP_BCR) ? 1 : 0;        /* 1,3 */
	cpu->extn.crc = read_aux_reg(ARC_REG_CRC_BCR) ? 1 : 0;
	cpu->extn.minmax = read_aux_reg(ARC_REG_MIXMAX_BCR) > 1 ? 1 : 0; /* 2 */
	cpu->extn.swape = (cpu->core.family >= 0x34) ? 1 :
				IS_ENABLED(CONFIG_ARC_HAS_SWAPE);

	READ_BCR(ARC_REG_XY_MEM_BCR, cpu->extn_xymem);

	/* Read CCM BCRs for boot reporting even if not enabled in Kconfig */
	read_decode_ccm_bcr(cpu);

	read_decode_mmu_bcr();
	read_decode_cache_bcr();

	if (is_isa_arcompact()) {
		struct bcr_fp_arcompact sp, dp;
		struct bcr_bpu_arcompact bpu;

		READ_BCR(ARC_REG_FP_BCR, sp);
		READ_BCR(ARC_REG_DPFP_BCR, dp);
		cpu->extn.fpu_sp = sp.ver ? 1 : 0;
		cpu->extn.fpu_dp = dp.ver ? 1 : 0;

		READ_BCR(ARC_REG_BPU_BCR, bpu);
		cpu->bpu.ver = bpu.ver;
		cpu->bpu.full = bpu.fam ? 1 : 0;
		if (bpu.ent) {
			cpu->bpu.num_cache = 256 << (bpu.ent - 1);
			cpu->bpu.num_pred = 256 << (bpu.ent - 1);
		}
	} else {
		struct bcr_fp_arcv2 spdp;
		struct bcr_bpu_arcv2 bpu;

		READ_BCR(ARC_REG_FP_V2_BCR, spdp);
		cpu->extn.fpu_sp = spdp.sp ? 1 : 0;
		cpu->extn.fpu_dp = spdp.dp ? 1 : 0;

		READ_BCR(ARC_REG_BPU_BCR, bpu);
		cpu->bpu.ver = bpu.ver;
		cpu->bpu.full = bpu.ft;
		cpu->bpu.num_cache = 256 << bpu.bce;
		cpu->bpu.num_pred = 2048 << bpu.pte;
	}

	READ_BCR(ARC_REG_AP_BCR, bcr);
	cpu->extn.ap = bcr.ver ? 1 : 0;

	READ_BCR(ARC_REG_SMART_BCR, bcr);
	cpu->extn.smart = bcr.ver ? 1 : 0;

	READ_BCR(ARC_REG_RTT_BCR, bcr);
	cpu->extn.rtt = bcr.ver ? 1 : 0;

	cpu->extn.debug = cpu->extn.ap | cpu->extn.smart | cpu->extn.rtt;

	/* some hacks for lack of feature BCR info in old ARC700 cores */
	if (is_isa_arcompact()) {
		if (!cpu->isa.ver)	/* ISA BCR absent, use Kconfig info */
			cpu->isa.atomic = IS_ENABLED(CONFIG_ARC_HAS_LLSC);
		else
			cpu->isa.atomic = cpu->isa.atomic1;

		cpu->isa.be = IS_ENABLED(CONFIG_CPU_BIG_ENDIAN);

		 /* there's no direct way to distinguish 750 vs. 770 */
		if (unlikely(cpu->core.family < 0x34 || cpu->mmu.ver < 3))
			cpu->name = "ARC750";
	}
}

static char *arc_cpu_mumbojumbo(int cpu_id, char *buf, int len)
{
	struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];
	struct bcr_identity *core = &cpu->core;
	int i, n = 0;

	FIX_PTR(cpu);

	n += scnprintf(buf + n, len - n,
		       "\nIDENTITY\t: ARCVER [%#02x] ARCNUM [%#02x] CHIPID [%#4x]\n",
		       core->family, core->cpu_id, core->chip_id);

	n += scnprintf(buf + n, len - n, "processor [%d]\t: %s %s (%s ISA) %s\n",
		       cpu_id, cpu->name, cpu->details,
		       is_isa_arcompact() ? "ARCompact" : "ARCv2",
		       IS_AVAIL1(cpu->isa.be, "[Big-Endian]"));

	n += scnprintf(buf + n, len - n, "Timers\t\t: %s%s%s%s%s%s\nISA Extn\t: ",
		       IS_AVAIL1(cpu->extn.timer0, "Timer0 "),
		       IS_AVAIL1(cpu->extn.timer1, "Timer1 "),
		       IS_AVAIL2(cpu->extn.rtc, "RTC [UP 64-bit] ", CONFIG_ARC_TIMERS_64BIT),
		       IS_AVAIL2(cpu->extn.gfrc, "GFRC [SMP 64-bit] ", CONFIG_ARC_TIMERS_64BIT));

	n += i = scnprintf(buf + n, len - n, "%s%s%s%s%s",
			   IS_AVAIL2(cpu->isa.atomic, "atomic ", CONFIG_ARC_HAS_LLSC),
			   IS_AVAIL2(cpu->isa.ldd, "ll64 ", CONFIG_ARC_HAS_LL64),
			   IS_AVAIL1(cpu->isa.unalign, "unalign (not used)"));

	if (i)
		n += scnprintf(buf + n, len - n, "\n\t\t: ");

	if (cpu->extn_mpy.ver) {
		if (cpu->extn_mpy.ver <= 0x2) {	/* ARCompact */
			n += scnprintf(buf + n, len - n, "mpy ");
		} else {
			int opt = 2;	/* stock MPY/MPYH */

			if (cpu->extn_mpy.dsp)	/* OPT 7-9 */
				opt = cpu->extn_mpy.dsp + 6;

			n += scnprintf(buf + n, len - n, "mpy[opt %d] ", opt);
		}
	}

	n += scnprintf(buf + n, len - n, "%s%s%s%s%s%s%s%s\n",
		       IS_AVAIL1(cpu->isa.div_rem, "div_rem "),
		       IS_AVAIL1(cpu->extn.norm, "norm "),
		       IS_AVAIL1(cpu->extn.barrel, "barrel-shift "),
		       IS_AVAIL1(cpu->extn.swap, "swap "),
		       IS_AVAIL1(cpu->extn.minmax, "minmax "),
		       IS_AVAIL1(cpu->extn.crc, "crc "),
		       IS_AVAIL2(cpu->extn.swape, "swape", CONFIG_ARC_HAS_SWAPE));

	if (cpu->bpu.ver)
		n += scnprintf(buf + n, len - n,
			      "BPU\t\t: %s%s match, cache:%d, Predict Table:%d\n",
			      IS_AVAIL1(cpu->bpu.full, "full"),
			      IS_AVAIL1(!cpu->bpu.full, "partial"),
			      cpu->bpu.num_cache, cpu->bpu.num_pred);

	return buf;
}

static char *arc_extn_mumbojumbo(int cpu_id, char *buf, int len)
{
	int n = 0;
	struct cpuinfo_arc *cpu = &cpuinfo_arc700[cpu_id];

	FIX_PTR(cpu);

	n += scnprintf(buf + n, len - n, "Vector Table\t: %#x\n", cpu->vec_base);

	if (cpu->extn.fpu_sp || cpu->extn.fpu_dp)
		n += scnprintf(buf + n, len - n, "FPU\t\t: %s%s\n",
			       IS_AVAIL1(cpu->extn.fpu_sp, "SP "),
			       IS_AVAIL1(cpu->extn.fpu_dp, "DP "));

	if (cpu->extn.debug)
		n += scnprintf(buf + n, len - n, "DEBUG\t\t: %s%s%s\n",
			       IS_AVAIL1(cpu->extn.ap, "ActionPoint "),
			       IS_AVAIL1(cpu->extn.smart, "smaRT "),
			       IS_AVAIL1(cpu->extn.rtt, "RTT "));

	if (cpu->dccm.sz || cpu->iccm.sz)
		n += scnprintf(buf + n, len - n, "Extn [CCM]\t: DCCM @ %x, %d KB / ICCM: @ %x, %d KB\n",
			       cpu->dccm.base_addr, TO_KB(cpu->dccm.sz),
			       cpu->iccm.base_addr, TO_KB(cpu->iccm.sz));

	n += scnprintf(buf + n, len - n, "OS ABI [v%d]\t: %s\n",
			EF_ARC_OSABI_CURRENT >> 8,
			EF_ARC_OSABI_CURRENT == EF_ARC_OSABI_V3 ?
			"no-legacy-syscalls" : "64-bit data any register aligned");

	return buf;
}

static void arc_chk_core_config(void)
{
	struct cpuinfo_arc *cpu = &cpuinfo_arc700[smp_processor_id()];
	int fpu_enabled;

	if (!cpu->extn.timer0)
		panic("Timer0 is not present!\n");

	if (!cpu->extn.timer1)
		panic("Timer1 is not present!\n");

#ifdef CONFIG_ARC_HAS_DCCM
	/*
	 * DCCM can be arbit placed in hardware.
	 * Make sure it's placement/sz matches what Linux is built with
	 */
	if ((unsigned int)__arc_dccm_base != cpu->dccm.base_addr)
		panic("Linux built with incorrect DCCM Base address\n");

	if (CONFIG_ARC_DCCM_SZ != cpu->dccm.sz)
		panic("Linux built with incorrect DCCM Size\n");
#endif

#ifdef CONFIG_ARC_HAS_ICCM
	if (CONFIG_ARC_ICCM_SZ != cpu->iccm.sz)
		panic("Linux built with incorrect ICCM Size\n");
#endif

	/*
	 * FP hardware/software config sanity
	 * -If hardware contains DPFP, kernel needs to save/restore FPU state
	 * -If not, it will crash trying to save/restore the non-existant regs
	 *
	 * (only DPDP checked since SP has no arch visible regs)
	 */
	fpu_enabled = IS_ENABLED(CONFIG_ARC_FPU_SAVE_RESTORE);

	if (cpu->extn.fpu_dp && !fpu_enabled)
		pr_warn("CONFIG_ARC_FPU_SAVE_RESTORE needed for working apps\n");
	else if (!cpu->extn.fpu_dp && fpu_enabled)
		panic("FPU non-existent, disable CONFIG_ARC_FPU_SAVE_RESTORE\n");
}

/*
 * Initialize and setup the processor core
 * This is called by all the CPUs thus should not do special case stuff
 *    such as only for boot CPU etc
 */

void setup_processor(void)
{
	char str[512];
	int cpu_id = smp_processor_id();

	read_arc_build_cfg_regs();
	arc_init_IRQ();

	printk(arc_cpu_mumbojumbo(cpu_id, str, sizeof(str)));

	arc_mmu_init();
	arc_cache_init();

	printk(arc_extn_mumbojumbo(cpu_id, str, sizeof(str)));
	printk(arc_platform_smp_cpuinfo());

	arc_chk_core_config();
}

static inline int is_kernel(unsigned long addr)
{
	if (addr >= (unsigned long)_stext && addr <= (unsigned long)_end)
		return 1;
	return 0;
}

void __init setup_arch(char **cmdline_p)
{
#ifdef CONFIG_ARC_UBOOT_SUPPORT
	/* make sure that uboot passed pointer to cmdline/dtb is valid */
	if (uboot_tag && is_kernel((unsigned long)uboot_arg))
		panic("Invalid uboot arg\n");

	/* See if u-boot passed an external Device Tree blob */
	machine_desc = setup_machine_fdt(uboot_arg);	/* uboot_tag == 2 */
	if (!machine_desc)
#endif
	{
		/* No, so try the embedded one */
		machine_desc = setup_machine_fdt(__dtb_start);
		if (!machine_desc)
			panic("Embedded DT invalid\n");

		/*
		 * If we are here, it is established that @uboot_arg didn't
		 * point to DT blob. Instead if u-boot says it is cmdline,
		 * append to embedded DT cmdline.
		 * setup_machine_fdt() would have populated @boot_command_line
		 */
		if (uboot_tag == 1) {
			/* Ensure a whitespace between the 2 cmdlines */
			strlcat(boot_command_line, " ", COMMAND_LINE_SIZE);
			strlcat(boot_command_line, uboot_arg,
				COMMAND_LINE_SIZE);
		}
	}

	/* Save unparsed command line copy for /proc/cmdline */
	*cmdline_p = boot_command_line;

	/* To force early parsing of things like mem=xxx */
	parse_early_param();

	/* Platform/board specific: e.g. early console registration */
	if (machine_desc->init_early)
		machine_desc->init_early();

	smp_init_cpus();

	setup_processor();
	setup_arch_memory();

	/* copy flat DT out of .init and then unflatten it */
	unflatten_and_copy_device_tree();

	/* Can be issue if someone passes cmd line arg "ro"
	 * But that is unlikely so keeping it as it is
	 */
	root_mountflags &= ~MS_RDONLY;

#if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
	conswitchp = &dummy_con;
#endif

	arc_unwind_init();
}

/*
 * Called from start_kernel() - boot CPU only
 */
void __init time_init(void)
{
	of_clk_init(NULL);
	clocksource_probe();
}

static int __init customize_machine(void)
{
	if (machine_desc->init_machine)
		machine_desc->init_machine();

	return 0;
}
arch_initcall(customize_machine);

static int __init init_late_machine(void)
{
	if (machine_desc->init_late)
		machine_desc->init_late();

	return 0;
}
late_initcall(init_late_machine);
/*
 *  Get CPU information for use by the procfs.
 */

#define cpu_to_ptr(c)	((void *)(0xFFFF0000 | (unsigned int)(c)))
#define ptr_to_cpu(p)	(~0xFFFF0000UL & (unsigned int)(p))

static int show_cpuinfo(struct seq_file *m, void *v)
{
	char *str;
	int cpu_id = ptr_to_cpu(v);
	struct device_node *core_clk = of_find_node_by_name(NULL, "core_clk");
	u32 freq = 0;

	if (!cpu_online(cpu_id)) {
		seq_printf(m, "processor [%d]\t: Offline\n", cpu_id);
		goto done;
	}

	str = (char *)__get_free_page(GFP_TEMPORARY);
	if (!str)
		goto done;

	seq_printf(m, arc_cpu_mumbojumbo(cpu_id, str, PAGE_SIZE));

	of_property_read_u32(core_clk, "clock-frequency", &freq);
	if (freq)
		seq_printf(m, "CPU speed\t: %u.%02u Mhz\n",
			   freq / 1000000, (freq / 10000) % 100);

	seq_printf(m, "Bogo MIPS\t: %lu.%02lu\n",
		   loops_per_jiffy / (500000 / HZ),
		   (loops_per_jiffy / (5000 / HZ)) % 100);

	seq_printf(m, arc_mmu_mumbojumbo(cpu_id, str, PAGE_SIZE));
	seq_printf(m, arc_cache_mumbojumbo(cpu_id, str, PAGE_SIZE));
	seq_printf(m, arc_extn_mumbojumbo(cpu_id, str, PAGE_SIZE));
	seq_printf(m, arc_platform_smp_cpuinfo());

	free_page((unsigned long)str);
done:
	seq_printf(m, "\n");

	return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
	/*
	 * Callback returns cpu-id to iterator for show routine, NULL to stop.
	 * However since NULL is also a valid cpu-id (0), we use a round-about
	 * way to pass it w/o having to kmalloc/free a 2 byte string.
	 * Encode cpu-id as 0xFFcccc, which is decoded by show routine.
	 */
	return *pos < nr_cpu_ids ? cpu_to_ptr(*pos) : NULL;
}

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

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
};

static DEFINE_PER_CPU(struct cpu, cpu_topology);

static int __init topology_init(void)
{
	int cpu;

	for_each_present_cpu(cpu)
	    register_cpu(&per_cpu(cpu_topology, cpu), cpu);

	return 0;
}

subsys_initcall(topology_init);