/*
 *  Port on Texas Instruments TMS320C6x architecture
 *
 *  Copyright (C) 2004, 2006, 2009, 2010, 2011 Texas Instruments Incorporated
 *  Author: Aurelien Jacquiot (aurelien.jacquiot@jaluna.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/dma-mapping.h>
#include <linux/memblock.h>
#include <linux/seq_file.h>
#include <linux/bootmem.h>
#include <linux/clkdev.h>
#include <linux/initrd.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/of_fdt.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/cache.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/clk.h>
#include <linux/cpu.h>
#include <linux/fs.h>
#include <linux/of.h>
#include <linux/console.h>
#include <linux/screen_info.h>

#include <asm/sections.h>
#include <asm/div64.h>
#include <asm/setup.h>
#include <asm/dscr.h>
#include <asm/clock.h>
#include <asm/soc.h>
#include <asm/special_insns.h>

static const char *c6x_soc_name;

struct screen_info screen_info;

int c6x_num_cores;
EXPORT_SYMBOL_GPL(c6x_num_cores);

unsigned int c6x_silicon_rev;
EXPORT_SYMBOL_GPL(c6x_silicon_rev);

/*
 * Device status register. This holds information
 * about device configuration needed by some drivers.
 */
unsigned int c6x_devstat;
EXPORT_SYMBOL_GPL(c6x_devstat);

/*
 * Some SoCs have fuse registers holding a unique MAC
 * address. This is parsed out of the device tree with
 * the resulting MAC being held here.
 */
unsigned char c6x_fuse_mac[6];

unsigned long memory_start;
unsigned long memory_end;
EXPORT_SYMBOL(memory_end);

unsigned long ram_start;
unsigned long ram_end;

/* Uncached memory for DMA consistent use (memdma=) */
static unsigned long dma_start __initdata;
static unsigned long dma_size __initdata;

struct cpuinfo_c6x {
        const char *cpu_name;
        const char *cpu_voltage;
        const char *mmu;
        const char *fpu;
        char *cpu_rev;
        unsigned int core_id;
        char __cpu_rev[5];
};

static DEFINE_PER_CPU(struct cpuinfo_c6x, cpu_data);

unsigned int ticks_per_ns_scaled;
EXPORT_SYMBOL(ticks_per_ns_scaled);

unsigned int c6x_core_freq;

static void __init get_cpuinfo(void)
{
        unsigned cpu_id, rev_id, csr;
        struct clk *coreclk = clk_get_sys(NULL, "core");
        unsigned long core_khz;
        u64 tmp;
        struct cpuinfo_c6x *p;
        struct device_node *node, *np;

        p = &per_cpu(cpu_data, smp_processor_id());

        if (!IS_ERR(coreclk))
                c6x_core_freq = clk_get_rate(coreclk);
        else {
                printk(KERN_WARNING
                       "Cannot find core clock frequency. Using 700MHz\n");
                c6x_core_freq = 700000000;
        }

        core_khz = c6x_core_freq / 1000;

        tmp = (uint64_t)core_khz << C6X_NDELAY_SCALE;
        do_div(tmp, 1000000);
        ticks_per_ns_scaled = tmp;

        csr = get_creg(CSR);
        cpu_id = csr >> 24;
        rev_id = (csr >> 16) & 0xff;

        p->mmu = "none";
        p->fpu = "none";
        p->cpu_voltage = "unknown";

        switch (cpu_id) {
        case 0:
                p->cpu_name = "C67x";
                p->fpu = "yes";
                break;
        case 2:
                p->cpu_name = "C62x";
                break;
        case 8:
                p->cpu_name = "C64x";
                break;
        case 12:
                p->cpu_name = "C64x";
                break;
        case 16:
                p->cpu_name = "C64x+";
                p->cpu_voltage = "1.2";
                break;
        case 21:
                p->cpu_name = "C66X";
                p->cpu_voltage = "1.2";
                break;
        default:
                p->cpu_name = "unknown";
                break;
        }

        if (cpu_id < 16) {
                switch (rev_id) {
                case 0x1:
                        if (cpu_id > 8) {
                                p->cpu_rev = "DM640/DM641/DM642/DM643";
                                p->cpu_voltage = "1.2 - 1.4";
                        } else {
                                p->cpu_rev = "C6201";
                                p->cpu_voltage = "2.5";
                        }
                        break;
                case 0x2:
                        p->cpu_rev = "C6201B/C6202/C6211";
                        p->cpu_voltage = "1.8";
                        break;
                case 0x3:
                        p->cpu_rev = "C6202B/C6203/C6204/C6205";
                        p->cpu_voltage = "1.5";
                        break;
                case 0x201:
                        p->cpu_rev = "C6701 revision 0 (early CPU)";
                        p->cpu_voltage = "1.8";
                        break;
                case 0x202:
                        p->cpu_rev = "C6701/C6711/C6712";
                        p->cpu_voltage = "1.8";
                        break;
                case 0x801:
                        p->cpu_rev = "C64x";
                        p->cpu_voltage = "1.5";
                        break;
                default:
                        p->cpu_rev = "unknown";
                }
        } else {
                p->cpu_rev = p->__cpu_rev;
                snprintf(p->__cpu_rev, sizeof(p->__cpu_rev), "0x%x", cpu_id);
        }

        p->core_id = get_coreid();

        node = of_find_node_by_name(NULL, "cpus");
        if (node) {
                for_each_child_of_node(node, np)
                        if (!strcmp("cpu", np->name))
                                ++c6x_num_cores;
                of_node_put(node);
        }

        node = of_find_node_by_name(NULL, "soc");
        if (node) {
                if (of_property_read_string(node, "model", &c6x_soc_name))
                        c6x_soc_name = "unknown";
                of_node_put(node);
        } else
                c6x_soc_name = "unknown";

        printk(KERN_INFO "CPU%d: %s rev %s, %s volts, %uMHz\n",
               p->core_id, p->cpu_name, p->cpu_rev,
               p->cpu_voltage, c6x_core_freq / 1000000);
}

/*
 * Early parsing of the command line
 */
static u32 mem_size __initdata;

/* "mem=" parsing. */
static int __init early_mem(char *p)
{
        if (!p)
                return -EINVAL;

        mem_size = memparse(p, &p);
        /* don't remove all of memory when handling "mem={invalid}" */
        if (mem_size == 0)
                return -EINVAL;

        return 0;
}
early_param("mem", early_mem);

/* "memdma=<size>[@<address>]" parsing. */
static int __init early_memdma(char *p)
{
        if (!p)
                return -EINVAL;

        dma_size = memparse(p, &p);
        if (*p == '@')
                dma_start = memparse(p, &p);

        return 0;
}
early_param("memdma", early_memdma);

int __init c6x_add_memory(phys_addr_t start, unsigned long size)
{
        static int ram_found __initdata;

        /* We only handle one bank (the one with PAGE_OFFSET) for now */
        if (ram_found)
                return -EINVAL;

        if (start > PAGE_OFFSET || PAGE_OFFSET >= (start + size))
                return 0;

        ram_start = start;
        ram_end = start + size;

        ram_found = 1;
        return 0;
}

/*
 * Do early machine setup and device tree parsing. This is called very
 * early on the boot process.
 */
notrace void __init machine_init(unsigned long dt_ptr)
{
        void *dtb = __va(dt_ptr);
        void *fdt = _fdt_start;

        /* interrupts must be masked */
        set_creg(IER, 2);

        /*
         * Set the Interrupt Service Table (IST) to the beginning of the
         * vector table.
         */
        set_ist(_vectors_start);

        /*
         * dtb is passed in from bootloader.
         * fdt is linked in blob.
         */
        if (dtb && dtb != fdt)
                fdt = dtb;

        /* Do some early initialization based on the flat device tree */
        early_init_dt_scan(fdt);

        parse_early_param();
}

void __init setup_arch(char **cmdline_p)
{
        int bootmap_size;
        struct memblock_region *reg;

        printk(KERN_INFO "Initializing kernel\n");

        /* Initialize command line */
        *cmdline_p = boot_command_line;

        memory_end = ram_end;
        memory_end &= ~(PAGE_SIZE - 1);

        if (mem_size && (PAGE_OFFSET + PAGE_ALIGN(mem_size)) < memory_end)
                memory_end = PAGE_OFFSET + PAGE_ALIGN(mem_size);

        /* add block that this kernel can use */
        memblock_add(PAGE_OFFSET, memory_end - PAGE_OFFSET);

        /* reserve kernel text/data/bss */
        memblock_reserve(PAGE_OFFSET,
                         PAGE_ALIGN((unsigned long)&_end - PAGE_OFFSET));

        if (dma_size) {
                /* align to cacheability granularity */
                dma_size = CACHE_REGION_END(dma_size);

                if (!dma_start)
                        dma_start = memory_end - dma_size;

                /* align to cacheability granularity */
                dma_start = CACHE_REGION_START(dma_start);

                /* reserve DMA memory taken from kernel memory */
                if (memblock_is_region_memory(dma_start, dma_size))
                        memblock_reserve(dma_start, dma_size);
        }

        memory_start = PAGE_ALIGN((unsigned int) &_end);

        printk(KERN_INFO "Memory Start=%08lx, Memory End=%08lx\n",
               memory_start, memory_end);

#ifdef CONFIG_BLK_DEV_INITRD
        /*
         * Reserve initrd memory if in kernel memory.
         */
        if (initrd_start < initrd_end)
                if (memblock_is_region_memory(initrd_start,
                                              initrd_end - initrd_start))
                        memblock_reserve(initrd_start,
                                         initrd_end - initrd_start);
#endif

        init_mm.start_code = (unsigned long) &_stext;
        init_mm.end_code   = (unsigned long) &_etext;
        init_mm.end_data   = memory_start;
        init_mm.brk        = memory_start;

        /*
         * Give all the memory to the bootmap allocator,  tell it to put the
         * boot mem_map at the start of memory
         */
        bootmap_size = init_bootmem_node(NODE_DATA(0),
                                         memory_start >> PAGE_SHIFT,
                                         PAGE_OFFSET >> PAGE_SHIFT,
                                         memory_end >> PAGE_SHIFT);
        memblock_reserve(memory_start, bootmap_size);

        unflatten_device_tree();

        c6x_cache_init();

        /* Set the whole external memory as non-cacheable */
        disable_caching(ram_start, ram_end - 1);

        /* Set caching of external RAM used by Linux */
        for_each_memblock(memory, reg)
                enable_caching(CACHE_REGION_START(reg->base),
                               CACHE_REGION_START(reg->base + reg->size - 1));

#ifdef CONFIG_BLK_DEV_INITRD
        /*
         * Enable caching for initrd which falls outside kernel memory.
         */
        if (initrd_start < initrd_end) {
                if (!memblock_is_region_memory(initrd_start,
                                               initrd_end - initrd_start))
                        enable_caching(CACHE_REGION_START(initrd_start),
                                       CACHE_REGION_START(initrd_end - 1));
        }
#endif

        /*
         * Disable caching for dma coherent memory taken from kernel memory.
         */
        if (dma_size && memblock_is_region_memory(dma_start, dma_size))
                disable_caching(dma_start,
                                CACHE_REGION_START(dma_start + dma_size - 1));

        /* Initialize the coherent memory allocator */
        coherent_mem_init(dma_start, dma_size);

        /*
         * Free all memory as a starting point.
         */
        free_bootmem(PAGE_OFFSET, memory_end - PAGE_OFFSET);

        /*
         * Then reserve memory which is already being used.
         */
        for_each_memblock(reserved, reg) {
                pr_debug("reserved - 0x%08x-0x%08x\n",
                         (u32) reg->base, (u32) reg->size);
                reserve_bootmem(reg->base, reg->size, BOOTMEM_DEFAULT);
        }

        max_low_pfn = PFN_DOWN(memory_end);
        min_low_pfn = PFN_UP(memory_start);
        max_mapnr = max_low_pfn - min_low_pfn;

        /* Get kmalloc into gear */
        paging_init();

        /*
         * Probe for Device State Configuration Registers.
         * We have to do this early in case timer needs to be enabled
         * through DSCR.
         */
        dscr_probe();

        /* We do this early for timer and core clock frequency */
        c64x_setup_clocks();

        /* Get CPU info */
        get_cpuinfo();

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

#define cpu_to_ptr(n) ((void *)((long)(n)+1))
#define ptr_to_cpu(p) ((long)(p) - 1)

static int show_cpuinfo(struct seq_file *m, void *v)
{
        int n = ptr_to_cpu(v);
        struct cpuinfo_c6x *p = &per_cpu(cpu_data, n);

        if (n == 0) {
                seq_printf(m,
                           "soc\t\t: %s\n"
                           "soc revision\t: 0x%x\n"
                           "soc cores\t: %d\n",
                           c6x_soc_name, c6x_silicon_rev, c6x_num_cores);
        }

        seq_printf(m,
                   "\n"
                   "processor\t: %d\n"
                   "cpu\t\t: %s\n"
                   "core revision\t: %s\n"
                   "core voltage\t: %s\n"
                   "core id\t\t: %d\n"
                   "mmu\t\t: %s\n"
                   "fpu\t\t: %s\n"
                   "cpu MHz\t\t: %u\n"
                   "bogomips\t: %lu.%02lu\n\n",
                   n,
                   p->cpu_name, p->cpu_rev, p->cpu_voltage,
                   p->core_id, p->mmu, p->fpu,
                   (c6x_core_freq + 500000) / 1000000,
                   (loops_per_jiffy/(500000/HZ)),
                   (loops_per_jiffy/(5000/HZ))%100);

        return 0;
}

static void *c_start(struct seq_file *m, loff_t *pos)
{
        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 NULL;
}
static void c_stop(struct seq_file *m, void *v)
{
}

const struct seq_operations cpuinfo_op = {
        c_start,
        c_stop,
        c_next,
        show_cpuinfo
};

static struct cpu cpu_devices[NR_CPUS];

static int __init topology_init(void)
{
        int i;

        for_each_present_cpu(i)
                register_cpu(&cpu_devices[i], i);

        return 0;
}

subsys_initcall(topology_init);