/*
 * R-Car Generation 2 support
 *
 * Copyright (C) 2013  Renesas Solutions Corp.
 * Copyright (C) 2013  Magnus Damm
 * Copyright (C) 2014  Ulrich Hecht
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; version 2 of the License.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 */

#include <linux/clk-provider.h>
#include <linux/clocksource.h>
#include <linux/device.h>
#include <linux/dma-contiguous.h>
#include <linux/io.h>
#include <linux/kernel.h>
#include <linux/memblock.h>
#include <linux/of.h>
#include <linux/of_fdt.h>
#include <linux/of_platform.h>
#include <asm/mach/arch.h>
#include "common.h"
#include "rcar-gen2.h"

static unsigned int __init get_extal_freq(void)
{
        struct device_node *cpg, *extal;
        u32 freq = 20000000;

        cpg = of_find_compatible_node(NULL, NULL,
                                      "renesas,rcar-gen2-cpg-clocks");
        if (!cpg)
                return freq;

        extal = of_parse_phandle(cpg, "clocks", 0);
        of_node_put(cpg);
        if (!extal)
                return freq;

        of_property_read_u32(extal, "clock-frequency", &freq);
        of_node_put(extal);
        return freq;
}

#define CNTCR 0
#define CNTFID0 0x20

void __init rcar_gen2_timer_init(void)
{
#ifdef CONFIG_ARM_ARCH_TIMER
        void __iomem *base;
        u32 freq;

        if (of_machine_is_compatible("renesas,r8a7792") ||
            of_machine_is_compatible("renesas,r8a7794")) {
                freq = 260000000 / 8;   /* ZS / 8 */
                /* CNTVOFF has to be initialized either from non-secure
                 * Hypervisor mode or secure Monitor mode with SCR.NS==1.
                 * If TrustZone is enabled then it should be handled by the
                 * secure code.
                 */
                asm volatile(
                "       cps     0x16\n"
                "       mrc     p15, 0, r1, c1, c1, 0\n"
                "       orr     r0, r1, #1\n"
                "       mcr     p15, 0, r0, c1, c1, 0\n"
                "       isb\n"
                "       mov     r0, #0\n"
                "       mcrr    p15, 4, r0, r0, c14\n"
                "       isb\n"
                "       mcr     p15, 0, r1, c1, c1, 0\n"
                "       isb\n"
                "       cps     0x13\n"
                        : : : "r0", "r1");
        } else {
                /* At Linux boot time the r8a7790 arch timer comes up
                 * with the counter disabled. Moreover, it may also report
                 * a potentially incorrect fixed 13 MHz frequency. To be
                 * correct these registers need to be updated to use the
                 * frequency EXTAL / 2.
                 */
                freq = get_extal_freq() / 2;
        }

        /* Remap "armgcnt address map" space */
        base = ioremap(0xe6080000, PAGE_SIZE);

        /*
         * Update the timer if it is either not running, or is not at the
         * right frequency. The timer is only configurable in secure mode
         * so this avoids an abort if the loader started the timer and
         * entered the kernel in non-secure mode.
         */

        if ((ioread32(base + CNTCR) & 1) == 0 ||
            ioread32(base + CNTFID0) != freq) {
                /* Update registers with correct frequency */
                iowrite32(freq, base + CNTFID0);
                asm volatile("mcr p15, 0, %0, c14, c0, 0" : : "r" (freq));

                /* make sure arch timer is started by setting bit 0 of CNTCR */
                iowrite32(1, base + CNTCR);
        }

        iounmap(base);
#endif /* CONFIG_ARM_ARCH_TIMER */

        of_clk_init(NULL);
        clocksource_probe();
}

struct memory_reserve_config {
        u64 reserved;
        u64 base, size;
};

static int __init rcar_gen2_scan_mem(unsigned long node, const char *uname,
                                     int depth, void *data)
{
        const char *type = of_get_flat_dt_prop(node, "device_type", NULL);
        const __be32 *reg, *endp;
        int l;
        struct memory_reserve_config *mrc = data;
        u64 lpae_start = 1ULL << 32;

        /* We are scanning "memory" nodes only */
        if (type == NULL || strcmp(type, "memory"))
                return 0;

        reg = of_get_flat_dt_prop(node, "linux,usable-memory", &l);
        if (reg == NULL)
                reg = of_get_flat_dt_prop(node, "reg", &l);
        if (reg == NULL)
                return 0;

        endp = reg + (l / sizeof(__be32));
        while ((endp - reg) >= (dt_root_addr_cells + dt_root_size_cells)) {
                u64 base, size;

                base = dt_mem_next_cell(dt_root_addr_cells, &reg);
                size = dt_mem_next_cell(dt_root_size_cells, &reg);

                if (base >= lpae_start)
                        continue;

                if ((base + size) >= lpae_start)
                        size = lpae_start - base;

                if (size < mrc->reserved)
                        continue;

                if (base < mrc->base)
                        continue;

                /* keep the area at top near the 32-bit legacy limit */
                mrc->base = base + size - mrc->reserved;
                mrc->size = mrc->reserved;
        }

        return 0;
}

void __init rcar_gen2_reserve(void)
{
        struct memory_reserve_config mrc;

        /* reserve 256 MiB at the top of the physical legacy 32-bit space */
        memset(&mrc, 0, sizeof(mrc));
        mrc.reserved = SZ_256M;

        of_scan_flat_dt(rcar_gen2_scan_mem, &mrc);
#ifdef CONFIG_DMA_CMA
        if (mrc.size && memblock_is_region_memory(mrc.base, mrc.size)) {
                static struct cma *rcar_gen2_dma_contiguous;

                dma_contiguous_reserve_area(mrc.size, mrc.base, 0,
                                            &rcar_gen2_dma_contiguous, true);
        }
#endif
}

static const char * const rcar_gen2_boards_compat_dt[] __initconst = {
        /*
         * R8A7790 and R8A7791 can't be handled here as long as they need SMP
         * initialization fallback.
         */
        "renesas,r8a7792",
        "renesas,r8a7793",
        "renesas,r8a7794",
        NULL,
};

DT_MACHINE_START(RCAR_GEN2_DT, "Generic R-Car Gen2 (Flattened Device Tree)")
        .init_early     = shmobile_init_delay,
        .init_late      = shmobile_init_late,
        .init_time      = rcar_gen2_timer_init,
        .reserve        = rcar_gen2_reserve,
        .dt_compat      = rcar_gen2_boards_compat_dt,
MACHINE_END

static const char * const rz_g1_boards_compat_dt[] __initconst = {
        "renesas,r8a7743",
        "renesas,r8a7745",
        NULL,
};

DT_MACHINE_START(RZ_G1_DT, "Generic RZ/G1 (Flattened Device Tree)")
        .init_early     = shmobile_init_delay,
        .init_late      = shmobile_init_late,
        .init_time      = rcar_gen2_timer_init,
        .reserve        = rcar_gen2_reserve,
        .dt_compat      = rz_g1_boards_compat_dt,
MACHINE_END