/*
 * arch/arm/mm/cache-tauros2.c - Tauros2 L2 cache controller support
 *
 * Copyright (C) 2008 Marvell Semiconductor
 *
 * This file is licensed under the terms of the GNU General Public
 * License version 2.  This program is licensed "as is" without any
 * warranty of any kind, whether express or implied.
 *
 * References:
 * - PJ1 CPU Core Datasheet,
 *   Document ID MV-S104837-01, Rev 0.7, January 24 2008.
 * - PJ4 CPU Core Datasheet,
 *   Document ID MV-S105190-00, Rev 0.7, March 14 2008.
 */

#include <linux/init.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <asm/cacheflush.h>
#include <asm/cp15.h>
#include <asm/cputype.h>
#include <asm/hardware/cache-tauros2.h>

/* CP15 PJ4 Control configuration register */
#define CCR_L2C_PREFETCH_DISABLE        BIT(24)
#define CCR_L2C_ECC_ENABLE              BIT(23)
#define CCR_L2C_WAY7_4_DISABLE          BIT(21)
#define CCR_L2C_BURST8_ENABLE           BIT(20)

/*
 * When Tauros2 is used on a CPU that supports the v7 hierarchical
 * cache operations, the cache handling code in proc-v7.S takes care
 * of everything, including handling DMA coherency.
 *
 * So, we only need to register outer cache operations here if we're
 * being used on a pre-v7 CPU, and we only need to build support for
 * outer cache operations into the kernel image if the kernel has been
 * configured to support a pre-v7 CPU.
 */
#ifdef CONFIG_CPU_32v5
/*
 * Low-level cache maintenance operations.
 */
static inline void tauros2_clean_pa(unsigned long addr)
{
        __asm__("mcr p15, 1, %0, c7, c11, 3" : : "r" (addr));
}

static inline void tauros2_clean_inv_pa(unsigned long addr)
{
        __asm__("mcr p15, 1, %0, c7, c15, 3" : : "r" (addr));
}

static inline void tauros2_inv_pa(unsigned long addr)
{
        __asm__("mcr p15, 1, %0, c7, c7, 3" : : "r" (addr));
}


/*
 * Linux primitives.
 *
 * Note that the end addresses passed to Linux primitives are
 * noninclusive.
 */
#define CACHE_LINE_SIZE         32

static void tauros2_inv_range(unsigned long start, unsigned long end)
{
        /*
         * Clean and invalidate partial first cache line.
         */
        if (start & (CACHE_LINE_SIZE - 1)) {
                tauros2_clean_inv_pa(start & ~(CACHE_LINE_SIZE - 1));
                start = (start | (CACHE_LINE_SIZE - 1)) + 1;
        }

        /*
         * Clean and invalidate partial last cache line.
         */
        if (end & (CACHE_LINE_SIZE - 1)) {
                tauros2_clean_inv_pa(end & ~(CACHE_LINE_SIZE - 1));
                end &= ~(CACHE_LINE_SIZE - 1);
        }

        /*
         * Invalidate all full cache lines between 'start' and 'end'.
         */
        while (start < end) {
                tauros2_inv_pa(start);
                start += CACHE_LINE_SIZE;
        }

        dsb();
}

static void tauros2_clean_range(unsigned long start, unsigned long end)
{
        start &= ~(CACHE_LINE_SIZE - 1);
        while (start < end) {
                tauros2_clean_pa(start);
                start += CACHE_LINE_SIZE;
        }

        dsb();
}

static void tauros2_flush_range(unsigned long start, unsigned long end)
{
        start &= ~(CACHE_LINE_SIZE - 1);
        while (start < end) {
                tauros2_clean_inv_pa(start);
                start += CACHE_LINE_SIZE;
        }

        dsb();
}

static void tauros2_disable(void)
{
        __asm__ __volatile__ (
        "mcr    p15, 1, %0, c7, c11, 0 @L2 Cache Clean All\n\t"
        "mrc    p15, 0, %0, c1, c0, 0\n\t"
        "bic    %0, %0, #(1 << 26)\n\t"
        "mcr    p15, 0, %0, c1, c0, 0  @Disable L2 Cache\n\t"
        : : "r" (0x0));
}

static void tauros2_resume(void)
{
        __asm__ __volatile__ (
        "mcr    p15, 1, %0, c7, c7, 0 @L2 Cache Invalidate All\n\t"
        "mrc    p15, 0, %0, c1, c0, 0\n\t"
        "orr    %0, %0, #(1 << 26)\n\t"
        "mcr    p15, 0, %0, c1, c0, 0 @Enable L2 Cache\n\t"
        : : "r" (0x0));
}
#endif

static inline u32 __init read_extra_features(void)
{
        u32 u;

        __asm__("mrc p15, 1, %0, c15, c1, 0" : "=r" (u));

        return u;
}

static inline void __init write_extra_features(u32 u)
{
        __asm__("mcr p15, 1, %0, c15, c1, 0" : : "r" (u));
}

static inline int __init cpuid_scheme(void)
{
        return !!((processor_id & 0x000f0000) == 0x000f0000);
}

static inline u32 __init read_mmfr3(void)
{
        u32 mmfr3;

        __asm__("mrc p15, 0, %0, c0, c1, 7\n" : "=r" (mmfr3));

        return mmfr3;
}

static inline u32 __init read_actlr(void)
{
        u32 actlr;

        __asm__("mrc p15, 0, %0, c1, c0, 1\n" : "=r" (actlr));

        return actlr;
}

static inline void __init write_actlr(u32 actlr)
{
        __asm__("mcr p15, 0, %0, c1, c0, 1\n" : : "r" (actlr));
}

static void enable_extra_feature(unsigned int features)
{
        u32 u;

        u = read_extra_features();

        if (features & CACHE_TAUROS2_PREFETCH_ON)
                u &= ~CCR_L2C_PREFETCH_DISABLE;
        else
                u |= CCR_L2C_PREFETCH_DISABLE;
        pr_info("Tauros2: %s L2 prefetch.\n",
                        (features & CACHE_TAUROS2_PREFETCH_ON)
                        ? "Enabling" : "Disabling");

        if (features & CACHE_TAUROS2_LINEFILL_BURST8)
                u |= CCR_L2C_BURST8_ENABLE;
        else
                u &= ~CCR_L2C_BURST8_ENABLE;
        pr_info("Tauros2: %s burst8 line fill.\n",
                        (features & CACHE_TAUROS2_LINEFILL_BURST8)
                        ? "Enabling" : "Disabling");

        write_extra_features(u);
}

static void __init tauros2_internal_init(unsigned int features)
{
        char *mode = NULL;

        enable_extra_feature(features);

#ifdef CONFIG_CPU_32v5
        if ((processor_id & 0xff0f0000) == 0x56050000) {
                u32 feat;

                /*
                 * v5 CPUs with Tauros2 have the L2 cache enable bit
                 * located in the CPU Extra Features register.
                 */
                feat = read_extra_features();
                if (!(feat & 0x00400000)) {
                        pr_info("Tauros2: Enabling L2 cache.\n");
                        write_extra_features(feat | 0x00400000);
                }

                mode = "ARMv5";
                outer_cache.inv_range = tauros2_inv_range;
                outer_cache.clean_range = tauros2_clean_range;
                outer_cache.flush_range = tauros2_flush_range;
                outer_cache.disable = tauros2_disable;
                outer_cache.resume = tauros2_resume;
        }
#endif

#ifdef CONFIG_CPU_32v7
        /*
         * Check whether this CPU has support for the v7 hierarchical
         * cache ops.  (PJ4 is in its v7 personality mode if the MMFR3
         * register indicates support for the v7 hierarchical cache
         * ops.)
         *
         * (Although strictly speaking there may exist CPUs that
         * implement the v7 cache ops but are only ARMv6 CPUs (due to
         * not complying with all of the other ARMv7 requirements),
         * there are no real-life examples of Tauros2 being used on
         * such CPUs as of yet.)
         */
        if (cpuid_scheme() && (read_mmfr3() & 0xf) == 1) {
                u32 actlr;

                /*
                 * When Tauros2 is used in an ARMv7 system, the L2
                 * enable bit is located in the Auxiliary System Control
                 * Register (which is the only register allowed by the
                 * ARMv7 spec to contain fine-grained cache control bits).
                 */
                actlr = read_actlr();
                if (!(actlr & 0x00000002)) {
                        pr_info("Tauros2: Enabling L2 cache.\n");
                        write_actlr(actlr | 0x00000002);
                }

                mode = "ARMv7";
        }
#endif

        if (mode == NULL) {
                pr_crit("Tauros2: Unable to detect CPU mode.\n");
                return;
        }

        pr_info("Tauros2: L2 cache support initialised "
                         "in %s mode.\n", mode);
}

#ifdef CONFIG_OF
static const struct of_device_id tauros2_ids[] __initconst = {
        { .compatible = "marvell,tauros2-cache"},
        {}
};
#endif

void __init tauros2_init(unsigned int features)
{
#ifdef CONFIG_OF
        struct device_node *node;
        int ret;
        unsigned int f;

        node = of_find_matching_node(NULL, tauros2_ids);
        if (!node) {
                pr_info("Not found marvell,tauros2-cache, disable it\n");
        } else {
                ret = of_property_read_u32(node, "marvell,tauros2-cache-features", &f);
                if (ret) {
                        pr_info("Not found marvell,tauros-cache-features property, "
                                "disable extra features\n");
                        features = 0;
                } else
                        features = f;
        }
#endif
        tauros2_internal_init(features);
}