/*
 * Copyright (C) 1996 David S. Miller (dm@engr.sgi.com)
 * Copyright (C) 1997, 2001 Ralf Baechle (ralf@gnu.org)
 * Copyright (C) 2000 SiByte, Inc.
 * Copyright (C) 2002, 2003 Broadcom Corporation
 *
 * Written by Justin Carlson of SiByte, Inc.
 *         and Kip Walker of Broadcom Corp.
 *
 *
 * 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; either version 2
 * of the License, or (at your option) any later version.
 *
 * 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.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 */

#include <linux/config.h>
#include <linux/sched.h>
#include <linux/smp.h>

#include <asm/io.h>
#include <asm/sibyte/sb1250.h>
#include <asm/sibyte/sb1250_regs.h>
#include <asm/sibyte/sb1250_dma.h>
#include <asm/sibyte/64bit.h>

#ifdef CONFIG_SB1_PASS_1_WORKAROUNDS
#define SB1_PREF_LOAD_STREAMED_HINT "0"
#define SB1_PREF_STORE_STREAMED_HINT "1"
#else
#define SB1_PREF_LOAD_STREAMED_HINT "4"
#define SB1_PREF_STORE_STREAMED_HINT "5"
#endif

#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
static inline void clear_page_cpu(void *page)
#else
void clear_page(void *page)
#endif
{
        /*
         * JDCXXX - This should be bottlenecked by the write buffer, but these
         * things tend to be mildly unpredictable...should check this on the
         * performance model
         *
         * We prefetch 4 lines ahead.  We're also "cheating" slightly here...
         * since we know we're on an SB1, we force the assembler to take
         * 64-bit operands to speed things up
         */
        __asm__ __volatile__(
                ".set push                  \n"
                ".set noreorder             \n"
                ".set noat                  \n"
                ".set mips4                 \n"
                "     addiu     $1, %0, %2  \n"  /* Calculate the end of the page to clear */
#ifdef CONFIG_CPU_HAS_PREFETCH
                "     pref       " SB1_PREF_STORE_STREAMED_HINT ",  0(%0)  \n"  /* Prefetch the first 4 lines */
                "     pref       " SB1_PREF_STORE_STREAMED_HINT ", 32(%0)  \n"
                "     pref       " SB1_PREF_STORE_STREAMED_HINT ", 64(%0)  \n"
                "     pref       " SB1_PREF_STORE_STREAMED_HINT ", 96(%0)  \n"
#endif
                "1:   sd        $0,  0(%0)  \n"  /* Throw out a cacheline of 0's */
                "     sd        $0,  8(%0)  \n"
                "     sd        $0, 16(%0)  \n"
                "     sd        $0, 24(%0)  \n"
#ifdef CONFIG_CPU_HAS_PREFETCH
                "     pref       " SB1_PREF_STORE_STREAMED_HINT ",128(%0)  \n"  /* Prefetch 4 lines ahead     */
#endif
                "     bne       $1, %0, 1b  \n"
                "     addiu     %0, %0, 32  \n"  /* Next cacheline (This instruction better be short piped!) */
                ".set pop                   \n"
                : "=r" (page)
                : "0" (page), "I" (PAGE_SIZE-32)
                : "memory");

}

#ifdef CONFIG_SIBYTE_DMA_PAGEOPS
static inline void copy_page_cpu(void *to, void *from)
#else
void copy_page(void *to, void *from)
#endif
{
        /*
         * This should be optimized in assembly...can't use ld/sd, though,
         * because the top 32 bits could be nuked if we took an interrupt
         * during the routine.  And this is not a good place to be cli()'ing
         *
         * The pref's used here are using "streaming" hints, which cause the
         * copied data to be kicked out of the cache sooner.  A page copy often
         * ends up copying a lot more data than is commonly used, so this seems
         * to make sense in terms of reducing cache pollution, but I've no real
         * performance data to back this up
         */

        __asm__ __volatile__(
                ".set push                  \n"
                ".set noreorder             \n"
                ".set noat                  \n"
                ".set mips4                 \n"
                "     addiu     $1, %0, %4  \n"  /* Calculate the end of the page to copy */
#ifdef CONFIG_CPU_HAS_PREFETCH
                "     pref       " SB1_PREF_LOAD_STREAMED_HINT  ",  0(%0)  \n"  /* Prefetch the first 3 lines */
                "     pref       " SB1_PREF_STORE_STREAMED_HINT ",  0(%1)  \n"
                "     pref       " SB1_PREF_LOAD_STREAMED_HINT  ",  32(%0) \n"
                "     pref       " SB1_PREF_STORE_STREAMED_HINT ",  32(%1) \n"
                "     pref       " SB1_PREF_LOAD_STREAMED_HINT  ",  64(%0) \n"
                "     pref       " SB1_PREF_STORE_STREAMED_HINT ",  64(%1) \n"
#endif
                "1:   lw        $2,  0(%0)  \n"  /* Block copy a cacheline */
                "     lw        $3,  4(%0)  \n"
                "     lw        $4,  8(%0)  \n"
                "     lw        $5, 12(%0)  \n"
                "     lw        $6, 16(%0)  \n"
                "     lw        $7, 20(%0)  \n"
                "     lw        $8, 24(%0)  \n"
                "     lw        $9, 28(%0)  \n"
#ifdef CONFIG_CPU_HAS_PREFETCH
                "     pref       " SB1_PREF_LOAD_STREAMED_HINT  ", 96(%0)  \n"  /* Prefetch ahead         */
                "     pref       " SB1_PREF_STORE_STREAMED_HINT ", 96(%1)  \n"
#endif
                "     sw        $2,  0(%1)  \n"
                "     sw        $3,  4(%1)  \n"
                "     sw        $4,  8(%1)  \n"
                "     sw        $5, 12(%1)  \n"
                "     sw        $6, 16(%1)  \n"
                "     sw        $7, 20(%1)  \n"
                "     sw        $8, 24(%1)  \n"
                "     sw        $9, 28(%1)  \n"
                "     addiu     %1, %1, 32  \n"  /* Next cacheline */
                "     nop                   \n"  /* Force next add to short pipe */
                "     nop                   \n"  /* Force next add to short pipe */
                "     bne       $1, %0, 1b  \n"
                "     addiu     %0, %0, 32  \n"  /* Next cacheline */
                ".set pop                   \n"
                : "=r" (to), "=r" (from)
                : "0" (from), "1" (to), "I" (PAGE_SIZE-32)
                : "$2","$3","$4","$5","$6","$7","$8","$9","memory");
}


#ifdef CONFIG_SIBYTE_DMA_PAGEOPS

/*
 * Pad descriptors to cacheline, since each is exclusively owned by a
 * particular CPU. 
 */
typedef struct dmadscr_s {
        uint64_t  dscr_a;
        uint64_t  dscr_b;
        uint64_t  pad_a;
        uint64_t  pad_b;
} dmadscr_t;

static dmadscr_t page_descr[NR_CPUS] __attribute__((aligned(SMP_CACHE_BYTES)));

void sb1_dma_init(void)
{
        int cpu = smp_processor_id();
        uint64_t base_val = PHYSADDR(&page_descr[cpu]) | V_DM_DSCR_BASE_RINGSZ(1);

        out64(base_val,
              IO_SPACE_BASE + A_DM_REGISTER(cpu, R_DM_DSCR_BASE));
        out64(base_val | M_DM_DSCR_BASE_RESET,
              IO_SPACE_BASE + A_DM_REGISTER(cpu, R_DM_DSCR_BASE));
        out64(base_val | M_DM_DSCR_BASE_ENABL,
              IO_SPACE_BASE + A_DM_REGISTER(cpu, R_DM_DSCR_BASE));
}

void clear_page(void *page)
{
        int cpu = smp_processor_id();

        /* if the page is above Kseg0, use old way */
        if (KSEGX(page) != K0BASE)
                return clear_page_cpu(page);

        page_descr[cpu].dscr_a = PHYSADDR(page) | M_DM_DSCRA_ZERO_MEM | M_DM_DSCRA_L2C_DEST | M_DM_DSCRA_INTERRUPT;
        page_descr[cpu].dscr_b = V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
        out64(1, IO_SPACE_BASE + A_DM_REGISTER(cpu, R_DM_DSCR_COUNT));

        /*
         * Don't really want to do it this way, but there's no
         * reliable way to delay completion detection.
         */
        while (!(in64(IO_SPACE_BASE + A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)) & M_DM_DSCR_BASE_INTERRUPT))
                ;
        in64(IO_SPACE_BASE + A_DM_REGISTER(cpu, R_DM_DSCR_BASE));
}

void copy_page(void *to, void *from)
{
        unsigned long from_phys = PHYSADDR(from);
        unsigned long to_phys = PHYSADDR(to);
        int cpu = smp_processor_id();

        /* if either page is above Kseg0, use old way */
        if ((KSEGX(to) != K0BASE) || (KSEGX(from) != K0BASE))
                return copy_page_cpu(to, from);

        page_descr[cpu].dscr_a = PHYSADDR(to_phys) | M_DM_DSCRA_L2C_DEST | M_DM_DSCRA_INTERRUPT;
        page_descr[cpu].dscr_b = PHYSADDR(from_phys) | V_DM_DSCRB_SRC_LENGTH(PAGE_SIZE);
        out64(1, IO_SPACE_BASE + A_DM_REGISTER(cpu, R_DM_DSCR_COUNT));

        /*
         * Don't really want to do it this way, but there's no
         * reliable way to delay completion detection.
         */
        while (!(in64(IO_SPACE_BASE + A_DM_REGISTER(cpu, R_DM_DSCR_BASE_DEBUG)) & M_DM_DSCR_BASE_INTERRUPT))
                ;
        in64(IO_SPACE_BASE + A_DM_REGISTER(cpu, R_DM_DSCR_BASE));
}

#endif /* CONFIG_SIBYTE_DMA_PAGEOPS */