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/* tadpole.c: Probing for the tadpole clock stopping h/w at boot time.

 *

 * Copyright (C) 1996 David Redman (djhr@tadpole.co.uk)

 */

#include <linux/string.h>

#include <asm/asi.h>

#include <asm/oplib.h>

#include <asm/io.h>

#define MACIO_SCSI_CSR_ADDR     0x78400000

#define MACIO_EN_DMA            0x00000200

#define CLOCK_INIT_DONE         1

static int clk_state;

static volatile unsigned char *clk_ctrl;

void (*cpu_pwr_save)(void);

static inline unsigned int ldphys(unsigned int addr)

{

        unsigned long data;

        __asm__ __volatile__("\n\tlda [%1] %2, %0\n\t" :

                             "=r" (data) :

                             "r" (addr), "i" (ASI_M_BYPASS));

        return data;

}

static void clk_init(void)

{

        __asm__ __volatile__("mov 0x6c, %%g1\n\t"

                             "mov 0x4c, %%g2\n\t"

                             "mov 0xdf, %%g3\n\t"

                             "stb %%g1, [%0+3]\n\t"

                             "stb %%g2, [%0+3]\n\t"

                             "stb %%g3, [%0+3]\n\t" : :

                             "r" (clk_ctrl) :

                             "g1", "g2", "g3");

}

static void clk_slow(void)

{

        __asm__ __volatile__("mov 0xcc, %%g2\n\t"

                             "mov 0x4c, %%g3\n\t"

                             "mov 0xcf, %%g4\n\t"

                             "mov 0xdf, %%g5\n\t"

                             "stb %%g2, [%0+3]\n\t"

                             "stb %%g3, [%0+3]\n\t"

                             "stb %%g4, [%0+3]\n\t"

                             "stb %%g5, [%0+3]\n\t" : :

                             "r" (clk_ctrl) :

                             "g2", "g3", "g4", "g5");

}

static void tsu_clockstop(void)

{

        unsigned int mcsr;

        unsigned long flags;

        if (!clk_ctrl)

                return;

        if (!(clk_state & CLOCK_INIT_DONE)) {

                save_flags(flags); cli();

                clk_init();

                clk_state |= CLOCK_INIT_DONE;       /* all done */

                restore_flags(flags);

                return;

        }

        if (!(clk_ctrl[2] & 1))

                return;               /* no speed up yet */

        save_flags(flags); cli();

        /* if SCSI DMA in progress, don't slow clock */

        mcsr = ldphys(MACIO_SCSI_CSR_ADDR);

        if ((mcsr&MACIO_EN_DMA) != 0) {

                restore_flags(flags);

                return;

        }

        /* TODO... the minimum clock setting ought to increase the

         * memory refresh interval..

         */

        clk_slow();

        restore_flags(flags);

}

static void swift_clockstop(void)

{

        if (!clk_ctrl)

                return;

        clk_ctrl[0] = 0;

}

void clock_stop_probe(void)

{

        unsigned int node, clk_nd;

        char name[20];

        prom_getstring(prom_root_node, "name", name, sizeof(name));

        if (strncmp(name, "Tadpole", 7))

                return;

        node = prom_getchild(prom_root_node);

        node = prom_searchsiblings(node, "obio");

        node = prom_getchild(node);

        clk_nd = prom_searchsiblings(node, "clk-ctrl");

        if (!clk_nd)

                return;

        printk("Clock Stopping h/w detected... ");

        clk_ctrl = (char *) prom_getint(clk_nd, "address");

        clk_state = 0;

        if (name[10] == '\0') {

                cpu_pwr_save = tsu_clockstop;

                printk("enabled (S3)\n");

        } else if ((name[10] == 'X') || (name[10] == 'G')) {

                cpu_pwr_save = swift_clockstop;

                printk("enabled (%s)\n",name+7);

        } else

                printk("disabled %s\n",name+7);

}