127 lines
2.8 KiB
C
127 lines
2.8 KiB
C
/* tadpole.c: Probing for the tadpole clock stopping h/w at boot time.
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*
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* Copyright (C) 1996 David Redman (djhr@tadpole.co.uk)
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*/
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#include <linux/string.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/init.h>
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#include <asm/asi.h>
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#include <asm/oplib.h>
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#include <asm/io.h>
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#define MACIO_SCSI_CSR_ADDR 0x78400000
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#define MACIO_EN_DMA 0x00000200
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#define CLOCK_INIT_DONE 1
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static int clk_state;
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static volatile unsigned char *clk_ctrl;
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void (*cpu_pwr_save)(void);
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static inline unsigned int ldphys(unsigned int addr)
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{
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unsigned long data;
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__asm__ __volatile__("\n\tlda [%1] %2, %0\n\t" :
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"=r" (data) :
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"r" (addr), "i" (ASI_M_BYPASS));
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return data;
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}
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static void clk_init(void)
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{
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__asm__ __volatile__("mov 0x6c, %%g1\n\t"
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"mov 0x4c, %%g2\n\t"
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"mov 0xdf, %%g3\n\t"
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"stb %%g1, [%0+3]\n\t"
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"stb %%g2, [%0+3]\n\t"
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"stb %%g3, [%0+3]\n\t" : :
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"r" (clk_ctrl) :
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"g1", "g2", "g3");
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}
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static void clk_slow(void)
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{
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__asm__ __volatile__("mov 0xcc, %%g2\n\t"
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"mov 0x4c, %%g3\n\t"
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"mov 0xcf, %%g4\n\t"
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"mov 0xdf, %%g5\n\t"
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"stb %%g2, [%0+3]\n\t"
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"stb %%g3, [%0+3]\n\t"
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"stb %%g4, [%0+3]\n\t"
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"stb %%g5, [%0+3]\n\t" : :
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"r" (clk_ctrl) :
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"g2", "g3", "g4", "g5");
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}
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/*
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* Tadpole is guaranteed to be UP, using local_irq_save.
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*/
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static void tsu_clockstop(void)
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{
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unsigned int mcsr;
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unsigned long flags;
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if (!clk_ctrl)
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return;
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if (!(clk_state & CLOCK_INIT_DONE)) {
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local_irq_save(flags);
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clk_init();
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clk_state |= CLOCK_INIT_DONE; /* all done */
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local_irq_restore(flags);
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return;
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}
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if (!(clk_ctrl[2] & 1))
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return; /* no speed up yet */
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local_irq_save(flags);
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/* if SCSI DMA in progress, don't slow clock */
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mcsr = ldphys(MACIO_SCSI_CSR_ADDR);
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if ((mcsr&MACIO_EN_DMA) != 0) {
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local_irq_restore(flags);
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return;
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}
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/* TODO... the minimum clock setting ought to increase the
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* memory refresh interval..
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*/
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clk_slow();
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local_irq_restore(flags);
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}
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static void swift_clockstop(void)
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{
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if (!clk_ctrl)
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return;
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clk_ctrl[0] = 0;
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}
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void __init clock_stop_probe(void)
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{
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unsigned int node, clk_nd;
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char name[20];
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prom_getstring(prom_root_node, "name", name, sizeof(name));
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if (strncmp(name, "Tadpole", 7))
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return;
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node = prom_getchild(prom_root_node);
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node = prom_searchsiblings(node, "obio");
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node = prom_getchild(node);
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clk_nd = prom_searchsiblings(node, "clk-ctrl");
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if (!clk_nd)
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return;
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printk("Clock Stopping h/w detected... ");
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clk_ctrl = (char *) prom_getint(clk_nd, "address");
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clk_state = 0;
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if (name[10] == '\0') {
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cpu_pwr_save = tsu_clockstop;
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printk("enabled (S3)\n");
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} else if ((name[10] == 'X') || (name[10] == 'G')) {
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cpu_pwr_save = swift_clockstop;
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printk("enabled (%s)\n",name+7);
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} else
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printk("disabled %s\n",name+7);
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}
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