1 files changed, 126 insertions, 0 deletions
diff --git a/arch/sparc/kernel/tadpole.c b/arch/sparc/kernel/tadpole.c
new file mode 100644
index 0000000..f476a5f
--- /dev/null
+++ b/arch/sparc/kernel/tadpole.c
@@ -0,0 +1,126 @@
+/* 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 <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/init.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");
+}
+
+/*
+ * Tadpole is guaranteed to be UP, using local_irq_save.
+ */
+static void tsu_clockstop(void)
+{
+	unsigned int mcsr;
+	unsigned long flags;
+
+	if (!clk_ctrl)
+		return;
+	if (!(clk_state & CLOCK_INIT_DONE)) {
+		local_irq_save(flags);
+		clk_init();
+		clk_state |= CLOCK_INIT_DONE;       /* all done */
+		local_irq_restore(flags);
+		return;
+	}
+	if (!(clk_ctrl[2] & 1))
+		return;               /* no speed up yet */
+
+	local_irq_save(flags);
+
+	/* if SCSI DMA in progress, don't slow clock */
+	mcsr = ldphys(MACIO_SCSI_CSR_ADDR);
+	if ((mcsr&MACIO_EN_DMA) != 0) {
+		local_irq_restore(flags);
+		return;
+	}
+	/* TODO... the minimum clock setting ought to increase the
+	 * memory refresh interval..
+	 */
+	clk_slow();
+	local_irq_restore(flags);
+}
+
+static void swift_clockstop(void)
+{
+	if (!clk_ctrl)
+		return;
+	clk_ctrl[0] = 0;
+}
+
+void __init 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);
+}