patch-2.3.16 linux/arch/ppc/kernel/gemini_prom.S

• Lines: 96
• Date: Tue Aug 31 11:36:43 1999
• Orig file: v2.3.15/linux/arch/ppc/kernel/gemini_prom.S
• Orig date: Wed Dec 31 16:00:00 1969

diff -u --recursive --new-file v2.3.15/linux/arch/ppc/kernel/gemini_prom.S linux/arch/ppc/kernel/gemini_prom.S
@@ -0,0 +1,95 @@
+/*
+ *  arch/ppc/kernel/gemini_prom.S
+ *
+ *  Not really prom support code (yet), but sort of anti-prom code.  The current
+ *  bootloader does a number of things it shouldn't and doesn't do things that it
+ *  should.  The stuff in here is mainly a hodge-podge collection of setup code
+ *  to get the board up and running.
+ *    ---Dan
+ */
+
+#include "ppc_asm.tmpl"
+#include "ppc_defs.h"
+#include <linux/config.h>
+#include <asm/processor.h>
+#include <asm/page.h>
+#include <asm/gemini.h>
+
+#define HID0_ABE (1<<3)
+
+/*
+ *  On 750's the MMU is on when Linux is booted, so we need to clear out the
+ *  bootloader's BAT settings, make sure we're in supervisor state (gotcha!),
+ *  and turn off the MMU.
+ *
+ */
+
+_GLOBAL(gemini_prom_init)
+#ifdef __SMP__
+	/* Since the MMU's on, get stuff in rom space that we'll need */
+	lis	r4,GEMINI_CPUSTAT@h
+	ori	r4,r4,GEMINI_CPUSTAT@l
+	lbz	r5,0(r4)
+	andi.	r5,r5,3
+	mr	r24,r5		/* cpu # used later on */
+#endif
+	mfmsr	r4
+	li	r3,MSR_PR	/* ensure supervisor! */
+	ori	r3,r3,MSR_IR|MSR_DR
+	andc	r4,r4,r3
+	mtmsr	r4
+#if 0
+	/* zero out the bats now that the MMU is off */
+prom_no_mmu:	
+	li	r3,0
+        mtspr   IBAT0U,r3
+        mtspr   IBAT0L,r3
+        mtspr   IBAT1U,r3
+        mtspr   IBAT1L,r3
+        mtspr   IBAT2U,r3
+        mtspr   IBAT2L,r3
+        mtspr   IBAT3U,r3
+        mtspr   IBAT3L,r3
+
+        mtspr   DBAT0U,r3
+        mtspr   DBAT0L,r3
+        mtspr   DBAT1U,r3
+        mtspr   DBAT1L,r3
+        mtspr   DBAT2U,r3
+	mtspr   DBAT2L,r3
+        mtspr   DBAT3U,r3
+        mtspr   DBAT3L,r3
+#endif
+
+	/* the bootloader (as far as I'm currently aware) doesn't mess with page
+	   tables, but since we're already here, might as well zap these, too */
+	li	r4,0
+	mtspr	SDR1,r4
+
+	li	r4,16
+	mtctr	r4
+	li	r3,0
+	li	r4,0
+3:	mtsrin	r3,r4
+	addi	r3,r3,1
+	bdnz	3b
+
+#ifdef __SMP__
+	/* The 750 book (and Mot/IBM support) says that this will "assist" snooping
+	   when in SMP.  Not sure yet whether this should stay or leave... */
+	mfspr	r4,HID0
+	ori	r4,r4,HID0_ABE
+	mtspr	HID0,r4
+	sync
+#endif /* __SMP__ */
+	blr
+
+/*  apparently, SMon doesn't pay attention to HID0[SRST].  Disable the MMU and
+    branch to 0xfff00100 */
+_GLOBAL(_gemini_reboot)
+	lis	r5,GEMINI_BOOT_INIT@h
+	ori	r5,r5,GEMINI_BOOT_INIT@l
+	li	r6,MSR_IP
+	mtspr	SRR0,r5
+	mtspr	SRR1,r6
+	rfi