1 /*
2  * Setup the right wbflush routine for the different DECstations.
3  *
4  * Created with information from:
5  *	DECstation 3100 Desktop Workstation Functional Specification
6  *	DECstation 5000/200 KN02 System Module Functional Specification
7  *	mipsel-linux-objdump --disassemble vmunix | grep "wbflush" :-)
8  *
9  * This file is subject to the terms and conditions of the GNU General Public
10  * License.  See the file "COPYING" in the main directory of this archive
11  * for more details.
12  *
13  * Copyright (C) 1998 Harald Koerfgen
14  * Copyright (C) 2002 Maciej W. Rozycki
15  */
16 
17 #include <linux/export.h>
18 #include <linux/init.h>
19 
20 #include <asm/bootinfo.h>
21 #include <asm/wbflush.h>
22 #include <asm/barrier.h>
23 
24 static void wbflush_kn01(void);
25 static void wbflush_kn210(void);
26 static void wbflush_mips(void);
27 
28 void (*__wbflush) (void);
29 
wbflush_setup(void)30 void __init wbflush_setup(void)
31 {
32 	switch (mips_machtype) {
33 	case MACH_DS23100:
34 	case MACH_DS5000_200:	/* DS5000 3max */
35 		__wbflush = wbflush_kn01;
36 		break;
37 	case MACH_DS5100:	/* DS5100 MIPSMATE */
38 		__wbflush = wbflush_kn210;
39 		break;
40 	case MACH_DS5000_1XX:	/* DS5000/100 3min */
41 	case MACH_DS5000_XX:	/* Personal DS5000/2x */
42 	case MACH_DS5000_2X0:	/* DS5000/240 3max+ */
43 	case MACH_DS5900:	/* DS5900 bigmax */
44 	default:
45 		__wbflush = wbflush_mips;
46 		break;
47 	}
48 }
49 
50 /*
51  * For the DS3100 and DS5000/200 the R2020/R3220 writeback buffer functions
52  * as part of Coprocessor 0.
53  */
wbflush_kn01(void)54 static void wbflush_kn01(void)
55 {
56     asm(".set\tpush\n\t"
57 	".set\tnoreorder\n\t"
58 	"1:\tbc0f\t1b\n\t"
59 	"nop\n\t"
60 	".set\tpop");
61 }
62 
63 /*
64  * For the DS5100 the writeback buffer seems to be a part of Coprocessor 3.
65  * But CP3 has to enabled first.
66  */
wbflush_kn210(void)67 static void wbflush_kn210(void)
68 {
69     asm(".set\tpush\n\t"
70 	".set\tnoreorder\n\t"
71 	"mfc0\t$2,$12\n\t"
72 	"lui\t$3,0x8000\n\t"
73 	"or\t$3,$2,$3\n\t"
74 	"mtc0\t$3,$12\n\t"
75 	"nop\n"
76 	"1:\tbc3f\t1b\n\t"
77 	"nop\n\t"
78 	"mtc0\t$2,$12\n\t"
79 	"nop\n\t"
80 	".set\tpop"
81 	: : : "$2", "$3");
82 }
83 
84 /*
85  * I/O ASIC systems use a standard writeback buffer that gets flushed
86  * upon an uncached read.
87  */
wbflush_mips(void)88 static void wbflush_mips(void)
89 {
90 	__fast_iob();
91 }
92 EXPORT_SYMBOL(__wbflush);
93