xref: /openbmc/linux/arch/sh/kernel/cpu/sh3/probe.c (revision ca55b2fe)
1 /*
2  * arch/sh/kernel/cpu/sh3/probe.c
3  *
4  * CPU Subtype Probing for SH-3.
5  *
6  * Copyright (C) 1999, 2000  Niibe Yutaka
7  * Copyright (C) 2002  Paul Mundt
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 
14 #include <linux/init.h>
15 #include <asm/processor.h>
16 #include <asm/cache.h>
17 #include <asm/io.h>
18 
19 void cpu_probe(void)
20 {
21 	unsigned long addr0, addr1, data0, data1, data2, data3;
22 
23 	jump_to_uncached();
24 	/*
25 	 * Check if the entry shadows or not.
26 	 * When shadowed, it's 128-entry system.
27 	 * Otherwise, it's 256-entry system.
28 	 */
29 	addr0 = CACHE_OC_ADDRESS_ARRAY + (3 << 12);
30 	addr1 = CACHE_OC_ADDRESS_ARRAY + (1 << 12);
31 
32 	/* First, write back & invalidate */
33 	data0  = __raw_readl(addr0);
34 	__raw_writel(data0&~(SH_CACHE_VALID|SH_CACHE_UPDATED), addr0);
35 	data1  = __raw_readl(addr1);
36 	__raw_writel(data1&~(SH_CACHE_VALID|SH_CACHE_UPDATED), addr1);
37 
38 	/* Next, check if there's shadow or not */
39 	data0 = __raw_readl(addr0);
40 	data0 ^= SH_CACHE_VALID;
41 	__raw_writel(data0, addr0);
42 	data1 = __raw_readl(addr1);
43 	data2 = data1 ^ SH_CACHE_VALID;
44 	__raw_writel(data2, addr1);
45 	data3 = __raw_readl(addr0);
46 
47 	/* Lastly, invaliate them. */
48 	__raw_writel(data0&~SH_CACHE_VALID, addr0);
49 	__raw_writel(data2&~SH_CACHE_VALID, addr1);
50 
51 	back_to_cached();
52 
53 	boot_cpu_data.dcache.ways		= 4;
54 	boot_cpu_data.dcache.entry_shift	= 4;
55 	boot_cpu_data.dcache.linesz		= L1_CACHE_BYTES;
56 	boot_cpu_data.dcache.flags		= 0;
57 
58 	/*
59 	 * 7709A/7729 has 16K cache (256-entry), while 7702 has only
60 	 * 2K(direct) 7702 is not supported (yet)
61 	 */
62 	if (data0 == data1 && data2 == data3) {	/* Shadow */
63 		boot_cpu_data.dcache.way_incr	= (1 << 11);
64 		boot_cpu_data.dcache.entry_mask	= 0x7f0;
65 		boot_cpu_data.dcache.sets	= 128;
66 		boot_cpu_data.type = CPU_SH7708;
67 
68 		boot_cpu_data.flags |= CPU_HAS_MMU_PAGE_ASSOC;
69 	} else {				/* 7709A or 7729  */
70 		boot_cpu_data.dcache.way_incr	= (1 << 12);
71 		boot_cpu_data.dcache.entry_mask	= 0xff0;
72 		boot_cpu_data.dcache.sets	= 256;
73 		boot_cpu_data.type = CPU_SH7729;
74 
75 #if defined(CONFIG_CPU_SUBTYPE_SH7706)
76 		boot_cpu_data.type = CPU_SH7706;
77 #endif
78 #if defined(CONFIG_CPU_SUBTYPE_SH7710)
79 		boot_cpu_data.type = CPU_SH7710;
80 #endif
81 #if defined(CONFIG_CPU_SUBTYPE_SH7712)
82 		boot_cpu_data.type = CPU_SH7712;
83 #endif
84 #if defined(CONFIG_CPU_SUBTYPE_SH7720)
85 		boot_cpu_data.type = CPU_SH7720;
86 #endif
87 #if defined(CONFIG_CPU_SUBTYPE_SH7721)
88 		boot_cpu_data.type = CPU_SH7721;
89 #endif
90 #if defined(CONFIG_CPU_SUBTYPE_SH7705)
91 		boot_cpu_data.type = CPU_SH7705;
92 
93 #if defined(CONFIG_SH7705_CACHE_32KB)
94 		boot_cpu_data.dcache.way_incr	= (1 << 13);
95 		boot_cpu_data.dcache.entry_mask	= 0x1ff0;
96 		boot_cpu_data.dcache.sets	= 512;
97 		__raw_writel(CCR_CACHE_32KB, CCR3_REG);
98 #else
99 		__raw_writel(CCR_CACHE_16KB, CCR3_REG);
100 #endif
101 #endif
102 	}
103 
104 	/*
105 	 * SH-3 doesn't have separate caches
106 	 */
107 	boot_cpu_data.dcache.flags |= SH_CACHE_COMBINED;
108 	boot_cpu_data.icache = boot_cpu_data.dcache;
109 
110 	boot_cpu_data.family = CPU_FAMILY_SH3;
111 }
112