xref: /linux/arch/microblaze/kernel/cpu/pvr.c (revision c0c914eca7f251c70facc37dfebeaf176601918d)
1 /*
2  * Support for MicroBlaze PVR (processor version register)
3  *
4  * Copyright (C) 2007-2009 Michal Simek <monstr@monstr.eu>
5  * Copyright (C) 2007-2009 PetaLogix
6  * Copyright (C) 2007 John Williams <john.williams@petalogix.com>
7  *
8  * This file is subject to the terms and conditions of the GNU General Public
9  * License. See the file "COPYING" in the main directory of this archive
10  * for more details.
11  */
12 
13 #include <linux/kernel.h>
14 #include <linux/compiler.h>
15 #include <asm/exceptions.h>
16 #include <asm/pvr.h>
17 
18 /*
19  * Until we get an assembler that knows about the pvr registers,
20  * this horrible cruft will have to do.
21  * That hardcoded opcode is mfs r3, rpvrNN
22  */
23 
24 #define get_single_pvr(pvrid, val)				\
25 {								\
26 	register unsigned tmp __asm__("r3");			\
27 	tmp = 0x0;	/* Prevent warning about unused */	\
28 	__asm__ __volatile__ (					\
29 			"mfs	%0, rpvr" #pvrid ";"		\
30 			: "=r" (tmp) : : "memory");		\
31 	val = tmp;						\
32 }
33 
34 /*
35  * Does the CPU support the PVR register?
36  * return value:
37  * 0: no PVR
38  * 1: simple PVR
39  * 2: full PVR
40  *
41  * This must work on all CPU versions, including those before the
42  * PVR was even an option.
43  */
44 
45 int cpu_has_pvr(void)
46 {
47 	unsigned long flags;
48 	unsigned pvr0;
49 
50 	local_save_flags(flags);
51 
52 	/* PVR bit in MSR tells us if there is any support */
53 	if (!(flags & PVR_MSR_BIT))
54 		return 0;
55 
56 	get_single_pvr(0, pvr0);
57 	pr_debug("%s: pvr0 is 0x%08x\n", __func__, pvr0);
58 
59 	if (pvr0 & PVR0_PVR_FULL_MASK)
60 		return 1;
61 
62 	/* for partial PVR use static cpuinfo */
63 	return 2;
64 }
65 
66 void get_pvr(struct pvr_s *p)
67 {
68 	get_single_pvr(0, p->pvr[0]);
69 	get_single_pvr(1, p->pvr[1]);
70 	get_single_pvr(2, p->pvr[2]);
71 	get_single_pvr(3, p->pvr[3]);
72 	get_single_pvr(4, p->pvr[4]);
73 	get_single_pvr(5, p->pvr[5]);
74 	get_single_pvr(6, p->pvr[6]);
75 	get_single_pvr(7, p->pvr[7]);
76 	get_single_pvr(8, p->pvr[8]);
77 	get_single_pvr(9, p->pvr[9]);
78 	get_single_pvr(10, p->pvr[10]);
79 	get_single_pvr(11, p->pvr[11]);
80 }
81