xref: /openbmc/linux/arch/microblaze/kernel/cpu/pvr.c (revision 2cf1c348)
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 #include <linux/irqflags.h>
18 
19 /*
20  * Until we get an assembler that knows about the pvr registers,
21  * this horrible cruft will have to do.
22  * That hardcoded opcode is mfs r3, rpvrNN
23  */
24 
25 #define get_single_pvr(pvrid, val)				\
26 {								\
27 	register unsigned tmp __asm__("r3");			\
28 	tmp = 0x0;	/* Prevent warning about unused */	\
29 	__asm__ __volatile__ (					\
30 			"mfs	%0, rpvr" #pvrid ";"		\
31 			: "=r" (tmp) : : "memory");		\
32 	val = tmp;						\
33 }
34 
35 /*
36  * Does the CPU support the PVR register?
37  * return value:
38  * 0: no PVR
39  * 1: simple PVR
40  * 2: full PVR
41  *
42  * This must work on all CPU versions, including those before the
43  * PVR was even an option.
44  */
45 
46 int cpu_has_pvr(void)
47 {
48 	unsigned long flags;
49 	unsigned pvr0;
50 
51 	local_save_flags(flags);
52 
53 	/* PVR bit in MSR tells us if there is any support */
54 	if (!(flags & PVR_MSR_BIT))
55 		return 0;
56 
57 	get_single_pvr(0, pvr0);
58 	pr_debug("%s: pvr0 is 0x%08x\n", __func__, pvr0);
59 
60 	if (pvr0 & PVR0_PVR_FULL_MASK)
61 		return 1;
62 
63 	/* for partial PVR use static cpuinfo */
64 	return 2;
65 }
66 
67 void get_pvr(struct pvr_s *p)
68 {
69 	get_single_pvr(0, p->pvr[0]);
70 	get_single_pvr(1, p->pvr[1]);
71 	get_single_pvr(2, p->pvr[2]);
72 	get_single_pvr(3, p->pvr[3]);
73 	get_single_pvr(4, p->pvr[4]);
74 	get_single_pvr(5, p->pvr[5]);
75 	get_single_pvr(6, p->pvr[6]);
76 	get_single_pvr(7, p->pvr[7]);
77 	get_single_pvr(8, p->pvr[8]);
78 	get_single_pvr(9, p->pvr[9]);
79 	get_single_pvr(10, p->pvr[10]);
80 	get_single_pvr(11, p->pvr[11]);
81 }
82