1 // SPDX-License-Identifier: GPL-2.0+
2 /*
3  * Copyright (C) 2023 Loongson Technology Corporation Limited
4  */
5 
6 #include "lsdc_drv.h"
7 #include "lsdc_probe.h"
8 
9 /*
10  * Processor ID (implementation) values for bits 15:8 of the PRID register.
11  */
12 #define LOONGSON_CPU_IMP_MASK           0xff00
13 #define LOONGSON_CPU_IMP_SHIFT          8
14 
15 #define LOONGARCH_CPU_IMP_LS2K1000      0xa0
16 #define LOONGARCH_CPU_IMP_LS2K2000      0xb0
17 #define LOONGARCH_CPU_IMP_LS3A5000      0xc0
18 
19 #define LOONGSON_CPU_MIPS_IMP_LS2K      0x61 /* Loongson 2K Mips series SoC */
20 
21 /*
22  * Particular Revision values for bits 7:0 of the PRID register.
23  */
24 #define LOONGSON_CPU_REV_MASK           0x00ff
25 
26 #define LOONGARCH_CPUCFG_PRID_REG       0x0
27 
28 /*
29  * We can achieve fine-grained control with the information about the host.
30  */
31 
32 unsigned int loongson_cpu_get_prid(u8 *imp, u8 *rev)
33 {
34 	unsigned int prid = 0;
35 
36 #if defined(__loongarch__)
37 	__asm__ volatile("cpucfg %0, %1\n\t"
38 			: "=&r"(prid)
39 			: "r"(LOONGARCH_CPUCFG_PRID_REG)
40 			);
41 #endif
42 
43 #if defined(__mips__)
44 	__asm__ volatile("mfc0\t%0, $15\n\t"
45 			: "=r" (prid)
46 			);
47 #endif
48 
49 	if (imp)
50 		*imp = (prid & LOONGSON_CPU_IMP_MASK) >> LOONGSON_CPU_IMP_SHIFT;
51 
52 	if (rev)
53 		*rev = prid & LOONGSON_CPU_REV_MASK;
54 
55 	return prid;
56 }
57