drivers/gpu/drm/loongson/lsdc_probe.c

   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 }