arch/mips/generic/board-ocelot.c

   1 // SPDX-License-Identifier: (GPL-2.0 OR MIT)
   2 /*
   3  * Microsemi MIPS SoC support
   4  *
   5  * Copyright (c) 2017 Microsemi Corporation
   6  */
   7 #include <asm/machine.h>
   8 #include <asm/prom.h>
   9
  10 #define DEVCPU_GCB_CHIP_REGS_CHIP_ID    0x71070000
  11 #define CHIP_ID_PART_ID                 GENMASK(27, 12)
  12
  13 #define OCELOT_PART_ID                  (0x7514 << 12)
  14
  15 #define UART_UART                       0x70100000
  16
  17 static __init bool ocelot_detect(void)
  18 {
  19         u32 rev;
  20         int idx;
  21
  22         /* Look for the TLB entry set up by redboot before trying to use it */
  23         write_c0_entryhi(DEVCPU_GCB_CHIP_REGS_CHIP_ID);
  24         mtc0_tlbw_hazard();
  25         tlb_probe();
  26         tlb_probe_hazard();
  27         idx = read_c0_index();
  28         if (idx < 0)
  29                 return 0;
  30
  31         /* A TLB entry exists, lets assume its usable and check the CHIP ID */
  32         rev = __raw_readl((void __iomem *)DEVCPU_GCB_CHIP_REGS_CHIP_ID);
  33
  34         if ((rev & CHIP_ID_PART_ID) != OCELOT_PART_ID)
  35                 return 0;
  36
  37         /* Copy command line from bootloader early for Initrd detection */
  38         if (fw_arg0 < 10 && (fw_arg1 & 0xFFF00000) == 0x80000000) {
  39                 unsigned int prom_argc = fw_arg0;
  40                 const char **prom_argv = (const char **)fw_arg1;
  41
  42                 if (prom_argc > 1 && strlen(prom_argv[1]) > 0)
  43                         /* ignore all built-in args if any f/w args given */
  44                         strcpy(arcs_cmdline, prom_argv[1]);
  45         }
  46
  47         return 1;
  48 }
  49
  50 static void __init ocelot_earlyprintk_init(void)
  51 {
  52         void __iomem *uart_base;
  53
  54         uart_base = ioremap(UART_UART, 0x20);
  55         setup_8250_early_printk_port((unsigned long)uart_base, 2, 50000);
  56 }
  57
  58 static void __init ocelot_late_init(void)
  59 {
  60         ocelot_earlyprintk_init();
  61 }
  62
  63 static __init const void *ocelot_fixup_fdt(const void *fdt,
  64                                            const void *match_data)
  65 {
  66         /* This has to be done so late because ioremap needs to work */
  67         late_time_init = ocelot_late_init;
  68
  69         return fdt;
  70 }
  71
  72 extern char __dtb_ocelot_pcb123_begin[];
  73
  74 MIPS_MACHINE(ocelot) = {
  75         .fdt = __dtb_ocelot_pcb123_begin,
  76         .fixup_fdt = ocelot_fixup_fdt,
  77         .detect = ocelot_detect,
  78 };