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 <linux/string.h> 8 #include <asm/machine.h> 9 #include <asm/prom.h> 10 11 #define DEVCPU_GCB_CHIP_REGS_CHIP_ID 0x71070000 12 #define CHIP_ID_PART_ID GENMASK(27, 12) 13 14 #define OCELOT_PART_ID (0x7514 << 12) 15 16 #define UART_UART 0x70100000 17 18 static __init bool ocelot_detect(void) 19 { 20 u32 rev; 21 int idx; 22 23 /* Look for the TLB entry set up by redboot before trying to use it */ 24 write_c0_entryhi(DEVCPU_GCB_CHIP_REGS_CHIP_ID); 25 mtc0_tlbw_hazard(); 26 tlb_probe(); 27 tlb_probe_hazard(); 28 idx = read_c0_index(); 29 if (idx < 0) 30 return false; 31 32 /* A TLB entry exists, lets assume its usable and check the CHIP ID */ 33 rev = __raw_readl((void __iomem *)DEVCPU_GCB_CHIP_REGS_CHIP_ID); 34 35 if ((rev & CHIP_ID_PART_ID) != OCELOT_PART_ID) 36 return false; 37 38 /* Copy command line from bootloader early for Initrd detection */ 39 if (fw_arg0 < 10 && (fw_arg1 & 0xFFF00000) == 0x80000000) { 40 unsigned int prom_argc = fw_arg0; 41 const char **prom_argv = (const char **)fw_arg1; 42 43 if (prom_argc > 1 && strlen(prom_argv[1]) > 0) 44 /* ignore all built-in args if any f/w args given */ 45 strscpy(arcs_cmdline, prom_argv[1]); 46 } 47 48 return true; 49 } 50 51 static void __init ocelot_earlyprintk_init(void) 52 { 53 void __iomem *uart_base; 54 55 uart_base = ioremap(UART_UART, 0x20); 56 setup_8250_early_printk_port((unsigned long)uart_base, 2, 50000); 57 } 58 59 static void __init ocelot_late_init(void) 60 { 61 ocelot_earlyprintk_init(); 62 } 63 64 static __init const void *ocelot_fixup_fdt(const void *fdt, 65 const void *match_data) 66 { 67 /* This has to be done so late because ioremap needs to work */ 68 late_time_init = ocelot_late_init; 69 70 return fdt; 71 } 72 73 extern char __dtb_ocelot_pcb123_begin[]; 74 75 MIPS_MACHINE(ocelot) = { 76 .fdt = __dtb_ocelot_pcb123_begin, 77 .fixup_fdt = ocelot_fixup_fdt, 78 .detect = ocelot_detect, 79 }; 80