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
ocelot_detect(void)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
ocelot_earlyprintk_init(void)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
ocelot_late_init(void)59 static void __init ocelot_late_init(void)
60 {
61 ocelot_earlyprintk_init();
62 }
63
ocelot_fixup_fdt(const void * fdt,const void * match_data)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