926a02b17b31f36df84655176aa5757f3b13a4a9
[muen/linux.git] / arch / nios2 / kernel / setup.c
1 /*
2  * Nios2-specific parts of system setup
3  *
4  * Copyright (C) 2010 Tobias Klauser <tklauser@distanz.ch>
5  * Copyright (C) 2004 Microtronix Datacom Ltd.
6  * Copyright (C) 2001 Vic Phillips <vic@microtronix.com>
7  *
8  * This file is subject to the terms and conditions of the GNU General Public
9  * License. See the file "COPYING" in the main directory of this archive
10  * for more details.
11  */
12
13 #include <linux/export.h>
14 #include <linux/kernel.h>
15 #include <linux/mm.h>
16 #include <linux/sched.h>
17 #include <linux/sched/task.h>
18 #include <linux/console.h>
19 #include <linux/bootmem.h>
20 #include <linux/initrd.h>
21 #include <linux/of_fdt.h>
22 #include <linux/screen_info.h>
23
24 #include <asm/mmu_context.h>
25 #include <asm/sections.h>
26 #include <asm/setup.h>
27 #include <asm/cpuinfo.h>
28
29 unsigned long memory_start;
30 EXPORT_SYMBOL(memory_start);
31
32 unsigned long memory_end;
33 EXPORT_SYMBOL(memory_end);
34
35 unsigned long memory_size;
36
37 static struct pt_regs fake_regs = { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
38                                         0, 0, 0, 0, 0, 0,
39                                         0};
40
41 #ifdef CONFIG_VT
42 struct screen_info screen_info;
43 #endif
44
45 /* Copy a short hook instruction sequence to the exception address */
46 static inline void copy_exception_handler(unsigned int addr)
47 {
48         unsigned int start = (unsigned int) exception_handler_hook;
49         volatile unsigned int tmp = 0;
50
51         if (start == addr) {
52                 /* The CPU exception address already points to the handler. */
53                 return;
54         }
55
56         __asm__ __volatile__ (
57                 "ldw    %2,0(%0)\n"
58                 "stw    %2,0(%1)\n"
59                 "ldw    %2,4(%0)\n"
60                 "stw    %2,4(%1)\n"
61                 "ldw    %2,8(%0)\n"
62                 "stw    %2,8(%1)\n"
63                 "flushd 0(%1)\n"
64                 "flushd 4(%1)\n"
65                 "flushd 8(%1)\n"
66                 "flushi %1\n"
67                 "addi   %1,%1,4\n"
68                 "flushi %1\n"
69                 "addi   %1,%1,4\n"
70                 "flushi %1\n"
71                 "flushp\n"
72                 : /* no output registers */
73                 : "r" (start), "r" (addr), "r" (tmp)
74                 : "memory"
75         );
76 }
77
78 /* Copy the fast TLB miss handler */
79 static inline void copy_fast_tlb_miss_handler(unsigned int addr)
80 {
81         unsigned int start = (unsigned int) fast_handler;
82         unsigned int end = (unsigned int) fast_handler_end;
83         volatile unsigned int tmp = 0;
84
85         __asm__ __volatile__ (
86                 "1:\n"
87                 "       ldw     %3,0(%0)\n"
88                 "       stw     %3,0(%1)\n"
89                 "       flushd  0(%1)\n"
90                 "       flushi  %1\n"
91                 "       flushp\n"
92                 "       addi    %0,%0,4\n"
93                 "       addi    %1,%1,4\n"
94                 "       bne     %0,%2,1b\n"
95                 : /* no output registers */
96                 : "r" (start), "r" (addr), "r" (end), "r" (tmp)
97                 : "memory"
98         );
99 }
100
101 /*
102  * save args passed from u-boot, called from head.S
103  *
104  * @r4: NIOS magic
105  * @r5: initrd start
106  * @r6: initrd end or fdt
107  * @r7: kernel command line
108  */
109 asmlinkage void __init nios2_boot_init(unsigned r4, unsigned r5, unsigned r6,
110                                        unsigned r7)
111 {
112         unsigned dtb_passed = 0;
113         char cmdline_passed[COMMAND_LINE_SIZE] __maybe_unused = { 0, };
114
115 #if defined(CONFIG_NIOS2_PASS_CMDLINE)
116         if (r4 == 0x534f494e) { /* r4 is magic NIOS */
117 #if defined(CONFIG_BLK_DEV_INITRD)
118                 if (r5) { /* initramfs */
119                         initrd_start = r5;
120                         initrd_end = r6;
121                 }
122 #endif /* CONFIG_BLK_DEV_INITRD */
123                 dtb_passed = r6;
124
125                 if (r7)
126                         strncpy(cmdline_passed, (char *)r7, COMMAND_LINE_SIZE);
127         }
128 #endif
129
130         early_init_devtree((void *)dtb_passed);
131
132 #ifndef CONFIG_CMDLINE_FORCE
133         if (cmdline_passed[0])
134                 strncpy(boot_command_line, cmdline_passed, COMMAND_LINE_SIZE);
135 #ifdef CONFIG_NIOS2_CMDLINE_IGNORE_DTB
136         else
137                 strncpy(boot_command_line, CONFIG_CMDLINE, COMMAND_LINE_SIZE);
138 #endif
139 #endif
140
141         parse_early_param();
142 }
143
144 void __init setup_arch(char **cmdline_p)
145 {
146         int bootmap_size;
147
148         console_verbose();
149
150         memory_start = PAGE_ALIGN((unsigned long)__pa(_end));
151         memory_end = (unsigned long) CONFIG_NIOS2_MEM_BASE + memory_size;
152
153         init_mm.start_code = (unsigned long) _stext;
154         init_mm.end_code = (unsigned long) _etext;
155         init_mm.end_data = (unsigned long) _edata;
156         init_mm.brk = (unsigned long) _end;
157         init_task.thread.kregs = &fake_regs;
158
159         /* Keep a copy of command line */
160         *cmdline_p = boot_command_line;
161
162         min_low_pfn = PFN_UP(memory_start);
163         max_low_pfn = PFN_DOWN(memory_end);
164         max_mapnr = max_low_pfn;
165
166         /*
167          * give all the memory to the bootmap allocator,  tell it to put the
168          * boot mem_map at the start of memory
169          */
170         pr_debug("init_bootmem_node(?,%#lx, %#x, %#lx)\n",
171                 min_low_pfn, PFN_DOWN(PHYS_OFFSET), max_low_pfn);
172         bootmap_size = init_bootmem_node(NODE_DATA(0),
173                                         min_low_pfn, PFN_DOWN(PHYS_OFFSET),
174                                         max_low_pfn);
175
176         /*
177          * free the usable memory,  we have to make sure we do not free
178          * the bootmem bitmap so we then reserve it after freeing it :-)
179          */
180         pr_debug("free_bootmem(%#lx, %#lx)\n",
181                 memory_start, memory_end - memory_start);
182         free_bootmem(memory_start, memory_end - memory_start);
183
184         /*
185          * Reserve the bootmem bitmap itself as well. We do this in two
186          * steps (first step was init_bootmem()) because this catches
187          * the (very unlikely) case of us accidentally initializing the
188          * bootmem allocator with an invalid RAM area.
189          *
190          * Arguments are start, size
191          */
192         pr_debug("reserve_bootmem(%#lx, %#x)\n", memory_start, bootmap_size);
193         reserve_bootmem(memory_start, bootmap_size, BOOTMEM_DEFAULT);
194
195 #ifdef CONFIG_BLK_DEV_INITRD
196         if (initrd_start) {
197                 reserve_bootmem(virt_to_phys((void *)initrd_start),
198                                 initrd_end - initrd_start, BOOTMEM_DEFAULT);
199         }
200 #endif /* CONFIG_BLK_DEV_INITRD */
201
202         early_init_fdt_reserve_self();
203         early_init_fdt_scan_reserved_mem();
204
205         unflatten_and_copy_device_tree();
206
207         setup_cpuinfo();
208
209         copy_exception_handler(cpuinfo.exception_addr);
210
211         mmu_init();
212
213         copy_fast_tlb_miss_handler(cpuinfo.fast_tlb_miss_exc_addr);
214
215         /*
216          * Initialize MMU context handling here because data from cpuinfo is
217          * needed for this.
218          */
219         mmu_context_init();
220
221         /*
222          * get kmalloc into gear
223          */
224         paging_init();
225
226 #if defined(CONFIG_VT) && defined(CONFIG_DUMMY_CONSOLE)
227         conswitchp = &dummy_con;
228 #endif
229 }