1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2016 Imagination Technologies
4 * Author: Paul Burton <paul.burton@mips.com>
5 */
6
7 #define pr_fmt(fmt) "yamon-dt: " fmt
8
9 #include <linux/bug.h>
10 #include <linux/errno.h>
11 #include <linux/kernel.h>
12 #include <linux/libfdt.h>
13 #include <linux/printk.h>
14
15 #include <asm/fw/fw.h>
16 #include <asm/yamon-dt.h>
17
18 #define MAX_MEM_ARRAY_ENTRIES 2
19
yamon_dt_append_cmdline(void * fdt)20 __init int yamon_dt_append_cmdline(void *fdt)
21 {
22 int err, chosen_off;
23
24 /* find or add chosen node */
25 chosen_off = fdt_path_offset(fdt, "/chosen");
26 if (chosen_off == -FDT_ERR_NOTFOUND)
27 chosen_off = fdt_add_subnode(fdt, 0, "chosen");
28 if (chosen_off < 0) {
29 pr_err("Unable to find or add DT chosen node: %d\n",
30 chosen_off);
31 return chosen_off;
32 }
33
34 err = fdt_setprop_string(fdt, chosen_off, "bootargs", fw_getcmdline());
35 if (err) {
36 pr_err("Unable to set bootargs property: %d\n", err);
37 return err;
38 }
39
40 return 0;
41 }
42
gen_fdt_mem_array(const struct yamon_mem_region * regions,__be32 * mem_array,unsigned int max_entries,unsigned long memsize)43 static unsigned int __init gen_fdt_mem_array(
44 const struct yamon_mem_region *regions,
45 __be32 *mem_array,
46 unsigned int max_entries,
47 unsigned long memsize)
48 {
49 const struct yamon_mem_region *mr;
50 unsigned long size;
51 unsigned int entries = 0;
52
53 for (mr = regions; mr->size && memsize; ++mr) {
54 if (entries >= max_entries) {
55 pr_warn("Number of regions exceeds max %u\n",
56 max_entries);
57 break;
58 }
59
60 /* How much of the remaining RAM fits in the next region? */
61 size = min_t(unsigned long, memsize, mr->size);
62 memsize -= size;
63
64 /* Emit a memory region */
65 *(mem_array++) = cpu_to_be32(mr->start);
66 *(mem_array++) = cpu_to_be32(size);
67 ++entries;
68
69 /* Discard the next mr->discard bytes */
70 memsize -= min_t(unsigned long, memsize, mr->discard);
71 }
72 return entries;
73 }
74
yamon_dt_append_memory(void * fdt,const struct yamon_mem_region * regions)75 __init int yamon_dt_append_memory(void *fdt,
76 const struct yamon_mem_region *regions)
77 {
78 unsigned long phys_memsize = 0, memsize;
79 __be32 mem_array[2 * MAX_MEM_ARRAY_ENTRIES];
80 unsigned int mem_entries;
81 int i, err, mem_off;
82 char *var, param_name[10], *var_names[] = {
83 "ememsize", "memsize",
84 };
85
86 /* find memory size from the bootloader environment */
87 for (i = 0; i < ARRAY_SIZE(var_names); i++) {
88 var = fw_getenv(var_names[i]);
89 if (!var)
90 continue;
91
92 err = kstrtoul(var, 0, &phys_memsize);
93 if (!err)
94 break;
95
96 pr_warn("Failed to read the '%s' env variable '%s'\n",
97 var_names[i], var);
98 }
99
100 if (!phys_memsize) {
101 pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
102 phys_memsize = 32 << 20;
103 }
104
105 /* default to using all available RAM */
106 memsize = phys_memsize;
107
108 /* allow the user to override the usable memory */
109 for (i = 0; i < ARRAY_SIZE(var_names); i++) {
110 snprintf(param_name, sizeof(param_name), "%s=", var_names[i]);
111 var = strstr(arcs_cmdline, param_name);
112 if (!var)
113 continue;
114
115 memsize = memparse(var + strlen(param_name), NULL);
116 }
117
118 /* if the user says there's more RAM than we thought, believe them */
119 phys_memsize = max_t(unsigned long, phys_memsize, memsize);
120
121 /* find or add a memory node */
122 mem_off = fdt_path_offset(fdt, "/memory");
123 if (mem_off == -FDT_ERR_NOTFOUND)
124 mem_off = fdt_add_subnode(fdt, 0, "memory");
125 if (mem_off < 0) {
126 pr_err("Unable to find or add memory DT node: %d\n", mem_off);
127 return mem_off;
128 }
129
130 err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
131 if (err) {
132 pr_err("Unable to set memory node device_type: %d\n", err);
133 return err;
134 }
135
136 mem_entries = gen_fdt_mem_array(regions, mem_array,
137 MAX_MEM_ARRAY_ENTRIES, phys_memsize);
138 err = fdt_setprop(fdt, mem_off, "reg",
139 mem_array, mem_entries * 2 * sizeof(mem_array[0]));
140 if (err) {
141 pr_err("Unable to set memory regs property: %d\n", err);
142 return err;
143 }
144
145 mem_entries = gen_fdt_mem_array(regions, mem_array,
146 MAX_MEM_ARRAY_ENTRIES, memsize);
147 err = fdt_setprop(fdt, mem_off, "linux,usable-memory",
148 mem_array, mem_entries * 2 * sizeof(mem_array[0]));
149 if (err) {
150 pr_err("Unable to set linux,usable-memory property: %d\n", err);
151 return err;
152 }
153
154 return 0;
155 }
156
yamon_dt_serial_config(void * fdt)157 __init int yamon_dt_serial_config(void *fdt)
158 {
159 const char *yamontty, *mode_var;
160 char mode_var_name[9], path[20], parity;
161 unsigned int uart, baud, stop_bits;
162 bool hw_flow;
163 int chosen_off, err;
164
165 yamontty = fw_getenv("yamontty");
166 if (!yamontty || !strcmp(yamontty, "tty0")) {
167 uart = 0;
168 } else if (!strcmp(yamontty, "tty1")) {
169 uart = 1;
170 } else {
171 pr_warn("yamontty environment variable '%s' invalid\n",
172 yamontty);
173 uart = 0;
174 }
175
176 baud = stop_bits = 0;
177 parity = 0;
178 hw_flow = false;
179
180 snprintf(mode_var_name, sizeof(mode_var_name), "modetty%u", uart);
181 mode_var = fw_getenv(mode_var_name);
182 if (mode_var) {
183 while (mode_var[0] >= '0' && mode_var[0] <= '9') {
184 baud *= 10;
185 baud += mode_var[0] - '0';
186 mode_var++;
187 }
188 if (mode_var[0] == ',')
189 mode_var++;
190 if (mode_var[0])
191 parity = mode_var[0];
192 if (mode_var[0] == ',')
193 mode_var++;
194 if (mode_var[0])
195 stop_bits = mode_var[0] - '0';
196 if (mode_var[0] == ',')
197 mode_var++;
198 if (!strcmp(mode_var, "hw"))
199 hw_flow = true;
200 }
201
202 if (!baud)
203 baud = 38400;
204
205 if (parity != 'e' && parity != 'n' && parity != 'o')
206 parity = 'n';
207
208 if (stop_bits != 7 && stop_bits != 8)
209 stop_bits = 8;
210
211 WARN_ON(snprintf(path, sizeof(path), "serial%u:%u%c%u%s",
212 uart, baud, parity, stop_bits,
213 hw_flow ? "r" : "") >= sizeof(path));
214
215 /* find or add chosen node */
216 chosen_off = fdt_path_offset(fdt, "/chosen");
217 if (chosen_off == -FDT_ERR_NOTFOUND)
218 chosen_off = fdt_add_subnode(fdt, 0, "chosen");
219 if (chosen_off < 0) {
220 pr_err("Unable to find or add DT chosen node: %d\n",
221 chosen_off);
222 return chosen_off;
223 }
224
225 err = fdt_setprop_string(fdt, chosen_off, "stdout-path", path);
226 if (err) {
227 pr_err("Unable to set stdout-path property: %d\n", err);
228 return err;
229 }
230
231 return 0;
232 }
233