1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2015 Imagination Technologies
4  * Author: Paul Burton <paul.burton@mips.com>
5  */
6 
7 #include <linux/bug.h>
8 #include <linux/kernel.h>
9 #include <linux/libfdt.h>
10 #include <linux/of_fdt.h>
11 #include <linux/sizes.h>
12 #include <asm/addrspace.h>
13 #include <asm/bootinfo.h>
14 #include <asm/fw/fw.h>
15 #include <asm/mips-boards/generic.h>
16 #include <asm/mips-boards/malta.h>
17 #include <asm/mips-cps.h>
18 #include <asm/page.h>
19 
20 #define ROCIT_REG_BASE			0x1f403000
21 #define ROCIT_CONFIG_GEN1		(ROCIT_REG_BASE + 0x04)
22 #define  ROCIT_CONFIG_GEN1_MEMMAP_SHIFT	8
23 #define  ROCIT_CONFIG_GEN1_MEMMAP_MASK	(0xf << 8)
24 
25 static unsigned char fdt_buf[16 << 10] __initdata __aligned(8);
26 
27 /* determined physical memory size, not overridden by command line args	 */
28 extern unsigned long physical_memsize;
29 
30 enum mem_map {
31 	MEM_MAP_V1 = 0,
32 	MEM_MAP_V2,
33 };
34 
35 #define MAX_MEM_ARRAY_ENTRIES 2
36 
malta_scon(void)37 static __init int malta_scon(void)
38 {
39 	int scon = MIPS_REVISION_SCONID;
40 
41 	if (scon != MIPS_REVISION_SCON_OTHER)
42 		return scon;
43 
44 	switch (MIPS_REVISION_CORID) {
45 	case MIPS_REVISION_CORID_QED_RM5261:
46 	case MIPS_REVISION_CORID_CORE_LV:
47 	case MIPS_REVISION_CORID_CORE_FPGA:
48 	case MIPS_REVISION_CORID_CORE_FPGAR2:
49 		return MIPS_REVISION_SCON_GT64120;
50 
51 	case MIPS_REVISION_CORID_CORE_EMUL_BON:
52 	case MIPS_REVISION_CORID_BONITO64:
53 	case MIPS_REVISION_CORID_CORE_20K:
54 		return MIPS_REVISION_SCON_BONITO;
55 
56 	case MIPS_REVISION_CORID_CORE_MSC:
57 	case MIPS_REVISION_CORID_CORE_FPGA2:
58 	case MIPS_REVISION_CORID_CORE_24K:
59 		return MIPS_REVISION_SCON_SOCIT;
60 
61 	case MIPS_REVISION_CORID_CORE_FPGA3:
62 	case MIPS_REVISION_CORID_CORE_FPGA4:
63 	case MIPS_REVISION_CORID_CORE_FPGA5:
64 	case MIPS_REVISION_CORID_CORE_EMUL_MSC:
65 	default:
66 		return MIPS_REVISION_SCON_ROCIT;
67 	}
68 }
69 
gen_fdt_mem_array(__be32 * mem_array,unsigned long size,enum mem_map map)70 static unsigned __init gen_fdt_mem_array(__be32 *mem_array, unsigned long size,
71 					 enum mem_map map)
72 {
73 	unsigned long size_preio;
74 	unsigned entries;
75 
76 	entries = 1;
77 	mem_array[0] = cpu_to_be32(PHYS_OFFSET);
78 	if (IS_ENABLED(CONFIG_EVA)) {
79 		/*
80 		 * The current Malta EVA configuration is "special" in that it
81 		 * always makes use of addresses in the upper half of the 32 bit
82 		 * physical address map, which gives it a contiguous region of
83 		 * DDR but limits it to 2GB.
84 		 */
85 		mem_array[1] = cpu_to_be32(size);
86 		goto done;
87 	}
88 
89 	size_preio = min_t(unsigned long, size, SZ_256M);
90 	mem_array[1] = cpu_to_be32(size_preio);
91 	size -= size_preio;
92 	if (!size)
93 		goto done;
94 
95 	if (map == MEM_MAP_V2) {
96 		/*
97 		 * We have a flat 32 bit physical memory map with DDR filling
98 		 * all 4GB of the memory map, apart from the I/O region which
99 		 * obscures 256MB from 0x10000000-0x1fffffff.
100 		 *
101 		 * Therefore we discard the 256MB behind the I/O region.
102 		 */
103 		if (size <= SZ_256M)
104 			goto done;
105 		size -= SZ_256M;
106 
107 		/* Make use of the memory following the I/O region */
108 		entries++;
109 		mem_array[2] = cpu_to_be32(PHYS_OFFSET + SZ_512M);
110 		mem_array[3] = cpu_to_be32(size);
111 	} else {
112 		/*
113 		 * We have a 32 bit physical memory map with a 2GB DDR region
114 		 * aliased in the upper & lower halves of it. The I/O region
115 		 * obscures 256MB from 0x10000000-0x1fffffff in the low alias
116 		 * but the DDR it obscures is accessible via the high alias.
117 		 *
118 		 * Simply access everything beyond the lowest 256MB of DDR using
119 		 * the high alias.
120 		 */
121 		entries++;
122 		mem_array[2] = cpu_to_be32(PHYS_OFFSET + SZ_2G + SZ_256M);
123 		mem_array[3] = cpu_to_be32(size);
124 	}
125 
126 done:
127 	BUG_ON(entries > MAX_MEM_ARRAY_ENTRIES);
128 	return entries;
129 }
130 
append_memory(void * fdt,int root_off)131 static void __init append_memory(void *fdt, int root_off)
132 {
133 	__be32 mem_array[2 * MAX_MEM_ARRAY_ENTRIES];
134 	unsigned long memsize;
135 	unsigned mem_entries;
136 	int i, err, mem_off;
137 	enum mem_map mem_map;
138 	u32 config;
139 	char *var, param_name[10], *var_names[] = {
140 		"ememsize", "memsize",
141 	};
142 
143 	/* if a memory node already exists, leave it alone */
144 	mem_off = fdt_path_offset(fdt, "/memory");
145 	if (mem_off >= 0)
146 		return;
147 
148 	/* find memory size from the bootloader environment */
149 	for (i = 0; i < ARRAY_SIZE(var_names); i++) {
150 		var = fw_getenv(var_names[i]);
151 		if (!var)
152 			continue;
153 
154 		err = kstrtoul(var, 0, &physical_memsize);
155 		if (!err)
156 			break;
157 
158 		pr_warn("Failed to read the '%s' env variable '%s'\n",
159 			var_names[i], var);
160 	}
161 
162 	if (!physical_memsize) {
163 		pr_warn("The bootloader didn't provide memsize: defaulting to 32MB\n");
164 		physical_memsize = 32 << 20;
165 	}
166 
167 	if (IS_ENABLED(CONFIG_CPU_BIG_ENDIAN)) {
168 		/*
169 		 * SOC-it swaps, or perhaps doesn't swap, when DMA'ing
170 		 * the last word of physical memory.
171 		 */
172 		physical_memsize -= PAGE_SIZE;
173 	}
174 
175 	/* default to using all available RAM */
176 	memsize = physical_memsize;
177 
178 	/* allow the user to override the usable memory */
179 	for (i = 0; i < ARRAY_SIZE(var_names); i++) {
180 		snprintf(param_name, sizeof(param_name), "%s=", var_names[i]);
181 		var = strstr(arcs_cmdline, param_name);
182 		if (!var)
183 			continue;
184 
185 		memsize = memparse(var + strlen(param_name), NULL);
186 	}
187 
188 	/* if the user says there's more RAM than we thought, believe them */
189 	physical_memsize = max_t(unsigned long, physical_memsize, memsize);
190 
191 	/* detect the memory map in use */
192 	if (malta_scon() == MIPS_REVISION_SCON_ROCIT) {
193 		/* ROCit has a register indicating the memory map in use */
194 		config = readl((void __iomem *)CKSEG1ADDR(ROCIT_CONFIG_GEN1));
195 		mem_map = config & ROCIT_CONFIG_GEN1_MEMMAP_MASK;
196 		mem_map >>= ROCIT_CONFIG_GEN1_MEMMAP_SHIFT;
197 	} else {
198 		/* if not using ROCit, presume the v1 memory map */
199 		mem_map = MEM_MAP_V1;
200 	}
201 	if (mem_map > MEM_MAP_V2)
202 		panic("Unsupported physical memory map v%u detected",
203 		      (unsigned int)mem_map);
204 
205 	/* append memory to the DT */
206 	mem_off = fdt_add_subnode(fdt, root_off, "memory");
207 	if (mem_off < 0)
208 		panic("Unable to add memory node to DT: %d", mem_off);
209 
210 	err = fdt_setprop_string(fdt, mem_off, "device_type", "memory");
211 	if (err)
212 		panic("Unable to set memory node device_type: %d", err);
213 
214 	mem_entries = gen_fdt_mem_array(mem_array, physical_memsize, mem_map);
215 	err = fdt_setprop(fdt, mem_off, "reg", mem_array,
216 			  mem_entries * 2 * sizeof(mem_array[0]));
217 	if (err)
218 		panic("Unable to set memory regs property: %d", err);
219 
220 	mem_entries = gen_fdt_mem_array(mem_array, memsize, mem_map);
221 	err = fdt_setprop(fdt, mem_off, "linux,usable-memory", mem_array,
222 			  mem_entries * 2 * sizeof(mem_array[0]));
223 	if (err)
224 		panic("Unable to set linux,usable-memory property: %d", err);
225 }
226 
remove_gic(void * fdt)227 static void __init remove_gic(void *fdt)
228 {
229 	int err, gic_off, i8259_off, cpu_off;
230 	void __iomem *biu_base;
231 	uint32_t cpu_phandle, sc_cfg;
232 
233 	/* if we have a CM which reports a GIC is present, leave the DT alone */
234 	err = mips_cm_probe();
235 	if (!err && (read_gcr_gic_status() & CM_GCR_GIC_STATUS_EX))
236 		return;
237 
238 	if (malta_scon() == MIPS_REVISION_SCON_ROCIT) {
239 		/*
240 		 * On systems using the RocIT system controller a GIC may be
241 		 * present without a CM. Detect whether that is the case.
242 		 */
243 		biu_base = ioremap(MSC01_BIU_REG_BASE,
244 				MSC01_BIU_ADDRSPACE_SZ);
245 		sc_cfg = __raw_readl(biu_base + MSC01_SC_CFG_OFS);
246 		if (sc_cfg & MSC01_SC_CFG_GICPRES_MSK) {
247 			/* enable the GIC at the system controller level */
248 			sc_cfg |= BIT(MSC01_SC_CFG_GICENA_SHF);
249 			__raw_writel(sc_cfg, biu_base + MSC01_SC_CFG_OFS);
250 			return;
251 		}
252 	}
253 
254 	gic_off = fdt_node_offset_by_compatible(fdt, -1, "mti,gic");
255 	if (gic_off < 0) {
256 		pr_warn("malta-dtshim: unable to find DT GIC node: %d\n",
257 			gic_off);
258 		return;
259 	}
260 
261 	err = fdt_nop_node(fdt, gic_off);
262 	if (err)
263 		pr_warn("malta-dtshim: unable to nop GIC node\n");
264 
265 	i8259_off = fdt_node_offset_by_compatible(fdt, -1, "intel,i8259");
266 	if (i8259_off < 0) {
267 		pr_warn("malta-dtshim: unable to find DT i8259 node: %d\n",
268 			i8259_off);
269 		return;
270 	}
271 
272 	cpu_off = fdt_node_offset_by_compatible(fdt, -1,
273 			"mti,cpu-interrupt-controller");
274 	if (cpu_off < 0) {
275 		pr_warn("malta-dtshim: unable to find CPU intc node: %d\n",
276 			cpu_off);
277 		return;
278 	}
279 
280 	cpu_phandle = fdt_get_phandle(fdt, cpu_off);
281 	if (!cpu_phandle) {
282 		pr_warn("malta-dtshim: unable to get CPU intc phandle\n");
283 		return;
284 	}
285 
286 	err = fdt_setprop_u32(fdt, i8259_off, "interrupt-parent", cpu_phandle);
287 	if (err) {
288 		pr_warn("malta-dtshim: unable to set i8259 interrupt-parent: %d\n",
289 			err);
290 		return;
291 	}
292 
293 	err = fdt_setprop_u32(fdt, i8259_off, "interrupts", 2);
294 	if (err) {
295 		pr_warn("malta-dtshim: unable to set i8259 interrupts: %d\n",
296 			err);
297 		return;
298 	}
299 }
300 
malta_dt_shim(void * fdt)301 void __init *malta_dt_shim(void *fdt)
302 {
303 	int root_off, len, err;
304 	const char *compat;
305 
306 	if (fdt_check_header(fdt))
307 		panic("Corrupt DT");
308 
309 	err = fdt_open_into(fdt, fdt_buf, sizeof(fdt_buf));
310 	if (err)
311 		panic("Unable to open FDT: %d", err);
312 
313 	root_off = fdt_path_offset(fdt_buf, "/");
314 	if (root_off < 0)
315 		panic("No / node in DT");
316 
317 	compat = fdt_getprop(fdt_buf, root_off, "compatible", &len);
318 	if (!compat)
319 		panic("No root compatible property in DT: %d", len);
320 
321 	/* if this isn't Malta, leave the DT alone */
322 	if (strncmp(compat, "mti,malta", len))
323 		return fdt;
324 
325 	append_memory(fdt_buf, root_off);
326 	remove_gic(fdt_buf);
327 
328 	err = fdt_pack(fdt_buf);
329 	if (err)
330 		panic("Unable to pack FDT: %d\n", err);
331 
332 	return fdt_buf;
333 }
334