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1 /*
2  * Copyright (C) 2008-2009 ST-Ericsson AB
3  * License terms: GNU General Public License (GPL) version 2
4  * TCM memory handling for ARM systems
5  *
6  * Author: Linus Walleij <linus.walleij@stericsson.com>
7  * Author: Rickard Andersson <rickard.andersson@stericsson.com>
8  */
9 #include <linux/init.h>
10 #include <linux/kernel.h>
11 #include <linux/module.h>
12 #include <linux/stddef.h>
13 #include <linux/ioport.h>
14 #include <linux/genalloc.h>
15 #include <linux/string.h> /* memcpy */
16 #include <asm/cputype.h>
17 #include <asm/mach/map.h>
18 #include <asm/memory.h>
19 #include <asm/system_info.h>
20 #include "tcm.h"
21 
22 static struct gen_pool *tcm_pool;
23 static bool dtcm_present;
24 static bool itcm_present;
25 
26 /* TCM section definitions from the linker */
27 extern char __itcm_start, __sitcm_text, __eitcm_text;
28 extern char __dtcm_start, __sdtcm_data, __edtcm_data;
29 
30 /* These will be increased as we run */
31 u32 dtcm_end = DTCM_OFFSET;
32 u32 itcm_end = ITCM_OFFSET;
33 
34 /*
35  * TCM memory resources
36  */
37 static struct resource dtcm_res = {
38 	.name = "DTCM RAM",
39 	.start = DTCM_OFFSET,
40 	.end = DTCM_OFFSET,
41 	.flags = IORESOURCE_MEM
42 };
43 
44 static struct resource itcm_res = {
45 	.name = "ITCM RAM",
46 	.start = ITCM_OFFSET,
47 	.end = ITCM_OFFSET,
48 	.flags = IORESOURCE_MEM
49 };
50 
51 static struct map_desc dtcm_iomap[] __initdata = {
52 	{
53 		.virtual	= DTCM_OFFSET,
54 		.pfn		= __phys_to_pfn(DTCM_OFFSET),
55 		.length		= 0,
56 		.type		= MT_MEMORY_DTCM
57 	}
58 };
59 
60 static struct map_desc itcm_iomap[] __initdata = {
61 	{
62 		.virtual	= ITCM_OFFSET,
63 		.pfn		= __phys_to_pfn(ITCM_OFFSET),
64 		.length		= 0,
65 		.type		= MT_MEMORY_ITCM
66 	}
67 };
68 
69 /*
70  * Allocate a chunk of TCM memory
71  */
tcm_alloc(size_t len)72 void *tcm_alloc(size_t len)
73 {
74 	unsigned long vaddr;
75 
76 	if (!tcm_pool)
77 		return NULL;
78 
79 	vaddr = gen_pool_alloc(tcm_pool, len);
80 	if (!vaddr)
81 		return NULL;
82 
83 	return (void *) vaddr;
84 }
85 EXPORT_SYMBOL(tcm_alloc);
86 
87 /*
88  * Free a chunk of TCM memory
89  */
tcm_free(void * addr,size_t len)90 void tcm_free(void *addr, size_t len)
91 {
92 	gen_pool_free(tcm_pool, (unsigned long) addr, len);
93 }
94 EXPORT_SYMBOL(tcm_free);
95 
tcm_dtcm_present(void)96 bool tcm_dtcm_present(void)
97 {
98 	return dtcm_present;
99 }
100 EXPORT_SYMBOL(tcm_dtcm_present);
101 
tcm_itcm_present(void)102 bool tcm_itcm_present(void)
103 {
104 	return itcm_present;
105 }
106 EXPORT_SYMBOL(tcm_itcm_present);
107 
setup_tcm_bank(u8 type,u8 bank,u8 banks,u32 * offset)108 static int __init setup_tcm_bank(u8 type, u8 bank, u8 banks,
109 				  u32 *offset)
110 {
111 	const int tcm_sizes[16] = { 0, -1, -1, 4, 8, 16, 32, 64, 128,
112 				    256, 512, 1024, -1, -1, -1, -1 };
113 	u32 tcm_region;
114 	int tcm_size;
115 
116 	/*
117 	 * If there are more than one TCM bank of this type,
118 	 * select the TCM bank to operate on in the TCM selection
119 	 * register.
120 	 */
121 	if (banks > 1)
122 		asm("mcr	p15, 0, %0, c9, c2, 0"
123 		    : /* No output operands */
124 		    : "r" (bank));
125 
126 	/* Read the special TCM region register c9, 0 */
127 	if (!type)
128 		asm("mrc	p15, 0, %0, c9, c1, 0"
129 		    : "=r" (tcm_region));
130 	else
131 		asm("mrc	p15, 0, %0, c9, c1, 1"
132 		    : "=r" (tcm_region));
133 
134 	tcm_size = tcm_sizes[(tcm_region >> 2) & 0x0f];
135 	if (tcm_size < 0) {
136 		pr_err("CPU: %sTCM%d of unknown size\n",
137 		       type ? "I" : "D", bank);
138 		return -EINVAL;
139 	} else if (tcm_size > 32) {
140 		pr_err("CPU: %sTCM%d larger than 32k found\n",
141 		       type ? "I" : "D", bank);
142 		return -EINVAL;
143 	} else {
144 		pr_info("CPU: found %sTCM%d %dk @ %08x, %senabled\n",
145 			type ? "I" : "D",
146 			bank,
147 			tcm_size,
148 			(tcm_region & 0xfffff000U),
149 			(tcm_region & 1) ? "" : "not ");
150 	}
151 
152 	/* Not much fun you can do with a size 0 bank */
153 	if (tcm_size == 0)
154 		return 0;
155 
156 	/* Force move the TCM bank to where we want it, enable */
157 	tcm_region = *offset | (tcm_region & 0x00000ffeU) | 1;
158 
159 	if (!type)
160 		asm("mcr	p15, 0, %0, c9, c1, 0"
161 		    : /* No output operands */
162 		    : "r" (tcm_region));
163 	else
164 		asm("mcr	p15, 0, %0, c9, c1, 1"
165 		    : /* No output operands */
166 		    : "r" (tcm_region));
167 
168 	/* Increase offset */
169 	*offset += (tcm_size << 10);
170 
171 	pr_info("CPU: moved %sTCM%d %dk to %08x, enabled\n",
172 		type ? "I" : "D",
173 		bank,
174 		tcm_size,
175 		(tcm_region & 0xfffff000U));
176 	return 0;
177 }
178 
179 /*
180  * This initializes the TCM memory
181  */
tcm_init(void)182 void __init tcm_init(void)
183 {
184 	u32 tcm_status;
185 	u8 dtcm_banks;
186 	u8 itcm_banks;
187 	size_t dtcm_code_sz = &__edtcm_data - &__sdtcm_data;
188 	size_t itcm_code_sz = &__eitcm_text - &__sitcm_text;
189 	char *start;
190 	char *end;
191 	char *ram;
192 	int ret;
193 	int i;
194 
195 	/*
196 	 * Prior to ARMv5 there is no TCM, and trying to read the status
197 	 * register will hang the processor.
198 	 */
199 	if (cpu_architecture() < CPU_ARCH_ARMv5) {
200 		if (dtcm_code_sz || itcm_code_sz)
201 			pr_info("CPU TCM: %u bytes of DTCM and %u bytes of "
202 				"ITCM code compiled in, but no TCM present "
203 				"in pre-v5 CPU\n", dtcm_code_sz, itcm_code_sz);
204 		return;
205 	}
206 
207 	tcm_status = read_cpuid_tcmstatus();
208 	dtcm_banks = (tcm_status >> 16) & 0x03;
209 	itcm_banks = (tcm_status & 0x03);
210 
211 	/* Values greater than 2 for D/ITCM banks are "reserved" */
212 	if (dtcm_banks > 2)
213 		dtcm_banks = 0;
214 	if (itcm_banks > 2)
215 		itcm_banks = 0;
216 
217 	/* Setup DTCM if present */
218 	if (dtcm_banks > 0) {
219 		for (i = 0; i < dtcm_banks; i++) {
220 			ret = setup_tcm_bank(0, i, dtcm_banks, &dtcm_end);
221 			if (ret)
222 				return;
223 		}
224 		/* This means you compiled more code than fits into DTCM */
225 		if (dtcm_code_sz > (dtcm_end - DTCM_OFFSET)) {
226 			pr_info("CPU DTCM: %u bytes of code compiled to "
227 				"DTCM but only %lu bytes of DTCM present\n",
228 				dtcm_code_sz, (dtcm_end - DTCM_OFFSET));
229 			goto no_dtcm;
230 		}
231 		dtcm_res.end = dtcm_end - 1;
232 		request_resource(&iomem_resource, &dtcm_res);
233 		dtcm_iomap[0].length = dtcm_end - DTCM_OFFSET;
234 		iotable_init(dtcm_iomap, 1);
235 		/* Copy data from RAM to DTCM */
236 		start = &__sdtcm_data;
237 		end   = &__edtcm_data;
238 		ram   = &__dtcm_start;
239 		memcpy(start, ram, dtcm_code_sz);
240 		pr_debug("CPU DTCM: copied data from %p - %p\n",
241 			 start, end);
242 		dtcm_present = true;
243 	} else if (dtcm_code_sz) {
244 		pr_info("CPU DTCM: %u bytes of code compiled to DTCM but no "
245 			"DTCM banks present in CPU\n", dtcm_code_sz);
246 	}
247 
248 no_dtcm:
249 	/* Setup ITCM if present */
250 	if (itcm_banks > 0) {
251 		for (i = 0; i < itcm_banks; i++) {
252 			ret = setup_tcm_bank(1, i, itcm_banks, &itcm_end);
253 			if (ret)
254 				return;
255 		}
256 		/* This means you compiled more code than fits into ITCM */
257 		if (itcm_code_sz > (itcm_end - ITCM_OFFSET)) {
258 			pr_info("CPU ITCM: %u bytes of code compiled to "
259 				"ITCM but only %lu bytes of ITCM present\n",
260 				itcm_code_sz, (itcm_end - ITCM_OFFSET));
261 			return;
262 		}
263 		itcm_res.end = itcm_end - 1;
264 		request_resource(&iomem_resource, &itcm_res);
265 		itcm_iomap[0].length = itcm_end - ITCM_OFFSET;
266 		iotable_init(itcm_iomap, 1);
267 		/* Copy code from RAM to ITCM */
268 		start = &__sitcm_text;
269 		end   = &__eitcm_text;
270 		ram   = &__itcm_start;
271 		memcpy(start, ram, itcm_code_sz);
272 		pr_debug("CPU ITCM: copied code from %p - %p\n",
273 			 start, end);
274 		itcm_present = true;
275 	} else if (itcm_code_sz) {
276 		pr_info("CPU ITCM: %u bytes of code compiled to ITCM but no "
277 			"ITCM banks present in CPU\n", itcm_code_sz);
278 	}
279 }
280 
281 /*
282  * This creates the TCM memory pool and has to be done later,
283  * during the core_initicalls, since the allocator is not yet
284  * up and running when the first initialization runs.
285  */
setup_tcm_pool(void)286 static int __init setup_tcm_pool(void)
287 {
288 	u32 dtcm_pool_start = (u32) &__edtcm_data;
289 	u32 itcm_pool_start = (u32) &__eitcm_text;
290 	int ret;
291 
292 	/*
293 	 * Set up malloc pool, 2^2 = 4 bytes granularity since
294 	 * the TCM is sometimes just 4 KiB. NB: pages and cache
295 	 * line alignments does not matter in TCM!
296 	 */
297 	tcm_pool = gen_pool_create(2, -1);
298 
299 	pr_debug("Setting up TCM memory pool\n");
300 
301 	/* Add the rest of DTCM to the TCM pool */
302 	if (dtcm_present) {
303 		if (dtcm_pool_start < dtcm_end) {
304 			ret = gen_pool_add(tcm_pool, dtcm_pool_start,
305 					   dtcm_end - dtcm_pool_start, -1);
306 			if (ret) {
307 				pr_err("CPU DTCM: could not add DTCM " \
308 				       "remainder to pool!\n");
309 				return ret;
310 			}
311 			pr_debug("CPU DTCM: Added %08x bytes @ %08x to " \
312 				 "the TCM memory pool\n",
313 				 dtcm_end - dtcm_pool_start,
314 				 dtcm_pool_start);
315 		}
316 	}
317 
318 	/* Add the rest of ITCM to the TCM pool */
319 	if (itcm_present) {
320 		if (itcm_pool_start < itcm_end) {
321 			ret = gen_pool_add(tcm_pool, itcm_pool_start,
322 					   itcm_end - itcm_pool_start, -1);
323 			if (ret) {
324 				pr_err("CPU ITCM: could not add ITCM " \
325 				       "remainder to pool!\n");
326 				return ret;
327 			}
328 			pr_debug("CPU ITCM: Added %08x bytes @ %08x to " \
329 				 "the TCM memory pool\n",
330 				 itcm_end - itcm_pool_start,
331 				 itcm_pool_start);
332 		}
333 	}
334 	return 0;
335 }
336 
337 core_initcall(setup_tcm_pool);
338