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