1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2008-2009 ST-Ericsson AB
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 <asm/traps.h>
21
22 #define TCMTR_FORMAT_MASK 0xe0000000U
23
24 static struct gen_pool *tcm_pool;
25 static bool dtcm_present;
26 static bool itcm_present;
27
28 /* TCM section definitions from the linker */
29 extern char __itcm_start, __sitcm_text, __eitcm_text;
30 extern char __dtcm_start, __sdtcm_data, __edtcm_data;
31
32 /* These will be increased as we run */
33 u32 dtcm_end = DTCM_OFFSET;
34 u32 itcm_end = ITCM_OFFSET;
35
36 /*
37 * TCM memory resources
38 */
39 static struct resource dtcm_res = {
40 .name = "DTCM RAM",
41 .start = DTCM_OFFSET,
42 .end = DTCM_OFFSET,
43 .flags = IORESOURCE_MEM
44 };
45
46 static struct resource itcm_res = {
47 .name = "ITCM RAM",
48 .start = ITCM_OFFSET,
49 .end = ITCM_OFFSET,
50 .flags = IORESOURCE_MEM
51 };
52
53 static struct map_desc dtcm_iomap[] __initdata = {
54 {
55 .virtual = DTCM_OFFSET,
56 .pfn = __phys_to_pfn(DTCM_OFFSET),
57 .length = 0,
58 .type = MT_MEMORY_RW_DTCM
59 }
60 };
61
62 static struct map_desc itcm_iomap[] __initdata = {
63 {
64 .virtual = ITCM_OFFSET,
65 .pfn = __phys_to_pfn(ITCM_OFFSET),
66 .length = 0,
67 .type = MT_MEMORY_RWX_ITCM,
68 }
69 };
70
71 /*
72 * Allocate a chunk of TCM memory
73 */
74 void *tcm_alloc(size_t len)
75 {
76 unsigned long vaddr;
77
78 if (!tcm_pool)
79 return NULL;
80
81 vaddr = gen_pool_alloc(tcm_pool, len);
82 if (!vaddr)
83 return NULL;
84
85 return (void *) vaddr;
86 }
87 EXPORT_SYMBOL(tcm_alloc);
88
89 /*
90 * Free a chunk of TCM memory
91 */
92 void tcm_free(void *addr, size_t len)
93 {
94 gen_pool_free(tcm_pool, (unsigned long) addr, len);
95 }
96 EXPORT_SYMBOL(tcm_free);
97
98 bool tcm_dtcm_present(void)
99 {
100 return dtcm_present;
101 }
102 EXPORT_SYMBOL(tcm_dtcm_present);
103
104 bool tcm_itcm_present(void)
105 {
106 return itcm_present;
107 }
108 EXPORT_SYMBOL(tcm_itcm_present);
109
110 static int __init setup_tcm_bank(u8 type, u8 bank, u8 banks,
111 u32 *offset)
112 {
113 const int tcm_sizes[16] = { 0, -1, -1, 4, 8, 16, 32, 64, 128,
114 256, 512, 1024, -1, -1, -1, -1 };
115 u32 tcm_region;
116 int tcm_size;
117
118 /*
119 * If there are more than one TCM bank of this type,
120 * select the TCM bank to operate on in the TCM selection
121 * register.
122 */
123 if (banks > 1)
124 asm("mcr p15, 0, %0, c9, c2, 0"
125 : /* No output operands */
126 : "r" (bank));
127
128 /* Read the special TCM region register c9, 0 */
129 if (!type)
130 asm("mrc p15, 0, %0, c9, c1, 0"
131 : "=r" (tcm_region));
132 else
133 asm("mrc p15, 0, %0, c9, c1, 1"
134 : "=r" (tcm_region));
135
136 tcm_size = tcm_sizes[(tcm_region >> 2) & 0x0f];
137 if (tcm_size < 0) {
138 pr_err("CPU: %sTCM%d of unknown size\n",
139 type ? "I" : "D", bank);
140 return -EINVAL;
141 } else if (tcm_size > 32) {
142 pr_err("CPU: %sTCM%d larger than 32k found\n",
143 type ? "I" : "D", bank);
144 return -EINVAL;
145 } else {
146 pr_info("CPU: found %sTCM%d %dk @ %08x, %senabled\n",
147 type ? "I" : "D",
148 bank,
149 tcm_size,
150 (tcm_region & 0xfffff000U),
151 (tcm_region & 1) ? "" : "not ");
152 }
153
154 /* Not much fun you can do with a size 0 bank */
155 if (tcm_size == 0)
156 return 0;
157
158 /* Force move the TCM bank to where we want it, enable */
159 tcm_region = *offset | (tcm_region & 0x00000ffeU) | 1;
160
161 if (!type)
162 asm("mcr p15, 0, %0, c9, c1, 0"
163 : /* No output operands */
164 : "r" (tcm_region));
165 else
166 asm("mcr p15, 0, %0, c9, c1, 1"
167 : /* No output operands */
168 : "r" (tcm_region));
169
170 /* Increase offset */
171 *offset += (tcm_size << 10);
172
173 pr_info("CPU: moved %sTCM%d %dk to %08x, enabled\n",
174 type ? "I" : "D",
175 bank,
176 tcm_size,
177 (tcm_region & 0xfffff000U));
178 return 0;
179 }
180
181 /*
182 * When we are running in the non-secure world and the secure world
183 * has not explicitly given us access to the TCM we will get an
184 * undefined error when reading the TCM region register in the
185 * setup_tcm_bank function (above).
186 *
187 * There are two variants of this register read that we need to trap,
188 * the read for the data TCM and the read for the instruction TCM:
189 * c0370628: ee196f11 mrc 15, 0, r6, cr9, cr1, {0}
190 * c0370674: ee196f31 mrc 15, 0, r6, cr9, cr1, {1}
191 *
192 * Our undef hook mask explicitly matches all fields of the encoded
193 * instruction other than the destination register. The mask also
194 * only allows operand 2 to have the values 0 or 1.
195 *
196 * The undefined hook is defined as __init and __initdata, and therefore
197 * must be removed before tcm_init returns.
198 *
199 * In this particular case (MRC with ARM condition code ALways) the
200 * Thumb-2 and ARM instruction encoding are identical, so this hook
201 * will work on a Thumb-2 kernel.
202 *
203 * See A8.8.107, DDI0406C_C ARM Architecture Reference Manual, Encoding
204 * T1/A1 for the bit-by-bit details.
205 *
206 * mrc p15, 0, XX, c9, c1, 0
207 * mrc p15, 0, XX, c9, c1, 1
208 * | | | | | | | +---- opc2 0|1 = 000|001
209 * | | | | | | +------- CRm 0 = 0001
210 * | | | | | +----------- CRn 0 = 1001
211 * | | | | +--------------- Rt ? = ????
212 * | | | +------------------- opc1 0 = 000
213 * | | +----------------------- coproc 15 = 1111
214 * | +-------------------------- condition ALways = 1110
215 * +----------------------------- instruction MRC = 1110
216 *
217 * Encoding this as per A8.8.107 of DDI0406C, Encoding T1/A1, yields:
218 * 1111 1111 1111 1111 0000 1111 1101 1111 Required Mask
219 * 1110 1110 0001 1001 ???? 1111 0001 0001 mrc p15, 0, XX, c9, c1, 0
220 * 1110 1110 0001 1001 ???? 1111 0011 0001 mrc p15, 0, XX, c9, c1, 1
221 * [ ] [ ] [ ]| [ ] [ ] [ ] [ ]| +--- CRm
222 * | | | | | | | | +----- SBO
223 * | | | | | | | +------- opc2
224 * | | | | | | +----------- coproc
225 * | | | | | +---------------- Rt
226 * | | | | +--------------------- CRn
227 * | | | +------------------------- SBO
228 * | | +--------------------------- opc1
229 * | +------------------------------- instruction
230 * +------------------------------------ condition
231 */
232 #define TCM_REGION_READ_MASK 0xffff0fdf
233 #define TCM_REGION_READ_INSTR 0xee190f11
234 #define DEST_REG_SHIFT 12
235 #define DEST_REG_MASK 0xf
236
237 static int __init tcm_handler(struct pt_regs *regs, unsigned int instr)
238 {
239 regs->uregs[(instr >> DEST_REG_SHIFT) & DEST_REG_MASK] = 0;
240 regs->ARM_pc += 4;
241 return 0;
242 }
243
244 static struct undef_hook tcm_hook __initdata = {
245 .instr_mask = TCM_REGION_READ_MASK,
246 .instr_val = TCM_REGION_READ_INSTR,
247 .cpsr_mask = MODE_MASK,
248 .cpsr_val = SVC_MODE,
249 .fn = tcm_handler
250 };
251
252 /*
253 * This initializes the TCM memory
254 */
255 void __init tcm_init(void)
256 {
257 u32 tcm_status;
258 u8 dtcm_banks;
259 u8 itcm_banks;
260 size_t dtcm_code_sz = &__edtcm_data - &__sdtcm_data;
261 size_t itcm_code_sz = &__eitcm_text - &__sitcm_text;
262 char *start;
263 char *end;
264 char *ram;
265 int ret;
266 int i;
267
268 /*
269 * Prior to ARMv5 there is no TCM, and trying to read the status
270 * register will hang the processor.
271 */
272 if (cpu_architecture() < CPU_ARCH_ARMv5) {
273 if (dtcm_code_sz || itcm_code_sz)
274 pr_info("CPU TCM: %u bytes of DTCM and %u bytes of "
275 "ITCM code compiled in, but no TCM present "
276 "in pre-v5 CPU\n", dtcm_code_sz, itcm_code_sz);
277 return;
278 }
279
280 tcm_status = read_cpuid_tcmstatus();
281
282 /*
283 * This code only supports v6-compatible TCMTR implementations.
284 */
285 if (tcm_status & TCMTR_FORMAT_MASK)
286 return;
287
288 dtcm_banks = (tcm_status >> 16) & 0x03;
289 itcm_banks = (tcm_status & 0x03);
290
291 register_undef_hook(&tcm_hook);
292
293 /* Values greater than 2 for D/ITCM banks are "reserved" */
294 if (dtcm_banks > 2)
295 dtcm_banks = 0;
296 if (itcm_banks > 2)
297 itcm_banks = 0;
298
299 /* Setup DTCM if present */
300 if (dtcm_banks > 0) {
301 for (i = 0; i < dtcm_banks; i++) {
302 ret = setup_tcm_bank(0, i, dtcm_banks, &dtcm_end);
303 if (ret)
304 goto unregister;
305 }
306 /* This means you compiled more code than fits into DTCM */
307 if (dtcm_code_sz > (dtcm_end - DTCM_OFFSET)) {
308 pr_info("CPU DTCM: %u bytes of code compiled to "
309 "DTCM but only %lu bytes of DTCM present\n",
310 dtcm_code_sz, (dtcm_end - DTCM_OFFSET));
311 goto no_dtcm;
312 }
313 /*
314 * This means that the DTCM sizes were 0 or the DTCM banks
315 * were inaccessible due to TrustZone configuration.
316 */
317 if (!(dtcm_end - DTCM_OFFSET))
318 goto no_dtcm;
319 dtcm_res.end = dtcm_end - 1;
320 request_resource(&iomem_resource, &dtcm_res);
321 dtcm_iomap[0].length = dtcm_end - DTCM_OFFSET;
322 iotable_init(dtcm_iomap, 1);
323 /* Copy data from RAM to DTCM */
324 start = &__sdtcm_data;
325 end = &__edtcm_data;
326 ram = &__dtcm_start;
327 memcpy(start, ram, dtcm_code_sz);
328 pr_debug("CPU DTCM: copied data from %p - %p\n",
329 start, end);
330 dtcm_present = true;
331 } else if (dtcm_code_sz) {
332 pr_info("CPU DTCM: %u bytes of code compiled to DTCM but no "
333 "DTCM banks present in CPU\n", dtcm_code_sz);
334 }
335
336 no_dtcm:
337 /* Setup ITCM if present */
338 if (itcm_banks > 0) {
339 for (i = 0; i < itcm_banks; i++) {
340 ret = setup_tcm_bank(1, i, itcm_banks, &itcm_end);
341 if (ret)
342 goto unregister;
343 }
344 /* This means you compiled more code than fits into ITCM */
345 if (itcm_code_sz > (itcm_end - ITCM_OFFSET)) {
346 pr_info("CPU ITCM: %u bytes of code compiled to "
347 "ITCM but only %lu bytes of ITCM present\n",
348 itcm_code_sz, (itcm_end - ITCM_OFFSET));
349 goto unregister;
350 }
351 /*
352 * This means that the ITCM sizes were 0 or the ITCM banks
353 * were inaccessible due to TrustZone configuration.
354 */
355 if (!(itcm_end - ITCM_OFFSET))
356 goto unregister;
357 itcm_res.end = itcm_end - 1;
358 request_resource(&iomem_resource, &itcm_res);
359 itcm_iomap[0].length = itcm_end - ITCM_OFFSET;
360 iotable_init(itcm_iomap, 1);
361 /* Copy code from RAM to ITCM */
362 start = &__sitcm_text;
363 end = &__eitcm_text;
364 ram = &__itcm_start;
365 memcpy(start, ram, itcm_code_sz);
366 pr_debug("CPU ITCM: copied code from %p - %p\n",
367 start, end);
368 itcm_present = true;
369 } else if (itcm_code_sz) {
370 pr_info("CPU ITCM: %u bytes of code compiled to ITCM but no "
371 "ITCM banks present in CPU\n", itcm_code_sz);
372 }
373
374 unregister:
375 unregister_undef_hook(&tcm_hook);
376 }
377
378 /*
379 * This creates the TCM memory pool and has to be done later,
380 * during the core_initicalls, since the allocator is not yet
381 * up and running when the first initialization runs.
382 */
383 static int __init setup_tcm_pool(void)
384 {
385 u32 dtcm_pool_start = (u32) &__edtcm_data;
386 u32 itcm_pool_start = (u32) &__eitcm_text;
387 int ret;
388
389 /*
390 * Set up malloc pool, 2^2 = 4 bytes granularity since
391 * the TCM is sometimes just 4 KiB. NB: pages and cache
392 * line alignments does not matter in TCM!
393 */
394 tcm_pool = gen_pool_create(2, -1);
395
396 pr_debug("Setting up TCM memory pool\n");
397
398 /* Add the rest of DTCM to the TCM pool */
399 if (dtcm_present) {
400 if (dtcm_pool_start < dtcm_end) {
401 ret = gen_pool_add(tcm_pool, dtcm_pool_start,
402 dtcm_end - dtcm_pool_start, -1);
403 if (ret) {
404 pr_err("CPU DTCM: could not add DTCM " \
405 "remainder to pool!\n");
406 return ret;
407 }
408 pr_debug("CPU DTCM: Added %08x bytes @ %08x to " \
409 "the TCM memory pool\n",
410 dtcm_end - dtcm_pool_start,
411 dtcm_pool_start);
412 }
413 }
414
415 /* Add the rest of ITCM to the TCM pool */
416 if (itcm_present) {
417 if (itcm_pool_start < itcm_end) {
418 ret = gen_pool_add(tcm_pool, itcm_pool_start,
419 itcm_end - itcm_pool_start, -1);
420 if (ret) {
421 pr_err("CPU ITCM: could not add ITCM " \
422 "remainder to pool!\n");
423 return ret;
424 }
425 pr_debug("CPU ITCM: Added %08x bytes @ %08x to " \
426 "the TCM memory pool\n",
427 itcm_end - itcm_pool_start,
428 itcm_pool_start);
429 }
430 }
431 return 0;
432 }
433
434 core_initcall(setup_tcm_pool);