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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/page.h>
19#include <asm/system_info.h>
20#include <asm/traps.h>
21#include <asm/tcm.h>
22
23#define TCMTR_FORMAT_MASK 0xe0000000U
24
25static struct gen_pool *tcm_pool;
26static bool dtcm_present;
27static bool itcm_present;
28
29/* TCM section definitions from the linker */
30extern char __itcm_start, __sitcm_text, __eitcm_text;
31extern char __dtcm_start, __sdtcm_data, __edtcm_data;
32
33/* These will be increased as we run */
34static u32 dtcm_end = DTCM_OFFSET;
35static u32 itcm_end = ITCM_OFFSET;
36
37/*
38 * TCM memory resources
39 */
40static struct resource dtcm_res = {
41 .name = "DTCM RAM",
42 .start = DTCM_OFFSET,
43 .end = DTCM_OFFSET,
44 .flags = IORESOURCE_MEM
45};
46
47static struct resource itcm_res = {
48 .name = "ITCM RAM",
49 .start = ITCM_OFFSET,
50 .end = ITCM_OFFSET,
51 .flags = IORESOURCE_MEM
52};
53
54static struct map_desc dtcm_iomap[] __initdata = {
55 {
56 .virtual = DTCM_OFFSET,
57 .pfn = __phys_to_pfn(DTCM_OFFSET),
58 .length = 0,
59 .type = MT_MEMORY_RW_DTCM
60 }
61};
62
63static struct map_desc itcm_iomap[] __initdata = {
64 {
65 .virtual = ITCM_OFFSET,
66 .pfn = __phys_to_pfn(ITCM_OFFSET),
67 .length = 0,
68 .type = MT_MEMORY_RWX_ITCM,
69 }
70};
71
72/*
73 * Allocate a chunk of TCM memory
74 */
75void *tcm_alloc(size_t len)
76{
77 unsigned long vaddr;
78
79 if (!tcm_pool)
80 return NULL;
81
82 vaddr = gen_pool_alloc(pool: tcm_pool, size: len);
83 if (!vaddr)
84 return NULL;
85
86 return (void *) vaddr;
87}
88EXPORT_SYMBOL(tcm_alloc);
89
90/*
91 * Free a chunk of TCM memory
92 */
93void tcm_free(void *addr, size_t len)
94{
95 gen_pool_free(pool: tcm_pool, addr: (unsigned long) addr, size: len);
96}
97EXPORT_SYMBOL(tcm_free);
98
99bool tcm_dtcm_present(void)
100{
101 return dtcm_present;
102}
103EXPORT_SYMBOL(tcm_dtcm_present);
104
105bool tcm_itcm_present(void)
106{
107 return itcm_present;
108}
109EXPORT_SYMBOL(tcm_itcm_present);
110
111static int __init setup_tcm_bank(u8 type, u8 bank, u8 banks,
112 u32 *offset)
113{
114 const int tcm_sizes[16] = { 0, -1, -1, 4, 8, 16, 32, 64, 128,
115 256, 512, 1024, -1, -1, -1, -1 };
116 u32 tcm_region;
117 int tcm_size;
118
119 /*
120 * If there are more than one TCM bank of this type,
121 * select the TCM bank to operate on in the TCM selection
122 * register.
123 */
124 if (banks > 1)
125 asm("mcr p15, 0, %0, c9, c2, 0"
126 : /* No output operands */
127 : "r" (bank));
128
129 /* Read the special TCM region register c9, 0 */
130 if (!type)
131 asm("mrc p15, 0, %0, c9, c1, 0"
132 : "=r" (tcm_region));
133 else
134 asm("mrc p15, 0, %0, c9, c1, 1"
135 : "=r" (tcm_region));
136
137 tcm_size = tcm_sizes[(tcm_region >> 2) & 0x0f];
138 if (tcm_size < 0) {
139 pr_err("CPU: %sTCM%d of unknown size\n",
140 type ? "I" : "D", bank);
141 return -EINVAL;
142 } else if (tcm_size > 32) {
143 pr_err("CPU: %sTCM%d larger than 32k found\n",
144 type ? "I" : "D", bank);
145 return -EINVAL;
146 } else {
147 pr_info("CPU: found %sTCM%d %dk @ %08x, %senabled\n",
148 type ? "I" : "D",
149 bank,
150 tcm_size,
151 (tcm_region & 0xfffff000U),
152 (tcm_region & 1) ? "" : "not ");
153 }
154
155 /* Not much fun you can do with a size 0 bank */
156 if (tcm_size == 0)
157 return 0;
158
159 /* Force move the TCM bank to where we want it, enable */
160 tcm_region = *offset | (tcm_region & 0x00000ffeU) | 1;
161
162 if (!type)
163 asm("mcr p15, 0, %0, c9, c1, 0"
164 : /* No output operands */
165 : "r" (tcm_region));
166 else
167 asm("mcr p15, 0, %0, c9, c1, 1"
168 : /* No output operands */
169 : "r" (tcm_region));
170
171 /* Increase offset */
172 *offset += (tcm_size << 10);
173
174 pr_info("CPU: moved %sTCM%d %dk to %08x, enabled\n",
175 type ? "I" : "D",
176 bank,
177 tcm_size,
178 (tcm_region & 0xfffff000U));
179 return 0;
180}
181
182/*
183 * When we are running in the non-secure world and the secure world
184 * has not explicitly given us access to the TCM we will get an
185 * undefined error when reading the TCM region register in the
186 * setup_tcm_bank function (above).
187 *
188 * There are two variants of this register read that we need to trap,
189 * the read for the data TCM and the read for the instruction TCM:
190 * c0370628: ee196f11 mrc 15, 0, r6, cr9, cr1, {0}
191 * c0370674: ee196f31 mrc 15, 0, r6, cr9, cr1, {1}
192 *
193 * Our undef hook mask explicitly matches all fields of the encoded
194 * instruction other than the destination register. The mask also
195 * only allows operand 2 to have the values 0 or 1.
196 *
197 * The undefined hook is defined as __init and __initdata, and therefore
198 * must be removed before tcm_init returns.
199 *
200 * In this particular case (MRC with ARM condition code ALways) the
201 * Thumb-2 and ARM instruction encoding are identical, so this hook
202 * will work on a Thumb-2 kernel.
203 *
204 * See A8.8.107, DDI0406C_C ARM Architecture Reference Manual, Encoding
205 * T1/A1 for the bit-by-bit details.
206 *
207 * mrc p15, 0, XX, c9, c1, 0
208 * mrc p15, 0, XX, c9, c1, 1
209 * | | | | | | | +---- opc2 0|1 = 000|001
210 * | | | | | | +------- CRm 0 = 0001
211 * | | | | | +----------- CRn 0 = 1001
212 * | | | | +--------------- Rt ? = ????
213 * | | | +------------------- opc1 0 = 000
214 * | | +----------------------- coproc 15 = 1111
215 * | +-------------------------- condition ALways = 1110
216 * +----------------------------- instruction MRC = 1110
217 *
218 * Encoding this as per A8.8.107 of DDI0406C, Encoding T1/A1, yields:
219 * 1111 1111 1111 1111 0000 1111 1101 1111 Required Mask
220 * 1110 1110 0001 1001 ???? 1111 0001 0001 mrc p15, 0, XX, c9, c1, 0
221 * 1110 1110 0001 1001 ???? 1111 0011 0001 mrc p15, 0, XX, c9, c1, 1
222 * [ ] [ ] [ ]| [ ] [ ] [ ] [ ]| +--- CRm
223 * | | | | | | | | +----- SBO
224 * | | | | | | | +------- opc2
225 * | | | | | | +----------- coproc
226 * | | | | | +---------------- Rt
227 * | | | | +--------------------- CRn
228 * | | | +------------------------- SBO
229 * | | +--------------------------- opc1
230 * | +------------------------------- instruction
231 * +------------------------------------ condition
232 */
233#define TCM_REGION_READ_MASK 0xffff0fdf
234#define TCM_REGION_READ_INSTR 0xee190f11
235#define DEST_REG_SHIFT 12
236#define DEST_REG_MASK 0xf
237
238static int __init tcm_handler(struct pt_regs *regs, unsigned int instr)
239{
240 regs->uregs[(instr >> DEST_REG_SHIFT) & DEST_REG_MASK] = 0;
241 regs->ARM_pc += 4;
242 return 0;
243}
244
245static struct undef_hook tcm_hook __initdata = {
246 .instr_mask = TCM_REGION_READ_MASK,
247 .instr_val = TCM_REGION_READ_INSTR,
248 .cpsr_mask = MODE_MASK,
249 .cpsr_val = SVC_MODE,
250 .fn = tcm_handler
251};
252
253/*
254 * This initializes the TCM memory
255 */
256void __init tcm_init(void)
257{
258 u32 tcm_status;
259 u8 dtcm_banks;
260 u8 itcm_banks;
261 size_t dtcm_code_sz = &__edtcm_data - &__sdtcm_data;
262 size_t itcm_code_sz = &__eitcm_text - &__sitcm_text;
263 char *start;
264 char *end;
265 char *ram;
266 int ret;
267 int i;
268
269 /*
270 * Prior to ARMv5 there is no TCM, and trying to read the status
271 * register will hang the processor.
272 */
273 if (cpu_architecture() < CPU_ARCH_ARMv5) {
274 if (dtcm_code_sz || itcm_code_sz)
275 pr_info("CPU TCM: %u bytes of DTCM and %u bytes of "
276 "ITCM code compiled in, but no TCM present "
277 "in pre-v5 CPU\n", dtcm_code_sz, itcm_code_sz);
278 return;
279 }
280
281 tcm_status = read_cpuid_tcmstatus();
282
283 /*
284 * This code only supports v6-compatible TCMTR implementations.
285 */
286 if (tcm_status & TCMTR_FORMAT_MASK)
287 return;
288
289 dtcm_banks = (tcm_status >> 16) & 0x03;
290 itcm_banks = (tcm_status & 0x03);
291
292 register_undef_hook(&tcm_hook);
293
294 /* Values greater than 2 for D/ITCM banks are "reserved" */
295 if (dtcm_banks > 2)
296 dtcm_banks = 0;
297 if (itcm_banks > 2)
298 itcm_banks = 0;
299
300 /* Setup DTCM if present */
301 if (dtcm_banks > 0) {
302 for (i = 0; i < dtcm_banks; i++) {
303 ret = setup_tcm_bank(type: 0, bank: i, banks: dtcm_banks, offset: &dtcm_end);
304 if (ret)
305 goto unregister;
306 }
307 /* This means you compiled more code than fits into DTCM */
308 if (dtcm_code_sz > (dtcm_end - DTCM_OFFSET)) {
309 pr_info("CPU DTCM: %u bytes of code compiled to "
310 "DTCM but only %lu bytes of DTCM present\n",
311 dtcm_code_sz, (dtcm_end - DTCM_OFFSET));
312 goto no_dtcm;
313 }
314 /*
315 * This means that the DTCM sizes were 0 or the DTCM banks
316 * were inaccessible due to TrustZone configuration.
317 */
318 if (!(dtcm_end - DTCM_OFFSET))
319 goto no_dtcm;
320 dtcm_res.end = dtcm_end - 1;
321 request_resource(root: &iomem_resource, new: &dtcm_res);
322 dtcm_iomap[0].length = dtcm_end - DTCM_OFFSET;
323 iotable_init(dtcm_iomap, 1);
324 /* Copy data from RAM to DTCM */
325 start = &__sdtcm_data;
326 end = &__edtcm_data;
327 ram = &__dtcm_start;
328 memcpy(start, ram, dtcm_code_sz);
329 pr_debug("CPU DTCM: copied data from %p - %p\n",
330 start, end);
331 dtcm_present = true;
332 } else if (dtcm_code_sz) {
333 pr_info("CPU DTCM: %u bytes of code compiled to DTCM but no "
334 "DTCM banks present in CPU\n", dtcm_code_sz);
335 }
336
337no_dtcm:
338 /* Setup ITCM if present */
339 if (itcm_banks > 0) {
340 for (i = 0; i < itcm_banks; i++) {
341 ret = setup_tcm_bank(type: 1, bank: i, banks: itcm_banks, offset: &itcm_end);
342 if (ret)
343 goto unregister;
344 }
345 /* This means you compiled more code than fits into ITCM */
346 if (itcm_code_sz > (itcm_end - ITCM_OFFSET)) {
347 pr_info("CPU ITCM: %u bytes of code compiled to "
348 "ITCM but only %lu bytes of ITCM present\n",
349 itcm_code_sz, (itcm_end - ITCM_OFFSET));
350 goto unregister;
351 }
352 /*
353 * This means that the ITCM sizes were 0 or the ITCM banks
354 * were inaccessible due to TrustZone configuration.
355 */
356 if (!(itcm_end - ITCM_OFFSET))
357 goto unregister;
358 itcm_res.end = itcm_end - 1;
359 request_resource(root: &iomem_resource, new: &itcm_res);
360 itcm_iomap[0].length = itcm_end - ITCM_OFFSET;
361 iotable_init(itcm_iomap, 1);
362 /* Copy code from RAM to ITCM */
363 start = &__sitcm_text;
364 end = &__eitcm_text;
365 ram = &__itcm_start;
366 memcpy(start, ram, itcm_code_sz);
367 pr_debug("CPU ITCM: copied code from %p - %p\n",
368 start, end);
369 itcm_present = true;
370 } else if (itcm_code_sz) {
371 pr_info("CPU ITCM: %u bytes of code compiled to ITCM but no "
372 "ITCM banks present in CPU\n", itcm_code_sz);
373 }
374
375unregister:
376 unregister_undef_hook(&tcm_hook);
377}
378
379/*
380 * This creates the TCM memory pool and has to be done later,
381 * during the core_initicalls, since the allocator is not yet
382 * up and running when the first initialization runs.
383 */
384static int __init setup_tcm_pool(void)
385{
386 u32 dtcm_pool_start = (u32) &__edtcm_data;
387 u32 itcm_pool_start = (u32) &__eitcm_text;
388 int ret;
389
390 /*
391 * Set up malloc pool, 2^2 = 4 bytes granularity since
392 * the TCM is sometimes just 4 KiB. NB: pages and cache
393 * line alignments does not matter in TCM!
394 */
395 tcm_pool = gen_pool_create(2, -1);
396
397 pr_debug("Setting up TCM memory pool\n");
398
399 /* Add the rest of DTCM to the TCM pool */
400 if (dtcm_present) {
401 if (dtcm_pool_start < dtcm_end) {
402 ret = gen_pool_add(pool: tcm_pool, addr: dtcm_pool_start,
403 size: dtcm_end - dtcm_pool_start, nid: -1);
404 if (ret) {
405 pr_err("CPU DTCM: could not add DTCM " \
406 "remainder to pool!\n");
407 return ret;
408 }
409 pr_debug("CPU DTCM: Added %08x bytes @ %08x to " \
410 "the TCM memory pool\n",
411 dtcm_end - dtcm_pool_start,
412 dtcm_pool_start);
413 }
414 }
415
416 /* Add the rest of ITCM to the TCM pool */
417 if (itcm_present) {
418 if (itcm_pool_start < itcm_end) {
419 ret = gen_pool_add(pool: tcm_pool, addr: itcm_pool_start,
420 size: itcm_end - itcm_pool_start, nid: -1);
421 if (ret) {
422 pr_err("CPU ITCM: could not add ITCM " \
423 "remainder to pool!\n");
424 return ret;
425 }
426 pr_debug("CPU ITCM: Added %08x bytes @ %08x to " \
427 "the TCM memory pool\n",
428 itcm_end - itcm_pool_start,
429 itcm_pool_start);
430 }
431 }
432 return 0;
433}
434
435core_initcall(setup_tcm_pool);
436

source code of linux/arch/arm/kernel/tcm.c