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