1 /*
2  * TI AM33XX SRAM EMIF Driver
3  *
4  * Copyright (C) 2016-2017 Texas Instruments Inc.
5  *	Dave Gerlach
6  *
7  * This program is free software; you can redistribute it and/or
8  * modify it under the terms of the GNU General Public License
9  * version 2 as published by the Free Software Foundation.
10  *
11  * This program is distributed in the hope that it will be useful,
12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14  * GNU General Public License for more details.
15  */
16 
17 #include <linux/err.h>
18 #include <linux/genalloc.h>
19 #include <linux/io.h>
20 #include <linux/kernel.h>
21 #include <linux/module.h>
22 #include <linux/of.h>
23 #include <linux/of_platform.h>
24 #include <linux/platform_device.h>
25 #include <linux/sram.h>
26 #include <linux/ti-emif-sram.h>
27 
28 #include "emif.h"
29 
30 #define TI_EMIF_SRAM_SYMBOL_OFFSET(sym) ((unsigned long)(sym) - \
31 					 (unsigned long)&ti_emif_sram)
32 
33 #define EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES		0x00a0
34 
35 struct ti_emif_data {
36 	phys_addr_t ti_emif_sram_phys;
37 	phys_addr_t ti_emif_sram_data_phys;
38 	unsigned long ti_emif_sram_virt;
39 	unsigned long ti_emif_sram_data_virt;
40 	struct gen_pool *sram_pool_code;
41 	struct gen_pool	*sram_pool_data;
42 	struct ti_emif_pm_data pm_data;
43 	struct ti_emif_pm_functions pm_functions;
44 };
45 
46 static struct ti_emif_data *emif_instance;
47 
sram_suspend_address(struct ti_emif_data * emif_data,unsigned long addr)48 static u32 sram_suspend_address(struct ti_emif_data *emif_data,
49 				unsigned long addr)
50 {
51 	return (emif_data->ti_emif_sram_virt +
52 		TI_EMIF_SRAM_SYMBOL_OFFSET(addr));
53 }
54 
sram_resume_address(struct ti_emif_data * emif_data,unsigned long addr)55 static phys_addr_t sram_resume_address(struct ti_emif_data *emif_data,
56 				       unsigned long addr)
57 {
58 	return ((unsigned long)emif_data->ti_emif_sram_phys +
59 		TI_EMIF_SRAM_SYMBOL_OFFSET(addr));
60 }
61 
ti_emif_free_sram(struct ti_emif_data * emif_data)62 static void ti_emif_free_sram(struct ti_emif_data *emif_data)
63 {
64 	gen_pool_free(emif_data->sram_pool_code, emif_data->ti_emif_sram_virt,
65 		      ti_emif_sram_sz);
66 	gen_pool_free(emif_data->sram_pool_data,
67 		      emif_data->ti_emif_sram_data_virt,
68 		      sizeof(struct emif_regs_amx3));
69 }
70 
ti_emif_alloc_sram(struct device * dev,struct ti_emif_data * emif_data)71 static int ti_emif_alloc_sram(struct device *dev,
72 			      struct ti_emif_data *emif_data)
73 {
74 	struct device_node *np = dev->of_node;
75 	int ret;
76 
77 	emif_data->sram_pool_code = of_gen_pool_get(np, "sram", 0);
78 	if (!emif_data->sram_pool_code) {
79 		dev_err(dev, "Unable to get sram pool for ocmcram code\n");
80 		return -ENODEV;
81 	}
82 
83 	emif_data->ti_emif_sram_virt =
84 			gen_pool_alloc(emif_data->sram_pool_code,
85 				       ti_emif_sram_sz);
86 	if (!emif_data->ti_emif_sram_virt) {
87 		dev_err(dev, "Unable to allocate code memory from ocmcram\n");
88 		return -ENOMEM;
89 	}
90 
91 	/* Save physical address to calculate resume offset during pm init */
92 	emif_data->ti_emif_sram_phys =
93 			gen_pool_virt_to_phys(emif_data->sram_pool_code,
94 					      emif_data->ti_emif_sram_virt);
95 
96 	/* Get sram pool for data section and allocate space */
97 	emif_data->sram_pool_data = of_gen_pool_get(np, "sram", 1);
98 	if (!emif_data->sram_pool_data) {
99 		dev_err(dev, "Unable to get sram pool for ocmcram data\n");
100 		ret = -ENODEV;
101 		goto err_free_sram_code;
102 	}
103 
104 	emif_data->ti_emif_sram_data_virt =
105 				gen_pool_alloc(emif_data->sram_pool_data,
106 					       sizeof(struct emif_regs_amx3));
107 	if (!emif_data->ti_emif_sram_data_virt) {
108 		dev_err(dev, "Unable to allocate data memory from ocmcram\n");
109 		ret = -ENOMEM;
110 		goto err_free_sram_code;
111 	}
112 
113 	/* Save physical address to calculate resume offset during pm init */
114 	emif_data->ti_emif_sram_data_phys =
115 		gen_pool_virt_to_phys(emif_data->sram_pool_data,
116 				      emif_data->ti_emif_sram_data_virt);
117 	/*
118 	 * These functions are called during suspend path while MMU is
119 	 * still on so add virtual base to offset for absolute address
120 	 */
121 	emif_data->pm_functions.save_context =
122 		sram_suspend_address(emif_data,
123 				     (unsigned long)ti_emif_save_context);
124 	emif_data->pm_functions.enter_sr =
125 		sram_suspend_address(emif_data,
126 				     (unsigned long)ti_emif_enter_sr);
127 	emif_data->pm_functions.abort_sr =
128 		sram_suspend_address(emif_data,
129 				     (unsigned long)ti_emif_abort_sr);
130 
131 	/*
132 	 * These are called during resume path when MMU is not enabled
133 	 * so physical address is used instead
134 	 */
135 	emif_data->pm_functions.restore_context =
136 		sram_resume_address(emif_data,
137 				    (unsigned long)ti_emif_restore_context);
138 	emif_data->pm_functions.exit_sr =
139 		sram_resume_address(emif_data,
140 				    (unsigned long)ti_emif_exit_sr);
141 
142 	emif_data->pm_data.regs_virt =
143 		(struct emif_regs_amx3 *)emif_data->ti_emif_sram_data_virt;
144 	emif_data->pm_data.regs_phys = emif_data->ti_emif_sram_data_phys;
145 
146 	return 0;
147 
148 err_free_sram_code:
149 	gen_pool_free(emif_data->sram_pool_code, emif_data->ti_emif_sram_virt,
150 		      ti_emif_sram_sz);
151 	return ret;
152 }
153 
ti_emif_push_sram(struct device * dev,struct ti_emif_data * emif_data)154 static int ti_emif_push_sram(struct device *dev, struct ti_emif_data *emif_data)
155 {
156 	void *copy_addr;
157 	u32 data_addr;
158 
159 	copy_addr = sram_exec_copy(emif_data->sram_pool_code,
160 				   (void *)emif_data->ti_emif_sram_virt,
161 				   &ti_emif_sram, ti_emif_sram_sz);
162 	if (!copy_addr) {
163 		dev_err(dev, "Cannot copy emif code to sram\n");
164 		return -ENODEV;
165 	}
166 
167 	data_addr = sram_suspend_address(emif_data,
168 					 (unsigned long)&ti_emif_pm_sram_data);
169 	copy_addr = sram_exec_copy(emif_data->sram_pool_code,
170 				   (void *)data_addr,
171 				   &emif_data->pm_data,
172 				   sizeof(emif_data->pm_data));
173 	if (!copy_addr) {
174 		dev_err(dev, "Cannot copy emif data to code sram\n");
175 		return -ENODEV;
176 	}
177 
178 	return 0;
179 }
180 
181 /*
182  * Due to Usage Note 3.1.2 "DDR3: JEDEC Compliance for Maximum
183  * Self-Refresh Command Limit" found in AM335x Silicon Errata
184  * (Document SPRZ360F Revised November 2013) we must configure
185  * the self refresh delay timer to 0xA (8192 cycles) to avoid
186  * generating too many refresh command from the EMIF.
187  */
ti_emif_configure_sr_delay(struct ti_emif_data * emif_data)188 static void ti_emif_configure_sr_delay(struct ti_emif_data *emif_data)
189 {
190 	writel(EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES,
191 	       (emif_data->pm_data.ti_emif_base_addr_virt +
192 		EMIF_POWER_MANAGEMENT_CONTROL));
193 
194 	writel(EMIF_POWER_MGMT_WAIT_SELF_REFRESH_8192_CYCLES,
195 	       (emif_data->pm_data.ti_emif_base_addr_virt +
196 		EMIF_POWER_MANAGEMENT_CTRL_SHDW));
197 }
198 
199 /**
200  * ti_emif_copy_pm_function_table - copy mapping of pm funcs in sram
201  * @sram_pool: pointer to struct gen_pool where dst resides
202  * @dst: void * to address that table should be copied
203  *
204  * Returns 0 if success other error code if table is not available
205  */
ti_emif_copy_pm_function_table(struct gen_pool * sram_pool,void * dst)206 int ti_emif_copy_pm_function_table(struct gen_pool *sram_pool, void *dst)
207 {
208 	void *copy_addr;
209 
210 	if (!emif_instance)
211 		return -ENODEV;
212 
213 	copy_addr = sram_exec_copy(sram_pool, dst,
214 				   &emif_instance->pm_functions,
215 				   sizeof(emif_instance->pm_functions));
216 	if (!copy_addr)
217 		return -ENODEV;
218 
219 	return 0;
220 }
221 EXPORT_SYMBOL_GPL(ti_emif_copy_pm_function_table);
222 
223 /**
224  * ti_emif_get_mem_type - return type for memory type in use
225  *
226  * Returns memory type value read from EMIF or error code if fails
227  */
ti_emif_get_mem_type(void)228 int ti_emif_get_mem_type(void)
229 {
230 	unsigned long temp;
231 
232 	if (!emif_instance)
233 		return -ENODEV;
234 
235 	temp = readl(emif_instance->pm_data.ti_emif_base_addr_virt +
236 		     EMIF_SDRAM_CONFIG);
237 
238 	temp = (temp & SDRAM_TYPE_MASK) >> SDRAM_TYPE_SHIFT;
239 	return temp;
240 }
241 EXPORT_SYMBOL_GPL(ti_emif_get_mem_type);
242 
243 static const struct of_device_id ti_emif_of_match[] = {
244 	{ .compatible = "ti,emif-am3352", .data =
245 					(void *)EMIF_SRAM_AM33_REG_LAYOUT, },
246 	{ .compatible = "ti,emif-am4372", .data =
247 					(void *)EMIF_SRAM_AM43_REG_LAYOUT, },
248 	{},
249 };
250 MODULE_DEVICE_TABLE(of, ti_emif_of_match);
251 
252 #ifdef CONFIG_PM_SLEEP
ti_emif_resume(struct device * dev)253 static int ti_emif_resume(struct device *dev)
254 {
255 	unsigned long tmp =
256 			__raw_readl((void *)emif_instance->ti_emif_sram_virt);
257 
258 	/*
259 	 * Check to see if what we are copying is already present in the
260 	 * first byte at the destination, only copy if it is not which
261 	 * indicates we have lost context and sram no longer contains
262 	 * the PM code
263 	 */
264 	if (tmp != ti_emif_sram)
265 		ti_emif_push_sram(dev, emif_instance);
266 
267 	return 0;
268 }
269 
ti_emif_suspend(struct device * dev)270 static int ti_emif_suspend(struct device *dev)
271 {
272 	/*
273 	 * The contents will be present in DDR hence no need to
274 	 * explicitly save
275 	 */
276 	return 0;
277 }
278 #endif /* CONFIG_PM_SLEEP */
279 
ti_emif_probe(struct platform_device * pdev)280 static int ti_emif_probe(struct platform_device *pdev)
281 {
282 	int ret;
283 	struct resource *res;
284 	struct device *dev = &pdev->dev;
285 	const struct of_device_id *match;
286 	struct ti_emif_data *emif_data;
287 
288 	emif_data = devm_kzalloc(dev, sizeof(*emif_data), GFP_KERNEL);
289 	if (!emif_data)
290 		return -ENOMEM;
291 
292 	match = of_match_device(ti_emif_of_match, &pdev->dev);
293 	if (!match)
294 		return -ENODEV;
295 
296 	emif_data->pm_data.ti_emif_sram_config = (unsigned long)match->data;
297 
298 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
299 	emif_data->pm_data.ti_emif_base_addr_virt = devm_ioremap_resource(dev,
300 									  res);
301 	if (IS_ERR(emif_data->pm_data.ti_emif_base_addr_virt)) {
302 		ret = PTR_ERR(emif_data->pm_data.ti_emif_base_addr_virt);
303 		return ret;
304 	}
305 
306 	emif_data->pm_data.ti_emif_base_addr_phys = res->start;
307 
308 	ti_emif_configure_sr_delay(emif_data);
309 
310 	ret = ti_emif_alloc_sram(dev, emif_data);
311 	if (ret)
312 		return ret;
313 
314 	ret = ti_emif_push_sram(dev, emif_data);
315 	if (ret)
316 		goto fail_free_sram;
317 
318 	emif_instance = emif_data;
319 
320 	return 0;
321 
322 fail_free_sram:
323 	ti_emif_free_sram(emif_data);
324 
325 	return ret;
326 }
327 
ti_emif_remove(struct platform_device * pdev)328 static int ti_emif_remove(struct platform_device *pdev)
329 {
330 	struct ti_emif_data *emif_data = emif_instance;
331 
332 	emif_instance = NULL;
333 
334 	ti_emif_free_sram(emif_data);
335 
336 	return 0;
337 }
338 
339 static const struct dev_pm_ops ti_emif_pm_ops = {
340 	SET_SYSTEM_SLEEP_PM_OPS(ti_emif_suspend, ti_emif_resume)
341 };
342 
343 static struct platform_driver ti_emif_driver = {
344 	.probe = ti_emif_probe,
345 	.remove = ti_emif_remove,
346 	.driver = {
347 		.name = KBUILD_MODNAME,
348 		.of_match_table = of_match_ptr(ti_emif_of_match),
349 		.pm = &ti_emif_pm_ops,
350 	},
351 };
352 module_platform_driver(ti_emif_driver);
353 
354 MODULE_AUTHOR("Dave Gerlach <d-gerlach@ti.com>");
355 MODULE_DESCRIPTION("Texas Instruments SRAM EMIF driver");
356 MODULE_LICENSE("GPL v2");
357