1 /* 2 * TI AEMIF driver 3 * 4 * Copyright (C) 2010 - 2013 Texas Instruments Incorporated. http://www.ti.com/ 5 * 6 * Authors: 7 * Murali Karicheri <m-karicheri2@ti.com> 8 * Ivan Khoronzhuk <ivan.khoronzhuk@ti.com> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 as 12 * published by the Free Software Foundation. 13 */ 14 15 #include <linux/clk.h> 16 #include <linux/err.h> 17 #include <linux/io.h> 18 #include <linux/kernel.h> 19 #include <linux/module.h> 20 #include <linux/of.h> 21 #include <linux/of_platform.h> 22 #include <linux/platform_device.h> 23 #include <linux/platform_data/ti-aemif.h> 24 25 #define TA_SHIFT 2 26 #define RHOLD_SHIFT 4 27 #define RSTROBE_SHIFT 7 28 #define RSETUP_SHIFT 13 29 #define WHOLD_SHIFT 17 30 #define WSTROBE_SHIFT 20 31 #define WSETUP_SHIFT 26 32 #define EW_SHIFT 30 33 #define SS_SHIFT 31 34 35 #define TA(x) ((x) << TA_SHIFT) 36 #define RHOLD(x) ((x) << RHOLD_SHIFT) 37 #define RSTROBE(x) ((x) << RSTROBE_SHIFT) 38 #define RSETUP(x) ((x) << RSETUP_SHIFT) 39 #define WHOLD(x) ((x) << WHOLD_SHIFT) 40 #define WSTROBE(x) ((x) << WSTROBE_SHIFT) 41 #define WSETUP(x) ((x) << WSETUP_SHIFT) 42 #define EW(x) ((x) << EW_SHIFT) 43 #define SS(x) ((x) << SS_SHIFT) 44 45 #define ASIZE_MAX 0x1 46 #define TA_MAX 0x3 47 #define RHOLD_MAX 0x7 48 #define RSTROBE_MAX 0x3f 49 #define RSETUP_MAX 0xf 50 #define WHOLD_MAX 0x7 51 #define WSTROBE_MAX 0x3f 52 #define WSETUP_MAX 0xf 53 #define EW_MAX 0x1 54 #define SS_MAX 0x1 55 #define NUM_CS 4 56 57 #define TA_VAL(x) (((x) & TA(TA_MAX)) >> TA_SHIFT) 58 #define RHOLD_VAL(x) (((x) & RHOLD(RHOLD_MAX)) >> RHOLD_SHIFT) 59 #define RSTROBE_VAL(x) (((x) & RSTROBE(RSTROBE_MAX)) >> RSTROBE_SHIFT) 60 #define RSETUP_VAL(x) (((x) & RSETUP(RSETUP_MAX)) >> RSETUP_SHIFT) 61 #define WHOLD_VAL(x) (((x) & WHOLD(WHOLD_MAX)) >> WHOLD_SHIFT) 62 #define WSTROBE_VAL(x) (((x) & WSTROBE(WSTROBE_MAX)) >> WSTROBE_SHIFT) 63 #define WSETUP_VAL(x) (((x) & WSETUP(WSETUP_MAX)) >> WSETUP_SHIFT) 64 #define EW_VAL(x) (((x) & EW(EW_MAX)) >> EW_SHIFT) 65 #define SS_VAL(x) (((x) & SS(SS_MAX)) >> SS_SHIFT) 66 67 #define NRCSR_OFFSET 0x00 68 #define AWCCR_OFFSET 0x04 69 #define A1CR_OFFSET 0x10 70 71 #define ACR_ASIZE_MASK 0x3 72 #define ACR_EW_MASK BIT(30) 73 #define ACR_SS_MASK BIT(31) 74 #define ASIZE_16BIT 1 75 76 #define CONFIG_MASK (TA(TA_MAX) | \ 77 RHOLD(RHOLD_MAX) | \ 78 RSTROBE(RSTROBE_MAX) | \ 79 RSETUP(RSETUP_MAX) | \ 80 WHOLD(WHOLD_MAX) | \ 81 WSTROBE(WSTROBE_MAX) | \ 82 WSETUP(WSETUP_MAX) | \ 83 EW(EW_MAX) | SS(SS_MAX) | \ 84 ASIZE_MAX) 85 86 /** 87 * struct aemif_cs_data: structure to hold cs parameters 88 * @cs: chip-select number 89 * @wstrobe: write strobe width, ns 90 * @rstrobe: read strobe width, ns 91 * @wsetup: write setup width, ns 92 * @whold: write hold width, ns 93 * @rsetup: read setup width, ns 94 * @rhold: read hold width, ns 95 * @ta: minimum turn around time, ns 96 * @enable_ss: enable/disable select strobe mode 97 * @enable_ew: enable/disable extended wait mode 98 * @asize: width of the asynchronous device's data bus 99 */ 100 struct aemif_cs_data { 101 u8 cs; 102 u16 wstrobe; 103 u16 rstrobe; 104 u8 wsetup; 105 u8 whold; 106 u8 rsetup; 107 u8 rhold; 108 u8 ta; 109 u8 enable_ss; 110 u8 enable_ew; 111 u8 asize; 112 }; 113 114 /** 115 * struct aemif_device: structure to hold device data 116 * @base: base address of AEMIF registers 117 * @clk: source clock 118 * @clk_rate: clock's rate in kHz 119 * @num_cs: number of assigned chip-selects 120 * @cs_offset: start number of cs nodes 121 * @cs_data: array of chip-select settings 122 */ 123 struct aemif_device { 124 void __iomem *base; 125 struct clk *clk; 126 unsigned long clk_rate; 127 u8 num_cs; 128 int cs_offset; 129 struct aemif_cs_data cs_data[NUM_CS]; 130 }; 131 132 /** 133 * aemif_calc_rate - calculate timing data. 134 * @pdev: platform device to calculate for 135 * @wanted: The cycle time needed in nanoseconds. 136 * @clk: The input clock rate in kHz. 137 * @max: The maximum divider value that can be programmed. 138 * 139 * On success, returns the calculated timing value minus 1 for easy 140 * programming into AEMIF timing registers, else negative errno. 141 */ 142 static int aemif_calc_rate(struct platform_device *pdev, int wanted, 143 unsigned long clk, int max) 144 { 145 int result; 146 147 result = DIV_ROUND_UP((wanted * clk), NSEC_PER_MSEC) - 1; 148 149 dev_dbg(&pdev->dev, "%s: result %d from %ld, %d\n", __func__, result, 150 clk, wanted); 151 152 /* It is generally OK to have a more relaxed timing than requested... */ 153 if (result < 0) 154 result = 0; 155 156 /* ... But configuring tighter timings is not an option. */ 157 else if (result > max) 158 result = -EINVAL; 159 160 return result; 161 } 162 163 /** 164 * aemif_config_abus - configure async bus parameters 165 * @pdev: platform device to configure for 166 * @csnum: aemif chip select number 167 * 168 * This function programs the given timing values (in real clock) into the 169 * AEMIF registers taking the AEMIF clock into account. 170 * 171 * This function does not use any locking while programming the AEMIF 172 * because it is expected that there is only one user of a given 173 * chip-select. 174 * 175 * Returns 0 on success, else negative errno. 176 */ 177 static int aemif_config_abus(struct platform_device *pdev, int csnum) 178 { 179 struct aemif_device *aemif = platform_get_drvdata(pdev); 180 struct aemif_cs_data *data = &aemif->cs_data[csnum]; 181 int ta, rhold, rstrobe, rsetup, whold, wstrobe, wsetup; 182 unsigned long clk_rate = aemif->clk_rate; 183 unsigned offset; 184 u32 set, val; 185 186 offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4; 187 188 ta = aemif_calc_rate(pdev, data->ta, clk_rate, TA_MAX); 189 rhold = aemif_calc_rate(pdev, data->rhold, clk_rate, RHOLD_MAX); 190 rstrobe = aemif_calc_rate(pdev, data->rstrobe, clk_rate, RSTROBE_MAX); 191 rsetup = aemif_calc_rate(pdev, data->rsetup, clk_rate, RSETUP_MAX); 192 whold = aemif_calc_rate(pdev, data->whold, clk_rate, WHOLD_MAX); 193 wstrobe = aemif_calc_rate(pdev, data->wstrobe, clk_rate, WSTROBE_MAX); 194 wsetup = aemif_calc_rate(pdev, data->wsetup, clk_rate, WSETUP_MAX); 195 196 if (ta < 0 || rhold < 0 || rstrobe < 0 || rsetup < 0 || 197 whold < 0 || wstrobe < 0 || wsetup < 0) { 198 dev_err(&pdev->dev, "%s: cannot get suitable timings\n", 199 __func__); 200 return -EINVAL; 201 } 202 203 set = TA(ta) | RHOLD(rhold) | RSTROBE(rstrobe) | RSETUP(rsetup) | 204 WHOLD(whold) | WSTROBE(wstrobe) | WSETUP(wsetup); 205 206 set |= (data->asize & ACR_ASIZE_MASK); 207 if (data->enable_ew) 208 set |= ACR_EW_MASK; 209 if (data->enable_ss) 210 set |= ACR_SS_MASK; 211 212 val = readl(aemif->base + offset); 213 val &= ~CONFIG_MASK; 214 val |= set; 215 writel(val, aemif->base + offset); 216 217 return 0; 218 } 219 220 static inline int aemif_cycles_to_nsec(int val, unsigned long clk_rate) 221 { 222 return ((val + 1) * NSEC_PER_MSEC) / clk_rate; 223 } 224 225 /** 226 * aemif_get_hw_params - function to read hw register values 227 * @pdev: platform device to read for 228 * @csnum: aemif chip select number 229 * 230 * This function reads the defaults from the registers and update 231 * the timing values. Required for get/set commands and also for 232 * the case when driver needs to use defaults in hardware. 233 */ 234 static void aemif_get_hw_params(struct platform_device *pdev, int csnum) 235 { 236 struct aemif_device *aemif = platform_get_drvdata(pdev); 237 struct aemif_cs_data *data = &aemif->cs_data[csnum]; 238 unsigned long clk_rate = aemif->clk_rate; 239 u32 val, offset; 240 241 offset = A1CR_OFFSET + (data->cs - aemif->cs_offset) * 4; 242 val = readl(aemif->base + offset); 243 244 data->ta = aemif_cycles_to_nsec(TA_VAL(val), clk_rate); 245 data->rhold = aemif_cycles_to_nsec(RHOLD_VAL(val), clk_rate); 246 data->rstrobe = aemif_cycles_to_nsec(RSTROBE_VAL(val), clk_rate); 247 data->rsetup = aemif_cycles_to_nsec(RSETUP_VAL(val), clk_rate); 248 data->whold = aemif_cycles_to_nsec(WHOLD_VAL(val), clk_rate); 249 data->wstrobe = aemif_cycles_to_nsec(WSTROBE_VAL(val), clk_rate); 250 data->wsetup = aemif_cycles_to_nsec(WSETUP_VAL(val), clk_rate); 251 data->enable_ew = EW_VAL(val); 252 data->enable_ss = SS_VAL(val); 253 data->asize = val & ASIZE_MAX; 254 } 255 256 /** 257 * of_aemif_parse_abus_config - parse CS configuration from DT 258 * @pdev: platform device to parse for 259 * @np: device node ptr 260 * 261 * This function update the emif async bus configuration based on the values 262 * configured in a cs device binding node. 263 */ 264 static int of_aemif_parse_abus_config(struct platform_device *pdev, 265 struct device_node *np) 266 { 267 struct aemif_device *aemif = platform_get_drvdata(pdev); 268 struct aemif_cs_data *data; 269 u32 cs; 270 u32 val; 271 272 if (of_property_read_u32(np, "ti,cs-chipselect", &cs)) { 273 dev_dbg(&pdev->dev, "cs property is required"); 274 return -EINVAL; 275 } 276 277 if (cs - aemif->cs_offset >= NUM_CS || cs < aemif->cs_offset) { 278 dev_dbg(&pdev->dev, "cs number is incorrect %d", cs); 279 return -EINVAL; 280 } 281 282 if (aemif->num_cs >= NUM_CS) { 283 dev_dbg(&pdev->dev, "cs count is more than %d", NUM_CS); 284 return -EINVAL; 285 } 286 287 data = &aemif->cs_data[aemif->num_cs]; 288 data->cs = cs; 289 290 /* read the current value in the hw register */ 291 aemif_get_hw_params(pdev, aemif->num_cs++); 292 293 /* override the values from device node */ 294 if (!of_property_read_u32(np, "ti,cs-min-turnaround-ns", &val)) 295 data->ta = val; 296 297 if (!of_property_read_u32(np, "ti,cs-read-hold-ns", &val)) 298 data->rhold = val; 299 300 if (!of_property_read_u32(np, "ti,cs-read-strobe-ns", &val)) 301 data->rstrobe = val; 302 303 if (!of_property_read_u32(np, "ti,cs-read-setup-ns", &val)) 304 data->rsetup = val; 305 306 if (!of_property_read_u32(np, "ti,cs-write-hold-ns", &val)) 307 data->whold = val; 308 309 if (!of_property_read_u32(np, "ti,cs-write-strobe-ns", &val)) 310 data->wstrobe = val; 311 312 if (!of_property_read_u32(np, "ti,cs-write-setup-ns", &val)) 313 data->wsetup = val; 314 315 if (!of_property_read_u32(np, "ti,cs-bus-width", &val)) 316 if (val == 16) 317 data->asize = 1; 318 data->enable_ew = of_property_read_bool(np, "ti,cs-extended-wait-mode"); 319 data->enable_ss = of_property_read_bool(np, "ti,cs-select-strobe-mode"); 320 return 0; 321 } 322 323 static const struct of_device_id aemif_of_match[] = { 324 { .compatible = "ti,davinci-aemif", }, 325 { .compatible = "ti,da850-aemif", }, 326 {}, 327 }; 328 MODULE_DEVICE_TABLE(of, aemif_of_match); 329 330 static int aemif_probe(struct platform_device *pdev) 331 { 332 int i; 333 int ret = -ENODEV; 334 struct resource *res; 335 struct device *dev = &pdev->dev; 336 struct device_node *np = dev->of_node; 337 struct device_node *child_np; 338 struct aemif_device *aemif; 339 struct aemif_platform_data *pdata; 340 struct of_dev_auxdata *dev_lookup; 341 342 if (np == NULL) 343 return 0; 344 345 aemif = devm_kzalloc(dev, sizeof(*aemif), GFP_KERNEL); 346 if (!aemif) 347 return -ENOMEM; 348 349 pdata = dev_get_platdata(&pdev->dev); 350 dev_lookup = pdata ? pdata->dev_lookup : NULL; 351 352 platform_set_drvdata(pdev, aemif); 353 354 aemif->clk = devm_clk_get(dev, NULL); 355 if (IS_ERR(aemif->clk)) { 356 dev_err(dev, "cannot get clock 'aemif'\n"); 357 return PTR_ERR(aemif->clk); 358 } 359 360 ret = clk_prepare_enable(aemif->clk); 361 if (ret) 362 return ret; 363 364 aemif->clk_rate = clk_get_rate(aemif->clk) / MSEC_PER_SEC; 365 366 if (of_device_is_compatible(np, "ti,da850-aemif")) 367 aemif->cs_offset = 2; 368 369 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 370 aemif->base = devm_ioremap_resource(dev, res); 371 if (IS_ERR(aemif->base)) { 372 ret = PTR_ERR(aemif->base); 373 goto error; 374 } 375 376 /* 377 * For every controller device node, there is a cs device node that 378 * describe the bus configuration parameters. This functions iterate 379 * over these nodes and update the cs data array. 380 */ 381 for_each_available_child_of_node(np, child_np) { 382 ret = of_aemif_parse_abus_config(pdev, child_np); 383 if (ret < 0) 384 goto error; 385 } 386 387 for (i = 0; i < aemif->num_cs; i++) { 388 ret = aemif_config_abus(pdev, i); 389 if (ret < 0) { 390 dev_err(dev, "Error configuring chip select %d\n", 391 aemif->cs_data[i].cs); 392 goto error; 393 } 394 } 395 396 /* 397 * Create a child devices explicitly from here to 398 * guarantee that the child will be probed after the AEMIF timing 399 * parameters are set. 400 */ 401 for_each_available_child_of_node(np, child_np) { 402 ret = of_platform_populate(child_np, NULL, dev_lookup, dev); 403 if (ret < 0) 404 goto error; 405 } 406 407 return 0; 408 error: 409 clk_disable_unprepare(aemif->clk); 410 return ret; 411 } 412 413 static int aemif_remove(struct platform_device *pdev) 414 { 415 struct aemif_device *aemif = platform_get_drvdata(pdev); 416 417 clk_disable_unprepare(aemif->clk); 418 return 0; 419 } 420 421 static struct platform_driver aemif_driver = { 422 .probe = aemif_probe, 423 .remove = aemif_remove, 424 .driver = { 425 .name = KBUILD_MODNAME, 426 .of_match_table = of_match_ptr(aemif_of_match), 427 }, 428 }; 429 430 module_platform_driver(aemif_driver); 431 432 MODULE_AUTHOR("Murali Karicheri <m-karicheri2@ti.com>"); 433 MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>"); 434 MODULE_DESCRIPTION("Texas Instruments AEMIF driver"); 435 MODULE_LICENSE("GPL v2"); 436 MODULE_ALIAS("platform:" KBUILD_MODNAME); 437