drivers/memory/jz4780-nemc.c

   1 /*
   2  * JZ4780 NAND/external memory controller (NEMC)
   3  *
   4  * Copyright (c) 2015 Imagination Technologies
   5  * Author: Alex Smith <alex@alex-smith.me.uk>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms of the GNU General Public License version 2 as published
   9  * by the Free Software Foundation.
  10  */
  11
  12 #include <linux/clk.h>
  13 #include <linux/init.h>
  14 #include <linux/math64.h>
  15 #include <linux/of.h>
  16 #include <linux/of_address.h>
  17 #include <linux/of_device.h>
  18 #include <linux/of_platform.h>
  19 #include <linux/platform_device.h>
  20 #include <linux/slab.h>
  21 #include <linux/spinlock.h>
  22
  23 #include <linux/jz4780-nemc.h>
  24
  25 #define NEMC_SMCRn(n)           (0x14 + (((n) - 1) * 4))
  26 #define NEMC_NFCSR              0x50
  27
  28 #define NEMC_SMCR_SMT           BIT(0)
  29 #define NEMC_SMCR_BW_SHIFT      6
  30 #define NEMC_SMCR_BW_MASK       (0x3 << NEMC_SMCR_BW_SHIFT)
  31 #define NEMC_SMCR_BW_8          (0 << 6)
  32 #define NEMC_SMCR_TAS_SHIFT     8
  33 #define NEMC_SMCR_TAS_MASK      (0xf << NEMC_SMCR_TAS_SHIFT)
  34 #define NEMC_SMCR_TAH_SHIFT     12
  35 #define NEMC_SMCR_TAH_MASK      (0xf << NEMC_SMCR_TAH_SHIFT)
  36 #define NEMC_SMCR_TBP_SHIFT     16
  37 #define NEMC_SMCR_TBP_MASK      (0xf << NEMC_SMCR_TBP_SHIFT)
  38 #define NEMC_SMCR_TAW_SHIFT     20
  39 #define NEMC_SMCR_TAW_MASK      (0xf << NEMC_SMCR_TAW_SHIFT)
  40 #define NEMC_SMCR_TSTRV_SHIFT   24
  41 #define NEMC_SMCR_TSTRV_MASK    (0x3f << NEMC_SMCR_TSTRV_SHIFT)
  42
  43 #define NEMC_NFCSR_NFEn(n)      BIT(((n) - 1) << 1)
  44 #define NEMC_NFCSR_NFCEn(n)     BIT((((n) - 1) << 1) + 1)
  45 #define NEMC_NFCSR_TNFEn(n)     BIT(16 + (n) - 1)
  46
  47 struct jz4780_nemc {
  48         spinlock_t lock;
  49         struct device *dev;
  50         void __iomem *base;
  51         struct clk *clk;
  52         uint32_t clk_period;
  53         unsigned long banks_present;
  54 };
  55
  56 /**
  57  * jz4780_nemc_num_banks() - count the number of banks referenced by a device
  58  * @dev: device to count banks for, must be a child of the NEMC.
  59  *
  60  * Return: The number of unique NEMC banks referred to by the specified NEMC
  61  * child device. Unique here means that a device that references the same bank
  62  * multiple times in the its "reg" property will only count once.
  63  */
  64 unsigned int jz4780_nemc_num_banks(struct device *dev)
  65 {
  66         const __be32 *prop;
  67         unsigned int bank, count = 0;
  68         unsigned long referenced = 0;
  69         int i = 0;
  70
  71         while ((prop = of_get_address(dev->of_node, i++, NULL, NULL))) {
  72                 bank = of_read_number(prop, 1);
  73                 if (!(referenced & BIT(bank))) {
  74                         referenced |= BIT(bank);
  75                         count++;
  76                 }
  77         }
  78
  79         return count;
  80 }
  81 EXPORT_SYMBOL(jz4780_nemc_num_banks);
  82
  83 /**
  84  * jz4780_nemc_set_type() - set the type of device connected to a bank
  85  * @dev: child device of the NEMC.
  86  * @bank: bank number to configure.
  87  * @type: type of device connected to the bank.
  88  */
  89 void jz4780_nemc_set_type(struct device *dev, unsigned int bank,
  90                           enum jz4780_nemc_bank_type type)
  91 {
  92         struct jz4780_nemc *nemc = dev_get_drvdata(dev->parent);
  93         uint32_t nfcsr;
  94
  95         nfcsr = readl(nemc->base + NEMC_NFCSR);
  96
  97         /* TODO: Support toggle NAND devices. */
  98         switch (type) {
  99         case JZ4780_NEMC_BANK_SRAM:
 100                 nfcsr &= ~(NEMC_NFCSR_TNFEn(bank) | NEMC_NFCSR_NFEn(bank));
 101                 break;
 102         case JZ4780_NEMC_BANK_NAND:
 103                 nfcsr &= ~NEMC_NFCSR_TNFEn(bank);
 104                 nfcsr |= NEMC_NFCSR_NFEn(bank);
 105                 break;
 106         }
 107
 108         writel(nfcsr, nemc->base + NEMC_NFCSR);
 109 }
 110 EXPORT_SYMBOL(jz4780_nemc_set_type);
 111
 112 /**
 113  * jz4780_nemc_assert() - (de-)assert a NAND device's chip enable pin
 114  * @dev: child device of the NEMC.
 115  * @bank: bank number of device.
 116  * @assert: whether the chip enable pin should be asserted.
 117  *
 118  * (De-)asserts the chip enable pin for the NAND device connected to the
 119  * specified bank.
 120  */
 121 void jz4780_nemc_assert(struct device *dev, unsigned int bank, bool assert)
 122 {
 123         struct jz4780_nemc *nemc = dev_get_drvdata(dev->parent);
 124         uint32_t nfcsr;
 125
 126         nfcsr = readl(nemc->base + NEMC_NFCSR);
 127
 128         if (assert)
 129                 nfcsr |= NEMC_NFCSR_NFCEn(bank);
 130         else
 131                 nfcsr &= ~NEMC_NFCSR_NFCEn(bank);
 132
 133         writel(nfcsr, nemc->base + NEMC_NFCSR);
 134 }
 135 EXPORT_SYMBOL(jz4780_nemc_assert);
 136
 137 static uint32_t jz4780_nemc_clk_period(struct jz4780_nemc *nemc)
 138 {
 139         unsigned long rate;
 140
 141         rate = clk_get_rate(nemc->clk);
 142         if (!rate)
 143                 return 0;
 144
 145         /* Return in picoseconds. */
 146         return div64_ul(1000000000000ull, rate);
 147 }
 148
 149 static uint32_t jz4780_nemc_ns_to_cycles(struct jz4780_nemc *nemc, uint32_t ns)
 150 {
 151         return ((ns * 1000) + nemc->clk_period - 1) / nemc->clk_period;
 152 }
 153
 154 static bool jz4780_nemc_configure_bank(struct jz4780_nemc *nemc,
 155                                        unsigned int bank,
 156                                        struct device_node *node)
 157 {
 158         uint32_t smcr, val, cycles;
 159
 160         /*
 161          * Conversion of tBP and tAW cycle counts to values supported by the
 162          * hardware (round up to the next supported value).
 163          */
 164         static const uint32_t convert_tBP_tAW[] = {
 165                 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10,
 166
 167                 /* 11 - 12 -> 12 cycles */
 168                 11, 11,
 169
 170                 /* 13 - 15 -> 15 cycles */
 171                 12, 12, 12,
 172
 173                 /* 16 - 20 -> 20 cycles */
 174                 13, 13, 13, 13, 13,
 175
 176                 /* 21 - 25 -> 25 cycles */
 177                 14, 14, 14, 14, 14,
 178
 179                 /* 26 - 31 -> 31 cycles */
 180                 15, 15, 15, 15, 15, 15
 181         };
 182
 183         smcr = readl(nemc->base + NEMC_SMCRn(bank));
 184         smcr &= ~NEMC_SMCR_SMT;
 185
 186         if (!of_property_read_u32(node, "ingenic,nemc-bus-width", &val)) {
 187                 smcr &= ~NEMC_SMCR_BW_MASK;
 188                 switch (val) {
 189                 case 8:
 190                         smcr |= NEMC_SMCR_BW_8;
 191                         break;
 192                 default:
 193                         /*
 194                          * Earlier SoCs support a 16 bit bus width (the 4780
 195                          * does not), until those are properly supported, error.
 196                          */
 197                         dev_err(nemc->dev, "unsupported bus width: %u\n", val);
 198                         return false;
 199                 }
 200         }
 201
 202         if (of_property_read_u32(node, "ingenic,nemc-tAS", &val) == 0) {
 203                 smcr &= ~NEMC_SMCR_TAS_MASK;
 204                 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
 205                 if (cycles > 15) {
 206                         dev_err(nemc->dev, "tAS %u is too high (%u cycles)\n",
 207                                 val, cycles);
 208                         return false;
 209                 }
 210
 211                 smcr |= cycles << NEMC_SMCR_TAS_SHIFT;
 212         }
 213
 214         if (of_property_read_u32(node, "ingenic,nemc-tAH", &val) == 0) {
 215                 smcr &= ~NEMC_SMCR_TAH_MASK;
 216                 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
 217                 if (cycles > 15) {
 218                         dev_err(nemc->dev, "tAH %u is too high (%u cycles)\n",
 219                                 val, cycles);
 220                         return false;
 221                 }
 222
 223                 smcr |= cycles << NEMC_SMCR_TAH_SHIFT;
 224         }
 225
 226         if (of_property_read_u32(node, "ingenic,nemc-tBP", &val) == 0) {
 227                 smcr &= ~NEMC_SMCR_TBP_MASK;
 228                 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
 229                 if (cycles > 31) {
 230                         dev_err(nemc->dev, "tBP %u is too high (%u cycles)\n",
 231                                 val, cycles);
 232                         return false;
 233                 }
 234
 235                 smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TBP_SHIFT;
 236         }
 237
 238         if (of_property_read_u32(node, "ingenic,nemc-tAW", &val) == 0) {
 239                 smcr &= ~NEMC_SMCR_TAW_MASK;
 240                 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
 241                 if (cycles > 31) {
 242                         dev_err(nemc->dev, "tAW %u is too high (%u cycles)\n",
 243                                 val, cycles);
 244                         return false;
 245                 }
 246
 247                 smcr |= convert_tBP_tAW[cycles] << NEMC_SMCR_TAW_SHIFT;
 248         }
 249
 250         if (of_property_read_u32(node, "ingenic,nemc-tSTRV", &val) == 0) {
 251                 smcr &= ~NEMC_SMCR_TSTRV_MASK;
 252                 cycles = jz4780_nemc_ns_to_cycles(nemc, val);
 253                 if (cycles > 63) {
 254                         dev_err(nemc->dev, "tSTRV %u is too high (%u cycles)\n",
 255                                 val, cycles);
 256                         return false;
 257                 }
 258
 259                 smcr |= cycles << NEMC_SMCR_TSTRV_SHIFT;
 260         }
 261
 262         writel(smcr, nemc->base + NEMC_SMCRn(bank));
 263         return true;
 264 }
 265
 266 static int jz4780_nemc_probe(struct platform_device *pdev)
 267 {
 268         struct device *dev = &pdev->dev;
 269         struct jz4780_nemc *nemc;
 270         struct resource *res;
 271         struct device_node *child;
 272         const __be32 *prop;
 273         unsigned int bank;
 274         unsigned long referenced;
 275         int i, ret;
 276
 277         nemc = devm_kzalloc(dev, sizeof(*nemc), GFP_KERNEL);
 278         if (!nemc)
 279                 return -ENOMEM;
 280
 281         spin_lock_init(&nemc->lock);
 282         nemc->dev = dev;
 283
 284         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 285         nemc->base = devm_ioremap_resource(dev, res);
 286         if (IS_ERR(nemc->base)) {
 287                 dev_err(dev, "failed to get I/O memory\n");
 288                 return PTR_ERR(nemc->base);
 289         }
 290
 291         writel(0, nemc->base + NEMC_NFCSR);
 292
 293         nemc->clk = devm_clk_get(dev, NULL);
 294         if (IS_ERR(nemc->clk)) {
 295                 dev_err(dev, "failed to get clock\n");
 296                 return PTR_ERR(nemc->clk);
 297         }
 298
 299         ret = clk_prepare_enable(nemc->clk);
 300         if (ret) {
 301                 dev_err(dev, "failed to enable clock: %d\n", ret);
 302                 return ret;
 303         }
 304
 305         nemc->clk_period = jz4780_nemc_clk_period(nemc);
 306         if (!nemc->clk_period) {
 307                 dev_err(dev, "failed to calculate clock period\n");
 308                 clk_disable_unprepare(nemc->clk);
 309                 return -EINVAL;
 310         }
 311
 312         /*
 313          * Iterate over child devices, check that they do not conflict with
 314          * each other, and register child devices for them. If a child device
 315          * has invalid properties, it is ignored and no platform device is
 316          * registered for it.
 317          */
 318         for_each_child_of_node(nemc->dev->of_node, child) {
 319                 referenced = 0;
 320                 i = 0;
 321                 while ((prop = of_get_address(child, i++, NULL, NULL))) {
 322                         bank = of_read_number(prop, 1);
 323                         if (bank < 1 || bank >= JZ4780_NEMC_NUM_BANKS) {
 324                                 dev_err(nemc->dev,
 325                                         "%pOF requests invalid bank %u\n",
 326                                         child, bank);
 327
 328                                 /* Will continue the outer loop below. */
 329                                 referenced = 0;
 330                                 break;
 331                         }
 332
 333                         referenced |= BIT(bank);
 334                 }
 335
 336                 if (!referenced) {
 337                         dev_err(nemc->dev, "%pOF has no addresses\n",
 338                                 child);
 339                         continue;
 340                 } else if (nemc->banks_present & referenced) {
 341                         dev_err(nemc->dev, "%pOF conflicts with another node\n",
 342                                 child);
 343                         continue;
 344                 }
 345
 346                 /* Configure bank parameters. */
 347                 for_each_set_bit(bank, &referenced, JZ4780_NEMC_NUM_BANKS) {
 348                         if (!jz4780_nemc_configure_bank(nemc, bank, child)) {
 349                                 referenced = 0;
 350                                 break;
 351                         }
 352                 }
 353
 354                 if (referenced) {
 355                         if (of_platform_device_create(child, NULL, nemc->dev))
 356                                 nemc->banks_present |= referenced;
 357                 }
 358         }
 359
 360         platform_set_drvdata(pdev, nemc);
 361         dev_info(dev, "JZ4780 NEMC initialised\n");
 362         return 0;
 363 }
 364
 365 static int jz4780_nemc_remove(struct platform_device *pdev)
 366 {
 367         struct jz4780_nemc *nemc = platform_get_drvdata(pdev);
 368
 369         clk_disable_unprepare(nemc->clk);
 370         return 0;
 371 }
 372
 373 static const struct of_device_id jz4780_nemc_dt_match[] = {
 374         { .compatible = "ingenic,jz4780-nemc" },
 375         {},
 376 };
 377
 378 static struct platform_driver jz4780_nemc_driver = {
 379         .probe          = jz4780_nemc_probe,
 380         .remove         = jz4780_nemc_remove,
 381         .driver = {
 382                 .name   = "jz4780-nemc",
 383                 .of_match_table = of_match_ptr(jz4780_nemc_dt_match),
 384         },
 385 };
 386
 387 static int __init jz4780_nemc_init(void)
 388 {
 389         return platform_driver_register(&jz4780_nemc_driver);
 390 }
 391 subsys_initcall(jz4780_nemc_init);