LXR linux/drivers/memory/ti-aemif.c

   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 */
 100struct 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 */
 123struct 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 */
 142static 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 */
 177static 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
 220static 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 */
 234static 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 */
 264static 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
 323static const struct of_device_id aemif_of_match[] = {
 324        { .compatible = "ti,davinci-aemif", },
 325        { .compatible = "ti,da850-aemif", },
 326        {},
 327};
 328MODULE_DEVICE_TABLE(of, aemif_of_match);
 329
 330static 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;
 408error:
 409        clk_disable_unprepare(aemif->clk);
 410        return ret;
 411}
 412
 413static 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
 421static 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
 430module_platform_driver(aemif_driver);
 431
 432MODULE_AUTHOR("Murali Karicheri <m-karicheri2@ti.com>");
 433MODULE_AUTHOR("Ivan Khoronzhuk <ivan.khoronzhuk@ti.com>");
 434MODULE_DESCRIPTION("Texas Instruments AEMIF driver");
 435MODULE_LICENSE("GPL v2");
 436MODULE_ALIAS("platform:" KBUILD_MODNAME);
 437