arch/arm/mach-tegra/tegra2_emc.c

   1 /*
   2  * Copyright (C) 2011 Google, Inc.
   3  *
   4  * Author:
   5  *      Colin Cross <ccross@android.com>
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  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
  18 #include <linux/kernel.h>
  19 #include <linux/device.h>
  20 #include <linux/clk.h>
  21 #include <linux/err.h>
  22 #include <linux/io.h>
  23 #include <linux/module.h>
  24 #include <linux/of.h>
  25 #include <linux/platform_device.h>
  26 #include <linux/platform_data/tegra_emc.h>
  27
  28 #include "tegra2_emc.h"
  29 #include "fuse.h"
  30
  31 #ifdef CONFIG_TEGRA_EMC_SCALING_ENABLE
  32 static bool emc_enable = true;
  33 #else
  34 static bool emc_enable;
  35 #endif
  36 module_param(emc_enable, bool, 0644);
  37
  38 static struct platform_device *emc_pdev;
  39 static void __iomem *emc_regbase;
  40
  41 static inline void emc_writel(u32 val, unsigned long addr)
  42 {
  43         writel(val, emc_regbase + addr);
  44 }
  45
  46 static inline u32 emc_readl(unsigned long addr)
  47 {
  48         return readl(emc_regbase + addr);
  49 }
  50
  51 static const unsigned long emc_reg_addr[TEGRA_EMC_NUM_REGS] = {
  52         0x2c,   /* RC */
  53         0x30,   /* RFC */
  54         0x34,   /* RAS */
  55         0x38,   /* RP */
  56         0x3c,   /* R2W */
  57         0x40,   /* W2R */
  58         0x44,   /* R2P */
  59         0x48,   /* W2P */
  60         0x4c,   /* RD_RCD */
  61         0x50,   /* WR_RCD */
  62         0x54,   /* RRD */
  63         0x58,   /* REXT */
  64         0x5c,   /* WDV */
  65         0x60,   /* QUSE */
  66         0x64,   /* QRST */
  67         0x68,   /* QSAFE */
  68         0x6c,   /* RDV */
  69         0x70,   /* REFRESH */
  70         0x74,   /* BURST_REFRESH_NUM */
  71         0x78,   /* PDEX2WR */
  72         0x7c,   /* PDEX2RD */
  73         0x80,   /* PCHG2PDEN */
  74         0x84,   /* ACT2PDEN */
  75         0x88,   /* AR2PDEN */
  76         0x8c,   /* RW2PDEN */
  77         0x90,   /* TXSR */
  78         0x94,   /* TCKE */
  79         0x98,   /* TFAW */
  80         0x9c,   /* TRPAB */
  81         0xa0,   /* TCLKSTABLE */
  82         0xa4,   /* TCLKSTOP */
  83         0xa8,   /* TREFBW */
  84         0xac,   /* QUSE_EXTRA */
  85         0x114,  /* FBIO_CFG6 */
  86         0xb0,   /* ODT_WRITE */
  87         0xb4,   /* ODT_READ */
  88         0x104,  /* FBIO_CFG5 */
  89         0x2bc,  /* CFG_DIG_DLL */
  90         0x2c0,  /* DLL_XFORM_DQS */
  91         0x2c4,  /* DLL_XFORM_QUSE */
  92         0x2e0,  /* ZCAL_REF_CNT */
  93         0x2e4,  /* ZCAL_WAIT_CNT */
  94         0x2a8,  /* AUTO_CAL_INTERVAL */
  95         0x2d0,  /* CFG_CLKTRIM_0 */
  96         0x2d4,  /* CFG_CLKTRIM_1 */
  97         0x2d8,  /* CFG_CLKTRIM_2 */
  98 };
  99
 100 /* Select the closest EMC rate that is higher than the requested rate */
 101 long tegra_emc_round_rate(unsigned long rate)
 102 {
 103         struct tegra_emc_pdata *pdata;
 104         int i;
 105         int best = -1;
 106         unsigned long distance = ULONG_MAX;
 107
 108         if (!emc_pdev)
 109                 return -EINVAL;
 110
 111         pdata = emc_pdev->dev.platform_data;
 112
 113         pr_debug("%s: %lu\n", __func__, rate);
 114
 115         /*
 116          * The EMC clock rate is twice the bus rate, and the bus rate is
 117          * measured in kHz
 118          */
 119         rate = rate / 2 / 1000;
 120
 121         for (i = 0; i < pdata->num_tables; i++) {
 122                 if (pdata->tables[i].rate >= rate &&
 123                     (pdata->tables[i].rate - rate) < distance) {
 124                         distance = pdata->tables[i].rate - rate;
 125                         best = i;
 126                 }
 127         }
 128
 129         if (best < 0)
 130                 return -EINVAL;
 131
 132         pr_debug("%s: using %lu\n", __func__, pdata->tables[best].rate);
 133
 134         return pdata->tables[best].rate * 2 * 1000;
 135 }
 136
 137 /*
 138  * The EMC registers have shadow registers.  When the EMC clock is updated
 139  * in the clock controller, the shadow registers are copied to the active
 140  * registers, allowing glitchless memory bus frequency changes.
 141  * This function updates the shadow registers for a new clock frequency,
 142  * and relies on the clock lock on the emc clock to avoid races between
 143  * multiple frequency changes
 144  */
 145 int tegra_emc_set_rate(unsigned long rate)
 146 {
 147         struct tegra_emc_pdata *pdata;
 148         int i;
 149         int j;
 150
 151         if (!emc_pdev)
 152                 return -EINVAL;
 153
 154         pdata = emc_pdev->dev.platform_data;
 155
 156         /*
 157          * The EMC clock rate is twice the bus rate, and the bus rate is
 158          * measured in kHz
 159          */
 160         rate = rate / 2 / 1000;
 161
 162         for (i = 0; i < pdata->num_tables; i++)
 163                 if (pdata->tables[i].rate == rate)
 164                         break;
 165
 166         if (i >= pdata->num_tables)
 167                 return -EINVAL;
 168
 169         pr_debug("%s: setting to %lu\n", __func__, rate);
 170
 171         for (j = 0; j < TEGRA_EMC_NUM_REGS; j++)
 172                 emc_writel(pdata->tables[i].regs[j], emc_reg_addr[j]);
 173
 174         emc_readl(pdata->tables[i].regs[TEGRA_EMC_NUM_REGS - 1]);
 175
 176         return 0;
 177 }
 178
 179 #ifdef CONFIG_OF
 180 static struct device_node *tegra_emc_ramcode_devnode(struct device_node *np)
 181 {
 182         struct device_node *iter;
 183         u32 reg;
 184
 185         for_each_child_of_node(np, iter) {
 186                 if (of_property_read_u32(iter, "nvidia,ram-code", &reg))
 187                         continue;
 188                 if (reg == tegra_bct_strapping)
 189                         return of_node_get(iter);
 190         }
 191
 192         return NULL;
 193 }
 194
 195 static struct tegra_emc_pdata *tegra_emc_dt_parse_pdata(
 196                 struct platform_device *pdev)
 197 {
 198         struct device_node *np = pdev->dev.of_node;
 199         struct device_node *tnp, *iter;
 200         struct tegra_emc_pdata *pdata;
 201         int ret, i, num_tables;
 202
 203         if (!np)
 204                 return NULL;
 205
 206         if (of_find_property(np, "nvidia,use-ram-code", NULL)) {
 207                 tnp = tegra_emc_ramcode_devnode(np);
 208                 if (!tnp)
 209                         dev_warn(&pdev->dev,
 210                                  "can't find emc table for ram-code 0x%02x\n",
 211                                  tegra_bct_strapping);
 212         } else
 213                 tnp = of_node_get(np);
 214
 215         if (!tnp)
 216                 return NULL;
 217
 218         num_tables = 0;
 219         for_each_child_of_node(tnp, iter)
 220                 if (of_device_is_compatible(iter, "nvidia,tegra20-emc-table"))
 221                         num_tables++;
 222
 223         if (!num_tables) {
 224                 pdata = NULL;
 225                 goto out;
 226         }
 227
 228         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 229         pdata->tables = devm_kzalloc(&pdev->dev,
 230                                      sizeof(*pdata->tables) * num_tables,
 231                                      GFP_KERNEL);
 232
 233         i = 0;
 234         for_each_child_of_node(tnp, iter) {
 235                 u32 prop;
 236
 237                 ret = of_property_read_u32(iter, "clock-frequency", &prop);
 238                 if (ret) {
 239                         dev_err(&pdev->dev, "no clock-frequency in %s\n",
 240                                 iter->full_name);
 241                         continue;
 242                 }
 243                 pdata->tables[i].rate = prop;
 244
 245                 ret = of_property_read_u32_array(iter, "nvidia,emc-registers",
 246                                                  pdata->tables[i].regs,
 247                                                  TEGRA_EMC_NUM_REGS);
 248                 if (ret) {
 249                         dev_err(&pdev->dev,
 250                                 "malformed emc-registers property in %s\n",
 251                                 iter->full_name);
 252                         continue;
 253                 }
 254
 255                 i++;
 256         }
 257         pdata->num_tables = i;
 258
 259 out:
 260         of_node_put(tnp);
 261         return pdata;
 262 }
 263 #else
 264 static struct tegra_emc_pdata *tegra_emc_dt_parse_pdata(
 265                 struct platform_device *pdev)
 266 {
 267         return NULL;
 268 }
 269 #endif
 270
 271 static struct tegra_emc_pdata *tegra_emc_fill_pdata(struct platform_device *pdev)
 272 {
 273         struct clk *c = clk_get_sys(NULL, "emc");
 274         struct tegra_emc_pdata *pdata;
 275         unsigned long khz;
 276         int i;
 277
 278         WARN_ON(pdev->dev.platform_data);
 279         BUG_ON(IS_ERR(c));
 280
 281         pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
 282         pdata->tables = devm_kzalloc(&pdev->dev, sizeof(*pdata->tables),
 283                                      GFP_KERNEL);
 284
 285         pdata->tables[0].rate = clk_get_rate(c) / 2 / 1000;
 286
 287         for (i = 0; i < TEGRA_EMC_NUM_REGS; i++)
 288                 pdata->tables[0].regs[i] = emc_readl(emc_reg_addr[i]);
 289
 290         pdata->num_tables = 1;
 291
 292         khz = pdata->tables[0].rate;
 293         dev_info(&pdev->dev, "no tables provided, using %ld kHz emc, "
 294                  "%ld kHz mem\n", khz * 2, khz);
 295
 296         return pdata;
 297 }
 298
 299 static int tegra_emc_probe(struct platform_device *pdev)
 300 {
 301         struct tegra_emc_pdata *pdata;
 302         struct resource *res;
 303
 304         if (!emc_enable) {
 305                 dev_err(&pdev->dev, "disabled per module parameter\n");
 306                 return -ENODEV;
 307         }
 308
 309         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 310         emc_regbase = devm_ioremap_resource(&pdev->dev, res);
 311         if (IS_ERR(emc_regbase))
 312                 return PTR_ERR(emc_regbase);
 313
 314         pdata = pdev->dev.platform_data;
 315
 316         if (!pdata)
 317                 pdata = tegra_emc_dt_parse_pdata(pdev);
 318
 319         if (!pdata)
 320                 pdata = tegra_emc_fill_pdata(pdev);
 321
 322         pdev->dev.platform_data = pdata;
 323
 324         emc_pdev = pdev;
 325
 326         return 0;
 327 }
 328
 329 static struct of_device_id tegra_emc_of_match[] = {
 330         { .compatible = "nvidia,tegra20-emc", },
 331         { },
 332 };
 333
 334 static struct platform_driver tegra_emc_driver = {
 335         .driver         = {
 336                 .name   = "tegra-emc",
 337                 .owner  = THIS_MODULE,
 338                 .of_match_table = tegra_emc_of_match,
 339         },
 340         .probe          = tegra_emc_probe,
 341 };
 342
 343 static int __init tegra_emc_init(void)
 344 {
 345         return platform_driver_register(&tegra_emc_driver);
 346 }
 347 device_initcall(tegra_emc_init);