drivers/memory/samsung/exynos-srom.c

   1 /*
   2  * Copyright (c) 2015 Samsung Electronics Co., Ltd.
   3  *            http://www.samsung.com/
   4  *
   5  * EXYNOS - SROM Controller support
   6  * Author: Pankaj Dubey <pankaj.dubey@samsung.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/io.h>
  14 #include <linux/init.h>
  15 #include <linux/of.h>
  16 #include <linux/of_address.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/platform_device.h>
  19 #include <linux/slab.h>
  20
  21 #include "exynos-srom.h"
  22
  23 static const unsigned long exynos_srom_offsets[] = {
  24         /* SROM side */
  25         EXYNOS_SROM_BW,
  26         EXYNOS_SROM_BC0,
  27         EXYNOS_SROM_BC1,
  28         EXYNOS_SROM_BC2,
  29         EXYNOS_SROM_BC3,
  30 };
  31
  32 /**
  33  * struct exynos_srom_reg_dump: register dump of SROM Controller registers.
  34  * @offset: srom register offset from the controller base address.
  35  * @value: the value of register under the offset.
  36  */
  37 struct exynos_srom_reg_dump {
  38         u32     offset;
  39         u32     value;
  40 };
  41
  42 /**
  43  * struct exynos_srom: platform data for exynos srom controller driver.
  44  * @dev: platform device pointer
  45  * @reg_base: srom base address
  46  * @reg_offset: exynos_srom_reg_dump pointer to hold offset and its value.
  47  */
  48 struct exynos_srom {
  49         struct device *dev;
  50         void __iomem *reg_base;
  51         struct exynos_srom_reg_dump *reg_offset;
  52 };
  53
  54 static struct exynos_srom_reg_dump *exynos_srom_alloc_reg_dump(
  55                 const unsigned long *rdump,
  56                 unsigned long nr_rdump)
  57 {
  58         struct exynos_srom_reg_dump *rd;
  59         unsigned int i;
  60
  61         rd = kcalloc(nr_rdump, sizeof(*rd), GFP_KERNEL);
  62         if (!rd)
  63                 return NULL;
  64
  65         for (i = 0; i < nr_rdump; ++i)
  66                 rd[i].offset = rdump[i];
  67
  68         return rd;
  69 }
  70
  71 static int exynos_srom_configure_bank(struct exynos_srom *srom,
  72                                       struct device_node *np)
  73 {
  74         u32 bank, width, pmc = 0;
  75         u32 timing[6];
  76         u32 cs, bw;
  77
  78         if (of_property_read_u32(np, "reg", &bank))
  79                 return -EINVAL;
  80         if (of_property_read_u32(np, "reg-io-width", &width))
  81                 width = 1;
  82         if (of_property_read_bool(np, "samsung,srom-page-mode"))
  83                 pmc = 1 << EXYNOS_SROM_BCX__PMC__SHIFT;
  84         if (of_property_read_u32_array(np, "samsung,srom-timing", timing,
  85                                        ARRAY_SIZE(timing)))
  86                 return -EINVAL;
  87
  88         bank *= 4; /* Convert bank into shift/offset */
  89
  90         cs = 1 << EXYNOS_SROM_BW__BYTEENABLE__SHIFT;
  91         if (width == 2)
  92                 cs |= 1 << EXYNOS_SROM_BW__DATAWIDTH__SHIFT;
  93
  94         bw = readl_relaxed(srom->reg_base + EXYNOS_SROM_BW);
  95         bw = (bw & ~(EXYNOS_SROM_BW__CS_MASK << bank)) | (cs << bank);
  96         writel_relaxed(bw, srom->reg_base + EXYNOS_SROM_BW);
  97
  98         writel_relaxed(pmc | (timing[0] << EXYNOS_SROM_BCX__TACP__SHIFT) |
  99                        (timing[1] << EXYNOS_SROM_BCX__TCAH__SHIFT) |
 100                        (timing[2] << EXYNOS_SROM_BCX__TCOH__SHIFT) |
 101                        (timing[3] << EXYNOS_SROM_BCX__TACC__SHIFT) |
 102                        (timing[4] << EXYNOS_SROM_BCX__TCOS__SHIFT) |
 103                        (timing[5] << EXYNOS_SROM_BCX__TACS__SHIFT),
 104                        srom->reg_base + EXYNOS_SROM_BC0 + bank);
 105
 106         return 0;
 107 }
 108
 109 static int exynos_srom_probe(struct platform_device *pdev)
 110 {
 111         struct device_node *np, *child;
 112         struct exynos_srom *srom;
 113         struct device *dev = &pdev->dev;
 114         bool bad_bank_config = false;
 115
 116         np = dev->of_node;
 117         if (!np) {
 118                 dev_err(&pdev->dev, "could not find device info\n");
 119                 return -EINVAL;
 120         }
 121
 122         srom = devm_kzalloc(&pdev->dev,
 123                         sizeof(struct exynos_srom), GFP_KERNEL);
 124         if (!srom)
 125                 return -ENOMEM;
 126
 127         srom->dev = dev;
 128         srom->reg_base = of_iomap(np, 0);
 129         if (!srom->reg_base) {
 130                 dev_err(&pdev->dev, "iomap of exynos srom controller failed\n");
 131                 return -ENOMEM;
 132         }
 133
 134         platform_set_drvdata(pdev, srom);
 135
 136         srom->reg_offset = exynos_srom_alloc_reg_dump(exynos_srom_offsets,
 137                         ARRAY_SIZE(exynos_srom_offsets));
 138         if (!srom->reg_offset) {
 139                 iounmap(srom->reg_base);
 140                 return -ENOMEM;
 141         }
 142
 143         for_each_child_of_node(np, child) {
 144                 if (exynos_srom_configure_bank(srom, child)) {
 145                         dev_err(dev,
 146                                 "Could not decode bank configuration for %s\n",
 147                                 child->name);
 148                         bad_bank_config = true;
 149                 }
 150         }
 151
 152         /*
 153          * If any bank failed to configure, we still provide suspend/resume,
 154          * but do not probe child devices
 155          */
 156         if (bad_bank_config)
 157                 return 0;
 158
 159         return of_platform_populate(np, NULL, NULL, dev);
 160 }
 161
 162 #ifdef CONFIG_PM_SLEEP
 163 static void exynos_srom_save(void __iomem *base,
 164                                     struct exynos_srom_reg_dump *rd,
 165                                     unsigned int num_regs)
 166 {
 167         for (; num_regs > 0; --num_regs, ++rd)
 168                 rd->value = readl(base + rd->offset);
 169 }
 170
 171 static void exynos_srom_restore(void __iomem *base,
 172                                       const struct exynos_srom_reg_dump *rd,
 173                                       unsigned int num_regs)
 174 {
 175         for (; num_regs > 0; --num_regs, ++rd)
 176                 writel(rd->value, base + rd->offset);
 177 }
 178
 179 static int exynos_srom_suspend(struct device *dev)
 180 {
 181         struct exynos_srom *srom = dev_get_drvdata(dev);
 182
 183         exynos_srom_save(srom->reg_base, srom->reg_offset,
 184                                 ARRAY_SIZE(exynos_srom_offsets));
 185         return 0;
 186 }
 187
 188 static int exynos_srom_resume(struct device *dev)
 189 {
 190         struct exynos_srom *srom = dev_get_drvdata(dev);
 191
 192         exynos_srom_restore(srom->reg_base, srom->reg_offset,
 193                                 ARRAY_SIZE(exynos_srom_offsets));
 194         return 0;
 195 }
 196 #endif
 197
 198 static const struct of_device_id of_exynos_srom_ids[] = {
 199         {
 200                 .compatible     = "samsung,exynos4210-srom",
 201         },
 202         {},
 203 };
 204
 205 static SIMPLE_DEV_PM_OPS(exynos_srom_pm_ops, exynos_srom_suspend, exynos_srom_resume);
 206
 207 static struct platform_driver exynos_srom_driver = {
 208         .probe = exynos_srom_probe,
 209         .driver = {
 210                 .name = "exynos-srom",
 211                 .of_match_table = of_exynos_srom_ids,
 212                 .pm = &exynos_srom_pm_ops,
 213                 .suppress_bind_attrs = true,
 214         },
 215 };
 216 builtin_platform_driver(exynos_srom_driver);