drivers/memory/samsung/exynos-srom.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 //
   3 // Copyright (c) 2015 Samsung Electronics Co., Ltd.
   4 //            http://www.samsung.com/
   5 //
   6 // Exynos - SROM Controller support
   7 // Author: Pankaj Dubey <pankaj.dubey@samsung.com>
   8
   9 #include <linux/io.h>
  10 #include <linux/init.h>
  11 #include <linux/of.h>
  12 #include <linux/of_address.h>
  13 #include <linux/of_platform.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/slab.h>
  16
  17 #include "exynos-srom.h"
  18
  19 static const unsigned long exynos_srom_offsets[] = {
  20         /* SROM side */
  21         EXYNOS_SROM_BW,
  22         EXYNOS_SROM_BC0,
  23         EXYNOS_SROM_BC1,
  24         EXYNOS_SROM_BC2,
  25         EXYNOS_SROM_BC3,
  26 };
  27
  28 /**
  29  * struct exynos_srom_reg_dump: register dump of SROM Controller registers.
  30  * @offset: srom register offset from the controller base address.
  31  * @value: the value of register under the offset.
  32  */
  33 struct exynos_srom_reg_dump {
  34         u32     offset;
  35         u32     value;
  36 };
  37
  38 /**
  39  * struct exynos_srom: platform data for exynos srom controller driver.
  40  * @dev: platform device pointer
  41  * @reg_base: srom base address
  42  * @reg_offset: exynos_srom_reg_dump pointer to hold offset and its value.
  43  */
  44 struct exynos_srom {
  45         struct device *dev;
  46         void __iomem *reg_base;
  47         struct exynos_srom_reg_dump *reg_offset;
  48 };
  49
  50 static struct exynos_srom_reg_dump *
  51 exynos_srom_alloc_reg_dump(const unsigned long *rdump,
  52                            unsigned long nr_rdump)
  53 {
  54         struct exynos_srom_reg_dump *rd;
  55         unsigned int i;
  56
  57         rd = kcalloc(nr_rdump, sizeof(*rd), GFP_KERNEL);
  58         if (!rd)
  59                 return NULL;
  60
  61         for (i = 0; i < nr_rdump; ++i)
  62                 rd[i].offset = rdump[i];
  63
  64         return rd;
  65 }
  66
  67 static int exynos_srom_configure_bank(struct exynos_srom *srom,
  68                                       struct device_node *np)
  69 {
  70         u32 bank, width, pmc = 0;
  71         u32 timing[6];
  72         u32 cs, bw;
  73
  74         if (of_property_read_u32(np, "reg", &bank))
  75                 return -EINVAL;
  76         if (of_property_read_u32(np, "reg-io-width", &width))
  77                 width = 1;
  78         if (of_property_read_bool(np, "samsung,srom-page-mode"))
  79                 pmc = 1 << EXYNOS_SROM_BCX__PMC__SHIFT;
  80         if (of_property_read_u32_array(np, "samsung,srom-timing", timing,
  81                                        ARRAY_SIZE(timing)))
  82                 return -EINVAL;
  83
  84         bank *= 4; /* Convert bank into shift/offset */
  85
  86         cs = 1 << EXYNOS_SROM_BW__BYTEENABLE__SHIFT;
  87         if (width == 2)
  88                 cs |= 1 << EXYNOS_SROM_BW__DATAWIDTH__SHIFT;
  89
  90         bw = readl_relaxed(srom->reg_base + EXYNOS_SROM_BW);
  91         bw = (bw & ~(EXYNOS_SROM_BW__CS_MASK << bank)) | (cs << bank);
  92         writel_relaxed(bw, srom->reg_base + EXYNOS_SROM_BW);
  93
  94         writel_relaxed(pmc | (timing[0] << EXYNOS_SROM_BCX__TACP__SHIFT) |
  95                        (timing[1] << EXYNOS_SROM_BCX__TCAH__SHIFT) |
  96                        (timing[2] << EXYNOS_SROM_BCX__TCOH__SHIFT) |
  97                        (timing[3] << EXYNOS_SROM_BCX__TACC__SHIFT) |
  98                        (timing[4] << EXYNOS_SROM_BCX__TCOS__SHIFT) |
  99                        (timing[5] << EXYNOS_SROM_BCX__TACS__SHIFT),
 100                        srom->reg_base + EXYNOS_SROM_BC0 + bank);
 101
 102         return 0;
 103 }
 104
 105 static int exynos_srom_probe(struct platform_device *pdev)
 106 {
 107         struct device_node *np, *child;
 108         struct exynos_srom *srom;
 109         struct device *dev = &pdev->dev;
 110         bool bad_bank_config = false;
 111
 112         np = dev->of_node;
 113         if (!np) {
 114                 dev_err(&pdev->dev, "could not find device info\n");
 115                 return -EINVAL;
 116         }
 117
 118         srom = devm_kzalloc(&pdev->dev,
 119                             sizeof(struct exynos_srom), GFP_KERNEL);
 120         if (!srom)
 121                 return -ENOMEM;
 122
 123         srom->dev = dev;
 124         srom->reg_base = of_iomap(np, 0);
 125         if (!srom->reg_base) {
 126                 dev_err(&pdev->dev, "iomap of exynos srom controller failed\n");
 127                 return -ENOMEM;
 128         }
 129
 130         platform_set_drvdata(pdev, srom);
 131
 132         srom->reg_offset = exynos_srom_alloc_reg_dump(exynos_srom_offsets,
 133                                                       ARRAY_SIZE(exynos_srom_offsets));
 134         if (!srom->reg_offset) {
 135                 iounmap(srom->reg_base);
 136                 return -ENOMEM;
 137         }
 138
 139         for_each_child_of_node(np, child) {
 140                 if (exynos_srom_configure_bank(srom, child)) {
 141                         dev_err(dev,
 142                                 "Could not decode bank configuration for %pOFn\n",
 143                                 child);
 144                         bad_bank_config = true;
 145                 }
 146         }
 147
 148         /*
 149          * If any bank failed to configure, we still provide suspend/resume,
 150          * but do not probe child devices
 151          */
 152         if (bad_bank_config)
 153                 return 0;
 154
 155         return of_platform_populate(np, NULL, NULL, dev);
 156 }
 157
 158 #ifdef CONFIG_PM_SLEEP
 159 static void exynos_srom_save(void __iomem *base,
 160                              struct exynos_srom_reg_dump *rd,
 161                              unsigned int num_regs)
 162 {
 163         for (; num_regs > 0; --num_regs, ++rd)
 164                 rd->value = readl(base + rd->offset);
 165 }
 166
 167 static void exynos_srom_restore(void __iomem *base,
 168                                 const struct exynos_srom_reg_dump *rd,
 169                                 unsigned int num_regs)
 170 {
 171         for (; num_regs > 0; --num_regs, ++rd)
 172                 writel(rd->value, base + rd->offset);
 173 }
 174
 175 static int exynos_srom_suspend(struct device *dev)
 176 {
 177         struct exynos_srom *srom = dev_get_drvdata(dev);
 178
 179         exynos_srom_save(srom->reg_base, srom->reg_offset,
 180                          ARRAY_SIZE(exynos_srom_offsets));
 181         return 0;
 182 }
 183
 184 static int exynos_srom_resume(struct device *dev)
 185 {
 186         struct exynos_srom *srom = dev_get_drvdata(dev);
 187
 188         exynos_srom_restore(srom->reg_base, srom->reg_offset,
 189                             ARRAY_SIZE(exynos_srom_offsets));
 190         return 0;
 191 }
 192 #endif
 193
 194 static const struct of_device_id of_exynos_srom_ids[] = {
 195         {
 196                 .compatible     = "samsung,exynos4210-srom",
 197         },
 198         {},
 199 };
 200
 201 static SIMPLE_DEV_PM_OPS(exynos_srom_pm_ops, exynos_srom_suspend, exynos_srom_resume);
 202
 203 static struct platform_driver exynos_srom_driver = {
 204         .probe = exynos_srom_probe,
 205         .driver = {
 206                 .name = "exynos-srom",
 207                 .of_match_table = of_exynos_srom_ids,
 208                 .pm = &exynos_srom_pm_ops,
 209                 .suppress_bind_attrs = true,
 210         },
 211 };
 212 builtin_platform_driver(exynos_srom_driver);