linux/drivers/memory/samsung/exynos-srom.c
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   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
  19static 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 */
  33struct 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 */
  44struct exynos_srom {
  45        struct device *dev;
  46        void __iomem *reg_base;
  47        struct exynos_srom_reg_dump *reg_offset;
  48};
  49
  50static struct exynos_srom_reg_dump *exynos_srom_alloc_reg_dump(
  51                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
  67static 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
 105static 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 %s\n",
 143                                child->name);
 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
 159static 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
 167static 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
 175static 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
 184static 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
 194static const struct of_device_id of_exynos_srom_ids[] = {
 195        {
 196                .compatible     = "samsung,exynos4210-srom",
 197        },
 198        {},
 199};
 200
 201static SIMPLE_DEV_PM_OPS(exynos_srom_pm_ops, exynos_srom_suspend, exynos_srom_resume);
 202
 203static 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};
 212builtin_platform_driver(exynos_srom_driver);
 213