drivers/memory/brcmstb_memc.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * DDR Self-Refresh Power Down (SRPD) support for Broadcom STB SoCs
   4  *
   5  */
   6
   7 #include <linux/init.h>
   8 #include <linux/io.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/of.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/property.h>
  14
  15 #define REG_MEMC_CNTRLR_CONFIG          0x00
  16 #define  CNTRLR_CONFIG_LPDDR4_SHIFT     5
  17 #define  CNTRLR_CONFIG_MASK             0xf
  18 #define REG_MEMC_SRPD_CFG_21            0x20
  19 #define REG_MEMC_SRPD_CFG_20            0x34
  20 #define REG_MEMC_SRPD_CFG_1x            0x3c
  21 #define INACT_COUNT_SHIFT               0
  22 #define INACT_COUNT_MASK                0xffff
  23 #define SRPD_EN_SHIFT                   16
  24
  25 struct brcmstb_memc_data {
  26         u32 srpd_offset;
  27 };
  28
  29 struct brcmstb_memc {
  30         struct device *dev;
  31         void __iomem *ddr_ctrl;
  32         unsigned int timeout_cycles;
  33         u32 frequency;
  34         u32 srpd_offset;
  35 };
  36
  37 static int brcmstb_memc_uses_lpddr4(struct brcmstb_memc *memc)
  38 {
  39         void __iomem *config = memc->ddr_ctrl + REG_MEMC_CNTRLR_CONFIG;
  40         u32 reg;
  41
  42         reg = readl_relaxed(config) & CNTRLR_CONFIG_MASK;
  43
  44         return reg == CNTRLR_CONFIG_LPDDR4_SHIFT;
  45 }
  46
  47 static int brcmstb_memc_srpd_config(struct brcmstb_memc *memc,
  48                                     unsigned int cycles)
  49 {
  50         void __iomem *cfg = memc->ddr_ctrl + memc->srpd_offset;
  51         u32 val;
  52
  53         /* Max timeout supported in HW */
  54         if (cycles > INACT_COUNT_MASK)
  55                 return -EINVAL;
  56
  57         memc->timeout_cycles = cycles;
  58
  59         val = (cycles << INACT_COUNT_SHIFT) & INACT_COUNT_MASK;
  60         if (cycles)
  61                 val |= BIT(SRPD_EN_SHIFT);
  62
  63         writel_relaxed(val, cfg);
  64         /* Ensure the write is committed to the controller */
  65         (void)readl_relaxed(cfg);
  66
  67         return 0;
  68 }
  69
  70 static ssize_t frequency_show(struct device *dev,
  71                               struct device_attribute *attr, char *buf)
  72 {
  73         struct brcmstb_memc *memc = dev_get_drvdata(dev);
  74
  75         return sprintf(buf, "%d\n", memc->frequency);
  76 }
  77
  78 static ssize_t srpd_show(struct device *dev,
  79                          struct device_attribute *attr, char *buf)
  80 {
  81         struct brcmstb_memc *memc = dev_get_drvdata(dev);
  82
  83         return sprintf(buf, "%d\n", memc->timeout_cycles);
  84 }
  85
  86 static ssize_t srpd_store(struct device *dev, struct device_attribute *attr,
  87                           const char *buf, size_t count)
  88 {
  89         struct brcmstb_memc *memc = dev_get_drvdata(dev);
  90         unsigned int val;
  91         int ret;
  92
  93         /*
  94          * Cannot change the inactivity timeout on LPDDR4 chips because the
  95          * dynamic tuning process will also get affected by the inactivity
  96          * timeout, thus making it non functional.
  97          */
  98         if (brcmstb_memc_uses_lpddr4(memc))
  99                 return -EOPNOTSUPP;
 100
 101         ret = kstrtouint(buf, 10, &val);
 102         if (ret < 0)
 103                 return ret;
 104
 105         ret = brcmstb_memc_srpd_config(memc, val);
 106         if (ret)
 107                 return ret;
 108
 109         return count;
 110 }
 111
 112 static DEVICE_ATTR_RO(frequency);
 113 static DEVICE_ATTR_RW(srpd);
 114
 115 static struct attribute *dev_attrs[] = {
 116         &dev_attr_frequency.attr,
 117         &dev_attr_srpd.attr,
 118         NULL,
 119 };
 120
 121 static struct attribute_group dev_attr_group = {
 122         .attrs = dev_attrs,
 123 };
 124
 125 static int brcmstb_memc_probe(struct platform_device *pdev)
 126 {
 127         const struct brcmstb_memc_data *memc_data;
 128         struct device *dev = &pdev->dev;
 129         struct brcmstb_memc *memc;
 130         int ret;
 131
 132         memc = devm_kzalloc(dev, sizeof(*memc), GFP_KERNEL);
 133         if (!memc)
 134                 return -ENOMEM;
 135
 136         dev_set_drvdata(dev, memc);
 137
 138         memc_data = device_get_match_data(dev);
 139         memc->srpd_offset = memc_data->srpd_offset;
 140
 141         memc->ddr_ctrl = devm_platform_ioremap_resource(pdev, 0);
 142         if (IS_ERR(memc->ddr_ctrl))
 143                 return PTR_ERR(memc->ddr_ctrl);
 144
 145         of_property_read_u32(pdev->dev.of_node, "clock-frequency",
 146                              &memc->frequency);
 147
 148         ret = sysfs_create_group(&dev->kobj, &dev_attr_group);
 149         if (ret)
 150                 return ret;
 151
 152         return 0;
 153 }
 154
 155 static void brcmstb_memc_remove(struct platform_device *pdev)
 156 {
 157         struct device *dev = &pdev->dev;
 158
 159         sysfs_remove_group(&dev->kobj, &dev_attr_group);
 160 }
 161
 162 enum brcmstb_memc_hwtype {
 163         BRCMSTB_MEMC_V21,
 164         BRCMSTB_MEMC_V20,
 165         BRCMSTB_MEMC_V1X,
 166 };
 167
 168 static const struct brcmstb_memc_data brcmstb_memc_versions[] = {
 169         { .srpd_offset = REG_MEMC_SRPD_CFG_21 },
 170         { .srpd_offset = REG_MEMC_SRPD_CFG_20 },
 171         { .srpd_offset = REG_MEMC_SRPD_CFG_1x },
 172 };
 173
 174 static const struct of_device_id brcmstb_memc_of_match[] = {
 175         {
 176                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.1.x",
 177                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V1X]
 178         },
 179         {
 180                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.0",
 181                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V20]
 182         },
 183         {
 184                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.1",
 185                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 186         },
 187         {
 188                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.2",
 189                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 190         },
 191         {
 192                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.3",
 193                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 194         },
 195         {
 196                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.5",
 197                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 198         },
 199         {
 200                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.6",
 201                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 202         },
 203         {
 204                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.7",
 205                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 206         },
 207         {
 208                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.8",
 209                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 210         },
 211         {
 212                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.3.0",
 213                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 214         },
 215         {
 216                 .compatible = "brcm,brcmstb-memc-ddr-rev-b.3.1",
 217                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 218         },
 219         {
 220                 .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.0",
 221                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 222         },
 223         {
 224                 .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.1",
 225                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 226         },
 227         {
 228                 .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.2",
 229                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 230         },
 231         {
 232                 .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.3",
 233                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 234         },
 235         {
 236                 .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.4",
 237                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
 238         },
 239         /* default to the original offset */
 240         {
 241                 .compatible = "brcm,brcmstb-memc-ddr",
 242                 .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V1X]
 243         },
 244         {}
 245 };
 246
 247 static int brcmstb_memc_suspend(struct device *dev)
 248 {
 249         struct brcmstb_memc *memc = dev_get_drvdata(dev);
 250         void __iomem *cfg = memc->ddr_ctrl + memc->srpd_offset;
 251         u32 val;
 252
 253         if (memc->timeout_cycles == 0)
 254                 return 0;
 255
 256         /*
 257          * Disable SRPD prior to suspending the system since that can
 258          * cause issues with other memory clients managed by the ARM
 259          * trusted firmware to access memory.
 260          */
 261         val = readl_relaxed(cfg);
 262         val &= ~BIT(SRPD_EN_SHIFT);
 263         writel_relaxed(val, cfg);
 264         /* Ensure the write is committed to the controller */
 265         (void)readl_relaxed(cfg);
 266
 267         return 0;
 268 }
 269
 270 static int brcmstb_memc_resume(struct device *dev)
 271 {
 272         struct brcmstb_memc *memc = dev_get_drvdata(dev);
 273
 274         if (memc->timeout_cycles == 0)
 275                 return 0;
 276
 277         return brcmstb_memc_srpd_config(memc, memc->timeout_cycles);
 278 }
 279
 280 static DEFINE_SIMPLE_DEV_PM_OPS(brcmstb_memc_pm_ops, brcmstb_memc_suspend,
 281                                 brcmstb_memc_resume);
 282
 283 static struct platform_driver brcmstb_memc_driver = {
 284         .probe = brcmstb_memc_probe,
 285         .remove_new = brcmstb_memc_remove,
 286         .driver = {
 287                 .name           = "brcmstb_memc",
 288                 .of_match_table = brcmstb_memc_of_match,
 289                 .pm             = pm_ptr(&brcmstb_memc_pm_ops),
 290         },
 291 };
 292 module_platform_driver(brcmstb_memc_driver);
 293
 294 MODULE_LICENSE("GPL");
 295 MODULE_AUTHOR("Broadcom");
 296 MODULE_DESCRIPTION("DDR SRPD driver for Broadcom STB chips");