--- /dev/null
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * DDR Self-Refresh Power Down (SRPD) support for Broadcom STB SoCs
+ *
+ */
+
+#include <linux/init.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/of_device.h>
+#include <linux/platform_device.h>
+
+#define REG_MEMC_CNTRLR_CONFIG 0x00
+#define CNTRLR_CONFIG_LPDDR4_SHIFT 5
+#define CNTRLR_CONFIG_MASK 0xf
+#define REG_MEMC_SRPD_CFG_21 0x20
+#define REG_MEMC_SRPD_CFG_20 0x34
+#define REG_MEMC_SRPD_CFG_1x 0x3c
+#define INACT_COUNT_SHIFT 0
+#define INACT_COUNT_MASK 0xffff
+#define SRPD_EN_SHIFT 16
+
+struct brcmstb_memc_data {
+ u32 srpd_offset;
+};
+
+struct brcmstb_memc {
+ struct device *dev;
+ void __iomem *ddr_ctrl;
+ unsigned int timeout_cycles;
+ u32 frequency;
+ u32 srpd_offset;
+};
+
+static int brcmstb_memc_uses_lpddr4(struct brcmstb_memc *memc)
+{
+ void __iomem *config = memc->ddr_ctrl + REG_MEMC_CNTRLR_CONFIG;
+ u32 reg;
+
+ reg = readl_relaxed(config) & CNTRLR_CONFIG_MASK;
+
+ return reg == CNTRLR_CONFIG_LPDDR4_SHIFT;
+}
+
+static int brcmstb_memc_srpd_config(struct brcmstb_memc *memc,
+ unsigned int cycles)
+{
+ void __iomem *cfg = memc->ddr_ctrl + memc->srpd_offset;
+ u32 val;
+
+ /* Max timeout supported in HW */
+ if (cycles > INACT_COUNT_MASK)
+ return -EINVAL;
+
+ memc->timeout_cycles = cycles;
+
+ val = (cycles << INACT_COUNT_SHIFT) & INACT_COUNT_MASK;
+ if (cycles)
+ val |= BIT(SRPD_EN_SHIFT);
+
+ writel_relaxed(val, cfg);
+ /* Ensure the write is committed to the controller */
+ (void)readl_relaxed(cfg);
+
+ return 0;
+}
+
+static ssize_t frequency_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct brcmstb_memc *memc = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", memc->frequency);
+}
+
+static ssize_t srpd_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct brcmstb_memc *memc = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%d\n", memc->timeout_cycles);
+}
+
+static ssize_t srpd_store(struct device *dev, struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct brcmstb_memc *memc = dev_get_drvdata(dev);
+ unsigned int val;
+ int ret;
+
+ /*
+ * Cannot change the inactivity timeout on LPDDR4 chips because the
+ * dynamic tuning process will also get affected by the inactivity
+ * timeout, thus making it non functional.
+ */
+ if (brcmstb_memc_uses_lpddr4(memc))
+ return -EOPNOTSUPP;
+
+ ret = kstrtouint(buf, 10, &val);
+ if (ret < 0)
+ return ret;
+
+ ret = brcmstb_memc_srpd_config(memc, val);
+ if (ret)
+ return ret;
+
+ return count;
+}
+
+static DEVICE_ATTR_RO(frequency);
+static DEVICE_ATTR_RW(srpd);
+
+static struct attribute *dev_attrs[] = {
+ &dev_attr_frequency.attr,
+ &dev_attr_srpd.attr,
+ NULL,
+};
+
+static struct attribute_group dev_attr_group = {
+ .attrs = dev_attrs,
+};
+
+static const struct of_device_id brcmstb_memc_of_match[];
+
+static int brcmstb_memc_probe(struct platform_device *pdev)
+{
+ const struct brcmstb_memc_data *memc_data;
+ const struct of_device_id *of_id;
+ struct device *dev = &pdev->dev;
+ struct brcmstb_memc *memc;
+ int ret;
+
+ memc = devm_kzalloc(dev, sizeof(*memc), GFP_KERNEL);
+ if (!memc)
+ return -ENOMEM;
+
+ dev_set_drvdata(dev, memc);
+
+ of_id = of_match_device(brcmstb_memc_of_match, dev);
+ memc_data = of_id->data;
+ memc->srpd_offset = memc_data->srpd_offset;
+
+ memc->ddr_ctrl = devm_platform_ioremap_resource(pdev, 0);
+ if (IS_ERR(memc->ddr_ctrl))
+ return PTR_ERR(memc->ddr_ctrl);
+
+ of_property_read_u32(pdev->dev.of_node, "clock-frequency",
+ &memc->frequency);
+
+ ret = sysfs_create_group(&dev->kobj, &dev_attr_group);
+ if (ret)
+ return ret;
+
+ return 0;
+}
+
+static int brcmstb_memc_remove(struct platform_device *pdev)
+{
+ struct device *dev = &pdev->dev;
+
+ sysfs_remove_group(&dev->kobj, &dev_attr_group);
+
+ return 0;
+}
+
+enum brcmstb_memc_hwtype {
+ BRCMSTB_MEMC_V21,
+ BRCMSTB_MEMC_V20,
+ BRCMSTB_MEMC_V1X,
+};
+
+static const struct brcmstb_memc_data brcmstb_memc_versions[] = {
+ { .srpd_offset = REG_MEMC_SRPD_CFG_21 },
+ { .srpd_offset = REG_MEMC_SRPD_CFG_20 },
+ { .srpd_offset = REG_MEMC_SRPD_CFG_1x },
+};
+
+static const struct of_device_id brcmstb_memc_of_match[] = {
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.1.x",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V1X]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.0",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V20]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.1",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.2",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.3",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.5",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.6",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.7",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.2.8",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.3.0",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-b.3.1",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.0",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.1",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.2",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.3",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ {
+ .compatible = "brcm,brcmstb-memc-ddr-rev-c.1.4",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V21]
+ },
+ /* default to the original offset */
+ {
+ .compatible = "brcm,brcmstb-memc-ddr",
+ .data = &brcmstb_memc_versions[BRCMSTB_MEMC_V1X]
+ },
+ {}
+};
+
+static int brcmstb_memc_suspend(struct device *dev)
+{
+ struct brcmstb_memc *memc = dev_get_drvdata(dev);
+ void __iomem *cfg = memc->ddr_ctrl + memc->srpd_offset;
+ u32 val;
+
+ if (memc->timeout_cycles == 0)
+ return 0;
+
+ /*
+ * Disable SRPD prior to suspending the system since that can
+ * cause issues with other memory clients managed by the ARM
+ * trusted firmware to access memory.
+ */
+ val = readl_relaxed(cfg);
+ val &= ~BIT(SRPD_EN_SHIFT);
+ writel_relaxed(val, cfg);
+ /* Ensure the write is committed to the controller */
+ (void)readl_relaxed(cfg);
+
+ return 0;
+}
+
+static int brcmstb_memc_resume(struct device *dev)
+{
+ struct brcmstb_memc *memc = dev_get_drvdata(dev);
+
+ if (memc->timeout_cycles == 0)
+ return 0;
+
+ return brcmstb_memc_srpd_config(memc, memc->timeout_cycles);
+}
+
+static DEFINE_SIMPLE_DEV_PM_OPS(brcmstb_memc_pm_ops, brcmstb_memc_suspend,
+ brcmstb_memc_resume);
+
+static struct platform_driver brcmstb_memc_driver = {
+ .probe = brcmstb_memc_probe,
+ .remove = brcmstb_memc_remove,
+ .driver = {
+ .name = "brcmstb_memc",
+ .of_match_table = brcmstb_memc_of_match,
+ .pm = pm_ptr(&brcmstb_memc_pm_ops),
+ },
+};
+module_platform_driver(brcmstb_memc_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Broadcom");
+MODULE_DESCRIPTION("DDR SRPD driver for Broadcom STB chips");
projects / users / griffoul / linux.git / commitdiff