| /* |
| * DDR Self-Refresh Power Down (SRPD) support for Broadcom STB SoCs |
| * |
| * Copyright © 2014 Broadcom Corporation |
| * |
| * This program is free software; you can redistribute it and/or modify |
| * it under the terms of the GNU General Public License version 2 as |
| * published by the Free Software Foundation. |
| * |
| * This program is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| * GNU General Public License for more details. |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/platform_device.h> |
| #include <linux/of_device.h> |
| #include <linux/io.h> |
| |
| #define REG_SRPD_CONFIG 0x3c |
| #define INACT_COUNT_SHIFT 0 |
| #define INACT_COUNT_MASK 0xffff |
| #define SRPD_EN_SHIFT 16 |
| #define SRPD_EN_MASK 0x10000 |
| |
| #define REG_POWER_DOWN_STATUS 0x44 |
| #define SRPD_STATUS_SHIFT 1 |
| #define SRPD_STATUS_MASK 0x2 |
| |
| struct brcmstb_memc { |
| struct device *dev; |
| void __iomem *ddr_ctrl; |
| unsigned int timeout_cycles; |
| }; |
| |
| static int brcmstb_memc_srpd_config(struct brcmstb_memc *memc, |
| unsigned int cycles) |
| { |
| void __iomem *cfg = memc->ddr_ctrl + REG_SRPD_CONFIG; |
| 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 |= (1 << SRPD_EN_SHIFT); |
| |
| __raw_writel(val, cfg); |
| (void)__raw_readl(cfg); |
| |
| return 0; |
| } |
| |
| static ssize_t show_attr_srpd(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 store_attr_srpd(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; |
| |
| 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(srpd, S_IRUSR | S_IWUSR, show_attr_srpd, store_attr_srpd); |
| |
| static struct attribute *dev_attrs[] = { |
| &dev_attr_srpd.attr, |
| NULL, |
| }; |
| |
| static struct attribute_group dev_attr_group = { |
| .attrs = dev_attrs, |
| }; |
| |
| static int brcmstb_memc_probe(struct platform_device *pdev) |
| { |
| struct device *dev = &pdev->dev; |
| struct brcmstb_memc *memc; |
| struct resource *res; |
| int ret; |
| |
| memc = devm_kzalloc(dev, sizeof(*memc), GFP_KERNEL); |
| if (!memc) |
| return -ENOMEM; |
| |
| dev_set_drvdata(dev, memc); |
| |
| res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
| memc->ddr_ctrl = devm_ioremap_resource(dev, res); |
| if (IS_ERR(memc->ddr_ctrl)) |
| return PTR_ERR(memc->ddr_ctrl); |
| |
| ret = sysfs_create_group(&dev->kobj, &dev_attr_group); |
| if (ret) { |
| dev_err(dev, "failed to create attribute group (%d)\n", ret); |
| return ret; |
| } |
| |
| dev_info(dev, "registered\n"); |
| |
| 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; |
| } |
| |
| static const struct of_device_id brcmstb_memc_of_match[] = { |
| { .compatible = "brcm,brcmstb-memc-ddr" }, |
| {}, |
| }; |
| |
| static struct platform_driver brcmstb_memc_driver = { |
| .probe = brcmstb_memc_probe, |
| .remove = brcmstb_memc_remove, |
| .driver = { |
| .name = "brcmstb_memc", |
| .owner = THIS_MODULE, |
| .of_match_table = of_match_ptr(brcmstb_memc_of_match), |
| }, |
| }; |
| module_platform_driver(brcmstb_memc_driver); |
| |
| MODULE_LICENSE("GPL"); |
| MODULE_AUTHOR("Broadcom Corporation"); |
| MODULE_DESCRIPTION("DDR SRPD driver for Broadcom STB chips"); |