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// 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.h>
#include <linux/platform_device.h>
#include <linux/property.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 int brcmstb_memc_probe(struct platform_device *pdev)
{
const struct brcmstb_memc_data *memc_data;
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);
memc_data = device_get_match_data(dev);
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 void brcmstb_memc_remove(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
sysfs_remove_group(&dev->kobj, &dev_attr_group);
}
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]
},
{}
};
MODULE_DEVICE_TABLE(of, brcmstb_memc_of_match);
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");
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