On 22/07/2022 20:41, Florian Fainelli wrote:
> Add support for configuring the Self Refresh Power Down (SRPD)
> inactivity timeout on Broadcom STB chips. This is used to conserve power
> when the DRAM activity is reduced.
>
> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
> ---
> drivers/memory/Kconfig | 9 +
> drivers/memory/Makefile | 1 +
> drivers/memory/brcmstb_memc.c | 304 ++++++++++++++++++++++++++++++++++
> 3 files changed, 314 insertions(+)
> create mode 100644 drivers/memory/brcmstb_memc.c
>
> diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig
> index ac1a411648d8..fac290e48e0b 100644
> --- a/drivers/memory/Kconfig
> +++ b/drivers/memory/Kconfig
> @@ -66,6 +66,15 @@ config BRCMSTB_DPFE
> for the DRAM's temperature. Slower refresh rate means cooler RAM,
> higher refresh rate means hotter RAM.
>
> +config BRCMSTB_MEMC
> + tristate "Broadcom STB MEMC driver"
> + default ARCH_BRCMSTB
> + depends on ARCH_BRCMSTB || COMPILE_TEST
> + help
> + This driver provides a way to configure the Broadcom STB memory
> + controller and specifically control the Self Refresh Power Down
> + (SRPD) inactivity timeout.
> +
> config BT1_L2_CTL
> bool "Baikal-T1 CM2 L2-RAM Cache Control Block"
> depends on MIPS_BAIKAL_T1 || COMPILE_TEST
> diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile
> index bc7663ed1c25..e148f636c082 100644
> --- a/drivers/memory/Makefile
> +++ b/drivers/memory/Makefile
> @@ -11,6 +11,7 @@ obj-$(CONFIG_ARM_PL172_MPMC) += pl172.o
> obj-$(CONFIG_ATMEL_SDRAMC) += atmel-sdramc.o
> obj-$(CONFIG_ATMEL_EBI) += atmel-ebi.o
> obj-$(CONFIG_BRCMSTB_DPFE) += brcmstb_dpfe.o
> +obj-$(CONFIG_BRCMSTB_MEMC) += brcmstb_memc.o
> obj-$(CONFIG_BT1_L2_CTL) += bt1-l2-ctl.o
> obj-$(CONFIG_TI_AEMIF) += ti-aemif.o
> obj-$(CONFIG_TI_EMIF) += emif.o
> diff --git a/drivers/memory/brcmstb_memc.c b/drivers/memory/brcmstb_memc.c
> new file mode 100644
> index 000000000000..881da958c542
> --- /dev/null
> +++ b/drivers/memory/brcmstb_memc.c
> @@ -0,0 +1,304 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * DDR Self-Refresh Power Down (SRPD) support for Broadcom STB SoCs
> + *
> + */
> +
> +#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>
Let's order the includes by name. It reduces the chances of conflicts later.
> +
> +#define REG_MEMC_CNTRLR_CONFIG 0x00
> +#define CNTRLR_CONFIG_LPDDR4 5
This is also a SHIFT? Later you use such suffix.
> +#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;
> +}
> +
> +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 |= (1 << SRPD_EN_SHIFT);
BIT(SRPD_EN_SHIFT)
> +
> + writel_relaxed(val, cfg);
> + (void)readl_relaxed(cfg);
Leave a comment why do you need such read.
> +
> + 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)
You need to document the sysfs ABI.
> +{
> + struct brcmstb_memc *memc = dev_get_drvdata(dev);
> + unsigned int val;
> + int ret;
> +
Start with /*
> + /* Cannot change the inactivity timeout on LPDDR4 chips because the
...for this comment.
> + * 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;
> + struct resource *res;
> + 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);
> + if (!of_id || !of_id->data)
!of_id is not possible
!of_id->data is the same not possible (or even less...)
I would suggest to drop both or at least the latter.
> + return -EINVAL;
> +
> + memc_data = of_id->data;
> + memc->srpd_offset = memc_data->srpd_offset;
> +
> + res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + memc->ddr_ctrl = devm_ioremap_resource(dev, res);
devm_platform_ioremap_resource()
> + if (IS_ERR(memc->ddr_ctrl))
> + return PTR_ERR(memc->ddr_ctrl);
> +
> + of_property_read_u32(pdev->dev.of_node, "clock-frequency",
> + &memc->frequency);
Undocumented property.
> +
> + ret = sysfs_create_group(&dev->kobj, &dev_attr_group);
> + if (ret) {
> + dev_err(dev, "failed to create attribute group (%d)\n", ret);
I am pretty sure there was a helper to make it simpler, but canno recall
now...
> + 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 __maybe_unused 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 SPRD prior to suspending the system since that can
SRPD?
Comment starts with /* alone
> + * cause issues with e.g: XPT_DMA trying to hash memory
> + */
> + val = readl_relaxed(cfg);
> + val &= ~(1 << SRPD_EN_SHIFT);
~(BIT(SRPD_EN_SHIFT))
> + writel_relaxed(val, cfg);
> + (void)readl_relaxed(cfg);
> +
> + return 0;
> +}
> +
> +static int __maybe_unused 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 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",
> + .owner = THIS_MODULE,
> + .of_match_table = of_match_ptr(brcmstb_memc_of_match),
This does not match brcmstb_memc_of_match - you will have unused
variable warning. Drop of_match_ptr or add maybe_unused.
Best regards,
Krzysztof
