Create a new driver for the da8xx DDR2/mDDR controller and implement support for writing to the Peripheral Bus Burst Priority Register.
Signed-off-by: Bartosz Golaszewski bgolaszewski@baylibre.com --- .../memory-controllers/ti-da8xx-ddrctl.txt | 25 +++++++ drivers/memory/Kconfig | 8 +++ drivers/memory/Makefile | 1 + drivers/memory/da8xx-ddrctl.c | 77 ++++++++++++++++++++++ 4 files changed, 111 insertions(+) create mode 100644 Documentation/devicetree/bindings/memory-controllers/ti-da8xx-ddrctl.txt create mode 100644 drivers/memory/da8xx-ddrctl.c
diff --git a/Documentation/devicetree/bindings/memory-controllers/ti-da8xx-ddrctl.txt b/Documentation/devicetree/bindings/memory-controllers/ti-da8xx-ddrctl.txt new file mode 100644 index 0000000..e340404 --- /dev/null +++ b/Documentation/devicetree/bindings/memory-controllers/ti-da8xx-ddrctl.txt @@ -0,0 +1,25 @@ +* Device tree bindings for Texas Instruments da8xx DDR2/mDDR memory controller + +The DDR2/mDDR memory controller present on Texas Instruments da8xx SoCs memory +maps a set of registers which allow to tweak the controller's behavior. + +Documentation: +OMAP-L138 (DA850) - http://www.ti.com/lit/ug/spruh82c/spruh82c.pdf + +Required properties: + +- compatible: "ti,da850-ddrctl" + +Optional properties: + +- ti,pr-old-count: Priority raise old counter. Specifies the number of + memory transfers after which the DDR2/mDDR memory + controller will elevate the priority of the oldest + command in the command FIFO. Must be between 0-255. + +Example for da850 shown below. + +ddrctl { + compatible = "ti,da850-ddrctl"; + ti,pr-old-count = <0x20>; +}; diff --git a/drivers/memory/Kconfig b/drivers/memory/Kconfig index 4b4c0c3..ec80e35 100644 --- a/drivers/memory/Kconfig +++ b/drivers/memory/Kconfig @@ -134,6 +134,14 @@ config MTK_SMI mainly help enable/disable iommu and control the power domain and clocks for each local arbiter.
+config DA8XX_DDRCTL + bool "Texas Instruments da8xx DDR2/mDDR driver" + depends on ARCH_DAVINCI_DA8XX + help + This driver is for the DDR2/mDDR Memory Controller present on + Texas Instruments da8xx SoCs. It's used to tweak various memory + controller configuration options. + source "drivers/memory/samsung/Kconfig" source "drivers/memory/tegra/Kconfig"
diff --git a/drivers/memory/Makefile b/drivers/memory/Makefile index b20ae38..e88097fb 100644 --- a/drivers/memory/Makefile +++ b/drivers/memory/Makefile @@ -17,6 +17,7 @@ obj-$(CONFIG_MVEBU_DEVBUS) += mvebu-devbus.o obj-$(CONFIG_TEGRA20_MC) += tegra20-mc.o obj-$(CONFIG_JZ4780_NEMC) += jz4780-nemc.o obj-$(CONFIG_MTK_SMI) += mtk-smi.o +obj-$(CONFIG_DA8XX_DDRCTL) += da8xx-ddrctl.o
obj-$(CONFIG_SAMSUNG_MC) += samsung/ obj-$(CONFIG_TEGRA_MC) += tegra/ diff --git a/drivers/memory/da8xx-ddrctl.c b/drivers/memory/da8xx-ddrctl.c new file mode 100644 index 0000000..dcd0a61 --- /dev/null +++ b/drivers/memory/da8xx-ddrctl.c @@ -0,0 +1,77 @@ +/* + * TI da8xx DDR2/mDDR controller driver + * + * Copyright (C) 2016 BayLibre SAS + * + * Author: + * Bartosz Golaszewski bgolaszewski@baylibre.com + * + * 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. + */ + +#include <linux/module.h> +#include <linux/of.h> +#include <linux/platform_device.h> +#include <linux/io.h> + +#define DA8XX_DDR_CTL_BASE 0xB0000000 +#define DA8XX_PBBPR_OFFSET 0x00000020 +#define DA8XX_PBBPR_REG(p) ((p) + DA8XX_PBBPR_OFFSET) + +#define DA8XX_PBBPR_MAX 0xff + +static void da8xx_ddrctl_set_pbbpr(void __iomem *ddrctl, struct device *dev) +{ + struct device_node *node = dev->of_node; + u32 pr_old_count; + int ret; + + ret = of_property_read_u32(node, "ti,pr-old-count", &pr_old_count); + if (ret) + return; + + if (pr_old_count > DA8XX_PBBPR_MAX) { + dev_warn(dev, "priority raise old counter value too high\n"); + return; + } + + __raw_writel(pr_old_count, DA8XX_PBBPR_REG(ddrctl)); +} + +static int da8xx_ddrctl_probe(struct platform_device *pdev) +{ + struct device *dev = &pdev->dev; + void __iomem *ddrctl; + + ddrctl = ioremap(DA8XX_DDR_CTL_BASE, SZ_256); + if (!ddrctl) { + dev_err(dev, "unable to map memory controller registers\n"); + return -EIO; + } + + da8xx_ddrctl_set_pbbpr(ddrctl, dev); + + iounmap(ddrctl); + + return 0; +} + +static const struct of_device_id da8xx_ddrctl_of_match[] = { + { .compatible = "ti,da850-ddrctl", }, + { }, +}; + +static struct platform_driver da8xx_ddrctl_driver = { + .probe = da8xx_ddrctl_probe, + .driver = { + .name = "da8xx-ddrctl", + .of_match_table = da8xx_ddrctl_of_match, + }, +}; +module_platform_driver(da8xx_ddrctl_driver); + +MODULE_AUTHOR("Bartosz Golaszewski bgolaszewski@baylibre.com"); +MODULE_DESCRIPTION("TI da8xx DDR2/mDDR controller driver"); +MODULE_LICENSE("GPL v2");