[PATCH 1/2] ARM: memory: da8xx-ddrctl: new driver
Bartosz Golaszewski
bgolaszewski at baylibre.com
Wed Oct 26 10:35:54 PDT 2016
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 at baylibre.com>
---
.../memory-controllers/ti-da8xx-ddrctl.txt | 20 +++
drivers/memory/Kconfig | 8 +
drivers/memory/Makefile | 1 +
drivers/memory/da8xx-ddrctl.c | 175 +++++++++++++++++++++
4 files changed, 204 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..7e271dd
--- /dev/null
+++ b/Documentation/devicetree/bindings/memory-controllers/ti-da8xx-ddrctl.txt
@@ -0,0 +1,20 @@
+* Device tree bindings for Texas Instruments da8xx DDR2/mDDR memory controller
+
+The DDR2/mDDR memory controller present on Texas Instruments da8xx SoCs features
+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-ddr-controller" - for da850 SoC based boards
+- reg: a tuple containing the base address of the memory
+ controller and the size of the memory area to map
+
+Example for da850 shown below.
+
+ddrctl {
+ compatible = "ti,da850-ddr-controller";
+ reg = <0xB0000000 0x100>;
+};
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..900e131
--- /dev/null
+++ b/drivers/memory/da8xx-ddrctl.c
@@ -0,0 +1,175 @@
+/*
+ * TI da8xx DDR2/mDDR controller driver
+ *
+ * Copyright (C) 2016 BayLibre SAS
+ *
+ * Author:
+ * Bartosz Golaszewski <bgolaszewski at 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/of_device.h>
+#include <linux/of_fdt.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+
+/*
+ * REVISIT: Linux doesn't have a good framework for the kind of performance
+ * knobs this driver controls. We can't use device tree properties as it deals
+ * with hardware configuration rather than description. We also don't want to
+ * commit to maintaining some random sysfs attributes.
+ *
+ * For now we just hardcode the register values for the boards that need
+ * some changes (as is the case for the LCD controller on da850-lcdk - the
+ * first board we support here). When linux gets an appropriate framework,
+ * we'll easily convert the driver to it.
+ */
+
+struct da8xx_ddrctl_config_knob {
+ const char *name;
+ u32 reg;
+ u32 mask;
+ u32 shift;
+};
+
+static const struct da8xx_ddrctl_config_knob da8xx_ddrctl_knobs[] = {
+ {
+ .name = "da850-pbbpr",
+ .reg = 0x20,
+ .mask = 0xffffff00,
+ .shift = 0,
+ },
+};
+
+struct da8xx_ddrctl_setting {
+ const char *name;
+ u32 val;
+};
+
+struct da8xx_ddrctl_board_settings {
+ const char *board;
+ const struct da8xx_ddrctl_setting *settings;
+};
+
+static const struct da8xx_ddrctl_setting da850_lcdk_ddrctl_settings[] = {
+ {
+ .name = "da850-pbbpr",
+ .val = 0x20,
+ },
+ { }
+};
+
+static const struct da8xx_ddrctl_board_settings da8xx_ddrctl_board_confs[] = {
+ {
+ .board = "ti,da850-lcdk",
+ .settings = da850_lcdk_ddrctl_settings,
+ },
+};
+
+static const struct da8xx_ddrctl_config_knob *
+da8xx_ddrctl_match_knob(const struct da8xx_ddrctl_setting *setting)
+{
+ const struct da8xx_ddrctl_config_knob *knob;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(da8xx_ddrctl_knobs); i++) {
+ knob = &da8xx_ddrctl_knobs[i];
+
+ if (strcmp(knob->name, setting->name) == 0)
+ return knob;
+ }
+
+ return NULL;
+}
+
+static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void)
+{
+ const struct da8xx_ddrctl_board_settings *board_settings;
+ int i;
+
+ for (i = 0; i < ARRAY_SIZE(da8xx_ddrctl_board_confs); i++) {
+ board_settings = &da8xx_ddrctl_board_confs[i];
+
+ if (of_machine_is_compatible(board_settings->board))
+ return board_settings->settings;
+ }
+
+ return NULL;
+}
+
+static int da8xx_ddrctl_probe(struct platform_device *pdev)
+{
+ const struct da8xx_ddrctl_config_knob *knob;
+ const struct da8xx_ddrctl_setting *setting;
+ struct device_node *node;
+ struct resource *res;
+ void __iomem *ddrctl;
+ struct device *dev;
+ u32 reg;
+
+ dev = &pdev->dev;
+ node = dev->of_node;
+
+ setting = da8xx_ddrctl_get_board_settings();
+ if (!setting) {
+ dev_err(dev, "no settings for board '%s'\n",
+ of_flat_dt_get_machine_name());
+ return -EINVAL;
+ }
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ ddrctl = devm_ioremap_resource(dev, res);
+ if (IS_ERR(ddrctl)) {
+ dev_err(dev, "unable to map memory controller registers\n");
+ return PTR_ERR(ddrctl);
+ }
+
+ for (; setting->name; setting++) {
+ knob = da8xx_ddrctl_match_knob(setting);
+ if (!knob) {
+ dev_warn(dev,
+ "no such config option: %s\n", setting->name);
+ continue;
+ }
+
+ if (knob->reg > (res->end - res->start - sizeof(u32))) {
+ dev_warn(dev,
+ "register offset of '%s' exceeds mapped memory size\n",
+ knob->name);
+ continue;
+ }
+
+ reg = __raw_readl(ddrctl + knob->reg);
+ reg &= knob->mask;
+ reg |= setting->val << knob->shift;
+
+ dev_dbg(dev, "writing 0x%08x to %s\n", reg, setting->name);
+
+ __raw_writel(reg, ddrctl + knob->reg);
+ }
+
+ return 0;
+}
+
+static const struct of_device_id da8xx_ddrctl_of_match[] = {
+ { .compatible = "ti,da850-ddr-controller", },
+ { },
+};
+
+static struct platform_driver da8xx_ddrctl_driver = {
+ .probe = da8xx_ddrctl_probe,
+ .driver = {
+ .name = "da850-ddr-controller",
+ .of_match_table = da8xx_ddrctl_of_match,
+ },
+};
+module_platform_driver(da8xx_ddrctl_driver);
+
+MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski at baylibre.com>");
+MODULE_DESCRIPTION("TI da8xx DDR2/mDDR controller driver");
+MODULE_LICENSE("GPL v2");
--
2.9.3
More information about the linux-arm-kernel
mailing list