summaryrefslogtreecommitdiff
path: root/drivers/memory/da8xx-ddrctl.c
diff options
context:
space:
mode:
authorBartosz Golaszewski <bgolaszewski@baylibre.com>2016-10-31 17:45:34 +0300
committerSekhar Nori <nsekhar@ti.com>2016-11-14 14:48:34 +0300
commit62a8a73923edf97cdc4997a99065045743caddf1 (patch)
tree02a328bf6067eaa11326784f3e04fb0e3dbafab3 /drivers/memory/da8xx-ddrctl.c
parent1001354ca34179f3db924eb66672442a173147dc (diff)
downloadlinux-62a8a73923edf97cdc4997a99065045743caddf1.tar.xz
memory: davinci: add support for da8xx DDR2/mDDR controller
Create a new driver for the da8xx DDR2/mDDR controller and implement support for writing to the Peripheral Bus Burst Priority Register. Reviewed-by: Kevin Hilman <khilman@baylibre.com> Acked-by: Rob Herring <robh@kernel.org> Signed-off-by: Bartosz Golaszewski <bgolaszewski@baylibre.com> [nsekhar@ti.com: subject line adjustment] Signed-off-by: Sekhar Nori <nsekhar@ti.com>
Diffstat (limited to 'drivers/memory/da8xx-ddrctl.c')
-rw-r--r--drivers/memory/da8xx-ddrctl.c175
1 files changed, 175 insertions, 0 deletions
diff --git a/drivers/memory/da8xx-ddrctl.c b/drivers/memory/da8xx-ddrctl.c
new file mode 100644
index 000000000000..a20e7bbbcbe0
--- /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@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 + sizeof(u32) > resource_size(res)) {
+ dev_warn(dev,
+ "register offset of '%s' exceeds mapped memory size\n",
+ knob->name);
+ continue;
+ }
+
+ reg = readl(ddrctl + knob->reg);
+ reg &= knob->mask;
+ reg |= setting->val << knob->shift;
+
+ dev_dbg(dev, "writing 0x%08x to %s\n", reg, setting->name);
+
+ 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@baylibre.com>");
+MODULE_DESCRIPTION("TI da8xx DDR2/mDDR controller driver");
+MODULE_LICENSE("GPL v2");