diff options
author | Bartosz Golaszewski <bgolaszewski@baylibre.com> | 2016-10-31 15:45:34 +0100 |
---|---|---|
committer | Sekhar Nori <nsekhar@ti.com> | 2016-11-14 17:18:34 +0530 |
commit | 62a8a73923edf97cdc4997a99065045743caddf1 (patch) | |
tree | 02a328bf6067eaa11326784f3e04fb0e3dbafab3 /drivers/memory/da8xx-ddrctl.c | |
parent | 1001354ca34179f3db924eb66672442a173147dc (diff) | |
download | linux-next-62a8a73923edf97cdc4997a99065045743caddf1.tar.gz |
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.c | 175 |
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"); |