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Release 4.14 drivers/memory/da8xx-ddrctl.c

Directory: drivers/memory
/*
 * 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/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; }

Contributors

PersonTokensPropCommitsCommitProp
Bartosz Golaszewski71100.00%1100.00%
Total71100.00%1100.00%


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; }

Contributors

PersonTokensPropCommitsCommitProp
Bartosz Golaszewski63100.00%1100.00%
Total63100.00%1100.00%


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 defined for this board\n"); 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; }

Contributors

PersonTokensPropCommitsCommitProp
Bartosz Golaszewski246100.00%2100.00%
Total246100.00%2100.00%

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");

Overall Contributors

PersonTokensPropCommitsCommitProp
Bartosz Golaszewski585100.00%2100.00%
Total585100.00%2100.00%
Directory: drivers/memory
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