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168 lines
3.9 KiB
168 lines
3.9 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* TI da8xx DDR2/mDDR controller driver |
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* |
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* Copyright (C) 2016 BayLibre SAS |
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* |
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* Author: |
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* Bartosz Golaszewski <[email protected]> |
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*/ |
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#include <linux/module.h> |
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#include <linux/of.h> |
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#include <linux/of_device.h> |
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#include <linux/platform_device.h> |
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#include <linux/io.h> |
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/* |
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* REVISIT: Linux doesn't have a good framework for the kind of performance |
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* knobs this driver controls. We can't use device tree properties as it deals |
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* with hardware configuration rather than description. We also don't want to |
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* commit to maintaining some random sysfs attributes. |
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* |
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* For now we just hardcode the register values for the boards that need |
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* some changes (as is the case for the LCD controller on da850-lcdk - the |
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* first board we support here). When linux gets an appropriate framework, |
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* we'll easily convert the driver to it. |
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*/ |
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struct da8xx_ddrctl_config_knob { |
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const char *name; |
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u32 reg; |
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u32 mask; |
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u32 shift; |
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}; |
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static const struct da8xx_ddrctl_config_knob da8xx_ddrctl_knobs[] = { |
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{ |
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.name = "da850-pbbpr", |
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.reg = 0x20, |
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.mask = 0xffffff00, |
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.shift = 0, |
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}, |
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}; |
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struct da8xx_ddrctl_setting { |
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const char *name; |
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u32 val; |
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}; |
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struct da8xx_ddrctl_board_settings { |
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const char *board; |
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const struct da8xx_ddrctl_setting *settings; |
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}; |
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static const struct da8xx_ddrctl_setting da850_lcdk_ddrctl_settings[] = { |
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{ |
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.name = "da850-pbbpr", |
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.val = 0x20, |
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}, |
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{ } |
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}; |
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static const struct da8xx_ddrctl_board_settings da8xx_ddrctl_board_confs[] = { |
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{ |
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.board = "ti,da850-lcdk", |
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.settings = da850_lcdk_ddrctl_settings, |
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}, |
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}; |
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static const struct da8xx_ddrctl_config_knob * |
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da8xx_ddrctl_match_knob(const struct da8xx_ddrctl_setting *setting) |
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{ |
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const struct da8xx_ddrctl_config_knob *knob; |
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int i; |
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for (i = 0; i < ARRAY_SIZE(da8xx_ddrctl_knobs); i++) { |
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knob = &da8xx_ddrctl_knobs[i]; |
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if (strcmp(knob->name, setting->name) == 0) |
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return knob; |
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} |
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return NULL; |
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} |
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static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void) |
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{ |
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const struct da8xx_ddrctl_board_settings *board_settings; |
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int i; |
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for (i = 0; i < ARRAY_SIZE(da8xx_ddrctl_board_confs); i++) { |
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board_settings = &da8xx_ddrctl_board_confs[i]; |
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if (of_machine_is_compatible(board_settings->board)) |
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return board_settings->settings; |
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} |
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return NULL; |
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} |
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static int da8xx_ddrctl_probe(struct platform_device *pdev) |
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{ |
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const struct da8xx_ddrctl_config_knob *knob; |
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const struct da8xx_ddrctl_setting *setting; |
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struct resource *res; |
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void __iomem *ddrctl; |
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struct device *dev; |
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u32 reg; |
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dev = &pdev->dev; |
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setting = da8xx_ddrctl_get_board_settings(); |
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if (!setting) { |
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dev_err(dev, "no settings defined for this board\n"); |
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return -EINVAL; |
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} |
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res = platform_get_resource(pdev, IORESOURCE_MEM, 0); |
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ddrctl = devm_ioremap_resource(dev, res); |
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if (IS_ERR(ddrctl)) { |
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dev_err(dev, "unable to map memory controller registers\n"); |
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return PTR_ERR(ddrctl); |
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} |
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for (; setting->name; setting++) { |
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knob = da8xx_ddrctl_match_knob(setting); |
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if (!knob) { |
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dev_warn(dev, |
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"no such config option: %s\n", setting->name); |
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continue; |
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} |
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if (knob->reg + sizeof(u32) > resource_size(res)) { |
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dev_warn(dev, |
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"register offset of '%s' exceeds mapped memory size\n", |
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knob->name); |
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continue; |
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} |
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reg = readl(ddrctl + knob->reg); |
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reg &= knob->mask; |
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reg |= setting->val << knob->shift; |
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dev_dbg(dev, "writing 0x%08x to %s\n", reg, setting->name); |
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writel(reg, ddrctl + knob->reg); |
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} |
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return 0; |
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} |
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static const struct of_device_id da8xx_ddrctl_of_match[] = { |
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{ .compatible = "ti,da850-ddr-controller", }, |
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{ }, |
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}; |
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static struct platform_driver da8xx_ddrctl_driver = { |
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.probe = da8xx_ddrctl_probe, |
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.driver = { |
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.name = "da850-ddr-controller", |
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.of_match_table = da8xx_ddrctl_of_match, |
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}, |
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}; |
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module_platform_driver(da8xx_ddrctl_driver); |
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MODULE_AUTHOR("Bartosz Golaszewski <[email protected]>"); |
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MODULE_DESCRIPTION("TI da8xx DDR2/mDDR controller driver"); |
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MODULE_LICENSE("GPL v2");
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