1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * TI da8xx DDR2/mDDR controller driver 4 * 5 * Copyright (C) 2016 BayLibre SAS 6 * 7 * Author: 8 * Bartosz Golaszewski <bgolaszewski@baylibre.com> 9 */ 10 11 #include <linux/module.h> 12 #include <linux/of.h> 13 #include <linux/platform_device.h> 14 #include <linux/io.h> 15 16 /* 17 * REVISIT: Linux doesn't have a good framework for the kind of performance 18 * knobs this driver controls. We can't use device tree properties as it deals 19 * with hardware configuration rather than description. We also don't want to 20 * commit to maintaining some random sysfs attributes. 21 * 22 * For now we just hardcode the register values for the boards that need 23 * some changes (as is the case for the LCD controller on da850-lcdk - the 24 * first board we support here). When linux gets an appropriate framework, 25 * we'll easily convert the driver to it. 26 */ 27 28 struct da8xx_ddrctl_config_knob { 29 const char *name; 30 u32 reg; 31 u32 mask; 32 u32 shift; 33 }; 34 35 static const struct da8xx_ddrctl_config_knob da8xx_ddrctl_knobs[] = { 36 { 37 .name = "da850-pbbpr", 38 .reg = 0x20, 39 .mask = 0xffffff00, 40 .shift = 0, 41 }, 42 }; 43 44 struct da8xx_ddrctl_setting { 45 const char *name; 46 u32 val; 47 }; 48 49 struct da8xx_ddrctl_board_settings { 50 const char *board; 51 const struct da8xx_ddrctl_setting *settings; 52 }; 53 54 static const struct da8xx_ddrctl_setting da850_lcdk_ddrctl_settings[] = { 55 { 56 .name = "da850-pbbpr", 57 .val = 0x20, 58 }, 59 { } 60 }; 61 62 static const struct da8xx_ddrctl_board_settings da8xx_ddrctl_board_confs[] = { 63 { 64 .board = "ti,da850-lcdk", 65 .settings = da850_lcdk_ddrctl_settings, 66 }, 67 }; 68 69 static const struct da8xx_ddrctl_config_knob * 70 da8xx_ddrctl_match_knob(const struct da8xx_ddrctl_setting *setting) 71 { 72 const struct da8xx_ddrctl_config_knob *knob; 73 int i; 74 75 for (i = 0; i < ARRAY_SIZE(da8xx_ddrctl_knobs); i++) { 76 knob = &da8xx_ddrctl_knobs[i]; 77 78 if (strcmp(knob->name, setting->name) == 0) 79 return knob; 80 } 81 82 return NULL; 83 } 84 85 static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void) 86 { 87 const struct da8xx_ddrctl_board_settings *board_settings; 88 int i; 89 90 for (i = 0; i < ARRAY_SIZE(da8xx_ddrctl_board_confs); i++) { 91 board_settings = &da8xx_ddrctl_board_confs[i]; 92 93 if (of_machine_is_compatible(board_settings->board)) 94 return board_settings->settings; 95 } 96 97 return NULL; 98 } 99 100 static int da8xx_ddrctl_probe(struct platform_device *pdev) 101 { 102 const struct da8xx_ddrctl_config_knob *knob; 103 const struct da8xx_ddrctl_setting *setting; 104 struct resource *res; 105 void __iomem *ddrctl; 106 struct device *dev; 107 u32 reg; 108 109 dev = &pdev->dev; 110 111 setting = da8xx_ddrctl_get_board_settings(); 112 if (!setting) { 113 dev_err(dev, "no settings defined for this board\n"); 114 return -EINVAL; 115 } 116 117 ddrctl = devm_platform_get_and_ioremap_resource(pdev, 0, &res); 118 if (IS_ERR(ddrctl)) { 119 dev_err(dev, "unable to map memory controller registers\n"); 120 return PTR_ERR(ddrctl); 121 } 122 123 for (; setting->name; setting++) { 124 knob = da8xx_ddrctl_match_knob(setting); 125 if (!knob) { 126 dev_warn(dev, 127 "no such config option: %s\n", setting->name); 128 continue; 129 } 130 131 if (knob->reg + sizeof(u32) > resource_size(res)) { 132 dev_warn(dev, 133 "register offset of '%s' exceeds mapped memory size\n", 134 knob->name); 135 continue; 136 } 137 138 reg = readl(ddrctl + knob->reg); 139 reg &= knob->mask; 140 reg |= setting->val << knob->shift; 141 142 dev_dbg(dev, "writing 0x%08x to %s\n", reg, setting->name); 143 144 writel(reg, ddrctl + knob->reg); 145 } 146 147 return 0; 148 } 149 150 static const struct of_device_id da8xx_ddrctl_of_match[] = { 151 { .compatible = "ti,da850-ddr-controller", }, 152 { }, 153 }; 154 155 static struct platform_driver da8xx_ddrctl_driver = { 156 .probe = da8xx_ddrctl_probe, 157 .driver = { 158 .name = "da850-ddr-controller", 159 .of_match_table = da8xx_ddrctl_of_match, 160 }, 161 }; 162 module_platform_driver(da8xx_ddrctl_driver); 163 164 MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>"); 165 MODULE_DESCRIPTION("TI da8xx DDR2/mDDR controller driver"); 166