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d2912cb1 | 1 | // SPDX-License-Identifier: GPL-2.0-only |
62a8a739 BG |
2 | /* |
3 | * TI da8xx DDR2/mDDR controller driver | |
4 | * | |
5 | * Copyright (C) 2016 BayLibre SAS | |
6 | * | |
7 | * Author: | |
8 | * Bartosz Golaszewski <bgolaszewski@baylibre.com> | |
62a8a739 BG |
9 | */ |
10 | ||
11 | #include <linux/module.h> | |
12 | #include <linux/of.h> | |
13 | #include <linux/of_device.h> | |
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14 | #include <linux/platform_device.h> |
15 | #include <linux/io.h> | |
16 | ||
17 | /* | |
18 | * REVISIT: Linux doesn't have a good framework for the kind of performance | |
19 | * knobs this driver controls. We can't use device tree properties as it deals | |
20 | * with hardware configuration rather than description. We also don't want to | |
21 | * commit to maintaining some random sysfs attributes. | |
22 | * | |
23 | * For now we just hardcode the register values for the boards that need | |
24 | * some changes (as is the case for the LCD controller on da850-lcdk - the | |
25 | * first board we support here). When linux gets an appropriate framework, | |
26 | * we'll easily convert the driver to it. | |
27 | */ | |
28 | ||
29 | struct da8xx_ddrctl_config_knob { | |
30 | const char *name; | |
31 | u32 reg; | |
32 | u32 mask; | |
33 | u32 shift; | |
34 | }; | |
35 | ||
36 | static const struct da8xx_ddrctl_config_knob da8xx_ddrctl_knobs[] = { | |
37 | { | |
38 | .name = "da850-pbbpr", | |
39 | .reg = 0x20, | |
40 | .mask = 0xffffff00, | |
41 | .shift = 0, | |
42 | }, | |
43 | }; | |
44 | ||
45 | struct da8xx_ddrctl_setting { | |
46 | const char *name; | |
47 | u32 val; | |
48 | }; | |
49 | ||
50 | struct da8xx_ddrctl_board_settings { | |
51 | const char *board; | |
52 | const struct da8xx_ddrctl_setting *settings; | |
53 | }; | |
54 | ||
55 | static const struct da8xx_ddrctl_setting da850_lcdk_ddrctl_settings[] = { | |
56 | { | |
57 | .name = "da850-pbbpr", | |
58 | .val = 0x20, | |
59 | }, | |
60 | { } | |
61 | }; | |
62 | ||
63 | static const struct da8xx_ddrctl_board_settings da8xx_ddrctl_board_confs[] = { | |
64 | { | |
65 | .board = "ti,da850-lcdk", | |
66 | .settings = da850_lcdk_ddrctl_settings, | |
67 | }, | |
68 | }; | |
69 | ||
70 | static const struct da8xx_ddrctl_config_knob * | |
71 | da8xx_ddrctl_match_knob(const struct da8xx_ddrctl_setting *setting) | |
72 | { | |
73 | const struct da8xx_ddrctl_config_knob *knob; | |
74 | int i; | |
75 | ||
76 | for (i = 0; i < ARRAY_SIZE(da8xx_ddrctl_knobs); i++) { | |
77 | knob = &da8xx_ddrctl_knobs[i]; | |
78 | ||
79 | if (strcmp(knob->name, setting->name) == 0) | |
80 | return knob; | |
81 | } | |
82 | ||
83 | return NULL; | |
84 | } | |
85 | ||
86 | static const struct da8xx_ddrctl_setting *da8xx_ddrctl_get_board_settings(void) | |
87 | { | |
88 | const struct da8xx_ddrctl_board_settings *board_settings; | |
89 | int i; | |
90 | ||
91 | for (i = 0; i < ARRAY_SIZE(da8xx_ddrctl_board_confs); i++) { | |
92 | board_settings = &da8xx_ddrctl_board_confs[i]; | |
93 | ||
94 | if (of_machine_is_compatible(board_settings->board)) | |
95 | return board_settings->settings; | |
96 | } | |
97 | ||
98 | return NULL; | |
99 | } | |
100 | ||
101 | static int da8xx_ddrctl_probe(struct platform_device *pdev) | |
102 | { | |
103 | const struct da8xx_ddrctl_config_knob *knob; | |
104 | const struct da8xx_ddrctl_setting *setting; | |
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105 | struct resource *res; |
106 | void __iomem *ddrctl; | |
107 | struct device *dev; | |
108 | u32 reg; | |
109 | ||
110 | dev = &pdev->dev; | |
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111 | |
112 | setting = da8xx_ddrctl_get_board_settings(); | |
113 | if (!setting) { | |
d0c7546f | 114 | dev_err(dev, "no settings defined for this board\n"); |
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115 | return -EINVAL; |
116 | } | |
117 | ||
933713f5 | 118 | ddrctl = devm_platform_get_and_ioremap_resource(pdev, 0, &res); |
62a8a739 BG |
119 | if (IS_ERR(ddrctl)) { |
120 | dev_err(dev, "unable to map memory controller registers\n"); | |
121 | return PTR_ERR(ddrctl); | |
122 | } | |
123 | ||
124 | for (; setting->name; setting++) { | |
125 | knob = da8xx_ddrctl_match_knob(setting); | |
126 | if (!knob) { | |
127 | dev_warn(dev, | |
128 | "no such config option: %s\n", setting->name); | |
129 | continue; | |
130 | } | |
131 | ||
132 | if (knob->reg + sizeof(u32) > resource_size(res)) { | |
133 | dev_warn(dev, | |
134 | "register offset of '%s' exceeds mapped memory size\n", | |
135 | knob->name); | |
136 | continue; | |
137 | } | |
138 | ||
139 | reg = readl(ddrctl + knob->reg); | |
140 | reg &= knob->mask; | |
141 | reg |= setting->val << knob->shift; | |
142 | ||
143 | dev_dbg(dev, "writing 0x%08x to %s\n", reg, setting->name); | |
144 | ||
145 | writel(reg, ddrctl + knob->reg); | |
146 | } | |
147 | ||
148 | return 0; | |
149 | } | |
150 | ||
151 | static const struct of_device_id da8xx_ddrctl_of_match[] = { | |
152 | { .compatible = "ti,da850-ddr-controller", }, | |
153 | { }, | |
154 | }; | |
155 | ||
156 | static struct platform_driver da8xx_ddrctl_driver = { | |
157 | .probe = da8xx_ddrctl_probe, | |
158 | .driver = { | |
159 | .name = "da850-ddr-controller", | |
160 | .of_match_table = da8xx_ddrctl_of_match, | |
161 | }, | |
162 | }; | |
163 | module_platform_driver(da8xx_ddrctl_driver); | |
164 | ||
165 | MODULE_AUTHOR("Bartosz Golaszewski <bgolaszewski@baylibre.com>"); | |
166 | MODULE_DESCRIPTION("TI da8xx DDR2/mDDR controller driver"); | |
167 | MODULE_LICENSE("GPL v2"); |