1 // SPDX-License-Identifier: GPL-2.0
2 /*
3 * StarFive Designware Mobile Storage Host Controller Driver
4 *
5 * Copyright (c) 2022 StarFive Technology Co., Ltd.
6 */
7
8 #include <linux/clk.h>
9 #include <linux/delay.h>
10 #include <linux/mfd/syscon.h>
11 #include <linux/mmc/host.h>
12 #include <linux/module.h>
13 #include <linux/of_address.h>
14 #include <linux/platform_device.h>
15 #include <linux/regmap.h>
16
17 #include "dw_mmc.h"
18 #include "dw_mmc-pltfm.h"
19
20 #define ALL_INT_CLR 0x1ffff
21 #define MAX_DELAY_CHAIN 32
22
23 struct starfive_priv {
24 struct device *dev;
25 struct regmap *reg_syscon;
26 u32 syscon_offset;
27 u32 syscon_shift;
28 u32 syscon_mask;
29 };
30
dw_mci_starfive_set_ios(struct dw_mci * host,struct mmc_ios * ios)31 static void dw_mci_starfive_set_ios(struct dw_mci *host, struct mmc_ios *ios)
32 {
33 int ret;
34 unsigned int clock;
35
36 if (ios->timing == MMC_TIMING_MMC_DDR52 || ios->timing == MMC_TIMING_UHS_DDR50) {
37 clock = (ios->clock > 50000000 && ios->clock <= 52000000) ? 100000000 : ios->clock;
38 ret = clk_set_rate(host->ciu_clk, clock);
39 if (ret)
40 dev_dbg(host->dev, "Use an external frequency divider %uHz\n", ios->clock);
41 host->bus_hz = clk_get_rate(host->ciu_clk);
42 } else {
43 dev_dbg(host->dev, "Using the internal divider\n");
44 }
45 }
46
dw_mci_starfive_execute_tuning(struct dw_mci_slot * slot,u32 opcode)47 static int dw_mci_starfive_execute_tuning(struct dw_mci_slot *slot,
48 u32 opcode)
49 {
50 static const int grade = MAX_DELAY_CHAIN;
51 struct dw_mci *host = slot->host;
52 struct starfive_priv *priv = host->priv;
53 int rise_point = -1, fall_point = -1;
54 int err, prev_err = 0;
55 int i;
56 bool found = 0;
57 u32 regval;
58
59 /*
60 * Use grade as the max delay chain, and use the rise_point and
61 * fall_point to ensure the best sampling point of a data input
62 * signals.
63 */
64 for (i = 0; i < grade; i++) {
65 regval = i << priv->syscon_shift;
66 err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
67 priv->syscon_mask, regval);
68 if (err)
69 return err;
70 mci_writel(host, RINTSTS, ALL_INT_CLR);
71
72 err = mmc_send_tuning(slot->mmc, opcode, NULL);
73 if (!err)
74 found = 1;
75
76 if (i > 0) {
77 if (err && !prev_err)
78 fall_point = i - 1;
79 if (!err && prev_err)
80 rise_point = i;
81 }
82
83 if (rise_point != -1 && fall_point != -1)
84 goto tuning_out;
85
86 prev_err = err;
87 err = 0;
88 }
89
90 tuning_out:
91 if (found) {
92 if (rise_point == -1)
93 rise_point = 0;
94 if (fall_point == -1)
95 fall_point = grade - 1;
96 if (fall_point < rise_point) {
97 if ((rise_point + fall_point) >
98 (grade - 1))
99 i = fall_point / 2;
100 else
101 i = (rise_point + grade - 1) / 2;
102 } else {
103 i = (rise_point + fall_point) / 2;
104 }
105
106 regval = i << priv->syscon_shift;
107 err = regmap_update_bits(priv->reg_syscon, priv->syscon_offset,
108 priv->syscon_mask, regval);
109 if (err)
110 return err;
111 mci_writel(host, RINTSTS, ALL_INT_CLR);
112
113 dev_info(host->dev, "Found valid delay chain! use it [delay=%d]\n", i);
114 } else {
115 dev_err(host->dev, "No valid delay chain! use default\n");
116 err = -EINVAL;
117 }
118
119 mci_writel(host, RINTSTS, ALL_INT_CLR);
120 return err;
121 }
122
dw_mci_starfive_parse_dt(struct dw_mci * host)123 static int dw_mci_starfive_parse_dt(struct dw_mci *host)
124 {
125 struct of_phandle_args args;
126 struct starfive_priv *priv;
127 int ret;
128
129 priv = devm_kzalloc(host->dev, sizeof(*priv), GFP_KERNEL);
130 if (!priv)
131 return -ENOMEM;
132
133 ret = of_parse_phandle_with_fixed_args(host->dev->of_node,
134 "starfive,sysreg", 3, 0, &args);
135 if (ret) {
136 dev_err(host->dev, "Failed to parse starfive,sysreg\n");
137 return -EINVAL;
138 }
139
140 priv->reg_syscon = syscon_node_to_regmap(args.np);
141 of_node_put(args.np);
142 if (IS_ERR(priv->reg_syscon))
143 return PTR_ERR(priv->reg_syscon);
144
145 priv->syscon_offset = args.args[0];
146 priv->syscon_shift = args.args[1];
147 priv->syscon_mask = args.args[2];
148
149 host->priv = priv;
150
151 return 0;
152 }
153
154 static const struct dw_mci_drv_data starfive_data = {
155 .common_caps = MMC_CAP_CMD23,
156 .set_ios = dw_mci_starfive_set_ios,
157 .parse_dt = dw_mci_starfive_parse_dt,
158 .execute_tuning = dw_mci_starfive_execute_tuning,
159 };
160
161 static const struct of_device_id dw_mci_starfive_match[] = {
162 { .compatible = "starfive,jh7110-mmc",
163 .data = &starfive_data },
164 {},
165 };
166 MODULE_DEVICE_TABLE(of, dw_mci_starfive_match);
167
dw_mci_starfive_probe(struct platform_device * pdev)168 static int dw_mci_starfive_probe(struct platform_device *pdev)
169 {
170 return dw_mci_pltfm_register(pdev, &starfive_data);
171 }
172
173 static struct platform_driver dw_mci_starfive_driver = {
174 .probe = dw_mci_starfive_probe,
175 .remove_new = dw_mci_pltfm_remove,
176 .driver = {
177 .name = "dwmmc_starfive",
178 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
179 .of_match_table = dw_mci_starfive_match,
180 },
181 };
182 module_platform_driver(dw_mci_starfive_driver);
183
184 MODULE_DESCRIPTION("StarFive JH7110 Specific DW-MSHC Driver Extension");
185 MODULE_LICENSE("GPL");
186 MODULE_ALIAS("platform:dwmmc_starfive");
187