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/bitfield.h>
9 #include <linux/clk.h>
10 #include <linux/delay.h>
11 #include <linux/mfd/syscon.h>
12 #include <linux/mmc/host.h>
13 #include <linux/module.h>
14 #include <linux/of_address.h>
15 #include <linux/platform_device.h>
16 #include <linux/regmap.h>
17
18 #include "dw_mmc.h"
19 #include "dw_mmc-pltfm.h"
20
21 #define ALL_INT_CLR 0x1ffff
22 #define MAX_DELAY_CHAIN 32
23
24 #define STARFIVE_SMPL_PHASE GENMASK(20, 16)
25
dw_mci_starfive_set_ios(struct dw_mci * host,struct mmc_ios * ios)26 static void dw_mci_starfive_set_ios(struct dw_mci *host, struct mmc_ios *ios)
27 {
28 int ret;
29 unsigned int clock;
30
31 if (ios->timing == MMC_TIMING_MMC_DDR52 || ios->timing == MMC_TIMING_UHS_DDR50) {
32 clock = (ios->clock > 50000000 && ios->clock <= 52000000) ? 100000000 : ios->clock;
33 ret = clk_set_rate(host->ciu_clk, clock);
34 if (ret)
35 dev_dbg(host->dev, "Use an external frequency divider %uHz\n", ios->clock);
36 host->bus_hz = clk_get_rate(host->ciu_clk);
37 } else {
38 dev_dbg(host->dev, "Using the internal divider\n");
39 }
40 }
41
dw_mci_starfive_set_sample_phase(struct dw_mci * host,u32 smpl_phase)42 static void dw_mci_starfive_set_sample_phase(struct dw_mci *host, u32 smpl_phase)
43 {
44 /* change driver phase and sample phase */
45 u32 reg_value = mci_readl(host, UHS_REG_EXT);
46
47 /* In UHS_REG_EXT, only 5 bits valid in DRV_PHASE and SMPL_PHASE */
48 reg_value &= ~STARFIVE_SMPL_PHASE;
49 reg_value |= FIELD_PREP(STARFIVE_SMPL_PHASE, smpl_phase);
50 mci_writel(host, UHS_REG_EXT, reg_value);
51
52 /* We should delay 1ms wait for timing setting finished. */
53 mdelay(1);
54 }
55
dw_mci_starfive_execute_tuning(struct dw_mci_slot * slot,u32 opcode)56 static int dw_mci_starfive_execute_tuning(struct dw_mci_slot *slot,
57 u32 opcode)
58 {
59 static const int grade = MAX_DELAY_CHAIN;
60 struct dw_mci *host = slot->host;
61 int smpl_phase, smpl_raise = -1, smpl_fall = -1;
62 int ret;
63
64 for (smpl_phase = 0; smpl_phase < grade; smpl_phase++) {
65 dw_mci_starfive_set_sample_phase(host, smpl_phase);
66 mci_writel(host, RINTSTS, ALL_INT_CLR);
67
68 ret = mmc_send_tuning(slot->mmc, opcode, NULL);
69
70 if (!ret && smpl_raise < 0) {
71 smpl_raise = smpl_phase;
72 } else if (ret && smpl_raise >= 0) {
73 smpl_fall = smpl_phase - 1;
74 break;
75 }
76 }
77
78 if (smpl_phase >= grade)
79 smpl_fall = grade - 1;
80
81 if (smpl_raise < 0) {
82 smpl_phase = 0;
83 dev_err(host->dev, "No valid delay chain! use default\n");
84 ret = -EINVAL;
85 goto out;
86 }
87
88 smpl_phase = (smpl_raise + smpl_fall) / 2;
89 dev_dbg(host->dev, "Found valid delay chain! use it [delay=%d]\n", smpl_phase);
90 ret = 0;
91
92 out:
93 dw_mci_starfive_set_sample_phase(host, smpl_phase);
94 mci_writel(host, RINTSTS, ALL_INT_CLR);
95 return ret;
96 }
97
98 static const struct dw_mci_drv_data starfive_data = {
99 .common_caps = MMC_CAP_CMD23,
100 .set_ios = dw_mci_starfive_set_ios,
101 .execute_tuning = dw_mci_starfive_execute_tuning,
102 };
103
104 static const struct of_device_id dw_mci_starfive_match[] = {
105 { .compatible = "starfive,jh7110-mmc",
106 .data = &starfive_data },
107 {},
108 };
109 MODULE_DEVICE_TABLE(of, dw_mci_starfive_match);
110
dw_mci_starfive_probe(struct platform_device * pdev)111 static int dw_mci_starfive_probe(struct platform_device *pdev)
112 {
113 return dw_mci_pltfm_register(pdev, &starfive_data);
114 }
115
116 static struct platform_driver dw_mci_starfive_driver = {
117 .probe = dw_mci_starfive_probe,
118 .remove_new = dw_mci_pltfm_remove,
119 .driver = {
120 .name = "dwmmc_starfive",
121 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
122 .of_match_table = dw_mci_starfive_match,
123 },
124 };
125 module_platform_driver(dw_mci_starfive_driver);
126
127 MODULE_DESCRIPTION("StarFive JH7110 Specific DW-MSHC Driver Extension");
128 MODULE_LICENSE("GPL");
129 MODULE_ALIAS("platform:dwmmc_starfive");
130