1 /*
2 * Support of SDHCI platform devices for Microchip PIC32.
3 *
4 * Copyright (C) 2015 Microchip
5 * Andrei Pistirica, Paul Thacker
6 *
7 * Inspired by sdhci-pltfm.c
8 *
9 * This file is licensed under the terms of the GNU General Public
10 * License version 2. This program is licensed "as is" without any
11 * warranty of any kind, whether express or implied.
12 */
13
14 #include <linux/clk.h>
15 #include <linux/delay.h>
16 #include <linux/highmem.h>
17 #include <linux/module.h>
18 #include <linux/interrupt.h>
19 #include <linux/irq.h>
20 #include <linux/of.h>
21 #include <linux/platform_device.h>
22 #include <linux/pm.h>
23 #include <linux/slab.h>
24 #include <linux/mmc/host.h>
25 #include <linux/io.h>
26 #include "sdhci.h"
27 #include "sdhci-pltfm.h"
28 #include <linux/platform_data/sdhci-pic32.h>
29
30 #define SDH_SHARED_BUS_CTRL 0x000000E0
31 #define SDH_SHARED_BUS_NR_CLK_PINS_MASK 0x7
32 #define SDH_SHARED_BUS_NR_IRQ_PINS_MASK 0x30
33 #define SDH_SHARED_BUS_CLK_PINS 0x10
34 #define SDH_SHARED_BUS_IRQ_PINS 0x14
35 #define SDH_CAPS_SDH_SLOT_TYPE_MASK 0xC0000000
36 #define SDH_SLOT_TYPE_REMOVABLE 0x0
37 #define SDH_SLOT_TYPE_EMBEDDED 0x1
38 #define SDH_SLOT_TYPE_SHARED_BUS 0x2
39 #define SDHCI_CTRL_CDSSEL 0x80
40 #define SDHCI_CTRL_CDTLVL 0x40
41
42 #define ADMA_FIFO_RD_THSHLD 512
43 #define ADMA_FIFO_WR_THSHLD 512
44
45 struct pic32_sdhci_priv {
46 struct platform_device *pdev;
47 struct clk *sys_clk;
48 struct clk *base_clk;
49 };
50
pic32_sdhci_get_max_clock(struct sdhci_host * host)51 static unsigned int pic32_sdhci_get_max_clock(struct sdhci_host *host)
52 {
53 struct pic32_sdhci_priv *sdhci_pdata = sdhci_priv(host);
54
55 return clk_get_rate(sdhci_pdata->base_clk);
56 }
57
pic32_sdhci_set_bus_width(struct sdhci_host * host,int width)58 static void pic32_sdhci_set_bus_width(struct sdhci_host *host, int width)
59 {
60 u8 ctrl;
61
62 ctrl = sdhci_readb(host, SDHCI_HOST_CONTROL);
63 if (width == MMC_BUS_WIDTH_8) {
64 ctrl &= ~SDHCI_CTRL_4BITBUS;
65 if (host->version >= SDHCI_SPEC_300)
66 ctrl |= SDHCI_CTRL_8BITBUS;
67 } else {
68 if (host->version >= SDHCI_SPEC_300)
69 ctrl &= ~SDHCI_CTRL_8BITBUS;
70 if (width == MMC_BUS_WIDTH_4)
71 ctrl |= SDHCI_CTRL_4BITBUS;
72 else
73 ctrl &= ~SDHCI_CTRL_4BITBUS;
74 }
75
76 /* CD select and test bits must be set for errata workaround. */
77 ctrl &= ~SDHCI_CTRL_CDTLVL;
78 ctrl |= SDHCI_CTRL_CDSSEL;
79 sdhci_writeb(host, ctrl, SDHCI_HOST_CONTROL);
80 }
81
pic32_sdhci_get_ro(struct sdhci_host * host)82 static unsigned int pic32_sdhci_get_ro(struct sdhci_host *host)
83 {
84 /*
85 * The SDHCI_WRITE_PROTECT bit is unstable on current hardware so we
86 * can't depend on its value in any way.
87 */
88 return 0;
89 }
90
91 static const struct sdhci_ops pic32_sdhci_ops = {
92 .get_max_clock = pic32_sdhci_get_max_clock,
93 .set_clock = sdhci_set_clock,
94 .set_bus_width = pic32_sdhci_set_bus_width,
95 .reset = sdhci_reset,
96 .set_uhs_signaling = sdhci_set_uhs_signaling,
97 .get_ro = pic32_sdhci_get_ro,
98 };
99
100 static const struct sdhci_pltfm_data sdhci_pic32_pdata = {
101 .ops = &pic32_sdhci_ops,
102 .quirks = SDHCI_QUIRK_NO_HISPD_BIT,
103 .quirks2 = SDHCI_QUIRK2_NO_1_8_V,
104 };
105
pic32_sdhci_shared_bus(struct platform_device * pdev)106 static void pic32_sdhci_shared_bus(struct platform_device *pdev)
107 {
108 struct sdhci_host *host = platform_get_drvdata(pdev);
109 u32 bus = readl(host->ioaddr + SDH_SHARED_BUS_CTRL);
110 u32 clk_pins = (bus & SDH_SHARED_BUS_NR_CLK_PINS_MASK) >> 0;
111 u32 irq_pins = (bus & SDH_SHARED_BUS_NR_IRQ_PINS_MASK) >> 4;
112
113 /* select first clock */
114 if (clk_pins & 1)
115 bus |= (1 << SDH_SHARED_BUS_CLK_PINS);
116
117 /* select first interrupt */
118 if (irq_pins & 1)
119 bus |= (1 << SDH_SHARED_BUS_IRQ_PINS);
120
121 writel(bus, host->ioaddr + SDH_SHARED_BUS_CTRL);
122 }
123
pic32_sdhci_probe_platform(struct platform_device * pdev,struct pic32_sdhci_priv * pdata)124 static void pic32_sdhci_probe_platform(struct platform_device *pdev,
125 struct pic32_sdhci_priv *pdata)
126 {
127 u32 caps_slot_type;
128 struct sdhci_host *host = platform_get_drvdata(pdev);
129
130 /* Check card slot connected on shared bus. */
131 host->caps = readl(host->ioaddr + SDHCI_CAPABILITIES);
132 caps_slot_type = (host->caps & SDH_CAPS_SDH_SLOT_TYPE_MASK) >> 30;
133 if (caps_slot_type == SDH_SLOT_TYPE_SHARED_BUS)
134 pic32_sdhci_shared_bus(pdev);
135 }
136
pic32_sdhci_probe(struct platform_device * pdev)137 static int pic32_sdhci_probe(struct platform_device *pdev)
138 {
139 struct sdhci_host *host;
140 struct sdhci_pltfm_host *pltfm_host;
141 struct pic32_sdhci_priv *sdhci_pdata;
142 struct pic32_sdhci_platform_data *plat_data;
143 int ret;
144
145 host = sdhci_pltfm_init(pdev, &sdhci_pic32_pdata,
146 sizeof(struct pic32_sdhci_priv));
147 if (IS_ERR(host)) {
148 ret = PTR_ERR(host);
149 goto err;
150 }
151
152 pltfm_host = sdhci_priv(host);
153 sdhci_pdata = sdhci_pltfm_priv(pltfm_host);
154
155 plat_data = pdev->dev.platform_data;
156 if (plat_data && plat_data->setup_dma) {
157 ret = plat_data->setup_dma(ADMA_FIFO_RD_THSHLD,
158 ADMA_FIFO_WR_THSHLD);
159 if (ret)
160 goto err_host;
161 }
162
163 sdhci_pdata->sys_clk = devm_clk_get(&pdev->dev, "sys_clk");
164 if (IS_ERR(sdhci_pdata->sys_clk)) {
165 ret = PTR_ERR(sdhci_pdata->sys_clk);
166 dev_err(&pdev->dev, "Error getting clock\n");
167 goto err_host;
168 }
169
170 ret = clk_prepare_enable(sdhci_pdata->sys_clk);
171 if (ret) {
172 dev_err(&pdev->dev, "Error enabling clock\n");
173 goto err_host;
174 }
175
176 sdhci_pdata->base_clk = devm_clk_get(&pdev->dev, "base_clk");
177 if (IS_ERR(sdhci_pdata->base_clk)) {
178 ret = PTR_ERR(sdhci_pdata->base_clk);
179 dev_err(&pdev->dev, "Error getting clock\n");
180 goto err_sys_clk;
181 }
182
183 ret = clk_prepare_enable(sdhci_pdata->base_clk);
184 if (ret) {
185 dev_err(&pdev->dev, "Error enabling clock\n");
186 goto err_base_clk;
187 }
188
189 ret = mmc_of_parse(host->mmc);
190 if (ret)
191 goto err_base_clk;
192
193 pic32_sdhci_probe_platform(pdev, sdhci_pdata);
194
195 ret = sdhci_add_host(host);
196 if (ret)
197 goto err_base_clk;
198
199 dev_info(&pdev->dev, "Successfully added sdhci host\n");
200 return 0;
201
202 err_base_clk:
203 clk_disable_unprepare(sdhci_pdata->base_clk);
204 err_sys_clk:
205 clk_disable_unprepare(sdhci_pdata->sys_clk);
206 err_host:
207 sdhci_pltfm_free(pdev);
208 err:
209 dev_err(&pdev->dev, "pic32-sdhci probe failed: %d\n", ret);
210 return ret;
211 }
212
pic32_sdhci_remove(struct platform_device * pdev)213 static int pic32_sdhci_remove(struct platform_device *pdev)
214 {
215 struct sdhci_host *host = platform_get_drvdata(pdev);
216 struct pic32_sdhci_priv *sdhci_pdata = sdhci_priv(host);
217 u32 scratch;
218
219 scratch = readl(host->ioaddr + SDHCI_INT_STATUS);
220 sdhci_remove_host(host, scratch == (u32)~0);
221 clk_disable_unprepare(sdhci_pdata->base_clk);
222 clk_disable_unprepare(sdhci_pdata->sys_clk);
223 sdhci_pltfm_free(pdev);
224
225 return 0;
226 }
227
228 static const struct of_device_id pic32_sdhci_id_table[] = {
229 { .compatible = "microchip,pic32mzda-sdhci" },
230 {}
231 };
232 MODULE_DEVICE_TABLE(of, pic32_sdhci_id_table);
233
234 static struct platform_driver pic32_sdhci_driver = {
235 .driver = {
236 .name = "pic32-sdhci",
237 .probe_type = PROBE_PREFER_ASYNCHRONOUS,
238 .of_match_table = of_match_ptr(pic32_sdhci_id_table),
239 },
240 .probe = pic32_sdhci_probe,
241 .remove = pic32_sdhci_remove,
242 };
243
244 module_platform_driver(pic32_sdhci_driver);
245
246 MODULE_DESCRIPTION("Microchip PIC32 SDHCI driver");
247 MODULE_AUTHOR("Pistirica Sorin Andrei & Sandeep Sheriker");
248 MODULE_LICENSE("GPL v2");
249