1 // SPDX-License-Identifier: GPL-2.0-only
2 // Copyright (C) 2013 Broadcom Corporation
3 
4 #include <linux/kernel.h>
5 #include <linux/module.h>
6 #include <linux/delay.h>
7 #include <linux/highmem.h>
8 #include <linux/platform_device.h>
9 #include <linux/mmc/host.h>
10 #include <linux/io.h>
11 #include <linux/clk.h>
12 #include <linux/regulator/consumer.h>
13 #include <linux/of.h>
14 #include <linux/mmc/slot-gpio.h>
15 
16 #include "sdhci-pltfm.h"
17 #include "sdhci.h"
18 
19 #define SDHCI_SOFT_RESET			0x01000000
20 #define KONA_SDHOST_CORECTRL			0x8000
21 #define KONA_SDHOST_CD_PINCTRL			0x00000008
22 #define KONA_SDHOST_STOP_HCLK			0x00000004
23 #define KONA_SDHOST_RESET			0x00000002
24 #define KONA_SDHOST_EN				0x00000001
25 
26 #define KONA_SDHOST_CORESTAT			0x8004
27 #define KONA_SDHOST_WP				0x00000002
28 #define KONA_SDHOST_CD_SW			0x00000001
29 
30 #define KONA_SDHOST_COREIMR			0x8008
31 #define KONA_SDHOST_IP				0x00000001
32 
33 #define KONA_SDHOST_COREISR			0x800C
34 #define KONA_SDHOST_COREIMSR			0x8010
35 #define KONA_SDHOST_COREDBG1			0x8014
36 #define KONA_SDHOST_COREGPO_MASK		0x8018
37 
38 #define SD_DETECT_GPIO_DEBOUNCE_128MS		128
39 
40 #define KONA_MMC_AUTOSUSPEND_DELAY		(50)
41 
42 struct sdhci_bcm_kona_dev {
43 	struct mutex	write_lock; /* protect back to back writes */
44 };
45 
46 
sdhci_bcm_kona_sd_reset(struct sdhci_host * host)47 static int sdhci_bcm_kona_sd_reset(struct sdhci_host *host)
48 {
49 	unsigned int val;
50 	unsigned long timeout;
51 
52 	/* This timeout should be sufficent for core to reset */
53 	timeout = jiffies + msecs_to_jiffies(100);
54 
55 	/* reset the host using the top level reset */
56 	val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
57 	val |= KONA_SDHOST_RESET;
58 	sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
59 
60 	while (!(sdhci_readl(host, KONA_SDHOST_CORECTRL) & KONA_SDHOST_RESET)) {
61 		if (time_is_before_jiffies(timeout)) {
62 			pr_err("Error: sd host is stuck in reset!!!\n");
63 			return -EFAULT;
64 		}
65 	}
66 
67 	/* bring the host out of reset */
68 	val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
69 	val &= ~KONA_SDHOST_RESET;
70 
71 	/*
72 	 * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
73 	 * Back-to-Back writes to same register needs delay when SD bus clock
74 	 * is very low w.r.t AHB clock, mainly during boot-time and during card
75 	 * insert-removal.
76 	 */
77 	usleep_range(1000, 5000);
78 	sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
79 
80 	return 0;
81 }
82 
sdhci_bcm_kona_sd_init(struct sdhci_host * host)83 static void sdhci_bcm_kona_sd_init(struct sdhci_host *host)
84 {
85 	unsigned int val;
86 
87 	/* enable the interrupt from the IP core */
88 	val = sdhci_readl(host, KONA_SDHOST_COREIMR);
89 	val |= KONA_SDHOST_IP;
90 	sdhci_writel(host, val, KONA_SDHOST_COREIMR);
91 
92 	/* Enable the AHB clock gating module to the host */
93 	val = sdhci_readl(host, KONA_SDHOST_CORECTRL);
94 	val |= KONA_SDHOST_EN;
95 
96 	/*
97 	 * Back-to-Back register write needs a delay of 1ms at bootup (min 10uS)
98 	 * Back-to-Back writes to same register needs delay when SD bus clock
99 	 * is very low w.r.t AHB clock, mainly during boot-time and during card
100 	 * insert-removal.
101 	 */
102 	usleep_range(1000, 5000);
103 	sdhci_writel(host, val, KONA_SDHOST_CORECTRL);
104 }
105 
106 /*
107  * Software emulation of the SD card insertion/removal. Set insert=1 for insert
108  * and insert=0 for removal. The card detection is done by GPIO. For Broadcom
109  * IP to function properly the bit 0 of CORESTAT register needs to be set/reset
110  * to generate the CD IRQ handled in sdhci.c which schedules card_tasklet.
111  */
sdhci_bcm_kona_sd_card_emulate(struct sdhci_host * host,int insert)112 static int sdhci_bcm_kona_sd_card_emulate(struct sdhci_host *host, int insert)
113 {
114 	struct sdhci_pltfm_host *pltfm_priv = sdhci_priv(host);
115 	struct sdhci_bcm_kona_dev *kona_dev = sdhci_pltfm_priv(pltfm_priv);
116 	u32 val;
117 
118 	/*
119 	 * Back-to-Back register write needs a delay of min 10uS.
120 	 * Back-to-Back writes to same register needs delay when SD bus clock
121 	 * is very low w.r.t AHB clock, mainly during boot-time and during card
122 	 * insert-removal.
123 	 * We keep 20uS
124 	 */
125 	mutex_lock(&kona_dev->write_lock);
126 	udelay(20);
127 	val = sdhci_readl(host, KONA_SDHOST_CORESTAT);
128 
129 	if (insert) {
130 		int ret;
131 
132 		ret = mmc_gpio_get_ro(host->mmc);
133 		if (ret >= 0)
134 			val = (val & ~KONA_SDHOST_WP) |
135 				((ret) ? KONA_SDHOST_WP : 0);
136 
137 		val |= KONA_SDHOST_CD_SW;
138 		sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
139 	} else {
140 		val &= ~KONA_SDHOST_CD_SW;
141 		sdhci_writel(host, val, KONA_SDHOST_CORESTAT);
142 	}
143 	mutex_unlock(&kona_dev->write_lock);
144 
145 	return 0;
146 }
147 
148 /*
149  * SD card interrupt event callback
150  */
sdhci_bcm_kona_card_event(struct sdhci_host * host)151 static void sdhci_bcm_kona_card_event(struct sdhci_host *host)
152 {
153 	if (mmc_gpio_get_cd(host->mmc) > 0) {
154 		dev_dbg(mmc_dev(host->mmc),
155 			"card inserted\n");
156 		sdhci_bcm_kona_sd_card_emulate(host, 1);
157 	} else {
158 		dev_dbg(mmc_dev(host->mmc),
159 			"card removed\n");
160 		sdhci_bcm_kona_sd_card_emulate(host, 0);
161 	}
162 }
163 
sdhci_bcm_kona_init_74_clocks(struct sdhci_host * host,u8 power_mode)164 static void sdhci_bcm_kona_init_74_clocks(struct sdhci_host *host,
165 				u8 power_mode)
166 {
167 	/*
168 	 *  JEDEC and SD spec specify supplying 74 continuous clocks to
169 	 * device after power up. With minimum bus (100KHz) that
170 	 * translates to 740us
171 	 */
172 	if (power_mode != MMC_POWER_OFF)
173 		udelay(740);
174 }
175 
176 static const struct sdhci_ops sdhci_bcm_kona_ops = {
177 	.set_clock = sdhci_set_clock,
178 	.get_max_clock = sdhci_pltfm_clk_get_max_clock,
179 	.get_timeout_clock = sdhci_pltfm_clk_get_max_clock,
180 	.platform_send_init_74_clocks = sdhci_bcm_kona_init_74_clocks,
181 	.set_bus_width = sdhci_set_bus_width,
182 	.reset = sdhci_reset,
183 	.set_uhs_signaling = sdhci_set_uhs_signaling,
184 	.card_event = sdhci_bcm_kona_card_event,
185 };
186 
187 static const struct sdhci_pltfm_data sdhci_pltfm_data_kona = {
188 	.ops    = &sdhci_bcm_kona_ops,
189 	.quirks = SDHCI_QUIRK_NO_CARD_NO_RESET |
190 		SDHCI_QUIRK_BROKEN_TIMEOUT_VAL | SDHCI_QUIRK_32BIT_DMA_ADDR |
191 		SDHCI_QUIRK_32BIT_DMA_SIZE | SDHCI_QUIRK_32BIT_ADMA_SIZE |
192 		SDHCI_QUIRK_FORCE_BLK_SZ_2048 |
193 		SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN,
194 };
195 
196 static const struct of_device_id sdhci_bcm_kona_of_match[] = {
197 	{ .compatible = "brcm,kona-sdhci"},
198 	{ .compatible = "bcm,kona-sdhci"}, /* deprecated name */
199 	{}
200 };
201 MODULE_DEVICE_TABLE(of, sdhci_bcm_kona_of_match);
202 
sdhci_bcm_kona_probe(struct platform_device * pdev)203 static int sdhci_bcm_kona_probe(struct platform_device *pdev)
204 {
205 	struct sdhci_bcm_kona_dev *kona_dev = NULL;
206 	struct sdhci_pltfm_host *pltfm_priv;
207 	struct device *dev = &pdev->dev;
208 	struct sdhci_host *host;
209 	int ret;
210 
211 	ret = 0;
212 
213 	host = sdhci_pltfm_init(pdev, &sdhci_pltfm_data_kona,
214 			sizeof(*kona_dev));
215 	if (IS_ERR(host))
216 		return PTR_ERR(host);
217 
218 	dev_dbg(dev, "%s: inited. IOADDR=%p\n", __func__, host->ioaddr);
219 
220 	pltfm_priv = sdhci_priv(host);
221 
222 	kona_dev = sdhci_pltfm_priv(pltfm_priv);
223 	mutex_init(&kona_dev->write_lock);
224 
225 	ret = mmc_of_parse(host->mmc);
226 	if (ret)
227 		goto err_pltfm_free;
228 
229 	if (!host->mmc->f_max) {
230 		dev_err(&pdev->dev, "Missing max-freq for SDHCI cfg\n");
231 		ret = -ENXIO;
232 		goto err_pltfm_free;
233 	}
234 
235 	/* Get and enable the core clock */
236 	pltfm_priv->clk = devm_clk_get(dev, NULL);
237 	if (IS_ERR(pltfm_priv->clk)) {
238 		dev_err(dev, "Failed to get core clock\n");
239 		ret = PTR_ERR(pltfm_priv->clk);
240 		goto err_pltfm_free;
241 	}
242 
243 	ret = clk_set_rate(pltfm_priv->clk, host->mmc->f_max);
244 	if (ret) {
245 		dev_err(dev, "Failed to set rate core clock\n");
246 		goto err_pltfm_free;
247 	}
248 
249 	ret = clk_prepare_enable(pltfm_priv->clk);
250 	if (ret) {
251 		dev_err(dev, "Failed to enable core clock\n");
252 		goto err_pltfm_free;
253 	}
254 
255 	dev_dbg(dev, "non-removable=%c\n",
256 		mmc_card_is_removable(host->mmc) ? 'N' : 'Y');
257 	dev_dbg(dev, "cd_gpio %c, wp_gpio %c\n",
258 		(mmc_gpio_get_cd(host->mmc) != -ENOSYS) ? 'Y' : 'N',
259 		(mmc_gpio_get_ro(host->mmc) != -ENOSYS) ? 'Y' : 'N');
260 
261 	if (!mmc_card_is_removable(host->mmc))
262 		host->quirks |= SDHCI_QUIRK_BROKEN_CARD_DETECTION;
263 
264 	dev_dbg(dev, "is_8bit=%c\n",
265 		(host->mmc->caps & MMC_CAP_8_BIT_DATA) ? 'Y' : 'N');
266 
267 	ret = sdhci_bcm_kona_sd_reset(host);
268 	if (ret)
269 		goto err_clk_disable;
270 
271 	sdhci_bcm_kona_sd_init(host);
272 
273 	ret = sdhci_add_host(host);
274 	if (ret)
275 		goto err_reset;
276 
277 	/* if device is eMMC, emulate card insert right here */
278 	if (!mmc_card_is_removable(host->mmc)) {
279 		ret = sdhci_bcm_kona_sd_card_emulate(host, 1);
280 		if (ret) {
281 			dev_err(dev,
282 				"unable to emulate card insertion\n");
283 			goto err_remove_host;
284 		}
285 	}
286 	/*
287 	 * Since the card detection GPIO interrupt is configured to be
288 	 * edge sensitive, check the initial GPIO value here, emulate
289 	 * only if the card is present
290 	 */
291 	if (mmc_gpio_get_cd(host->mmc) > 0)
292 		sdhci_bcm_kona_sd_card_emulate(host, 1);
293 
294 	dev_dbg(dev, "initialized properly\n");
295 	return 0;
296 
297 err_remove_host:
298 	sdhci_remove_host(host, 0);
299 
300 err_reset:
301 	sdhci_bcm_kona_sd_reset(host);
302 
303 err_clk_disable:
304 	clk_disable_unprepare(pltfm_priv->clk);
305 
306 err_pltfm_free:
307 	sdhci_pltfm_free(pdev);
308 
309 	dev_err(dev, "Probing of sdhci-pltfm failed: %d\n", ret);
310 	return ret;
311 }
312 
sdhci_bcm_kona_remove(struct platform_device * pdev)313 static void sdhci_bcm_kona_remove(struct platform_device *pdev)
314 {
315 	struct sdhci_host *host = platform_get_drvdata(pdev);
316 	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
317 	struct clk *clk = pltfm_host->clk;
318 
319 	sdhci_pltfm_remove(pdev);
320 	clk_disable_unprepare(clk);
321 }
322 
323 static struct platform_driver sdhci_bcm_kona_driver = {
324 	.driver		= {
325 		.name	= "sdhci-kona",
326 		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
327 		.pm	= &sdhci_pltfm_pmops,
328 		.of_match_table = sdhci_bcm_kona_of_match,
329 	},
330 	.probe		= sdhci_bcm_kona_probe,
331 	.remove_new	= sdhci_bcm_kona_remove,
332 };
333 module_platform_driver(sdhci_bcm_kona_driver);
334 
335 MODULE_DESCRIPTION("SDHCI driver for Broadcom Kona platform");
336 MODULE_AUTHOR("Broadcom");
337 MODULE_LICENSE("GPL v2");
338