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1a94715d SW |
1 | /* |
2 | * BCM2835 SDHCI | |
3 | * Copyright (C) 2012 Stephen Warren | |
4 | * Based on U-Boot's MMC driver for the BCM2835 by Oleksandr Tymoshenko & me | |
5 | * Portions of the code there were obviously based on the Linux kernel at: | |
6 | * git://github.com/raspberrypi/linux.git rpi-3.6.y | |
7 | * commit f5b930b "Main bcm2708 linux port" signed-off-by Dom Cobley. | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify it | |
10 | * under the terms and conditions of the GNU General Public License, | |
11 | * version 2, as published by the Free Software Foundation. | |
12 | * | |
13 | * This program is distributed in the hope it will be useful, but WITHOUT | |
14 | * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or | |
15 | * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for | |
16 | * more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program. If not, see <http://www.gnu.org/licenses/>. | |
20 | */ | |
21 | ||
22 | #include <linux/delay.h> | |
23 | #include <linux/module.h> | |
24 | #include <linux/mmc/host.h> | |
25 | #include "sdhci-pltfm.h" | |
26 | ||
27 | /* | |
28 | * 400KHz is max freq for card ID etc. Use that as min card clock. We need to | |
29 | * know the min to enable static calculation of max BCM2835_SDHCI_WRITE_DELAY. | |
30 | */ | |
31 | #define MIN_FREQ 400000 | |
32 | ||
33 | /* | |
34 | * The Arasan has a bugette whereby it may lose the content of successive | |
35 | * writes to registers that are within two SD-card clock cycles of each other | |
36 | * (a clock domain crossing problem). It seems, however, that the data | |
37 | * register does not have this problem, which is just as well - otherwise we'd | |
38 | * have to nobble the DMA engine too. | |
39 | * | |
40 | * This should probably be dynamically calculated based on the actual card | |
41 | * frequency. However, this is the longest we'll have to wait, and doesn't | |
42 | * seem to slow access down too much, so the added complexity doesn't seem | |
43 | * worth it for now. | |
44 | * | |
45 | * 1/MIN_FREQ is (max) time per tick of eMMC clock. | |
46 | * 2/MIN_FREQ is time for two ticks. | |
47 | * Multiply by 1000000 to get uS per two ticks. | |
48 | * *1000000 for uSecs. | |
49 | * +1 for hack rounding. | |
50 | */ | |
51 | #define BCM2835_SDHCI_WRITE_DELAY (((2 * 1000000) / MIN_FREQ) + 1) | |
52 | ||
53 | struct bcm2835_sdhci { | |
1a94715d SW |
54 | u32 shadow; |
55 | }; | |
56 | ||
57 | static void bcm2835_sdhci_writel(struct sdhci_host *host, u32 val, int reg) | |
58 | { | |
59 | writel(val, host->ioaddr + reg); | |
60 | ||
61 | udelay(BCM2835_SDHCI_WRITE_DELAY); | |
62 | } | |
63 | ||
64 | static inline u32 bcm2835_sdhci_readl(struct sdhci_host *host, int reg) | |
65 | { | |
66 | u32 val = readl(host->ioaddr + reg); | |
67 | ||
68 | if (reg == SDHCI_CAPABILITIES) | |
69 | val |= SDHCI_CAN_VDD_330; | |
70 | ||
71 | return val; | |
72 | } | |
73 | ||
74 | static void bcm2835_sdhci_writew(struct sdhci_host *host, u16 val, int reg) | |
75 | { | |
76 | struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host); | |
77 | struct bcm2835_sdhci *bcm2835_host = pltfm_host->priv; | |
78 | u32 oldval = (reg == SDHCI_COMMAND) ? bcm2835_host->shadow : | |
79 | bcm2835_sdhci_readl(host, reg & ~3); | |
80 | u32 word_num = (reg >> 1) & 1; | |
81 | u32 word_shift = word_num * 16; | |
82 | u32 mask = 0xffff << word_shift; | |
83 | u32 newval = (oldval & ~mask) | (val << word_shift); | |
84 | ||
85 | if (reg == SDHCI_TRANSFER_MODE) | |
86 | bcm2835_host->shadow = newval; | |
87 | else | |
88 | bcm2835_sdhci_writel(host, newval, reg & ~3); | |
89 | } | |
90 | ||
91 | static u16 bcm2835_sdhci_readw(struct sdhci_host *host, int reg) | |
92 | { | |
93 | u32 val = bcm2835_sdhci_readl(host, (reg & ~3)); | |
94 | u32 word_num = (reg >> 1) & 1; | |
95 | u32 word_shift = word_num * 16; | |
96 | u32 word = (val >> word_shift) & 0xffff; | |
97 | ||
98 | return word; | |
99 | } | |
100 | ||
101 | static void bcm2835_sdhci_writeb(struct sdhci_host *host, u8 val, int reg) | |
102 | { | |
103 | u32 oldval = bcm2835_sdhci_readl(host, reg & ~3); | |
104 | u32 byte_num = reg & 3; | |
105 | u32 byte_shift = byte_num * 8; | |
106 | u32 mask = 0xff << byte_shift; | |
107 | u32 newval = (oldval & ~mask) | (val << byte_shift); | |
108 | ||
109 | bcm2835_sdhci_writel(host, newval, reg & ~3); | |
110 | } | |
111 | ||
112 | static u8 bcm2835_sdhci_readb(struct sdhci_host *host, int reg) | |
113 | { | |
114 | u32 val = bcm2835_sdhci_readl(host, (reg & ~3)); | |
115 | u32 byte_num = reg & 3; | |
116 | u32 byte_shift = byte_num * 8; | |
117 | u32 byte = (val >> byte_shift) & 0xff; | |
118 | ||
119 | return byte; | |
120 | } | |
121 | ||
1a94715d SW |
122 | unsigned int bcm2835_sdhci_get_min_clock(struct sdhci_host *host) |
123 | { | |
124 | return MIN_FREQ; | |
125 | } | |
126 | ||
1a94715d SW |
127 | static struct sdhci_ops bcm2835_sdhci_ops = { |
128 | .write_l = bcm2835_sdhci_writel, | |
129 | .write_w = bcm2835_sdhci_writew, | |
130 | .write_b = bcm2835_sdhci_writeb, | |
131 | .read_l = bcm2835_sdhci_readl, | |
132 | .read_w = bcm2835_sdhci_readw, | |
133 | .read_b = bcm2835_sdhci_readb, | |
d005d943 | 134 | .get_max_clock = sdhci_pltfm_clk_get_max_clock, |
1a94715d | 135 | .get_min_clock = bcm2835_sdhci_get_min_clock, |
d005d943 | 136 | .get_timeout_clock = sdhci_pltfm_clk_get_max_clock, |
1a94715d SW |
137 | }; |
138 | ||
139 | static struct sdhci_pltfm_data bcm2835_sdhci_pdata = { | |
140 | .quirks = SDHCI_QUIRK_BROKEN_CARD_DETECTION, | |
141 | .ops = &bcm2835_sdhci_ops, | |
142 | }; | |
143 | ||
144 | static int bcm2835_sdhci_probe(struct platform_device *pdev) | |
145 | { | |
146 | struct sdhci_host *host; | |
147 | struct bcm2835_sdhci *bcm2835_host; | |
148 | struct sdhci_pltfm_host *pltfm_host; | |
149 | int ret; | |
150 | ||
151 | host = sdhci_pltfm_init(pdev, &bcm2835_sdhci_pdata); | |
152 | if (IS_ERR(host)) | |
153 | return PTR_ERR(host); | |
154 | ||
155 | bcm2835_host = devm_kzalloc(&pdev->dev, sizeof(*bcm2835_host), | |
156 | GFP_KERNEL); | |
157 | if (!bcm2835_host) { | |
158 | dev_err(mmc_dev(host->mmc), | |
159 | "failed to allocate bcm2835_sdhci\n"); | |
160 | return -ENOMEM; | |
161 | } | |
162 | ||
163 | pltfm_host = sdhci_priv(host); | |
164 | pltfm_host->priv = bcm2835_host; | |
165 | ||
d005d943 LPC |
166 | pltfm_host->clk = devm_clk_get(&pdev->dev, NULL); |
167 | if (IS_ERR(pltfm_host->clk)) { | |
168 | ret = PTR_ERR(pltfm_host->clk); | |
1a94715d SW |
169 | goto err; |
170 | } | |
171 | ||
172 | return sdhci_add_host(host); | |
173 | ||
174 | err: | |
175 | sdhci_pltfm_free(pdev); | |
176 | return ret; | |
177 | } | |
178 | ||
179 | static int bcm2835_sdhci_remove(struct platform_device *pdev) | |
180 | { | |
181 | struct sdhci_host *host = platform_get_drvdata(pdev); | |
182 | int dead = (readl(host->ioaddr + SDHCI_INT_STATUS) == 0xffffffff); | |
183 | ||
184 | sdhci_remove_host(host, dead); | |
185 | sdhci_pltfm_free(pdev); | |
186 | ||
187 | return 0; | |
188 | } | |
189 | ||
190 | static const struct of_device_id bcm2835_sdhci_of_match[] = { | |
191 | { .compatible = "brcm,bcm2835-sdhci" }, | |
192 | { } | |
193 | }; | |
194 | MODULE_DEVICE_TABLE(of, bcm2835_sdhci_of_match); | |
195 | ||
196 | static struct platform_driver bcm2835_sdhci_driver = { | |
197 | .driver = { | |
198 | .name = "sdhci-bcm2835", | |
199 | .owner = THIS_MODULE, | |
200 | .of_match_table = bcm2835_sdhci_of_match, | |
201 | .pm = SDHCI_PLTFM_PMOPS, | |
202 | }, | |
203 | .probe = bcm2835_sdhci_probe, | |
204 | .remove = bcm2835_sdhci_remove, | |
205 | }; | |
206 | module_platform_driver(bcm2835_sdhci_driver); | |
207 | ||
208 | MODULE_DESCRIPTION("BCM2835 SDHCI driver"); | |
209 | MODULE_AUTHOR("Stephen Warren"); | |
210 | MODULE_LICENSE("GPL v2"); |