1 /*
2 * SDHCI support for CNS3xxx SoC
3 *
4 * Copyright 2008 Cavium Networks
5 * Copyright 2010 MontaVista Software, LLC.
6 *
7 * Authors: Scott Shu
8 * Anton Vorontsov <avorontsov@mvista.com>
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License version 2 as
12 * published by the Free Software Foundation.
13 */
14
15 #include <linux/delay.h>
16 #include <linux/device.h>
17 #include <linux/mmc/host.h>
18 #include <linux/module.h>
19 #include "sdhci-pltfm.h"
20
sdhci_cns3xxx_get_max_clk(struct sdhci_host * host)21 static unsigned int sdhci_cns3xxx_get_max_clk(struct sdhci_host *host)
22 {
23 return 150000000;
24 }
25
sdhci_cns3xxx_set_clock(struct sdhci_host * host,unsigned int clock)26 static void sdhci_cns3xxx_set_clock(struct sdhci_host *host, unsigned int clock)
27 {
28 struct device *dev = mmc_dev(host->mmc);
29 int div = 1;
30 u16 clk;
31 unsigned long timeout;
32
33 host->mmc->actual_clock = 0;
34
35 sdhci_writew(host, 0, SDHCI_CLOCK_CONTROL);
36
37 if (clock == 0)
38 return;
39
40 while (host->max_clk / div > clock) {
41 /*
42 * On CNS3xxx divider grows linearly up to 4, and then
43 * exponentially up to 256.
44 */
45 if (div < 4)
46 div += 1;
47 else if (div < 256)
48 div *= 2;
49 else
50 break;
51 }
52
53 dev_dbg(dev, "desired SD clock: %d, actual: %d\n",
54 clock, host->max_clk / div);
55
56 /* Divide by 3 is special. */
57 if (div != 3)
58 div >>= 1;
59
60 clk = div << SDHCI_DIVIDER_SHIFT;
61 clk |= SDHCI_CLOCK_INT_EN;
62 sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
63
64 timeout = 20;
65 while (!((clk = sdhci_readw(host, SDHCI_CLOCK_CONTROL))
66 & SDHCI_CLOCK_INT_STABLE)) {
67 if (timeout == 0) {
68 dev_warn(dev, "clock is unstable");
69 break;
70 }
71 timeout--;
72 mdelay(1);
73 }
74
75 clk |= SDHCI_CLOCK_CARD_EN;
76 sdhci_writew(host, clk, SDHCI_CLOCK_CONTROL);
77 }
78
79 static const struct sdhci_ops sdhci_cns3xxx_ops = {
80 .get_max_clock = sdhci_cns3xxx_get_max_clk,
81 .set_clock = sdhci_cns3xxx_set_clock,
82 .set_bus_width = sdhci_set_bus_width,
83 .reset = sdhci_reset,
84 .set_uhs_signaling = sdhci_set_uhs_signaling,
85 };
86
87 static const struct sdhci_pltfm_data sdhci_cns3xxx_pdata = {
88 .ops = &sdhci_cns3xxx_ops,
89 .quirks = SDHCI_QUIRK_BROKEN_DMA |
90 SDHCI_QUIRK_DATA_TIMEOUT_USES_SDCLK |
91 SDHCI_QUIRK_INVERTED_WRITE_PROTECT |
92 SDHCI_QUIRK_CAP_CLOCK_BASE_BROKEN |
93 SDHCI_QUIRK_BROKEN_TIMEOUT_VAL,
94 };
95
sdhci_cns3xxx_probe(struct platform_device * pdev)96 static int sdhci_cns3xxx_probe(struct platform_device *pdev)
97 {
98 return sdhci_pltfm_register(pdev, &sdhci_cns3xxx_pdata, 0);
99 }
100
101 static struct platform_driver sdhci_cns3xxx_driver = {
102 .driver = {
103 .name = "sdhci-cns3xxx",
104 .pm = &sdhci_pltfm_pmops,
105 },
106 .probe = sdhci_cns3xxx_probe,
107 .remove = sdhci_pltfm_unregister,
108 };
109
110 module_platform_driver(sdhci_cns3xxx_driver);
111
112 MODULE_DESCRIPTION("SDHCI driver for CNS3xxx");
113 MODULE_AUTHOR("Scott Shu, "
114 "Anton Vorontsov <avorontsov@mvista.com>");
115 MODULE_LICENSE("GPL v2");
116