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19#include <linux/module.h>
20#include <linux/init.h>
21#include <linux/kernel.h>
22#include <linux/clk.h>
23#include <linux/err.h>
24#include <linux/ioport.h>
25#include <linux/platform_device.h>
26#include <linux/hw_random.h>
27#include <linux/io.h>
28
29
30#define RNGA_CONTROL 0x00
31#define RNGA_STATUS 0x04
32#define RNGA_ENTROPY 0x08
33#define RNGA_OUTPUT_FIFO 0x0c
34#define RNGA_MODE 0x10
35#define RNGA_VERIFICATION_CONTROL 0x14
36#define RNGA_OSC_CONTROL_COUNTER 0x18
37#define RNGA_OSC1_COUNTER 0x1c
38#define RNGA_OSC2_COUNTER 0x20
39#define RNGA_OSC_COUNTER_STATUS 0x24
40
41
42#define RNG_ADDR_RANGE 0x28
43
44
45#define RNGA_CONTROL_SLEEP 0x00000010
46#define RNGA_CONTROL_CLEAR_INT 0x00000008
47#define RNGA_CONTROL_MASK_INTS 0x00000004
48#define RNGA_CONTROL_HIGH_ASSURANCE 0x00000002
49#define RNGA_CONTROL_GO 0x00000001
50
51#define RNGA_STATUS_LEVEL_MASK 0x0000ff00
52
53
54#define RNGA_STATUS_OSC_DEAD 0x80000000
55#define RNGA_STATUS_SLEEP 0x00000010
56#define RNGA_STATUS_ERROR_INT 0x00000008
57#define RNGA_STATUS_FIFO_UNDERFLOW 0x00000004
58#define RNGA_STATUS_LAST_READ_STATUS 0x00000002
59#define RNGA_STATUS_SECURITY_VIOLATION 0x00000001
60
61static struct platform_device *rng_dev;
62
63static int mxc_rnga_data_present(struct hwrng *rng)
64{
65 int level;
66 void __iomem *rng_base = (void __iomem *)rng->priv;
67
68
69 level = ((__raw_readl(rng_base + RNGA_STATUS) &
70 RNGA_STATUS_LEVEL_MASK) >> 8);
71
72 return level > 0 ? 1 : 0;
73}
74
75static int mxc_rnga_data_read(struct hwrng *rng, u32 * data)
76{
77 int err;
78 u32 ctrl;
79 void __iomem *rng_base = (void __iomem *)rng->priv;
80
81
82 *data = __raw_readl(rng_base + RNGA_OUTPUT_FIFO);
83
84
85 err = __raw_readl(rng_base + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;
86
87
88 if (err) {
89 dev_dbg(&rng_dev->dev, "Error while reading random number!\n");
90 ctrl = __raw_readl(rng_base + RNGA_CONTROL);
91 __raw_writel(ctrl | RNGA_CONTROL_CLEAR_INT,
92 rng_base + RNGA_CONTROL);
93 return 0;
94 } else
95 return 4;
96}
97
98static int mxc_rnga_init(struct hwrng *rng)
99{
100 u32 ctrl, osc;
101 void __iomem *rng_base = (void __iomem *)rng->priv;
102
103
104 ctrl = __raw_readl(rng_base + RNGA_CONTROL);
105 __raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, rng_base + RNGA_CONTROL);
106
107
108 osc = __raw_readl(rng_base + RNGA_STATUS);
109 if (osc & RNGA_STATUS_OSC_DEAD) {
110 dev_err(&rng_dev->dev, "RNGA Oscillator is dead!\n");
111 return -ENODEV;
112 }
113
114
115 ctrl = __raw_readl(rng_base + RNGA_CONTROL);
116 __raw_writel(ctrl | RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
117
118 return 0;
119}
120
121static void mxc_rnga_cleanup(struct hwrng *rng)
122{
123 u32 ctrl;
124 void __iomem *rng_base = (void __iomem *)rng->priv;
125
126 ctrl = __raw_readl(rng_base + RNGA_CONTROL);
127
128
129 __raw_writel(ctrl & ~RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
130}
131
132static struct hwrng mxc_rnga = {
133 .name = "mxc-rnga",
134 .init = mxc_rnga_init,
135 .cleanup = mxc_rnga_cleanup,
136 .data_present = mxc_rnga_data_present,
137 .data_read = mxc_rnga_data_read
138};
139
140static int __init mxc_rnga_probe(struct platform_device *pdev)
141{
142 int err = -ENODEV;
143 struct clk *clk;
144 struct resource *res, *mem;
145 void __iomem *rng_base = NULL;
146
147 if (rng_dev)
148 return -EBUSY;
149
150 clk = clk_get(&pdev->dev, "rng");
151 if (IS_ERR(clk)) {
152 dev_err(&pdev->dev, "Could not get rng_clk!\n");
153 err = PTR_ERR(clk);
154 goto out;
155 }
156
157 clk_enable(clk);
158
159 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
160 if (!res) {
161 err = -ENOENT;
162 goto err_region;
163 }
164
165 mem = request_mem_region(res->start, resource_size(res), pdev->name);
166 if (mem == NULL) {
167 err = -EBUSY;
168 goto err_region;
169 }
170
171 rng_base = ioremap(res->start, resource_size(res));
172 if (!rng_base) {
173 err = -ENOMEM;
174 goto err_ioremap;
175 }
176
177 mxc_rnga.priv = (unsigned long)rng_base;
178
179 err = hwrng_register(&mxc_rnga);
180 if (err) {
181 dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
182 goto err_register;
183 }
184
185 rng_dev = pdev;
186
187 dev_info(&pdev->dev, "MXC RNGA Registered.\n");
188
189 return 0;
190
191err_register:
192 iounmap(rng_base);
193 rng_base = NULL;
194
195err_ioremap:
196 release_mem_region(res->start, resource_size(res));
197
198err_region:
199 clk_disable(clk);
200 clk_put(clk);
201
202out:
203 return err;
204}
205
206static int __exit mxc_rnga_remove(struct platform_device *pdev)
207{
208 struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
209 void __iomem *rng_base = (void __iomem *)mxc_rnga.priv;
210 struct clk *clk = clk_get(&pdev->dev, "rng");
211
212 hwrng_unregister(&mxc_rnga);
213
214 iounmap(rng_base);
215
216 release_mem_region(res->start, resource_size(res));
217
218 clk_disable(clk);
219 clk_put(clk);
220
221 return 0;
222}
223
224static struct platform_driver mxc_rnga_driver = {
225 .driver = {
226 .name = "mxc_rnga",
227 .owner = THIS_MODULE,
228 },
229 .remove = __exit_p(mxc_rnga_remove),
230};
231
232static int __init mod_init(void)
233{
234 return platform_driver_probe(&mxc_rnga_driver, mxc_rnga_probe);
235}
236
237static void __exit mod_exit(void)
238{
239 platform_driver_unregister(&mxc_rnga_driver);
240}
241
242module_init(mod_init);
243module_exit(mod_exit);
244
245MODULE_AUTHOR("Freescale Semiconductor, Inc.");
246MODULE_DESCRIPTION("H/W RNGA driver for i.MX");
247MODULE_LICENSE("GPL");
248
