2 * Copyright (C) 2006-2007 PA Semi, Inc
4 * Maintained by: Olof Johansson <olof@lixom.net>
6 * Driver for the PWRficient onchip rng
8 * This program is free software; you can redistribute it and/or modify
9 * it under the terms of the GNU General Public License version 2 as
10 * published by the Free Software Foundation.
12 * This program is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
15 * GNU General Public License for more details.
17 * You should have received a copy of the GNU General Public License
18 * along with this program; if not, write to the Free Software
19 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
22 #include <linux/module.h>
23 #include <linux/kernel.h>
24 #include <linux/platform_device.h>
25 #include <linux/hw_random.h>
26 #include <linux/delay.h>
27 #include <linux/of_address.h>
28 #include <linux/of_platform.h>
31 #define SDCRNG_CTL_REG 0x00
32 #define SDCRNG_CTL_FVLD_M 0x0000f000
33 #define SDCRNG_CTL_FVLD_S 12
34 #define SDCRNG_CTL_KSZ 0x00000800
35 #define SDCRNG_CTL_RSRC_CRG 0x00000010
36 #define SDCRNG_CTL_RSRC_RRG 0x00000000
37 #define SDCRNG_CTL_CE 0x00000004
38 #define SDCRNG_CTL_RE 0x00000002
39 #define SDCRNG_CTL_DR 0x00000001
40 #define SDCRNG_CTL_SELECT_RRG_RNG (SDCRNG_CTL_RE | SDCRNG_CTL_RSRC_RRG)
41 #define SDCRNG_CTL_SELECT_CRG_RNG (SDCRNG_CTL_CE | SDCRNG_CTL_RSRC_CRG)
42 #define SDCRNG_VAL_REG 0x20
44 #define MODULE_NAME "pasemi_rng"
46 static int pasemi_rng_data_present(struct hwrng
*rng
, int wait
)
48 void __iomem
*rng_regs
= (void __iomem
*)rng
->priv
;
51 for (i
= 0; i
< 20; i
++) {
52 data
= (in_le32(rng_regs
+ SDCRNG_CTL_REG
)
53 & SDCRNG_CTL_FVLD_M
) ? 1 : 0;
61 static int pasemi_rng_data_read(struct hwrng
*rng
, u32
*data
)
63 void __iomem
*rng_regs
= (void __iomem
*)rng
->priv
;
64 *data
= in_le32(rng_regs
+ SDCRNG_VAL_REG
);
68 static int pasemi_rng_init(struct hwrng
*rng
)
70 void __iomem
*rng_regs
= (void __iomem
*)rng
->priv
;
73 ctl
= SDCRNG_CTL_DR
| SDCRNG_CTL_SELECT_RRG_RNG
| SDCRNG_CTL_KSZ
;
74 out_le32(rng_regs
+ SDCRNG_CTL_REG
, ctl
);
75 out_le32(rng_regs
+ SDCRNG_CTL_REG
, ctl
& ~SDCRNG_CTL_DR
);
80 static void pasemi_rng_cleanup(struct hwrng
*rng
)
82 void __iomem
*rng_regs
= (void __iomem
*)rng
->priv
;
85 ctl
= SDCRNG_CTL_RE
| SDCRNG_CTL_CE
;
86 out_le32(rng_regs
+ SDCRNG_CTL_REG
,
87 in_le32(rng_regs
+ SDCRNG_CTL_REG
) & ~ctl
);
90 static struct hwrng pasemi_rng
= {
92 .init
= pasemi_rng_init
,
93 .cleanup
= pasemi_rng_cleanup
,
94 .data_present
= pasemi_rng_data_present
,
95 .data_read
= pasemi_rng_data_read
,
98 static int rng_probe(struct platform_device
*ofdev
)
100 void __iomem
*rng_regs
;
101 struct device_node
*rng_np
= ofdev
->dev
.of_node
;
105 err
= of_address_to_resource(rng_np
, 0, &res
);
109 rng_regs
= ioremap(res
.start
, 0x100);
114 pasemi_rng
.priv
= (unsigned long)rng_regs
;
116 pr_info("Registering PA Semi RNG\n");
118 err
= hwrng_register(&pasemi_rng
);
126 static int rng_remove(struct platform_device
*dev
)
128 void __iomem
*rng_regs
= (void __iomem
*)pasemi_rng
.priv
;
130 hwrng_unregister(&pasemi_rng
);
136 static struct of_device_id rng_match
[] = {
137 { .compatible
= "1682m-rng", },
138 { .compatible
= "pasemi,pwrficient-rng", },
142 static struct platform_driver rng_driver
= {
144 .name
= "pasemi-rng",
145 .of_match_table
= rng_match
,
148 .remove
= rng_remove
,
151 module_platform_driver(rng_driver
);
153 MODULE_LICENSE("GPL");
154 MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
155 MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");