aboutsummaryrefslogtreecommitdiffstats
path: root/drivers/char
diff options
context:
space:
mode:
authorAtsushi Nemoto <anemo@mba.ocn.ne.jp>2009-06-02 10:54:21 -0400
committerRalf Baechle <ralf@linux-mips.org>2009-06-17 06:06:27 -0400
commit049a947c611a19523eaaf193f698b897a62d0593 (patch)
treed50ee24ac5cdcd092424d9f8c76a10315b346814 /drivers/char
parentc3b28ae260d99a5364a31210a36a3246bd9647f7 (diff)
MIPS: hwrng: Add TX4939 RNG driver
This patch adds support for the integrated RNG of the TX4939 SoC. Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Ralf Baechle <ralf@linux-mips.org>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/hw_random/Kconfig13
-rw-r--r--drivers/char/hw_random/Makefile1
-rw-r--r--drivers/char/hw_random/tx4939-rng.c184
3 files changed, 198 insertions, 0 deletions
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index f4b3f7293feb..ce66a70184f7 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -149,6 +149,19 @@ config HW_RANDOM_VIRTIO
149 To compile this driver as a module, choose M here: the 149 To compile this driver as a module, choose M here: the
150 module will be called virtio-rng. If unsure, say N. 150 module will be called virtio-rng. If unsure, say N.
151 151
152config HW_RANDOM_TX4939
153 tristate "TX4939 Random Number Generator support"
154 depends on HW_RANDOM && SOC_TX4939
155 default HW_RANDOM
156 ---help---
157 This driver provides kernel-side support for the Random Number
158 Generator hardware found on TX4939 SoC.
159
160 To compile this driver as a module, choose M here: the
161 module will be called tx4939-rng.
162
163 If unsure, say Y.
164
152config HW_RANDOM_MXC_RNGA 165config HW_RANDOM_MXC_RNGA
153 tristate "Freescale i.MX RNGA Random Number Generator" 166 tristate "Freescale i.MX RNGA Random Number Generator"
154 depends on HW_RANDOM && ARCH_HAS_RNGA 167 depends on HW_RANDOM && ARCH_HAS_RNGA
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index fd1ecd2f6731..676828ba8123 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -15,4 +15,5 @@ obj-$(CONFIG_HW_RANDOM_IXP4XX) += ixp4xx-rng.o
15obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o 15obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o
16obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o 16obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o
17obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o 17obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o
18obj-$(CONFIG_HW_RANDOM_TX4939) += tx4939-rng.o
18obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o 19obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o
diff --git a/drivers/char/hw_random/tx4939-rng.c b/drivers/char/hw_random/tx4939-rng.c
new file mode 100644
index 000000000000..544d9085a8e8
--- /dev/null
+++ b/drivers/char/hw_random/tx4939-rng.c
@@ -0,0 +1,184 @@
1/*
2 * RNG driver for TX4939 Random Number Generators (RNG)
3 *
4 * Copyright (C) 2009 Atsushi Nemoto <anemo@mba.ocn.ne.jp>
5 *
6 * This file is subject to the terms and conditions of the GNU General Public
7 * License. See the file "COPYING" in the main directory of this archive
8 * for more details.
9 */
10#include <linux/module.h>
11#include <linux/kernel.h>
12#include <linux/init.h>
13#include <linux/delay.h>
14#include <linux/io.h>
15#include <linux/platform_device.h>
16#include <linux/hw_random.h>
17
18#define TX4939_RNG_RCSR 0x00000000
19#define TX4939_RNG_ROR(n) (0x00000018 + (n) * 8)
20
21#define TX4939_RNG_RCSR_INTE 0x00000008
22#define TX4939_RNG_RCSR_RST 0x00000004
23#define TX4939_RNG_RCSR_FIN 0x00000002
24#define TX4939_RNG_RCSR_ST 0x00000001
25
26struct tx4939_rng {
27 struct hwrng rng;
28 void __iomem *base;
29 u64 databuf[3];
30 unsigned int data_avail;
31};
32
33static void rng_io_start(void)
34{
35#ifndef CONFIG_64BIT
36 /*
37 * readq is reading a 64-bit register using a 64-bit load. On
38 * a 32-bit kernel however interrupts or any other processor
39 * exception would clobber the upper 32-bit of the processor
40 * register so interrupts need to be disabled.
41 */
42 local_irq_disable();
43#endif
44}
45
46static void rng_io_end(void)
47{
48#ifndef CONFIG_64BIT
49 local_irq_enable();
50#endif
51}
52
53static u64 read_rng(void __iomem *base, unsigned int offset)
54{
55 return ____raw_readq(base + offset);
56}
57
58static void write_rng(u64 val, void __iomem *base, unsigned int offset)
59{
60 return ____raw_writeq(val, base + offset);
61}
62
63static int tx4939_rng_data_present(struct hwrng *rng, int wait)
64{
65 struct tx4939_rng *rngdev = container_of(rng, struct tx4939_rng, rng);
66 int i;
67
68 if (rngdev->data_avail)
69 return rngdev->data_avail;
70 for (i = 0; i < 20; i++) {
71 rng_io_start();
72 if (!(read_rng(rngdev->base, TX4939_RNG_RCSR)
73 & TX4939_RNG_RCSR_ST)) {
74 rngdev->databuf[0] =
75 read_rng(rngdev->base, TX4939_RNG_ROR(0));
76 rngdev->databuf[1] =
77 read_rng(rngdev->base, TX4939_RNG_ROR(1));
78 rngdev->databuf[2] =
79 read_rng(rngdev->base, TX4939_RNG_ROR(2));
80 rngdev->data_avail =
81 sizeof(rngdev->databuf) / sizeof(u32);
82 /* Start RNG */
83 write_rng(TX4939_RNG_RCSR_ST,
84 rngdev->base, TX4939_RNG_RCSR);
85 wait = 0;
86 }
87 rng_io_end();
88 if (!wait)
89 break;
90 /* 90 bus clock cycles by default for generation */
91 ndelay(90 * 5);
92 }
93 return rngdev->data_avail;
94}
95
96static int tx4939_rng_data_read(struct hwrng *rng, u32 *buffer)
97{
98 struct tx4939_rng *rngdev = container_of(rng, struct tx4939_rng, rng);
99
100 rngdev->data_avail--;
101 *buffer = *((u32 *)&rngdev->databuf + rngdev->data_avail);
102 return sizeof(u32);
103}
104
105static int __init tx4939_rng_probe(struct platform_device *dev)
106{
107 struct tx4939_rng *rngdev;
108 struct resource *r;
109 int i;
110
111 r = platform_get_resource(dev, IORESOURCE_MEM, 0);
112 if (!r)
113 return -EBUSY;
114 rngdev = devm_kzalloc(&dev->dev, sizeof(*rngdev), GFP_KERNEL);
115 if (!rngdev)
116 return -ENOMEM;
117 if (!devm_request_mem_region(&dev->dev, r->start, resource_size(r),
118 dev_name(&dev->dev)))
119 return -EBUSY;
120 rngdev->base = devm_ioremap(&dev->dev, r->start, resource_size(r));
121 if (!rngdev->base)
122 return -EBUSY;
123
124 rngdev->rng.name = dev_name(&dev->dev);
125 rngdev->rng.data_present = tx4939_rng_data_present;
126 rngdev->rng.data_read = tx4939_rng_data_read;
127
128 rng_io_start();
129 /* Reset RNG */
130 write_rng(TX4939_RNG_RCSR_RST, rngdev->base, TX4939_RNG_RCSR);
131 write_rng(0, rngdev->base, TX4939_RNG_RCSR);
132 /* Start RNG */
133 write_rng(TX4939_RNG_RCSR_ST, rngdev->base, TX4939_RNG_RCSR);
134 rng_io_end();
135 /*
136 * Drop first two results. From the datasheet:
137 * The quality of the random numbers generated immediately
138 * after reset can be insufficient. Therefore, do not use
139 * random numbers obtained from the first and second
140 * generations; use the ones from the third or subsequent
141 * generation.
142 */
143 for (i = 0; i < 2; i++) {
144 rngdev->data_avail = 0;
145 if (!tx4939_rng_data_present(&rngdev->rng, 1))
146 return -EIO;
147 }
148
149 platform_set_drvdata(dev, rngdev);
150 return hwrng_register(&rngdev->rng);
151}
152
153static int __exit tx4939_rng_remove(struct platform_device *dev)
154{
155 struct tx4939_rng *rngdev = platform_get_drvdata(dev);
156
157 hwrng_unregister(&rngdev->rng);
158 platform_set_drvdata(dev, NULL);
159 return 0;
160}
161
162static struct platform_driver tx4939_rng_driver = {
163 .driver = {
164 .name = "tx4939-rng",
165 .owner = THIS_MODULE,
166 },
167 .remove = tx4939_rng_remove,
168};
169
170static int __init tx4939rng_init(void)
171{
172 return platform_driver_probe(&tx4939_rng_driver, tx4939_rng_probe);
173}
174
175static void __exit tx4939rng_exit(void)
176{
177 platform_driver_unregister(&tx4939_rng_driver);
178}
179
180module_init(tx4939rng_init);
181module_exit(tx4939rng_exit);
182
183MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver for TX4939");
184MODULE_LICENSE("GPL");