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authorAlessandro Rubini <rubini@unipv.it>2009-12-19 06:45:43 -0500
committerHerbert Xu <herbert@gondor.apana.org.au>2009-12-19 06:45:43 -0500
commitbc85b25e5de17d714e8001cb3dc0feb66eac2750 (patch)
tree279eb8002a8ae7dd137c6e5433074d0bf325ca88
parent55639353a0035052d9ea6cfe4dde0ac7fcbb2c9f (diff)
hwrng: nomadik - Add hardware RNG driver
The hardware random number generator by ST is used in both the Nomadik 8815 SoC and the U8500. It returns 16 bits every 400ns with automatic delay if a read is issued too early. It depends on PLAT_NOMADIK. Signed-off-by: Alessandro Rubini <rubini@unipv.it> Acked-by: Andrea Gallo <andrea.gallo@stericsson.com> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
-rw-r--r--drivers/char/hw_random/Kconfig12
-rw-r--r--drivers/char/hw_random/Makefile1
-rw-r--r--drivers/char/hw_random/nomadik-rng.c103
3 files changed, 116 insertions, 0 deletions
diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 87060266ef91..6ea1014697d1 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -186,3 +186,15 @@ config HW_RANDOM_MXC_RNGA
186 module will be called mxc-rnga. 186 module will be called mxc-rnga.
187 187
188 If unsure, say Y. 188 If unsure, say Y.
189
190config HW_RANDOM_NOMADIK
191 tristate "ST-Ericsson Nomadik Random Number Generator support"
192 depends on HW_RANDOM && PLAT_NOMADIK
193 ---help---
194 This driver provides kernel-side support for the Random Number
195 Generator hardware found on ST-Ericsson SoCs (8815 and 8500).
196
197 To compile this driver as a module, choose M here: the
198 module will be called nomadik-rng.
199
200 If unsure, say Y.
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index 5eeb1303f0d0..4273308aa1e3 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -18,3 +18,4 @@ obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o
18obj-$(CONFIG_HW_RANDOM_TX4939) += tx4939-rng.o 18obj-$(CONFIG_HW_RANDOM_TX4939) += tx4939-rng.o
19obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o 19obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o
20obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o 20obj-$(CONFIG_HW_RANDOM_OCTEON) += octeon-rng.o
21obj-$(CONFIG_HW_RANDOM_NOMADIK) += nomadik-rng.o
diff --git a/drivers/char/hw_random/nomadik-rng.c b/drivers/char/hw_random/nomadik-rng.c
new file mode 100644
index 000000000000..a8b4c4010144
--- /dev/null
+++ b/drivers/char/hw_random/nomadik-rng.c
@@ -0,0 +1,103 @@
1/*
2 * Nomadik RNG support
3 * Copyright 2009 Alessandro Rubini
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License as published by
7 * the Free Software Foundation; either version 2 of the License, or
8 * (at your option) any later version.
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/init.h>
14#include <linux/device.h>
15#include <linux/amba/bus.h>
16#include <linux/hw_random.h>
17#include <linux/io.h>
18
19static int nmk_rng_read(struct hwrng *rng, void *data, size_t max, bool wait)
20{
21 void __iomem *base = (void __iomem *)rng->priv;
22
23 /*
24 * The register is 32 bits and gives 16 random bits (low half).
25 * A subsequent read will delay the core for 400ns, so we just read
26 * once and accept the very unlikely very small delay, even if wait==0.
27 */
28 *(u16 *)data = __raw_readl(base + 8) & 0xffff;
29 return 2;
30}
31
32/* we have at most one RNG per machine, granted */
33static struct hwrng nmk_rng = {
34 .name = "nomadik",
35 .read = nmk_rng_read,
36};
37
38static int nmk_rng_probe(struct amba_device *dev, struct amba_id *id)
39{
40 void __iomem *base;
41 int ret;
42
43 ret = amba_request_regions(dev, dev->dev.init_name);
44 if (ret)
45 return ret;
46 ret = -ENOMEM;
47 base = ioremap(dev->res.start, resource_size(&dev->res));
48 if (!base)
49 goto out_release;
50 nmk_rng.priv = (unsigned long)base;
51 ret = hwrng_register(&nmk_rng);
52 if (ret)
53 goto out_unmap;
54 return 0;
55
56out_unmap:
57 iounmap(base);
58out_release:
59 amba_release_regions(dev);
60 return ret;
61}
62
63static int nmk_rng_remove(struct amba_device *dev)
64{
65 void __iomem *base = (void __iomem *)nmk_rng.priv;
66 hwrng_unregister(&nmk_rng);
67 iounmap(base);
68 amba_release_regions(dev);
69 return 0;
70}
71
72static struct amba_id nmk_rng_ids[] = {
73 {
74 .id = 0x000805e1,
75 .mask = 0x000fffff, /* top bits are rev and cfg: accept all */
76 },
77 {0, 0},
78};
79
80static struct amba_driver nmk_rng_driver = {
81 .drv = {
82 .owner = THIS_MODULE,
83 .name = "rng",
84 },
85 .probe = nmk_rng_probe,
86 .remove = nmk_rng_remove,
87 .id_table = nmk_rng_ids,
88};
89
90static int __init nmk_rng_init(void)
91{
92 return amba_driver_register(&nmk_rng_driver);
93}
94
95static void __devexit nmk_rng_exit(void)
96{
97 amba_driver_unregister(&nmk_rng_driver);
98}
99
100module_init(nmk_rng_init);
101module_exit(nmk_rng_exit);
102
103MODULE_LICENSE("GPL");