diff options
author | Atsushi Nemoto <anemo@mba.ocn.ne.jp> | 2009-06-02 10:54:21 -0400 |
---|---|---|
committer | Ralf Baechle <ralf@linux-mips.org> | 2009-06-17 06:06:27 -0400 |
commit | 049a947c611a19523eaaf193f698b897a62d0593 (patch) | |
tree | d50ee24ac5cdcd092424d9f8c76a10315b346814 /drivers/char | |
parent | c3b28ae260d99a5364a31210a36a3246bd9647f7 (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/Kconfig | 13 | ||||
-rw-r--r-- | drivers/char/hw_random/Makefile | 1 | ||||
-rw-r--r-- | drivers/char/hw_random/tx4939-rng.c | 184 |
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 | ||
152 | config 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 | |||
152 | config HW_RANDOM_MXC_RNGA | 165 | config 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-$(CONFIG_HW_RANDOM_IXP4XX) += ixp4xx-rng.o | |||
15 | obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o | 15 | obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o |
16 | obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o | 16 | obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o |
17 | obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o | 17 | obj-$(CONFIG_HW_RANDOM_VIRTIO) += virtio-rng.o |
18 | obj-$(CONFIG_HW_RANDOM_TX4939) += tx4939-rng.o | ||
18 | obj-$(CONFIG_HW_RANDOM_MXC_RNGA) += mxc-rnga.o | 19 | obj-$(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 | |||
26 | struct tx4939_rng { | ||
27 | struct hwrng rng; | ||
28 | void __iomem *base; | ||
29 | u64 databuf[3]; | ||
30 | unsigned int data_avail; | ||
31 | }; | ||
32 | |||
33 | static 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 | |||
46 | static void rng_io_end(void) | ||
47 | { | ||
48 | #ifndef CONFIG_64BIT | ||
49 | local_irq_enable(); | ||
50 | #endif | ||
51 | } | ||
52 | |||
53 | static u64 read_rng(void __iomem *base, unsigned int offset) | ||
54 | { | ||
55 | return ____raw_readq(base + offset); | ||
56 | } | ||
57 | |||
58 | static void write_rng(u64 val, void __iomem *base, unsigned int offset) | ||
59 | { | ||
60 | return ____raw_writeq(val, base + offset); | ||
61 | } | ||
62 | |||
63 | static 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 | |||
96 | static 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 | |||
105 | static 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 | |||
153 | static 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 | |||
162 | static struct platform_driver tx4939_rng_driver = { | ||
163 | .driver = { | ||
164 | .name = "tx4939-rng", | ||
165 | .owner = THIS_MODULE, | ||
166 | }, | ||
167 | .remove = tx4939_rng_remove, | ||
168 | }; | ||
169 | |||
170 | static int __init tx4939rng_init(void) | ||
171 | { | ||
172 | return platform_driver_probe(&tx4939_rng_driver, tx4939_rng_probe); | ||
173 | } | ||
174 | |||
175 | static void __exit tx4939rng_exit(void) | ||
176 | { | ||
177 | platform_driver_unregister(&tx4939_rng_driver); | ||
178 | } | ||
179 | |||
180 | module_init(tx4939rng_init); | ||
181 | module_exit(tx4939rng_exit); | ||
182 | |||
183 | MODULE_DESCRIPTION("H/W Random Number Generator (RNG) driver for TX4939"); | ||
184 | MODULE_LICENSE("GPL"); | ||