pasemi: hardware rng driver

Driver for the on-chip hardware random number generator on PA Semi
PA6T-1682M.

Signed-off-by: Egor Martovetsky <egor@pasemi.com>
Signed-off-by: Olof Johansson <olof@lixom.net>
Signed-off-by: Michael Buesch <mb@bu3sch.de>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Kumar Gala <galak@gate.crashing.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

3 files changed, 171 insertions, 0 deletions

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 5f3acd8e64b8..7cda04b33534 100644
--- a/drivers/char/hw_random/Kconfig
+++ b/drivers/char/hw_random/Kconfig
@@ -91,3 +91,17 @@ config HW_RANDOM_OMAP
           module will be called omap-rng.
 
           If unsure, say Y.
+
+config HW_RANDOM_PASEMI
+        tristate "PA Semi HW Random Number Generator support"
+        depends on HW_RANDOM && PPC_PASEMI
+        default HW_RANDOM
+        ---help---
+          This driver provides kernel-side support for the Random Number
+          Generator hardware found on PA6T-1682M processor.
+
+          To compile this driver as a module, choose M here: the
+          module will be called pasemi-rng.
+
+          If unsure, say Y.
+
diff --git a/drivers/char/hw_random/Makefile b/drivers/char/hw_random/Makefile
index c41fa19454e3..c8b7300e2fb1 100644
--- a/drivers/char/hw_random/Makefile
+++ b/drivers/char/hw_random/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_HW_RANDOM_GEODE) += geode-rng.o
 obj-$(CONFIG_HW_RANDOM_VIA) += via-rng.o
 obj-$(CONFIG_HW_RANDOM_IXP4XX) += ixp4xx-rng.o
 obj-$(CONFIG_HW_RANDOM_OMAP) += omap-rng.o
+obj-$(CONFIG_HW_RANDOM_PASEMI) += pasemi-rng.o
diff --git a/drivers/char/hw_random/pasemi-rng.c b/drivers/char/hw_random/pasemi-rng.c
new file mode 100644
index 000000000000..fa6040b6c8f2
--- /dev/null
+++ b/drivers/char/hw_random/pasemi-rng.c
@@ -0,0 +1,156 @@
+/*
+ * Copyright (C) 2006-2007 PA Semi, Inc
+ *
+ * Maintained by: Olof Johansson <olof@lixom.net>
+ *
+ * Driver for the PWRficient onchip rng
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <asm/of_platform.h>
+#include <asm/io.h>
+
+#define SDCRNG_CTL_REG                  0x00
+#define   SDCRNG_CTL_FVLD_M             0x0000f000
+#define   SDCRNG_CTL_FVLD_S             12
+#define   SDCRNG_CTL_KSZ                0x00000800
+#define   SDCRNG_CTL_RSRC_CRG           0x00000010
+#define   SDCRNG_CTL_RSRC_RRG           0x00000000
+#define   SDCRNG_CTL_CE                 0x00000004
+#define   SDCRNG_CTL_RE                 0x00000002
+#define   SDCRNG_CTL_DR                 0x00000001
+#define   SDCRNG_CTL_SELECT_RRG_RNG     (SDCRNG_CTL_RE | SDCRNG_CTL_RSRC_RRG)
+#define   SDCRNG_CTL_SELECT_CRG_RNG     (SDCRNG_CTL_CE | SDCRNG_CTL_RSRC_CRG)
+#define SDCRNG_VAL_REG                  0x20
+
+#define MODULE_NAME "pasemi_rng"
+
+static int pasemi_rng_data_present(struct hwrng *rng)
+{
+        void __iomem *rng_regs = (void __iomem *)rng->priv;
+
+        return (in_le32(rng_regs + SDCRNG_CTL_REG)
+                & SDCRNG_CTL_FVLD_M) ? 1 : 0;
+}
+
+static int pasemi_rng_data_read(struct hwrng *rng, u32 *data)
+{
+        void __iomem *rng_regs = (void __iomem *)rng->priv;
+        *data = in_le32(rng_regs + SDCRNG_VAL_REG);
+        return 4;
+}
+
+static int pasemi_rng_init(struct hwrng *rng)
+{
+        void __iomem *rng_regs = (void __iomem *)rng->priv;
+        u32 ctl;
+
+        ctl = SDCRNG_CTL_DR | SDCRNG_CTL_SELECT_RRG_RNG | SDCRNG_CTL_KSZ;
+        out_le32(rng_regs + SDCRNG_CTL_REG, ctl);
+        out_le32(rng_regs + SDCRNG_CTL_REG, ctl & ~SDCRNG_CTL_DR);
+
+        return 0;
+}
+
+static void pasemi_rng_cleanup(struct hwrng *rng)
+{
+        void __iomem *rng_regs = (void __iomem *)rng->priv;
+        u32 ctl;
+
+        ctl = SDCRNG_CTL_RE | SDCRNG_CTL_CE;
+        out_le32(rng_regs + SDCRNG_CTL_REG,
+                 in_le32(rng_regs + SDCRNG_CTL_REG) & ~ctl);
+}
+
+static struct hwrng pasemi_rng = {
+        .name           = MODULE_NAME,
+        .init           = pasemi_rng_init,
+        .cleanup        = pasemi_rng_cleanup,
+        .data_present   = pasemi_rng_data_present,
+        .data_read      = pasemi_rng_data_read,
+};
+
+static int __devinit rng_probe(struct of_device *ofdev,
+                               const struct of_device_id *match)
+{
+        void __iomem *rng_regs;
+        struct device_node *rng_np = ofdev->node;
+        struct resource res;
+        int err = 0;
+
+        err = of_address_to_resource(rng_np, 0, &res);
+        if (err)
+                return -ENODEV;
+
+        rng_regs = ioremap(res.start, 0x100);
+
+        if (!rng_regs)
+                return -ENOMEM;
+
+        pasemi_rng.priv = (unsigned long)rng_regs;
+
+        printk(KERN_INFO "Registering PA Semi RNG\n");
+
+        err = hwrng_register(&pasemi_rng);
+
+        if (err)
+                iounmap(rng_regs);
+
+        return err;
+}
+
+static int __devexit rng_remove(struct of_device *dev)
+{
+        void __iomem *rng_regs = (void __iomem *)pasemi_rng.priv;
+
+        hwrng_unregister(&pasemi_rng);
+        iounmap(rng_regs);
+
+        return 0;
+}
+
+static struct of_device_id rng_match[] = {
+        {
+                .compatible      = "1682m-rng",
+        },
+        {},
+};
+
+static struct of_platform_driver rng_driver = {
+        .name           = "pasemi-rng",
+        .match_table    = rng_match,
+        .probe          = rng_probe,
+        .remove         = rng_remove,
+};
+
+static int __init rng_init(void)
+{
+        return of_register_platform_driver(&rng_driver);
+}
+module_init(rng_init);
+
+static void __exit rng_exit(void)
+{
+        of_unregister_platform_driver(&rng_driver);
+}
+module_exit(rng_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
+MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");