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>

diff --git a/drivers/char/hw_random/Kconfig b/drivers/char/hw_random/Kconfig
index 5f3acd8..7cda04b 100644 (file)
--- 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 c41fa19..c8b7300 100644 (file)
--- 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 (file)
index 0000000..fa6040b
--- /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");