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authorAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
committerAndré Fabian Silva Delgado <emulatorman@parabola.nu>2015-08-05 17:04:01 -0300
commit57f0f512b273f60d52568b8c6b77e17f5636edc0 (patch)
tree5e910f0e82173f4ef4f51111366a3f1299037a7b /drivers/char/hw_random/pasemi-rng.c
Initial import
Diffstat (limited to 'drivers/char/hw_random/pasemi-rng.c')
-rw-r--r--drivers/char/hw_random/pasemi-rng.c155
1 files changed, 155 insertions, 0 deletions
diff --git a/drivers/char/hw_random/pasemi-rng.c b/drivers/char/hw_random/pasemi-rng.c
new file mode 100644
index 000000000..51cb1d5cc
--- /dev/null
+++ b/drivers/char/hw_random/pasemi-rng.c
@@ -0,0 +1,155 @@
+/*
+ * 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 <linux/delay.h>
+#include <linux/of_address.h>
+#include <linux/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, int wait)
+{
+ void __iomem *rng_regs = (void __iomem *)rng->priv;
+ int data, i;
+
+ for (i = 0; i < 20; i++) {
+ data = (in_le32(rng_regs + SDCRNG_CTL_REG)
+ & SDCRNG_CTL_FVLD_M) ? 1 : 0;
+ if (data || !wait)
+ break;
+ udelay(10);
+ }
+ return data;
+}
+
+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 rng_probe(struct platform_device *ofdev)
+{
+ void __iomem *rng_regs;
+ struct device_node *rng_np = ofdev->dev.of_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;
+
+ pr_info("Registering PA Semi RNG\n");
+
+ err = hwrng_register(&pasemi_rng);
+
+ if (err)
+ iounmap(rng_regs);
+
+ return err;
+}
+
+static int rng_remove(struct platform_device *dev)
+{
+ void __iomem *rng_regs = (void __iomem *)pasemi_rng.priv;
+
+ hwrng_unregister(&pasemi_rng);
+ iounmap(rng_regs);
+
+ return 0;
+}
+
+static const struct of_device_id rng_match[] = {
+ { .compatible = "1682m-rng", },
+ { .compatible = "pasemi,pwrficient-rng", },
+ { },
+};
+
+static struct platform_driver rng_driver = {
+ .driver = {
+ .name = "pasemi-rng",
+ .of_match_table = rng_match,
+ },
+ .probe = rng_probe,
+ .remove = rng_remove,
+};
+
+module_platform_driver(rng_driver);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Egor Martovetsky <egor@pasemi.com>");
+MODULE_DESCRIPTION("H/W RNG driver for PA Semi processor");