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authorAlan Carvalho de Assis <acassis@gmail.com>2009-04-02 12:38:41 -0300
committerSascha Hauer <s.hauer@pengutronix.de>2009-05-07 16:17:16 +0200
commit45001e92d0249a8c4b9f6c3695215652e8e8493d (patch)
tree5461b1aec6f78fd0524476d2421487329888d6e9 /drivers/char/hw_random/mxc-rnga.c
parent220bbcea278b4fef7ef0a45ce754222f8ed9d134 (diff)
downloadvexpress-lsk-45001e92d0249a8c4b9f6c3695215652e8e8493d.tar.gz
i.MX31: Add hw-random for RNGA
This hw-random driver add support to RNGA hardware found on some i.MX processors. Signed-off-by: Alan Carvalho de Assis <acassis@gmail.com> Acked-by: Matt Mackall <mpm@selenic.com> Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Diffstat (limited to 'drivers/char/hw_random/mxc-rnga.c')
-rw-r--r--drivers/char/hw_random/mxc-rnga.c247
1 files changed, 247 insertions, 0 deletions
diff --git a/drivers/char/hw_random/mxc-rnga.c b/drivers/char/hw_random/mxc-rnga.c
new file mode 100644
index 00000000000..187c6be80f4
--- /dev/null
+++ b/drivers/char/hw_random/mxc-rnga.c
@@ -0,0 +1,247 @@
+/*
+ * RNG driver for Freescale RNGA
+ *
+ * Copyright 2008-2009 Freescale Semiconductor, Inc. All Rights Reserved.
+ * Author: Alan Carvalho de Assis <acassis@gmail.com>
+ */
+
+/*
+ * The code contained herein is licensed under the GNU General Public
+ * License. You may obtain a copy of the GNU General Public License
+ * Version 2 or later at the following locations:
+ *
+ * http://www.opensource.org/licenses/gpl-license.html
+ * http://www.gnu.org/copyleft/gpl.html
+ *
+ * This driver is based on other RNG drivers.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/clk.h>
+#include <linux/err.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/hw_random.h>
+#include <linux/io.h>
+
+/* RNGA Registers */
+#define RNGA_CONTROL 0x00
+#define RNGA_STATUS 0x04
+#define RNGA_ENTROPY 0x08
+#define RNGA_OUTPUT_FIFO 0x0c
+#define RNGA_MODE 0x10
+#define RNGA_VERIFICATION_CONTROL 0x14
+#define RNGA_OSC_CONTROL_COUNTER 0x18
+#define RNGA_OSC1_COUNTER 0x1c
+#define RNGA_OSC2_COUNTER 0x20
+#define RNGA_OSC_COUNTER_STATUS 0x24
+
+/* RNGA Registers Range */
+#define RNG_ADDR_RANGE 0x28
+
+/* RNGA Control Register */
+#define RNGA_CONTROL_SLEEP 0x00000010
+#define RNGA_CONTROL_CLEAR_INT 0x00000008
+#define RNGA_CONTROL_MASK_INTS 0x00000004
+#define RNGA_CONTROL_HIGH_ASSURANCE 0x00000002
+#define RNGA_CONTROL_GO 0x00000001
+
+#define RNGA_STATUS_LEVEL_MASK 0x0000ff00
+
+/* RNGA Status Register */
+#define RNGA_STATUS_OSC_DEAD 0x80000000
+#define RNGA_STATUS_SLEEP 0x00000010
+#define RNGA_STATUS_ERROR_INT 0x00000008
+#define RNGA_STATUS_FIFO_UNDERFLOW 0x00000004
+#define RNGA_STATUS_LAST_READ_STATUS 0x00000002
+#define RNGA_STATUS_SECURITY_VIOLATION 0x00000001
+
+static struct platform_device *rng_dev;
+
+static int mxc_rnga_data_present(struct hwrng *rng)
+{
+ int level;
+ void __iomem *rng_base = (void __iomem *)rng->priv;
+
+ /* how many random numbers is in FIFO? [0-16] */
+ level = ((__raw_readl(rng_base + RNGA_STATUS) &
+ RNGA_STATUS_LEVEL_MASK) >> 8);
+
+ return level > 0 ? 1 : 0;
+}
+
+static int mxc_rnga_data_read(struct hwrng *rng, u32 * data)
+{
+ int err;
+ u32 ctrl;
+ void __iomem *rng_base = (void __iomem *)rng->priv;
+
+ /* retrieve a random number from FIFO */
+ *data = __raw_readl(rng_base + RNGA_OUTPUT_FIFO);
+
+ /* some error while reading this random number? */
+ err = __raw_readl(rng_base + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;
+
+ /* if error: clear error interrupt, but doesn't return random number */
+ if (err) {
+ dev_dbg(&rng_dev->dev, "Error while reading random number!\n");
+ ctrl = __raw_readl(rng_base + RNGA_CONTROL);
+ __raw_writel(ctrl | RNGA_CONTROL_CLEAR_INT,
+ rng_base + RNGA_CONTROL);
+ return 0;
+ } else
+ return 4;
+}
+
+static int mxc_rnga_init(struct hwrng *rng)
+{
+ u32 ctrl, osc;
+ void __iomem *rng_base = (void __iomem *)rng->priv;
+
+ /* wake up */
+ ctrl = __raw_readl(rng_base + RNGA_CONTROL);
+ __raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, rng_base + RNGA_CONTROL);
+
+ /* verify if oscillator is working */
+ osc = __raw_readl(rng_base + RNGA_STATUS);
+ if (osc & RNGA_STATUS_OSC_DEAD) {
+ dev_err(&rng_dev->dev, "RNGA Oscillator is dead!\n");
+ return -ENODEV;
+ }
+
+ /* go running */
+ ctrl = __raw_readl(rng_base + RNGA_CONTROL);
+ __raw_writel(ctrl | RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
+
+ return 0;
+}
+
+static void mxc_rnga_cleanup(struct hwrng *rng)
+{
+ u32 ctrl;
+ void __iomem *rng_base = (void __iomem *)rng->priv;
+
+ ctrl = __raw_readl(rng_base + RNGA_CONTROL);
+
+ /* stop rnga */
+ __raw_writel(ctrl & ~RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
+}
+
+static struct hwrng mxc_rnga = {
+ .name = "mxc-rnga",
+ .init = mxc_rnga_init,
+ .cleanup = mxc_rnga_cleanup,
+ .data_present = mxc_rnga_data_present,
+ .data_read = mxc_rnga_data_read
+};
+
+static int __init mxc_rnga_probe(struct platform_device *pdev)
+{
+ int err = -ENODEV;
+ struct clk *clk;
+ struct resource *res, *mem;
+ void __iomem *rng_base = NULL;
+
+ if (rng_dev)
+ return -EBUSY;
+
+ clk = clk_get(&pdev->dev, "rng");
+ if (IS_ERR(clk)) {
+ dev_err(&pdev->dev, "Could not get rng_clk!\n");
+ err = PTR_ERR(clk);
+ goto out;
+ }
+
+ clk_enable(clk);
+
+ res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ if (!res) {
+ err = -ENOENT;
+ goto err_region;
+ }
+
+ mem = request_mem_region(res->start, resource_size(res), pdev->name);
+ if (mem == NULL) {
+ err = -EBUSY;
+ goto err_region;
+ }
+
+ rng_base = ioremap(res->start, resource_size(res));
+ if (!rng_base) {
+ err = -ENOMEM;
+ goto err_ioremap;
+ }
+
+ mxc_rnga.priv = (unsigned long)rng_base;
+
+ err = hwrng_register(&mxc_rnga);
+ if (err) {
+ dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
+ goto err_register;
+ }
+
+ rng_dev = pdev;
+
+ dev_info(&pdev->dev, "MXC RNGA Registered.\n");
+
+ return 0;
+
+err_register:
+ iounmap(rng_base);
+ rng_base = NULL;
+
+err_ioremap:
+ release_mem_region(res->start, resource_size(res));
+
+err_region:
+ clk_disable(clk);
+ clk_put(clk);
+
+out:
+ return err;
+}
+
+static int __exit mxc_rnga_remove(struct platform_device *pdev)
+{
+ struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+ void __iomem *rng_base = (void __iomem *)mxc_rnga.priv;
+ struct clk *clk = clk_get(&pdev->dev, "rng");
+
+ hwrng_unregister(&mxc_rnga);
+
+ iounmap(rng_base);
+
+ release_mem_region(res->start, resource_size(res));
+
+ clk_disable(clk);
+ clk_put(clk);
+
+ return 0;
+}
+
+static struct platform_driver mxc_rnga_driver = {
+ .driver = {
+ .name = "mxc_rnga",
+ .owner = THIS_MODULE,
+ },
+ .remove = __exit_p(mxc_rnga_remove),
+};
+
+static int __init mod_init(void)
+{
+ return platform_driver_probe(&mxc_rnga_driver, mxc_rnga_probe);
+}
+
+static void __exit mod_exit(void)
+{
+ platform_driver_unregister(&mxc_rnga_driver);
+}
+
+module_init(mod_init);
+module_exit(mod_exit);
+
+MODULE_AUTHOR("Freescale Semiconductor, Inc.");
+MODULE_DESCRIPTION("H/W RNGA driver for i.MX");
+MODULE_LICENSE("GPL");