/*
- * driver/char/hw_random/omap-rng.c
- *
- * RNG driver for TI OMAP CPU family
+ * omap-rng.c - RNG driver for TI OMAP CPU family
*
* Author: Deepak Saxena <dsaxena@plexity.net>
*
* Mostly based on original driver:
*
* Copyright (C) 2005 Nokia Corporation
- * Author: Juha Yrj��<juha.yrjola@nokia.com>
+ * Author: Juha Yrjölä <juha.yrjola@nokia.com>
*
* This file is licensed under the terms of the GNU General Public
* License version 2. This program is licensed "as is" without any
* warranty of any kind, whether express or implied.
- *
- * TODO:
- *
- * - Make status updated be interrupt driven so we don't poll
- *
*/
#include <linux/module.h>
#include <linux/err.h>
#include <linux/platform_device.h>
#include <linux/hw_random.h>
+#include <linux/delay.h>
#include <asm/io.h>
static struct clk *rng_ick;
static struct platform_device *rng_dev;
-static u32 omap_rng_read_reg(int reg)
+static inline u32 omap_rng_read_reg(int reg)
{
return __raw_readl(rng_base + reg);
}
-static void omap_rng_write_reg(int reg, u32 val)
+static inline void omap_rng_write_reg(int reg, u32 val)
{
__raw_writel(val, rng_base + reg);
}
-/* REVISIT: Does the status bit really work on 16xx? */
-static int omap_rng_data_present(struct hwrng *rng)
+static int omap_rng_data_present(struct hwrng *rng, int wait)
{
- return omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
+ int data, i;
+
+ for (i = 0; i < 20; i++) {
+ data = omap_rng_read_reg(RNG_STAT_REG) ? 0 : 1;
+ if (data || !wait)
+ break;
+ /* RNG produces data fast enough (2+ MBit/sec, even
+ * during "rngtest" loads, that these delays don't
+ * seem to trigger. We *could* use the RNG IRQ, but
+ * that'd be higher overhead ... so why bother?
+ */
+ udelay(10);
+ }
+ return data;
}
static int omap_rng_data_read(struct hwrng *rng, u32 *data)
* A bit ugly, and it will never actually happen but there can
* be only one RNG and this catches any bork
*/
- BUG_ON(rng_dev);
+ if (rng_dev)
+ return -EBUSY;
if (cpu_is_omap24xx()) {
rng_ick = clk_get(NULL, "rng_ick");
return -EBUSY;
dev_set_drvdata(&pdev->dev, mem);
- rng_base = (u32 __iomem *)io_p2v(res->start);
+ rng_base = (u32 __force __iomem *)io_p2v(res->start);
ret = hwrng_register(&omap_rng_ops);
if (ret) {
#endif
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:omap_rng");
static struct platform_driver omap_rng_driver = {
.driver = {