/*
- * drivers/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>
*
* 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");
mem = request_mem_region(res->start, res->end - res->start + 1,
pdev->name);
- if (mem == NULL)
- return -EBUSY;
+ if (mem == NULL) {
+ ret = -EBUSY;
+ goto err_region;
+ }
dev_set_drvdata(&pdev->dev, mem);
- rng_base = (u32 __iomem *)io_p2v(res->start);
+ rng_base = ioremap(res->start, res->end - res->start + 1);
+ if (!rng_base) {
+ ret = -ENOMEM;
+ goto err_ioremap;
+ }
ret = hwrng_register(&omap_rng_ops);
- if (ret) {
- release_resource(mem);
- rng_base = NULL;
- return ret;
- }
+ if (ret)
+ goto err_register;
dev_info(&pdev->dev, "OMAP Random Number Generator ver. %02x\n",
omap_rng_read_reg(RNG_REV_REG));
rng_dev = pdev;
return 0;
+
+err_register:
+ iounmap(rng_base);
+ rng_base = NULL;
+err_ioremap:
+ release_resource(mem);
+err_region:
+ if (cpu_is_omap24xx()) {
+ clk_disable(rng_ick);
+ clk_put(rng_ick);
+ }
+ return ret;
}
static int __exit omap_rng_remove(struct platform_device *pdev)
omap_rng_write_reg(RNG_MASK_REG, 0x0);
+ iounmap(rng_base);
+
if (cpu_is_omap24xx()) {
clk_disable(rng_ick);
clk_put(rng_ick);
#endif
+/* work with hotplug and coldplug */
+MODULE_ALIAS("platform:omap_rng");
static struct platform_driver omap_rng_driver = {
.driver = {