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Commit 1907da78 authored by Alexander Clouter's avatar Alexander Clouter Committed by Herbert Xu
Browse files

hwrng: timeriomem - update to support more than one device 



timeriomem_rng only supports a single device instance.  This patch
enables multiple timeriomem_rng devices to coexist as well as adds
some additional error checking.

Signed-off-by: default avatarAlexander Clouter <alex@digriz.org.uk>
Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 57ae1b05

drivers/char/hw_random/timeriomem-rng.c

+116 −54
Original line number Diff line number Diff line
@@ -25,117 +25,179 @@ 
#include <linux/platform_device.h>

#include <linux/hw_random.h>

#include <linux/io.h>

#include <linux/slab.h>

#include <linux/timeriomem-rng.h>

#include <linux/jiffies.h>

#include <linux/sched.h>

#include <linux/timer.h>

#include <linux/completion.h>



static struct timeriomem_rng_data *timeriomem_rng_data;

struct timeriomem_rng_private_data {

	void __iomem		*io_base;

	unsigned int		expires;

	unsigned int		period;

	unsigned int		present:1;



static void timeriomem_rng_trigger(unsigned long);

static DEFINE_TIMER(timeriomem_rng_timer, timeriomem_rng_trigger, 0, 0);

	struct timer_list	timer;

	struct completion	completion;



	struct hwrng		timeriomem_rng_ops;

};



#define to_rng_priv(rng) \

		((struct timeriomem_rng_private_data *)rng->priv)



/*

 * have data return 1, however return 0 if we have nothing

 */

static int timeriomem_rng_data_present(struct hwrng *rng, int wait)

{

	if (rng->priv == 0)

		return 1;

	struct timeriomem_rng_private_data *priv = to_rng_priv(rng);



	if (!wait || timeriomem_rng_data->present)

		return timeriomem_rng_data->present;

	if (!wait || priv->present)

		return priv->present;



	wait_for_completion(&timeriomem_rng_data->completion);

	wait_for_completion(&priv->completion);



	return 1;

}



static int timeriomem_rng_data_read(struct hwrng *rng, u32 *data)

{

	struct timeriomem_rng_private_data *priv = to_rng_priv(rng);

	unsigned long cur;

	s32 delay;



	*data = readl(timeriomem_rng_data->address);

	*data = readl(priv->io_base);



	if (rng->priv != 0) {

	cur = jiffies;



		delay = cur - timeriomem_rng_timer.expires;

		delay = rng->priv - (delay % rng->priv);

	delay = cur - priv->expires;

	delay = priv->period - (delay % priv->period);



		timeriomem_rng_timer.expires = cur + delay;

		timeriomem_rng_data->present = 0;

	priv->expires = cur + delay;

	priv->present = 0;



		init_completion(&timeriomem_rng_data->completion);

		add_timer(&timeriomem_rng_timer);

	}

	INIT_COMPLETION(priv->completion);

	mod_timer(&priv->timer, priv->expires);



	return 4;

}



static void timeriomem_rng_trigger(unsigned long dummy)

static void timeriomem_rng_trigger(unsigned long data)

{

	timeriomem_rng_data->present = 1;

	complete(&timeriomem_rng_data->completion);

}

	struct timeriomem_rng_private_data *priv

			= (struct timeriomem_rng_private_data *)data;



static struct hwrng timeriomem_rng_ops = {

	.name		= "timeriomem",

	.data_present	= timeriomem_rng_data_present,

	.data_read	= timeriomem_rng_data_read,

	.priv		= 0,

};

	priv->present = 1;

	complete(&priv->completion);

}



static int timeriomem_rng_probe(struct platform_device *pdev)

{

	struct timeriomem_rng_data *pdata = pdev->dev.platform_data;

	struct timeriomem_rng_private_data *priv;

	struct resource *res;

	int ret;

	int err = 0;

	int period;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!pdata) {

		dev_err(&pdev->dev, "timeriomem_rng_data is missing\n");

		return -EINVAL;

	}



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	if (!res)

		return -ENOENT;

		return -ENXIO;



	timeriomem_rng_data = pdev->dev.platform_data;

	if (res->start % 4 != 0 || resource_size(res) != 4) {

		dev_err(&pdev->dev,

			"address must be four bytes wide and aligned\n");

		return -EINVAL;

	}



	timeriomem_rng_data->address = ioremap(res->start, resource_size(res));

	if (!timeriomem_rng_data->address)

		return -EIO;

	/* Allocate memory for the device structure (and zero it) */

	priv = kzalloc(sizeof(struct timeriomem_rng_private_data), GFP_KERNEL);

	if (!priv) {

		dev_err(&pdev->dev, "failed to allocate device structure.\n");

		return -ENOMEM;

	}



	platform_set_drvdata(pdev, priv);



	if (timeriomem_rng_data->period != 0

		&& usecs_to_jiffies(timeriomem_rng_data->period) > 0) {

		timeriomem_rng_timer.expires = jiffies;

	period = pdata->period;



		timeriomem_rng_ops.priv = usecs_to_jiffies(

						timeriomem_rng_data->period);

	priv->period = usecs_to_jiffies(period);

	if (priv->period < 1) {

		dev_err(&pdev->dev, "period is less than one jiffy\n");

		err = -EINVAL;

		goto out_free;

	}

	timeriomem_rng_data->present = 1;



	ret = hwrng_register(&timeriomem_rng_ops);

	if (ret)

		goto failed;

	priv->expires	= jiffies;

	priv->present	= 1;



	dev_info(&pdev->dev, "32bits from 0x%p @ %dus\n",

			timeriomem_rng_data->address,

			timeriomem_rng_data->period);

	init_completion(&priv->completion);

	complete(&priv->completion);



	return 0;

	setup_timer(&priv->timer, timeriomem_rng_trigger, (unsigned long)priv);



	priv->timeriomem_rng_ops.name		= dev_name(&pdev->dev);

	priv->timeriomem_rng_ops.data_present	= timeriomem_rng_data_present;

	priv->timeriomem_rng_ops.data_read	= timeriomem_rng_data_read;

	priv->timeriomem_rng_ops.priv		= (unsigned long)priv;



	if (!request_mem_region(res->start, resource_size(res),

				dev_name(&pdev->dev))) {

		dev_err(&pdev->dev, "request_mem_region failed\n");

		err = -EBUSY;

		goto out_timer;

	}



failed:

	priv->io_base = ioremap(res->start, resource_size(res));

	if (priv->io_base == NULL) {

		dev_err(&pdev->dev, "ioremap failed\n");

		err = -EIO;

		goto out_release_io;

	}



	err = hwrng_register(&priv->timeriomem_rng_ops);

	if (err) {

		dev_err(&pdev->dev, "problem registering\n");

	iounmap(timeriomem_rng_data->address);

		goto out;

	}



	return ret;

	dev_info(&pdev->dev, "32bits from 0x%p @ %dus\n",

			priv->io_base, period);



	return 0;



out:

	iounmap(priv->io_base);

out_release_io:

	release_mem_region(res->start, resource_size(res));

out_timer:

	del_timer_sync(&priv->timer);

out_free:

	platform_set_drvdata(pdev, NULL);

	kfree(priv);

	return err;

}



static int timeriomem_rng_remove(struct platform_device *pdev)

{

	del_timer_sync(&timeriomem_rng_timer);

	hwrng_unregister(&timeriomem_rng_ops);

	struct timeriomem_rng_private_data *priv = platform_get_drvdata(pdev);

	struct resource *res;



	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);



	hwrng_unregister(&priv->timeriomem_rng_ops);



	iounmap(timeriomem_rng_data->address);

	del_timer_sync(&priv->timer);

	iounmap(priv->io_base);

	release_mem_region(res->start, resource_size(res));

	platform_set_drvdata(pdev, NULL);

	kfree(priv);



	return 0;

}

include/linux/timeriomem-rng.h

+0 −5
Original line number Diff line number Diff line
@@ -8,12 +8,7 @@ 
 * published by the Free Software Foundation.

 */



#include <linux/completion.h>



struct timeriomem_rng_data {

	struct completion	completion;

	unsigned int		present:1;



	void __iomem		*address;



	/* measures in usecs */