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hwrng: mxc-rnga - Access data via structure
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In current driver, everytime we need to access the rng clock
,ie to enable or disable it, a call to clk_get is done.

This is not correct and the preferred way is to provide a rng data structure
that could be used for accessing rng resources.

Acked-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
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Fabio Estevam authored and Herbert Xu committed Sep 6, 2012
1 parent a9ccb7b commit 821873a
Showing 1 changed file with 51 additions and 57 deletions.
108 changes: 51 additions & 57 deletions drivers/char/hw_random/mxc-rnga.c
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Original file line number Diff line number Diff line change
Expand Up @@ -59,16 +59,21 @@
#define RNGA_STATUS_LAST_READ_STATUS 0x00000002
#define RNGA_STATUS_SECURITY_VIOLATION 0x00000001

static struct platform_device *rng_dev;
struct mxc_rng {
struct device *dev;
struct hwrng rng;
void __iomem *mem;
struct clk *clk;
};

static int mxc_rnga_data_present(struct hwrng *rng, int wait)
{
void __iomem *rng_base = (void __iomem *)rng->priv;
int i;
struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);

for (i = 0; i < 20; i++) {
/* how many random numbers are in FIFO? [0-16] */
int level = (__raw_readl(rng_base + RNGA_STATUS) &
int level = (__raw_readl(mxc_rng->mem + RNGA_STATUS) &
RNGA_STATUS_LEVEL_MASK) >> 8;
if (level || !wait)
return !!level;
Expand All @@ -81,20 +86,20 @@ static int mxc_rnga_data_read(struct hwrng *rng, u32 * data)
{
int err;
u32 ctrl;
void __iomem *rng_base = (void __iomem *)rng->priv;
struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);

/* retrieve a random number from FIFO */
*data = __raw_readl(rng_base + RNGA_OUTPUT_FIFO);
*data = __raw_readl(mxc_rng->mem + RNGA_OUTPUT_FIFO);

/* some error while reading this random number? */
err = __raw_readl(rng_base + RNGA_STATUS) & RNGA_STATUS_ERROR_INT;
err = __raw_readl(mxc_rng->mem + 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);
dev_dbg(mxc_rng->dev, "Error while reading random number!\n");
ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
__raw_writel(ctrl | RNGA_CONTROL_CLEAR_INT,
rng_base + RNGA_CONTROL);
mxc_rng->mem + RNGA_CONTROL);
return 0;
} else
return 4;
Expand All @@ -103,63 +108,63 @@ static int mxc_rnga_data_read(struct hwrng *rng, u32 * data)
static int mxc_rnga_init(struct hwrng *rng)
{
u32 ctrl, osc;
void __iomem *rng_base = (void __iomem *)rng->priv;
struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);

/* wake up */
ctrl = __raw_readl(rng_base + RNGA_CONTROL);
__raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, rng_base + RNGA_CONTROL);
ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
__raw_writel(ctrl & ~RNGA_CONTROL_SLEEP, mxc_rng->mem + RNGA_CONTROL);

/* verify if oscillator is working */
osc = __raw_readl(rng_base + RNGA_STATUS);
osc = __raw_readl(mxc_rng->mem + RNGA_STATUS);
if (osc & RNGA_STATUS_OSC_DEAD) {
dev_err(&rng_dev->dev, "RNGA Oscillator is dead!\n");
dev_err(mxc_rng->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);
ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);
__raw_writel(ctrl | RNGA_CONTROL_GO, mxc_rng->mem + RNGA_CONTROL);

return 0;
}

static void mxc_rnga_cleanup(struct hwrng *rng)
{
u32 ctrl;
void __iomem *rng_base = (void __iomem *)rng->priv;
struct mxc_rng *mxc_rng = container_of(rng, struct mxc_rng, rng);

ctrl = __raw_readl(rng_base + RNGA_CONTROL);
ctrl = __raw_readl(mxc_rng->mem + RNGA_CONTROL);

/* stop rnga */
__raw_writel(ctrl & ~RNGA_CONTROL_GO, rng_base + RNGA_CONTROL);
__raw_writel(ctrl & ~RNGA_CONTROL_GO, mxc_rng->mem + 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, NULL);
if (IS_ERR(clk)) {
struct mxc_rng *mxc_rng;

mxc_rng = devm_kzalloc(&pdev->dev, sizeof(struct mxc_rng),
GFP_KERNEL);
if (!mxc_rng)
return -ENOMEM;

mxc_rng->dev = &pdev->dev;
mxc_rng->rng.name = "mxc-rnga";
mxc_rng->rng.init = mxc_rnga_init;
mxc_rng->rng.cleanup = mxc_rnga_cleanup,
mxc_rng->rng.data_present = mxc_rnga_data_present,
mxc_rng->rng.data_read = mxc_rnga_data_read,

mxc_rng->clk = devm_clk_get(&pdev->dev, NULL);
if (IS_ERR(mxc_rng->clk)) {
dev_err(&pdev->dev, "Could not get rng_clk!\n");
err = PTR_ERR(clk);
err = PTR_ERR(mxc_rng->clk);
goto out;
}

clk_prepare_enable(clk);
clk_prepare_enable(mxc_rng->clk);

res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!res) {
Expand All @@ -173,36 +178,27 @@ static int __init mxc_rnga_probe(struct platform_device *pdev)
goto err_region;
}

rng_base = ioremap(res->start, resource_size(res));
if (!rng_base) {
mxc_rng->mem = ioremap(res->start, resource_size(res));
if (!mxc_rng->mem) {
err = -ENOMEM;
goto err_ioremap;
}

mxc_rnga.priv = (unsigned long)rng_base;

err = hwrng_register(&mxc_rnga);
err = hwrng_register(&mxc_rng->rng);
if (err) {
dev_err(&pdev->dev, "MXC RNGA registering failed (%d)\n", err);
goto err_register;
goto err_ioremap;
}

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_unprepare(clk);
clk_put(clk);
clk_disable_unprepare(mxc_rng->clk);

out:
return err;
Expand All @@ -211,17 +207,15 @@ static int __init mxc_rnga_probe(struct platform_device *pdev)
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, NULL);
struct mxc_rng *mxc_rng = platform_get_drvdata(pdev);

hwrng_unregister(&mxc_rnga);
hwrng_unregister(&mxc_rng->rng);

iounmap(rng_base);
iounmap(mxc_rng->mem);

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

clk_disable_unprepare(clk);
clk_put(clk);
clk_disable_unprepare(mxc_rng->clk);

return 0;
}
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