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Subject[PATCH v2 2/2] hw_random: mxc-rnga: Access data via structure
Date
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.

Cc: Theodore Ts'o <tytso@mit.edu>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: <linux-kernel@vger.kernel.org>
Signed-off-by: Fabio Estevam <fabio.estevam@freescale.com>
---
Changes since v1:
- No changes. Newly introduced in this version
drivers/char/hw_random/mxc-rnga.c | 108 +++++++++++++++++-------------------
1 files changed, 51 insertions(+), 57 deletions(-)
diff --git a/drivers/char/hw_random/mxc-rnga.c b/drivers/char/hw_random/mxc-rnga.c
index 62c7efe..f05d857 100644
--- a/drivers/char/hw_random/mxc-rnga.c
+++ b/drivers/char/hw_random/mxc-rnga.c
@@ -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;
@@ -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;
@@ -103,22 +108,22 @@ 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;
}
@@ -126,40 +131,40 @@ static int mxc_rnga_init(struct hwrng *rng)
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) {
@@ -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;
@@ -211,17 +207,15 @@ out:
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;
}
--
1.7.1



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