hwrng: timeriomem - Migrate to new API

Preserves the existing behavior of only returning 32-bits per call.

Signed-off-by: Rick Altherr <raltherr@google.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/char/hw_random/timeriomem-rng.c b/drivers/char/hw_random/timeriomem-rng.c
index cf37db2..1757445 100644 (file)
--- a/drivers/char/hw_random/timeriomem-rng.c
+++ b/drivers/char/hw_random/timeriomem-rng.c
@@ -20,18 +20,16 @@
  * TODO: add support for reading sizes other than 32bits and masking
  */
 
-#include <linux/module.h>
-#include <linux/kernel.h>
-#include <linux/platform_device.h>
-#include <linux/of.h>
+#include <linux/completion.h>
 #include <linux/hw_random.h>
 #include <linux/io.h>
+#include <linux/jiffies.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.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>
 
 struct timeriomem_rng_private_data {
        void __iomem            *io_base;
@@ -45,32 +43,36 @@ struct timeriomem_rng_private_data {
        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)
+static int timeriomem_rng_read(struct hwrng *hwrng, void *data,
+                               size_t max, bool wait)
 {
-       struct timeriomem_rng_private_data *priv = to_rng_priv(rng);
+       struct timeriomem_rng_private_data *priv =
+               container_of(hwrng, struct timeriomem_rng_private_data,
+                               timeriomem_rng_ops);
+       unsigned long cur;
+       s32 delay;
 
-       if (!wait || priv->present)
-               return priv->present;
+       /* The RNG provides 32-bit per read.  Ensure there is enough space. */
+       if (max < sizeof(u32))
+               return 0;
 
-       wait_for_completion(&priv->completion);
+       /*
+        * There may not have been enough time for new data to be generated
+        * since the last request.  If the caller doesn't want to wait, let them
+        * bail out.  Otherwise, wait for the completion.  If the new data has
+        * already been generated, the completion should already be available.
+        */
+       if (!wait && !priv->present)
+               return 0;
 
-       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;
+       wait_for_completion(&priv->completion);
 
-       *data = readl(priv->io_base);
+       *(u32 *)data = readl(priv->io_base);
 
+       /*
+        * Block any new callers until the RNG has had time to generate new
+        * data.
+        */
        cur = jiffies;
 
        delay = cur - priv->expires;
@@ -154,9 +156,7 @@ static int timeriomem_rng_probe(struct platform_device *pdev)
        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;
+       priv->timeriomem_rng_ops.read           = timeriomem_rng_read;
 
        priv->io_base = devm_ioremap_resource(&pdev->dev, res);
        if (IS_ERR(priv->io_base)) {