hwrng: amd - manage resource allocation

As amd driver doesn't bind to PCI device, we'd better manage reource
allocation on our own to disallow (possible) conflicts.

Signed-off-by: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Acked-by: Matt Mackall <mpm@selenic.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

1 files changed, 9 insertions, 0 deletions

diff --git a/drivers/char/hw_random/amd-rng.c b/drivers/char/hw_random/amd-rng.c
index 0d8c5788b8e4..c6af038682f1 100644
--- a/drivers/char/hw_random/amd-rng.c
+++ b/drivers/char/hw_random/amd-rng.c
@@ -133,6 +133,12 @@ found:
         pmbase &= 0x0000FF00;
         if (pmbase == 0)
                 goto out;
+        if (!request_region(pmbase + 0xF0, 8, "AMD HWRNG")) {
+                dev_err(&pdev->dev, "AMD HWRNG region 0x%x already in use!\n",
+                        pmbase + 0xF0);
+                err = -EBUSY;
+                goto out;
+        }
         amd_rng.priv = (unsigned long)pmbase;
         amd_pdev = pdev;
 
@@ -141,6 +147,7 @@ found:
         if (err) {
                 printk(KERN_ERR PFX "RNG registering failed (%d)\n",
                        err);
+                release_region(pmbase + 0xF0, 8);
                 goto out;
         }
 out:
@@ -149,6 +156,8 @@ out:
 
 static void __exit mod_exit(void)
 {
+        u32 pmbase = (unsigned long)amd_rng.priv;
+        release_region(pmbase + 0xF0, 8);
         hwrng_unregister(&amd_rng);
 }