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authorThierry Escande <thierry.escande@linux.intel.com>2014-05-10 13:06:02 +0200
committerSamuel Ortiz <sameo@linux.intel.com>2014-05-26 00:42:02 +0200
commit9dc33705b26aa67a94d8ada0a083557e9815cd0d (patch)
treeb4fc0baca7eb80ad007fc6f437c85894d8854e1f
parent00e625df3ef6c3ce94ed6fc46565b41f55e379f8 (diff)
downloadblackbird-obmc-linux-9dc33705b26aa67a94d8ada0a083557e9815cd0d.tar.gz
blackbird-obmc-linux-9dc33705b26aa67a94d8ada0a083557e9815cd0d.zip
NFC: digital: Randomize poll cycles
This change adds some entropy to polling cycles, choosing the next polling rf technology randomly. This reflects the change done in the pn533 driver, avoiding possible infinite loop for devices that export 2 targets on 2 different modulations. If the first target is not readable, we will stay in an error loop for ever. Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com> Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
-rw-r--r--net/nfc/digital_core.c6
1 files changed, 4 insertions, 2 deletions
diff --git a/net/nfc/digital_core.c b/net/nfc/digital_core.c
index b105cfb00e76..a6ce3c627e4e 100644
--- a/net/nfc/digital_core.c
+++ b/net/nfc/digital_core.c
@@ -386,6 +386,8 @@ int digital_target_found(struct nfc_digital_dev *ddev,
void digital_poll_next_tech(struct nfc_digital_dev *ddev)
{
+ u8 rand_mod;
+
digital_switch_rf(ddev, 0);
mutex_lock(&ddev->poll_lock);
@@ -395,8 +397,8 @@ void digital_poll_next_tech(struct nfc_digital_dev *ddev)
return;
}
- ddev->poll_tech_index = (ddev->poll_tech_index + 1) %
- ddev->poll_tech_count;
+ get_random_bytes(&rand_mod, sizeof(rand_mod));
+ ddev->poll_tech_index = rand_mod % ddev->poll_tech_count;
mutex_unlock(&ddev->poll_lock);
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