Commit 9dc33705 authored May 10, 2014 by Thierry Escande Committed by Samuel Ortiz May 26, 2014

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>

parent 00e625df

net/nfc/digital_core.c

+4 −2

Original line number	Diff line number	Diff line
		@@ -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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