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NFC: digital: Add support for NFC DEP Response Waiting Time

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When sending an ATR_REQ, the initiator must wait for the ATR_RES at
least 'RWT(nfcdep,activation) + dRWT(nfcdep)' and no more than
'RWT(nfcdep,activation) + dRWT(nfcdep) + dT(nfcdep,initiator)'. This
gives a timeout value between 1237 ms and 1337 ms. This patch defines
DIGITAL_ATR_RES_RWT to 1337 used for the timeout value of ATR_REQ
command.

For other DEP PDUs, the initiator must wait between 'RWT + dRWT(nfcdep)'
and 'RWT + dRWT(nfcdep) + dT(nfcdep,initiator)' where RWT is given by
the following formula: '(256 * 16 / f(c)) * 2^wt' where wt is the value
of the TO field in the ATR_RES response and is in the range between 0
and 14. This patch declares a mapping table for wt values and gives RWT
max values between 100 ms and 5049 ms.

This patch also defines DIGITAL_ATR_RES_TO_WT, the maximum wt value in
target mode, to 8.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
This commit is contained in:
Thierry Escande
2016-07-08 15:52:45 +02:00
committed by Samuel Ortiz
parent e200f008ac
commit 1a09c56f54
2 changed files with 56 additions and 16 deletions
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1
include/net/nfc/digital.h
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@@ -226,6 +226,7 @@ struct nfc_digital_dev {
u8 curr_rf_tech;
u8 curr_nfc_dep_pni;
u8 did;
u16 dep_rwt;
u8 local_payload_max;
u8 remote_payload_max;