NFC: digital: Fix RTOX supervisor PDU handling

When the target needs more time to process the received PDU, it sends
Response Timeout Extension (RTOX) PDU.

When the initiator receives a RTOX PDU, it must reply with a RTOX PDU
and extends the current rwt value with the formula:
 rwt_int = rwt * rtox

This patch takes care of the rtox value passed by the target in the RTOX
PDU and extends the timeout for the next response accordingly.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

diff --git a/net/nfc/digital_dep.c b/net/nfc/digital_dep.c
index 6cf2eeb2e865037f094f1a01a113db9626f80e30..f864ce19e13dbc5d7734ca2ff8308047089c2d70 100644 (file)
--- a/net/nfc/digital_dep.c
+++ b/net/nfc/digital_dep.c
@@ -65,6 +65,9 @@
 #define DIGITAL_NFC_DEP_DID_BIT_SET(pfb) ((pfb) & DIGITAL_NFC_DEP_PFB_DID_BIT)
 #define DIGITAL_NFC_DEP_PFB_PNI(pfb)     ((pfb) & 0x03)
 
+#define DIGITAL_NFC_DEP_RTOX_VALUE(data) ((data) & 0x3F)
+#define DIGITAL_NFC_DEP_RTOX_MAX        59
+
 #define DIGITAL_NFC_DEP_PFB_I_PDU          0x00
 #define DIGITAL_NFC_DEP_PFB_ACK_NACK_PDU   0x40
 #define DIGITAL_NFC_DEP_PFB_SUPERVISOR_PDU 0x80
@@ -643,6 +646,11 @@ static int digital_in_send_rtox(struct nfc_digital_dev *ddev,
        struct digital_dep_req_res *dep_req;
        struct sk_buff *skb;
        int rc;
+       u16 rwt_int;
+
+       rwt_int = ddev->dep_rwt * rtox;
+       if (rwt_int > digital_rwt_map[DIGITAL_NFC_DEP_IN_MAX_WT])
+               rwt_int = digital_rwt_map[DIGITAL_NFC_DEP_IN_MAX_WT];
 
        skb = digital_skb_alloc(ddev, 1);
        if (!skb)
@@ -663,7 +671,7 @@ static int digital_in_send_rtox(struct nfc_digital_dev *ddev,
 
        ddev->skb_add_crc(skb);
 
-       rc = digital_in_send_cmd(ddev, skb, ddev->dep_rwt,
+       rc = digital_in_send_cmd(ddev, skb, rwt_int,
                                 digital_in_recv_dep_res, data_exch);
        if (rc)
                kfree_skb(skb);
@@ -697,6 +705,7 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
        u8 pfb;
        uint size;
        int rc;
+       u8 rtox;
 
        if (IS_ERR(resp)) {
                rc = PTR_ERR(resp);
@@ -865,7 +874,20 @@ static void digital_in_recv_dep_res(struct nfc_digital_dev *ddev, void *arg,
                        goto free_resp;
                }
 
-               rc = digital_in_send_rtox(ddev, data_exch, resp->data[0]);
+               if (ddev->atn_count || ddev->nack_count) {
+                       PROTOCOL_ERR("14.12.4.4");
+                       rc = -EIO;
+                       goto error;
+               }
+
+               rtox = DIGITAL_NFC_DEP_RTOX_VALUE(resp->data[0]);
+               if (!rtox || rtox > DIGITAL_NFC_DEP_RTOX_MAX) {
+                       PROTOCOL_ERR("14.8.4.1");
+                       rc = -EIO;
+                       goto error;
+               }
+
+               rc = digital_in_send_rtox(ddev, data_exch, rtox);
                if (rc)
                        goto error;