NFC: Modified hci_transceive to become an asynchronous operation
This enables the completion callback to be called from a different
context, preventing a possible deadlock if the callback resulted in the
invocation of a nested call to the currently locked nfc_dev.
This is also more in line with the im_transceive nfc_ops for NFC Core or
NCI drivers which already behave asynchronously.
Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/nfc/pn544_hci.c b/drivers/nfc/pn544_hci.c
index d90aecf..a176d1f7 100644
--- a/drivers/nfc/pn544_hci.c
+++ b/drivers/nfc/pn544_hci.c
@@ -148,6 +148,9 @@
* < 0 if hardware error occured (e.g. i2c err)
* and prevents normal operation.
*/
+ int async_cb_type;
+ data_exchange_cb_t async_cb;
+ void *async_cb_context;
};
static void pn544_hci_platform_init(struct pn544_hci_info *info)
@@ -731,6 +734,26 @@
return r;
}
+#define PN544_CB_TYPE_READER_F 1
+
+static void pn544_hci_data_exchange_cb(void *context, struct sk_buff *skb,
+ int err)
+{
+ struct pn544_hci_info *info = context;
+
+ switch (info->async_cb_type) {
+ case PN544_CB_TYPE_READER_F:
+ if (err == 0)
+ skb_pull(skb, 1);
+ info->async_cb(info->async_cb_context, skb, err);
+ break;
+ default:
+ if (err == 0)
+ kfree_skb(skb);
+ break;
+ }
+}
+
#define MIFARE_CMD_AUTH_KEY_A 0x60
#define MIFARE_CMD_AUTH_KEY_B 0x61
#define MIFARE_CMD_HEADER 2
@@ -744,11 +767,11 @@
*/
static int pn544_hci_data_exchange(struct nfc_shdlc *shdlc,
struct nfc_target *target,
- struct sk_buff *skb,
- struct sk_buff **res_skb)
+ struct sk_buff *skb, data_exchange_cb_t cb,
+ void *cb_context)
{
+ struct pn544_hci_info *info = nfc_shdlc_get_clientdata(shdlc);
struct nfc_hci_dev *hdev = nfc_shdlc_get_hci_dev(shdlc);
- int r;
pr_info(DRIVER_DESC ": %s for gate=%d\n", __func__,
target->hci_reader_gate);
@@ -773,25 +796,29 @@
memcpy(data, uid, MIFARE_UID_LEN);
}
- return nfc_hci_send_cmd(hdev, target->hci_reader_gate,
- PN544_MIFARE_CMD,
- skb->data, skb->len, res_skb);
+ return nfc_hci_send_cmd_async(hdev,
+ target->hci_reader_gate,
+ PN544_MIFARE_CMD,
+ skb->data, skb->len,
+ cb, cb_context);
} else
return 1;
case PN544_RF_READER_F_GATE:
*skb_push(skb, 1) = 0;
*skb_push(skb, 1) = 0;
- r = nfc_hci_send_cmd(hdev, target->hci_reader_gate,
- PN544_FELICA_RAW,
- skb->data, skb->len, res_skb);
- if (r == 0)
- skb_pull(*res_skb, 1);
- return r;
+ info->async_cb_type = PN544_CB_TYPE_READER_F;
+ info->async_cb = cb;
+ info->async_cb_context = cb_context;
+
+ return nfc_hci_send_cmd_async(hdev, target->hci_reader_gate,
+ PN544_FELICA_RAW, skb->data,
+ skb->len,
+ pn544_hci_data_exchange_cb, info);
case PN544_RF_READER_JEWEL_GATE:
- return nfc_hci_send_cmd(hdev, target->hci_reader_gate,
- PN544_JEWEL_RAW_CMD,
- skb->data, skb->len, res_skb);
+ return nfc_hci_send_cmd_async(hdev, target->hci_reader_gate,
+ PN544_JEWEL_RAW_CMD, skb->data,
+ skb->len, cb, cb_context);
default:
return 1;
}