NFC: st21nfcb: Add driver for STMicroelectronics ST21NFCB NFC chip

Add driver for STMicroelectronics ST21NFCB NFC controller.
ST21NFCB is using NCI protocol and a proprietary low level transport
protocol called NDLC used on top.

NDLC:
The protocol defines 2 types of frame:
- One type carrying NCI data (referred as DATAFRAME frames).
- One type carrying protocol information used for flow control and error
control mechanisms (referred as SUPERVISOR frames).

After each frame transmission to the NFC controller, the device host
SHALL waitfor  an ACK (SUPERVISOR frame) reception before sending a
new frame.
The NFC controller MAY send a frame at anytime to the device host.
The NFC controller MAY send a specific WAIT supervisor frame to indicate
to device host that a NCI data packet has been received but that it could
take significant time before the NFC controller sends an ACK and thus
allows next data reception.

Signed-off-by: Christophe Ricard <christophe-h.ricard@st.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 129 insertions, 0 deletions

diff --git a/drivers/nfc/st21nfcb/st21nfcb.c b/drivers/nfc/st21nfcb/st21nfcb.c
new file mode 100644
index 000000000000..4d95863e3063
--- /dev/null
+++ b/drivers/nfc/st21nfcb/st21nfcb.c
@@ -0,0 +1,129 @@
+/*
+ * NCI based Driver for STMicroelectronics NFC Chip
+ *
+ * Copyright (C) 2014  STMicroelectronics SAS. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/module.h>
+#include <linux/nfc.h>
+#include <net/nfc/nci.h>
+#include <net/nfc/nci_core.h>
+
+#include "st21nfcb.h"
+#include "ndlc.h"
+
+#define DRIVER_DESC "NCI NFC driver for ST21NFCB"
+
+static int st21nfcb_nci_open(struct nci_dev *ndev)
+{
+	struct st21nfcb_nci_info *info = nci_get_drvdata(ndev);
+	int r;
+
+	if (test_and_set_bit(ST21NFCB_NCI_RUNNING, &info->flags))
+		return 0;
+
+	r = ndlc_open(info->ndlc);
+	if (r)
+		clear_bit(ST21NFCB_NCI_RUNNING, &info->flags);
+
+	return r;
+}
+
+static int st21nfcb_nci_close(struct nci_dev *ndev)
+{
+	struct st21nfcb_nci_info *info = nci_get_drvdata(ndev);
+
+	if (!test_and_clear_bit(ST21NFCB_NCI_RUNNING, &info->flags))
+		return 0;
+
+	ndlc_close(info->ndlc);
+
+	return 0;
+}
+
+static int st21nfcb_nci_send(struct nci_dev *ndev, struct sk_buff *skb)
+{
+	struct st21nfcb_nci_info *info = nci_get_drvdata(ndev);
+
+	skb->dev = (void *)ndev;
+
+	if (!test_bit(ST21NFCB_NCI_RUNNING, &info->flags))
+		return -EBUSY;
+
+	return ndlc_send(info->ndlc, skb);
+}
+
+static struct nci_ops st21nfcb_nci_ops = {
+	.open = st21nfcb_nci_open,
+	.close = st21nfcb_nci_close,
+	.send = st21nfcb_nci_send,
+};
+
+int st21nfcb_nci_probe(struct llt_ndlc *ndlc, int phy_headroom,
+		       int phy_tailroom)
+{
+	struct st21nfcb_nci_info *info;
+	int r;
+	u32 protocols;
+
+	info = devm_kzalloc(ndlc->dev,
+			sizeof(struct st21nfcb_nci_info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	protocols = NFC_PROTO_JEWEL_MASK
+		| NFC_PROTO_MIFARE_MASK
+		| NFC_PROTO_FELICA_MASK
+		| NFC_PROTO_ISO14443_MASK
+		| NFC_PROTO_ISO14443_B_MASK
+		| NFC_PROTO_NFC_DEP_MASK;
+
+	ndlc->ndev = nci_allocate_device(&st21nfcb_nci_ops, protocols,
+					phy_headroom, phy_tailroom);
+	if (!ndlc->ndev) {
+		pr_err("Cannot allocate nfc ndev\n");
+		r = -ENOMEM;
+		goto err_alloc_ndev;
+	}
+	info->ndlc = ndlc;
+
+	nci_set_drvdata(ndlc->ndev, info);
+
+	r = nci_register_device(ndlc->ndev);
+	if (r)
+		goto err_regdev;
+
+	return r;
+err_regdev:
+	nci_free_device(ndlc->ndev);
+
+err_alloc_ndev:
+	kfree(info);
+	return r;
+}
+EXPORT_SYMBOL_GPL(st21nfcb_nci_probe);
+
+void st21nfcb_nci_remove(struct nci_dev *ndev)
+{
+	struct st21nfcb_nci_info *info = nci_get_drvdata(ndev);
+
+	nci_unregister_device(ndev);
+	nci_free_device(ndev);
+	kfree(info);
+}
+EXPORT_SYMBOL_GPL(st21nfcb_nci_remove);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);