NFC: mei: Add a common mei bus API for NFC drivers

This isolates the common code that is required to use an mei bus nfc
device from an NFC HCI drivers. This prepares for future drivers for
NFC chips connected behind an Intel Management Engine controller.
The microread_mei HCI driver is also modified to use that common code.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

1 files changed, 164 insertions, 0 deletions

diff --git a/drivers/nfc/mei_phy.c b/drivers/nfc/mei_phy.c
new file mode 100644
index 000000000000..b8f8abc422f0
--- /dev/null
+++ b/drivers/nfc/mei_phy.c
@@ -0,0 +1,164 @@
+/*
+ * MEI Library for mei bus nfc device access
+ *
+ * Copyright (C) 2013  Intel Corporation. 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, write to the
+ * Free Software Foundation, Inc.,
+ * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <linux/module.h>
+#include <linux/slab.h>
+#include <linux/nfc.h>
+
+#include "mei_phy.h"
+
+struct mei_nfc_hdr {
+	u8 cmd;
+	u8 status;
+	u16 req_id;
+	u32 reserved;
+	u16 data_size;
+} __attribute__((packed));
+
+#define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD)
+
+#define MEI_DUMP_SKB_IN(info, skb)				\
+do {								\
+	pr_debug("%s:\n", info);				\
+	print_hex_dump_debug("mei in : ", DUMP_PREFIX_OFFSET,	\
+			16, 1, (skb)->data, (skb)->len, false);	\
+} while (0)
+
+#define MEI_DUMP_SKB_OUT(info, skb)				\
+do {								\
+	pr_debug("%s:\n", info);				\
+	print_hex_dump_debug("mei out: ", DUMP_PREFIX_OFFSET,	\
+		       16, 1, (skb)->data, (skb)->len, false);	\
+} while (0)
+
+int nfc_mei_phy_enable(void *phy_id)
+{
+	int r;
+	struct nfc_mei_phy *phy = phy_id;
+
+	pr_info("%s\n", __func__);
+
+	if (phy->powered == 1)
+		return 0;
+
+	r = mei_cl_enable_device(phy->device);
+	if (r < 0) {
+                pr_err("MEI_PHY: Could not enable device\n");
+                return r;
+	}
+
+	phy->powered = 1;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(nfc_mei_phy_enable);
+
+void nfc_mei_phy_disable(void *phy_id)
+{
+	struct nfc_mei_phy *phy = phy_id;
+
+	pr_info("%s\n", __func__);
+
+	mei_cl_disable_device(phy->device);
+
+	phy->powered = 0;
+}
+EXPORT_SYMBOL_GPL(nfc_mei_phy_disable);
+
+/*
+ * Writing a frame must not return the number of written bytes.
+ * It must return either zero for success, or <0 for error.
+ * In addition, it must not alter the skb
+ */
+static int nfc_mei_phy_write(void *phy_id, struct sk_buff *skb)
+{
+	struct nfc_mei_phy *phy = phy_id;
+	int r;
+
+	MEI_DUMP_SKB_OUT("mei frame sent", skb);
+
+	r = mei_cl_send(phy->device, skb->data, skb->len);
+	if (r > 0)
+		r = 0;
+
+	return r;
+}
+
+void nfc_mei_event_cb(struct mei_cl_device *device, u32 events, void *context)
+{
+	struct nfc_mei_phy *phy = context;
+
+	if (phy->hard_fault != 0)
+		return;
+
+	if (events & BIT(MEI_CL_EVENT_RX)) {
+		struct sk_buff *skb;
+		int reply_size;
+
+		skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
+		if (!skb)
+			return;
+
+		reply_size = mei_cl_recv(device, skb->data, MEI_NFC_MAX_READ);
+		if (reply_size < MEI_NFC_HEADER_SIZE) {
+			kfree(skb);
+			return;
+		}
+
+		skb_put(skb, reply_size);
+		skb_pull(skb, MEI_NFC_HEADER_SIZE);
+
+		MEI_DUMP_SKB_IN("mei frame read", skb);
+
+		nfc_hci_recv_frame(phy->hdev, skb);
+	}
+}
+EXPORT_SYMBOL_GPL(nfc_mei_event_cb);
+
+struct nfc_phy_ops mei_phy_ops = {
+	.write = nfc_mei_phy_write,
+	.enable = nfc_mei_phy_enable,
+	.disable = nfc_mei_phy_disable,
+};
+EXPORT_SYMBOL_GPL(mei_phy_ops);
+
+struct nfc_mei_phy *nfc_mei_phy_alloc(struct mei_cl_device *device)
+{
+	struct nfc_mei_phy *phy;
+
+	phy = kzalloc(sizeof(struct nfc_mei_phy), GFP_KERNEL);
+	if (!phy)
+		return NULL;
+
+	phy->device = device;
+	mei_cl_set_drvdata(device, phy);
+
+	return phy;
+}
+EXPORT_SYMBOL_GPL(nfc_mei_phy_alloc);
+
+void nfc_mei_phy_free(struct nfc_mei_phy *phy)
+{
+	kfree(phy);
+}
+EXPORT_SYMBOL_GPL(nfc_mei_phy_free);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("mei bus NFC device interface");