NFC: microread: Add MEI physical layer
On some peculiar worlds, microreads are found hidden behind MEIs and needs
to be accessed through the ME bus.
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/drivers/nfc/microread/mei.c b/drivers/nfc/microread/mei.c
new file mode 100644
index 0000000..c078e56
--- /dev/null
+++ b/drivers/nfc/microread/mei.c
@@ -0,0 +1,241 @@
+/*
+ * HCI based Driver for Inside Secure microread NFC Chip
+ *
+ * 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/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/mei_bus.h>
+
+#include <linux/nfc.h>
+#include <net/nfc/hci.h>
+#include <net/nfc/llc.h>
+
+#include "microread.h"
+
+#define MICROREAD_DRIVER_NAME "microread"
+
+#define MICROREAD_UUID UUID_LE(0x0bb17a78, 0x2a8e, 0x4c50, 0x94, \
+ 0xd4, 0x50, 0x26, 0x67, 0x23, 0x77, 0x5c)
+
+struct mei_nfc_hdr {
+ u8 cmd;
+ u8 status;
+ u16 req_id;
+ u32 reserved;
+ u16 data_size;
+} __attribute__((packed));
+
+#define MEI_NFC_HEADER_SIZE 10
+#define MEI_NFC_MAX_HCI_PAYLOAD 300
+#define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD)
+
+struct microread_mei_phy {
+ struct mei_bus_client *client;
+ struct nfc_hci_dev *hdev;
+
+ int powered;
+
+ int hard_fault; /*
+ * < 0 if hardware error occured (e.g. i2c err)
+ * and prevents normal operation.
+ */
+};
+
+#define MEI_DUMP_SKB_IN(info, skb) \
+do { \
+ pr_debug("%s:\n", info); \
+ print_hex_dump(KERN_DEBUG, "mei in : ", DUMP_PREFIX_OFFSET, \
+ 16, 1, (skb)->data, (skb)->len, 0); \
+} while (0)
+
+#define MEI_DUMP_SKB_OUT(info, skb) \
+do { \
+ pr_debug("%s:\n", info); \
+ print_hex_dump(KERN_DEBUG, "mei out: ", DUMP_PREFIX_OFFSET, \
+ 16, 1, (skb)->data, (skb)->len, 0); \
+} while (0)
+
+static int microread_mei_enable(void *phy_id)
+{
+ struct microread_mei_phy *phy = phy_id;
+
+ pr_info(DRIVER_DESC ": %s\n", __func__);
+
+ phy->powered = 1;
+
+ return 0;
+}
+
+static void microread_mei_disable(void *phy_id)
+{
+ struct microread_mei_phy *phy = phy_id;
+
+ pr_info(DRIVER_DESC ": %s\n", __func__);
+
+ phy->powered = 0;
+}
+
+/*
+ * 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 microread_mei_write(void *phy_id, struct sk_buff *skb)
+{
+ struct microread_mei_phy *phy = phy_id;
+ int r;
+
+ MEI_DUMP_SKB_OUT("mei frame sent", skb);
+
+ r = mei_bus_send(phy->client, skb->data, skb->len);
+ if (r > 0)
+ r = 0;
+
+ return r;
+}
+
+static void microread_event_cb(struct mei_bus_client *client, u32 events,
+ void *context)
+{
+ struct microread_mei_phy *phy = context;
+
+ if (phy->hard_fault != 0)
+ return;
+
+ if (events & BIT(MEI_BUS_EVENT_RX)) {
+ struct sk_buff *skb;
+ int reply_size;
+
+ skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
+ if (!skb)
+ return;
+
+ reply_size = mei_bus_recv(client, 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);
+ }
+}
+
+static struct nfc_phy_ops mei_phy_ops = {
+ .write = microread_mei_write,
+ .enable = microread_mei_enable,
+ .disable = microread_mei_disable,
+};
+
+static int microread_mei_probe(struct mei_bus_client *client)
+{
+ struct microread_mei_phy *phy;
+ int r;
+
+ pr_info("Probing NFC microread\n");
+
+ phy = kzalloc(sizeof(struct microread_mei_phy), GFP_KERNEL);
+ if (!phy) {
+ pr_err("Cannot allocate memory for microread mei phy.\n");
+ return -ENOMEM;
+ }
+
+ phy->client = client;
+ mei_bus_set_clientdata(client, phy);
+
+ r = mei_bus_register_event_cb(client, microread_event_cb, phy);
+ if (r) {
+ pr_err(MICROREAD_DRIVER_NAME ": event cb registration failed\n");
+ goto err_out;
+ }
+
+ r = microread_probe(phy, &mei_phy_ops, LLC_NOP_NAME,
+ MEI_NFC_HEADER_SIZE, 0, MEI_NFC_MAX_HCI_PAYLOAD,
+ &phy->hdev);
+ if (r < 0)
+ goto err_out;
+
+ return 0;
+
+err_out:
+ kfree(phy);
+
+ return r;
+}
+
+static int microread_mei_remove(struct mei_bus_client *client)
+{
+ struct microread_mei_phy *phy = mei_bus_get_clientdata(client);
+
+ pr_info("Removing microread\n");
+
+ microread_remove(phy->hdev);
+
+ if (phy->powered)
+ microread_mei_disable(phy);
+
+ kfree(phy);
+
+ return 0;
+}
+
+static struct mei_bus_driver microread_driver = {
+ .driver = {
+ .name = MICROREAD_DRIVER_NAME,
+ },
+ .id = {
+ .name = MICROREAD_DRIVER_NAME,
+ .uuid = MICROREAD_UUID,
+ },
+
+ .probe = microread_mei_probe,
+ .remove = microread_mei_remove,
+};
+
+static int microread_mei_init(void)
+{
+ int r;
+
+ pr_debug(DRIVER_DESC ": %s\n", __func__);
+
+ r = mei_driver_register(µread_driver);
+ if (r) {
+ pr_err(MICROREAD_DRIVER_NAME ": driver registration failed\n");
+ return r;
+ }
+
+ return 0;
+}
+
+static void microread_mei_exit(void)
+{
+ mei_driver_unregister(µread_driver);
+}
+
+module_init(microread_mei_init);
+module_exit(microread_mei_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION(DRIVER_DESC);