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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>
This commit is contained in:
Samuel Ortiz
parent
71054c7db1
commit
e0af11fa0d
@ -22,3 +22,14 @@ config NFC_MICROREAD_I2C
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If you choose to build a module, it'll be called microread_i2c.
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Say N if unsure.
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config NFC_MICROREAD_MEI
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tristate "NFC Microread MEI support"
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depends on NFC_MICROREAD && INTEL_MEI_BUS_NFC
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---help---
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This module adds support for the mei interface of adapters using
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Inside microread chipsets. Select this if your microread chipset
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is handled by Intel's Management Engine Interface on your platform.
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If you choose to build a module, it'll be called microread_mei.
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Say N if unsure.
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@ -3,6 +3,8 @@
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#
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microread_i2c-objs = i2c.o
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microread_mei-objs = mei.o
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obj-$(CONFIG_NFC_MICROREAD) += microread.o
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obj-$(CONFIG_NFC_MICROREAD_I2C) += microread_i2c.o
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obj-$(CONFIG_NFC_MICROREAD_MEI) += microread_mei.o
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241
drivers/nfc/microread/mei.c
Normal file
241
drivers/nfc/microread/mei.c
Normal file
@ -0,0 +1,241 @@
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/*
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* HCI based Driver for Inside Secure microread NFC Chip
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*
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* Copyright (C) 2013 Intel Corporation. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the
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* Free Software Foundation, Inc.,
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* 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/interrupt.h>
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#include <linux/gpio.h>
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#include <linux/mei_bus.h>
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#include <linux/nfc.h>
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#include <net/nfc/hci.h>
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#include <net/nfc/llc.h>
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#include "microread.h"
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#define MICROREAD_DRIVER_NAME "microread"
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#define MICROREAD_UUID UUID_LE(0x0bb17a78, 0x2a8e, 0x4c50, 0x94, \
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0xd4, 0x50, 0x26, 0x67, 0x23, 0x77, 0x5c)
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struct mei_nfc_hdr {
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u8 cmd;
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u8 status;
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u16 req_id;
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u32 reserved;
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u16 data_size;
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} __attribute__((packed));
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#define MEI_NFC_HEADER_SIZE 10
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#define MEI_NFC_MAX_HCI_PAYLOAD 300
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#define MEI_NFC_MAX_READ (MEI_NFC_HEADER_SIZE + MEI_NFC_MAX_HCI_PAYLOAD)
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struct microread_mei_phy {
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struct mei_bus_client *client;
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struct nfc_hci_dev *hdev;
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int powered;
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int hard_fault; /*
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* < 0 if hardware error occured (e.g. i2c err)
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* and prevents normal operation.
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*/
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};
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#define MEI_DUMP_SKB_IN(info, skb) \
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do { \
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pr_debug("%s:\n", info); \
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print_hex_dump(KERN_DEBUG, "mei in : ", DUMP_PREFIX_OFFSET, \
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16, 1, (skb)->data, (skb)->len, 0); \
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} while (0)
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#define MEI_DUMP_SKB_OUT(info, skb) \
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do { \
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pr_debug("%s:\n", info); \
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print_hex_dump(KERN_DEBUG, "mei out: ", DUMP_PREFIX_OFFSET, \
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16, 1, (skb)->data, (skb)->len, 0); \
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} while (0)
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static int microread_mei_enable(void *phy_id)
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{
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struct microread_mei_phy *phy = phy_id;
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pr_info(DRIVER_DESC ": %s\n", __func__);
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phy->powered = 1;
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return 0;
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}
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static void microread_mei_disable(void *phy_id)
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{
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struct microread_mei_phy *phy = phy_id;
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pr_info(DRIVER_DESC ": %s\n", __func__);
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phy->powered = 0;
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}
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/*
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* Writing a frame must not return the number of written bytes.
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* It must return either zero for success, or <0 for error.
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* In addition, it must not alter the skb
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*/
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static int microread_mei_write(void *phy_id, struct sk_buff *skb)
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{
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struct microread_mei_phy *phy = phy_id;
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int r;
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MEI_DUMP_SKB_OUT("mei frame sent", skb);
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r = mei_bus_send(phy->client, skb->data, skb->len);
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if (r > 0)
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r = 0;
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return r;
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}
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static void microread_event_cb(struct mei_bus_client *client, u32 events,
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void *context)
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{
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struct microread_mei_phy *phy = context;
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if (phy->hard_fault != 0)
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return;
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if (events & BIT(MEI_BUS_EVENT_RX)) {
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struct sk_buff *skb;
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int reply_size;
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skb = alloc_skb(MEI_NFC_MAX_READ, GFP_KERNEL);
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if (!skb)
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return;
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reply_size = mei_bus_recv(client, skb->data, MEI_NFC_MAX_READ);
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if (reply_size < MEI_NFC_HEADER_SIZE) {
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kfree(skb);
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return;
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}
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skb_put(skb, reply_size);
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skb_pull(skb, MEI_NFC_HEADER_SIZE);
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MEI_DUMP_SKB_IN("mei frame read", skb);
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nfc_hci_recv_frame(phy->hdev, skb);
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}
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}
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static struct nfc_phy_ops mei_phy_ops = {
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.write = microread_mei_write,
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.enable = microread_mei_enable,
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.disable = microread_mei_disable,
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};
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static int microread_mei_probe(struct mei_bus_client *client)
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{
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struct microread_mei_phy *phy;
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int r;
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pr_info("Probing NFC microread\n");
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phy = kzalloc(sizeof(struct microread_mei_phy), GFP_KERNEL);
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if (!phy) {
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pr_err("Cannot allocate memory for microread mei phy.\n");
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return -ENOMEM;
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}
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phy->client = client;
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mei_bus_set_clientdata(client, phy);
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r = mei_bus_register_event_cb(client, microread_event_cb, phy);
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if (r) {
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pr_err(MICROREAD_DRIVER_NAME ": event cb registration failed\n");
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goto err_out;
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}
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r = microread_probe(phy, &mei_phy_ops, LLC_NOP_NAME,
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MEI_NFC_HEADER_SIZE, 0, MEI_NFC_MAX_HCI_PAYLOAD,
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&phy->hdev);
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if (r < 0)
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goto err_out;
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return 0;
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err_out:
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kfree(phy);
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return r;
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}
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static int microread_mei_remove(struct mei_bus_client *client)
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{
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struct microread_mei_phy *phy = mei_bus_get_clientdata(client);
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pr_info("Removing microread\n");
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microread_remove(phy->hdev);
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if (phy->powered)
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microread_mei_disable(phy);
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kfree(phy);
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return 0;
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}
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static struct mei_bus_driver microread_driver = {
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.driver = {
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.name = MICROREAD_DRIVER_NAME,
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},
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.id = {
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.name = MICROREAD_DRIVER_NAME,
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.uuid = MICROREAD_UUID,
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},
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.probe = microread_mei_probe,
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.remove = microread_mei_remove,
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};
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static int microread_mei_init(void)
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{
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int r;
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pr_debug(DRIVER_DESC ": %s\n", __func__);
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r = mei_driver_register(µread_driver);
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if (r) {
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pr_err(MICROREAD_DRIVER_NAME ": driver registration failed\n");
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return r;
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}
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return 0;
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}
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static void microread_mei_exit(void)
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{
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mei_driver_unregister(µread_driver);
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}
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module_init(microread_mei_init);
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module_exit(microread_mei_exit);
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MODULE_LICENSE("GPL");
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MODULE_DESCRIPTION(DRIVER_DESC);
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