diff options
| -rw-r--r-- | drivers/nfc/microread/Kconfig | 11 | ||||
| -rw-r--r-- | drivers/nfc/microread/Makefile | 3 | ||||
| -rw-r--r-- | drivers/nfc/microread/i2c.c | 340 |
3 files changed, 354 insertions, 0 deletions
diff --git a/drivers/nfc/microread/Kconfig b/drivers/nfc/microread/Kconfig index 5b89d01..cd6744b 100644 --- a/drivers/nfc/microread/Kconfig +++ b/drivers/nfc/microread/Kconfig @@ -11,3 +11,14 @@ config NFC_MICROREAD To compile this driver as a module, choose m here. The module will be called microread. Say N if unsure. + +config NFC_MICROREAD_I2C + tristate "NFC Microread i2c support" + depends on NFC_MICROREAD && I2C && NFC_SHDLC + ---help--- + This module adds support for the i2c interface of adapters using + Inside microread chipsets. Select this if your platform is using + the i2c bus. + + If you choose to build a module, it'll be called microread_i2c. + Say N if unsure. diff --git a/drivers/nfc/microread/Makefile b/drivers/nfc/microread/Makefile index 9ce2c53..74c1851 100644 --- a/drivers/nfc/microread/Makefile +++ b/drivers/nfc/microread/Makefile @@ -2,4 +2,7 @@ # Makefile for Microread HCI based NFC driver # +microread_i2c-objs = i2c.o + obj-$(CONFIG_NFC_MICROREAD) += microread.o +obj-$(CONFIG_NFC_MICROREAD_I2C) += microread_i2c.o diff --git a/drivers/nfc/microread/i2c.c b/drivers/nfc/microread/i2c.c new file mode 100644 index 0000000..1010894 --- /dev/null +++ b/drivers/nfc/microread/i2c.c @@ -0,0 +1,340 @@ +/* + * HCI based Driver for Inside Secure microread NFC Chip - i2c layer + * + * 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/i2c.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/interrupt.h> +#include <linux/gpio.h> + +#include <linux/nfc.h> +#include <net/nfc/hci.h> +#include <net/nfc/llc.h> + +#include "microread.h" + +#define MICROREAD_I2C_DRIVER_NAME "microread" + +#define MICROREAD_I2C_FRAME_HEADROOM 1 +#define MICROREAD_I2C_FRAME_TAILROOM 1 + +/* framing in HCI mode */ +#define MICROREAD_I2C_LLC_LEN 1 +#define MICROREAD_I2C_LLC_CRC 1 +#define MICROREAD_I2C_LLC_LEN_CRC (MICROREAD_I2C_LLC_LEN + \ + MICROREAD_I2C_LLC_CRC) +#define MICROREAD_I2C_LLC_MIN_SIZE (1 + MICROREAD_I2C_LLC_LEN_CRC) +#define MICROREAD_I2C_LLC_MAX_PAYLOAD 29 +#define MICROREAD_I2C_LLC_MAX_SIZE (MICROREAD_I2C_LLC_LEN_CRC + 1 + \ + MICROREAD_I2C_LLC_MAX_PAYLOAD) + +struct microread_i2c_phy { + struct i2c_client *i2c_dev; + struct nfc_hci_dev *hdev; + + int irq; + + int hard_fault; /* + * < 0 if hardware error occured (e.g. i2c err) + * and prevents normal operation. + */ +}; + +#define I2C_DUMP_SKB(info, skb) \ +do { \ + pr_debug("%s:\n", info); \ + print_hex_dump(KERN_DEBUG, "i2c: ", DUMP_PREFIX_OFFSET, \ + 16, 1, (skb)->data, (skb)->len, 0); \ +} while (0) + +static void microread_i2c_add_len_crc(struct sk_buff *skb) +{ + int i; + u8 crc = 0; + int len; + + len = skb->len; + *skb_push(skb, 1) = len; + + for (i = 0; i < skb->len; i++) + crc = crc ^ skb->data[i]; + + *skb_put(skb, 1) = crc; +} + +static void microread_i2c_remove_len_crc(struct sk_buff *skb) +{ + skb_pull(skb, MICROREAD_I2C_FRAME_HEADROOM); + skb_trim(skb, MICROREAD_I2C_FRAME_TAILROOM); +} + +static int check_crc(struct sk_buff *skb) +{ + int i; + u8 crc = 0; + + for (i = 0; i < skb->len - 1; i++) + crc = crc ^ skb->data[i]; + + if (crc != skb->data[skb->len-1]) { + pr_err(MICROREAD_I2C_DRIVER_NAME + ": CRC error 0x%x != 0x%x\n", + crc, skb->data[skb->len-1]); + + pr_info(DRIVER_DESC ": %s : BAD CRC\n", __func__); + + return -EPERM; + } + + return 0; +} + +static int microread_i2c_enable(void *phy_id) +{ + return 0; +} + +static void microread_i2c_disable(void *phy_id) +{ + return; +} + +static int microread_i2c_write(void *phy_id, struct sk_buff *skb) +{ + int r; + struct microread_i2c_phy *phy = phy_id; + struct i2c_client *client = phy->i2c_dev; + + if (phy->hard_fault != 0) + return phy->hard_fault; + + usleep_range(3000, 6000); + + microread_i2c_add_len_crc(skb); + + I2C_DUMP_SKB("i2c frame written", skb); + + r = i2c_master_send(client, skb->data, skb->len); + + if (r == -EREMOTEIO) { /* Retry, chip was in standby */ + usleep_range(6000, 10000); + r = i2c_master_send(client, skb->data, skb->len); + } + + if (r >= 0) { + if (r != skb->len) + r = -EREMOTEIO; + else + r = 0; + } + + microread_i2c_remove_len_crc(skb); + + return r; +} + + +static int microread_i2c_read(struct microread_i2c_phy *phy, + struct sk_buff **skb) +{ + int r; + u8 len; + u8 tmp[MICROREAD_I2C_LLC_MAX_SIZE - 1]; + struct i2c_client *client = phy->i2c_dev; + + pr_debug("%s\n", __func__); + + r = i2c_master_recv(client, &len, 1); + if (r != 1) { + dev_err(&client->dev, "cannot read len byte\n"); + return -EREMOTEIO; + } + + if ((len < MICROREAD_I2C_LLC_MIN_SIZE) || + (len > MICROREAD_I2C_LLC_MAX_SIZE)) { + dev_err(&client->dev, "invalid len byte\n"); + pr_err("invalid len byte\n"); + r = -EBADMSG; + goto flush; + } + + *skb = alloc_skb(1 + len, GFP_KERNEL); + if (*skb == NULL) { + r = -ENOMEM; + goto flush; + } + + *skb_put(*skb, 1) = len; + + r = i2c_master_recv(client, skb_put(*skb, len), len); + if (r != len) { + kfree_skb(*skb); + return -EREMOTEIO; + } + + I2C_DUMP_SKB("cc frame read", *skb); + + r = check_crc(*skb); + if (r != 0) { + kfree_skb(*skb); + r = -EBADMSG; + goto flush; + } + + skb_pull(*skb, 1); + skb_trim(*skb, (*skb)->len - MICROREAD_I2C_FRAME_TAILROOM); + + usleep_range(3000, 6000); + + return 0; + +flush: + if (i2c_master_recv(client, tmp, sizeof(tmp)) < 0) + r = -EREMOTEIO; + + usleep_range(3000, 6000); + + return r; +} + +static irqreturn_t microread_i2c_irq_thread_fn(int irq, void *phy_id) +{ + struct microread_i2c_phy *phy = phy_id; + struct i2c_client *client; + struct sk_buff *skb = NULL; + int r; + + if (!phy || irq != phy->i2c_dev->irq) { + WARN_ON_ONCE(1); + return IRQ_NONE; + } + + client = phy->i2c_dev; + dev_dbg(&client->dev, "IRQ\n"); + + if (phy->hard_fault != 0) + return IRQ_HANDLED; + + r = microread_i2c_read(phy, &skb); + if (r == -EREMOTEIO) { + phy->hard_fault = r; + + nfc_hci_recv_frame(phy->hdev, NULL); + + return IRQ_HANDLED; + } else if ((r == -ENOMEM) || (r == -EBADMSG)) { + return IRQ_HANDLED; + } + + nfc_hci_recv_frame(phy->hdev, skb); + + return IRQ_HANDLED; +} + +static struct nfc_phy_ops i2c_phy_ops = { + .write = microread_i2c_write, + .enable = microread_i2c_enable, + .disable = microread_i2c_disable, +}; + +static int microread_i2c_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct microread_i2c_phy *phy; + struct microread_nfc_platform_data *pdata = + dev_get_platdata(&client->dev); + int r; + + dev_dbg(&client->dev, "client %p", client); + + if (!pdata) { + dev_err(&client->dev, "client %p: missing platform data", + client); + return -EINVAL; + } + + phy = devm_kzalloc(&client->dev, sizeof(struct microread_i2c_phy), + GFP_KERNEL); + if (!phy) { + dev_err(&client->dev, "Can't allocate microread phy"); + return -ENOMEM; + } + + i2c_set_clientdata(client, phy); + phy->i2c_dev = client; + + r = request_threaded_irq(client->irq, NULL, microread_i2c_irq_thread_fn, + IRQF_TRIGGER_RISING | IRQF_ONESHOT, + MICROREAD_I2C_DRIVER_NAME, phy); + if (r) { + dev_err(&client->dev, "Unable to register IRQ handler"); + return r; + } + + r = microread_probe(phy, &i2c_phy_ops, LLC_SHDLC_NAME, + MICROREAD_I2C_FRAME_HEADROOM, + MICROREAD_I2C_FRAME_TAILROOM, + MICROREAD_I2C_LLC_MAX_PAYLOAD, &phy->hdev); + if (r < 0) + goto err_irq; + + dev_info(&client->dev, "Probed"); + + return 0; + +err_irq: + free_irq(client->irq, phy); + + return r; +} + +static int microread_i2c_remove(struct i2c_client *client) +{ + struct microread_i2c_phy *phy = i2c_get_clientdata(client); + + dev_dbg(&client->dev, "%s\n", __func__); + + microread_remove(phy->hdev); + + free_irq(client->irq, phy); + + return 0; +} + +static struct i2c_device_id microread_i2c_id[] = { + { MICROREAD_I2C_DRIVER_NAME, 0}, + { } +}; +MODULE_DEVICE_TABLE(i2c, microread_i2c_id); + +static struct i2c_driver microread_i2c_driver = { + .driver = { + .name = MICROREAD_I2C_DRIVER_NAME, + }, + .probe = microread_i2c_probe, + .remove = microread_i2c_remove, + .id_table = microread_i2c_id, +}; + +module_i2c_driver(microread_i2c_driver); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION(DRIVER_DESC); |
