This adds the UART phy interface for the pn533 driver. The pn533 driver can be used through UART interface this way. It is implemented as a tty line discipline.
Signed-off-by: Lars Poeschel <[email protected]> --- drivers/nfc/pn533/Kconfig | 10 + drivers/nfc/pn533/Makefile | 2 + drivers/nfc/pn533/pn533.h | 8 + drivers/nfc/pn533/uart.c | 399 +++++++++++++++++++++++++++++++++++++ include/uapi/linux/tty.h | 1 + 5 files changed, 420 insertions(+) create mode 100644 drivers/nfc/pn533/uart.c diff --git a/drivers/nfc/pn533/Kconfig b/drivers/nfc/pn533/Kconfig index d94122dd30e4..da3ea2dbaa8a 100644 --- a/drivers/nfc/pn533/Kconfig +++ b/drivers/nfc/pn533/Kconfig @@ -25,3 +25,13 @@ config NFC_PN533_I2C If you choose to build a module, it'll be called pn533_i2c. Say N if unsure. + +config NFC_PN532_UART + tristate "NFC PN532 device support (UART)" + select NFC_PN533 + ---help--- + This module adds support for the NXP pn532 UART interface. + Select this if your platform is using the UART bus. + + If you choose to build a module, it'll be called pn532_uart. + Say N if unsure. diff --git a/drivers/nfc/pn533/Makefile b/drivers/nfc/pn533/Makefile index 51d24c622fcb..bdfd6860d5e4 100644 --- a/drivers/nfc/pn533/Makefile +++ b/drivers/nfc/pn533/Makefile @@ -3,7 +3,9 @@ # pn533_usb-objs = usb.o pn533_i2c-objs = i2c.o +pn532_uart-objs = uart.o obj-$(CONFIG_NFC_PN533) += pn533.o obj-$(CONFIG_NFC_PN533_USB) += pn533_usb.o obj-$(CONFIG_NFC_PN533_I2C) += pn533_i2c.o +obj-$(CONFIG_NFC_PN532_UART) += pn532_uart.o diff --git a/drivers/nfc/pn533/pn533.h b/drivers/nfc/pn533/pn533.h index 88d569666c51..ca00508eefff 100644 --- a/drivers/nfc/pn533/pn533.h +++ b/drivers/nfc/pn533/pn533.h @@ -55,6 +55,11 @@ /* Preamble (1), SoPC (2), ACK Code (2), Postamble (1) */ #define PN533_STD_FRAME_ACK_SIZE 6 +/* + * Preamble (1), SoPC (2), Packet Length (1), Packet Length Checksum (1), + * Specific Application Level Error Code (1) , Postamble (1) + */ +#define PN533_STD_ERROR_FRAME_SIZE 8 #define PN533_STD_FRAME_CHECKSUM(f) (f->data[f->datalen]) #define PN533_STD_FRAME_POSTAMBLE(f) (f->data[f->datalen + 1]) /* Half start code (3), LEN (4) should be 0xffff for extended frame */ @@ -96,6 +101,9 @@ #define PN533_CMD_MI_MASK 0x40 #define PN533_CMD_RET_SUCCESS 0x00 +#define PN533_FRAME_DATALEN_ACK 0x00 +#define PN533_FRAME_DATALEN_ERROR 0x01 +#define PN533_FRAME_DATALEN_EXTENDED 0xFF enum pn533_protocol_type { PN533_PROTO_REQ_ACK_RESP = 0, diff --git a/drivers/nfc/pn533/uart.c b/drivers/nfc/pn533/uart.c new file mode 100644 index 000000000000..b5f995988cae --- /dev/null +++ b/drivers/nfc/pn533/uart.c @@ -0,0 +1,399 @@ +/* + * Driver for NXP PN532 NFC Chip - UART transport layer + * + * Copyright (C) 2018 Lemonage Software GmbH + * Author: Lars Poeschel <[email protected]> + * All rights reserved. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * 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/device.h> +#include <linux/kernel.h> +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/tty.h> +#include <linux/nfc.h> +#include <linux/netdevice.h> +#include <net/nfc/nfc.h> +#include "pn533.h" + +#define VERSION "0.1" + +#define PN532_I2C_DRIVER_NAME "pn532_uart" + +#define PN532_MAGIC 0x162f +#define PN532_UART_SKB_BUFF_LEN (PN533_CMD_DATAEXCH_DATA_MAXLEN * 2) + +struct pn532_uart_phy { + int magic; + struct tty_struct *tty; + struct sk_buff *recv_skb; + struct pn533 *priv; + int send_wakeup; + struct timer_list cmd_timeout; + struct sk_buff *cur_out_buf; + struct workqueue_struct *wq_open_tty; + struct work_struct open_tty_work; + struct completion init_done; +}; + +static int pn532_uart_send_frame(struct pn533 *dev, + struct sk_buff *out) +{ + static const u8 wakeup[] = { + 0x55, 0x55, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; + /* wakeup sequence and dummy bytes for waiting time */ + struct pn532_uart_phy *pn532 = dev->phy; + struct tty_struct *tty = pn532->tty; + int count; + + if (pn532->priv == NULL) + pn532->priv = dev; + + print_hex_dump_debug("PN532_uart TX: ", DUMP_PREFIX_NONE, 16, 1, + out->data, out->len, false); + + pn532->cur_out_buf = out; + set_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); + if (pn532->send_wakeup) + count = tty->ops->write(tty, wakeup, sizeof(wakeup)); + + count = tty->ops->write(tty, out->data, out->len); + if (PN533_FRAME_CMD(((struct pn533_std_frame *)out->data)) == + PN533_CMD_SAM_CONFIGURATION) + pn532->send_wakeup = 0; + + mod_timer(&pn532->cmd_timeout, HZ / 40 + jiffies); + return 0; +} + +static int pn532_uart_send_ack(struct pn533 *dev, gfp_t flags) +{ + struct pn532_uart_phy *phy = dev->phy; + static const u8 ack[PN533_STD_FRAME_ACK_SIZE] = { + 0x00, 0x00, 0xff, 0x00, 0xff, 0x00}; + /* spec 7.1.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */ + int rc; + + set_bit(TTY_DO_WRITE_WAKEUP, &phy->tty->flags); + rc = phy->tty->ops->write(phy->tty, ack, sizeof(ack)); + + return 0; +} + +static void pn532_uart_abort_cmd(struct pn533 *dev, gfp_t flags) +{ + /* An ack will cancel the last issued command */ + pn532_uart_send_ack(dev, flags); + + /* schedule cmd_complete_work to finish current command execution */ + pn533_recv_frame(dev, NULL, -ENOENT); +} + +static struct pn533_phy_ops uart_phy_ops = { + .send_frame = pn532_uart_send_frame, + .send_ack = pn532_uart_send_ack, + .abort_cmd = pn532_uart_abort_cmd, +}; + +static void pn532_cmd_timeout(struct timer_list *t) +{ + struct pn532_uart_phy *dev = from_timer(dev, t, cmd_timeout); + + pn532_uart_send_frame(dev->priv, dev->cur_out_buf); +} + +static void pn532_finalize_setup(struct work_struct *work) +{ + struct pn532_uart_phy *pn532 = + container_of(work, struct pn532_uart_phy, open_tty_work); + int err; + + err = pn533_finalize_setup(pn532->priv); + if (err) { + complete_all(&pn532->init_done); + return; + } + + pn532->magic = PN532_MAGIC; + complete_all(&pn532->init_done); +} + +static int pn532_open(struct tty_struct *tty) +{ + struct pn532_uart_phy *pn532; + struct pn533 *priv; + int err; + + if (tty->ops->write == NULL) + return -EOPNOTSUPP; + + pn532 = tty->disc_data; + err = -EEXIST; + /* First make sure we're not already connected. */ + if (pn532 && pn532->magic == PN532_MAGIC) + goto err_exit; + + err = -ENOMEM; + pn532 = kzalloc(sizeof(*pn532), GFP_KERNEL); + if (pn532 == NULL) + goto err_exit; + + pn532->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL); + if (pn532->recv_skb == NULL) + goto err_free; + + pn532->tty = tty; + INIT_WORK(&pn532->open_tty_work, pn532_finalize_setup); + pn532->wq_open_tty = alloc_workqueue("pn532_uart_finalize_setup", 0, 0); + if (pn532->wq_open_tty == NULL) + goto err_skb; + + priv = pn533_register_device(PN533_DEVICE_PN532, + PN533_NO_TYPE_B_PROTOCOLS, + PN533_PROTO_REQ_ACK_RESP, + pn532, &uart_phy_ops, NULL, + pn532->tty->dev, + tty->dev); + + if (IS_ERR(priv)) { + err = PTR_ERR(priv); + goto err_wq; + } + + pn532->priv = priv; + tty->disc_data = pn532; + init_completion(&pn532->init_done); + + /* Done. We have linked the TTY line to a channel. */ + pn532->tty->receive_room = 262 * 2; + pn532->send_wakeup = 1; + timer_setup(&pn532->cmd_timeout, pn532_cmd_timeout, 0); + queue_work(pn532->wq_open_tty, &pn532->open_tty_work); + /* TTY layer expects 0 on success */ + return 0; + +err_wq: + destroy_workqueue(pn532->wq_open_tty); +err_skb: + kfree_skb(pn532->recv_skb); +err_free: + kfree(pn532); +err_exit: + /* Count references from TTY module */ + return err; +} + +static void pn532_close(struct tty_struct *tty) +{ + struct pn532_uart_phy *pn532 = (struct pn532_uart_phy *) tty->disc_data; + + /* First make sure we're connected. */ + if (!pn532 || pn532->magic != PN532_MAGIC || pn532->tty != tty) + return; + + flush_workqueue(pn532->wq_open_tty); + destroy_workqueue(pn532->wq_open_tty); + pn533_unregister_device(pn532->priv); + + kfree_skb(pn532->recv_skb); + kfree(pn532); +} + +static int pn532_hangup(struct tty_struct *tty) +{ + pn532_close(tty); + return 0; +} + +/* Perform I/O control on an active PN532 line discipline channel. */ +static int pn532_ioctl(struct tty_struct *tty, struct file *file, + unsigned int cmd, unsigned long arg) +{ + struct pn532_uart_phy *pn532 = (struct pn532_uart_phy *) tty->disc_data; + unsigned int tmp; + + wait_for_completion(&pn532->init_done); + flush_workqueue(pn532->wq_open_tty); + /* First make sure we're connected. */ + if (!pn532 || pn532->magic != PN532_MAGIC) + return -EINVAL; + + switch (cmd) { + case SIOCGIFNAME: + if (!pn532->priv->nfc_dev) { + dev_err(tty->dev, "The device was not (successfully) connected before.\n"); + return -EINVAL; + } + tmp = strlen(nfc_device_name(pn532->priv->nfc_dev)) + 1; + if (copy_to_user((void __user *)arg, + nfc_device_name(pn532->priv->nfc_dev), tmp)) + return -EFAULT; + + return 0; + + case SIOCSIFHWADDR: + return -EINVAL; + + default: + return tty_mode_ioctl(tty, file, cmd, arg); + } +} + +/* + * scans the buffer if it contains a pn532 frame. It is not checked if the + * frame is really valid. This is later done with pn533_rx_frame_is_valid. + * This is useful for malformed or errornous transmitted frames. Adjusts the + * bufferposition where the frame starts, since pn533_recv_frame expects a + * well formed frame. + */ +static int pn532_uart_rx_is_frame(struct sk_buff *skb, struct tty_struct *tty) +{ + int i; + u16 frame_len; + struct pn533_std_frame *std; + struct pn533_ext_frame *ext; + + for (i = 0; i + PN533_STD_FRAME_ACK_SIZE <= skb->len; i++) { + std = (struct pn533_std_frame *)&skb->data[i]; + /* search start code */ + if (std->start_frame != cpu_to_be16(PN533_STD_FRAME_SOF)) + continue; + + /* frame type */ + switch (std->datalen) { + case PN533_FRAME_DATALEN_ACK: + dev_dbg(tty->dev, "ack frame"); + if (std->datalen_checksum == 0xff) { + skb_pull(skb, i); + return 1; + } + + break; + case PN533_FRAME_DATALEN_ERROR: + dev_dbg(tty->dev, "error frame"); + if ((std->datalen_checksum == 0xff) && + (skb->len >= + PN533_STD_ERROR_FRAME_SIZE)) { + skb_pull(skb, i); + return 1; + } + + break; + case PN533_FRAME_DATALEN_EXTENDED: + dev_dbg(tty->dev, "extended frame"); + ext = (struct pn533_ext_frame *)&skb->data[i]; + frame_len = ext->datalen; + if (skb->len >= frame_len + + sizeof(struct pn533_ext_frame) + + 2 /* CKS + Postamble */) { + skb_pull(skb, i); + return 1; + } + + break; + default: /* normal information frame */ + frame_len = std->datalen; + if (skb->len >= frame_len + + sizeof(struct pn533_std_frame) + + 2 /* CKS + Postamble */) { + skb_pull(skb, i); + return 1; + } + + break; + } + } + + return 0; +} + +static void pn532_receive_buf(struct tty_struct *tty, + const unsigned char *cp, char *fp, int count) +{ + struct pn532_uart_phy *dev = (struct pn532_uart_phy *)tty->disc_data; + + if (!dev) + return; + + del_timer(&dev->cmd_timeout); + while (count-- && (skb_end_offset(dev->recv_skb) > 1)) { + if (fp && *fp++) { + cp++; + continue; + } + + skb_put_u8(dev->recv_skb, *cp++); + if (!pn532_uart_rx_is_frame(dev->recv_skb, tty)) + continue; + + pn533_recv_frame(dev->priv, dev->recv_skb, 0); + dev->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL); + if (dev->recv_skb == NULL) + return; + } +} + +static void pn532_write_wakeup(struct tty_struct *tty) +{ + struct pn532_uart_phy *pn532 = (struct pn532_uart_phy *)tty->disc_data; + + if (!pn532 || pn532->magic != PN532_MAGIC) + return; + + clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags); +} + +static struct tty_ldisc_ops pn532_ldisc = { + .owner = THIS_MODULE, + .magic = TTY_LDISC_MAGIC, + .name = "pn532", + .open = pn532_open, + .close = pn532_close, + .hangup = pn532_hangup, + .ioctl = pn532_ioctl, + .receive_buf = pn532_receive_buf, + .write_wakeup = pn532_write_wakeup, +}; + +static int __init pn532_init(void) +{ + int ret; + + ret = tty_register_ldisc(N_PN532, &pn532_ldisc); + if (ret) + pr_err("pn532: can not register line discipline\n"); + + return ret; +} + +static void __exit pn532_exit(void) +{ + int ret; + + ret = tty_unregister_ldisc(N_PN532); + if (ret) + pr_err("pn532: can not unregister ldisc (err %d)\n", ret); +} + +module_init(pn532_init); +module_exit(pn532_exit); + +MODULE_ALIAS_LDISC(N_PN532); +MODULE_AUTHOR("Lars Poeschel <[email protected]>"); +MODULE_DESCRIPTION("PN532 UART driver ver " VERSION); +MODULE_VERSION(VERSION); +MODULE_LICENSE("GPL"); diff --git a/include/uapi/linux/tty.h b/include/uapi/linux/tty.h index 376cccf397be..0517b5354488 100644 --- a/include/uapi/linux/tty.h +++ b/include/uapi/linux/tty.h @@ -38,5 +38,6 @@ #define N_NCI 25 /* NFC NCI UART */ #define N_SPEAKUP 26 /* Speakup communication with synths */ #define N_NULL 27 /* Null ldisc used for error handling */ +#define N_PN532 28 /* NXP PN532 NFC chip */ #endif /* _UAPI_LINUX_TTY_H */ -- 2.19.1
