// SPDX-License-Identifier: GPL-2.0+ /* * Driver for NXP PN532 NFC Chip - UART transport layer * * Copyright (C) 2018 Lemonage Software GmbH * Author: Lars Pöschel * All rights reserved. */ #include #include #include #include #include #include #include #include "pn533.h" #define PN532_UART_SKB_BUFF_LEN (PN533_CMD_DATAEXCH_DATA_MAXLEN * 2) enum send_wakeup { PN532_SEND_NO_WAKEUP = 0, PN532_SEND_WAKEUP, PN532_SEND_LAST_WAKEUP, }; struct pn532_uart_phy { struct serdev_device *serdev; struct sk_buff *recv_skb; struct pn533 *priv; /* * send_wakeup variable is used to control if we need to send a wakeup * request to the pn532 chip prior to our actual command. There is a * little propability of a race condition. We decided to not mutex the * variable as the worst that could happen is, that we send a wakeup * to the chip that is already awake. This does not hurt. It is a * no-op to the chip. */ enum send_wakeup send_wakeup; struct timer_list cmd_timeout; struct sk_buff *cur_out_buf; }; static int pn532_uart_send_frame(struct pn533 *dev, struct sk_buff *out) { /* wakeup sequence and dummy bytes for waiting time */ static const u8 wakeup[] = { 0x55, 0x55, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; struct pn532_uart_phy *pn532 = dev->phy; int err; print_hex_dump_debug("PN532_uart TX: ", DUMP_PREFIX_NONE, 16, 1, out->data, out->len, false); pn532->cur_out_buf = out; if (pn532->send_wakeup) { err = serdev_device_write(pn532->serdev, wakeup, sizeof(wakeup), MAX_SCHEDULE_TIMEOUT); if (err < 0) return err; } if (pn532->send_wakeup == PN532_SEND_LAST_WAKEUP) pn532->send_wakeup = PN532_SEND_NO_WAKEUP; err = serdev_device_write(pn532->serdev, out->data, out->len, MAX_SCHEDULE_TIMEOUT); if (err < 0) return err; mod_timer(&pn532->cmd_timeout, HZ / 40 + jiffies); return 0; } static int pn532_uart_send_ack(struct pn533 *dev, gfp_t flags) { /* spec 7.1.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */ static const u8 ack[PN533_STD_FRAME_ACK_SIZE] = { 0x00, 0x00, 0xff, 0x00, 0xff, 0x00}; struct pn532_uart_phy *pn532 = dev->phy; int err; err = serdev_device_write(pn532->serdev, ack, sizeof(ack), MAX_SCHEDULE_TIMEOUT); if (err < 0) return err; 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 int pn532_dev_up(struct pn533 *dev) { struct pn532_uart_phy *pn532 = dev->phy; int ret = 0; ret = serdev_device_open(pn532->serdev); if (ret) return ret; pn532->send_wakeup = PN532_SEND_LAST_WAKEUP; return ret; } static int pn532_dev_down(struct pn533 *dev) { struct pn532_uart_phy *pn532 = dev->phy; serdev_device_close(pn532->serdev); pn532->send_wakeup = PN532_SEND_WAKEUP; return 0; } static const 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, .dev_up = pn532_dev_up, .dev_down = pn532_dev_down, }; 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); } /* * 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 pn533_std_frame *std; struct pn533_ext_frame *ext; u16 frame_len; int i; 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: if (std->datalen_checksum == 0xff) { skb_pull(skb, i); return 1; } break; case PN533_FRAME_DATALEN_ERROR: if ((std->datalen_checksum == 0xff) && (skb->len >= PN533_STD_ERROR_FRAME_SIZE)) { skb_pull(skb, i); return 1; } break; case PN533_FRAME_DATALEN_EXTENDED: ext = (struct pn533_ext_frame *)&skb->data[i]; frame_len = be16_to_cpu(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 size_t pn532_receive_buf(struct serdev_device *serdev, const u8 *data, size_t count) { struct pn532_uart_phy *dev = serdev_device_get_drvdata(serdev); size_t i; del_timer(&dev->cmd_timeout); for (i = 0; i < count; i++) { skb_put_u8(dev->recv_skb, *data++); if (!pn532_uart_rx_is_frame(dev->recv_skb)) 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) return 0; } return i; } static const struct serdev_device_ops pn532_serdev_ops = { .receive_buf = pn532_receive_buf, .write_wakeup = serdev_device_write_wakeup, }; static const struct of_device_id pn532_uart_of_match[] = { { .compatible = "nxp,pn532", }, {}, }; MODULE_DEVICE_TABLE(of, pn532_uart_of_match); static int pn532_uart_probe(struct serdev_device *serdev) { struct pn532_uart_phy *pn532; struct pn533 *priv; int err; err = -ENOMEM; pn532 = kzalloc(sizeof(*pn532), GFP_KERNEL); if (!pn532) goto err_exit; pn532->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL); if (!pn532->recv_skb) goto err_free; pn532->serdev = serdev; serdev_device_set_drvdata(serdev, pn532); serdev_device_set_client_ops(serdev, &pn532_serdev_ops); err = serdev_device_open(serdev); if (err) { dev_err(&serdev->dev, "Unable to open device\n"); goto err_skb; } err = serdev_device_set_baudrate(serdev, 115200); if (err != 115200) { err = -EINVAL; goto err_serdev; } serdev_device_set_flow_control(serdev, false); pn532->send_wakeup = PN532_SEND_WAKEUP; timer_setup(&pn532->cmd_timeout, pn532_cmd_timeout, 0); priv = pn53x_common_init(PN533_DEVICE_PN532_AUTOPOLL, PN533_PROTO_REQ_ACK_RESP, pn532, &uart_phy_ops, NULL, &pn532->serdev->dev); if (IS_ERR(priv)) { err = PTR_ERR(priv); goto err_serdev; } pn532->priv = priv; err = pn533_finalize_setup(pn532->priv); if (err) goto err_clean; serdev_device_close(serdev); err = pn53x_register_nfc(priv, PN533_NO_TYPE_B_PROTOCOLS, &serdev->dev); if (err) { pn53x_common_clean(pn532->priv); goto err_skb; } return err; err_clean: pn53x_common_clean(pn532->priv); err_serdev: serdev_device_close(serdev); err_skb: kfree_skb(pn532->recv_skb); err_free: kfree(pn532); err_exit: return err; } static void pn532_uart_remove(struct serdev_device *serdev) { struct pn532_uart_phy *pn532 = serdev_device_get_drvdata(serdev); pn53x_unregister_nfc(pn532->priv); serdev_device_close(serdev); pn53x_common_clean(pn532->priv); timer_shutdown_sync(&pn532->cmd_timeout); kfree_skb(pn532->recv_skb); kfree(pn532); } static struct serdev_device_driver pn532_uart_driver = { .probe = pn532_uart_probe, .remove = pn532_uart_remove, .driver = { .name = "pn532_uart", .of_match_table = pn532_uart_of_match, }, }; module_serdev_device_driver(pn532_uart_driver); MODULE_AUTHOR("Lars Pöschel "); MODULE_DESCRIPTION("PN532 UART driver"); MODULE_LICENSE("GPL");