// SPDX-License-Identifier: GPL-2.0+
/*
* Driver for NXP PN532 NFC Chip - UART transport layer
*
* Copyright (C) 2018 Lemonage Software GmbH
* Author: Lars Pöschel <[email protected]>
* All rights reserved.
*/
#include <linux/device.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/nfc.h>
#include <linux/netdevice.h>
#include <linux/of.h>
#include <linux/serdev.h>
#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 <[email protected]>");
MODULE_DESCRIPTION("PN532 UART driver");
MODULE_LICENSE("GPL");
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