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![Lars Poeschel](/assets/img/avatar_default.png)
Change dev_up and dev_down functions of struct pn533_phy_ops to return
int. This way the pn533 core can report errors in the phy layer to upper
layers.
The only user of this is currently uart.c and it is changed to report
the error of a possibly failing call to serdev_device_open.
Reported-by: coverity-bot <keescook+coverity-bot@chromium.org>
Addresses-Coverity-ID: 1487395 ("Error handling issues")
Fixes: c656aa4c27
("nfc: pn533: add UART phy driver")
Signed-off-by: Lars Poeschel <poeschel@lemonage.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
330 lines
7.9 KiB
C
330 lines
7.9 KiB
C
// SPDX-License-Identifier: GPL-2.0+
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/*
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* Driver for NXP PN532 NFC Chip - UART transport layer
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*
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* Copyright (C) 2018 Lemonage Software GmbH
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* Author: Lars Pöschel <poeschel@lemonage.de>
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* All rights reserved.
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*/
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#include <linux/device.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/nfc.h>
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#include <linux/netdevice.h>
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#include <linux/of.h>
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#include <linux/serdev.h>
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#include "pn533.h"
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#define PN532_UART_SKB_BUFF_LEN (PN533_CMD_DATAEXCH_DATA_MAXLEN * 2)
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enum send_wakeup {
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PN532_SEND_NO_WAKEUP = 0,
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PN532_SEND_WAKEUP,
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PN532_SEND_LAST_WAKEUP,
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};
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struct pn532_uart_phy {
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struct serdev_device *serdev;
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struct sk_buff *recv_skb;
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struct pn533 *priv;
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/*
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* send_wakeup variable is used to control if we need to send a wakeup
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* request to the pn532 chip prior to our actual command. There is a
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* little propability of a race condition. We decided to not mutex the
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* variable as the worst that could happen is, that we send a wakeup
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* to the chip that is already awake. This does not hurt. It is a
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* no-op to the chip.
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*/
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enum send_wakeup send_wakeup;
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struct timer_list cmd_timeout;
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struct sk_buff *cur_out_buf;
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};
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static int pn532_uart_send_frame(struct pn533 *dev,
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struct sk_buff *out)
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{
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/* wakeup sequence and dummy bytes for waiting time */
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static const u8 wakeup[] = {
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0x55, 0x55, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
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0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
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struct pn532_uart_phy *pn532 = dev->phy;
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int err;
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print_hex_dump_debug("PN532_uart TX: ", DUMP_PREFIX_NONE, 16, 1,
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out->data, out->len, false);
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pn532->cur_out_buf = out;
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if (pn532->send_wakeup) {
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err = serdev_device_write(pn532->serdev,
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wakeup, sizeof(wakeup),
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MAX_SCHEDULE_TIMEOUT);
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if (err < 0)
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return err;
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}
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if (pn532->send_wakeup == PN532_SEND_LAST_WAKEUP)
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pn532->send_wakeup = PN532_SEND_NO_WAKEUP;
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err = serdev_device_write(pn532->serdev, out->data, out->len,
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MAX_SCHEDULE_TIMEOUT);
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if (err < 0)
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return err;
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mod_timer(&pn532->cmd_timeout, HZ / 40 + jiffies);
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return 0;
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}
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static int pn532_uart_send_ack(struct pn533 *dev, gfp_t flags)
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{
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/* spec 7.1.1.3: Preamble, SoPC (2), ACK Code (2), Postamble */
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static const u8 ack[PN533_STD_FRAME_ACK_SIZE] = {
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0x00, 0x00, 0xff, 0x00, 0xff, 0x00};
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struct pn532_uart_phy *pn532 = dev->phy;
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int err;
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err = serdev_device_write(pn532->serdev, ack, sizeof(ack),
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MAX_SCHEDULE_TIMEOUT);
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if (err < 0)
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return err;
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return 0;
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}
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static void pn532_uart_abort_cmd(struct pn533 *dev, gfp_t flags)
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{
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/* An ack will cancel the last issued command */
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pn532_uart_send_ack(dev, flags);
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/* schedule cmd_complete_work to finish current command execution */
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pn533_recv_frame(dev, NULL, -ENOENT);
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}
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static int pn532_dev_up(struct pn533 *dev)
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{
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struct pn532_uart_phy *pn532 = dev->phy;
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int ret = 0;
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ret = serdev_device_open(pn532->serdev);
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if (ret)
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return ret;
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pn532->send_wakeup = PN532_SEND_LAST_WAKEUP;
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return ret;
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}
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static int pn532_dev_down(struct pn533 *dev)
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{
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struct pn532_uart_phy *pn532 = dev->phy;
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serdev_device_close(pn532->serdev);
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pn532->send_wakeup = PN532_SEND_WAKEUP;
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return 0;
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}
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static struct pn533_phy_ops uart_phy_ops = {
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.send_frame = pn532_uart_send_frame,
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.send_ack = pn532_uart_send_ack,
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.abort_cmd = pn532_uart_abort_cmd,
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.dev_up = pn532_dev_up,
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.dev_down = pn532_dev_down,
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};
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static void pn532_cmd_timeout(struct timer_list *t)
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{
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struct pn532_uart_phy *dev = from_timer(dev, t, cmd_timeout);
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pn532_uart_send_frame(dev->priv, dev->cur_out_buf);
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}
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/*
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* scans the buffer if it contains a pn532 frame. It is not checked if the
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* frame is really valid. This is later done with pn533_rx_frame_is_valid.
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* This is useful for malformed or errornous transmitted frames. Adjusts the
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* bufferposition where the frame starts, since pn533_recv_frame expects a
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* well formed frame.
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*/
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static int pn532_uart_rx_is_frame(struct sk_buff *skb)
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{
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struct pn533_std_frame *std;
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struct pn533_ext_frame *ext;
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u16 frame_len;
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int i;
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for (i = 0; i + PN533_STD_FRAME_ACK_SIZE <= skb->len; i++) {
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std = (struct pn533_std_frame *)&skb->data[i];
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/* search start code */
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if (std->start_frame != cpu_to_be16(PN533_STD_FRAME_SOF))
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continue;
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/* frame type */
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switch (std->datalen) {
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case PN533_FRAME_DATALEN_ACK:
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if (std->datalen_checksum == 0xff) {
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skb_pull(skb, i);
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return 1;
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}
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break;
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case PN533_FRAME_DATALEN_ERROR:
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if ((std->datalen_checksum == 0xff) &&
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(skb->len >=
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PN533_STD_ERROR_FRAME_SIZE)) {
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skb_pull(skb, i);
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return 1;
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}
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break;
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case PN533_FRAME_DATALEN_EXTENDED:
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ext = (struct pn533_ext_frame *)&skb->data[i];
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frame_len = be16_to_cpu(ext->datalen);
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if (skb->len >= frame_len +
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sizeof(struct pn533_ext_frame) +
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2 /* CKS + Postamble */) {
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skb_pull(skb, i);
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return 1;
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}
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break;
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default: /* normal information frame */
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frame_len = std->datalen;
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if (skb->len >= frame_len +
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sizeof(struct pn533_std_frame) +
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2 /* CKS + Postamble */) {
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skb_pull(skb, i);
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return 1;
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}
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break;
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}
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}
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return 0;
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}
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static int pn532_receive_buf(struct serdev_device *serdev,
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const unsigned char *data, size_t count)
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{
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struct pn532_uart_phy *dev = serdev_device_get_drvdata(serdev);
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size_t i;
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del_timer(&dev->cmd_timeout);
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for (i = 0; i < count; i++) {
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skb_put_u8(dev->recv_skb, *data++);
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if (!pn532_uart_rx_is_frame(dev->recv_skb))
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continue;
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pn533_recv_frame(dev->priv, dev->recv_skb, 0);
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dev->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL);
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if (!dev->recv_skb)
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return 0;
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}
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return i;
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}
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static struct serdev_device_ops pn532_serdev_ops = {
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.receive_buf = pn532_receive_buf,
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.write_wakeup = serdev_device_write_wakeup,
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};
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static const struct of_device_id pn532_uart_of_match[] = {
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{ .compatible = "nxp,pn532", },
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{},
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};
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MODULE_DEVICE_TABLE(of, pn532_uart_of_match);
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static int pn532_uart_probe(struct serdev_device *serdev)
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{
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struct pn532_uart_phy *pn532;
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struct pn533 *priv;
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int err;
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err = -ENOMEM;
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pn532 = kzalloc(sizeof(*pn532), GFP_KERNEL);
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if (!pn532)
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goto err_exit;
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pn532->recv_skb = alloc_skb(PN532_UART_SKB_BUFF_LEN, GFP_KERNEL);
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if (!pn532->recv_skb)
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goto err_free;
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pn532->serdev = serdev;
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serdev_device_set_drvdata(serdev, pn532);
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serdev_device_set_client_ops(serdev, &pn532_serdev_ops);
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err = serdev_device_open(serdev);
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if (err) {
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dev_err(&serdev->dev, "Unable to open device\n");
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goto err_skb;
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}
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err = serdev_device_set_baudrate(serdev, 115200);
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if (err != 115200) {
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err = -EINVAL;
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goto err_serdev;
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}
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serdev_device_set_flow_control(serdev, false);
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pn532->send_wakeup = PN532_SEND_WAKEUP;
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timer_setup(&pn532->cmd_timeout, pn532_cmd_timeout, 0);
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priv = pn53x_common_init(PN533_DEVICE_PN532_AUTOPOLL,
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PN533_PROTO_REQ_ACK_RESP,
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pn532, &uart_phy_ops, NULL,
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&pn532->serdev->dev);
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if (IS_ERR(priv)) {
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err = PTR_ERR(priv);
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goto err_serdev;
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}
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pn532->priv = priv;
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err = pn533_finalize_setup(pn532->priv);
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if (err)
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goto err_clean;
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serdev_device_close(serdev);
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err = pn53x_register_nfc(priv, PN533_NO_TYPE_B_PROTOCOLS, &serdev->dev);
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if (err) {
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pn53x_common_clean(pn532->priv);
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goto err_skb;
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}
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return err;
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err_clean:
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pn53x_common_clean(pn532->priv);
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err_serdev:
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serdev_device_close(serdev);
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err_skb:
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kfree_skb(pn532->recv_skb);
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err_free:
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kfree(pn532);
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err_exit:
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return err;
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}
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static void pn532_uart_remove(struct serdev_device *serdev)
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{
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struct pn532_uart_phy *pn532 = serdev_device_get_drvdata(serdev);
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pn53x_unregister_nfc(pn532->priv);
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serdev_device_close(serdev);
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pn53x_common_clean(pn532->priv);
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kfree_skb(pn532->recv_skb);
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kfree(pn532);
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}
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static struct serdev_device_driver pn532_uart_driver = {
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.probe = pn532_uart_probe,
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.remove = pn532_uart_remove,
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.driver = {
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.name = "pn532_uart",
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.of_match_table = of_match_ptr(pn532_uart_of_match),
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},
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};
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module_serdev_device_driver(pn532_uart_driver);
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MODULE_AUTHOR("Lars Pöschel <poeschel@lemonage.de>");
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MODULE_DESCRIPTION("PN532 UART driver");
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MODULE_LICENSE("GPL");
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