Orange Pi5 kernel

// SPDX-License-Identifier: GPL-2.0-only
/*
 * Copyright (C) 2013  Intel Corporation. All rights reserved.
 */
 
#define pr_fmt(fmt) "nci_spi: %s: " fmt, __func__
 
#include <linux/module.h>
 
#include <linux/export.h>
#include <linux/spi/spi.h>
#include <linux/crc-ccitt.h>
#include <net/nfc/nci_core.h>
 
#define NCI_SPI_ACK_SHIFT		6
#define NCI_SPI_MSB_PAYLOAD_MASK	0x3F
 
#define NCI_SPI_SEND_TIMEOUT	(NCI_CMD_TIMEOUT > NCI_DATA_TIMEOUT ? \
<------><------><------><------><------>NCI_CMD_TIMEOUT : NCI_DATA_TIMEOUT)
 
#define NCI_SPI_DIRECT_WRITE	0x01
#define NCI_SPI_DIRECT_READ	0x02
 
#define ACKNOWLEDGE_NONE	0
#define ACKNOWLEDGE_ACK		1
#define ACKNOWLEDGE_NACK	2
 
#define CRC_INIT		0xFFFF
 
static int __nci_spi_send(struct nci_spi *nspi, struct sk_buff *skb,
<------><------><------>  int cs_change)
{
<------>struct spi_message m;
<------>struct spi_transfer t;
 
<------>memset(&t, 0, sizeof(struct spi_transfer));
<------>/* a NULL skb means we just want the SPI chip select line to raise */
<------>if (skb) {
<------><------>t.tx_buf = skb->data;
<------><------>t.len = skb->len;
<------>} else {
<------><------>/* still set tx_buf non NULL to make the driver happy */
<------><------>t.tx_buf = &t;
<------><------>t.len = 0;
<------>}
<------>t.cs_change = cs_change;
<------>t.delay.value = nspi->xfer_udelay;
<------>t.delay.unit = SPI_DELAY_UNIT_USECS;
<------>t.speed_hz = nspi->xfer_speed_hz;
 
<------>spi_message_init(&m);
<------>spi_message_add_tail(&t, &m);
 
<------>return spi_sync(nspi->spi, &m);
}
 
int nci_spi_send(struct nci_spi *nspi,
<------><------> struct completion *write_handshake_completion,
<------><------> struct sk_buff *skb)
{
<------>unsigned int payload_len = skb->len;
<------>unsigned char *hdr;
<------>int ret;
<------>long completion_rc;
 
<------>/* add the NCI SPI header to the start of the buffer */
<------>hdr = skb_push(skb, NCI_SPI_HDR_LEN);
<------>hdr[0] = NCI_SPI_DIRECT_WRITE;
<------>hdr[1] = nspi->acknowledge_mode;
<------>hdr[2] = payload_len >> 8;
<------>hdr[3] = payload_len & 0xFF;
 
<------>if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
<------><------>u16 crc;
 
<------><------>crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
<------><------>skb_put_u8(skb, crc >> 8);
<------><------>skb_put_u8(skb, crc & 0xFF);
<------>}
 
<------>if (write_handshake_completion)	{
<------><------>/* Trick SPI driver to raise chip select */
<------><------>ret = __nci_spi_send(nspi, NULL, 1);
<------><------>if (ret)
<------><------><------>goto done;
 
<------><------>/* wait for NFC chip hardware handshake to complete */
<------><------>if (wait_for_completion_timeout(write_handshake_completion,
<------><------><------><------><------><------>msecs_to_jiffies(1000)) == 0) {
<------><------><------>ret = -ETIME;
<------><------><------>goto done;
<------><------>}
<------>}
 
<------>ret = __nci_spi_send(nspi, skb, 0);
<------>if (ret != 0 || nspi->acknowledge_mode == NCI_SPI_CRC_DISABLED)
<------><------>goto done;
 
<------>reinit_completion(&nspi->req_completion);
<------>completion_rc =	wait_for_completion_interruptible_timeout(
<------><------><------><------><------><------><------>&nspi->req_completion,
<------><------><------><------><------><------><------>NCI_SPI_SEND_TIMEOUT);
 
<------>if (completion_rc <= 0 || nspi->req_result == ACKNOWLEDGE_NACK)
<------><------>ret = -EIO;
 
done:
<------>kfree_skb(skb);
 
<------>return ret;
}
EXPORT_SYMBOL_GPL(nci_spi_send);
 
/* ---- Interface to NCI SPI drivers ---- */
 
/**
 * nci_spi_allocate_spi - allocate a new nci spi
 *
 * @spi: SPI device
 * @acknowledge_mode: Acknowledge mode used by the NFC device
 * @delay: delay between transactions in us
 * @ndev: nci dev to send incoming nci frames to
 */
struct nci_spi *nci_spi_allocate_spi(struct spi_device *spi,
<------><------><------><------>     u8 acknowledge_mode, unsigned int delay,
<------><------><------><------>     struct nci_dev *ndev)
{
<------>struct nci_spi *nspi;
 
<------>nspi = devm_kzalloc(&spi->dev, sizeof(struct nci_spi), GFP_KERNEL);
<------>if (!nspi)
<------><------>return NULL;
 
<------>nspi->acknowledge_mode = acknowledge_mode;
<------>nspi->xfer_udelay = delay;
<------>/* Use controller max SPI speed by default */
<------>nspi->xfer_speed_hz = 0;
<------>nspi->spi = spi;
<------>nspi->ndev = ndev;
<------>init_completion(&nspi->req_completion);
 
<------>return nspi;
}
EXPORT_SYMBOL_GPL(nci_spi_allocate_spi);
 
static int send_acknowledge(struct nci_spi *nspi, u8 acknowledge)
{
<------>struct sk_buff *skb;
<------>unsigned char *hdr;
<------>u16 crc;
<------>int ret;
 
<------>skb = nci_skb_alloc(nspi->ndev, 0, GFP_KERNEL);
 
<------>/* add the NCI SPI header to the start of the buffer */
<------>hdr = skb_push(skb, NCI_SPI_HDR_LEN);
<------>hdr[0] = NCI_SPI_DIRECT_WRITE;
<------>hdr[1] = NCI_SPI_CRC_ENABLED;
<------>hdr[2] = acknowledge << NCI_SPI_ACK_SHIFT;
<------>hdr[3] = 0;
 
<------>crc = crc_ccitt(CRC_INIT, skb->data, skb->len);
<------>skb_put_u8(skb, crc >> 8);
<------>skb_put_u8(skb, crc & 0xFF);
 
<------>ret = __nci_spi_send(nspi, skb, 0);
 
<------>kfree_skb(skb);
 
<------>return ret;
}
 
static struct sk_buff *__nci_spi_read(struct nci_spi *nspi)
{
<------>struct sk_buff *skb;
<------>struct spi_message m;
<------>unsigned char req[2], resp_hdr[2];
<------>struct spi_transfer tx, rx;
<------>unsigned short rx_len = 0;
<------>int ret;
 
<------>spi_message_init(&m);
 
<------>memset(&tx, 0, sizeof(struct spi_transfer));
<------>req[0] = NCI_SPI_DIRECT_READ;
<------>req[1] = nspi->acknowledge_mode;
<------>tx.tx_buf = req;
<------>tx.len = 2;
<------>tx.cs_change = 0;
<------>tx.speed_hz = nspi->xfer_speed_hz;
<------>spi_message_add_tail(&tx, &m);
 
<------>memset(&rx, 0, sizeof(struct spi_transfer));
<------>rx.rx_buf = resp_hdr;
<------>rx.len = 2;
<------>rx.cs_change = 1;
<------>rx.speed_hz = nspi->xfer_speed_hz;
<------>spi_message_add_tail(&rx, &m);
 
<------>ret = spi_sync(nspi->spi, &m);
<------>if (ret)
<------><------>return NULL;
 
<------>if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED)
<------><------>rx_len = ((resp_hdr[0] & NCI_SPI_MSB_PAYLOAD_MASK) << 8) +
<------><------><------><------>resp_hdr[1] + NCI_SPI_CRC_LEN;
<------>else
<------><------>rx_len = (resp_hdr[0] << 8) | resp_hdr[1];
 
<------>skb = nci_skb_alloc(nspi->ndev, rx_len, GFP_KERNEL);
<------>if (!skb)
<------><------>return NULL;
 
<------>spi_message_init(&m);
 
<------>memset(&rx, 0, sizeof(struct spi_transfer));
<------>rx.rx_buf = skb_put(skb, rx_len);
<------>rx.len = rx_len;
<------>rx.cs_change = 0;
<------>rx.delay.value = nspi->xfer_udelay;
<------>rx.delay.unit = SPI_DELAY_UNIT_USECS;
<------>rx.speed_hz = nspi->xfer_speed_hz;
<------>spi_message_add_tail(&rx, &m);
 
<------>ret = spi_sync(nspi->spi, &m);
<------>if (ret)
<------><------>goto receive_error;
 
<------>if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
<------><------>*(u8 *)skb_push(skb, 1) = resp_hdr[1];
<------><------>*(u8 *)skb_push(skb, 1) = resp_hdr[0];
<------>}
 
<------>return skb;
 
receive_error:
<------>kfree_skb(skb);
 
<------>return NULL;
}
 
static int nci_spi_check_crc(struct sk_buff *skb)
{
<------>u16 crc_data = (skb->data[skb->len - 2] << 8) |
<------><------><------>skb->data[skb->len - 1];
<------>int ret;
 
<------>ret = (crc_ccitt(CRC_INIT, skb->data, skb->len - NCI_SPI_CRC_LEN)
<------><------><------>== crc_data);
 
<------>skb_trim(skb, skb->len - NCI_SPI_CRC_LEN);
 
<------>return ret;
}
 
static u8 nci_spi_get_ack(struct sk_buff *skb)
{
<------>u8 ret;
 
<------>ret = skb->data[0] >> NCI_SPI_ACK_SHIFT;
 
<------>/* Remove NFCC part of the header: ACK, NACK and MSB payload len */
<------>skb_pull(skb, 2);
 
<------>return ret;
}
 
/**
 * nci_spi_read - read frame from NCI SPI drivers
 *
 * @nspi: The nci spi
 * Context: can sleep
 *
 * This call may only be used from a context that may sleep.  The sleep
 * is non-interruptible, and has no timeout.
 *
 * It returns an allocated skb containing the frame on success, or NULL.
 */
struct sk_buff *nci_spi_read(struct nci_spi *nspi)
{
<------>struct sk_buff *skb;
 
<------>/* Retrieve frame from SPI */
<------>skb = __nci_spi_read(nspi);
<------>if (!skb)
<------><------>goto done;
 
<------>if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED) {
<------><------>if (!nci_spi_check_crc(skb)) {
<------><------><------>send_acknowledge(nspi, ACKNOWLEDGE_NACK);
<------><------><------>goto done;
<------><------>}
 
<------><------>/* In case of acknowledged mode: if ACK or NACK received,
<------><------> * unblock completion of latest frame sent.
<------><------> */
<------><------>nspi->req_result = nci_spi_get_ack(skb);
<------><------>if (nspi->req_result)
<------><------><------>complete(&nspi->req_completion);
<------>}
 
<------>/* If there is no payload (ACK/NACK only frame),
<------> * free the socket buffer
<------> */
<------>if (!skb->len) {
<------><------>kfree_skb(skb);
<------><------>skb = NULL;
<------><------>goto done;
<------>}
 
<------>if (nspi->acknowledge_mode == NCI_SPI_CRC_ENABLED)
<------><------>send_acknowledge(nspi, ACKNOWLEDGE_ACK);
 
done:
 
<------>return skb;
}
EXPORT_SYMBOL_GPL(nci_spi_read);
 
MODULE_LICENSE("GPL");