Release 4.11 drivers/net/caif/caif_spi_slave.c
/*
* Copyright (C) ST-Ericsson AB 2010
* Author: Daniel Martensson
* License terms: GNU General Public License (GPL) version 2.
*/
#include <linux/module.h>
#include <linux/device.h>
#include <linux/platform_device.h>
#include <linux/string.h>
#include <linux/semaphore.h>
#include <linux/workqueue.h>
#include <linux/completion.h>
#include <linux/list.h>
#include <linux/interrupt.h>
#include <linux/dma-mapping.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/debugfs.h>
#include <net/caif/caif_spi.h>
#ifndef CONFIG_CAIF_SPI_SYNC
#define SPI_DATA_POS 0
static inline int forward_to_spi_cmd(struct cfspi *cfspi)
{
return cfspi->rx_cpck_len;
}
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#else
#define SPI_DATA_POS SPI_CMD_SZ
static inline int forward_to_spi_cmd(struct cfspi *cfspi)
{
return 0;
}
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#endif
int spi_frm_align = 2;
/*
* SPI padding options.
* Warning: must be a base of 2 (& operation used) and can not be zero !
*/
int spi_up_head_align = 1 << 1;
int spi_up_tail_align = 1 << 0;
int spi_down_head_align = 1 << 2;
int spi_down_tail_align = 1 << 1;
#ifdef CONFIG_DEBUG_FS
static inline void debugfs_store_prev(struct cfspi *cfspi)
{
/* Store previous command for debugging reasons.*/
cfspi->pcmd = cfspi->cmd;
/* Store previous transfer. */
cfspi->tx_ppck_len = cfspi->tx_cpck_len;
cfspi->rx_ppck_len = cfspi->rx_cpck_len;
}
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#else
static inline void debugfs_store_prev(struct cfspi *cfspi)
{
}
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#endif
void cfspi_xfer(struct work_struct *work)
{
struct cfspi *cfspi;
u8 *ptr = NULL;
unsigned long flags;
int ret;
cfspi = container_of(work, struct cfspi, work);
/* Initialize state. */
cfspi->cmd = SPI_CMD_EOT;
for (;;) {
cfspi_dbg_state(cfspi, CFSPI_STATE_WAITING);
/* Wait for master talk or transmit event. */
wait_event_interruptible(cfspi->wait,
test_bit(SPI_XFER, &cfspi->state) ||
test_bit(SPI_TERMINATE, &cfspi->state));
if (test_bit(SPI_TERMINATE, &cfspi->state))
return;
#if CFSPI_DBG_PREFILL
/* Prefill buffers for easier debugging. */
memset(cfspi->xfer.va_tx, 0xFF, SPI_DMA_BUF_LEN);
memset(cfspi->xfer.va_rx, 0xFF, SPI_DMA_BUF_LEN);
#endif /* CFSPI_DBG_PREFILL */
cfspi_dbg_state(cfspi, CFSPI_STATE_AWAKE);
/* Check whether we have a committed frame. */
if (cfspi->tx_cpck_len) {
int len;
cfspi_dbg_state(cfspi, CFSPI_STATE_FETCH_PKT);
/* Copy committed SPI frames after the SPI indication. */
ptr = (u8 *) cfspi->xfer.va_tx;
ptr += SPI_IND_SZ;
len = cfspi_xmitfrm(cfspi, ptr, cfspi->tx_cpck_len);
WARN_ON(len != cfspi->tx_cpck_len);
}
cfspi_dbg_state(cfspi, CFSPI_STATE_GET_NEXT);
/* Get length of next frame to commit. */
cfspi->tx_npck_len = cfspi_xmitlen(cfspi);
WARN_ON(cfspi->tx_npck_len > SPI_DMA_BUF_LEN);
/*
* Add indication and length at the beginning of the frame,
* using little endian.
*/
ptr = (u8 *) cfspi->xfer.va_tx;
*ptr++ = SPI_CMD_IND;
*ptr++ = (SPI_CMD_IND & 0xFF00) >> 8;
*ptr++ = cfspi->tx_npck_len & 0x00FF;
*ptr++ = (cfspi->tx_npck_len & 0xFF00) >> 8;
/* Calculate length of DMAs. */
cfspi->xfer.tx_dma_len = cfspi->tx_cpck_len + SPI_IND_SZ;
cfspi->xfer.rx_dma_len = cfspi->rx_cpck_len + SPI_CMD_SZ;
/* Add SPI TX frame alignment padding, if necessary. */
if (cfspi->tx_cpck_len &&
(cfspi->xfer.tx_dma_len % spi_frm_align)) {
cfspi->xfer.tx_dma_len += spi_frm_align -
(cfspi->xfer.tx_dma_len % spi_frm_align);
}
/* Add SPI RX frame alignment padding, if necessary. */
if (cfspi->rx_cpck_len &&
(cfspi->xfer.rx_dma_len % spi_frm_align)) {
cfspi->xfer.rx_dma_len += spi_frm_align -
(cfspi->xfer.rx_dma_len % spi_frm_align);
}
cfspi_dbg_state(cfspi, CFSPI_STATE_INIT_XFER);
/* Start transfer. */
ret = cfspi->dev->init_xfer(&cfspi->xfer, cfspi->dev);
WARN_ON(ret);
cfspi_dbg_state(cfspi, CFSPI_STATE_WAIT_ACTIVE);
/*
* TODO: We might be able to make an assumption if this is the
* first loop. Make sure that minimum toggle time is respected.
*/
udelay(MIN_TRANSITION_TIME_USEC);
cfspi_dbg_state(cfspi, CFSPI_STATE_SIG_ACTIVE);
/* Signal that we are ready to receive data. */
cfspi->dev->sig_xfer(true, cfspi->dev);
cfspi_dbg_state(cfspi, CFSPI_STATE_WAIT_XFER_DONE);
/* Wait for transfer completion. */
wait_for_completion(&cfspi->comp);
cfspi_dbg_state(cfspi, CFSPI_STATE_XFER_DONE);
if (cfspi->cmd == SPI_CMD_EOT) {
/*
* Clear the master talk bit. A xfer is always at
* least two bursts.
*/
clear_bit(SPI_SS_ON, &cfspi->state);
}
cfspi_dbg_state(cfspi, CFSPI_STATE_WAIT_INACTIVE);
/* Make sure that the minimum toggle time is respected. */
if (SPI_XFER_TIME_USEC(cfspi->xfer.tx_dma_len,
cfspi->dev->clk_mhz) <
MIN_TRANSITION_TIME_USEC) {
udelay(MIN_TRANSITION_TIME_USEC -
SPI_XFER_TIME_USEC
(cfspi->xfer.tx_dma_len, cfspi->dev->clk_mhz));
}
cfspi_dbg_state(cfspi, CFSPI_STATE_SIG_INACTIVE);
/* De-assert transfer signal. */
cfspi->dev->sig_xfer(false, cfspi->dev);
/* Check whether we received a CAIF packet. */
if (cfspi->rx_cpck_len) {
int len;
cfspi_dbg_state(cfspi, CFSPI_STATE_DELIVER_PKT);
/* Parse SPI frame. */
ptr = ((u8 *)(cfspi->xfer.va_rx + SPI_DATA_POS));
len = cfspi_rxfrm(cfspi, ptr, cfspi->rx_cpck_len);
WARN_ON(len != cfspi->rx_cpck_len);
}
/* Check the next SPI command and length. */
ptr = (u8 *) cfspi->xfer.va_rx;
ptr += forward_to_spi_cmd(cfspi);
cfspi->cmd = *ptr++;
cfspi->cmd |= ((*ptr++) << 8) & 0xFF00;
cfspi->rx_npck_len = *ptr++;
cfspi->rx_npck_len |= ((*ptr++) << 8) & 0xFF00;
WARN_ON(cfspi->rx_npck_len > SPI_DMA_BUF_LEN);
WARN_ON(cfspi->cmd > SPI_CMD_EOT);
debugfs_store_prev(cfspi);
/* Check whether the master issued an EOT command. */
if (cfspi->cmd == SPI_CMD_EOT) {
/* Reset state. */
cfspi->tx_cpck_len = 0;
cfspi->rx_cpck_len = 0;
} else {
/* Update state. */
cfspi->tx_cpck_len = cfspi->tx_npck_len;
cfspi->rx_cpck_len = cfspi->rx_npck_len;
}
/*
* Check whether we need to clear the xfer bit.
* Spin lock needed for packet insertion.
* Test and clear of different bits
* are not supported.
*/
spin_lock_irqsave(&cfspi->lock, flags);
if (cfspi->cmd == SPI_CMD_EOT && !cfspi_xmitlen(cfspi)
&& !test_bit(SPI_SS_ON, &cfspi->state))
clear_bit(SPI_XFER, &cfspi->state);
spin_unlock_irqrestore(&cfspi->lock, flags);
}
}
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struct platform_driver cfspi_spi_driver = {
.probe = cfspi_spi_probe,
.remove = cfspi_spi_remove,
.driver = {
.name = "cfspi_sspi",
.owner = THIS_MODULE,
},
};
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