diff options
Diffstat (limited to 'drivers/net/caif/caif_spi_slave.c')
| -rw-r--r-- | drivers/net/caif/caif_spi_slave.c | 254 |
1 files changed, 254 insertions, 0 deletions
diff --git a/drivers/net/caif/caif_spi_slave.c b/drivers/net/caif/caif_spi_slave.c new file mode 100644 index 000000000..39ba2f892 --- /dev/null +++ b/drivers/net/caif/caif_spi_slave.c @@ -0,0 +1,254 @@ +/* + * 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; +} +#else +#define SPI_DATA_POS SPI_CMD_SZ +static inline int forward_to_spi_cmd(struct cfspi *cfspi) +{ + return 0; +} +#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; +} +#else +static inline void debugfs_store_prev(struct cfspi *cfspi) +{ +} +#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); + } +} + +struct platform_driver cfspi_spi_driver = { + .probe = cfspi_spi_probe, + .remove = cfspi_spi_remove, + .driver = { + .name = "cfspi_sspi", + .owner = THIS_MODULE, + }, +}; |