/* * Blackfin On-Chip SPI Driver * * Copyright 2004-2010 Analog Devices Inc. * * Enter bugs at http://blackfin.uclinux.org/ * * Licensed under the GPL-2 or later. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DRV_NAME "bfin-spi" #define DRV_AUTHOR "Bryan Wu, Luke Yang" #define DRV_DESC "Blackfin on-chip SPI Controller Driver" #define DRV_VERSION "1.0" MODULE_AUTHOR(DRV_AUTHOR); MODULE_DESCRIPTION(DRV_DESC); MODULE_LICENSE("GPL"); #define START_STATE ((void *)0) #define RUNNING_STATE ((void *)1) #define DONE_STATE ((void *)2) #define ERROR_STATE ((void *)-1) struct bfin_spi_master_data; struct bfin_spi_transfer_ops { void (*write) (struct bfin_spi_master_data *); void (*read) (struct bfin_spi_master_data *); void (*duplex) (struct bfin_spi_master_data *); }; struct bfin_spi_master_data { /* Driver model hookup */ struct platform_device *pdev; /* SPI framework hookup */ struct spi_master *master; /* Regs base of SPI controller */ void __iomem *regs_base; /* Pin request list */ u16 *pin_req; /* BFIN hookup */ struct bfin5xx_spi_master *master_info; /* Driver message queue */ struct workqueue_struct *workqueue; struct work_struct pump_messages; spinlock_t lock; struct list_head queue; int busy; bool running; /* Message Transfer pump */ struct tasklet_struct pump_transfers; /* Current message transfer state info */ struct spi_message *cur_msg; struct spi_transfer *cur_transfer; struct bfin_spi_slave_data *cur_chip; size_t len_in_bytes; size_t len; void *tx; void *tx_end; void *rx; void *rx_end; /* DMA stuffs */ int dma_channel; int dma_mapped; int dma_requested; dma_addr_t rx_dma; dma_addr_t tx_dma; int irq_requested; int spi_irq; size_t rx_map_len; size_t tx_map_len; u8 n_bytes; u16 ctrl_reg; u16 flag_reg; int cs_change; const struct bfin_spi_transfer_ops *ops; }; struct bfin_spi_slave_data { u16 ctl_reg; u16 baud; u16 flag; u8 chip_select_num; u8 enable_dma; u16 cs_chg_udelay; /* Some devices require > 255usec delay */ u32 cs_gpio; u16 idle_tx_val; u8 pio_interrupt; /* use spi data irq */ const struct bfin_spi_transfer_ops *ops; }; #define DEFINE_SPI_REG(reg, off) \ static inline u16 read_##reg(struct bfin_spi_master_data *drv_data) \ { return bfin_read16(drv_data->regs_base + off); } \ static inline void write_##reg(struct bfin_spi_master_data *drv_data, u16 v) \ { bfin_write16(drv_data->regs_base + off, v); } DEFINE_SPI_REG(CTRL, 0x00) DEFINE_SPI_REG(FLAG, 0x04) DEFINE_SPI_REG(STAT, 0x08) DEFINE_SPI_REG(TDBR, 0x0C) DEFINE_SPI_REG(RDBR, 0x10) DEFINE_SPI_REG(BAUD, 0x14) DEFINE_SPI_REG(SHAW, 0x18) static void bfin_spi_enable(struct bfin_spi_master_data *drv_data) { u16 cr; cr = read_CTRL(drv_data); write_CTRL(drv_data, (cr | BIT_CTL_ENABLE)); } static void bfin_spi_disable(struct bfin_spi_master_data *drv_data) { u16 cr; cr = read_CTRL(drv_data); write_CTRL(drv_data, (cr & (~BIT_CTL_ENABLE))); } /* Caculate the SPI_BAUD register value based on input HZ */ static u16 hz_to_spi_baud(u32 speed_hz) { u_long sclk = get_sclk(); u16 spi_baud = (sclk / (2 * speed_hz)); if ((sclk % (2 * speed_hz)) > 0) spi_baud++; if (spi_baud < MIN_SPI_BAUD_VAL) spi_baud = MIN_SPI_BAUD_VAL; return spi_baud; } static int bfin_spi_flush(struct bfin_spi_master_data *drv_data) { unsigned long limit = loops_per_jiffy << 1; /* wait for stop and clear stat */ while (!(read_STAT(drv_data) & BIT_STAT_SPIF) && --limit) cpu_relax(); write_STAT(drv_data, BIT_STAT_CLR); return limit; } /* Chip select operation functions for cs_change flag */ static void bfin_spi_cs_active(struct bfin_spi_master_data *drv_data, struct bfin_spi_slave_data *chip) { if (likely(chip->chip_select_num < MAX_CTRL_CS)) { u16 flag = read_FLAG(drv_data); flag &= ~chip->flag; write_FLAG(drv_data, flag); } else { gpio_set_value(chip->cs_gpio, 0); } } static void bfin_spi_cs_deactive(struct bfin_spi_master_data *drv_data, struct bfin_spi_slave_data *chip) { if (likely(chip->chip_select_num < MAX_CTRL_CS)) { u16 flag = read_FLAG(drv_data); flag |= chip->flag; write_FLAG(drv_data, flag); } else { gpio_set_value(chip->cs_gpio, 1); } /* Move delay here for consistency */ if (chip->cs_chg_udelay) udelay(chip->cs_chg_udelay); } /* enable or disable the pin muxed by GPIO and SPI CS to work as SPI CS */ static inline void bfin_spi_cs_enable(struct bfin_spi_master_data *drv_data, struct bfin_spi_slave_data *chip) { if (chip->chip_select_num < MAX_CTRL_CS) { u16 flag = read_FLAG(drv_data); flag |= (chip->flag >> 8); write_FLAG(drv_data, flag); } } static inline void bfin_spi_cs_disable(struct bfin_spi_master_data *drv_data, struct bfin_spi_slave_data *chip) { if (chip->chip_select_num < MAX_CTRL_CS) { u16 flag = read_FLAG(drv_data); flag &= ~(chip->flag >> 8); write_FLAG(drv_data, flag); } } /* stop controller and re-config current chip*/ static void bfin_spi_restore_state(struct bfin_spi_master_data *drv_data) { struct bfin_spi_slave_data *chip = drv_data->cur_chip; /* Clear status and disable clock */ write_STAT(drv_data, BIT_STAT_CLR); bfin_spi_disable(drv_data); dev_dbg(&drv_data->pdev->dev, "restoring spi ctl state\n"); SSYNC(); /* Load the registers */ write_CTRL(drv_data, chip->ctl_reg); write_BAUD(drv_data, chip->baud); bfin_spi_enable(drv_data); bfin_spi_cs_active(drv_data, chip); } /* used to kick off transfer in rx mode and read unwanted RX data */ static inline void bfin_spi_dummy_read(struct bfin_spi_master_data *drv_data) { (void) read_RDBR(drv_data); } static void bfin_spi_u8_writer(struct bfin_spi_master_data *drv_data) { /* clear RXS (we check for RXS inside the loop) */ bfin_spi_dummy_read(drv_data); while (drv_data->tx < drv_data->tx_end) { write_TDBR(drv_data, (*(u8 *) (drv_data->tx++))); /* wait until transfer finished. checking SPIF or TXS may not guarantee transfer completion */ while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); /* discard RX data and clear RXS */ bfin_spi_dummy_read(drv_data); } } static void bfin_spi_u8_reader(struct bfin_spi_master_data *drv_data) { u16 tx_val = drv_data->cur_chip->idle_tx_val; /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); while (drv_data->rx < drv_data->rx_end) { write_TDBR(drv_data, tx_val); while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); *(u8 *) (drv_data->rx++) = read_RDBR(drv_data); } } static void bfin_spi_u8_duplex(struct bfin_spi_master_data *drv_data) { /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); while (drv_data->rx < drv_data->rx_end) { write_TDBR(drv_data, (*(u8 *) (drv_data->tx++))); while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); *(u8 *) (drv_data->rx++) = read_RDBR(drv_data); } } static const struct bfin_spi_transfer_ops bfin_bfin_spi_transfer_ops_u8 = { .write = bfin_spi_u8_writer, .read = bfin_spi_u8_reader, .duplex = bfin_spi_u8_duplex, }; static void bfin_spi_u16_writer(struct bfin_spi_master_data *drv_data) { /* clear RXS (we check for RXS inside the loop) */ bfin_spi_dummy_read(drv_data); while (drv_data->tx < drv_data->tx_end) { write_TDBR(drv_data, (*(u16 *) (drv_data->tx))); drv_data->tx += 2; /* wait until transfer finished. checking SPIF or TXS may not guarantee transfer completion */ while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); /* discard RX data and clear RXS */ bfin_spi_dummy_read(drv_data); } } static void bfin_spi_u16_reader(struct bfin_spi_master_data *drv_data) { u16 tx_val = drv_data->cur_chip->idle_tx_val; /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); while (drv_data->rx < drv_data->rx_end) { write_TDBR(drv_data, tx_val); while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); *(u16 *) (drv_data->rx) = read_RDBR(drv_data); drv_data->rx += 2; } } static void bfin_spi_u16_duplex(struct bfin_spi_master_data *drv_data) { /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); while (drv_data->rx < drv_data->rx_end) { write_TDBR(drv_data, (*(u16 *) (drv_data->tx))); drv_data->tx += 2; while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); *(u16 *) (drv_data->rx) = read_RDBR(drv_data); drv_data->rx += 2; } } static const struct bfin_spi_transfer_ops bfin_bfin_spi_transfer_ops_u16 = { .write = bfin_spi_u16_writer, .read = bfin_spi_u16_reader, .duplex = bfin_spi_u16_duplex, }; /* test if there is more transfer to be done */ static void *bfin_spi_next_transfer(struct bfin_spi_master_data *drv_data) { struct spi_message *msg = drv_data->cur_msg; struct spi_transfer *trans = drv_data->cur_transfer; /* Move to next transfer */ if (trans->transfer_list.next != &msg->transfers) { drv_data->cur_transfer = list_entry(trans->transfer_list.next, struct spi_transfer, transfer_list); return RUNNING_STATE; } else return DONE_STATE; } /* * caller already set message->status; * dma and pio irqs are blocked give finished message back */ static void bfin_spi_giveback(struct bfin_spi_master_data *drv_data) { struct bfin_spi_slave_data *chip = drv_data->cur_chip; struct spi_transfer *last_transfer; unsigned long flags; struct spi_message *msg; spin_lock_irqsave(&drv_data->lock, flags); msg = drv_data->cur_msg; drv_data->cur_msg = NULL; drv_data->cur_transfer = NULL; drv_data->cur_chip = NULL; queue_work(drv_data->workqueue, &drv_data->pump_messages); spin_unlock_irqrestore(&drv_data->lock, flags); last_transfer = list_entry(msg->transfers.prev, struct spi_transfer, transfer_list); msg->state = NULL; if (!drv_data->cs_change) bfin_spi_cs_deactive(drv_data, chip); /* Not stop spi in autobuffer mode */ if (drv_data->tx_dma != 0xFFFF) bfin_spi_disable(drv_data); if (msg->complete) msg->complete(msg->context); } /* spi data irq handler */ static irqreturn_t bfin_spi_pio_irq_handler(int irq, void *dev_id) { struct bfin_spi_master_data *drv_data = dev_id; struct bfin_spi_slave_data *chip = drv_data->cur_chip; struct spi_message *msg = drv_data->cur_msg; int n_bytes = drv_data->n_bytes; /* wait until transfer finished. */ while (!(read_STAT(drv_data) & BIT_STAT_RXS)) cpu_relax(); if ((drv_data->tx && drv_data->tx >= drv_data->tx_end) || (drv_data->rx && drv_data->rx >= (drv_data->rx_end - n_bytes))) { /* last read */ if (drv_data->rx) { dev_dbg(&drv_data->pdev->dev, "last read\n"); if (n_bytes == 2) *(u16 *) (drv_data->rx) = read_RDBR(drv_data); else if (n_bytes == 1) *(u8 *) (drv_data->rx) = read_RDBR(drv_data); drv_data->rx += n_bytes; } msg->actual_length += drv_data->len_in_bytes; if (drv_data->cs_change) bfin_spi_cs_deactive(drv_data, chip); /* Move to next transfer */ msg->state = bfin_spi_next_transfer(drv_data); disable_irq_nosync(drv_data->spi_irq); /* Schedule transfer tasklet */ tasklet_schedule(&drv_data->pump_transfers); return IRQ_HANDLED; } if (drv_data->rx && drv_data->tx) { /* duplex */ dev_dbg(&drv_data->pdev->dev, "duplex: write_TDBR\n"); if (drv_data->n_bytes == 2) { *(u16 *) (drv_data->rx) = read_RDBR(drv_data); write_TDBR(drv_data, (*(u16 *) (drv_data->tx))); } else if (drv_data->n_bytes == 1) { *(u8 *) (drv_data->rx) = read_RDBR(drv_data); write_TDBR(drv_data, (*(u8 *) (drv_data->tx))); } } else if (drv_data->rx) { /* read */ dev_dbg(&drv_data->pdev->dev, "read: write_TDBR\n"); if (drv_data->n_bytes == 2) *(u16 *) (drv_data->rx) = read_RDBR(drv_data); else if (drv_data->n_bytes == 1) *(u8 *) (drv_data->rx) = read_RDBR(drv_data); write_TDBR(drv_data, chip->idle_tx_val); } else if (drv_data->tx) { /* write */ dev_dbg(&drv_data->pdev->dev, "write: write_TDBR\n"); bfin_spi_dummy_read(drv_data); if (drv_data->n_bytes == 2) write_TDBR(drv_data, (*(u16 *) (drv_data->tx))); else if (drv_data->n_bytes == 1) write_TDBR(drv_data, (*(u8 *) (drv_data->tx))); } if (drv_data->tx) drv_data->tx += n_bytes; if (drv_data->rx) drv_data->rx += n_bytes; return IRQ_HANDLED; } static irqreturn_t bfin_spi_dma_irq_handler(int irq, void *dev_id) { struct bfin_spi_master_data *drv_data = dev_id; struct bfin_spi_slave_data *chip = drv_data->cur_chip; struct spi_message *msg = drv_data->cur_msg; unsigned long timeout; unsigned short dmastat = get_dma_curr_irqstat(drv_data->dma_channel); u16 spistat = read_STAT(drv_data); dev_dbg(&drv_data->pdev->dev, "in dma_irq_handler dmastat:0x%x spistat:0x%x\n", dmastat, spistat); if (drv_data->rx != NULL) { u16 cr = read_CTRL(drv_data); /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); write_CTRL(drv_data, cr & ~BIT_CTL_ENABLE); /* Disable SPI */ write_CTRL(drv_data, cr & ~BIT_CTL_TIMOD); /* Restore State */ write_STAT(drv_data, BIT_STAT_CLR); /* Clear Status */ } clear_dma_irqstat(drv_data->dma_channel); /* * wait for the last transaction shifted out. HRM states: * at this point there may still be data in the SPI DMA FIFO waiting * to be transmitted ... software needs to poll TXS in the SPI_STAT * register until it goes low for 2 successive reads */ if (drv_data->tx != NULL) { while ((read_STAT(drv_data) & BIT_STAT_TXS) || (read_STAT(drv_data) & BIT_STAT_TXS)) cpu_relax(); } dev_dbg(&drv_data->pdev->dev, "in dma_irq_handler dmastat:0x%x spistat:0x%x\n", dmastat, read_STAT(drv_data)); timeout = jiffies + HZ; while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) if (!time_before(jiffies, timeout)) { dev_warn(&drv_data->pdev->dev, "timeout waiting for SPIF"); break; } else cpu_relax(); if ((dmastat & DMA_ERR) && (spistat & BIT_STAT_RBSY)) { msg->state = ERROR_STATE; dev_err(&drv_data->pdev->dev, "dma receive: fifo/buffer overflow\n"); } else { msg->actual_length += drv_data->len_in_bytes; if (drv_data->cs_change) bfin_spi_cs_deactive(drv_data, chip); /* Move to next transfer */ msg->state = bfin_spi_next_transfer(drv_data); } /* Schedule transfer tasklet */ tasklet_schedule(&drv_data->pump_transfers); /* free the irq handler before next transfer */ dev_dbg(&drv_data->pdev->dev, "disable dma channel irq%d\n", drv_data->dma_channel); dma_disable_irq_nosync(drv_data->dma_channel); return IRQ_HANDLED; } static void bfin_spi_pump_transfers(unsigned long data) { struct bfin_spi_master_data *drv_data = (struct bfin_spi_master_data *)data; struct spi_message *message = NULL; struct spi_transfer *transfer = NULL; struct spi_transfer *previous = NULL; struct bfin_spi_slave_data *chip = NULL; unsigned int bits_per_word; u16 cr, cr_width, dma_width, dma_config; u32 tranf_success = 1; u8 full_duplex = 0; /* Get current state information */ message = drv_data->cur_msg; transfer = drv_data->cur_transfer; chip = drv_data->cur_chip; /* * if msg is error or done, report it back using complete() callback */ /* Handle for abort */ if (message->state == ERROR_STATE) { dev_dbg(&drv_data->pdev->dev, "transfer: we've hit an error\n"); message->status = -EIO; bfin_spi_giveback(drv_data); return; } /* Handle end of message */ if (message->state == DONE_STATE) { dev_dbg(&drv_data->pdev->dev, "transfer: all done!\n"); message->status = 0; bfin_spi_giveback(drv_data); return; } /* Delay if requested at end of transfer */ if (message->state == RUNNING_STATE) { dev_dbg(&drv_data->pdev->dev, "transfer: still running ...\n"); previous = list_entry(transfer->transfer_list.prev, struct spi_transfer, transfer_list); if (previous->delay_usecs) udelay(previous->delay_usecs); } /* Flush any existing transfers that may be sitting in the hardware */ if (bfin_spi_flush(drv_data) == 0) { dev_err(&drv_data->pdev->dev, "pump_transfers: flush failed\n"); message->status = -EIO; bfin_spi_giveback(drv_data); return; } if (transfer->len == 0) { /* Move to next transfer of this msg */ message->state = bfin_spi_next_transfer(drv_data); /* Schedule next transfer tasklet */ tasklet_schedule(&drv_data->pump_transfers); } if (transfer->tx_buf != NULL) { drv_data->tx = (void *)transfer->tx_buf; drv_data->tx_end = drv_data->tx + transfer->len; dev_dbg(&drv_data->pdev->dev, "tx_buf is %p, tx_end is %p\n", transfer->tx_buf, drv_data->tx_end); } else { drv_data->tx = NULL; } if (transfer->rx_buf != NULL) { full_duplex = transfer->tx_buf != NULL; drv_data->rx = transfer->rx_buf; drv_data->rx_end = drv_data->rx + transfer->len; dev_dbg(&drv_data->pdev->dev, "rx_buf is %p, rx_end is %p\n", transfer->rx_buf, drv_data->rx_end); } else { drv_data->rx = NULL; } drv_data->rx_dma = transfer->rx_dma; drv_data->tx_dma = transfer->tx_dma; drv_data->len_in_bytes = transfer->len; drv_data->cs_change = transfer->cs_change; /* Bits per word setup */ bits_per_word = transfer->bits_per_word ? : message->spi->bits_per_word; if (bits_per_word == 8) { drv_data->n_bytes = 1; drv_data->len = transfer->len; cr_width = 0; drv_data->ops = &bfin_bfin_spi_transfer_ops_u8; } else if (bits_per_word == 16) { drv_data->n_bytes = 2; drv_data->len = (transfer->len) >> 1; cr_width = BIT_CTL_WORDSIZE; drv_data->ops = &bfin_bfin_spi_transfer_ops_u16; } else { dev_err(&drv_data->pdev->dev, "transfer: unsupported bits_per_word\n"); message->status = -EINVAL; bfin_spi_giveback(drv_data); return; } cr = read_CTRL(drv_data) & ~(BIT_CTL_TIMOD | BIT_CTL_WORDSIZE); cr |= cr_width; write_CTRL(drv_data, cr); dev_dbg(&drv_data->pdev->dev, "transfer: drv_data->ops is %p, chip->ops is %p, u8_ops is %p\n", drv_data->ops, chip->ops, &bfin_bfin_spi_transfer_ops_u8); message->state = RUNNING_STATE; dma_config = 0; /* Speed setup (surely valid because already checked) */ if (transfer->speed_hz) write_BAUD(drv_data, hz_to_spi_baud(transfer->speed_hz)); else write_BAUD(drv_data, chip->baud); write_STAT(drv_data, BIT_STAT_CLR); bfin_spi_cs_active(drv_data, chip); dev_dbg(&drv_data->pdev->dev, "now pumping a transfer: width is %d, len is %d\n", cr_width, transfer->len); /* * Try to map dma buffer and do a dma transfer. If successful use, * different way to r/w according to the enable_dma settings and if * we are not doing a full duplex transfer (since the hardware does * not support full duplex DMA transfers). */ if (!full_duplex && drv_data->cur_chip->enable_dma && drv_data->len > 6) { unsigned long dma_start_addr, flags; disable_dma(drv_data->dma_channel); clear_dma_irqstat(drv_data->dma_channel); /* config dma channel */ dev_dbg(&drv_data->pdev->dev, "doing dma transfer\n"); set_dma_x_count(drv_data->dma_channel, drv_data->len); if (cr_width == BIT_CTL_WORDSIZE) { set_dma_x_modify(drv_data->dma_channel, 2); dma_width = WDSIZE_16; } else { set_dma_x_modify(drv_data->dma_channel, 1); dma_width = WDSIZE_8; } /* poll for SPI completion before start */ while (!(read_STAT(drv_data) & BIT_STAT_SPIF)) cpu_relax(); /* dirty hack for autobuffer DMA mode */ if (drv_data->tx_dma == 0xFFFF) { dev_dbg(&drv_data->pdev->dev, "doing autobuffer DMA out.\n"); /* no irq in autobuffer mode */ dma_config = (DMAFLOW_AUTO | RESTART | dma_width | DI_EN); set_dma_config(drv_data->dma_channel, dma_config); set_dma_start_addr(drv_data->dma_channel, (unsigned long)drv_data->tx); enable_dma(drv_data->dma_channel); /* start SPI transfer */ write_CTRL(drv_data, cr | BIT_CTL_TIMOD_DMA_TX); /* just return here, there can only be one transfer * in this mode */ message->status = 0; bfin_spi_giveback(drv_data); return; } /* In dma mode, rx or tx must be NULL in one transfer */ dma_config = (RESTART | dma_width | DI_EN); if (drv_data->rx != NULL) { /* set transfer mode, and enable SPI */ dev_dbg(&drv_data->pdev->dev, "doing DMA in to %p (size %zx)\n", drv_data->rx, drv_data->len_in_bytes); /* invalidate caches, if needed */ if (bfin_addr_dcacheable((unsigned long) drv_data->rx)) invalidate_dcache_range((unsigned long) drv_data->rx, (unsigned long) (drv_data->rx + drv_data->len_in_bytes)); dma_config |= WNR; dma_start_addr = (unsigned long)drv_data->rx; cr |= BIT_CTL_TIMOD_DMA_RX | BIT_CTL_SENDOPT; } else if (drv_data->tx != NULL) { dev_dbg(&drv_data->pdev->dev, "doing DMA out.\n"); /* flush caches, if needed */ if (bfin_addr_dcacheable((unsigned long) drv_data->tx)) flush_dcache_range((unsigned long) drv_data->tx, (unsigned long) (drv_data->tx + drv_data->len_in_bytes)); dma_start_addr = (unsigned long)drv_data->tx; cr |= BIT_CTL_TIMOD_DMA_TX; } else BUG(); /* oh man, here there be monsters ... and i dont mean the * fluffy cute ones from pixar, i mean the kind that'll eat * your data, kick your dog, and love it all. do *not* try * and change these lines unless you (1) heavily test DMA * with SPI flashes on a loaded system (e.g. ping floods), * (2) know just how broken the DMA engine interaction with * the SPI peripheral is, and (3) have someone else to blame * when you screw it all up anyways. */ set_dma_start_addr(drv_data->dma_channel, dma_start_addr); set_dma_config(drv_data->dma_channel, dma_config); local_irq_save(flags); SSYNC(); write_CTRL(drv_data, cr); enable_dma(drv_data->dma_channel); dma_enable_irq(drv_data->dma_channel); local_irq_restore(flags); return; } /* * We always use SPI_WRITE mode (transfer starts with TDBR write). * SPI_READ mode (transfer starts with RDBR read) seems to have * problems with setting up the output value in TDBR prior to the * start of the transfer. */ write_CTRL(drv_data, cr | BIT_CTL_TXMOD); if (chip->pio_interrupt) { /* SPI irq should have been disabled by now */ /* discard old RX data and clear RXS */ bfin_spi_dummy_read(drv_data); /* start transfer */ if (drv_data->tx == NULL) write_TDBR(drv_data, chip->idle_tx_val); else { if (bits_per_word == 8) write_TDBR(drv_data, (*(u8 *) (drv_data->tx))); else write_TDBR(drv_data, (*(u16 *) (drv_data->tx))); drv_data->tx += drv_data->n_bytes; } /* once TDBR is empty, interrupt is triggered */ enable_irq(drv_data->spi_irq); return; } /* IO mode */ dev_dbg(&drv_data->pdev->dev, "doing IO transfer\n"); if (full_duplex) { /* full duplex mode */ BUG_ON((drv_data->tx_end - drv_data->tx) != (drv_data->rx_end - drv_data->rx)); dev_dbg(&drv_data->pdev->dev, "IO duplex: cr is 0x%x\n", cr); drv_data->ops->duplex(drv_data); if (drv_data->tx != drv_data->tx_end) tranf_success = 0; } else if (drv_data->tx != NULL) { /* write only half duplex */ dev_dbg(&drv_data->pdev->dev, "IO write: cr is 0x%x\n", cr); drv_data->ops->write(drv_data); if (drv_data->tx != drv_data->tx_end) tranf_success = 0; } else if (drv_data->rx != NULL) { /* read only half duplex */ dev_dbg(&drv_data->pdev->dev, "IO read: cr is 0x%x\n", cr); drv_data->ops->read(drv_data); if (drv_data->rx != drv_data->rx_end) tranf_success = 0; } if (!tranf_success) { dev_dbg(&drv_data->pdev->dev, "IO write error!\n"); message->state = ERROR_STATE; } else { /* Update total byte transfered */ message->actual_length += drv_data->len_in_bytes; /* Move to next transfer of this msg */ message->state = bfin_spi_next_transfer(drv_data); if (drv_data->cs_change) bfin_spi_cs_deactive(drv_data, chip); } /* Schedule next transfer tasklet */ tasklet_schedule(&drv_data->pump_transfers); } /* pop a msg from queue and kick off real transfer */ static void bfin_spi_pump_messages(struct work_struct *work) { struct bfin_spi_master_data *drv_data; unsigned long flags; drv_data = container_of(work, struct bfin_spi_master_data, pump_messages); /* Lock queue and check for queue work */ spin_lock_irqsave(&drv_data->lock, flags); if (list_empty(&drv_data->queue) || !drv_data->running) { /* pumper kicked off but no work to do */ drv_data->busy = 0; spin_unlock_irqrestore(&drv_data->lock, flags); return; } /* Make sure we are not already running a message */ if (drv_data->cur_msg) { spin_unlock_irqrestore(&drv_data->lock, flags); return; } /* Extract head of queue */ drv_data->cur_msg = list_entry(drv_data->queue.next, struct spi_message, queue); /* Setup the SSP using the per chip configuration */ drv_data->cur_chip = spi_get_ctldata(drv_data->cur_msg->spi); bfin_spi_restore_state(drv_data); list_del_init(&drv_data->cur_msg->queue); /* Initial message state */ drv_data->cur_msg->state = START_STATE; drv_data->cur_transfer = list_entry(drv_data->cur_msg->transfers.next, struct spi_transfer, transfer_list); dev_dbg(&drv_data->pdev->dev, "got a message to pump, " "state is set to: baud %d, flag 0x%x, ctl 0x%x\n", drv_data->cur_chip->baud, drv_data->cur_chip->flag, drv_data->cur_chip->ctl_reg); dev_dbg(&drv_data->pdev->dev, "the first transfer len is %d\n", drv_data->cur_transfer->len); /* Mark as busy and launch transfers */ tasklet_schedule(&drv_data->pump_transfers); drv_data->busy = 1; spin_unlock_irqrestore(&drv_data->lock, flags); } /* * got a msg to transfer, queue it in drv_data->queue. * And kick off message pumper */ static int bfin_spi_transfer(struct spi_device *spi, struct spi_message *msg) { struct bfin_spi_master_data *drv_data = spi_master_get_devdata(spi->master); unsigned long flags; spin_lock_irqsave(&drv_data->lock, flags); if (!drv_data->running) { spin_unlock_irqrestore(&drv_data->lock, flags); return -ESHUTDOWN; } msg->actual_length = 0; msg->status = -EINPROGRESS; msg->state = START_STATE; dev_dbg(&spi->dev, "adding an msg in transfer() \n"); list_add_tail(&msg->queue, &drv_data->queue); if (drv_data->running && !drv_data->busy) queue_work(drv_data->workqueue, &drv_data->pump_messages); spin_unlock_irqrestore(&drv_data->lock, flags); return 0; } #define MAX_SPI_SSEL 7 static u16 ssel[][MAX_SPI_SSEL] = { {P_SPI0_SSEL1, P_SPI0_SSEL2, P_SPI0_SSEL3, P_SPI0_SSEL4, P_SPI0_SSEL5, P_SPI0_SSEL6, P_SPI0_SSEL7}, {P_SPI1_SSEL1, P_SPI1_SSEL2, P_SPI1_SSEL3, P_SPI1_SSEL4, P_SPI1_SSEL5, P_SPI1_SSEL6, P_SPI1_SSEL7}, {P_SPI2_SSEL1, P_SPI2_SSEL2, P_SPI2_SSEL3, P_SPI2_SSEL4, P_SPI2_SSEL5, P_SPI2_SSEL6, P_SPI2_SSEL7}, }; /* setup for devices (may be called multiple times -- not just first setup) */ static int bfin_spi_setup(struct spi_device *spi) { struct bfin5xx_spi_chip *chip_info; struct bfin_spi_slave_data *chip = NULL; struct bfin_spi_master_data *drv_data = spi_master_get_devdata(spi->master); u16 bfin_ctl_reg; int ret = -EINVAL; /* Only alloc (or use chip_info) on first setup */ chip_info = NULL; chip = spi_get_ctldata(spi); if (chip == NULL) { chip = kzalloc(sizeof(*chip), GFP_KERNEL); if (!chip) { dev_err(&spi->dev, "cannot allocate chip data\n"); ret = -ENOMEM; goto error; } chip->enable_dma = 0; chip_info = spi->controller_data; } /* Let people set non-standard bits directly */ bfin_ctl_reg = BIT_CTL_OPENDRAIN | BIT_CTL_EMISO | BIT_CTL_PSSE | BIT_CTL_GM | BIT_CTL_SZ; /* chip_info isn't always needed */ if (chip_info) { /* Make sure people stop trying to set fields via ctl_reg * when they should actually be using common SPI framework. * Currently we let through: WOM EMISO PSSE GM SZ. * Not sure if a user actually needs/uses any of these, * but let's assume (for now) they do. */ if (chip_info->ctl_reg & ~bfin_ctl_reg) { dev_err(&spi->dev, "do not set bits in ctl_reg " "that the SPI framework manages\n"); goto error; } chip->enable_dma = chip_info->enable_dma != 0 && drv_data->master_info->enable_dma; chip->ctl_reg = chip_info->ctl_reg; chip->cs_chg_udelay = chip_info->cs_chg_udelay; chip->idle_tx_val = chip_info->idle_tx_val; chip->pio_interrupt = chip_info->pio_interrupt; spi->bits_per_word = chip_info->bits_per_word; } else { /* force a default base state */ chip->ctl_reg &= bfin_ctl_reg; } if (spi->bits_per_word != 8 && spi->bits_per_word != 16) { dev_err(&spi->dev, "%d bits_per_word is not supported\n", spi->bits_per_word); goto error; } /* translate common spi framework into our register */ if (spi->mode & ~(SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST)) { dev_err(&spi->dev, "unsupported spi modes detected\n"); goto error; } if (spi->mode & SPI_CPOL) chip->ctl_reg |= BIT_CTL_CPOL; if (spi->mode & SPI_CPHA) chip->ctl_reg |= BIT_CTL_CPHA; if (spi->mode & SPI_LSB_FIRST) chip->ctl_reg |= BIT_CTL_LSBF; /* we dont support running in slave mode (yet?) */ chip->ctl_reg |= BIT_CTL_MASTER; /* * Notice: for blackfin, the speed_hz is the value of register * SPI_BAUD, not the real baudrate */ chip->baud = hz_to_spi_baud(spi->max_speed_hz); chip->chip_select_num = spi->chip_select; if (chip->chip_select_num < MAX_CTRL_CS) { if (!(spi->mode & SPI_CPHA)) dev_warn(&spi->dev, "Warning: SPI CPHA not set:" " Slave Select not under software control!\n" " See Documentation/blackfin/bfin-spi-notes.txt"); chip->flag = (1 << spi->chip_select) << 8; } else chip->cs_gpio = chip->chip_select_num - MAX_CTRL_CS; if (chip->enable_dma && chip->pio_interrupt) { dev_err(&spi->dev, "enable_dma is set, " "do not set pio_interrupt\n"); goto error; } /* * if any one SPI chip is registered and wants DMA, request the * DMA channel for it */ if (chip->enable_dma && !drv_data->dma_requested) { /* register dma irq handler */ ret = request_dma(drv_data->dma_channel, "BFIN_SPI_DMA"); if (ret) { dev_err(&spi->dev, "Unable to request BlackFin SPI DMA channel\n"); goto error; } drv_data->dma_requested = 1; ret = set_dma_callback(drv_data->dma_channel, bfin_spi_dma_irq_handler, drv_data); if (ret) { dev_err(&spi->dev, "Unable to set dma callback\n"); goto error; } dma_disable_irq(drv_data->dma_channel); } if (chip->pio_interrupt && !drv_data->irq_requested) { ret = request_irq(drv_data->spi_irq, bfin_spi_pio_irq_handler, IRQF_DISABLED, "BFIN_SPI", drv_data); if (ret) { dev_err(&spi->dev, "Unable to register spi IRQ\n"); goto error; } drv_data->irq_requested = 1; /* we use write mode, spi irq has to be disabled here */ disable_irq(drv_data->spi_irq); } if (chip->chip_select_num >= MAX_CTRL_CS) { ret = gpio_request(chip->cs_gpio, spi->modalias); if (ret) { dev_err(&spi->dev, "gpio_request() error\n"); goto pin_error; } gpio_direction_output(chip->cs_gpio, 1); } dev_dbg(&spi->dev, "setup spi chip %s, width is %d, dma is %d\n", spi->modalias, spi->bits_per_word, chip->enable_dma); dev_dbg(&spi->dev, "ctl_reg is 0x%x, flag_reg is 0x%x\n", chip->ctl_reg, chip->flag); spi_set_ctldata(spi, chip); dev_dbg(&spi->dev, "chip select number is %d\n", chip->chip_select_num); if (chip->chip_select_num < MAX_CTRL_CS) { ret = peripheral_request(ssel[spi->master->bus_num] [chip->chip_select_num-1], spi->modalias); if (ret) { dev_err(&spi->dev, "peripheral_request() error\n"); goto pin_error; } } bfin_spi_cs_enable(drv_data, chip); bfin_spi_cs_deactive(drv_data, chip); return 0; pin_error: if (chip->chip_select_num >= MAX_CTRL_CS) gpio_free(chip->cs_gpio); else peripheral_free(ssel[spi->master->bus_num] [chip->chip_select_num - 1]); error: if (chip) { if (drv_data->dma_requested) free_dma(drv_data->dma_channel); drv_data->dma_requested = 0; kfree(chip); /* prevent free 'chip' twice */ spi_set_ctldata(spi, NULL); } return ret; } /* * callback for spi framework. * clean driver specific data */ static void bfin_spi_cleanup(struct spi_device *spi) { struct bfin_spi_slave_data *chip = spi_get_ctldata(spi); struct bfin_spi_master_data *drv_data = spi_master_get_devdata(spi->master); if (!chip) return; if (chip->chip_select_num < MAX_CTRL_CS) { peripheral_free(ssel[spi->master->bus_num] [chip->chip_select_num-1]); bfin_spi_cs_disable(drv_data, chip); } else gpio_free(chip->cs_gpio); kfree(chip); /* prevent free 'chip' twice */ spi_set_ctldata(spi, NULL); } static inline int bfin_spi_init_queue(struct bfin_spi_master_data *drv_data) { INIT_LIST_HEAD(&drv_data->queue); spin_lock_init(&drv_data->lock); drv_data->running = false; drv_data->busy = 0; /* init transfer tasklet */ tasklet_init(&drv_data->pump_transfers, bfin_spi_pump_transfers, (unsigned long)drv_data); /* init messages workqueue */ INIT_WORK(&drv_data->pump_messages, bfin_spi_pump_messages); drv_data->workqueue = create_singlethread_workqueue( dev_name(drv_data->master->dev.parent)); if (drv_data->workqueue == NULL) return -EBUSY; return 0; } static inline int bfin_spi_start_queue(struct bfin_spi_master_data *drv_data) { unsigned long flags; spin_lock_irqsave(&drv_data->lock, flags); if (drv_data->running || drv_data->busy) { spin_unlock_irqrestore(&drv_data->lock, flags); return -EBUSY; } drv_data->running = true; drv_data->cur_msg = NULL; drv_data->cur_transfer = NULL; drv_data->cur_chip = NULL; spin_unlock_irqrestore(&drv_data->lock, flags); queue_work(drv_data->workqueue, &drv_data->pump_messages); return 0; } static inline int bfin_spi_stop_queue(struct bfin_spi_master_data *drv_data) { unsigned long flags; unsigned limit = 500; int status = 0; spin_lock_irqsave(&drv_data->lock, flags); /* * This is a bit lame, but is optimized for the common execution path. * A wait_queue on the drv_data->busy could be used, but then the common * execution path (pump_messages) would be required to call wake_up or * friends on every SPI message. Do this instead */ drv_data->running = false; while (!list_empty(&drv_data->queue) && drv_data->busy && limit--) { spin_unlock_irqrestore(&drv_data->lock, flags); msleep(10); spin_lock_irqsave(&drv_data->lock, flags); } if (!list_empty(&drv_data->queue) || drv_data->busy) status = -EBUSY; spin_unlock_irqrestore(&drv_data->lock, flags); return status; } static inline int bfin_spi_destroy_queue(struct bfin_spi_master_data *drv_data) { int status; status = bfin_spi_stop_queue(drv_data); if (status != 0) return status; destroy_workqueue(drv_data->workqueue); return 0; } static int __init bfin_spi_probe(struct platform_device *pdev) { struct device *dev = &pdev->dev; struct bfin5xx_spi_master *platform_info; struct spi_master *master; struct bfin_spi_master_data *drv_data; struct resource *res; int status = 0; platform_info = dev->platform_data; /* Allocate master with space for drv_data */ master = spi_alloc_master(dev, sizeof(*drv_data)); if (!master) { dev_err(&pdev->dev, "can not alloc spi_master\n"); return -ENOMEM; } drv_data = spi_master_get_devdata(master); drv_data->master = master; drv_data->master_info = platform_info; drv_data->pdev = pdev; drv_data->pin_req = platform_info->pin_req; /* the spi->mode bits supported by this driver: */ master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST; master->bus_num = pdev->id; master->num_chipselect = platform_info->num_chipselect; master->cleanup = bfin_spi_cleanup; master->setup = bfin_spi_setup; master->transfer = bfin_spi_transfer; /* Find and map our resources */ res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (res == NULL) { dev_err(dev, "Cannot get IORESOURCE_MEM\n"); status = -ENOENT; goto out_error_get_res; } drv_data->regs_base = ioremap(res->start, resource_size(res)); if (drv_data->regs_base == NULL) { dev_err(dev, "Cannot map IO\n"); status = -ENXIO; goto out_error_ioremap; } res = platform_get_resource(pdev, IORESOURCE_DMA, 0); if (res == NULL) { dev_err(dev, "No DMA channel specified\n"); status = -ENOENT; goto out_error_free_io; } drv_data->dma_channel = res->start; drv_data->spi_irq = platform_get_irq(pdev, 0); if (drv_data->spi_irq < 0) { dev_err(dev, "No spi pio irq specified\n"); status = -ENOENT; goto out_error_free_io; } /* Initial and start queue */ status = bfin_spi_init_queue(drv_data); if (status != 0) { dev_err(dev, "problem initializing queue\n"); goto out_error_queue_alloc; } status = bfin_spi_start_queue(drv_data); if (status != 0) { dev_err(dev, "problem starting queue\n"); goto out_error_queue_alloc; } status = peripheral_request_list(drv_data->pin_req, DRV_NAME); if (status != 0) { dev_err(&pdev->dev, ": Requesting Peripherals failed\n"); goto out_error_queue_alloc; } /* Reset SPI registers. If these registers were used by the boot loader, * the sky may fall on your head if you enable the dma controller. */ write_CTRL(drv_data, BIT_CTL_CPHA | BIT_CTL_MASTER); write_FLAG(drv_data, 0xFF00); /* Register with the SPI framework */ platform_set_drvdata(pdev, drv_data); status = spi_register_master(master); if (status != 0) { dev_err(dev, "problem registering spi master\n"); goto out_error_queue_alloc; } dev_info(dev, "%s, Version %s, regs_base@%p, dma channel@%d\n", DRV_DESC, DRV_VERSION, drv_data->regs_base, drv_data->dma_channel); return status; out_error_queue_alloc: bfin_spi_destroy_queue(drv_data); out_error_free_io: iounmap((void *) drv_data->regs_base); out_error_ioremap: out_error_get_res: spi_master_put(master); return status; } /* stop hardware and remove the driver */ static int __devexit bfin_spi_remove(struct platform_device *pdev) { struct bfin_spi_master_data *drv_data = platform_get_drvdata(pdev); int status = 0; if (!drv_data) return 0; /* Remove the queue */ status = bfin_spi_destroy_queue(drv_data); if (status != 0) return status; /* Disable the SSP at the peripheral and SOC level */ bfin_spi_disable(drv_data); /* Release DMA */ if (drv_data->master_info->enable_dma) { if (dma_channel_active(drv_data->dma_channel)) free_dma(drv_data->dma_channel); } if (drv_data->irq_requested) { free_irq(drv_data->spi_irq, drv_data); drv_data->irq_requested = 0; } /* Disconnect from the SPI framework */ spi_unregister_master(drv_data->master); peripheral_free_list(drv_data->pin_req); /* Prevent double remove */ platform_set_drvdata(pdev, NULL); return 0; } #ifdef CONFIG_PM static int bfin_spi_suspend(struct platform_device *pdev, pm_message_t state) { struct bfin_spi_master_data *drv_data = platform_get_drvdata(pdev); int status = 0; status = bfin_spi_stop_queue(drv_data); if (status != 0) return status; drv_data->ctrl_reg = read_CTRL(drv_data); drv_data->flag_reg = read_FLAG(drv_data); /* * reset SPI_CTL and SPI_FLG registers */ write_CTRL(drv_data, BIT_CTL_CPHA | BIT_CTL_MASTER); write_FLAG(drv_data, 0xFF00); return 0; } static int bfin_spi_resume(struct platform_device *pdev) { struct bfin_spi_master_data *drv_data = platform_get_drvdata(pdev); int status = 0; write_CTRL(drv_data, drv_data->ctrl_reg); write_FLAG(drv_data, drv_data->flag_reg); /* Start the queue running */ status = bfin_spi_start_queue(drv_data); if (status != 0) { dev_err(&pdev->dev, "problem starting queue (%d)\n", status); return status; } return 0; } #else #define bfin_spi_suspend NULL #define bfin_spi_resume NULL #endif /* CONFIG_PM */ MODULE_ALIAS("platform:bfin-spi"); static struct platform_driver bfin_spi_driver = { .driver = { .name = DRV_NAME, .owner = THIS_MODULE, }, .suspend = bfin_spi_suspend, .resume = bfin_spi_resume, .remove = __devexit_p(bfin_spi_remove), }; static int __init bfin_spi_init(void) { return platform_driver_probe(&bfin_spi_driver, bfin_spi_probe); } subsys_initcall(bfin_spi_init); static void __exit bfin_spi_exit(void) { platform_driver_unregister(&bfin_spi_driver); } module_exit(bfin_spi_exit);