/* * Driver for Cirrus Logic EP93xx SPI controller. * * Copyright (C) 2010-2011 Mika Westerberg * * Explicit FIFO handling code was inspired by amba-pl022 driver. * * Chip select support using other than built-in GPIOs by H. Hartley Sweeten. * * For more information about the SPI controller see documentation on Cirrus * Logic web site: * http://www.cirrus.com/en/pubs/manual/EP93xx_Users_Guide_UM1.pdf * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as * published by the Free Software Foundation. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define SSPCR0 0x0000 #define SSPCR0_MODE_SHIFT 6 #define SSPCR0_SCR_SHIFT 8 #define SSPCR1 0x0004 #define SSPCR1_RIE BIT(0) #define SSPCR1_TIE BIT(1) #define SSPCR1_RORIE BIT(2) #define SSPCR1_LBM BIT(3) #define SSPCR1_SSE BIT(4) #define SSPCR1_MS BIT(5) #define SSPCR1_SOD BIT(6) #define SSPDR 0x0008 #define SSPSR 0x000c #define SSPSR_TFE BIT(0) #define SSPSR_TNF BIT(1) #define SSPSR_RNE BIT(2) #define SSPSR_RFF BIT(3) #define SSPSR_BSY BIT(4) #define SSPCPSR 0x0010 #define SSPIIR 0x0014 #define SSPIIR_RIS BIT(0) #define SSPIIR_TIS BIT(1) #define SSPIIR_RORIS BIT(2) #define SSPICR SSPIIR /* timeout in milliseconds */ #define SPI_TIMEOUT 5 /* maximum depth of RX/TX FIFO */ #define SPI_FIFO_SIZE 8 /** * struct ep93xx_spi - EP93xx SPI controller structure * @lock: spinlock that protects concurrent accesses to fields @running, * @current_msg and @msg_queue * @pdev: pointer to platform device * @clk: clock for the controller * @regs_base: pointer to ioremap()'d registers * @sspdr_phys: physical address of the SSPDR register * @min_rate: minimum clock rate (in Hz) supported by the controller * @max_rate: maximum clock rate (in Hz) supported by the controller * @running: is the queue running * @wq: workqueue used by the driver * @msg_work: work that is queued for the driver * @wait: wait here until given transfer is completed * @msg_queue: queue for the messages * @current_msg: message that is currently processed (or %NULL if none) * @tx: current byte in transfer to transmit * @rx: current byte in transfer to receive * @fifo_level: how full is FIFO (%0..%SPI_FIFO_SIZE - %1). Receiving one * frame decreases this level and sending one frame increases it. * @dma_rx: RX DMA channel * @dma_tx: TX DMA channel * @dma_rx_data: RX parameters passed to the DMA engine * @dma_tx_data: TX parameters passed to the DMA engine * @rx_sgt: sg table for RX transfers * @tx_sgt: sg table for TX transfers * @zeropage: dummy page used as RX buffer when only TX buffer is passed in by * the client * * This structure holds EP93xx SPI controller specific information. When * @running is %true, driver accepts transfer requests from protocol drivers. * @current_msg is used to hold pointer to the message that is currently * processed. If @current_msg is %NULL, it means that no processing is going * on. * * Most of the fields are only written once and they can be accessed without * taking the @lock. Fields that are accessed concurrently are: @current_msg, * @running, and @msg_queue. */ struct ep93xx_spi { spinlock_t lock; const struct platform_device *pdev; struct clk *clk; void __iomem *regs_base; unsigned long sspdr_phys; unsigned long min_rate; unsigned long max_rate; bool running; struct workqueue_struct *wq; struct work_struct msg_work; struct completion wait; struct list_head msg_queue; struct spi_message *current_msg; size_t tx; size_t rx; size_t fifo_level; struct dma_chan *dma_rx; struct dma_chan *dma_tx; struct ep93xx_dma_data dma_rx_data; struct ep93xx_dma_data dma_tx_data; struct sg_table rx_sgt; struct sg_table tx_sgt; void *zeropage; }; /** * struct ep93xx_spi_chip - SPI device hardware settings * @spi: back pointer to the SPI device * @rate: max rate in hz this chip supports * @div_cpsr: cpsr (pre-scaler) divider * @div_scr: scr divider * @dss: bits per word (4 - 16 bits) * @ops: private chip operations * * This structure is used to store hardware register specific settings for each * SPI device. Settings are written to hardware by function * ep93xx_spi_chip_setup(). */ struct ep93xx_spi_chip { const struct spi_device *spi; unsigned long rate; u8 div_cpsr; u8 div_scr; u8 dss; struct ep93xx_spi_chip_ops *ops; }; /* converts bits per word to CR0.DSS value */ #define bits_per_word_to_dss(bpw) ((bpw) - 1) static inline void ep93xx_spi_write_u8(const struct ep93xx_spi *espi, u16 reg, u8 value) { __raw_writeb(value, espi->regs_base + reg); } static inline u8 ep93xx_spi_read_u8(const struct ep93xx_spi *spi, u16 reg) { return __raw_readb(spi->regs_base + reg); } static inline void ep93xx_spi_write_u16(const struct ep93xx_spi *espi, u16 reg, u16 value) { __raw_writew(value, espi->regs_base + reg); } static inline u16 ep93xx_spi_read_u16(const struct ep93xx_spi *spi, u16 reg) { return __raw_readw(spi->regs_base + reg); } static int ep93xx_spi_enable(const struct ep93xx_spi *espi) { u8 regval; int err; err = clk_enable(espi->clk); if (err) return err; regval = ep93xx_spi_read_u8(espi, SSPCR1); regval |= SSPCR1_SSE; ep93xx_spi_write_u8(espi, SSPCR1, regval); return 0; } static void ep93xx_spi_disable(const struct ep93xx_spi *espi) { u8 regval; regval = ep93xx_spi_read_u8(espi, SSPCR1); regval &= ~SSPCR1_SSE; ep93xx_spi_write_u8(espi, SSPCR1, regval); clk_disable(espi->clk); } static void ep93xx_spi_enable_interrupts(const struct ep93xx_spi *espi) { u8 regval; regval = ep93xx_spi_read_u8(espi, SSPCR1); regval |= (SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE); ep93xx_spi_write_u8(espi, SSPCR1, regval); } static void ep93xx_spi_disable_interrupts(const struct ep93xx_spi *espi) { u8 regval; regval = ep93xx_spi_read_u8(espi, SSPCR1); regval &= ~(SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE); ep93xx_spi_write_u8(espi, SSPCR1, regval); } /** * ep93xx_spi_calc_divisors() - calculates SPI clock divisors * @espi: ep93xx SPI controller struct * @chip: divisors are calculated for this chip * @rate: desired SPI output clock rate * * Function calculates cpsr (clock pre-scaler) and scr divisors based on * given @rate and places them to @chip->div_cpsr and @chip->div_scr. If, * for some reason, divisors cannot be calculated nothing is stored and * %-EINVAL is returned. */ static int ep93xx_spi_calc_divisors(const struct ep93xx_spi *espi, struct ep93xx_spi_chip *chip, unsigned long rate) { unsigned long spi_clk_rate = clk_get_rate(espi->clk); int cpsr, scr; /* * Make sure that max value is between values supported by the * controller. Note that minimum value is already checked in * ep93xx_spi_transfer(). */ rate = clamp(rate, espi->min_rate, espi->max_rate); /* * Calculate divisors so that we can get speed according the * following formula: * rate = spi_clock_rate / (cpsr * (1 + scr)) * * cpsr must be even number and starts from 2, scr can be any number * between 0 and 255. */ for (cpsr = 2; cpsr <= 254; cpsr += 2) { for (scr = 0; scr <= 255; scr++) { if ((spi_clk_rate / (cpsr * (scr + 1))) <= rate) { chip->div_scr = (u8)scr; chip->div_cpsr = (u8)cpsr; return 0; } } } return -EINVAL; } static void ep93xx_spi_cs_control(struct spi_device *spi, bool control) { struct ep93xx_spi_chip *chip = spi_get_ctldata(spi); int value = (spi->mode & SPI_CS_HIGH) ? control : !control; if (chip->ops && chip->ops->cs_control) chip->ops->cs_control(spi, value); } /** * ep93xx_spi_setup() - setup an SPI device * @spi: SPI device to setup * * This function sets up SPI device mode, speed etc. Can be called multiple * times for a single device. Returns %0 in case of success, negative error in * case of failure. When this function returns success, the device is * deselected. */ static int ep93xx_spi_setup(struct spi_device *spi) { struct ep93xx_spi *espi = spi_master_get_devdata(spi->master); struct ep93xx_spi_chip *chip; if (spi->bits_per_word < 4 || spi->bits_per_word > 16) { dev_err(&espi->pdev->dev, "invalid bits per word %d\n", spi->bits_per_word); return -EINVAL; } chip = spi_get_ctldata(spi); if (!chip) { dev_dbg(&espi->pdev->dev, "initial setup for %s\n", spi->modalias); chip = kzalloc(sizeof(*chip), GFP_KERNEL); if (!chip) return -ENOMEM; chip->spi = spi; chip->ops = spi->controller_data; if (chip->ops && chip->ops->setup) { int ret = chip->ops->setup(spi); if (ret) { kfree(chip); return ret; } } spi_set_ctldata(spi, chip); } if (spi->max_speed_hz != chip->rate) { int err; err = ep93xx_spi_calc_divisors(espi, chip, spi->max_speed_hz); if (err != 0) { spi_set_ctldata(spi, NULL); kfree(chip); return err; } chip->rate = spi->max_speed_hz; } chip->dss = bits_per_word_to_dss(spi->bits_per_word); ep93xx_spi_cs_control(spi, false); return 0; } /** * ep93xx_spi_transfer() - queue message to be transferred * @spi: target SPI device * @msg: message to be transferred * * This function is called by SPI device drivers when they are going to transfer * a new message. It simply puts the message in the queue and schedules * workqueue to perform the actual transfer later on. * * Returns %0 on success and negative error in case of failure. */ static int ep93xx_spi_transfer(struct spi_device *spi, struct spi_message *msg) { struct ep93xx_spi *espi = spi_master_get_devdata(spi->master); struct spi_transfer *t; unsigned long flags; if (!msg || !msg->complete) return -EINVAL; /* first validate each transfer */ list_for_each_entry(t, &msg->transfers, transfer_list) { if (t->bits_per_word) { if (t->bits_per_word < 4 || t->bits_per_word > 16) return -EINVAL; } if (t->speed_hz && t->speed_hz < espi->min_rate) return -EINVAL; } /* * Now that we own the message, let's initialize it so that it is * suitable for us. We use @msg->status to signal whether there was * error in transfer and @msg->state is used to hold pointer to the * current transfer (or %NULL if no active current transfer). */ msg->state = NULL; msg->status = 0; msg->actual_length = 0; spin_lock_irqsave(&espi->lock, flags); if (!espi->running) { spin_unlock_irqrestore(&espi->lock, flags); return -ESHUTDOWN; } list_add_tail(&msg->queue, &espi->msg_queue); queue_work(espi->wq, &espi->msg_work); spin_unlock_irqrestore(&espi->lock, flags); return 0; } /** * ep93xx_spi_cleanup() - cleans up master controller specific state * @spi: SPI device to cleanup * * This function releases master controller specific state for given @spi * device. */ static void ep93xx_spi_cleanup(struct spi_device *spi) { struct ep93xx_spi_chip *chip; chip = spi_get_ctldata(spi); if (chip) { if (chip->ops && chip->ops->cleanup) chip->ops->cleanup(spi); spi_set_ctldata(spi, NULL); kfree(chip); } } /** * ep93xx_spi_chip_setup() - configures hardware according to given @chip * @espi: ep93xx SPI controller struct * @chip: chip specific settings * * This function sets up the actual hardware registers with settings given in * @chip. Note that no validation is done so make sure that callers validate * settings before calling this. */ static void ep93xx_spi_chip_setup(const struct ep93xx_spi *espi, const struct ep93xx_spi_chip *chip) { u16 cr0; cr0 = chip->div_scr << SSPCR0_SCR_SHIFT; cr0 |= (chip->spi->mode & (SPI_CPHA|SPI_CPOL)) << SSPCR0_MODE_SHIFT; cr0 |= chip->dss; dev_dbg(&espi->pdev->dev, "setup: mode %d, cpsr %d, scr %d, dss %d\n", chip->spi->mode, chip->div_cpsr, chip->div_scr, chip->dss); dev_dbg(&espi->pdev->dev, "setup: cr0 %#x", cr0); ep93xx_spi_write_u8(espi, SSPCPSR, chip->div_cpsr); ep93xx_spi_write_u16(espi, SSPCR0, cr0); } static inline int bits_per_word(const struct ep93xx_spi *espi) { struct spi_message *msg = espi->current_msg; struct spi_transfer *t = msg->state; return t->bits_per_word ? t->bits_per_word : msg->spi->bits_per_word; } static void ep93xx_do_write(struct ep93xx_spi *espi, struct spi_transfer *t) { if (bits_per_word(espi) > 8) { u16 tx_val = 0; if (t->tx_buf) tx_val = ((u16 *)t->tx_buf)[espi->tx]; ep93xx_spi_write_u16(espi, SSPDR, tx_val); espi->tx += sizeof(tx_val); } else { u8 tx_val = 0; if (t->tx_buf) tx_val = ((u8 *)t->tx_buf)[espi->tx]; ep93xx_spi_write_u8(espi, SSPDR, tx_val); espi->tx += sizeof(tx_val); } } static void ep93xx_do_read(struct ep93xx_spi *espi, struct spi_transfer *t) { if (bits_per_word(espi) > 8) { u16 rx_val; rx_val = ep93xx_spi_read_u16(espi, SSPDR); if (t->rx_buf) ((u16 *)t->rx_buf)[espi->rx] = rx_val; espi->rx += sizeof(rx_val); } else { u8 rx_val; rx_val = ep93xx_spi_read_u8(espi, SSPDR); if (t->rx_buf) ((u8 *)t->rx_buf)[espi->rx] = rx_val; espi->rx += sizeof(rx_val); } } /** * ep93xx_spi_read_write() - perform next RX/TX transfer * @espi: ep93xx SPI controller struct * * This function transfers next bytes (or half-words) to/from RX/TX FIFOs. If * called several times, the whole transfer will be completed. Returns * %-EINPROGRESS when current transfer was not yet completed otherwise %0. * * When this function is finished, RX FIFO should be empty and TX FIFO should be * full. */ static int ep93xx_spi_read_write(struct ep93xx_spi *espi) { struct spi_message *msg = espi->current_msg; struct spi_transfer *t = msg->state; /* read as long as RX FIFO has frames in it */ while ((ep93xx_spi_read_u8(espi, SSPSR) & SSPSR_RNE)) { ep93xx_do_read(espi, t); espi->fifo_level--; } /* write as long as TX FIFO has room */ while (espi->fifo_level < SPI_FIFO_SIZE && espi->tx < t->len) { ep93xx_do_write(espi, t); espi->fifo_level++; } if (espi->rx == t->len) return 0; return -EINPROGRESS; } static void ep93xx_spi_pio_transfer(struct ep93xx_spi *espi) { /* * Now everything is set up for the current transfer. We prime the TX * FIFO, enable interrupts, and wait for the transfer to complete. */ if (ep93xx_spi_read_write(espi)) { ep93xx_spi_enable_interrupts(espi); wait_for_completion(&espi->wait); } } /** * ep93xx_spi_dma_prepare() - prepares a DMA transfer * @espi: ep93xx SPI controller struct * @dir: DMA transfer direction * * Function configures the DMA, maps the buffer and prepares the DMA * descriptor. Returns a valid DMA descriptor in case of success and ERR_PTR * in case of failure. */ static struct dma_async_tx_descriptor * ep93xx_spi_dma_prepare(struct ep93xx_spi *espi, enum dma_transfer_direction dir) { struct spi_transfer *t = espi->current_msg->state; struct dma_async_tx_descriptor *txd; enum dma_slave_buswidth buswidth; struct dma_slave_config conf; struct scatterlist *sg; struct sg_table *sgt; struct dma_chan *chan; const void *buf, *pbuf; size_t len = t->len; int i, ret, nents; if (bits_per_word(espi) > 8) buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES; else buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE; memset(&conf, 0, sizeof(conf)); conf.direction = dir; if (dir == DMA_DEV_TO_MEM) { chan = espi->dma_rx; buf = t->rx_buf; sgt = &espi->rx_sgt; conf.src_addr = espi->sspdr_phys; conf.src_addr_width = buswidth; } else { chan = espi->dma_tx; buf = t->tx_buf; sgt = &espi->tx_sgt; conf.dst_addr = espi->sspdr_phys; conf.dst_addr_width = buswidth; } ret = dmaengine_slave_config(chan, &conf); if (ret) return ERR_PTR(ret); /* * We need to split the transfer into PAGE_SIZE'd chunks. This is * because we are using @espi->zeropage to provide a zero RX buffer * for the TX transfers and we have only allocated one page for that. * * For performance reasons we allocate a new sg_table only when * needed. Otherwise we will re-use the current one. Eventually the * last sg_table is released in ep93xx_spi_release_dma(). */ nents = DIV_ROUND_UP(len, PAGE_SIZE); if (nents != sgt->nents) { sg_free_table(sgt); ret = sg_alloc_table(sgt, nents, GFP_KERNEL); if (ret) return ERR_PTR(ret); } pbuf = buf; for_each_sg(sgt->sgl, sg, sgt->nents, i) { size_t bytes = min_t(size_t, len, PAGE_SIZE); if (buf) { sg_set_page(sg, virt_to_page(pbuf), bytes, offset_in_page(pbuf)); } else { sg_set_page(sg, virt_to_page(espi->zeropage), bytes, 0); } pbuf += bytes; len -= bytes; } if (WARN_ON(len)) { dev_warn(&espi->pdev->dev, "len = %d expected 0!", len); return ERR_PTR(-EINVAL); } nents = dma_map_sg(chan->device->dev, sgt->sgl, sgt->nents, dir); if (!nents) return ERR_PTR(-ENOMEM); txd = dmaengine_prep_slave_sg(chan, sgt->sgl, nents, dir, DMA_CTRL_ACK); if (!txd) { dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir); return ERR_PTR(-ENOMEM); } return txd; } /** * ep93xx_spi_dma_finish() - finishes with a DMA transfer * @espi: ep93xx SPI controller struct * @dir: DMA transfer direction * * Function finishes with the DMA transfer. After this, the DMA buffer is * unmapped. */ static void ep93xx_spi_dma_finish(struct ep93xx_spi *espi, enum dma_transfer_direction dir) { struct dma_chan *chan; struct sg_table *sgt; if (dir == DMA_DEV_TO_MEM) { chan = espi->dma_rx; sgt = &espi->rx_sgt; } else { chan = espi->dma_tx; sgt = &espi->tx_sgt; } dma_unmap_sg(chan->device->dev, sgt->sgl, sgt->nents, dir); } static void ep93xx_spi_dma_callback(void *callback_param) { complete(callback_param); } static void ep93xx_spi_dma_transfer(struct ep93xx_spi *espi) { struct spi_message *msg = espi->current_msg; struct dma_async_tx_descriptor *rxd, *txd; rxd = ep93xx_spi_dma_prepare(espi, DMA_DEV_TO_MEM); if (IS_ERR(rxd)) { dev_err(&espi->pdev->dev, "DMA RX failed: %ld\n", PTR_ERR(rxd)); msg->status = PTR_ERR(rxd); return; } txd = ep93xx_spi_dma_prepare(espi, DMA_MEM_TO_DEV); if (IS_ERR(txd)) { ep93xx_spi_dma_finish(espi, DMA_DEV_TO_MEM); dev_err(&espi->pdev->dev, "DMA TX failed: %ld\n", PTR_ERR(rxd)); msg->status = PTR_ERR(txd); return; } /* We are ready when RX is done */ rxd->callback = ep93xx_spi_dma_callback; rxd->callback_param = &espi->wait; /* Now submit both descriptors and wait while they finish */ dmaengine_submit(rxd); dmaengine_submit(txd); dma_async_issue_pending(espi->dma_rx); dma_async_issue_pending(espi->dma_tx); wait_for_completion(&espi->wait); ep93xx_spi_dma_finish(espi, DMA_MEM_TO_DEV); ep93xx_spi_dma_finish(espi, DMA_DEV_TO_MEM); } /** * ep93xx_spi_process_transfer() - processes one SPI transfer * @espi: ep93xx SPI controller struct * @msg: current message * @t: transfer to process * * This function processes one SPI transfer given in @t. Function waits until * transfer is complete (may sleep) and updates @msg->status based on whether * transfer was successfully processed or not. */ static void ep93xx_spi_process_transfer(struct ep93xx_spi *espi, struct spi_message *msg, struct spi_transfer *t) { struct ep93xx_spi_chip *chip = spi_get_ctldata(msg->spi); msg->state = t; /* * Handle any transfer specific settings if needed. We use * temporary chip settings here and restore original later when * the transfer is finished. */ if (t->speed_hz || t->bits_per_word) { struct ep93xx_spi_chip tmp_chip = *chip; if (t->speed_hz) { int err; err = ep93xx_spi_calc_divisors(espi, &tmp_chip, t->speed_hz); if (err) { dev_err(&espi->pdev->dev, "failed to adjust speed\n"); msg->status = err; return; } } if (t->bits_per_word) tmp_chip.dss = bits_per_word_to_dss(t->bits_per_word); /* * Set up temporary new hw settings for this transfer. */ ep93xx_spi_chip_setup(espi, &tmp_chip); } espi->rx = 0; espi->tx = 0; /* * There is no point of setting up DMA for the transfers which will * fit into the FIFO and can be transferred with a single interrupt. * So in these cases we will be using PIO and don't bother for DMA. */ if (espi->dma_rx && t->len > SPI_FIFO_SIZE) ep93xx_spi_dma_transfer(espi); else ep93xx_spi_pio_transfer(espi); /* * In case of error during transmit, we bail out from processing * the message. */ if (msg->status) return; msg->actual_length += t->len; /* * After this transfer is finished, perform any possible * post-transfer actions requested by the protocol driver. */ if (t->delay_usecs) { set_current_state(TASK_UNINTERRUPTIBLE); schedule_timeout(usecs_to_jiffies(t->delay_usecs)); } if (t->cs_change) { if (!list_is_last(&t->transfer_list, &msg->transfers)) { /* * In case protocol driver is asking us to drop the * chipselect briefly, we let the scheduler to handle * any "delay" here. */ ep93xx_spi_cs_control(msg->spi, false); cond_resched(); ep93xx_spi_cs_control(msg->spi, true); } } if (t->speed_hz || t->bits_per_word) ep93xx_spi_chip_setup(espi, chip); } /* * ep93xx_spi_process_message() - process one SPI message * @espi: ep93xx SPI controller struct * @msg: message to process * * This function processes a single SPI message. We go through all transfers in * the message and pass them to ep93xx_spi_process_transfer(). Chipselect is * asserted during the whole message (unless per transfer cs_change is set). * * @msg->status contains %0 in case of success or negative error code in case of * failure. */ static void ep93xx_spi_process_message(struct ep93xx_spi *espi, struct spi_message *msg) { unsigned long timeout; struct spi_transfer *t; int err; /* * Enable the SPI controller and its clock. */ err = ep93xx_spi_enable(espi); if (err) { dev_err(&espi->pdev->dev, "failed to enable SPI controller\n"); msg->status = err; return; } /* * Just to be sure: flush any data from RX FIFO. */ timeout = jiffies + msecs_to_jiffies(SPI_TIMEOUT); while (ep93xx_spi_read_u16(espi, SSPSR) & SSPSR_RNE) { if (time_after(jiffies, timeout)) { dev_warn(&espi->pdev->dev, "timeout while flushing RX FIFO\n"); msg->status = -ETIMEDOUT; return; } ep93xx_spi_read_u16(espi, SSPDR); } /* * We explicitly handle FIFO level. This way we don't have to check TX * FIFO status using %SSPSR_TNF bit which may cause RX FIFO overruns. */ espi->fifo_level = 0; /* * Update SPI controller registers according to spi device and assert * the chipselect. */ ep93xx_spi_chip_setup(espi, spi_get_ctldata(msg->spi)); ep93xx_spi_cs_control(msg->spi, true); list_for_each_entry(t, &msg->transfers, transfer_list) { ep93xx_spi_process_transfer(espi, msg, t); if (msg->status) break; } /* * Now the whole message is transferred (or failed for some reason). We * deselect the device and disable the SPI controller. */ ep93xx_spi_cs_control(msg->spi, false); ep93xx_spi_disable(espi); } #define work_to_espi(work) (container_of((work), struct ep93xx_spi, msg_work)) /** * ep93xx_spi_work() - EP93xx SPI workqueue worker function * @work: work struct * * Workqueue worker function. This function is called when there are new * SPI messages to be processed. Message is taken out from the queue and then * passed to ep93xx_spi_process_message(). * * After message is transferred, protocol driver is notified by calling * @msg->complete(). In case of error, @msg->status is set to negative error * number, otherwise it contains zero (and @msg->actual_length is updated). */ static void ep93xx_spi_work(struct work_struct *work) { struct ep93xx_spi *espi = work_to_espi(work); struct spi_message *msg; spin_lock_irq(&espi->lock); if (!espi->running || espi->current_msg || list_empty(&espi->msg_queue)) { spin_unlock_irq(&espi->lock); return; } msg = list_first_entry(&espi->msg_queue, struct spi_message, queue); list_del_init(&msg->queue); espi->current_msg = msg; spin_unlock_irq(&espi->lock); ep93xx_spi_process_message(espi, msg); /* * Update the current message and re-schedule ourselves if there are * more messages in the queue. */ spin_lock_irq(&espi->lock); espi->current_msg = NULL; if (espi->running && !list_empty(&espi->msg_queue)) queue_work(espi->wq, &espi->msg_work); spin_unlock_irq(&espi->lock); /* notify the protocol driver that we are done with this message */ msg->complete(msg->context); } static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id) { struct ep93xx_spi *espi = dev_id; u8 irq_status = ep93xx_spi_read_u8(espi, SSPIIR); /* * If we got ROR (receive overrun) interrupt we know that something is * wrong. Just abort the message. */ if (unlikely(irq_status & SSPIIR_RORIS)) { /* clear the overrun interrupt */ ep93xx_spi_write_u8(espi, SSPICR, 0); dev_warn(&espi->pdev->dev, "receive overrun, aborting the message\n"); espi->current_msg->status = -EIO; } else { /* * Interrupt is either RX (RIS) or TX (TIS). For both cases we * simply execute next data transfer. */ if (ep93xx_spi_read_write(espi)) { /* * In normal case, there still is some processing left * for current transfer. Let's wait for the next * interrupt then. */ return IRQ_HANDLED; } } /* * Current transfer is finished, either with error or with success. In * any case we disable interrupts and notify the worker to handle * any post-processing of the message. */ ep93xx_spi_disable_interrupts(espi); complete(&espi->wait); return IRQ_HANDLED; } static bool ep93xx_spi_dma_filter(struct dma_chan *chan, void *filter_param) { if (ep93xx_dma_chan_is_m2p(chan)) return false; chan->private = filter_param; return true; } static int ep93xx_spi_setup_dma(struct ep93xx_spi *espi) { dma_cap_mask_t mask; int ret; espi->zeropage = (void *)get_zeroed_page(GFP_KERNEL); if (!espi->zeropage) return -ENOMEM; dma_cap_zero(mask); dma_cap_set(DMA_SLAVE, mask); espi->dma_rx_data.port = EP93XX_DMA_SSP; espi->dma_rx_data.direction = DMA_DEV_TO_MEM; espi->dma_rx_data.name = "ep93xx-spi-rx"; espi->dma_rx = dma_request_channel(mask, ep93xx_spi_dma_filter, &espi->dma_rx_data); if (!espi->dma_rx) { ret = -ENODEV; goto fail_free_page; } espi->dma_tx_data.port = EP93XX_DMA_SSP; espi->dma_tx_data.direction = DMA_MEM_TO_DEV; espi->dma_tx_data.name = "ep93xx-spi-tx"; espi->dma_tx = dma_request_channel(mask, ep93xx_spi_dma_filter, &espi->dma_tx_data); if (!espi->dma_tx) { ret = -ENODEV; goto fail_release_rx; } return 0; fail_release_rx: dma_release_channel(espi->dma_rx); espi->dma_rx = NULL; fail_free_page: free_page((unsigned long)espi->zeropage); return ret; } static void ep93xx_spi_release_dma(struct ep93xx_spi *espi) { if (espi->dma_rx) { dma_release_channel(espi->dma_rx); sg_free_table(&espi->rx_sgt); } if (espi->dma_tx) { dma_release_channel(espi->dma_tx); sg_free_table(&espi->tx_sgt); } if (espi->zeropage) free_page((unsigned long)espi->zeropage); } static int ep93xx_spi_probe(struct platform_device *pdev) { struct spi_master *master; struct ep93xx_spi_info *info; struct ep93xx_spi *espi; struct resource *res; int irq; int error; info = pdev->dev.platform_data; master = spi_alloc_master(&pdev->dev, sizeof(*espi)); if (!master) { dev_err(&pdev->dev, "failed to allocate spi master\n"); return -ENOMEM; } master->setup = ep93xx_spi_setup; master->transfer = ep93xx_spi_transfer; master->cleanup = ep93xx_spi_cleanup; master->bus_num = pdev->id; master->num_chipselect = info->num_chipselect; master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; platform_set_drvdata(pdev, master); espi = spi_master_get_devdata(master); espi->clk = clk_get(&pdev->dev, NULL); if (IS_ERR(espi->clk)) { dev_err(&pdev->dev, "unable to get spi clock\n"); error = PTR_ERR(espi->clk); goto fail_release_master; } spin_lock_init(&espi->lock); init_completion(&espi->wait); /* * Calculate maximum and minimum supported clock rates * for the controller. */ espi->max_rate = clk_get_rate(espi->clk) / 2; espi->min_rate = clk_get_rate(espi->clk) / (254 * 256); espi->pdev = pdev; irq = platform_get_irq(pdev, 0); if (irq < 0) { error = -EBUSY; dev_err(&pdev->dev, "failed to get irq resources\n"); goto fail_put_clock; } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { dev_err(&pdev->dev, "unable to get iomem resource\n"); error = -ENODEV; goto fail_put_clock; } espi->sspdr_phys = res->start + SSPDR; espi->regs_base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(espi->regs_base)) { error = PTR_ERR(espi->regs_base); goto fail_put_clock; } error = devm_request_irq(&pdev->dev, irq, ep93xx_spi_interrupt, 0, "ep93xx-spi", espi); if (error) { dev_err(&pdev->dev, "failed to request irq\n"); goto fail_put_clock; } if (info->use_dma && ep93xx_spi_setup_dma(espi)) dev_warn(&pdev->dev, "DMA setup failed. Falling back to PIO\n"); espi->wq = create_singlethread_workqueue("ep93xx_spid"); if (!espi->wq) { dev_err(&pdev->dev, "unable to create workqueue\n"); goto fail_free_dma; } INIT_WORK(&espi->msg_work, ep93xx_spi_work); INIT_LIST_HEAD(&espi->msg_queue); espi->running = true; /* make sure that the hardware is disabled */ ep93xx_spi_write_u8(espi, SSPCR1, 0); error = spi_register_master(master); if (error) { dev_err(&pdev->dev, "failed to register SPI master\n"); goto fail_free_queue; } dev_info(&pdev->dev, "EP93xx SPI Controller at 0x%08lx irq %d\n", (unsigned long)res->start, irq); return 0; fail_free_queue: destroy_workqueue(espi->wq); fail_free_dma: ep93xx_spi_release_dma(espi); fail_put_clock: clk_put(espi->clk); fail_release_master: spi_master_put(master); platform_set_drvdata(pdev, NULL); return error; } static int ep93xx_spi_remove(struct platform_device *pdev) { struct spi_master *master = platform_get_drvdata(pdev); struct ep93xx_spi *espi = spi_master_get_devdata(master); spin_lock_irq(&espi->lock); espi->running = false; spin_unlock_irq(&espi->lock); destroy_workqueue(espi->wq); /* * Complete remaining messages with %-ESHUTDOWN status. */ spin_lock_irq(&espi->lock); while (!list_empty(&espi->msg_queue)) { struct spi_message *msg; msg = list_first_entry(&espi->msg_queue, struct spi_message, queue); list_del_init(&msg->queue); msg->status = -ESHUTDOWN; spin_unlock_irq(&espi->lock); msg->complete(msg->context); spin_lock_irq(&espi->lock); } spin_unlock_irq(&espi->lock); ep93xx_spi_release_dma(espi); clk_put(espi->clk); platform_set_drvdata(pdev, NULL); spi_unregister_master(master); return 0; } static struct platform_driver ep93xx_spi_driver = { .driver = { .name = "ep93xx-spi", .owner = THIS_MODULE, }, .probe = ep93xx_spi_probe, .remove = ep93xx_spi_remove, }; module_platform_driver(ep93xx_spi_driver); MODULE_DESCRIPTION("EP93xx SPI Controller driver"); MODULE_AUTHOR("Mika Westerberg "); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:ep93xx-spi");