diff options
Diffstat (limited to 'ANDROID_3.4.5/drivers/spi/spi-ep93xx.c')
| -rw-r--r-- | ANDROID_3.4.5/drivers/spi/spi-ep93xx.c | 1207 |
1 files changed, 0 insertions, 1207 deletions
diff --git a/ANDROID_3.4.5/drivers/spi/spi-ep93xx.c b/ANDROID_3.4.5/drivers/spi/spi-ep93xx.c deleted file mode 100644 index e8055073..00000000 --- a/ANDROID_3.4.5/drivers/spi/spi-ep93xx.c +++ /dev/null @@ -1,1207 +0,0 @@ -/* - * 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 <linux/io.h> -#include <linux/clk.h> -#include <linux/err.h> -#include <linux/delay.h> -#include <linux/device.h> -#include <linux/dmaengine.h> -#include <linux/bitops.h> -#include <linux/interrupt.h> -#include <linux/module.h> -#include <linux/platform_device.h> -#include <linux/workqueue.h> -#include <linux/sched.h> -#include <linux/scatterlist.h> -#include <linux/spi/spi.h> - -#include <mach/dma.h> -#include <mach/ep93xx_spi.h> - -#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 - * @irq: IRQ number used by the driver - * @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; - int irq; - 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 __devinit ep93xx_spi_probe(struct platform_device *pdev) -{ - struct spi_master *master; - struct ep93xx_spi_info *info; - struct ep93xx_spi *espi; - struct resource *res; - 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; - - espi->irq = platform_get_irq(pdev, 0); - if (espi->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; - } - - res = request_mem_region(res->start, resource_size(res), pdev->name); - if (!res) { - dev_err(&pdev->dev, "unable to request iomem resources\n"); - error = -EBUSY; - goto fail_put_clock; - } - - espi->sspdr_phys = res->start + SSPDR; - espi->regs_base = ioremap(res->start, resource_size(res)); - if (!espi->regs_base) { - dev_err(&pdev->dev, "failed to map resources\n"); - error = -ENODEV; - goto fail_free_mem; - } - - error = request_irq(espi->irq, ep93xx_spi_interrupt, 0, - "ep93xx-spi", espi); - if (error) { - dev_err(&pdev->dev, "failed to request irq\n"); - goto fail_unmap_regs; - } - - 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, espi->irq); - - return 0; - -fail_free_queue: - destroy_workqueue(espi->wq); -fail_free_dma: - ep93xx_spi_release_dma(espi); - free_irq(espi->irq, espi); -fail_unmap_regs: - iounmap(espi->regs_base); -fail_free_mem: - release_mem_region(res->start, resource_size(res)); -fail_put_clock: - clk_put(espi->clk); -fail_release_master: - spi_master_put(master); - platform_set_drvdata(pdev, NULL); - - return error; -} - -static int __devexit ep93xx_spi_remove(struct platform_device *pdev) -{ - struct spi_master *master = platform_get_drvdata(pdev); - struct ep93xx_spi *espi = spi_master_get_devdata(master); - struct resource *res; - - 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); - free_irq(espi->irq, espi); - iounmap(espi->regs_base); - res = platform_get_resource(pdev, IORESOURCE_MEM, 0); - release_mem_region(res->start, resource_size(res)); - 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 = __devexit_p(ep93xx_spi_remove), -}; -module_platform_driver(ep93xx_spi_driver); - -MODULE_DESCRIPTION("EP93xx SPI Controller driver"); -MODULE_AUTHOR("Mika Westerberg <mika.westerberg@iki.fi>"); -MODULE_LICENSE("GPL"); -MODULE_ALIAS("platform:ep93xx-spi"); |