diff options
Diffstat (limited to 'drivers/spi/spi-mpc512x-psc.c')
| -rw-r--r-- | drivers/spi/spi-mpc512x-psc.c | 485 |
1 files changed, 265 insertions, 220 deletions
diff --git a/drivers/spi/spi-mpc512x-psc.c b/drivers/spi/spi-mpc512x-psc.c index 4c63f772780..577d23a1276 100644 --- a/drivers/spi/spi-mpc512x-psc.c +++ b/drivers/spi/spi-mpc512x-psc.c @@ -16,40 +16,33 @@ #include <linux/module.h> #include <linux/kernel.h> -#include <linux/init.h> #include <linux/errno.h> #include <linux/interrupt.h> #include <linux/of_address.h> +#include <linux/of_irq.h> #include <linux/of_platform.h> -#include <linux/workqueue.h> #include <linux/completion.h> #include <linux/io.h> #include <linux/delay.h> #include <linux/clk.h> #include <linux/spi/spi.h> #include <linux/fsl_devices.h> +#include <linux/gpio.h> #include <asm/mpc52xx_psc.h> struct mpc512x_psc_spi { void (*cs_control)(struct spi_device *spi, bool on); - u32 sysclk; /* driver internal data */ struct mpc52xx_psc __iomem *psc; struct mpc512x_psc_fifo __iomem *fifo; unsigned int irq; u8 bits_per_word; - u8 busy; - u32 mclk; - u8 eofbyte; + struct clk *clk_mclk; + struct clk *clk_ipg; + u32 mclk_rate; - struct workqueue_struct *workqueue; - struct work_struct work; - - struct list_head queue; - spinlock_t lock; /* Message queue lock */ - - struct completion done; + struct completion txisrdone; }; /* controller state */ @@ -81,6 +74,7 @@ static void mpc512x_psc_spi_activate_cs(struct spi_device *spi) struct mpc52xx_psc __iomem *psc = mps->psc; u32 sicr; u32 ccr; + int speed; u16 bclkdiv; sicr = in_be32(&psc->sicr); @@ -104,16 +98,16 @@ static void mpc512x_psc_spi_activate_cs(struct spi_device *spi) ccr = in_be32(&psc->ccr); ccr &= 0xFF000000; - if (cs->speed_hz) - bclkdiv = (mps->mclk / cs->speed_hz) - 1; - else - bclkdiv = (mps->mclk / 1000000) - 1; /* default 1MHz */ + speed = cs->speed_hz; + if (!speed) + speed = 1000000; /* default 1MHz */ + bclkdiv = (mps->mclk_rate / speed) - 1; ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8)); out_be32(&psc->ccr, ccr); mps->bits_per_word = cs->bits_per_word; - if (mps->cs_control) + if (mps->cs_control && gpio_is_valid(spi->cs_gpio)) mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 1 : 0); } @@ -121,7 +115,7 @@ static void mpc512x_psc_spi_deactivate_cs(struct spi_device *spi) { struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master); - if (mps->cs_control) + if (mps->cs_control && gpio_is_valid(spi->cs_gpio)) mps->cs_control(spi, (spi->mode & SPI_CS_HIGH) ? 0 : 1); } @@ -135,149 +129,225 @@ static int mpc512x_psc_spi_transfer_rxtx(struct spi_device *spi, struct spi_transfer *t) { struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master); - struct mpc52xx_psc __iomem *psc = mps->psc; struct mpc512x_psc_fifo __iomem *fifo = mps->fifo; - size_t len = t->len; + size_t tx_len = t->len; + size_t rx_len = t->len; u8 *tx_buf = (u8 *)t->tx_buf; u8 *rx_buf = (u8 *)t->rx_buf; if (!tx_buf && !rx_buf && t->len) return -EINVAL; - /* Zero MR2 */ - in_8(&psc->mode); - out_8(&psc->mode, 0x0); - - while (len) { - int count; - int i; + while (rx_len || tx_len) { + size_t txcount; u8 data; size_t fifosz; - int rxcount; + size_t rxcount; + int rxtries; /* - * The number of bytes that can be sent at a time - * depends on the fifo size. + * send the TX bytes in as large a chunk as possible + * but neither exceed the TX nor the RX FIFOs */ fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->txsz)); - count = min(fifosz, len); - - for (i = count; i > 0; i--) { - data = tx_buf ? *tx_buf++ : 0; - if (len == EOFBYTE) - setbits32(&fifo->txcmd, MPC512x_PSC_FIFO_EOF); - out_8(&fifo->txdata_8, data); - len--; - } - - INIT_COMPLETION(mps->done); - - /* interrupt on tx fifo empty */ - out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY); - out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY); - - /* enable transmiter/receiver */ - out_8(&psc->command, - MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE); + txcount = min(fifosz, tx_len); + fifosz = MPC512x_PSC_FIFO_SZ(in_be32(&fifo->rxsz)); + fifosz -= in_be32(&fifo->rxcnt) + 1; + txcount = min(fifosz, txcount); + if (txcount) { + + /* fill the TX FIFO */ + while (txcount-- > 0) { + data = tx_buf ? *tx_buf++ : 0; + if (tx_len == EOFBYTE && t->cs_change) + setbits32(&fifo->txcmd, + MPC512x_PSC_FIFO_EOF); + out_8(&fifo->txdata_8, data); + tx_len--; + } - wait_for_completion(&mps->done); + /* have the ISR trigger when the TX FIFO is empty */ + reinit_completion(&mps->txisrdone); + out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY); + out_be32(&fifo->tximr, MPC512x_PSC_FIFO_EMPTY); + wait_for_completion(&mps->txisrdone); + } - mdelay(1); + /* + * consume as much RX data as the FIFO holds, while we + * iterate over the transfer's TX data length + * + * only insist in draining all the remaining RX bytes + * when the TX bytes were exhausted (that's at the very + * end of this transfer, not when still iterating over + * the transfer's chunks) + */ + rxtries = 50; + do { + + /* + * grab whatever was in the FIFO when we started + * looking, don't bother fetching what was added to + * the FIFO while we read from it -- we'll return + * here eventually and prefer sending out remaining + * TX data + */ + fifosz = in_be32(&fifo->rxcnt); + rxcount = min(fifosz, rx_len); + while (rxcount-- > 0) { + data = in_8(&fifo->rxdata_8); + if (rx_buf) + *rx_buf++ = data; + rx_len--; + } - /* rx fifo should have count bytes in it */ - rxcount = in_be32(&fifo->rxcnt); - if (rxcount != count) - mdelay(1); + /* + * come back later if there still is TX data to send, + * bail out of the RX drain loop if all of the TX data + * was sent and all of the RX data was received (i.e. + * when the transmission has completed) + */ + if (tx_len) + break; + if (!rx_len) + break; - rxcount = in_be32(&fifo->rxcnt); - if (rxcount != count) { - dev_warn(&spi->dev, "expected %d bytes in rx fifo " - "but got %d\n", count, rxcount); + /* + * TX data transmission has completed while RX data + * is still pending -- that's a transient situation + * which depends on wire speed and specific + * hardware implementation details (buffering) yet + * should resolve very quickly + * + * just yield for a moment to not hog the CPU for + * too long when running SPI at low speed + * + * the timeout range is rather arbitrary and tries + * to balance throughput against system load; the + * chosen values result in a minimal timeout of 50 + * times 10us and thus work at speeds as low as + * some 20kbps, while the maximum timeout at the + * transfer's end could be 5ms _if_ nothing else + * ticks in the system _and_ RX data still wasn't + * received, which only occurs in situations that + * are exceptional; removing the unpredictability + * of the timeout either decreases throughput + * (longer timeouts), or puts more load on the + * system (fixed short timeouts) or requires the + * use of a timeout API instead of a counter and an + * unknown inner delay + */ + usleep_range(10, 100); + + } while (--rxtries > 0); + if (!tx_len && rx_len && !rxtries) { + /* + * not enough RX bytes even after several retries + * and the resulting rather long timeout? + */ + rxcount = in_be32(&fifo->rxcnt); + dev_warn(&spi->dev, + "short xfer, missing %zd RX bytes, FIFO level %zd\n", + rx_len, rxcount); } - rxcount = min(rxcount, count); - for (i = rxcount; i > 0; i--) { - data = in_8(&fifo->rxdata_8); - if (rx_buf) - *rx_buf++ = data; - } - while (in_be32(&fifo->rxcnt)) { - in_8(&fifo->rxdata_8); + /* + * drain and drop RX data which "should not be there" in + * the first place, for undisturbed transmission this turns + * into a NOP (except for the FIFO level fetch) + */ + if (!tx_len && !rx_len) { + while (in_be32(&fifo->rxcnt)) + in_8(&fifo->rxdata_8); } - out_8(&psc->command, - MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE); } - /* disable transmiter/receiver and fifo interrupt */ - out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE); - out_be32(&fifo->tximr, 0); return 0; } -static void mpc512x_psc_spi_work(struct work_struct *work) +static int mpc512x_psc_spi_msg_xfer(struct spi_master *master, + struct spi_message *m) { - struct mpc512x_psc_spi *mps = container_of(work, - struct mpc512x_psc_spi, - work); - - spin_lock_irq(&mps->lock); - mps->busy = 1; - while (!list_empty(&mps->queue)) { - struct spi_message *m; - struct spi_device *spi; - struct spi_transfer *t = NULL; - unsigned cs_change; - int status; - - m = container_of(mps->queue.next, struct spi_message, queue); - list_del_init(&m->queue); - spin_unlock_irq(&mps->lock); - - spi = m->spi; - cs_change = 1; - status = 0; - list_for_each_entry(t, &m->transfers, transfer_list) { - if (t->bits_per_word || t->speed_hz) { - status = mpc512x_psc_spi_transfer_setup(spi, t); - if (status < 0) - break; - } + struct spi_device *spi; + unsigned cs_change; + int status; + struct spi_transfer *t; + + spi = m->spi; + cs_change = 1; + status = 0; + list_for_each_entry(t, &m->transfers, transfer_list) { + if (t->bits_per_word || t->speed_hz) { + status = mpc512x_psc_spi_transfer_setup(spi, t); + if (status < 0) + break; + } - if (cs_change) - mpc512x_psc_spi_activate_cs(spi); - cs_change = t->cs_change; + if (cs_change) + mpc512x_psc_spi_activate_cs(spi); + cs_change = t->cs_change; - status = mpc512x_psc_spi_transfer_rxtx(spi, t); - if (status) - break; - m->actual_length += t->len; + status = mpc512x_psc_spi_transfer_rxtx(spi, t); + if (status) + break; + m->actual_length += t->len; - if (t->delay_usecs) - udelay(t->delay_usecs); + if (t->delay_usecs) + udelay(t->delay_usecs); - if (cs_change) - mpc512x_psc_spi_deactivate_cs(spi); - } + if (cs_change) + mpc512x_psc_spi_deactivate_cs(spi); + } - m->status = status; + m->status = status; + if (m->complete) m->complete(m->context); - if (status || !cs_change) - mpc512x_psc_spi_deactivate_cs(spi); + if (status || !cs_change) + mpc512x_psc_spi_deactivate_cs(spi); - mpc512x_psc_spi_transfer_setup(spi, NULL); + mpc512x_psc_spi_transfer_setup(spi, NULL); - spin_lock_irq(&mps->lock); - } - mps->busy = 0; - spin_unlock_irq(&mps->lock); + spi_finalize_current_message(master); + return status; +} + +static int mpc512x_psc_spi_prep_xfer_hw(struct spi_master *master) +{ + struct mpc512x_psc_spi *mps = spi_master_get_devdata(master); + struct mpc52xx_psc __iomem *psc = mps->psc; + + dev_dbg(&master->dev, "%s()\n", __func__); + + /* Zero MR2 */ + in_8(&psc->mode); + out_8(&psc->mode, 0x0); + + /* enable transmitter/receiver */ + out_8(&psc->command, MPC52xx_PSC_TX_ENABLE | MPC52xx_PSC_RX_ENABLE); + + return 0; +} + +static int mpc512x_psc_spi_unprep_xfer_hw(struct spi_master *master) +{ + struct mpc512x_psc_spi *mps = spi_master_get_devdata(master); + struct mpc52xx_psc __iomem *psc = mps->psc; + struct mpc512x_psc_fifo __iomem *fifo = mps->fifo; + + dev_dbg(&master->dev, "%s()\n", __func__); + + /* disable transmitter/receiver and fifo interrupt */ + out_8(&psc->command, MPC52xx_PSC_TX_DISABLE | MPC52xx_PSC_RX_DISABLE); + out_be32(&fifo->tximr, 0); + + return 0; } static int mpc512x_psc_spi_setup(struct spi_device *spi) { - struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master); struct mpc512x_psc_spi_cs *cs = spi->controller_state; - unsigned long flags; + int ret; if (spi->bits_per_word % 8) return -EINVAL; @@ -286,39 +356,32 @@ static int mpc512x_psc_spi_setup(struct spi_device *spi) cs = kzalloc(sizeof *cs, GFP_KERNEL); if (!cs) return -ENOMEM; + + if (gpio_is_valid(spi->cs_gpio)) { + ret = gpio_request(spi->cs_gpio, dev_name(&spi->dev)); + if (ret) { + dev_err(&spi->dev, "can't get CS gpio: %d\n", + ret); + kfree(cs); + return ret; + } + gpio_direction_output(spi->cs_gpio, + spi->mode & SPI_CS_HIGH ? 0 : 1); + } + spi->controller_state = cs; } cs->bits_per_word = spi->bits_per_word; cs->speed_hz = spi->max_speed_hz; - spin_lock_irqsave(&mps->lock, flags); - if (!mps->busy) - mpc512x_psc_spi_deactivate_cs(spi); - spin_unlock_irqrestore(&mps->lock, flags); - - return 0; -} - -static int mpc512x_psc_spi_transfer(struct spi_device *spi, - struct spi_message *m) -{ - struct mpc512x_psc_spi *mps = spi_master_get_devdata(spi->master); - unsigned long flags; - - m->actual_length = 0; - m->status = -EINPROGRESS; - - spin_lock_irqsave(&mps->lock, flags); - list_add_tail(&m->queue, &mps->queue); - queue_work(mps->workqueue, &mps->work); - spin_unlock_irqrestore(&mps->lock, flags); - return 0; } static void mpc512x_psc_spi_cleanup(struct spi_device *spi) { + if (gpio_is_valid(spi->cs_gpio)) + gpio_free(spi->cs_gpio); kfree(spi->controller_state); } @@ -327,19 +390,11 @@ static int mpc512x_psc_spi_port_config(struct spi_master *master, { struct mpc52xx_psc __iomem *psc = mps->psc; struct mpc512x_psc_fifo __iomem *fifo = mps->fifo; - struct clk *spiclk; - int ret = 0; - char name[32]; u32 sicr; u32 ccr; + int speed; u16 bclkdiv; - sprintf(name, "psc%d_mclk", master->bus_num); - spiclk = clk_get(&master->dev, name); - clk_enable(spiclk); - mps->mclk = clk_get_rate(spiclk); - clk_put(spiclk); - /* Reset the PSC into a known state */ out_8(&psc->command, MPC52xx_PSC_RST_RX); out_8(&psc->command, MPC52xx_PSC_RST_TX); @@ -366,7 +421,8 @@ static int mpc512x_psc_spi_port_config(struct spi_master *master, ccr = in_be32(&psc->ccr); ccr &= 0xFF000000; - bclkdiv = (mps->mclk / 1000000) - 1; /* default 1MHz */ + speed = 1000000; /* default 1MHz */ + bclkdiv = (mps->mclk_rate / speed) - 1; ccr |= (((bclkdiv & 0xff) << 16) | (((bclkdiv >> 8) & 0xff) << 8)); out_be32(&psc->ccr, ccr); @@ -386,7 +442,7 @@ static int mpc512x_psc_spi_port_config(struct spi_master *master, mps->bits_per_word = 8; - return ret; + return 0; } static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id) @@ -394,27 +450,31 @@ static irqreturn_t mpc512x_psc_spi_isr(int irq, void *dev_id) struct mpc512x_psc_spi *mps = (struct mpc512x_psc_spi *)dev_id; struct mpc512x_psc_fifo __iomem *fifo = mps->fifo; - /* clear interrupt and wake up the work queue */ + /* clear interrupt and wake up the rx/tx routine */ if (in_be32(&fifo->txisr) & in_be32(&fifo->tximr) & MPC512x_PSC_FIFO_EMPTY) { out_be32(&fifo->txisr, MPC512x_PSC_FIFO_EMPTY); out_be32(&fifo->tximr, 0); - complete(&mps->done); + complete(&mps->txisrdone); return IRQ_HANDLED; } return IRQ_NONE; } -/* bus_num is used only for the case dev->platform_data == NULL */ -static int __devinit mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr, - u32 size, unsigned int irq, - s16 bus_num) +static void mpc512x_spi_cs_control(struct spi_device *spi, bool onoff) +{ + gpio_set_value(spi->cs_gpio, onoff); +} + +static int mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr, + u32 size, unsigned int irq) { - struct fsl_spi_platform_data *pdata = dev->platform_data; + struct fsl_spi_platform_data *pdata = dev_get_platdata(dev); struct mpc512x_psc_spi *mps; struct spi_master *master; int ret; void *tempp; + struct clk *clk; master = spi_alloc_master(dev, sizeof *mps); if (master == NULL) @@ -425,25 +485,22 @@ static int __devinit mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr, mps->irq = irq; if (pdata == NULL) { - dev_err(dev, "probe called without platform data, no " - "cs_control function will be called\n"); - mps->cs_control = NULL; - mps->sysclk = 0; - master->bus_num = bus_num; - master->num_chipselect = 255; + mps->cs_control = mpc512x_spi_cs_control; } else { mps->cs_control = pdata->cs_control; - mps->sysclk = pdata->sysclk; master->bus_num = pdata->bus_num; master->num_chipselect = pdata->max_chipselect; } + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH | SPI_LSB_FIRST; master->setup = mpc512x_psc_spi_setup; - master->transfer = mpc512x_psc_spi_transfer; + master->prepare_transfer_hardware = mpc512x_psc_spi_prep_xfer_hw; + master->transfer_one_message = mpc512x_psc_spi_msg_xfer; + master->unprepare_transfer_hardware = mpc512x_psc_spi_unprep_xfer_hw; master->cleanup = mpc512x_psc_spi_cleanup; master->dev.of_node = dev->of_node; - tempp = ioremap(regaddr, size); + tempp = devm_ioremap(dev, regaddr, size); if (!tempp) { dev_err(dev, "could not ioremap I/O port range\n"); ret = -EFAULT; @@ -452,66 +509,68 @@ static int __devinit mpc512x_psc_spi_do_probe(struct device *dev, u32 regaddr, mps->psc = tempp; mps->fifo = (struct mpc512x_psc_fifo *)(tempp + sizeof(struct mpc52xx_psc)); + ret = devm_request_irq(dev, mps->irq, mpc512x_psc_spi_isr, IRQF_SHARED, + "mpc512x-psc-spi", mps); + if (ret) + goto free_master; + init_completion(&mps->txisrdone); - ret = request_irq(mps->irq, mpc512x_psc_spi_isr, IRQF_SHARED, - "mpc512x-psc-spi", mps); + clk = devm_clk_get(dev, "mclk"); + if (IS_ERR(clk)) { + ret = PTR_ERR(clk); + goto free_master; + } + ret = clk_prepare_enable(clk); if (ret) goto free_master; + mps->clk_mclk = clk; + mps->mclk_rate = clk_get_rate(clk); + + clk = devm_clk_get(dev, "ipg"); + if (IS_ERR(clk)) { + ret = PTR_ERR(clk); + goto free_mclk_clock; + } + ret = clk_prepare_enable(clk); + if (ret) + goto free_mclk_clock; + mps->clk_ipg = clk; ret = mpc512x_psc_spi_port_config(master, mps); if (ret < 0) - goto free_irq; - - spin_lock_init(&mps->lock); - init_completion(&mps->done); - INIT_WORK(&mps->work, mpc512x_psc_spi_work); - INIT_LIST_HEAD(&mps->queue); - - mps->workqueue = - create_singlethread_workqueue(dev_name(master->dev.parent)); - if (mps->workqueue == NULL) { - ret = -EBUSY; - goto free_irq; - } + goto free_ipg_clock; - ret = spi_register_master(master); + ret = devm_spi_register_master(dev, master); if (ret < 0) - goto unreg_master; + goto free_ipg_clock; return ret; -unreg_master: - destroy_workqueue(mps->workqueue); -free_irq: - free_irq(mps->irq, mps); +free_ipg_clock: + clk_disable_unprepare(mps->clk_ipg); +free_mclk_clock: + clk_disable_unprepare(mps->clk_mclk); free_master: - if (mps->psc) - iounmap(mps->psc); spi_master_put(master); return ret; } -static int __devexit mpc512x_psc_spi_do_remove(struct device *dev) +static int mpc512x_psc_spi_do_remove(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct mpc512x_psc_spi *mps = spi_master_get_devdata(master); - flush_workqueue(mps->workqueue); - destroy_workqueue(mps->workqueue); - spi_unregister_master(master); - free_irq(mps->irq, mps); - if (mps->psc) - iounmap(mps->psc); + clk_disable_unprepare(mps->clk_mclk); + clk_disable_unprepare(mps->clk_ipg); return 0; } -static int __devinit mpc512x_psc_spi_of_probe(struct platform_device *op) +static int mpc512x_psc_spi_of_probe(struct platform_device *op) { const u32 *regaddr_p; u64 regaddr64, size64; - s16 id = -1; regaddr_p = of_get_address(op->dev.of_node, 0, &size64, NULL); if (!regaddr_p) { @@ -520,25 +579,11 @@ static int __devinit mpc512x_psc_spi_of_probe(struct platform_device *op) } regaddr64 = of_translate_address(op->dev.of_node, regaddr_p); - /* get PSC id (0..11, used by port_config) */ - if (op->dev.platform_data == NULL) { - const u32 *psc_nump; - - psc_nump = of_get_property(op->dev.of_node, "cell-index", NULL); - if (!psc_nump || *psc_nump > 11) { - dev_err(&op->dev, "mpc512x_psc_spi: Device node %s " - "has invalid cell-index property\n", - op->dev.of_node->full_name); - return -EINVAL; - } - id = *psc_nump; - } - return mpc512x_psc_spi_do_probe(&op->dev, (u32) regaddr64, (u32) size64, - irq_of_parse_and_map(op->dev.of_node, 0), id); + irq_of_parse_and_map(op->dev.of_node, 0)); } -static int __devexit mpc512x_psc_spi_of_remove(struct platform_device *op) +static int mpc512x_psc_spi_of_remove(struct platform_device *op) { return mpc512x_psc_spi_do_remove(&op->dev); } @@ -552,7 +597,7 @@ MODULE_DEVICE_TABLE(of, mpc512x_psc_spi_of_match); static struct platform_driver mpc512x_psc_spi_of_driver = { .probe = mpc512x_psc_spi_of_probe, - .remove = __devexit_p(mpc512x_psc_spi_of_remove), + .remove = mpc512x_psc_spi_of_remove, .driver = { .name = "mpc512x-psc-spi", .owner = THIS_MODULE, |
