| Author | Tokens | Token Proportion | Commits | Commit Proportion |
|---|---|---|---|---|
| Mika Westerberg | 2107 | 65.76% | 3 | 9.68% |
| H Hartley Sweeten | 975 | 30.43% | 14 | 45.16% |
| Nathan Chancellor | 48 | 1.50% | 1 | 3.23% |
| Axel Lin | 15 | 0.47% | 1 | 3.23% |
| Hannu Heikkinen | 11 | 0.34% | 1 | 3.23% |
| Stephen Warren | 11 | 0.34% | 1 | 3.23% |
| Jingoo Han | 10 | 0.31% | 2 | 6.45% |
| Thierry Reding | 8 | 0.25% | 1 | 3.23% |
| Grant C. Likely | 6 | 0.19% | 1 | 3.23% |
| Kees Cook | 5 | 0.16% | 1 | 3.23% |
| Vinod Koul | 2 | 0.06% | 1 | 3.23% |
| Arnd Bergmann | 2 | 0.06% | 1 | 3.23% |
| Jarkko Nikula | 2 | 0.06% | 1 | 3.23% |
| Fabio Estevam | 1 | 0.03% | 1 | 3.23% |
| Alex Bounine | 1 | 0.03% | 1 | 3.23% |
| Total | 3204 | 31 |
/* * 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/sched.h> #include <linux/scatterlist.h> #include <linux/gpio.h> #include <linux/spi/spi.h> #include <linux/platform_data/dma-ep93xx.h> #include <linux/platform_data/spi-ep93xx.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 * @clk: clock for the controller * @mmio: pointer to ioremap()'d registers * @sspdr_phys: physical address of the SSPDR register * @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 */ struct ep93xx_spi { struct clk *clk; void __iomem *mmio; unsigned long sspdr_phys; 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; }; /* converts bits per word to CR0.DSS value */ #define bits_per_word_to_dss(bpw) ((bpw) - 1) /** * ep93xx_spi_calc_divisors() - calculates SPI clock divisors * @master: SPI master * @rate: desired SPI output clock rate * @div_cpsr: pointer to return the cpsr (pre-scaler) divider * @div_scr: pointer to return the scr divider */ static int ep93xx_spi_calc_divisors(struct spi_master *master, u32 rate, u8 *div_cpsr, u8 *div_scr) { struct ep93xx_spi *espi = spi_master_get_devdata(master); 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. */ rate = clamp(rate, master->min_speed_hz, master->max_speed_hz); /* * 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) { *div_scr = (u8)scr; *div_cpsr = (u8)cpsr; return 0; } } } return -EINVAL; } static int ep93xx_spi_chip_setup(struct spi_master *master, struct spi_device *spi, struct spi_transfer *xfer) { struct ep93xx_spi *espi = spi_master_get_devdata(master); u8 dss = bits_per_word_to_dss(xfer->bits_per_word); u8 div_cpsr = 0; u8 div_scr = 0; u16 cr0; int err; err = ep93xx_spi_calc_divisors(master, xfer->speed_hz, &div_cpsr, &div_scr); if (err) return err; cr0 = div_scr << SSPCR0_SCR_SHIFT; cr0 |= (spi->mode & (SPI_CPHA | SPI_CPOL)) << SSPCR0_MODE_SHIFT; cr0 |= dss; dev_dbg(&master->dev, "setup: mode %d, cpsr %d, scr %d, dss %d\n", spi->mode, div_cpsr, div_scr, dss); dev_dbg(&master->dev, "setup: cr0 %#x\n", cr0); writel(div_cpsr, espi->mmio + SSPCPSR); writel(cr0, espi->mmio + SSPCR0); return 0; } static void ep93xx_do_write(struct spi_master *master) { struct ep93xx_spi *espi = spi_master_get_devdata(master); struct spi_transfer *xfer = master->cur_msg->state; u32 val = 0; if (xfer->bits_per_word > 8) { if (xfer->tx_buf) val = ((u16 *)xfer->tx_buf)[espi->tx]; espi->tx += 2; } else { if (xfer->tx_buf) val = ((u8 *)xfer->tx_buf)[espi->tx]; espi->tx += 1; } writel(val, espi->mmio + SSPDR); } static void ep93xx_do_read(struct spi_master *master) { struct ep93xx_spi *espi = spi_master_get_devdata(master); struct spi_transfer *xfer = master->cur_msg->state; u32 val; val = readl(espi->mmio + SSPDR); if (xfer->bits_per_word > 8) { if (xfer->rx_buf) ((u16 *)xfer->rx_buf)[espi->rx] = val; espi->rx += 2; } else { if (xfer->rx_buf) ((u8 *)xfer->rx_buf)[espi->rx] = val; espi->rx += 1; } } /** * 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 spi_master *master) { struct ep93xx_spi *espi = spi_master_get_devdata(master); struct spi_transfer *xfer = master->cur_msg->state; /* read as long as RX FIFO has frames in it */ while ((readl(espi->mmio + SSPSR) & SSPSR_RNE)) { ep93xx_do_read(master); espi->fifo_level--; } /* write as long as TX FIFO has room */ while (espi->fifo_level < SPI_FIFO_SIZE && espi->tx < xfer->len) { ep93xx_do_write(master); espi->fifo_level++; } if (espi->rx == xfer->len) return 0; return -EINPROGRESS; } static enum dma_transfer_direction ep93xx_dma_data_to_trans_dir(enum dma_data_direction dir) { switch (dir) { case DMA_TO_DEVICE: return DMA_MEM_TO_DEV; case DMA_FROM_DEVICE: return DMA_DEV_TO_MEM; default: return DMA_TRANS_NONE; } } /** * ep93xx_spi_dma_prepare() - prepares a DMA transfer * @master: SPI master * @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 spi_master *master, enum dma_data_direction dir) { struct ep93xx_spi *espi = spi_master_get_devdata(master); struct spi_transfer *xfer = master->cur_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 = xfer->len; int i, ret, nents; if (xfer->bits_per_word > 8) buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES; else buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE; memset(&conf, 0, sizeof(conf)); conf.direction = ep93xx_dma_data_to_trans_dir(dir); if (dir == DMA_FROM_DEVICE) { chan = espi->dma_rx; buf = xfer->rx_buf; sgt = &espi->rx_sgt; conf.src_addr = espi->sspdr_phys; conf.src_addr_width = buswidth; } else { chan = espi->dma_tx; buf = xfer->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(&master->dev, "len = %zu expected 0!\n", 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, conf.direction, 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 * @master: SPI master * @dir: DMA transfer direction * * Function finishes with the DMA transfer. After this, the DMA buffer is * unmapped. */ static void ep93xx_spi_dma_finish(struct spi_master *master, enum dma_data_direction dir) { struct ep93xx_spi *espi = spi_master_get_devdata(master); struct dma_chan *chan; struct sg_table *sgt; if (dir == DMA_FROM_DEVICE) { 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) { struct spi_master *master = callback_param; ep93xx_spi_dma_finish(master, DMA_TO_DEVICE); ep93xx_spi_dma_finish(master, DMA_FROM_DEVICE); spi_finalize_current_transfer(master); } static int ep93xx_spi_dma_transfer(struct spi_master *master) { struct ep93xx_spi *espi = spi_master_get_devdata(master); struct dma_async_tx_descriptor *rxd, *txd; rxd = ep93xx_spi_dma_prepare(master, DMA_FROM_DEVICE); if (IS_ERR(rxd)) { dev_err(&master->dev, "DMA RX failed: %ld\n", PTR_ERR(rxd)); return PTR_ERR(rxd); } txd = ep93xx_spi_dma_prepare(master, DMA_TO_DEVICE); if (IS_ERR(txd)) { ep93xx_spi_dma_finish(master, DMA_FROM_DEVICE); dev_err(&master->dev, "DMA TX failed: %ld\n", PTR_ERR(txd)); return PTR_ERR(txd); } /* We are ready when RX is done */ rxd->callback = ep93xx_spi_dma_callback; rxd->callback_param = master; /* Now submit both descriptors and start DMA */ dmaengine_submit(rxd); dmaengine_submit(txd); dma_async_issue_pending(espi->dma_rx); dma_async_issue_pending(espi->dma_tx); /* signal that we need to wait for completion */ return 1; } static irqreturn_t ep93xx_spi_interrupt(int irq, void *dev_id) { struct spi_master *master = dev_id; struct ep93xx_spi *espi = spi_master_get_devdata(master); u32 val; /* * If we got ROR (receive overrun) interrupt we know that something is * wrong. Just abort the message. */ if (readl(espi->mmio + SSPIIR) & SSPIIR_RORIS) { /* clear the overrun interrupt */ writel(0, espi->mmio + SSPICR); dev_warn(&master->dev, "receive overrun, aborting the message\n"); master->cur_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(master)) { /* * 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. */ val = readl(espi->mmio + SSPCR1); val &= ~(SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE); writel(val, espi->mmio + SSPCR1); spi_finalize_current_transfer(master); return IRQ_HANDLED; } static int ep93xx_spi_transfer_one(struct spi_master *master, struct spi_device *spi, struct spi_transfer *xfer) { struct ep93xx_spi *espi = spi_master_get_devdata(master); u32 val; int ret; ret = ep93xx_spi_chip_setup(master, spi, xfer); if (ret) { dev_err(&master->dev, "failed to setup chip for transfer\n"); return ret; } master->cur_msg->state = xfer; 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 && xfer->len > SPI_FIFO_SIZE) return ep93xx_spi_dma_transfer(master); /* Using PIO so prime the TX FIFO and enable interrupts */ ep93xx_spi_read_write(master); val = readl(espi->mmio + SSPCR1); val |= (SSPCR1_RORIE | SSPCR1_TIE | SSPCR1_RIE); writel(val, espi->mmio + SSPCR1); /* signal that we need to wait for completion */ return 1; } static int ep93xx_spi_prepare_message(struct spi_master *master, struct spi_message *msg) { struct ep93xx_spi *espi = spi_master_get_devdata(master); unsigned long timeout; /* * Just to be sure: flush any data from RX FIFO. */ timeout = jiffies + msecs_to_jiffies(SPI_TIMEOUT); while (readl(espi->mmio + SSPSR) & SSPSR_RNE) { if (time_after(jiffies, timeout)) { dev_warn(&master->dev, "timeout while flushing RX FIFO\n"); return -ETIMEDOUT; } readl(espi->mmio + 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; return 0; } static int ep93xx_spi_prepare_hardware(struct spi_master *master) { struct ep93xx_spi *espi = spi_master_get_devdata(master); u32 val; int ret; ret = clk_enable(espi->clk); if (ret) return ret; val = readl(espi->mmio + SSPCR1); val |= SSPCR1_SSE; writel(val, espi->mmio + SSPCR1); return 0; } static int ep93xx_spi_unprepare_hardware(struct spi_master *master) { struct ep93xx_spi *espi = spi_master_get_devdata(master); u32 val; val = readl(espi->mmio + SSPCR1); val &= ~SSPCR1_SSE; writel(val, espi->mmio + SSPCR1); clk_disable(espi->clk); return 0; } 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; int i; info = dev_get_platdata(&pdev->dev); if (!info) { dev_err(&pdev->dev, "missing platform data\n"); return -EINVAL; } irq = platform_get_irq(pdev, 0); if (irq < 0) { dev_err(&pdev->dev, "failed to get irq resources\n"); return -EBUSY; } res = platform_get_resource(pdev, IORESOURCE_MEM, 0); if (!res) { dev_err(&pdev->dev, "unable to get iomem resource\n"); return -ENODEV; } master = spi_alloc_master(&pdev->dev, sizeof(*espi)); if (!master) return -ENOMEM; master->prepare_transfer_hardware = ep93xx_spi_prepare_hardware; master->unprepare_transfer_hardware = ep93xx_spi_unprepare_hardware; master->prepare_message = ep93xx_spi_prepare_message; master->transfer_one = ep93xx_spi_transfer_one; master->bus_num = pdev->id; master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH; master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16); master->num_chipselect = info->num_chipselect; master->cs_gpios = devm_kcalloc(&master->dev, master->num_chipselect, sizeof(int), GFP_KERNEL); if (!master->cs_gpios) { error = -ENOMEM; goto fail_release_master; } for (i = 0; i < master->num_chipselect; i++) { master->cs_gpios[i] = info->chipselect[i]; if (!gpio_is_valid(master->cs_gpios[i])) continue; error = devm_gpio_request_one(&pdev->dev, master->cs_gpios[i], GPIOF_OUT_INIT_HIGH, "ep93xx-spi"); if (error) { dev_err(&pdev->dev, "could not request cs gpio %d\n", master->cs_gpios[i]); goto fail_release_master; } } platform_set_drvdata(pdev, master); espi = spi_master_get_devdata(master); espi->clk = devm_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; } /* * Calculate maximum and minimum supported clock rates * for the controller. */ master->max_speed_hz = clk_get_rate(espi->clk) / 2; master->min_speed_hz = clk_get_rate(espi->clk) / (254 * 256); espi->sspdr_phys = res->start + SSPDR; espi->mmio = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(espi->mmio)) { error = PTR_ERR(espi->mmio); goto fail_release_master; } error = devm_request_irq(&pdev->dev, irq, ep93xx_spi_interrupt, 0, "ep93xx-spi", master); if (error) { dev_err(&pdev->dev, "failed to request irq\n"); goto fail_release_master; } if (info->use_dma && ep93xx_spi_setup_dma(espi)) dev_warn(&pdev->dev, "DMA setup failed. Falling back to PIO\n"); /* make sure that the hardware is disabled */ writel(0, espi->mmio + SSPCR1); error = devm_spi_register_master(&pdev->dev, master); if (error) { dev_err(&pdev->dev, "failed to register SPI master\n"); goto fail_free_dma; } dev_info(&pdev->dev, "EP93xx SPI Controller at 0x%08lx irq %d\n", (unsigned long)res->start, irq); return 0; fail_free_dma: ep93xx_spi_release_dma(espi); fail_release_master: spi_master_put(master); 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); ep93xx_spi_release_dma(espi); return 0; } static struct platform_driver ep93xx_spi_driver = { .driver = { .name = "ep93xx-spi", }, .probe = ep93xx_spi_probe, .remove = 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");
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