/* * Freescale MXS SPI master driver * * Copyright 2012 DENX Software Engineering, GmbH. * Copyright 2012 Freescale Semiconductor, Inc. * Copyright 2008 Embedded Alley Solutions, Inc All Rights Reserved. * * Rework and transition to new API by: * Marek Vasut * * Based on previous attempt by: * Fabio Estevam * * Based on code from U-Boot bootloader by: * Marek Vasut * * Based on spi-stmp.c, which is: * Author: Dmitry Pervushin * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define DRIVER_NAME "mxs-spi" /* Use 10S timeout for very long transfers, it should suffice. */ #define SSP_TIMEOUT 10000 #define SG_MAXLEN 0xff00 struct mxs_spi { struct mxs_ssp ssp; struct completion c; }; static int mxs_spi_setup_transfer(struct spi_device *dev, struct spi_transfer *t) { struct mxs_spi *spi = spi_master_get_devdata(dev->master); struct mxs_ssp *ssp = &spi->ssp; uint8_t bits_per_word; uint32_t hz = 0; bits_per_word = dev->bits_per_word; if (t && t->bits_per_word) bits_per_word = t->bits_per_word; hz = dev->max_speed_hz; if (t && t->speed_hz) hz = min(hz, t->speed_hz); if (hz == 0) { dev_err(&dev->dev, "Cannot continue with zero clock\n"); return -EINVAL; } mxs_ssp_set_clk_rate(ssp, hz); writel(BF_SSP_CTRL1_SSP_MODE(BV_SSP_CTRL1_SSP_MODE__SPI) | BF_SSP_CTRL1_WORD_LENGTH (BV_SSP_CTRL1_WORD_LENGTH__EIGHT_BITS) | ((dev->mode & SPI_CPOL) ? BM_SSP_CTRL1_POLARITY : 0) | ((dev->mode & SPI_CPHA) ? BM_SSP_CTRL1_PHASE : 0), ssp->base + HW_SSP_CTRL1(ssp)); writel(0x0, ssp->base + HW_SSP_CMD0); writel(0x0, ssp->base + HW_SSP_CMD1); return 0; } static int mxs_spi_setup(struct spi_device *dev) { int err = 0; if (!dev->bits_per_word) dev->bits_per_word = 8; if (dev->mode & ~(SPI_CPOL | SPI_CPHA)) return -EINVAL; err = mxs_spi_setup_transfer(dev, NULL); if (err) { dev_err(&dev->dev, "Failed to setup transfer, error = %d\n", err); } return err; } static uint32_t mxs_spi_cs_to_reg(unsigned cs) { uint32_t select = 0; /* * i.MX28 Datasheet: 17.10.1: HW_SSP_CTRL0 * * The bits BM_SSP_CTRL0_WAIT_FOR_CMD and BM_SSP_CTRL0_WAIT_FOR_IRQ * in HW_SSP_CTRL0 register do have multiple usage, please refer to * the datasheet for further details. In SPI mode, they are used to * toggle the chip-select lines (nCS pins). */ if (cs & 1) select |= BM_SSP_CTRL0_WAIT_FOR_CMD; if (cs & 2) select |= BM_SSP_CTRL0_WAIT_FOR_IRQ; return select; } static void mxs_spi_set_cs(struct mxs_spi *spi, unsigned cs) { const uint32_t mask = BM_SSP_CTRL0_WAIT_FOR_CMD | BM_SSP_CTRL0_WAIT_FOR_IRQ; uint32_t select; struct mxs_ssp *ssp = &spi->ssp; writel(mask, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); select = mxs_spi_cs_to_reg(cs); writel(select, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); } static inline void mxs_spi_enable(struct mxs_spi *spi) { struct mxs_ssp *ssp = &spi->ssp; writel(BM_SSP_CTRL0_LOCK_CS, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); writel(BM_SSP_CTRL0_IGNORE_CRC, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); } static inline void mxs_spi_disable(struct mxs_spi *spi) { struct mxs_ssp *ssp = &spi->ssp; writel(BM_SSP_CTRL0_LOCK_CS, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); writel(BM_SSP_CTRL0_IGNORE_CRC, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); } static int mxs_ssp_wait(struct mxs_spi *spi, int offset, int mask, bool set) { const unsigned long timeout = jiffies + msecs_to_jiffies(SSP_TIMEOUT); struct mxs_ssp *ssp = &spi->ssp; uint32_t reg; do { reg = readl_relaxed(ssp->base + offset); if (!set) reg = ~reg; reg &= mask; if (reg == mask) return 0; } while (time_before(jiffies, timeout)); return -ETIMEDOUT; } static void mxs_ssp_dma_irq_callback(void *param) { struct mxs_spi *spi = param; complete(&spi->c); } static irqreturn_t mxs_ssp_irq_handler(int irq, void *dev_id) { struct mxs_ssp *ssp = dev_id; dev_err(ssp->dev, "%s[%i] CTRL1=%08x STATUS=%08x\n", __func__, __LINE__, readl(ssp->base + HW_SSP_CTRL1(ssp)), readl(ssp->base + HW_SSP_STATUS(ssp))); return IRQ_HANDLED; } static int mxs_spi_txrx_dma(struct mxs_spi *spi, int cs, unsigned char *buf, int len, int *first, int *last, int write) { struct mxs_ssp *ssp = &spi->ssp; struct dma_async_tx_descriptor *desc = NULL; const bool vmalloced_buf = is_vmalloc_addr(buf); const int desc_len = vmalloced_buf ? PAGE_SIZE : SG_MAXLEN; const int sgs = DIV_ROUND_UP(len, desc_len); int sg_count; int min, ret; uint32_t ctrl0; struct page *vm_page; void *sg_buf; struct { uint32_t pio[4]; struct scatterlist sg; } *dma_xfer; if (!len) return -EINVAL; dma_xfer = kzalloc(sizeof(*dma_xfer) * sgs, GFP_KERNEL); if (!dma_xfer) return -ENOMEM; INIT_COMPLETION(spi->c); ctrl0 = readl(ssp->base + HW_SSP_CTRL0); ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT; ctrl0 |= BM_SSP_CTRL0_DATA_XFER | mxs_spi_cs_to_reg(cs); if (*first) ctrl0 |= BM_SSP_CTRL0_LOCK_CS; if (!write) ctrl0 |= BM_SSP_CTRL0_READ; /* Queue the DMA data transfer. */ for (sg_count = 0; sg_count < sgs; sg_count++) { min = min(len, desc_len); /* Prepare the transfer descriptor. */ if ((sg_count + 1 == sgs) && *last) ctrl0 |= BM_SSP_CTRL0_IGNORE_CRC; if (ssp->devid == IMX23_SSP) { ctrl0 &= ~BM_SSP_CTRL0_XFER_COUNT; ctrl0 |= min; } dma_xfer[sg_count].pio[0] = ctrl0; dma_xfer[sg_count].pio[3] = min; if (vmalloced_buf) { vm_page = vmalloc_to_page(buf); if (!vm_page) { ret = -ENOMEM; goto err_vmalloc; } sg_buf = page_address(vm_page) + ((size_t)buf & ~PAGE_MASK); } else { sg_buf = buf; } sg_init_one(&dma_xfer[sg_count].sg, sg_buf, min); ret = dma_map_sg(ssp->dev, &dma_xfer[sg_count].sg, 1, write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); len -= min; buf += min; /* Queue the PIO register write transfer. */ desc = dmaengine_prep_slave_sg(ssp->dmach, (struct scatterlist *)dma_xfer[sg_count].pio, (ssp->devid == IMX23_SSP) ? 1 : 4, DMA_TRANS_NONE, sg_count ? DMA_PREP_INTERRUPT : 0); if (!desc) { dev_err(ssp->dev, "Failed to get PIO reg. write descriptor.\n"); ret = -EINVAL; goto err_mapped; } desc = dmaengine_prep_slave_sg(ssp->dmach, &dma_xfer[sg_count].sg, 1, write ? DMA_MEM_TO_DEV : DMA_DEV_TO_MEM, DMA_PREP_INTERRUPT | DMA_CTRL_ACK); if (!desc) { dev_err(ssp->dev, "Failed to get DMA data write descriptor.\n"); ret = -EINVAL; goto err_mapped; } } /* * The last descriptor must have this callback, * to finish the DMA transaction. */ desc->callback = mxs_ssp_dma_irq_callback; desc->callback_param = spi; /* Start the transfer. */ dmaengine_submit(desc); dma_async_issue_pending(ssp->dmach); ret = wait_for_completion_timeout(&spi->c, msecs_to_jiffies(SSP_TIMEOUT)); if (!ret) { dev_err(ssp->dev, "DMA transfer timeout\n"); ret = -ETIMEDOUT; dmaengine_terminate_all(ssp->dmach); goto err_vmalloc; } ret = 0; err_vmalloc: while (--sg_count >= 0) { err_mapped: dma_unmap_sg(ssp->dev, &dma_xfer[sg_count].sg, 1, write ? DMA_TO_DEVICE : DMA_FROM_DEVICE); } kfree(dma_xfer); return ret; } static int mxs_spi_txrx_pio(struct mxs_spi *spi, int cs, unsigned char *buf, int len, int *first, int *last, int write) { struct mxs_ssp *ssp = &spi->ssp; if (*first) mxs_spi_enable(spi); mxs_spi_set_cs(spi, cs); while (len--) { if (*last && len == 0) mxs_spi_disable(spi); if (ssp->devid == IMX23_SSP) { writel(BM_SSP_CTRL0_XFER_COUNT, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); writel(1, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); } else { writel(1, ssp->base + HW_SSP_XFER_SIZE); } if (write) writel(BM_SSP_CTRL0_READ, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_CLR); else writel(BM_SSP_CTRL0_READ, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); writel(BM_SSP_CTRL0_RUN, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 1)) return -ETIMEDOUT; if (write) writel(*buf, ssp->base + HW_SSP_DATA(ssp)); writel(BM_SSP_CTRL0_DATA_XFER, ssp->base + HW_SSP_CTRL0 + STMP_OFFSET_REG_SET); if (!write) { if (mxs_ssp_wait(spi, HW_SSP_STATUS(ssp), BM_SSP_STATUS_FIFO_EMPTY, 0)) return -ETIMEDOUT; *buf = (readl(ssp->base + HW_SSP_DATA(ssp)) & 0xff); } if (mxs_ssp_wait(spi, HW_SSP_CTRL0, BM_SSP_CTRL0_RUN, 0)) return -ETIMEDOUT; buf++; } if (len <= 0) return 0; return -ETIMEDOUT; } static int mxs_spi_transfer_one(struct spi_master *master, struct spi_message *m) { struct mxs_spi *spi = spi_master_get_devdata(master); struct mxs_ssp *ssp = &spi->ssp; int first, last; struct spi_transfer *t, *tmp_t; int status = 0; int cs; first = last = 0; cs = m->spi->chip_select; list_for_each_entry_safe(t, tmp_t, &m->transfers, transfer_list) { status = mxs_spi_setup_transfer(m->spi, t); if (status) break; if (&t->transfer_list == m->transfers.next) first = 1; if (&t->transfer_list == m->transfers.prev) last = 1; if ((t->rx_buf && t->tx_buf) || (t->rx_dma && t->tx_dma)) { dev_err(ssp->dev, "Cannot send and receive simultaneously\n"); status = -EINVAL; break; } /* * Small blocks can be transfered via PIO. * Measured by empiric means: * * dd if=/dev/mtdblock0 of=/dev/null bs=1024k count=1 * * DMA only: 2.164808 seconds, 473.0KB/s * Combined: 1.676276 seconds, 610.9KB/s */ if (t->len < 32) { writel(BM_SSP_CTRL1_DMA_ENABLE, ssp->base + HW_SSP_CTRL1(ssp) + STMP_OFFSET_REG_CLR); if (t->tx_buf) status = mxs_spi_txrx_pio(spi, cs, (void *)t->tx_buf, t->len, &first, &last, 1); if (t->rx_buf) status = mxs_spi_txrx_pio(spi, cs, t->rx_buf, t->len, &first, &last, 0); } else { writel(BM_SSP_CTRL1_DMA_ENABLE, ssp->base + HW_SSP_CTRL1(ssp) + STMP_OFFSET_REG_SET); if (t->tx_buf) status = mxs_spi_txrx_dma(spi, cs, (void *)t->tx_buf, t->len, &first, &last, 1); if (t->rx_buf) status = mxs_spi_txrx_dma(spi, cs, t->rx_buf, t->len, &first, &last, 0); } if (status) { stmp_reset_block(ssp->base); break; } m->actual_length += t->len; first = last = 0; } m->status = status; spi_finalize_current_message(master); return status; } static const struct of_device_id mxs_spi_dt_ids[] = { { .compatible = "fsl,imx23-spi", .data = (void *) IMX23_SSP, }, { .compatible = "fsl,imx28-spi", .data = (void *) IMX28_SSP, }, { /* sentinel */ } }; MODULE_DEVICE_TABLE(of, mxs_spi_dt_ids); static int mxs_spi_probe(struct platform_device *pdev) { const struct of_device_id *of_id = of_match_device(mxs_spi_dt_ids, &pdev->dev); struct device_node *np = pdev->dev.of_node; struct spi_master *master; struct mxs_spi *spi; struct mxs_ssp *ssp; struct resource *iores; struct clk *clk; void __iomem *base; int devid, clk_freq; int ret = 0, irq_err; /* * Default clock speed for the SPI core. 160MHz seems to * work reasonably well with most SPI flashes, so use this * as a default. Override with "clock-frequency" DT prop. */ const int clk_freq_default = 160000000; iores = platform_get_resource(pdev, IORESOURCE_MEM, 0); irq_err = platform_get_irq(pdev, 0); if (!iores || irq_err < 0) return -EINVAL; base = devm_ioremap_resource(&pdev->dev, iores); if (IS_ERR(base)) return PTR_ERR(base); clk = devm_clk_get(&pdev->dev, NULL); if (IS_ERR(clk)) return PTR_ERR(clk); devid = (enum mxs_ssp_id) of_id->data; ret = of_property_read_u32(np, "clock-frequency", &clk_freq); if (ret) clk_freq = clk_freq_default; master = spi_alloc_master(&pdev->dev, sizeof(*spi)); if (!master) return -ENOMEM; master->transfer_one_message = mxs_spi_transfer_one; master->setup = mxs_spi_setup; master->bits_per_word_mask = SPI_BPW_MASK(8); master->mode_bits = SPI_CPOL | SPI_CPHA; master->num_chipselect = 3; master->dev.of_node = np; master->flags = SPI_MASTER_HALF_DUPLEX; spi = spi_master_get_devdata(master); ssp = &spi->ssp; ssp->dev = &pdev->dev; ssp->clk = clk; ssp->base = base; ssp->devid = devid; init_completion(&spi->c); ret = devm_request_irq(&pdev->dev, irq_err, mxs_ssp_irq_handler, 0, DRIVER_NAME, ssp); if (ret) goto out_master_free; ssp->dmach = dma_request_slave_channel(&pdev->dev, "rx-tx"); if (!ssp->dmach) { dev_err(ssp->dev, "Failed to request DMA\n"); ret = -ENODEV; goto out_master_free; } clk_prepare_enable(ssp->clk); clk_set_rate(ssp->clk, clk_freq); ssp->clk_rate = clk_get_rate(ssp->clk) / 1000; stmp_reset_block(ssp->base); platform_set_drvdata(pdev, master); ret = spi_register_master(master); if (ret) { dev_err(&pdev->dev, "Cannot register SPI master, %d\n", ret); goto out_free_dma; } return 0; out_free_dma: clk_disable_unprepare(ssp->clk); dma_release_channel(ssp->dmach); out_master_free: spi_master_put(master); return ret; } static int mxs_spi_remove(struct platform_device *pdev) { struct spi_master *master; struct mxs_spi *spi; struct mxs_ssp *ssp; master = spi_master_get(platform_get_drvdata(pdev)); spi = spi_master_get_devdata(master); ssp = &spi->ssp; spi_unregister_master(master); clk_disable_unprepare(ssp->clk); dma_release_channel(ssp->dmach); spi_master_put(master); return 0; } static struct platform_driver mxs_spi_driver = { .probe = mxs_spi_probe, .remove = mxs_spi_remove, .driver = { .name = DRIVER_NAME, .owner = THIS_MODULE, .of_match_table = mxs_spi_dt_ids, }, }; module_platform_driver(mxs_spi_driver); MODULE_AUTHOR("Marek Vasut "); MODULE_DESCRIPTION("MXS SPI master driver"); MODULE_LICENSE("GPL"); MODULE_ALIAS("platform:mxs-spi");