/* * PIC32 Quad SPI controller driver. * * Purna Chandra Mandal <purna.mandal@microchip.com> * Copyright (c) 2016, Microchip Technology Inc. * * This program is free software; you can distribute it and/or modify it * under the terms of the GNU General Public License (Version 2) as * published by the Free Software Foundation. * * This program is distributed in the hope 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 <linux/clk.h> #include <linux/dma-mapping.h> #include <linux/interrupt.h> #include <linux/io.h> #include <linux/iopoll.h> #include <linux/module.h> #include <linux/of.h> #include <linux/platform_device.h> #include <linux/slab.h> #include <linux/spi/spi.h> /* SQI registers */ #define PESQI_XIP_CONF1_REG 0x00 #define PESQI_XIP_CONF2_REG 0x04 #define PESQI_CONF_REG 0x08 #define PESQI_CTRL_REG 0x0C #define PESQI_CLK_CTRL_REG 0x10 #define PESQI_CMD_THRES_REG 0x14 #define PESQI_INT_THRES_REG 0x18 #define PESQI_INT_ENABLE_REG 0x1C #define PESQI_INT_STAT_REG 0x20 #define PESQI_TX_DATA_REG 0x24 #define PESQI_RX_DATA_REG 0x28 #define PESQI_STAT1_REG 0x2C #define PESQI_STAT2_REG 0x30 #define PESQI_BD_CTRL_REG 0x34 #define PESQI_BD_CUR_ADDR_REG 0x38 #define PESQI_BD_BASE_ADDR_REG 0x40 #define PESQI_BD_STAT_REG 0x44 #define PESQI_BD_POLL_CTRL_REG 0x48 #define PESQI_BD_TX_DMA_STAT_REG 0x4C #define PESQI_BD_RX_DMA_STAT_REG 0x50 #define PESQI_THRES_REG 0x54 #define PESQI_INT_SIGEN_REG 0x58 /* PESQI_CONF_REG fields */ #define PESQI_MODE 0x7 #define PESQI_MODE_BOOT 0 #define PESQI_MODE_PIO 1 #define PESQI_MODE_DMA 2 #define PESQI_MODE_XIP 3 #define PESQI_MODE_SHIFT 0 #define PESQI_CPHA BIT(3) #define PESQI_CPOL BIT(4) #define PESQI_LSBF BIT(5) #define PESQI_RXLATCH BIT(7) #define PESQI_SERMODE BIT(8) #define PESQI_WP_EN BIT(9) #define PESQI_HOLD_EN BIT(10) #define PESQI_BURST_EN BIT(12) #define PESQI_CS_CTRL_HW BIT(15) #define PESQI_SOFT_RESET BIT(16) #define PESQI_LANES_SHIFT 20 #define PESQI_SINGLE_LANE 0 #define PESQI_DUAL_LANE 1 #define PESQI_QUAD_LANE 2 #define PESQI_CSEN_SHIFT 24 #define PESQI_EN BIT(23) /* PESQI_CLK_CTRL_REG fields */ #define PESQI_CLK_EN BIT(0) #define PESQI_CLK_STABLE BIT(1) #define PESQI_CLKDIV_SHIFT 8 #define PESQI_CLKDIV 0xff /* PESQI_INT_THR/CMD_THR_REG */ #define PESQI_TXTHR_MASK 0x1f #define PESQI_TXTHR_SHIFT 8 #define PESQI_RXTHR_MASK 0x1f #define PESQI_RXTHR_SHIFT 0 /* PESQI_INT_EN/INT_STAT/INT_SIG_EN_REG */ #define PESQI_TXEMPTY BIT(0) #define PESQI_TXFULL BIT(1) #define PESQI_TXTHR BIT(2) #define PESQI_RXEMPTY BIT(3) #define PESQI_RXFULL BIT(4) #define PESQI_RXTHR BIT(5) #define PESQI_BDDONE BIT(9) /* BD processing complete */ #define PESQI_PKTCOMP BIT(10) /* packet processing complete */ #define PESQI_DMAERR BIT(11) /* error */ /* PESQI_BD_CTRL_REG */ #define PESQI_DMA_EN BIT(0) /* enable DMA engine */ #define PESQI_POLL_EN BIT(1) /* enable polling */ #define PESQI_BDP_START BIT(2) /* start BD processor */ /* PESQI controller buffer descriptor */ struct buf_desc { u32 bd_ctrl; /* control */ u32 bd_status; /* reserved */ u32 bd_addr; /* DMA buffer addr */ u32 bd_nextp; /* next item in chain */ }; /* bd_ctrl */ #define BD_BUFLEN 0x1ff #define BD_CBD_INT_EN BIT(16) /* Current BD is processed */ #define BD_PKT_INT_EN BIT(17) /* All BDs of PKT processed */ #define BD_LIFM BIT(18) /* last data of pkt */ #define BD_LAST BIT(19) /* end of list */ #define BD_DATA_RECV BIT(20) /* receive data */ #define BD_DDR BIT(21) /* DDR mode */ #define BD_DUAL BIT(22) /* Dual SPI */ #define BD_QUAD BIT(23) /* Quad SPI */ #define BD_LSBF BIT(25) /* LSB First */ #define BD_STAT_CHECK BIT(27) /* Status poll */ #define BD_DEVSEL_SHIFT 28 /* CS */ #define BD_CS_DEASSERT BIT(30) /* de-assert CS after current BD */ #define BD_EN BIT(31) /* BD owned by H/W */ /** * struct ring_desc - Representation of SQI ring descriptor * @list: list element to add to free or used list. * @bd: PESQI controller buffer descriptor * @bd_dma: DMA address of PESQI controller buffer descriptor * @xfer_len: transfer length */ struct ring_desc { struct list_head list; struct buf_desc *bd; dma_addr_t bd_dma; u32 xfer_len; }; /* Global constants */ #define PESQI_BD_BUF_LEN_MAX 256 #define PESQI_BD_COUNT 256 /* max 64KB data per spi message */ struct pic32_sqi { void __iomem *regs; struct clk *sys_clk; struct clk *base_clk; /* drives spi clock */ struct spi_master *master; int irq; struct completion xfer_done; struct ring_desc *ring; void *bd; dma_addr_t bd_dma; struct list_head bd_list_free; /* free */ struct list_head bd_list_used; /* allocated */ struct spi_device *cur_spi; u32 cur_speed; u8 cur_mode; }; static inline void pic32_setbits(void __iomem *reg, u32 set) { writel(readl(reg) | set, reg); } static inline void pic32_clrbits(void __iomem *reg, u32 clr) { writel(readl(reg) & ~clr, reg); } static int pic32_sqi_set_clk_rate(struct pic32_sqi *sqi, u32 sck) { u32 val, div; /* div = base_clk / (2 * spi_clk) */ div = clk_get_rate(sqi->base_clk) / (2 * sck); div &= PESQI_CLKDIV; val = readl(sqi->regs + PESQI_CLK_CTRL_REG); /* apply new divider */ val &= ~(PESQI_CLK_STABLE | (PESQI_CLKDIV << PESQI_CLKDIV_SHIFT)); val |= div << PESQI_CLKDIV_SHIFT; writel(val, sqi->regs + PESQI_CLK_CTRL_REG); /* wait for stability */ return readl_poll_timeout(sqi->regs + PESQI_CLK_CTRL_REG, val, val & PESQI_CLK_STABLE, 1, 5000); } static inline void pic32_sqi_enable_int(struct pic32_sqi *sqi) { u32 mask = PESQI_DMAERR | PESQI_BDDONE | PESQI_PKTCOMP; writel(mask, sqi->regs + PESQI_INT_ENABLE_REG); /* INT_SIGEN works as interrupt-gate to INTR line */ writel(mask, sqi->regs + PESQI_INT_SIGEN_REG); } static inline void pic32_sqi_disable_int(struct pic32_sqi *sqi) { writel(0, sqi->regs + PESQI_INT_ENABLE_REG); writel(0, sqi->regs + PESQI_INT_SIGEN_REG); } static irqreturn_t pic32_sqi_isr(int irq, void *dev_id) { struct pic32_sqi *sqi = dev_id; u32 enable, status; enable = readl(sqi->regs + PESQI_INT_ENABLE_REG); status = readl(sqi->regs + PESQI_INT_STAT_REG); /* check spurious interrupt */ if (!status) return IRQ_NONE; if (status & PESQI_DMAERR) { enable = 0; goto irq_done; } if (status & PESQI_TXTHR) enable &= ~(PESQI_TXTHR | PESQI_TXFULL | PESQI_TXEMPTY); if (status & PESQI_RXTHR) enable &= ~(PESQI_RXTHR | PESQI_RXFULL | PESQI_RXEMPTY); if (status & PESQI_BDDONE) enable &= ~PESQI_BDDONE; /* packet processing completed */ if (status & PESQI_PKTCOMP) { /* mask all interrupts */ enable = 0; /* complete trasaction */ complete(&sqi->xfer_done); } irq_done: /* interrupts are sticky, so mask when handled */ writel(enable, sqi->regs + PESQI_INT_ENABLE_REG); return IRQ_HANDLED; } static struct ring_desc *ring_desc_get(struct pic32_sqi *sqi) { struct ring_desc *rdesc; if (list_empty(&sqi->bd_list_free)) return NULL; rdesc = list_first_entry(&sqi->bd_list_free, struct ring_desc, list); list_del(&rdesc->list); list_add_tail(&rdesc->list, &sqi->bd_list_used); return rdesc; } static void ring_desc_put(struct pic32_sqi *sqi, struct ring_desc *rdesc) { list_del(&rdesc->list); list_add(&rdesc->list, &sqi->bd_list_free); } static int pic32_sqi_one_transfer(struct pic32_sqi *sqi, struct spi_message *mesg, struct spi_transfer *xfer) { struct spi_device *spi = mesg->spi; struct scatterlist *sg, *sgl; struct ring_desc *rdesc; struct buf_desc *bd; int nents, i; u32 bd_ctrl; u32 nbits; /* Device selection */ bd_ctrl = spi->chip_select << BD_DEVSEL_SHIFT; /* half-duplex: select transfer buffer, direction and lane */ if (xfer->rx_buf) { bd_ctrl |= BD_DATA_RECV; nbits = xfer->rx_nbits; sgl = xfer->rx_sg.sgl; nents = xfer->rx_sg.nents; } else { nbits = xfer->tx_nbits; sgl = xfer->tx_sg.sgl; nents = xfer->tx_sg.nents; } if (nbits & SPI_NBITS_QUAD) bd_ctrl |= BD_QUAD; else if (nbits & SPI_NBITS_DUAL) bd_ctrl |= BD_DUAL; /* LSB first */ if (spi->mode & SPI_LSB_FIRST) bd_ctrl |= BD_LSBF; /* ownership to hardware */ bd_ctrl |= BD_EN; for_each_sg(sgl, sg, nents, i) { /* get ring descriptor */ rdesc = ring_desc_get(sqi); if (!rdesc) break; bd = rdesc->bd; /* BD CTRL: length */ rdesc->xfer_len = sg_dma_len(sg); bd->bd_ctrl = bd_ctrl; bd->bd_ctrl |= rdesc->xfer_len; /* BD STAT */ bd->bd_status = 0; /* BD BUFFER ADDRESS */ bd->bd_addr = sg->dma_address; } return 0; } static int pic32_sqi_prepare_hardware(struct spi_master *master) { struct pic32_sqi *sqi = spi_master_get_devdata(master); /* enable spi interface */ pic32_setbits(sqi->regs + PESQI_CONF_REG, PESQI_EN); /* enable spi clk */ pic32_setbits(sqi->regs + PESQI_CLK_CTRL_REG, PESQI_CLK_EN); return 0; } static bool pic32_sqi_can_dma(struct spi_master *master, struct spi_device *spi, struct spi_transfer *x) { /* Do DMA irrespective of transfer size */ return true; } static int pic32_sqi_one_message(struct spi_master *master, struct spi_message *msg) { struct spi_device *spi = msg->spi; struct ring_desc *rdesc, *next; struct spi_transfer *xfer; struct pic32_sqi *sqi; int ret = 0, mode; u32 val; sqi = spi_master_get_devdata(master); reinit_completion(&sqi->xfer_done); msg->actual_length = 0; /* We can't handle spi_transfer specific "speed_hz", "bits_per_word" * and "delay_usecs". But spi_device specific speed and mode change * can be handled at best during spi chip-select switch. */ if (sqi->cur_spi != spi) { /* set spi speed */ if (sqi->cur_speed != spi->max_speed_hz) { sqi->cur_speed = spi->max_speed_hz; ret = pic32_sqi_set_clk_rate(sqi, spi->max_speed_hz); if (ret) dev_warn(&spi->dev, "set_clk, %d\n", ret); } /* set spi mode */ mode = spi->mode & (SPI_MODE_3 | SPI_LSB_FIRST); if (sqi->cur_mode != mode) { val = readl(sqi->regs + PESQI_CONF_REG); val &= ~(PESQI_CPOL | PESQI_CPHA | PESQI_LSBF); if (mode & SPI_CPOL) val |= PESQI_CPOL; if (mode & SPI_LSB_FIRST) val |= PESQI_LSBF; val |= PESQI_CPHA; writel(val, sqi->regs + PESQI_CONF_REG); sqi->cur_mode = mode; } sqi->cur_spi = spi; } /* prepare hardware desc-list(BD) for transfer(s) */ list_for_each_entry(xfer, &msg->transfers, transfer_list) { ret = pic32_sqi_one_transfer(sqi, msg, xfer); if (ret) { dev_err(&spi->dev, "xfer %p err\n", xfer); goto xfer_out; } } /* BDs are prepared and chained. Now mark LAST_BD, CS_DEASSERT at last * element of the list. */ rdesc = list_last_entry(&sqi->bd_list_used, struct ring_desc, list); rdesc->bd->bd_ctrl |= BD_LAST | BD_CS_DEASSERT | BD_LIFM | BD_PKT_INT_EN; /* set base address BD list for DMA engine */ rdesc = list_first_entry(&sqi->bd_list_used, struct ring_desc, list); writel(rdesc->bd_dma, sqi->regs + PESQI_BD_BASE_ADDR_REG); /* enable interrupt */ pic32_sqi_enable_int(sqi); /* enable DMA engine */ val = PESQI_DMA_EN | PESQI_POLL_EN | PESQI_BDP_START; writel(val, sqi->regs + PESQI_BD_CTRL_REG); /* wait for xfer completion */ ret = wait_for_completion_timeout(&sqi->xfer_done, 5 * HZ); if (ret <= 0) { dev_err(&sqi->master->dev, "wait timedout/interrupted\n"); ret = -EIO; msg->status = ret; } else { /* success */ msg->status = 0; ret = 0; } /* disable DMA */ writel(0, sqi->regs + PESQI_BD_CTRL_REG); pic32_sqi_disable_int(sqi); xfer_out: list_for_each_entry_safe_reverse(rdesc, next, &sqi->bd_list_used, list) { /* Update total byte transferred */ msg->actual_length += rdesc->xfer_len; /* release ring descr */ ring_desc_put(sqi, rdesc); } spi_finalize_current_message(spi->master); return ret; } static int pic32_sqi_unprepare_hardware(struct spi_master *master) { struct pic32_sqi *sqi = spi_master_get_devdata(master); /* disable clk */ pic32_clrbits(sqi->regs + PESQI_CLK_CTRL_REG, PESQI_CLK_EN); /* disable spi */ pic32_clrbits(sqi->regs + PESQI_CONF_REG, PESQI_EN); return 0; } static int ring_desc_ring_alloc(struct pic32_sqi *sqi) { struct ring_desc *rdesc; struct buf_desc *bd; int i; /* allocate coherent DMAable memory for hardware buffer descriptors. */ sqi->bd = dma_zalloc_coherent(&sqi->master->dev, sizeof(*bd) * PESQI_BD_COUNT, &sqi->bd_dma, GFP_DMA32); if (!sqi->bd) { dev_err(&sqi->master->dev, "failed allocating dma buffer\n"); return -ENOMEM; } /* allocate software ring descriptors */ sqi->ring = kcalloc(PESQI_BD_COUNT, sizeof(*rdesc), GFP_KERNEL); if (!sqi->ring) { dma_free_coherent(&sqi->master->dev, sizeof(*bd) * PESQI_BD_COUNT, sqi->bd, sqi->bd_dma); return -ENOMEM; } bd = (struct buf_desc *)sqi->bd; INIT_LIST_HEAD(&sqi->bd_list_free); INIT_LIST_HEAD(&sqi->bd_list_used); /* initialize ring-desc */ for (i = 0, rdesc = sqi->ring; i < PESQI_BD_COUNT; i++, rdesc++) { INIT_LIST_HEAD(&rdesc->list); rdesc->bd = &bd[i]; rdesc->bd_dma = sqi->bd_dma + (void *)&bd[i] - (void *)bd; list_add_tail(&rdesc->list, &sqi->bd_list_free); } /* Prepare BD: chain to next BD(s) */ for (i = 0, rdesc = sqi->ring; i < PESQI_BD_COUNT - 1; i++) bd[i].bd_nextp = rdesc[i + 1].bd_dma; bd[PESQI_BD_COUNT - 1].bd_nextp = 0; return 0; } static void ring_desc_ring_free(struct pic32_sqi *sqi) { dma_free_coherent(&sqi->master->dev, sizeof(struct buf_desc) * PESQI_BD_COUNT, sqi->bd, sqi->bd_dma); kfree(sqi->ring); } static void pic32_sqi_hw_init(struct pic32_sqi *sqi) { unsigned long flags; u32 val; /* Soft-reset of PESQI controller triggers interrupt. * We are not yet ready to handle them so disable CPU * interrupt for the time being. */ local_irq_save(flags); /* assert soft-reset */ writel(PESQI_SOFT_RESET, sqi->regs + PESQI_CONF_REG); /* wait until clear */ readl_poll_timeout_atomic(sqi->regs + PESQI_CONF_REG, val, !(val & PESQI_SOFT_RESET), 1, 5000); /* disable all interrupts */ pic32_sqi_disable_int(sqi); /* Now it is safe to enable back CPU interrupt */ local_irq_restore(flags); /* tx and rx fifo interrupt threshold */ val = readl(sqi->regs + PESQI_CMD_THRES_REG); val &= ~(PESQI_TXTHR_MASK << PESQI_TXTHR_SHIFT); val &= ~(PESQI_RXTHR_MASK << PESQI_RXTHR_SHIFT); val |= (1U << PESQI_TXTHR_SHIFT) | (1U << PESQI_RXTHR_SHIFT); writel(val, sqi->regs + PESQI_CMD_THRES_REG); val = readl(sqi->regs + PESQI_INT_THRES_REG); val &= ~(PESQI_TXTHR_MASK << PESQI_TXTHR_SHIFT); val &= ~(PESQI_RXTHR_MASK << PESQI_RXTHR_SHIFT); val |= (1U << PESQI_TXTHR_SHIFT) | (1U << PESQI_RXTHR_SHIFT); writel(val, sqi->regs + PESQI_INT_THRES_REG); /* default configuration */ val = readl(sqi->regs + PESQI_CONF_REG); /* set mode: DMA */ val &= ~PESQI_MODE; val |= PESQI_MODE_DMA << PESQI_MODE_SHIFT; writel(val, sqi->regs + PESQI_CONF_REG); /* DATAEN - SQIID0-ID3 */ val |= PESQI_QUAD_LANE << PESQI_LANES_SHIFT; /* burst/INCR4 enable */ val |= PESQI_BURST_EN; /* CSEN - all CS */ val |= 3U << PESQI_CSEN_SHIFT; writel(val, sqi->regs + PESQI_CONF_REG); /* write poll count */ writel(0, sqi->regs + PESQI_BD_POLL_CTRL_REG); sqi->cur_speed = 0; sqi->cur_mode = -1; } static int pic32_sqi_probe(struct platform_device *pdev) { struct spi_master *master; struct pic32_sqi *sqi; struct resource *reg; int ret; master = spi_alloc_master(&pdev->dev, sizeof(*sqi)); if (!master) return -ENOMEM; sqi = spi_master_get_devdata(master); sqi->master = master; reg = platform_get_resource(pdev, IORESOURCE_MEM, 0); sqi->regs = devm_ioremap_resource(&pdev->dev, reg); if (IS_ERR(sqi->regs)) { ret = PTR_ERR(sqi->regs); goto err_free_master; } /* irq */ sqi->irq = platform_get_irq(pdev, 0); if (sqi->irq < 0) { dev_err(&pdev->dev, "no irq found\n"); ret = sqi->irq; goto err_free_master; } /* clocks */ sqi->sys_clk = devm_clk_get(&pdev->dev, "reg_ck"); if (IS_ERR(sqi->sys_clk)) { ret = PTR_ERR(sqi->sys_clk); dev_err(&pdev->dev, "no sys_clk ?\n"); goto err_free_master; } sqi->base_clk = devm_clk_get(&pdev->dev, "spi_ck"); if (IS_ERR(sqi->base_clk)) { ret = PTR_ERR(sqi->base_clk); dev_err(&pdev->dev, "no base clk ?\n"); goto err_free_master; } ret = clk_prepare_enable(sqi->sys_clk); if (ret) { dev_err(&pdev->dev, "sys clk enable failed\n"); goto err_free_master; } ret = clk_prepare_enable(sqi->base_clk); if (ret) { dev_err(&pdev->dev, "base clk enable failed\n"); clk_disable_unprepare(sqi->sys_clk); goto err_free_master; } init_completion(&sqi->xfer_done); /* initialize hardware */ pic32_sqi_hw_init(sqi); /* allocate buffers & descriptors */ ret = ring_desc_ring_alloc(sqi); if (ret) { dev_err(&pdev->dev, "ring alloc failed\n"); goto err_disable_clk; } /* install irq handlers */ ret = request_irq(sqi->irq, pic32_sqi_isr, 0, dev_name(&pdev->dev), sqi); if (ret < 0) { dev_err(&pdev->dev, "request_irq(%d), failed\n", sqi->irq); goto err_free_ring; } /* register master */ master->num_chipselect = 2; master->max_speed_hz = clk_get_rate(sqi->base_clk); master->dma_alignment = 32; master->max_dma_len = PESQI_BD_BUF_LEN_MAX; master->dev.of_node = of_node_get(pdev->dev.of_node); master->mode_bits = SPI_MODE_3 | SPI_MODE_0 | SPI_TX_DUAL | SPI_RX_DUAL | SPI_TX_QUAD | SPI_RX_QUAD; master->flags = SPI_MASTER_HALF_DUPLEX; master->can_dma = pic32_sqi_can_dma; master->bits_per_word_mask = SPI_BPW_RANGE_MASK(8, 32); master->transfer_one_message = pic32_sqi_one_message; master->prepare_transfer_hardware = pic32_sqi_prepare_hardware; master->unprepare_transfer_hardware = pic32_sqi_unprepare_hardware; ret = devm_spi_register_master(&pdev->dev, master); if (ret) { dev_err(&master->dev, "failed registering spi master\n"); free_irq(sqi->irq, sqi); goto err_free_ring; } platform_set_drvdata(pdev, sqi); return 0; err_free_ring: ring_desc_ring_free(sqi); err_disable_clk: clk_disable_unprepare(sqi->base_clk); clk_disable_unprepare(sqi->sys_clk); err_free_master: spi_master_put(master); return ret; } static int pic32_sqi_remove(struct platform_device *pdev) { struct pic32_sqi *sqi = platform_get_drvdata(pdev); /* release resources */ free_irq(sqi->irq, sqi); ring_desc_ring_free(sqi); /* disable clk */ clk_disable_unprepare(sqi->base_clk); clk_disable_unprepare(sqi->sys_clk); return 0; } static const struct of_device_id pic32_sqi_of_ids[] = { {.compatible = "microchip,pic32mzda-sqi",}, {}, }; MODULE_DEVICE_TABLE(of, pic32_sqi_of_ids); static struct platform_driver pic32_sqi_driver = { .driver = { .name = "sqi-pic32", .of_match_table = of_match_ptr(pic32_sqi_of_ids), }, .probe = pic32_sqi_probe, .remove = pic32_sqi_remove, }; module_platform_driver(pic32_sqi_driver); MODULE_AUTHOR("Purna Chandra Mandal <purna.mandal@microchip.com>"); MODULE_DESCRIPTION("Microchip SPI driver for PIC32 SQI controller."); MODULE_LICENSE("GPL v2");