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Release 4.14 drivers/spi/spi-stm32.c

Directory: drivers/spi
/*
 * STMicroelectronics STM32 SPI Controller driver (master mode only)
 *
 * Copyright (C) 2017, STMicroelectronics - All Rights Reserved
 * Author(s): Amelie Delaunay <amelie.delaunay@st.com> for STMicroelectronics.
 *
 * License terms: GPL V2.0.
 *
 * spi_stm32 driver 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.
 *
 * spi_stm32 driver 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.
 *
 * You should have received a copy of the GNU General Public License along with
 * spi_stm32 driver. If not, see <http://www.gnu.org/licenses/>.
 */
#include <linux/debugfs.h>
#include <linux/clk.h>
#include <linux/delay.h>
#include <linux/dmaengine.h>
#include <linux/gpio.h>
#include <linux/interrupt.h>
#include <linux/iopoll.h>
#include <linux/module.h>
#include <linux/of_platform.h>
#include <linux/pm_runtime.h>
#include <linux/reset.h>
#include <linux/spi/spi.h>


#define DRIVER_NAME "spi_stm32"

/* STM32 SPI registers */

#define STM32_SPI_CR1		0x00

#define STM32_SPI_CR2		0x04

#define STM32_SPI_CFG1		0x08

#define STM32_SPI_CFG2		0x0C

#define STM32_SPI_IER		0x10

#define STM32_SPI_SR		0x14

#define STM32_SPI_IFCR		0x18

#define STM32_SPI_TXDR		0x20

#define STM32_SPI_RXDR		0x30

#define STM32_SPI_I2SCFGR	0x50

/* STM32_SPI_CR1 bit fields */

#define SPI_CR1_SPE		BIT(0)

#define SPI_CR1_MASRX		BIT(8)

#define SPI_CR1_CSTART		BIT(9)

#define SPI_CR1_CSUSP		BIT(10)

#define SPI_CR1_HDDIR		BIT(11)

#define SPI_CR1_SSI		BIT(12)

/* STM32_SPI_CR2 bit fields */

#define SPI_CR2_TSIZE_SHIFT	0

#define SPI_CR2_TSIZE		GENMASK(15, 0)

/* STM32_SPI_CFG1 bit fields */

#define SPI_CFG1_DSIZE_SHIFT	0

#define SPI_CFG1_DSIZE		GENMASK(4, 0)

#define SPI_CFG1_FTHLV_SHIFT	5

#define SPI_CFG1_FTHLV		GENMASK(8, 5)

#define SPI_CFG1_RXDMAEN	BIT(14)

#define SPI_CFG1_TXDMAEN	BIT(15)

#define SPI_CFG1_MBR_SHIFT	28

#define SPI_CFG1_MBR		GENMASK(30, 28)

#define SPI_CFG1_MBR_MIN	0

#define SPI_CFG1_MBR_MAX	(GENMASK(30, 28) >> 28)

/* STM32_SPI_CFG2 bit fields */

#define SPI_CFG2_MIDI_SHIFT	4

#define SPI_CFG2_MIDI		GENMASK(7, 4)

#define SPI_CFG2_COMM_SHIFT	17

#define SPI_CFG2_COMM		GENMASK(18, 17)

#define SPI_CFG2_SP_SHIFT	19

#define SPI_CFG2_SP		GENMASK(21, 19)

#define SPI_CFG2_MASTER		BIT(22)

#define SPI_CFG2_LSBFRST	BIT(23)

#define SPI_CFG2_CPHA		BIT(24)

#define SPI_CFG2_CPOL		BIT(25)

#define SPI_CFG2_SSM		BIT(26)

#define SPI_CFG2_AFCNTR		BIT(31)

/* STM32_SPI_IER bit fields */

#define SPI_IER_RXPIE		BIT(0)

#define SPI_IER_TXPIE		BIT(1)

#define SPI_IER_DXPIE		BIT(2)

#define SPI_IER_EOTIE		BIT(3)

#define SPI_IER_TXTFIE		BIT(4)

#define SPI_IER_OVRIE		BIT(6)

#define SPI_IER_MODFIE		BIT(9)

#define SPI_IER_ALL		GENMASK(10, 0)

/* STM32_SPI_SR bit fields */

#define SPI_SR_RXP		BIT(0)

#define SPI_SR_TXP		BIT(1)

#define SPI_SR_EOT		BIT(3)

#define SPI_SR_OVR		BIT(6)

#define SPI_SR_MODF		BIT(9)

#define SPI_SR_SUSP		BIT(11)

#define SPI_SR_RXPLVL_SHIFT	13

#define SPI_SR_RXPLVL		GENMASK(14, 13)

#define SPI_SR_RXWNE		BIT(15)

/* STM32_SPI_IFCR bit fields */

#define SPI_IFCR_ALL		GENMASK(11, 3)

/* STM32_SPI_I2SCFGR bit fields */

#define SPI_I2SCFGR_I2SMOD	BIT(0)

/* SPI Master Baud Rate min/max divisor */

#define SPI_MBR_DIV_MIN		(2 << SPI_CFG1_MBR_MIN)

#define SPI_MBR_DIV_MAX		(2 << SPI_CFG1_MBR_MAX)

/* SPI Communication mode */

#define SPI_FULL_DUPLEX		0

#define SPI_SIMPLEX_TX		1

#define SPI_SIMPLEX_RX		2

#define SPI_HALF_DUPLEX		3


#define SPI_1HZ_NS		1000000000

/**
 * struct stm32_spi - private data of the SPI controller
 * @dev: driver model representation of the controller
 * @master: controller master interface
 * @base: virtual memory area
 * @clk: hw kernel clock feeding the SPI clock generator
 * @clk_rate: rate of the hw kernel clock feeding the SPI clock generator
 * @rst: SPI controller reset line
 * @lock: prevent I/O concurrent access
 * @irq: SPI controller interrupt line
 * @fifo_size: size of the embedded fifo in bytes
 * @cur_midi: master inter-data idleness in ns
 * @cur_speed: speed configured in Hz
 * @cur_bpw: number of bits in a single SPI data frame
 * @cur_fthlv: fifo threshold level (data frames in a single data packet)
 * @cur_comm: SPI communication mode
 * @cur_xferlen: current transfer length in bytes
 * @cur_usedma: boolean to know if dma is used in current transfer
 * @tx_buf: data to be written, or NULL
 * @rx_buf: data to be read, or NULL
 * @tx_len: number of data to be written in bytes
 * @rx_len: number of data to be read in bytes
 * @dma_tx: dma channel for TX transfer
 * @dma_rx: dma channel for RX transfer
 * @phys_addr: SPI registers physical base address
 */

struct stm32_spi {
	
struct device *dev;
	
struct spi_master *master;
	
void __iomem *base;
	
struct clk *clk;
	
u32 clk_rate;
	
struct reset_control *rst;
	
spinlock_t lock; /* prevent I/O concurrent access */
	
int irq;
	
unsigned int fifo_size;

	
unsigned int cur_midi;
	
unsigned int cur_speed;
	
unsigned int cur_bpw;
	
unsigned int cur_fthlv;
	
unsigned int cur_comm;
	
unsigned int cur_xferlen;
	
bool cur_usedma;

	
const void *tx_buf;
	
void *rx_buf;
	
int tx_len;
	
int rx_len;
	
struct dma_chan *dma_tx;
	
struct dma_chan *dma_rx;
	
dma_addr_t phys_addr;
};


static inline void stm32_spi_set_bits(struct stm32_spi *spi, u32 offset, u32 bits) { writel_relaxed(readl_relaxed(spi->base + offset) | bits, spi->base + offset); }

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static inline void stm32_spi_clr_bits(struct stm32_spi *spi, u32 offset, u32 bits) { writel_relaxed(readl_relaxed(spi->base + offset) & ~bits, spi->base + offset); }

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/** * stm32_spi_get_fifo_size - Return fifo size * @spi: pointer to the spi controller data structure */
static int stm32_spi_get_fifo_size(struct stm32_spi *spi) { unsigned long flags; u32 count = 0; spin_lock_irqsave(&spi->lock, flags); stm32_spi_set_bits(spi, STM32_SPI_CR1, SPI_CR1_SPE); while (readl_relaxed(spi->base + STM32_SPI_SR) & SPI_SR_TXP) writeb_relaxed(++count, spi->base + STM32_SPI_TXDR); stm32_spi_clr_bits(spi, STM32_SPI_CR1, SPI_CR1_SPE); spin_unlock_irqrestore(&spi->lock, flags); dev_dbg(spi->dev, "%d x 8-bit fifo size\n", count); return count; }

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/** * stm32_spi_get_bpw_mask - Return bits per word mask * @spi: pointer to the spi controller data structure */
static int stm32_spi_get_bpw_mask(struct stm32_spi *spi) { unsigned long flags; u32 cfg1, max_bpw; spin_lock_irqsave(&spi->lock, flags); /* * The most significant bit at DSIZE bit field is reserved when the * maximum data size of periperal instances is limited to 16-bit */ stm32_spi_set_bits(spi, STM32_SPI_CFG1, SPI_CFG1_DSIZE); cfg1 = readl_relaxed(spi->base + STM32_SPI_CFG1); max_bpw = (cfg1 & SPI_CFG1_DSIZE) >> SPI_CFG1_DSIZE_SHIFT; max_bpw += 1; spin_unlock_irqrestore(&spi->lock, flags); dev_dbg(spi->dev, "%d-bit maximum data frame\n", max_bpw); return SPI_BPW_RANGE_MASK(4, max_bpw); }

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/** * stm32_spi_prepare_mbr - Determine SPI_CFG1.MBR value * @spi: pointer to the spi controller data structure * @speed_hz: requested speed * * Return SPI_CFG1.MBR value in case of success or -EINVAL */
static int stm32_spi_prepare_mbr(struct stm32_spi *spi, u32 speed_hz) { u32 div, mbrdiv; div = DIV_ROUND_UP(spi->clk_rate, speed_hz); /* * SPI framework set xfer->speed_hz to master->max_speed_hz if * xfer->speed_hz is greater than master->max_speed_hz, and it returns * an error when xfer->speed_hz is lower than master->min_speed_hz, so * no need to check it there. * However, we need to ensure the following calculations. */ if (div < SPI_MBR_DIV_MIN || div > SPI_MBR_DIV_MAX) return -EINVAL; /* Determine the first power of 2 greater than or equal to div */ if (div & (div - 1)) mbrdiv = fls(div); else mbrdiv = fls(div) - 1; spi->cur_speed = spi->clk_rate / (1 << mbrdiv); return mbrdiv - 1; }

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/** * stm32_spi_prepare_fthlv - Determine FIFO threshold level * @spi: pointer to the spi controller data structure */
static u32 stm32_spi_prepare_fthlv(struct stm32_spi *spi) { u32 fthlv, half_fifo; /* data packet should not exceed 1/2 of fifo space */ half_fifo = (spi->fifo_size / 2); if (spi->cur_bpw <= 8) fthlv = half_fifo; else if (spi->cur_bpw <= 16) fthlv = half_fifo / 2; else fthlv = half_fifo / 4; /* align packet size with data registers access */ if (spi->cur_bpw > 8) fthlv -= (fthlv % 2); /* multiple of 2 */ else fthlv -= (fthlv % 4); /* multiple of 4 */ return fthlv; }

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/** * stm32_spi_write_txfifo - Write bytes in Transmit Data Register * @spi: pointer to the spi controller data structure * * Read from tx_buf depends on remaining bytes to avoid to read beyond * tx_buf end. */
static void stm32_spi_write_txfifo(struct stm32_spi *spi) { while ((spi->tx_len > 0) && (readl_relaxed(spi->base + STM32_SPI_SR) & SPI_SR_TXP)) { u32 offs = spi->cur_xferlen - spi->tx_len; if (spi->tx_len >= sizeof(u32)) { const u32 *tx_buf32 = (const u32 *)(spi->tx_buf + offs); writel_relaxed(*tx_buf32, spi->base + STM32_SPI_TXDR); spi->tx_len -= sizeof(u32); } else if (spi->tx_len >= sizeof(u16)) { const u16 *tx_buf16 = (const u16 *)(spi->tx_buf + offs); writew_relaxed(*tx_buf16, spi->base + STM32_SPI_TXDR); spi->tx_len -= sizeof(u16); } else { const u8 *tx_buf8 = (const u8 *)(spi->tx_buf + offs); writeb_relaxed(*tx_buf8, spi->base + STM32_SPI_TXDR); spi->tx_len -= sizeof(u8); } } dev_dbg(spi->dev, "%s: %d bytes left\n", __func__, spi->tx_len); }

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/** * stm32_spi_read_rxfifo - Read bytes in Receive Data Register * @spi: pointer to the spi controller data structure * * Write in rx_buf depends on remaining bytes to avoid to write beyond * rx_buf end. */
static void stm32_spi_read_rxfifo(struct stm32_spi *spi, bool flush) { u32 sr = readl_relaxed(spi->base + STM32_SPI_SR); u32 rxplvl = (sr & SPI_SR_RXPLVL) >> SPI_SR_RXPLVL_SHIFT; while ((spi->rx_len > 0) && ((sr & SPI_SR_RXP) || (flush && ((sr & SPI_SR_RXWNE) || (rxplvl > 0))))) { u32 offs = spi->cur_xferlen - spi->rx_len; if ((spi->rx_len >= sizeof(u32)) || (flush && (sr & SPI_SR_RXWNE))) { u32 *rx_buf32 = (u32 *)(spi->rx_buf + offs); *rx_buf32 = readl_relaxed(spi->base + STM32_SPI_RXDR); spi->rx_len -= sizeof(u32); } else if ((spi->rx_len >= sizeof(u16)) || (flush && (rxplvl >= 2 || spi->cur_bpw > 8))) { u16 *rx_buf16 = (u16 *)(spi->rx_buf + offs); *rx_buf16 = readw_relaxed(spi->base + STM32_SPI_RXDR); spi->rx_len -= sizeof(u16); } else { u8 *rx_buf8 = (u8 *)(spi->rx_buf + offs); *rx_buf8 = readb_relaxed(spi->base + STM32_SPI_RXDR); spi->rx_len -= sizeof(u8); } sr = readl_relaxed(spi->base + STM32_SPI_SR); rxplvl = (sr & SPI_SR_RXPLVL) >> SPI_SR_RXPLVL_SHIFT; } dev_dbg(spi->dev, "%s%s: %d bytes left\n", __func__, flush ? "(flush)" : "", spi->rx_len); }

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/** * stm32_spi_enable - Enable SPI controller * @spi: pointer to the spi controller data structure * * SPI data transfer is enabled but spi_ker_ck is idle. * SPI_CFG1 and SPI_CFG2 are now write protected. */
static void stm32_spi_enable(struct stm32_spi *spi) { dev_dbg(spi->dev, "enable controller\n"); stm32_spi_set_bits(spi, STM32_SPI_CR1, SPI_CR1_SPE); }

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/** * stm32_spi_disable - Disable SPI controller * @spi: pointer to the spi controller data structure * * RX-Fifo is flushed when SPI controller is disabled. To prevent any data * loss, use stm32_spi_read_rxfifo(flush) to read the remaining bytes in * RX-Fifo. */
static void stm32_spi_disable(struct stm32_spi *spi) { unsigned long flags; u32 cr1, sr; dev_dbg(spi->dev, "disable controller\n"); spin_lock_irqsave(&spi->lock, flags); cr1 = readl_relaxed(spi->base + STM32_SPI_CR1); if (!(cr1 & SPI_CR1_SPE)) { spin_unlock_irqrestore(&spi->lock, flags); return; } /* Wait on EOT or suspend the flow */ if (readl_relaxed_poll_timeout_atomic(spi->base + STM32_SPI_SR, sr, !(sr & SPI_SR_EOT), 10, 100000) < 0) { if (cr1 & SPI_CR1_CSTART) { writel_relaxed(cr1 | SPI_CR1_CSUSP, spi->base + STM32_SPI_CR1); if (readl_relaxed_poll_timeout_atomic( spi->base + STM32_SPI_SR, sr, !(sr & SPI_SR_SUSP), 10, 100000) < 0) dev_warn(spi->dev, "Suspend request timeout\n"); } } if (!spi->cur_usedma && spi->rx_buf && (spi->rx_len > 0)) stm32_spi_read_rxfifo(spi, true); if (spi->cur_usedma && spi->tx_buf) dmaengine_terminate_all(spi->dma_tx); if (spi->cur_usedma && spi->rx_buf) dmaengine_terminate_all(spi->dma_rx); stm32_spi_clr_bits(spi, STM32_SPI_CR1, SPI_CR1_SPE); stm32_spi_clr_bits(spi, STM32_SPI_CFG1, SPI_CFG1_TXDMAEN | SPI_CFG1_RXDMAEN); /* Disable interrupts and clear status flags */ writel_relaxed(0, spi->base + STM32_SPI_IER); writel_relaxed(SPI_IFCR_ALL, spi->base + STM32_SPI_IFCR); spin_unlock_irqrestore(&spi->lock, flags); }

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/** * stm32_spi_can_dma - Determine if the transfer is eligible for DMA use * * If the current transfer size is greater than fifo size, use DMA. */
static bool stm32_spi_can_dma(struct spi_master *master, struct spi_device *spi_dev, struct spi_transfer *transfer) { struct stm32_spi *spi = spi_master_get_devdata(master); dev_dbg(spi->dev, "%s: %s\n", __func__, (transfer->len > spi->fifo_size) ? "true" : "false"); return (transfer->len > spi->fifo_size); }

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/** * stm32_spi_irq - Interrupt handler for SPI controller events * @irq: interrupt line * @dev_id: SPI controller master interface */
static irqreturn_t stm32_spi_irq(int irq, void *dev_id) { struct spi_master *master = dev_id; struct stm32_spi *spi = spi_master_get_devdata(master); u32 sr, ier, mask; unsigned long flags; bool end = false; spin_lock_irqsave(&spi->lock, flags); sr = readl_relaxed(spi->base + STM32_SPI_SR); ier = readl_relaxed(spi->base + STM32_SPI_IER); mask = ier; /* EOTIE is triggered on EOT, SUSP and TXC events. */ mask |= SPI_SR_SUSP; /* * When TXTF is set, DXPIE and TXPIE are cleared. So in case of * Full-Duplex, need to poll RXP event to know if there are remaining * data, before disabling SPI. */ if (spi->rx_buf && !spi->cur_usedma) mask |= SPI_SR_RXP; if (!(sr & mask)) { dev_dbg(spi->dev, "spurious IT (sr=0x%08x, ier=0x%08x)\n", sr, ier); spin_unlock_irqrestore(&spi->lock, flags); return IRQ_NONE; } if (sr & SPI_SR_SUSP) { dev_warn(spi->dev, "Communication suspended\n"); if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0))) stm32_spi_read_rxfifo(spi, false); /* * If communication is suspended while using DMA, it means * that something went wrong, so stop the current transfer */ if (spi->cur_usedma) end = true; } if (sr & SPI_SR_MODF) { dev_warn(spi->dev, "Mode fault: transfer aborted\n"); end = true; } if (sr & SPI_SR_OVR) { dev_warn(spi->dev, "Overrun: received value discarded\n"); if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0))) stm32_spi_read_rxfifo(spi, false); /* * If overrun is detected while using DMA, it means that * something went wrong, so stop the current transfer */ if (spi->cur_usedma) end = true; } if (sr & SPI_SR_EOT) { if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0))) stm32_spi_read_rxfifo(spi, true); end = true; } if (sr & SPI_SR_TXP) if (!spi->cur_usedma && (spi->tx_buf && (spi->tx_len > 0))) stm32_spi_write_txfifo(spi); if (sr & SPI_SR_RXP) if (!spi->cur_usedma && (spi->rx_buf && (spi->rx_len > 0))) stm32_spi_read_rxfifo(spi, false); writel_relaxed(mask, spi->base + STM32_SPI_IFCR); spin_unlock_irqrestore(&spi->lock, flags); if (end) { spi_finalize_current_transfer(master); stm32_spi_disable(spi); } return IRQ_HANDLED; }

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/** * stm32_spi_setup - setup device chip select */
static int stm32_spi_setup(struct spi_device *spi_dev) { int ret = 0; if (!gpio_is_valid(spi_dev->cs_gpio)) { dev_err(&spi_dev->dev, "%d is not a valid gpio\n", spi_dev->cs_gpio); return -EINVAL; } dev_dbg(&spi_dev->dev, "%s: set gpio%d output %s\n", __func__, spi_dev->cs_gpio, (spi_dev->mode & SPI_CS_HIGH) ? "low" : "high"); ret = gpio_direction_output(spi_dev->cs_gpio, !(spi_dev->mode & SPI_CS_HIGH)); return ret; }

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/** * stm32_spi_prepare_msg - set up the controller to transfer a single message */
static int stm32_spi_prepare_msg(struct spi_master *master, struct spi_message *msg) { struct stm32_spi *spi = spi_master_get_devdata(master); struct spi_device *spi_dev = msg->spi; struct device_node *np = spi_dev->dev.of_node; unsigned long flags; u32 cfg2_clrb = 0, cfg2_setb = 0; /* SPI slave device may need time between data frames */ spi->cur_midi = 0; if (np && !of_property_read_u32(np, "st,spi-midi-ns", &spi->cur_midi)) dev_dbg(spi->dev, "%dns inter-data idleness\n", spi->cur_midi); if (spi_dev->mode & SPI_CPOL) cfg2_setb |= SPI_CFG2_CPOL; else cfg2_clrb |= SPI_CFG2_CPOL; if (spi_dev->mode & SPI_CPHA) cfg2_setb |= SPI_CFG2_CPHA; else cfg2_clrb |= SPI_CFG2_CPHA; if (spi_dev->mode & SPI_LSB_FIRST) cfg2_setb |= SPI_CFG2_LSBFRST; else cfg2_clrb |= SPI_CFG2_LSBFRST; dev_dbg(spi->dev, "cpol=%d cpha=%d lsb_first=%d cs_high=%d\n", spi_dev->mode & SPI_CPOL, spi_dev->mode & SPI_CPHA, spi_dev->mode & SPI_LSB_FIRST, spi_dev->mode & SPI_CS_HIGH); spin_lock_irqsave(&spi->lock, flags); if (cfg2_clrb || cfg2_setb) writel_relaxed( (readl_relaxed(spi->base + STM32_SPI_CFG2) & ~cfg2_clrb) | cfg2_setb, spi->base + STM32_SPI_CFG2); spin_unlock_irqrestore(&spi->lock, flags); return 0; }

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/** * stm32_spi_dma_cb - dma callback * * DMA callback is called when the transfer is complete or when an error * occurs. If the transfer is complete, EOT flag is raised. */
static void stm32_spi_dma_cb(void *data) { struct stm32_spi *spi = data; unsigned long flags; u32 sr; spin_lock_irqsave(&spi->lock, flags); sr = readl_relaxed(spi->base + STM32_SPI_SR); spin_unlock_irqrestore(&spi->lock, flags); if (!(sr & SPI_SR_EOT)) dev_warn(spi->dev, "DMA error (sr=0x%08x)\n", sr); /* Now wait for EOT, or SUSP or OVR in case of error */ }

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/** * stm32_spi_dma_config - configure dma slave channel depending on current * transfer bits_per_word. */
static void stm32_spi_dma_config(struct stm32_spi *spi, struct dma_slave_config *dma_conf, enum dma_transfer_direction dir) { enum dma_slave_buswidth buswidth; u32 maxburst; if (spi->cur_bpw <= 8) buswidth = DMA_SLAVE_BUSWIDTH_1_BYTE; else if (spi->cur_bpw <= 16) buswidth = DMA_SLAVE_BUSWIDTH_2_BYTES; else buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES; /* Valid for DMA Half or Full Fifo threshold */ if (spi->cur_fthlv == 2) maxburst = 1; else maxburst = spi->cur_fthlv; memset(dma_conf, 0, sizeof(struct dma_slave_config)); dma_conf->direction = dir; if (dma_conf->direction == DMA_DEV_TO_MEM) { /* RX */ dma_conf->src_addr = spi->phys_addr + STM32_SPI_RXDR; dma_conf->src_addr_width = buswidth; dma_conf->src_maxburst = maxburst; dev_dbg(spi->dev, "Rx DMA config buswidth=%d, maxburst=%d\n", buswidth, maxburst); } else if (dma_conf->direction == DMA_MEM_TO_DEV) { /* TX */ dma_conf->dst_addr = spi->phys_addr + STM32_SPI_TXDR; dma_conf->dst_addr_width = buswidth; dma_conf->dst_maxburst = maxburst; dev_dbg(spi->dev, "Tx DMA config buswidth=%d, maxburst=%d\n", buswidth, maxburst); } }

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/** * stm32_spi_transfer_one_irq - transfer a single spi_transfer using * interrupts * * It must returns 0 if the transfer is finished or 1 if the transfer is still * in progress. */
static int stm32_spi_transfer_one_irq(struct stm32_spi *spi) { unsigned long flags; u32 ier = 0; /* Enable the interrupts relative to the current communication mode */ if (spi->tx_buf && spi->rx_buf) /* Full Duplex */ ier |= SPI_IER_DXPIE; else if (spi->tx_buf) /* Half-Duplex TX dir or Simplex TX */ ier |= SPI_IER_TXPIE; else if (spi->rx_buf) /* Half-Duplex RX dir or Simplex RX */ ier |= SPI_IER_RXPIE; /* Enable the interrupts relative to the end of transfer */ ier |= SPI_IER_EOTIE | SPI_IER_TXTFIE | SPI_IER_OVRIE | SPI_IER_MODFIE; spin_lock_irqsave(&spi->lock, flags); stm32_spi_enable(spi); /* Be sure to have data in fifo before starting data transfer */ if (spi->tx_buf) stm32_spi_write_txfifo(spi); stm32_spi_set_bits(spi, STM32_SPI_CR1, SPI_CR1_CSTART); writel_relaxed(ier, spi->base + STM32_SPI_IER); spin_unlock_irqrestore(&spi->lock, flags); return 1; }

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/** * stm32_spi_transfer_one_dma - transfer a single spi_transfer using DMA * * It must returns 0 if the transfer is finished or 1 if the transfer is still * in progress. */
static int stm32_spi_transfer_one_dma(struct stm32_spi *spi, struct spi_transfer *xfer) { struct dma_slave_config tx_dma_conf, rx_dma_conf; struct dma_async_tx_descriptor *tx_dma_desc, *rx_dma_desc; unsigned long flags; u32 ier = 0; spin_lock_irqsave(&spi->lock, flags); rx_dma_desc = NULL; if (spi->rx_buf) { stm32_spi_dma_config(spi, &rx_dma_conf, DMA_DEV_TO_MEM); dmaengine_slave_config(spi->dma_rx, &rx_dma_conf); /* Enable Rx DMA request */ stm32_spi_set_bits(spi, STM32_SPI_CFG1, SPI_CFG1_RXDMAEN); rx_dma_desc = dmaengine_prep_slave_sg( spi->dma_rx, xfer->rx_sg.sgl, xfer->rx_sg.nents, rx_dma_conf.direction, DMA_PREP_INTERRUPT); } tx_dma_desc = NULL; if (spi->tx_buf) { stm32_spi_dma_config(spi, &tx_dma_conf, DMA_MEM_TO_DEV); dmaengine_slave_config(spi->dma_tx, &tx_dma_conf); tx_dma_desc = dmaengine_prep_slave_sg( spi->dma_tx, xfer->tx_sg.sgl, xfer->tx_sg.nents, tx_dma_conf.direction, DMA_PREP_INTERRUPT); } if ((spi->tx_buf && !tx_dma_desc) || (spi->rx_buf && !rx_dma_desc)) goto dma_desc_error; if (rx_dma_desc) { rx_dma_desc->callback = stm32_spi_dma_cb; rx_dma_desc->callback_param = spi; if (dma_submit_error(dmaengine_submit(rx_dma_desc))) { dev_err(spi->dev, "Rx DMA submit failed\n"); goto dma_desc_error; } /* Enable Rx DMA channel */ dma_async_issue_pending(spi->dma_rx); } if (tx_dma_desc) { if (spi->cur_comm == SPI_SIMPLEX_TX) { tx_dma_desc->callback = stm32_spi_dma_cb; tx_dma_desc->callback_param = spi; } if (dma_submit_error(dmaengine_submit(tx_dma_desc))) { dev_err(spi->dev, "Tx DMA submit failed\n"); goto dma_submit_error; } /* Enable Tx DMA channel */ dma_async_issue_pending(spi->dma_tx); /* Enable Tx DMA request */ stm32_spi_set_bits(spi, STM32_SPI_CFG1, SPI_CFG1_TXDMAEN); } /* Enable the interrupts relative to the end of transfer */ ier |= SPI_IER_EOTIE | SPI_IER_TXTFIE | SPI_IER_OVRIE | SPI_IER_MODFIE; writel_relaxed(ier, spi->base + STM32_SPI_IER); stm32_spi_enable(spi); stm32_spi_set_bits(spi, STM32_SPI_CR1, SPI_CR1_CSTART); spin_unlock_irqrestore(&spi->lock, flags); return 1; dma_submit_error: if (spi->rx_buf) dmaengine_terminate_all(spi->dma_rx); dma_desc_error: stm32_spi_clr_bits(spi, STM32_SPI_CFG1, SPI_CFG1_RXDMAEN); spin_unlock_irqrestore(&spi->lock, flags); dev_info(spi->dev, "DMA issue: fall back to irq transfer\n"); return stm32_spi_transfer_one_irq(spi); }

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/** * stm32_spi_transfer_one_setup - common setup to transfer a single * spi_transfer either using DMA or * interrupts. */
static int stm32_spi_transfer_one_setup(struct stm32_spi *spi, struct spi_device *spi_dev, struct spi_transfer *transfer) { unsigned long flags; u32 cfg1_clrb = 0, cfg1_setb = 0, cfg2_clrb = 0, cfg2_setb = 0; u32 mode, nb_words; int ret = 0; spin_lock_irqsave(&spi->lock, flags); if (spi->cur_bpw != transfer->bits_per_word) { u32 bpw, fthlv; spi->cur_bpw = transfer->bits_per_word; bpw = spi->cur_bpw - 1; cfg1_clrb |= SPI_CFG1_DSIZE; cfg1_setb |= (bpw << SPI_CFG1_DSIZE_SHIFT) & SPI_CFG1_DSIZE; spi->cur_fthlv = stm32_spi_prepare_fthlv(spi); fthlv = spi->cur_fthlv - 1; cfg1_clrb |= SPI_CFG1_FTHLV; cfg1_setb |= (fthlv << SPI_CFG1_FTHLV_SHIFT) & SPI_CFG1_FTHLV; } if (spi->cur_speed != transfer->speed_hz) { int mbr; /* Update spi->cur_speed with real clock speed */ mbr = stm32_spi_prepare_mbr(spi, transfer->speed_hz); if (mbr < 0) { ret = mbr; goto out; } transfer->speed_hz = spi->cur_speed; cfg1_clrb |= SPI_CFG1_MBR; cfg1_setb |= ((u32)mbr << SPI_CFG1_MBR_SHIFT) & SPI_CFG1_MBR; } if (cfg1_clrb || cfg1_setb) writel_relaxed((readl_relaxed(spi->base + STM32_SPI_CFG1) & ~cfg1_clrb) | cfg1_setb, spi->base + STM32_SPI_CFG1); mode = SPI_FULL_DUPLEX; if (spi_dev->mode & SPI_3WIRE) { /* MISO/MOSI signals shared */ /* * SPI_3WIRE and xfer->tx_buf != NULL and xfer->rx_buf != NULL * is forbidden und unvalidated by SPI subsystem so depending * on the valid buffer, we can determine the direction of the * transfer. */ mode = SPI_HALF_DUPLEX; if (!transfer->tx_buf) stm32_spi_clr_bits(spi, STM32_SPI_CR1, SPI_CR1_HDDIR); else if (!transfer->rx_buf) stm32_spi_set_bits(spi, STM32_SPI_CR1, SPI_CR1_HDDIR); } else { if (!transfer->tx_buf) mode = SPI_SIMPLEX_RX; else if (!transfer->rx_buf) mode = SPI_SIMPLEX_TX; } if (spi->cur_comm != mode) { spi->cur_comm = mode; cfg2_clrb |= SPI_CFG2_COMM; cfg2_setb |= (mode << SPI_CFG2_COMM_SHIFT) & SPI_CFG2_COMM; } cfg2_clrb |= SPI_CFG2_MIDI; if ((transfer->len > 1) && (spi->cur_midi > 0)) { u32 sck_period_ns = DIV_ROUND_UP(SPI_1HZ_NS, spi->cur_speed); u32 midi = min((u32)DIV_ROUND_UP(spi->cur_midi, sck_period_ns), (u32)SPI_CFG2_MIDI >> SPI_CFG2_MIDI_SHIFT); dev_dbg(spi->dev, "period=%dns, midi=%d(=%dns)\n", sck_period_ns, midi, midi * sck_period_ns); cfg2_setb |= (midi << SPI_CFG2_MIDI_SHIFT) & SPI_CFG2_MIDI; } if (cfg2_clrb || cfg2_setb) writel_relaxed((readl_relaxed(spi->base + STM32_SPI_CFG2) & ~cfg2_clrb) | cfg2_setb, spi->base + STM32_SPI_CFG2); if (spi->cur_bpw <= 8) nb_words = transfer->len; else if (spi->cur_bpw <= 16) nb_words = DIV_ROUND_UP(transfer->len * 8, 16); else nb_words = DIV_ROUND_UP(transfer->len * 8, 32); nb_words <<= SPI_CR2_TSIZE_SHIFT; if (nb_words <= SPI_CR2_TSIZE) { writel_relaxed(nb_words, spi->base + STM32_SPI_CR2); } else { ret = -EMSGSIZE; goto out; } spi->cur_xferlen = transfer->len; dev_dbg(spi->dev, "transfer communication mode set to %d\n", spi->cur_comm); dev_dbg(spi->dev, "data frame of %d-bit, data packet of %d data frames\n", spi->cur_bpw, spi->cur_fthlv); dev_dbg(spi->dev, "speed set to %dHz\n", spi->cur_speed); dev_dbg(spi->dev, "transfer of %d bytes (%d data frames)\n", spi->cur_xferlen, nb_words); dev_dbg(spi->dev, "dma %s\n", (spi->cur_usedma) ? "enabled" : "disabled"); out: spin_unlock_irqrestore(&spi->lock, flags); return ret; }

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/** * stm32_spi_transfer_one - transfer a single spi_transfer * * It must return 0 if the transfer is finished or 1 if the transfer is still * in progress. */
static int stm32_spi_transfer_one(struct spi_master *master, struct spi_device *spi_dev, struct spi_transfer *transfer) { struct stm32_spi *spi = spi_master_get_devdata(master); int ret; spi->tx_buf = transfer->tx_buf; spi->rx_buf = transfer->rx_buf; spi->tx_len = spi->tx_buf ? transfer->len : 0; spi->rx_len = spi->rx_buf ? transfer->len : 0; spi->cur_usedma = (master->can_dma && stm32_spi_can_dma(master, spi_dev, transfer)); ret = stm32_spi_transfer_one_setup(spi, spi_dev, transfer); if (ret) { dev_err(spi->dev, "SPI transfer setup failed\n"); return ret; } if (spi->cur_usedma) return stm32_spi_transfer_one_dma(spi, transfer); else return stm32_spi_transfer_one_irq(spi); }

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/** * stm32_spi_unprepare_msg - relax the hardware * * Normally, if TSIZE has been configured, we should relax the hardware at the * reception of the EOT interrupt. But in case of error, EOT will not be * raised. So the subsystem unprepare_message call allows us to properly * complete the transfer from an hardware point of view. */
static int stm32_spi_unprepare_msg(struct spi_master *master, struct spi_message *msg) { struct stm32_spi *spi = spi_master_get_devdata(master); stm32_spi_disable(spi); return 0; }

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/** * stm32_spi_config - Configure SPI controller as SPI master */
static int stm32_spi_config(struct stm32_spi *spi) { unsigned long flags; spin_lock_irqsave(&spi->lock, flags); /* Ensure I2SMOD bit is kept cleared */ stm32_spi_clr_bits(spi, STM32_SPI_I2SCFGR, SPI_I2SCFGR_I2SMOD); /* * - SS input value high * - transmitter half duplex direction * - automatic communication suspend when RX-Fifo is full */ stm32_spi_set_bits(spi, STM32_SPI_CR1, SPI_CR1_SSI | SPI_CR1_HDDIR | SPI_CR1_MASRX); /* * - Set the master mode (default Motorola mode) * - Consider 1 master/n slaves configuration and * SS input value is determined by the SSI bit * - keep control of all associated GPIOs */ stm32_spi_set_bits(spi, STM32_SPI_CFG2, SPI_CFG2_MASTER | SPI_CFG2_SSM | SPI_CFG2_AFCNTR); spin_unlock_irqrestore(&spi->lock, flags); return 0; }

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static const struct of_device_id stm32_spi_of_match[] = { { .compatible = "st,stm32h7-spi", }, {}, }; MODULE_DEVICE_TABLE(of, stm32_spi_of_match);
static int stm32_spi_probe(struct platform_device *pdev) { struct spi_master *master; struct stm32_spi *spi; struct resource *res; int i, ret; master = spi_alloc_master(&pdev->dev, sizeof(struct stm32_spi)); if (!master) { dev_err(&pdev->dev, "spi master allocation failed\n"); return -ENOMEM; } platform_set_drvdata(pdev, master); spi = spi_master_get_devdata(master); spi->dev = &pdev->dev; spi->master = master; spin_lock_init(&spi->lock); res = platform_get_resource(pdev, IORESOURCE_MEM, 0); spi->base = devm_ioremap_resource(&pdev->dev, res); if (IS_ERR(spi->base)) { ret = PTR_ERR(spi->base); goto err_master_put; } spi->phys_addr = (dma_addr_t)res->start; spi->irq = platform_get_irq(pdev, 0); if (spi->irq <= 0) { dev_err(&pdev->dev, "no irq: %d\n", spi->irq); ret = -ENOENT; goto err_master_put; } ret = devm_request_threaded_irq(&pdev->dev, spi->irq, NULL, stm32_spi_irq, IRQF_ONESHOT, pdev->name, master); if (ret) { dev_err(&pdev->dev, "irq%d request failed: %d\n", spi->irq, ret); goto err_master_put; } spi->clk = devm_clk_get(&pdev->dev, 0); if (IS_ERR(spi->clk)) { ret = PTR_ERR(spi->clk); dev_err(&pdev->dev, "clk get failed: %d\n", ret); goto err_master_put; } ret = clk_prepare_enable(spi->clk); if (ret) { dev_err(&pdev->dev, "clk enable failed: %d\n", ret); goto err_master_put; } spi->clk_rate = clk_get_rate(spi->clk); if (!spi->clk_rate) { dev_err(&pdev->dev, "clk rate = 0\n"); ret = -EINVAL; goto err_master_put; } spi->rst = devm_reset_control_get_exclusive(&pdev->dev, NULL); if (!IS_ERR(spi->rst)) { reset_control_assert(spi->rst); udelay(2); reset_control_deassert(spi->rst); } spi->fifo_size = stm32_spi_get_fifo_size(spi); ret = stm32_spi_config(spi); if (ret) { dev_err(&pdev->dev, "controller configuration failed: %d\n", ret); goto err_clk_disable; } master->dev.of_node = pdev->dev.of_node; master->auto_runtime_pm = true; master->bus_num = pdev->id; master->mode_bits = SPI_MODE_3 | SPI_CS_HIGH | SPI_LSB_FIRST | SPI_3WIRE | SPI_LOOP; master->bits_per_word_mask = stm32_spi_get_bpw_mask(spi); master->max_speed_hz = spi->clk_rate / SPI_MBR_DIV_MIN; master->min_speed_hz = spi->clk_rate / SPI_MBR_DIV_MAX; master->setup = stm32_spi_setup; master->prepare_message = stm32_spi_prepare_msg; master->transfer_one = stm32_spi_transfer_one; master->unprepare_message = stm32_spi_unprepare_msg; spi->dma_tx = dma_request_slave_channel(spi->dev, "tx"); if (!spi->dma_tx) dev_warn(&pdev->dev, "failed to request tx dma channel\n"); else master->dma_tx = spi->dma_tx; spi->dma_rx = dma_request_slave_channel(spi->dev, "rx"); if (!spi->dma_rx) dev_warn(&pdev->dev, "failed to request rx dma channel\n"); else master->dma_rx = spi->dma_rx; if (spi->dma_tx || spi->dma_rx) master->can_dma = stm32_spi_can_dma; pm_runtime_set_active(&pdev->dev); pm_runtime_enable(&pdev->dev); ret = devm_spi_register_master(&pdev->dev, master); if (ret) { dev_err(&pdev->dev, "spi master registration failed: %d\n", ret); goto err_dma_release; } if (!master->cs_gpios) { dev_err(&pdev->dev, "no CS gpios available\n"); ret = -EINVAL; goto err_dma_release; } for (i = 0; i < master->num_chipselect; i++) { if (!gpio_is_valid(master->cs_gpios[i])) { dev_err(&pdev->dev, "%i is not a valid gpio\n", master->cs_gpios[i]); ret = -EINVAL; goto err_dma_release; } ret = devm_gpio_request(&pdev->dev, master->cs_gpios[i], DRIVER_NAME); if (ret) { dev_err(&pdev->dev, "can't get CS gpio %i\n", master->cs_gpios[i]); goto err_dma_release; } } dev_info(&pdev->dev, "driver initialized\n"); return 0; err_dma_release: if (spi->dma_tx) dma_release_channel(spi->dma_tx); if (spi->dma_rx) dma_release_channel(spi->dma_rx); pm_runtime_disable(&pdev->dev); err_clk_disable: clk_disable_unprepare(spi->clk); err_master_put: spi_master_put(master); return ret; }

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static int stm32_spi_remove(struct platform_device *pdev) { struct spi_master *master = platform_get_drvdata(pdev); struct stm32_spi *spi = spi_master_get_devdata(master); stm32_spi_disable(spi); if (master->dma_tx) dma_release_channel(master->dma_tx); if (master->dma_rx) dma_release_channel(master->dma_rx); clk_disable_unprepare(spi->clk); pm_runtime_disable(&pdev->dev); return 0; }

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#ifdef CONFIG_PM
static int stm32_spi_runtime_suspend(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct stm32_spi *spi = spi_master_get_devdata(master); clk_disable_unprepare(spi->clk); return 0; }

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static int stm32_spi_runtime_resume(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct stm32_spi *spi = spi_master_get_devdata(master); return clk_prepare_enable(spi->clk); }

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#endif #ifdef CONFIG_PM_SLEEP
static int stm32_spi_suspend(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); int ret; ret = spi_master_suspend(master); if (ret) return ret; return pm_runtime_force_suspend(dev); }

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static int stm32_spi_resume(struct device *dev) { struct spi_master *master = dev_get_drvdata(dev); struct stm32_spi *spi = spi_master_get_devdata(master); int ret; ret = pm_runtime_force_resume(dev); if (ret) return ret; ret = spi_master_resume(master); if (ret) clk_disable_unprepare(spi->clk); return ret; }

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#endif static const struct dev_pm_ops stm32_spi_pm_ops = { SET_SYSTEM_SLEEP_PM_OPS(stm32_spi_suspend, stm32_spi_resume) SET_RUNTIME_PM_OPS(stm32_spi_runtime_suspend, stm32_spi_runtime_resume, NULL) }; static struct platform_driver stm32_spi_driver = { .probe = stm32_spi_probe, .remove = stm32_spi_remove, .driver = { .name = DRIVER_NAME, .pm = &stm32_spi_pm_ops, .of_match_table = stm32_spi_of_match, }, }; module_platform_driver(stm32_spi_driver); MODULE_ALIAS("platform:" DRIVER_NAME); MODULE_DESCRIPTION("STMicroelectronics STM32 SPI Controller driver"); MODULE_AUTHOR("Amelie Delaunay <amelie.delaunay@st.com>"); MODULE_LICENSE("GPL v2");

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Directory: drivers/spi
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