The STM32 Serial Peripheral Interface (SPI) can be used to communicate with external devices while using the specific synchronous protocol. It supports a half-duplex, full-duplex and simplex synchronous, serial communication with external devices with 4-bit to 16/32-bit per word. It has two 8x/16x 8-bit embedded Rx and TxFIFOs with DMA capability. It can operate in master or slave mode. Signed-off-by: Amelie Delaunay <amelie.delaunay@xxxxxx> --- drivers/spi/Kconfig | 10 + drivers/spi/Makefile | 1 + drivers/spi/spi-stm32.c | 1266 +++++++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 1277 insertions(+) create mode 100644 drivers/spi/spi-stm32.c diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index fd1b4fd..9b31351 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -627,6 +627,16 @@ config SPI_SIRF help SPI driver for CSR SiRFprimaII SoCs +config SPI_STM32 + tristate "STMicroelectronics STM32 SPI controller" + depends on ARCH_STM32 || COMPILE_TEST + help + SPI driver for STMicroelectonics STM32 SoCs. + + STM32 SPI controller supports DMA and PIO modes. When DMA + is not available, the driver automatically falls back to + PIO mode. + config SPI_ST_SSC4 tristate "STMicroelectronics SPI SSC-based driver" depends on ARCH_STI || COMPILE_TEST diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 31dccfb..a3ae2b7 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -90,6 +90,7 @@ obj-$(CONFIG_SPI_SH_HSPI) += spi-sh-hspi.o obj-$(CONFIG_SPI_SH_MSIOF) += spi-sh-msiof.o obj-$(CONFIG_SPI_SH_SCI) += spi-sh-sci.o obj-$(CONFIG_SPI_SIRF) += spi-sirf.o +obj-$(CONFIG_SPI_STM32) += spi-stm32.o obj-$(CONFIG_SPI_ST_SSC4) += spi-st-ssc4.o obj-$(CONFIG_SPI_SUN4I) += spi-sun4i.o obj-$(CONFIG_SPI_SUN6I) += spi-sun6i.o diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c new file mode 100644 index 0000000..0553f61 --- /dev/null +++ b/drivers/spi/spi-stm32.c @@ -0,0 +1,1266 @@ +/* + * STMicroelectronics STM32 SPI Controller driver (master mode only) + * + * Copyright (C) 2017, STMicroelectronics - All Rights Reserved + * Author(s): Amelie Delaunay <amelie.delaunay@xxxxxx> 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/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); +} + +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); +} + +/** + * 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; +} + +/** + * 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); +} + +/** + * 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 */ + mbrdiv = (div & (div - 1)) ? fls(div) : fls(div) - 1; + + spi->cur_speed = spi->clk_rate / (1 << mbrdiv); + + return mbrdiv - 1; +} + +/** + * 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); + + fthlv = (spi->cur_bpw <= 8) ? half_fifo : + (spi->cur_bpw <= 16) ? (half_fifo / 2) : + (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; +} + +/** + * 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); +} + +/** + * 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); +} + +/** + * 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); +} + +/** + * 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); +} + +/** + * 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); +} + +/** + * 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. + */ + mask |= ((spi->rx_buf && !spi->cur_usedma) ? SPI_SR_RXP : 0); + + 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 (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 (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; +} + +/** + * 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; +} + +/** + * 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", &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; +} + +/** + * 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 callback (sr=0x%08x)\n", sr); + + spi_finalize_current_transfer(spi->master); + stm32_spi_disable(spi); + } +} + +/** + * 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; + + buswidth = (spi->cur_bpw <= 8) ? DMA_SLAVE_BUSWIDTH_1_BYTE : + (spi->cur_bpw <= 16) ? DMA_SLAVE_BUSWIDTH_2_BYTES : + DMA_SLAVE_BUSWIDTH_4_BYTES; + + /* Valid for DMA Half or Full Fifo threshold */ + maxburst = (spi->cur_fthlv == 2) ? 1 : 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); + } +} + +/** + * 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; +} + +/** + * 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); + + rx_dma_desc->callback = stm32_spi_dma_cb; + rx_dma_desc->callback_param = spi; + } + + 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->cur_comm == SPI_SIMPLEX_TX) { + tx_dma_desc->callback = stm32_spi_dma_cb; + tx_dma_desc->callback_param = spi; + } + } + + if ((spi->tx_buf && !tx_dma_desc) || + (spi->rx_buf && !rx_dma_desc)) + goto dma_desc_error; + + if (rx_dma_desc) { + 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 (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); +} + +/** + * 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) { + u32 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 |= (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); + + nb_words = DIV_ROUND_UP(transfer->len * 8, + (spi->cur_bpw <= 8) ? 8 : + (spi->cur_bpw <= 16) ? 16 : 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; +} + +/** + * 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 = 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); +} + +/** + * 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; +} + +/** + * 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; +} + +static const struct of_device_id stm32_spi_of_match[] = { + { .compatible = "st,stm32-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(&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; + + 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); +err_clk_disable: + clk_disable_unprepare(spi->clk); +err_master_put: + spi_master_put(master); + + return ret; +} + +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); + + return 0; +} + +#ifdef CONFIG_PM_SLEEP +static int stm32_spi_suspend(struct device *dev) +{ + struct spi_master *master = dev_get_drvdata(dev); + struct stm32_spi *spi = spi_master_get_devdata(master); + int ret; + + ret = spi_master_suspend(master); + if (ret) + return ret; + + clk_disable_unprepare(spi->clk); + + return ret; +} + +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 = clk_prepare_enable(spi->clk); + if (ret) + return ret; + ret = spi_master_resume(master); + if (ret) + clk_disable_unprepare(spi->clk); + + return ret; +} +#endif + +static SIMPLE_DEV_PM_OPS(stm32_spi_pm_ops, + stm32_spi_suspend, stm32_spi_resume); + +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@xxxxxx>"); +MODULE_LICENSE("GPL v2"); -- 1.9.1 -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
