diff --git a/drivers/spi/spi-stm32.c b/drivers/spi/spi-stm32.c index 8b10074cc75f..4186ed20d796 100644 --- a/drivers/spi/spi-stm32.c +++ b/drivers/spi/spi-stm32.c @@ -20,6 +20,59 @@ #define DRIVER_NAME "spi_stm32" +/* STM32F4 SPI registers */ +#define STM32F4_SPI_CR1 0x00 +#define STM32F4_SPI_CR2 0x04 +#define STM32F4_SPI_SR 0x08 +#define STM32F4_SPI_DR 0x0C +#define STM32F4_SPI_I2SCFGR 0x1C + +/* STM32F4_SPI_CR1 bit fields */ +#define STM32F4_SPI_CR1_CPHA BIT(0) +#define STM32F4_SPI_CR1_CPOL BIT(1) +#define STM32F4_SPI_CR1_MSTR BIT(2) +#define STM32F4_SPI_CR1_BR_SHIFT 3 +#define STM32F4_SPI_CR1_BR GENMASK(5, 3) +#define STM32F4_SPI_CR1_SPE BIT(6) +#define STM32F4_SPI_CR1_LSBFRST BIT(7) +#define STM32F4_SPI_CR1_SSI BIT(8) +#define STM32F4_SPI_CR1_SSM BIT(9) +#define STM32F4_SPI_CR1_RXONLY BIT(10) +#define STM32F4_SPI_CR1_DFF BIT(11) +#define STM32F4_SPI_CR1_CRCNEXT BIT(12) +#define STM32F4_SPI_CR1_CRCEN BIT(13) +#define STM32F4_SPI_CR1_BIDIOE BIT(14) +#define STM32F4_SPI_CR1_BIDIMODE BIT(15) +#define STM32F4_SPI_CR1_BR_MIN 0 +#define STM32F4_SPI_CR1_BR_MAX (GENMASK(5, 3) >> 3) + +/* STM32F4_SPI_CR2 bit fields */ +#define STM32F4_SPI_CR2_RXDMAEN BIT(0) +#define STM32F4_SPI_CR2_TXDMAEN BIT(1) +#define STM32F4_SPI_CR2_SSOE BIT(2) +#define STM32F4_SPI_CR2_FRF BIT(4) +#define STM32F4_SPI_CR2_ERRIE BIT(5) +#define STM32F4_SPI_CR2_RXNEIE BIT(6) +#define STM32F4_SPI_CR2_TXEIE BIT(7) + +/* STM32F4_SPI_SR bit fields */ +#define STM32F4_SPI_SR_RXNE BIT(0) +#define STM32F4_SPI_SR_TXE BIT(1) +#define STM32F4_SPI_SR_CHSIDE BIT(2) +#define STM32F4_SPI_SR_UDR BIT(3) +#define STM32F4_SPI_SR_CRCERR BIT(4) +#define STM32F4_SPI_SR_MODF BIT(5) +#define STM32F4_SPI_SR_OVR BIT(6) +#define STM32F4_SPI_SR_BSY BIT(7) +#define STM32F4_SPI_SR_FRE BIT(8) + +/* STM32F4_SPI_I2SCFGR bit fields */ +#define STM32F4_SPI_I2SCFGR_I2SMOD BIT(11) + +/* STM32F4 SPI Baud Rate min/max divisor */ +#define STM32F4_SPI_BR_DIV_MIN (2 << STM32F4_SPI_CR1_BR_MIN) +#define STM32F4_SPI_BR_DIV_MAX (2 << STM32F4_SPI_CR1_BR_MAX) + /* STM32H7 SPI registers */ #define STM32H7_SPI_CR1 0x00 #define STM32H7_SPI_CR2 0x04 @@ -116,6 +169,12 @@ #define SPI_1HZ_NS 1000000000 +/* + * use PIO for small transfers, avoiding DMA setup/teardown overhead for drivers + * without fifo buffers. + */ +#define SPI_DMA_MIN_BYTES 16 + /** * stm32_spi_reg - stm32 SPI register & bitfield desc * @reg: register offset @@ -257,6 +316,21 @@ struct stm32_spi { dma_addr_t phys_addr; }; +static const struct stm32_spi_regspec stm32f4_spi_regspec = { + .en = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_SPE }, + + .dma_rx_en = { STM32F4_SPI_CR2, STM32F4_SPI_CR2_RXDMAEN }, + .dma_tx_en = { STM32F4_SPI_CR2, STM32F4_SPI_CR2_TXDMAEN }, + + .cpol = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_CPOL }, + .cpha = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_CPHA }, + .lsb_first = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_LSBFRST }, + .br = { STM32F4_SPI_CR1, STM32F4_SPI_CR1_BR, STM32F4_SPI_CR1_BR_SHIFT }, + + .rx = { STM32F4_SPI_DR }, + .tx = { STM32F4_SPI_DR }, +}; + static const struct stm32_spi_regspec stm32h7_spi_regspec = { /* SPI data transfer is enabled but spi_ker_ck is idle. * CFG1 and CFG2 registers are write protected when SPE is enabled. @@ -315,6 +389,16 @@ static int stm32h7_spi_get_fifo_size(struct stm32_spi *spi) return count; } +/** + * stm32f4_spi_get_bpw_mask - Return bits per word mask + * @spi: pointer to the spi controller data structure + */ +static int stm32f4_spi_get_bpw_mask(struct stm32_spi *spi) +{ + dev_dbg(spi->dev, "8-bit or 16-bit data frame supported\n"); + return SPI_BPW_MASK(8) | SPI_BPW_MASK(16); +} + /** * stm32h7_spi_get_bpw_mask - Return bits per word mask * @spi: pointer to the spi controller data structure @@ -408,6 +492,35 @@ static u32 stm32h7_spi_prepare_fthlv(struct stm32_spi *spi) return fthlv; } +/** + * stm32f4_spi_write_tx - Write bytes to 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 stm32f4_spi_write_tx(struct stm32_spi *spi) +{ + if ((spi->tx_len > 0) && (readl_relaxed(spi->base + STM32F4_SPI_SR) & + STM32F4_SPI_SR_TXE)) { + u32 offs = spi->cur_xferlen - spi->tx_len; + + if (spi->cur_bpw == 16) { + const u16 *tx_buf16 = (const u16 *)(spi->tx_buf + offs); + + writew_relaxed(*tx_buf16, spi->base + STM32F4_SPI_DR); + spi->tx_len -= sizeof(u16); + } else { + const u8 *tx_buf8 = (const u8 *)(spi->tx_buf + offs); + + writeb_relaxed(*tx_buf8, spi->base + STM32F4_SPI_DR); + spi->tx_len -= sizeof(u8); + } + } + + dev_dbg(spi->dev, "%s: %d bytes left\n", __func__, spi->tx_len); +} + /** * stm32h7_spi_write_txfifo - Write bytes in Transmit Data Register * @spi: pointer to the spi controller data structure @@ -443,6 +556,35 @@ static void stm32h7_spi_write_txfifo(struct stm32_spi *spi) dev_dbg(spi->dev, "%s: %d bytes left\n", __func__, spi->tx_len); } +/** + * stm32f4_spi_read_rx - Read bytes from 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 stm32f4_spi_read_rx(struct stm32_spi *spi) +{ + if ((spi->rx_len > 0) && (readl_relaxed(spi->base + STM32F4_SPI_SR) & + STM32F4_SPI_SR_RXNE)) { + u32 offs = spi->cur_xferlen - spi->rx_len; + + if (spi->cur_bpw == 16) { + u16 *rx_buf16 = (u16 *)(spi->rx_buf + offs); + + *rx_buf16 = readw_relaxed(spi->base + STM32F4_SPI_DR); + spi->rx_len -= sizeof(u16); + } else { + u8 *rx_buf8 = (u8 *)(spi->rx_buf + offs); + + *rx_buf8 = readb_relaxed(spi->base + STM32F4_SPI_DR); + spi->rx_len -= sizeof(u8); + } + } + + dev_dbg(spi->dev, "%s: %d bytes left\n", __func__, spi->rx_len); +} + /** * stm32h7_spi_read_rxfifo - Read bytes in Receive Data Register * @spi: pointer to the spi controller data structure @@ -501,6 +643,54 @@ static void stm32_spi_enable(struct stm32_spi *spi) spi->cfg->regs->en.mask); } +/** + * stm32f4_spi_disable - Disable SPI controller + * @spi: pointer to the spi controller data structure + */ +static void stm32f4_spi_disable(struct stm32_spi *spi) +{ + unsigned long flags; + u32 sr; + + dev_dbg(spi->dev, "disable controller\n"); + + spin_lock_irqsave(&spi->lock, flags); + + if (!(readl_relaxed(spi->base + STM32F4_SPI_CR1) & + STM32F4_SPI_CR1_SPE)) { + spin_unlock_irqrestore(&spi->lock, flags); + return; + } + + /* Disable interrupts */ + stm32_spi_clr_bits(spi, STM32F4_SPI_CR2, STM32F4_SPI_CR2_TXEIE | + STM32F4_SPI_CR2_RXNEIE | + STM32F4_SPI_CR2_ERRIE); + + /* Wait until BSY = 0 */ + if (readl_relaxed_poll_timeout_atomic(spi->base + STM32F4_SPI_SR, + sr, !(sr & STM32F4_SPI_SR_BSY), + 10, 100000) < 0) { + dev_warn(spi->dev, "disabling condition timeout\n"); + } + + if (spi->cur_usedma && spi->dma_tx) + dmaengine_terminate_all(spi->dma_tx); + if (spi->cur_usedma && spi->dma_rx) + dmaengine_terminate_all(spi->dma_rx); + + stm32_spi_clr_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_SPE); + + stm32_spi_clr_bits(spi, STM32F4_SPI_CR2, STM32F4_SPI_CR2_TXDMAEN | + STM32F4_SPI_CR2_RXDMAEN); + + /* Sequence to clear OVR flag */ + readl_relaxed(spi->base + STM32F4_SPI_DR); + readl_relaxed(spi->base + STM32F4_SPI_SR); + + spin_unlock_irqrestore(&spi->lock, flags); +} + /** * stm32h7_spi_disable - Disable SPI controller * @spi: pointer to the spi controller data structure @@ -568,18 +758,128 @@ static void stm32h7_spi_disable(struct stm32_spi *spi) /** * 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. + * If driver has fifo and the current transfer size is greater than fifo size, + * use DMA. Otherwise use DMA for transfer longer than defined DMA min bytes. */ static bool stm32_spi_can_dma(struct spi_master *master, struct spi_device *spi_dev, struct spi_transfer *transfer) { + unsigned int dma_size; struct stm32_spi *spi = spi_master_get_devdata(master); - dev_dbg(spi->dev, "%s: %s\n", __func__, - (transfer->len > spi->fifo_size) ? "true" : "false"); + if (spi->cfg->has_fifo) + dma_size = spi->fifo_size; + else + dma_size = SPI_DMA_MIN_BYTES; - return (transfer->len > spi->fifo_size); + dev_dbg(spi->dev, "%s: %s\n", __func__, + (transfer->len > dma_size) ? "true" : "false"); + + return (transfer->len > dma_size); +} + +/** + * stm32f4_spi_irq_event - Interrupt handler for SPI controller events + * @irq: interrupt line + * @dev_id: SPI controller master interface + */ +static irqreturn_t stm32f4_spi_irq_event(int irq, void *dev_id) +{ + struct spi_master *master = dev_id; + struct stm32_spi *spi = spi_master_get_devdata(master); + u32 sr, mask = 0; + unsigned long flags; + bool end = false; + + spin_lock_irqsave(&spi->lock, flags); + + sr = readl_relaxed(spi->base + STM32F4_SPI_SR); + /* + * BSY flag is not handled in interrupt but it is normal behavior when + * this flag is set. + */ + sr &= ~STM32F4_SPI_SR_BSY; + + if (!spi->cur_usedma && (spi->cur_comm == SPI_SIMPLEX_TX || + spi->cur_comm == SPI_3WIRE_TX)) { + /* OVR flag shouldn't be handled for TX only mode */ + sr &= ~STM32F4_SPI_SR_OVR | STM32F4_SPI_SR_RXNE; + mask |= STM32F4_SPI_SR_TXE; + } + + if (!spi->cur_usedma && spi->cur_comm == SPI_FULL_DUPLEX) { + /* TXE flag is set and is handled when RXNE flag occurs */ + sr &= ~STM32F4_SPI_SR_TXE; + mask |= STM32F4_SPI_SR_RXNE | STM32F4_SPI_SR_OVR; + } + + if (!(sr & mask)) { + dev_dbg(spi->dev, "spurious IT (sr=0x%08x)\n", sr); + spin_unlock_irqrestore(&spi->lock, flags); + return IRQ_NONE; + } + + if (sr & STM32F4_SPI_SR_OVR) { + dev_warn(spi->dev, "Overrun: received value discarded\n"); + + /* Sequence to clear OVR flag */ + readl_relaxed(spi->base + STM32F4_SPI_DR); + readl_relaxed(spi->base + STM32F4_SPI_SR); + + /* + * If overrun is detected, it means that something went wrong, + * so stop the current transfer. Transfer can wait for next + * RXNE but DR is already read and end never happens. + */ + end = true; + goto end_irq; + } + + if (sr & STM32F4_SPI_SR_TXE) { + if (spi->tx_buf) + stm32f4_spi_write_tx(spi); + if (spi->tx_len == 0) + end = true; + } + + if (sr & STM32F4_SPI_SR_RXNE) { + stm32f4_spi_read_rx(spi); + if (spi->rx_len == 0) + end = true; + else /* Load data for discontinuous mode */ + stm32f4_spi_write_tx(spi); + } + +end_irq: + if (end) { + /* Immediately disable interrupts to do not generate new one */ + stm32_spi_clr_bits(spi, STM32F4_SPI_CR2, + STM32F4_SPI_CR2_TXEIE | + STM32F4_SPI_CR2_RXNEIE | + STM32F4_SPI_CR2_ERRIE); + spin_unlock_irqrestore(&spi->lock, flags); + return IRQ_WAKE_THREAD; + } + + spin_unlock_irqrestore(&spi->lock, flags); + return IRQ_HANDLED; +} + +/** + * stm32f4_spi_irq_thread - Thread of interrupt handler for SPI controller + * @irq: interrupt line + * @dev_id: SPI controller master interface + */ +static irqreturn_t stm32f4_spi_irq_thread(int irq, void *dev_id) +{ + struct spi_master *master = dev_id; + struct stm32_spi *spi = spi_master_get_devdata(master); + + spi_finalize_current_transfer(master); + stm32f4_spi_disable(spi); + + return IRQ_HANDLED; } /** @@ -748,6 +1048,34 @@ static int stm32_spi_prepare_msg(struct spi_master *master, return 0; } +/** + * stm32f4_spi_dma_tx_cb - dma callback + * + * DMA callback is called when the transfer is complete for DMA TX channel. + */ +static void stm32f4_spi_dma_tx_cb(void *data) +{ + struct stm32_spi *spi = data; + + if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX) { + spi_finalize_current_transfer(spi->master); + stm32f4_spi_disable(spi); + } +} + +/** + * stm32f4_spi_dma_rx_cb - dma callback + * + * DMA callback is called when the transfer is complete for DMA RX channel. + */ +static void stm32f4_spi_dma_rx_cb(void *data) +{ + struct stm32_spi *spi = data; + + spi_finalize_current_transfer(spi->master); + stm32f4_spi_disable(spi); +} + /** * stm32h7_spi_dma_cb - dma callback * @@ -790,11 +1118,15 @@ static void stm32_spi_dma_config(struct stm32_spi *spi, else buswidth = DMA_SLAVE_BUSWIDTH_4_BYTES; - /* Valid for DMA Half or Full Fifo threshold */ - if (spi->cur_fthlv == 2) + if (spi->cfg->has_fifo) { + /* Valid for DMA Half or Full Fifo threshold */ + if (spi->cur_fthlv == 2) + maxburst = 1; + else + maxburst = spi->cur_fthlv; + } else { maxburst = 1; - else - maxburst = spi->cur_fthlv; + } memset(dma_conf, 0, sizeof(struct dma_slave_config)); dma_conf->direction = dir; @@ -815,6 +1147,46 @@ static void stm32_spi_dma_config(struct stm32_spi *spi, } } +/** + * stm32f4_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 stm32f4_spi_transfer_one_irq(struct stm32_spi *spi) +{ + unsigned long flags; + u32 cr2 = 0; + + /* Enable the interrupts relative to the current communication mode */ + if (spi->cur_comm == SPI_SIMPLEX_TX || spi->cur_comm == SPI_3WIRE_TX) { + cr2 |= STM32F4_SPI_CR2_TXEIE; + } else if (spi->cur_comm == SPI_FULL_DUPLEX) { + /* In transmit-only mode, the OVR flag is set in the SR register + * since the received data are never read. Therefore set OVR + * interrupt only when rx buffer is available. + */ + cr2 |= STM32F4_SPI_CR2_RXNEIE | STM32F4_SPI_CR2_ERRIE; + } else { + return -EINVAL; + } + + spin_lock_irqsave(&spi->lock, flags); + + stm32_spi_set_bits(spi, STM32F4_SPI_CR2, cr2); + + stm32_spi_enable(spi); + + /* starting data transfer when buffer is loaded */ + if (spi->tx_buf) + stm32f4_spi_write_tx(spi); + + spin_unlock_irqrestore(&spi->lock, flags); + + return 1; +} + /** * stm32h7_spi_transfer_one_irq - transfer a single spi_transfer using * interrupts @@ -856,6 +1228,26 @@ static int stm32h7_spi_transfer_one_irq(struct stm32_spi *spi) return 1; } +/** + * stm32f4_spi_transfer_one_dma_start - Set SPI driver registers to start + * transfer using DMA + */ +static void stm32f4_spi_transfer_one_dma_start(struct stm32_spi *spi) +{ + /* In DMA mode end of transfer is handled by DMA TX or RX callback. */ + if (spi->cur_comm == SPI_SIMPLEX_RX || spi->cur_comm == SPI_3WIRE_RX || + spi->cur_comm == SPI_FULL_DUPLEX) { + /* + * In transmit-only mode, the OVR flag is set in the SR register + * since the received data are never read. Therefore set OVR + * interrupt only when rx buffer is available. + */ + stm32_spi_set_bits(spi, STM32F4_SPI_CR2, STM32F4_SPI_CR2_ERRIE); + } + + stm32_spi_enable(spi); +} + /** * stm32h7_spi_transfer_one_dma_start - Set SPI driver registers to start * transfer using DMA @@ -976,6 +1368,18 @@ dma_desc_error: return spi->cfg->transfer_one_irq(spi); } +/** + * stm32f4_spi_set_bpw - Configure bits per word + * @spi: pointer to the spi controller data structure + */ +static void stm32f4_spi_set_bpw(struct stm32_spi *spi) +{ + if (spi->cur_bpw == 16) + stm32_spi_set_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_DFF); + else + stm32_spi_clr_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_DFF); +} + /** * stm32h7_spi_set_bpw - configure bits per word * @spi: pointer to the spi controller data structure @@ -1053,6 +1457,28 @@ static unsigned int stm32_spi_communication_type(struct spi_device *spi_dev, return type; } +/** + * stm32f4_spi_set_mode - configure communication mode + * @spi: pointer to the spi controller data structure + * @comm_type: type of communication to configure + */ +static int stm32f4_spi_set_mode(struct stm32_spi *spi, unsigned int comm_type) +{ + if (comm_type == SPI_3WIRE_TX || comm_type == SPI_SIMPLEX_TX) { + stm32_spi_set_bits(spi, STM32F4_SPI_CR1, + STM32F4_SPI_CR1_BIDIMODE | + STM32F4_SPI_CR1_BIDIOE); + } else if (comm_type == SPI_FULL_DUPLEX) { + stm32_spi_clr_bits(spi, STM32F4_SPI_CR1, + STM32F4_SPI_CR1_BIDIMODE | + STM32F4_SPI_CR1_BIDIOE); + } else { + return -EINVAL; + } + + return 0; +} + /** * stm32h7_spi_set_mode - configure communication mode * @spi: pointer to the spi controller data structure @@ -1267,6 +1693,36 @@ static int stm32_spi_unprepare_msg(struct spi_master *master, return 0; } +/** + * stm32f4_spi_config - Configure SPI controller as SPI master + */ +static int stm32f4_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, STM32F4_SPI_I2SCFGR, + STM32F4_SPI_I2SCFGR_I2SMOD); + + /* + * - SS input value high + * - transmitter half duplex direction + * - Set the master mode (default Motorola mode) + * - Consider 1 master/n slaves configuration and + * SS input value is determined by the SSI bit + */ + stm32_spi_set_bits(spi, STM32F4_SPI_CR1, STM32F4_SPI_CR1_SSI | + STM32F4_SPI_CR1_BIDIOE | + STM32F4_SPI_CR1_MSTR | + STM32F4_SPI_CR1_SSM); + + spin_unlock_irqrestore(&spi->lock, flags); + + return 0; +} + /** * stm32h7_spi_config - Configure SPI controller as SPI master */ @@ -1304,6 +1760,24 @@ static int stm32h7_spi_config(struct stm32_spi *spi) return 0; } +static const struct stm32_spi_cfg stm32f4_spi_cfg = { + .regs = &stm32f4_spi_regspec, + .get_bpw_mask = stm32f4_spi_get_bpw_mask, + .disable = stm32f4_spi_disable, + .config = stm32f4_spi_config, + .set_bpw = stm32f4_spi_set_bpw, + .set_mode = stm32f4_spi_set_mode, + .transfer_one_dma_start = stm32f4_spi_transfer_one_dma_start, + .dma_tx_cb = stm32f4_spi_dma_tx_cb, + .dma_rx_cb = stm32f4_spi_dma_rx_cb, + .transfer_one_irq = stm32f4_spi_transfer_one_irq, + .irq_handler_event = stm32f4_spi_irq_event, + .irq_handler_thread = stm32f4_spi_irq_thread, + .baud_rate_div_min = STM32F4_SPI_BR_DIV_MIN, + .baud_rate_div_max = STM32F4_SPI_BR_DIV_MAX, + .has_fifo = false, +}; + static const struct stm32_spi_cfg stm32h7_spi_cfg = { .regs = &stm32h7_spi_regspec, .get_fifo_size = stm32h7_spi_get_fifo_size, @@ -1326,6 +1800,7 @@ static const struct stm32_spi_cfg stm32h7_spi_cfg = { static const struct of_device_id stm32_spi_of_match[] = { { .compatible = "st,stm32h7-spi", .data = (void *)&stm32h7_spi_cfg }, + { .compatible = "st,stm32f4-spi", .data = (void *)&stm32f4_spi_cfg }, {}, }; MODULE_DEVICE_TABLE(of, stm32_spi_of_match);