diff options
Diffstat (limited to 'drivers/spi/spi-dw-core.c')
| -rw-r--r-- | drivers/spi/spi-dw-core.c | 1017 |
1 files changed, 1017 insertions, 0 deletions
diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c new file mode 100644 index 000000000..4976e3b89 --- /dev/null +++ b/drivers/spi/spi-dw-core.c @@ -0,0 +1,1017 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Designware SPI core controller driver (refer pxa2xx_spi.c) + * + * Copyright (c) 2009, Intel Corporation. + */ + +#include <linux/bitfield.h> +#include <linux/dma-mapping.h> +#include <linux/interrupt.h> +#include <linux/module.h> +#include <linux/preempt.h> +#include <linux/highmem.h> +#include <linux/delay.h> +#include <linux/slab.h> +#include <linux/spi/spi.h> +#include <linux/spi/spi-mem.h> +#include <linux/string.h> +#include <linux/of.h> + +#include "spi-dw.h" + +#ifdef CONFIG_DEBUG_FS +#include <linux/debugfs.h> +#endif + +/* Slave spi_device related */ +struct dw_spi_chip_data { + u32 cr0; + u32 rx_sample_dly; /* RX sample delay */ +}; + +#ifdef CONFIG_DEBUG_FS + +#define DW_SPI_DBGFS_REG(_name, _off) \ +{ \ + .name = _name, \ + .offset = _off, \ +} + +static const struct debugfs_reg32 dw_spi_dbgfs_regs[] = { + DW_SPI_DBGFS_REG("CTRLR0", DW_SPI_CTRLR0), + DW_SPI_DBGFS_REG("CTRLR1", DW_SPI_CTRLR1), + DW_SPI_DBGFS_REG("SSIENR", DW_SPI_SSIENR), + DW_SPI_DBGFS_REG("SER", DW_SPI_SER), + DW_SPI_DBGFS_REG("BAUDR", DW_SPI_BAUDR), + DW_SPI_DBGFS_REG("TXFTLR", DW_SPI_TXFTLR), + DW_SPI_DBGFS_REG("RXFTLR", DW_SPI_RXFTLR), + DW_SPI_DBGFS_REG("TXFLR", DW_SPI_TXFLR), + DW_SPI_DBGFS_REG("RXFLR", DW_SPI_RXFLR), + DW_SPI_DBGFS_REG("SR", DW_SPI_SR), + DW_SPI_DBGFS_REG("IMR", DW_SPI_IMR), + DW_SPI_DBGFS_REG("ISR", DW_SPI_ISR), + DW_SPI_DBGFS_REG("DMACR", DW_SPI_DMACR), + DW_SPI_DBGFS_REG("DMATDLR", DW_SPI_DMATDLR), + DW_SPI_DBGFS_REG("DMARDLR", DW_SPI_DMARDLR), + DW_SPI_DBGFS_REG("RX_SAMPLE_DLY", DW_SPI_RX_SAMPLE_DLY), +}; + +static int dw_spi_debugfs_init(struct dw_spi *dws) +{ + char name[32]; + + snprintf(name, 32, "dw_spi%d", dws->master->bus_num); + dws->debugfs = debugfs_create_dir(name, NULL); + if (!dws->debugfs) + return -ENOMEM; + + dws->regset.regs = dw_spi_dbgfs_regs; + dws->regset.nregs = ARRAY_SIZE(dw_spi_dbgfs_regs); + dws->regset.base = dws->regs; + debugfs_create_regset32("registers", 0400, dws->debugfs, &dws->regset); + + return 0; +} + +static void dw_spi_debugfs_remove(struct dw_spi *dws) +{ + debugfs_remove_recursive(dws->debugfs); +} + +#else +static inline int dw_spi_debugfs_init(struct dw_spi *dws) +{ + return 0; +} + +static inline void dw_spi_debugfs_remove(struct dw_spi *dws) +{ +} +#endif /* CONFIG_DEBUG_FS */ + +void dw_spi_set_cs(struct spi_device *spi, bool enable) +{ + struct dw_spi *dws = spi_controller_get_devdata(spi->controller); + bool cs_high = !!(spi->mode & SPI_CS_HIGH); + + /* + * DW SPI controller demands any native CS being set in order to + * proceed with data transfer. So in order to activate the SPI + * communications we must set a corresponding bit in the Slave + * Enable register no matter whether the SPI core is configured to + * support active-high or active-low CS level. + */ + if (cs_high == enable) + dw_writel(dws, DW_SPI_SER, BIT(spi->chip_select)); + else + dw_writel(dws, DW_SPI_SER, 0); +} +EXPORT_SYMBOL_NS_GPL(dw_spi_set_cs, SPI_DW_CORE); + +/* Return the max entries we can fill into tx fifo */ +static inline u32 dw_spi_tx_max(struct dw_spi *dws) +{ + u32 tx_room, rxtx_gap; + + tx_room = dws->fifo_len - dw_readl(dws, DW_SPI_TXFLR); + + /* + * Another concern is about the tx/rx mismatch, we + * though to use (dws->fifo_len - rxflr - txflr) as + * one maximum value for tx, but it doesn't cover the + * data which is out of tx/rx fifo and inside the + * shift registers. So a control from sw point of + * view is taken. + */ + rxtx_gap = dws->fifo_len - (dws->rx_len - dws->tx_len); + + return min3((u32)dws->tx_len, tx_room, rxtx_gap); +} + +/* Return the max entries we should read out of rx fifo */ +static inline u32 dw_spi_rx_max(struct dw_spi *dws) +{ + return min_t(u32, dws->rx_len, dw_readl(dws, DW_SPI_RXFLR)); +} + +static void dw_writer(struct dw_spi *dws) +{ + u32 max = dw_spi_tx_max(dws); + u32 txw = 0; + + while (max--) { + if (dws->tx) { + if (dws->n_bytes == 1) + txw = *(u8 *)(dws->tx); + else if (dws->n_bytes == 2) + txw = *(u16 *)(dws->tx); + else + txw = *(u32 *)(dws->tx); + + dws->tx += dws->n_bytes; + } + dw_write_io_reg(dws, DW_SPI_DR, txw); + --dws->tx_len; + } +} + +static void dw_reader(struct dw_spi *dws) +{ + u32 max = dw_spi_rx_max(dws); + u32 rxw; + + while (max--) { + rxw = dw_read_io_reg(dws, DW_SPI_DR); + if (dws->rx) { + if (dws->n_bytes == 1) + *(u8 *)(dws->rx) = rxw; + else if (dws->n_bytes == 2) + *(u16 *)(dws->rx) = rxw; + else + *(u32 *)(dws->rx) = rxw; + + dws->rx += dws->n_bytes; + } + --dws->rx_len; + } +} + +int dw_spi_check_status(struct dw_spi *dws, bool raw) +{ + u32 irq_status; + int ret = 0; + + if (raw) + irq_status = dw_readl(dws, DW_SPI_RISR); + else + irq_status = dw_readl(dws, DW_SPI_ISR); + + if (irq_status & DW_SPI_INT_RXOI) { + dev_err(&dws->master->dev, "RX FIFO overflow detected\n"); + ret = -EIO; + } + + if (irq_status & DW_SPI_INT_RXUI) { + dev_err(&dws->master->dev, "RX FIFO underflow detected\n"); + ret = -EIO; + } + + if (irq_status & DW_SPI_INT_TXOI) { + dev_err(&dws->master->dev, "TX FIFO overflow detected\n"); + ret = -EIO; + } + + /* Generically handle the erroneous situation */ + if (ret) { + dw_spi_reset_chip(dws); + if (dws->master->cur_msg) + dws->master->cur_msg->status = ret; + } + + return ret; +} +EXPORT_SYMBOL_NS_GPL(dw_spi_check_status, SPI_DW_CORE); + +static irqreturn_t dw_spi_transfer_handler(struct dw_spi *dws) +{ + u16 irq_status = dw_readl(dws, DW_SPI_ISR); + + if (dw_spi_check_status(dws, false)) { + spi_finalize_current_transfer(dws->master); + return IRQ_HANDLED; + } + + /* + * Read data from the Rx FIFO every time we've got a chance executing + * this method. If there is nothing left to receive, terminate the + * procedure. Otherwise adjust the Rx FIFO Threshold level if it's a + * final stage of the transfer. By doing so we'll get the next IRQ + * right when the leftover incoming data is received. + */ + dw_reader(dws); + if (!dws->rx_len) { + dw_spi_mask_intr(dws, 0xff); + spi_finalize_current_transfer(dws->master); + } else if (dws->rx_len <= dw_readl(dws, DW_SPI_RXFTLR)) { + dw_writel(dws, DW_SPI_RXFTLR, dws->rx_len - 1); + } + + /* + * Send data out if Tx FIFO Empty IRQ is received. The IRQ will be + * disabled after the data transmission is finished so not to + * have the TXE IRQ flood at the final stage of the transfer. + */ + if (irq_status & DW_SPI_INT_TXEI) { + dw_writer(dws); + if (!dws->tx_len) + dw_spi_mask_intr(dws, DW_SPI_INT_TXEI); + } + + return IRQ_HANDLED; +} + +static irqreturn_t dw_spi_irq(int irq, void *dev_id) +{ + struct spi_controller *master = dev_id; + struct dw_spi *dws = spi_controller_get_devdata(master); + u16 irq_status = dw_readl(dws, DW_SPI_ISR) & DW_SPI_INT_MASK; + + if (!irq_status) + return IRQ_NONE; + + if (!master->cur_msg) { + dw_spi_mask_intr(dws, 0xff); + return IRQ_HANDLED; + } + + return dws->transfer_handler(dws); +} + +static u32 dw_spi_prepare_cr0(struct dw_spi *dws, struct spi_device *spi) +{ + u32 cr0 = 0; + + if (dw_spi_ip_is(dws, PSSI)) { + /* CTRLR0[ 5: 4] Frame Format */ + cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI); + + /* + * SPI mode (SCPOL|SCPH) + * CTRLR0[ 6] Serial Clock Phase + * CTRLR0[ 7] Serial Clock Polarity + */ + if (spi->mode & SPI_CPOL) + cr0 |= DW_PSSI_CTRLR0_SCPOL; + if (spi->mode & SPI_CPHA) + cr0 |= DW_PSSI_CTRLR0_SCPHA; + + /* CTRLR0[11] Shift Register Loop */ + if (spi->mode & SPI_LOOP) + cr0 |= DW_PSSI_CTRLR0_SRL; + } else { + /* CTRLR0[ 7: 6] Frame Format */ + cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_FRF_MASK, DW_SPI_CTRLR0_FRF_MOTO_SPI); + + /* + * SPI mode (SCPOL|SCPH) + * CTRLR0[ 8] Serial Clock Phase + * CTRLR0[ 9] Serial Clock Polarity + */ + if (spi->mode & SPI_CPOL) + cr0 |= DW_HSSI_CTRLR0_SCPOL; + if (spi->mode & SPI_CPHA) + cr0 |= DW_HSSI_CTRLR0_SCPHA; + + /* CTRLR0[13] Shift Register Loop */ + if (spi->mode & SPI_LOOP) + cr0 |= DW_HSSI_CTRLR0_SRL; + + /* CTRLR0[31] MST */ + if (dw_spi_ver_is_ge(dws, HSSI, 102A)) + cr0 |= DW_HSSI_CTRLR0_MST; + } + + return cr0; +} + +void dw_spi_update_config(struct dw_spi *dws, struct spi_device *spi, + struct dw_spi_cfg *cfg) +{ + struct dw_spi_chip_data *chip = spi_get_ctldata(spi); + u32 cr0 = chip->cr0; + u32 speed_hz; + u16 clk_div; + + /* CTRLR0[ 4/3: 0] or CTRLR0[ 20: 16] Data Frame Size */ + cr0 |= (cfg->dfs - 1) << dws->dfs_offset; + + if (dw_spi_ip_is(dws, PSSI)) + /* CTRLR0[ 9:8] Transfer Mode */ + cr0 |= FIELD_PREP(DW_PSSI_CTRLR0_TMOD_MASK, cfg->tmode); + else + /* CTRLR0[11:10] Transfer Mode */ + cr0 |= FIELD_PREP(DW_HSSI_CTRLR0_TMOD_MASK, cfg->tmode); + + dw_writel(dws, DW_SPI_CTRLR0, cr0); + + if (cfg->tmode == DW_SPI_CTRLR0_TMOD_EPROMREAD || + cfg->tmode == DW_SPI_CTRLR0_TMOD_RO) + dw_writel(dws, DW_SPI_CTRLR1, cfg->ndf ? cfg->ndf - 1 : 0); + + /* Note DW APB SSI clock divider doesn't support odd numbers */ + clk_div = (DIV_ROUND_UP(dws->max_freq, cfg->freq) + 1) & 0xfffe; + speed_hz = dws->max_freq / clk_div; + + if (dws->current_freq != speed_hz) { + dw_spi_set_clk(dws, clk_div); + dws->current_freq = speed_hz; + } + + /* Update RX sample delay if required */ + if (dws->cur_rx_sample_dly != chip->rx_sample_dly) { + dw_writel(dws, DW_SPI_RX_SAMPLE_DLY, chip->rx_sample_dly); + dws->cur_rx_sample_dly = chip->rx_sample_dly; + } +} +EXPORT_SYMBOL_NS_GPL(dw_spi_update_config, SPI_DW_CORE); + +static void dw_spi_irq_setup(struct dw_spi *dws) +{ + u16 level; + u8 imask; + + /* + * Originally Tx and Rx data lengths match. Rx FIFO Threshold level + * will be adjusted at the final stage of the IRQ-based SPI transfer + * execution so not to lose the leftover of the incoming data. + */ + level = min_t(unsigned int, dws->fifo_len / 2, dws->tx_len); + dw_writel(dws, DW_SPI_TXFTLR, level); + dw_writel(dws, DW_SPI_RXFTLR, level - 1); + + dws->transfer_handler = dw_spi_transfer_handler; + + imask = DW_SPI_INT_TXEI | DW_SPI_INT_TXOI | + DW_SPI_INT_RXUI | DW_SPI_INT_RXOI | DW_SPI_INT_RXFI; + dw_spi_umask_intr(dws, imask); +} + +/* + * The iterative procedure of the poll-based transfer is simple: write as much + * as possible to the Tx FIFO, wait until the pending to receive data is ready + * to be read, read it from the Rx FIFO and check whether the performed + * procedure has been successful. + * + * Note this method the same way as the IRQ-based transfer won't work well for + * the SPI devices connected to the controller with native CS due to the + * automatic CS assertion/de-assertion. + */ +static int dw_spi_poll_transfer(struct dw_spi *dws, + struct spi_transfer *transfer) +{ + struct spi_delay delay; + u16 nbits; + int ret; + + delay.unit = SPI_DELAY_UNIT_SCK; + nbits = dws->n_bytes * BITS_PER_BYTE; + + do { + dw_writer(dws); + + delay.value = nbits * (dws->rx_len - dws->tx_len); + spi_delay_exec(&delay, transfer); + + dw_reader(dws); + + ret = dw_spi_check_status(dws, true); + if (ret) + return ret; + } while (dws->rx_len); + + return 0; +} + +static int dw_spi_transfer_one(struct spi_controller *master, + struct spi_device *spi, + struct spi_transfer *transfer) +{ + struct dw_spi *dws = spi_controller_get_devdata(master); + struct dw_spi_cfg cfg = { + .tmode = DW_SPI_CTRLR0_TMOD_TR, + .dfs = transfer->bits_per_word, + .freq = transfer->speed_hz, + }; + int ret; + + dws->dma_mapped = 0; + dws->n_bytes = + roundup_pow_of_two(DIV_ROUND_UP(transfer->bits_per_word, + BITS_PER_BYTE)); + + dws->tx = (void *)transfer->tx_buf; + dws->tx_len = transfer->len / dws->n_bytes; + dws->rx = transfer->rx_buf; + dws->rx_len = dws->tx_len; + + /* Ensure the data above is visible for all CPUs */ + smp_mb(); + + dw_spi_enable_chip(dws, 0); + + dw_spi_update_config(dws, spi, &cfg); + + transfer->effective_speed_hz = dws->current_freq; + + /* Check if current transfer is a DMA transaction */ + if (master->can_dma && master->can_dma(master, spi, transfer)) + dws->dma_mapped = master->cur_msg_mapped; + + /* For poll mode just disable all interrupts */ + dw_spi_mask_intr(dws, 0xff); + + if (dws->dma_mapped) { + ret = dws->dma_ops->dma_setup(dws, transfer); + if (ret) + return ret; + } + + dw_spi_enable_chip(dws, 1); + + if (dws->dma_mapped) + return dws->dma_ops->dma_transfer(dws, transfer); + else if (dws->irq == IRQ_NOTCONNECTED) + return dw_spi_poll_transfer(dws, transfer); + + dw_spi_irq_setup(dws); + + return 1; +} + +static void dw_spi_handle_err(struct spi_controller *master, + struct spi_message *msg) +{ + struct dw_spi *dws = spi_controller_get_devdata(master); + + if (dws->dma_mapped) + dws->dma_ops->dma_stop(dws); + + dw_spi_reset_chip(dws); +} + +static int dw_spi_adjust_mem_op_size(struct spi_mem *mem, struct spi_mem_op *op) +{ + if (op->data.dir == SPI_MEM_DATA_IN) + op->data.nbytes = clamp_val(op->data.nbytes, 0, DW_SPI_NDF_MASK + 1); + + return 0; +} + +static bool dw_spi_supports_mem_op(struct spi_mem *mem, + const struct spi_mem_op *op) +{ + if (op->data.buswidth > 1 || op->addr.buswidth > 1 || + op->dummy.buswidth > 1 || op->cmd.buswidth > 1) + return false; + + return spi_mem_default_supports_op(mem, op); +} + +static int dw_spi_init_mem_buf(struct dw_spi *dws, const struct spi_mem_op *op) +{ + unsigned int i, j, len; + u8 *out; + + /* + * Calculate the total length of the EEPROM command transfer and + * either use the pre-allocated buffer or create a temporary one. + */ + len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes; + if (op->data.dir == SPI_MEM_DATA_OUT) + len += op->data.nbytes; + + if (len <= DW_SPI_BUF_SIZE) { + out = dws->buf; + } else { + out = kzalloc(len, GFP_KERNEL); + if (!out) + return -ENOMEM; + } + + /* + * Collect the operation code, address and dummy bytes into the single + * buffer. If it's a transfer with data to be sent, also copy it into the + * single buffer in order to speed the data transmission up. + */ + for (i = 0; i < op->cmd.nbytes; ++i) + out[i] = DW_SPI_GET_BYTE(op->cmd.opcode, op->cmd.nbytes - i - 1); + for (j = 0; j < op->addr.nbytes; ++i, ++j) + out[i] = DW_SPI_GET_BYTE(op->addr.val, op->addr.nbytes - j - 1); + for (j = 0; j < op->dummy.nbytes; ++i, ++j) + out[i] = 0x0; + + if (op->data.dir == SPI_MEM_DATA_OUT) + memcpy(&out[i], op->data.buf.out, op->data.nbytes); + + dws->n_bytes = 1; + dws->tx = out; + dws->tx_len = len; + if (op->data.dir == SPI_MEM_DATA_IN) { + dws->rx = op->data.buf.in; + dws->rx_len = op->data.nbytes; + } else { + dws->rx = NULL; + dws->rx_len = 0; + } + + return 0; +} + +static void dw_spi_free_mem_buf(struct dw_spi *dws) +{ + if (dws->tx != dws->buf) + kfree(dws->tx); +} + +static int dw_spi_write_then_read(struct dw_spi *dws, struct spi_device *spi) +{ + u32 room, entries, sts; + unsigned int len; + u8 *buf; + + /* + * At initial stage we just pre-fill the Tx FIFO in with no rush, + * since native CS hasn't been enabled yet and the automatic data + * transmission won't start til we do that. + */ + len = min(dws->fifo_len, dws->tx_len); + buf = dws->tx; + while (len--) + dw_write_io_reg(dws, DW_SPI_DR, *buf++); + + /* + * After setting any bit in the SER register the transmission will + * start automatically. We have to keep up with that procedure + * otherwise the CS de-assertion will happen whereupon the memory + * operation will be pre-terminated. + */ + len = dws->tx_len - ((void *)buf - dws->tx); + dw_spi_set_cs(spi, false); + while (len) { + entries = readl_relaxed(dws->regs + DW_SPI_TXFLR); + if (!entries) { + dev_err(&dws->master->dev, "CS de-assertion on Tx\n"); + return -EIO; + } + room = min(dws->fifo_len - entries, len); + for (; room; --room, --len) + dw_write_io_reg(dws, DW_SPI_DR, *buf++); + } + + /* + * Data fetching will start automatically if the EEPROM-read mode is + * activated. We have to keep up with the incoming data pace to + * prevent the Rx FIFO overflow causing the inbound data loss. + */ + len = dws->rx_len; + buf = dws->rx; + while (len) { + entries = readl_relaxed(dws->regs + DW_SPI_RXFLR); + if (!entries) { + sts = readl_relaxed(dws->regs + DW_SPI_RISR); + if (sts & DW_SPI_INT_RXOI) { + dev_err(&dws->master->dev, "FIFO overflow on Rx\n"); + return -EIO; + } + continue; + } + entries = min(entries, len); + for (; entries; --entries, --len) + *buf++ = dw_read_io_reg(dws, DW_SPI_DR); + } + + return 0; +} + +static inline bool dw_spi_ctlr_busy(struct dw_spi *dws) +{ + return dw_readl(dws, DW_SPI_SR) & DW_SPI_SR_BUSY; +} + +static int dw_spi_wait_mem_op_done(struct dw_spi *dws) +{ + int retry = DW_SPI_WAIT_RETRIES; + struct spi_delay delay; + unsigned long ns, us; + u32 nents; + + nents = dw_readl(dws, DW_SPI_TXFLR); + ns = NSEC_PER_SEC / dws->current_freq * nents; + ns *= dws->n_bytes * BITS_PER_BYTE; + if (ns <= NSEC_PER_USEC) { + delay.unit = SPI_DELAY_UNIT_NSECS; + delay.value = ns; + } else { + us = DIV_ROUND_UP(ns, NSEC_PER_USEC); + delay.unit = SPI_DELAY_UNIT_USECS; + delay.value = clamp_val(us, 0, USHRT_MAX); + } + + while (dw_spi_ctlr_busy(dws) && retry--) + spi_delay_exec(&delay, NULL); + + if (retry < 0) { + dev_err(&dws->master->dev, "Mem op hanged up\n"); + return -EIO; + } + + return 0; +} + +static void dw_spi_stop_mem_op(struct dw_spi *dws, struct spi_device *spi) +{ + dw_spi_enable_chip(dws, 0); + dw_spi_set_cs(spi, true); + dw_spi_enable_chip(dws, 1); +} + +/* + * The SPI memory operation implementation below is the best choice for the + * devices, which are selected by the native chip-select lane. It's + * specifically developed to workaround the problem with automatic chip-select + * lane toggle when there is no data in the Tx FIFO buffer. Luckily the current + * SPI-mem core calls exec_op() callback only if the GPIO-based CS is + * unavailable. + */ +static int dw_spi_exec_mem_op(struct spi_mem *mem, const struct spi_mem_op *op) +{ + struct dw_spi *dws = spi_controller_get_devdata(mem->spi->controller); + struct dw_spi_cfg cfg; + unsigned long flags; + int ret; + + /* + * Collect the outbound data into a single buffer to speed the + * transmission up at least on the initial stage. + */ + ret = dw_spi_init_mem_buf(dws, op); + if (ret) + return ret; + + /* + * DW SPI EEPROM-read mode is required only for the SPI memory Data-IN + * operation. Transmit-only mode is suitable for the rest of them. + */ + cfg.dfs = 8; + cfg.freq = clamp(mem->spi->max_speed_hz, 0U, dws->max_mem_freq); + if (op->data.dir == SPI_MEM_DATA_IN) { + cfg.tmode = DW_SPI_CTRLR0_TMOD_EPROMREAD; + cfg.ndf = op->data.nbytes; + } else { + cfg.tmode = DW_SPI_CTRLR0_TMOD_TO; + } + + dw_spi_enable_chip(dws, 0); + + dw_spi_update_config(dws, mem->spi, &cfg); + + dw_spi_mask_intr(dws, 0xff); + + dw_spi_enable_chip(dws, 1); + + /* + * DW APB SSI controller has very nasty peculiarities. First originally + * (without any vendor-specific modifications) it doesn't provide a + * direct way to set and clear the native chip-select signal. Instead + * the controller asserts the CS lane if Tx FIFO isn't empty and a + * transmission is going on, and automatically de-asserts it back to + * the high level if the Tx FIFO doesn't have anything to be pushed + * out. Due to that a multi-tasking or heavy IRQs activity might be + * fatal, since the transfer procedure preemption may cause the Tx FIFO + * getting empty and sudden CS de-assertion, which in the middle of the + * transfer will most likely cause the data loss. Secondly the + * EEPROM-read or Read-only DW SPI transfer modes imply the incoming + * data being automatically pulled in into the Rx FIFO. So if the + * driver software is late in fetching the data from the FIFO before + * it's overflown, new incoming data will be lost. In order to make + * sure the executed memory operations are CS-atomic and to prevent the + * Rx FIFO overflow we have to disable the local interrupts so to block + * any preemption during the subsequent IO operations. + * + * Note. At some circumstances disabling IRQs may not help to prevent + * the problems described above. The CS de-assertion and Rx FIFO + * overflow may still happen due to the relatively slow system bus or + * CPU not working fast enough, so the write-then-read algo implemented + * here just won't keep up with the SPI bus data transfer. Such + * situation is highly platform specific and is supposed to be fixed by + * manually restricting the SPI bus frequency using the + * dws->max_mem_freq parameter. + */ + local_irq_save(flags); + preempt_disable(); + + ret = dw_spi_write_then_read(dws, mem->spi); + + local_irq_restore(flags); + preempt_enable(); + + /* + * Wait for the operation being finished and check the controller + * status only if there hasn't been any run-time error detected. In the + * former case it's just pointless. In the later one to prevent an + * additional error message printing since any hw error flag being set + * would be due to an error detected on the data transfer. + */ + if (!ret) { + ret = dw_spi_wait_mem_op_done(dws); + if (!ret) + ret = dw_spi_check_status(dws, true); + } + + dw_spi_stop_mem_op(dws, mem->spi); + + dw_spi_free_mem_buf(dws); + + return ret; +} + +/* + * Initialize the default memory operations if a glue layer hasn't specified + * custom ones. Direct mapping operations will be preserved anyway since DW SPI + * controller doesn't have an embedded dirmap interface. Note the memory + * operations implemented in this driver is the best choice only for the DW APB + * SSI controller with standard native CS functionality. If a hardware vendor + * has fixed the automatic CS assertion/de-assertion peculiarity, then it will + * be safer to use the normal SPI-messages-based transfers implementation. + */ +static void dw_spi_init_mem_ops(struct dw_spi *dws) +{ + if (!dws->mem_ops.exec_op && !(dws->caps & DW_SPI_CAP_CS_OVERRIDE) && + !dws->set_cs) { + dws->mem_ops.adjust_op_size = dw_spi_adjust_mem_op_size; + dws->mem_ops.supports_op = dw_spi_supports_mem_op; + dws->mem_ops.exec_op = dw_spi_exec_mem_op; + if (!dws->max_mem_freq) + dws->max_mem_freq = dws->max_freq; + } +} + +/* This may be called twice for each spi dev */ +static int dw_spi_setup(struct spi_device *spi) +{ + struct dw_spi *dws = spi_controller_get_devdata(spi->controller); + struct dw_spi_chip_data *chip; + + /* Only alloc on first setup */ + chip = spi_get_ctldata(spi); + if (!chip) { + struct dw_spi *dws = spi_controller_get_devdata(spi->controller); + u32 rx_sample_dly_ns; + + chip = kzalloc(sizeof(*chip), GFP_KERNEL); + if (!chip) + return -ENOMEM; + spi_set_ctldata(spi, chip); + /* Get specific / default rx-sample-delay */ + if (device_property_read_u32(&spi->dev, + "rx-sample-delay-ns", + &rx_sample_dly_ns) != 0) + /* Use default controller value */ + rx_sample_dly_ns = dws->def_rx_sample_dly_ns; + chip->rx_sample_dly = DIV_ROUND_CLOSEST(rx_sample_dly_ns, + NSEC_PER_SEC / + dws->max_freq); + } + + /* + * Update CR0 data each time the setup callback is invoked since + * the device parameters could have been changed, for instance, by + * the MMC SPI driver or something else. + */ + chip->cr0 = dw_spi_prepare_cr0(dws, spi); + + return 0; +} + +static void dw_spi_cleanup(struct spi_device *spi) +{ + struct dw_spi_chip_data *chip = spi_get_ctldata(spi); + + kfree(chip); + spi_set_ctldata(spi, NULL); +} + +/* Restart the controller, disable all interrupts, clean rx fifo */ +static void dw_spi_hw_init(struct device *dev, struct dw_spi *dws) +{ + dw_spi_reset_chip(dws); + + /* + * Retrieve the Synopsys component version if it hasn't been specified + * by the platform. CoreKit version ID is encoded as a 3-chars ASCII + * code enclosed with '*' (typical for the most of Synopsys IP-cores). + */ + if (!dws->ver) { + dws->ver = dw_readl(dws, DW_SPI_VERSION); + + dev_dbg(dev, "Synopsys DWC%sSSI v%c.%c%c\n", + dw_spi_ip_is(dws, PSSI) ? " APB " : " ", + DW_SPI_GET_BYTE(dws->ver, 3), DW_SPI_GET_BYTE(dws->ver, 2), + DW_SPI_GET_BYTE(dws->ver, 1)); + } + + /* + * Try to detect the FIFO depth if not set by interface driver, + * the depth could be from 2 to 256 from HW spec + */ + if (!dws->fifo_len) { + u32 fifo; + + for (fifo = 1; fifo < 256; fifo++) { + dw_writel(dws, DW_SPI_TXFTLR, fifo); + if (fifo != dw_readl(dws, DW_SPI_TXFTLR)) + break; + } + dw_writel(dws, DW_SPI_TXFTLR, 0); + + dws->fifo_len = (fifo == 1) ? 0 : fifo; + dev_dbg(dev, "Detected FIFO size: %u bytes\n", dws->fifo_len); + } + + /* + * Detect CTRLR0.DFS field size and offset by testing the lowest bits + * writability. Note DWC SSI controller also has the extended DFS, but + * with zero offset. + */ + if (dw_spi_ip_is(dws, PSSI)) { + u32 cr0, tmp = dw_readl(dws, DW_SPI_CTRLR0); + + dw_spi_enable_chip(dws, 0); + dw_writel(dws, DW_SPI_CTRLR0, 0xffffffff); + cr0 = dw_readl(dws, DW_SPI_CTRLR0); + dw_writel(dws, DW_SPI_CTRLR0, tmp); + dw_spi_enable_chip(dws, 1); + + if (!(cr0 & DW_PSSI_CTRLR0_DFS_MASK)) { + dws->caps |= DW_SPI_CAP_DFS32; + dws->dfs_offset = __bf_shf(DW_PSSI_CTRLR0_DFS32_MASK); + dev_dbg(dev, "Detected 32-bits max data frame size\n"); + } + } else { + dws->caps |= DW_SPI_CAP_DFS32; + } + + /* enable HW fixup for explicit CS deselect for Amazon's alpine chip */ + if (dws->caps & DW_SPI_CAP_CS_OVERRIDE) + dw_writel(dws, DW_SPI_CS_OVERRIDE, 0xF); +} + +int dw_spi_add_host(struct device *dev, struct dw_spi *dws) +{ + struct spi_controller *master; + int ret; + + if (!dws) + return -EINVAL; + + master = spi_alloc_master(dev, 0); + if (!master) + return -ENOMEM; + + device_set_node(&master->dev, dev_fwnode(dev)); + + dws->master = master; + dws->dma_addr = (dma_addr_t)(dws->paddr + DW_SPI_DR); + + spi_controller_set_devdata(master, dws); + + /* Basic HW init */ + dw_spi_hw_init(dev, dws); + + ret = request_irq(dws->irq, dw_spi_irq, IRQF_SHARED, dev_name(dev), + master); + if (ret < 0 && ret != -ENOTCONN) { + dev_err(dev, "can not get IRQ\n"); + goto err_free_master; + } + + dw_spi_init_mem_ops(dws); + + master->use_gpio_descriptors = true; + master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP; + if (dws->caps & DW_SPI_CAP_DFS32) + master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 32); + else + master->bits_per_word_mask = SPI_BPW_RANGE_MASK(4, 16); + master->bus_num = dws->bus_num; + master->num_chipselect = dws->num_cs; + master->setup = dw_spi_setup; + master->cleanup = dw_spi_cleanup; + if (dws->set_cs) + master->set_cs = dws->set_cs; + else + master->set_cs = dw_spi_set_cs; + master->transfer_one = dw_spi_transfer_one; + master->handle_err = dw_spi_handle_err; + if (dws->mem_ops.exec_op) + master->mem_ops = &dws->mem_ops; + master->max_speed_hz = dws->max_freq; + master->flags = SPI_MASTER_GPIO_SS; + master->auto_runtime_pm = true; + + /* Get default rx sample delay */ + device_property_read_u32(dev, "rx-sample-delay-ns", + &dws->def_rx_sample_dly_ns); + + if (dws->dma_ops && dws->dma_ops->dma_init) { + ret = dws->dma_ops->dma_init(dev, dws); + if (ret == -EPROBE_DEFER) { + goto err_free_irq; + } else if (ret) { + dev_warn(dev, "DMA init failed\n"); + } else { + master->can_dma = dws->dma_ops->can_dma; + master->flags |= SPI_CONTROLLER_MUST_TX; + } + } + + ret = spi_register_controller(master); + if (ret) { + dev_err_probe(dev, ret, "problem registering spi master\n"); + goto err_dma_exit; + } + + dw_spi_debugfs_init(dws); + return 0; + +err_dma_exit: + if (dws->dma_ops && dws->dma_ops->dma_exit) + dws->dma_ops->dma_exit(dws); + dw_spi_enable_chip(dws, 0); +err_free_irq: + free_irq(dws->irq, master); +err_free_master: + spi_controller_put(master); + return ret; +} +EXPORT_SYMBOL_NS_GPL(dw_spi_add_host, SPI_DW_CORE); + +void dw_spi_remove_host(struct dw_spi *dws) +{ + dw_spi_debugfs_remove(dws); + + spi_unregister_controller(dws->master); + + if (dws->dma_ops && dws->dma_ops->dma_exit) + dws->dma_ops->dma_exit(dws); + + dw_spi_shutdown_chip(dws); + + free_irq(dws->irq, dws->master); +} +EXPORT_SYMBOL_NS_GPL(dw_spi_remove_host, SPI_DW_CORE); + +int dw_spi_suspend_host(struct dw_spi *dws) +{ + int ret; + + ret = spi_controller_suspend(dws->master); + if (ret) + return ret; + + dw_spi_shutdown_chip(dws); + return 0; +} +EXPORT_SYMBOL_NS_GPL(dw_spi_suspend_host, SPI_DW_CORE); + +int dw_spi_resume_host(struct dw_spi *dws) +{ + dw_spi_hw_init(&dws->master->dev, dws); + return spi_controller_resume(dws->master); +} +EXPORT_SYMBOL_NS_GPL(dw_spi_resume_host, SPI_DW_CORE); + +MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>"); +MODULE_DESCRIPTION("Driver for DesignWare SPI controller core"); +MODULE_LICENSE("GPL v2"); |