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-rw-r--r--drivers/spi/spi-dw-core.c1017
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");