1 files changed, 545 insertions, 0 deletions
diff --git a/drivers/spi/spi-dw-core.c b/drivers/spi/spi-dw-core.c
new file mode 100644
index 000000000000..323c66c5db50
--- /dev/null
+++ b/drivers/spi/spi-dw-core.c
@@ -0,0 +1,545 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Designware SPI core controller driver (refer pxa2xx_spi.c)
+ *
+ * Copyright (c) 2009, Intel Corporation.
+ */
+
+#include <linux/dma-mapping.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/highmem.h>
+#include <linux/delay.h>
+#include <linux/slab.h>
+#include <linux/spi/spi.h>
+
+#include "spi-dw.h"
+
+#ifdef CONFIG_DEBUG_FS
+#include <linux/debugfs.h>
+#endif
+
+/* Slave spi_dev related */
+struct chip_data {
+	u8 tmode;		/* TR/TO/RO/EEPROM */
+	u8 type;		/* SPI/SSP/MicroWire */
+
+	u16 clk_div;		/* baud rate divider */
+	u32 speed_hz;		/* baud rate */
+};
+
+#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),
+};
+
+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 if (dws->cs_override)
+		dw_writel(dws, DW_SPI_SER, 0);
+}
+EXPORT_SYMBOL_GPL(dw_spi_set_cs);
+
+/* Return the max entries we can fill into tx fifo */
+static inline u32 tx_max(struct dw_spi *dws)
+{
+	u32 tx_left, tx_room, rxtx_gap;
+
+	tx_left = (dws->tx_end - dws->tx) / dws->n_bytes;
+	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->rx_end - dws->rx) - (dws->tx_end - dws->tx))
+			/ dws->n_bytes;
+
+	return min3(tx_left, tx_room, (u32) (dws->fifo_len - rxtx_gap));
+}
+
+/* Return the max entries we should read out of rx fifo */
+static inline u32 rx_max(struct dw_spi *dws)
+{
+	u32 rx_left = (dws->rx_end - dws->rx) / dws->n_bytes;
+
+	return min_t(u32, rx_left, dw_readl(dws, DW_SPI_RXFLR));
+}
+
+static void dw_writer(struct dw_spi *dws)
+{
+	u32 max;
+	u16 txw = 0;
+
+	spin_lock(&dws->buf_lock);
+	max = tx_max(dws);
+	while (max--) {
+		/* Set the tx word if the transfer's original "tx" is not null */
+		if (dws->tx_end - dws->len) {
+			if (dws->n_bytes == 1)
+				txw = *(u8 *)(dws->tx);
+			else
+				txw = *(u16 *)(dws->tx);
+		}
+		dw_write_io_reg(dws, DW_SPI_DR, txw);
+		dws->tx += dws->n_bytes;
+	}
+	spin_unlock(&dws->buf_lock);
+}
+
+static void dw_reader(struct dw_spi *dws)
+{
+	u32 max;
+	u16 rxw;
+
+	spin_lock(&dws->buf_lock);
+	max = rx_max(dws);
+	while (max--) {
+		rxw = dw_read_io_reg(dws, DW_SPI_DR);
+		/* Care rx only if the transfer's original "rx" is not null */
+		if (dws->rx_end - dws->len) {
+			if (dws->n_bytes == 1)
+				*(u8 *)(dws->rx) = rxw;
+			else
+				*(u16 *)(dws->rx) = rxw;
+		}
+		dws->rx += dws->n_bytes;
+	}
+	spin_unlock(&dws->buf_lock);
+}
+
+static void int_error_stop(struct dw_spi *dws, const char *msg)
+{
+	spi_reset_chip(dws);
+
+	dev_err(&dws->master->dev, "%s\n", msg);
+	dws->master->cur_msg->status = -EIO;
+	spi_finalize_current_transfer(dws->master);
+}
+
+static irqreturn_t interrupt_transfer(struct dw_spi *dws)
+{
+	u16 irq_status = dw_readl(dws, DW_SPI_ISR);
+
+	/* Error handling */
+	if (irq_status & (SPI_INT_TXOI | SPI_INT_RXOI | SPI_INT_RXUI)) {
+		dw_readl(dws, DW_SPI_ICR);
+		int_error_stop(dws, "interrupt_transfer: fifo overrun/underrun");
+		return IRQ_HANDLED;
+	}
+
+	dw_reader(dws);
+	if (dws->rx_end == dws->rx) {
+		spi_mask_intr(dws, SPI_INT_TXEI);
+		spi_finalize_current_transfer(dws->master);
+		return IRQ_HANDLED;
+	}
+	if (irq_status & SPI_INT_TXEI) {
+		spi_mask_intr(dws, SPI_INT_TXEI);
+		dw_writer(dws);
+		/* Enable TX irq always, it will be disabled when RX finished */
+		spi_umask_intr(dws, 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) & 0x3f;
+
+	if (!irq_status)
+		return IRQ_NONE;
+
+	if (!master->cur_msg) {
+		spi_mask_intr(dws, SPI_INT_TXEI);
+		return IRQ_HANDLED;
+	}
+
+	return dws->transfer_handler(dws);
+}
+
+/* Configure CTRLR0 for DW_apb_ssi */
+u32 dw_spi_update_cr0(struct spi_controller *master, struct spi_device *spi,
+		      struct spi_transfer *transfer)
+{
+	struct chip_data *chip = spi_get_ctldata(spi);
+	u32 cr0;
+
+	/* Default SPI mode is SCPOL = 0, SCPH = 0 */
+	cr0 = (transfer->bits_per_word - 1)
+		| (chip->type << SPI_FRF_OFFSET)
+		| ((((spi->mode & SPI_CPOL) ? 1 : 0) << SPI_SCOL_OFFSET) |
+		   (((spi->mode & SPI_CPHA) ? 1 : 0) << SPI_SCPH_OFFSET) |
+		   (((spi->mode & SPI_LOOP) ? 1 : 0) << SPI_SRL_OFFSET))
+		| (chip->tmode << SPI_TMOD_OFFSET);
+
+	return cr0;
+}
+EXPORT_SYMBOL_GPL(dw_spi_update_cr0);
+
+/* Configure CTRLR0 for DWC_ssi */
+u32 dw_spi_update_cr0_v1_01a(struct spi_controller *master,
+			     struct spi_device *spi,
+			     struct spi_transfer *transfer)
+{
+	struct chip_data *chip = spi_get_ctldata(spi);
+	u32 cr0;
+
+	/* CTRLR0[ 4: 0] Data Frame Size */
+	cr0 = (transfer->bits_per_word - 1);
+
+	/* CTRLR0[ 7: 6] Frame Format */
+	cr0 |= chip->type << DWC_SSI_CTRLR0_FRF_OFFSET;
+
+	/*
+	 * SPI mode (SCPOL|SCPH)
+	 * CTRLR0[ 8] Serial Clock Phase
+	 * CTRLR0[ 9] Serial Clock Polarity
+	 */
+	cr0 |= ((spi->mode & SPI_CPOL) ? 1 : 0) << DWC_SSI_CTRLR0_SCPOL_OFFSET;
+	cr0 |= ((spi->mode & SPI_CPHA) ? 1 : 0) << DWC_SSI_CTRLR0_SCPH_OFFSET;
+
+	/* CTRLR0[11:10] Transfer Mode */
+	cr0 |= chip->tmode << DWC_SSI_CTRLR0_TMOD_OFFSET;
+
+	/* CTRLR0[13] Shift Register Loop */
+	cr0 |= ((spi->mode & SPI_LOOP) ? 1 : 0) << DWC_SSI_CTRLR0_SRL_OFFSET;
+
+	return cr0;
+}
+EXPORT_SYMBOL_GPL(dw_spi_update_cr0_v1_01a);
+
+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 chip_data *chip = spi_get_ctldata(spi);
+	unsigned long flags;
+	u8 imask = 0;
+	u16 txlevel = 0;
+	u32 cr0;
+	int ret;
+
+	dws->dma_mapped = 0;
+	spin_lock_irqsave(&dws->buf_lock, flags);
+	dws->tx = (void *)transfer->tx_buf;
+	dws->tx_end = dws->tx + transfer->len;
+	dws->rx = transfer->rx_buf;
+	dws->rx_end = dws->rx + transfer->len;
+	dws->len = transfer->len;
+	spin_unlock_irqrestore(&dws->buf_lock, flags);
+
+	/* Ensure dw->rx and dw->rx_end are visible */
+	smp_mb();
+
+	spi_enable_chip(dws, 0);
+
+	/* Handle per transfer options for bpw and speed */
+	if (transfer->speed_hz != dws->current_freq) {
+		if (transfer->speed_hz != chip->speed_hz) {
+			/* clk_div doesn't support odd number */
+			chip->clk_div = (DIV_ROUND_UP(dws->max_freq, transfer->speed_hz) + 1) & 0xfffe;
+			chip->speed_hz = transfer->speed_hz;
+		}
+		dws->current_freq = transfer->speed_hz;
+		spi_set_clk(dws, chip->clk_div);
+	}
+
+	transfer->effective_speed_hz = dws->max_freq / chip->clk_div;
+	dws->n_bytes = DIV_ROUND_UP(transfer->bits_per_word, BITS_PER_BYTE);
+
+	cr0 = dws->update_cr0(master, spi, transfer);
+	dw_writel(dws, DW_SPI_CTRLR0, cr0);
+
+	/* 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 */
+	spi_mask_intr(dws, 0xff);
+
+	/*
+	 * Interrupt mode
+	 * we only need set the TXEI IRQ, as TX/RX always happen syncronizely
+	 */
+	if (dws->dma_mapped) {
+		ret = dws->dma_ops->dma_setup(dws, transfer);
+		if (ret < 0) {
+			spi_enable_chip(dws, 1);
+			return ret;
+		}
+	} else {
+		txlevel = min_t(u16, dws->fifo_len / 2, dws->len / dws->n_bytes);
+		dw_writel(dws, DW_SPI_TXFTLR, txlevel);
+
+		/* Set the interrupt mask */
+		imask |= SPI_INT_TXEI | SPI_INT_TXOI |
+			 SPI_INT_RXUI | SPI_INT_RXOI;
+		spi_umask_intr(dws, imask);
+
+		dws->transfer_handler = interrupt_transfer;
+	}
+
+	spi_enable_chip(dws, 1);
+
+	if (dws->dma_mapped)
+		return dws->dma_ops->dma_transfer(dws, transfer);
+
+	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);
+
+	spi_reset_chip(dws);
+}
+
+/* This may be called twice for each spi dev */
+static int dw_spi_setup(struct spi_device *spi)
+{
+	struct chip_data *chip;
+
+	/* Only alloc on first setup */
+	chip = spi_get_ctldata(spi);
+	if (!chip) {
+		chip = kzalloc(sizeof(struct chip_data), GFP_KERNEL);
+		if (!chip)
+			return -ENOMEM;
+		spi_set_ctldata(spi, chip);
+	}
+
+	chip->tmode = SPI_TMOD_TR;
+
+	return 0;
+}
+
+static void dw_spi_cleanup(struct spi_device *spi)
+{
+	struct 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 spi_hw_init(struct device *dev, struct dw_spi *dws)
+{
+	spi_reset_chip(dws);
+
+	/*
+	 * 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);
+	}
+
+	/* enable HW fixup for explicit CS deselect for Amazon's alpine chip */
+	if (dws->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;
+
+	dws->master = master;
+	dws->type = SSI_MOTO_SPI;
+	dws->dma_addr = (dma_addr_t)(dws->paddr + DW_SPI_DR);
+	spin_lock_init(&dws->buf_lock);
+
+	spi_controller_set_devdata(master, dws);
+
+	ret = request_irq(dws->irq, dw_spi_irq, IRQF_SHARED, dev_name(dev),
+			  master);
+	if (ret < 0) {
+		dev_err(dev, "can not get IRQ\n");
+		goto err_free_master;
+	}
+
+	master->use_gpio_descriptors = true;
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LOOP;
+	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;
+	master->set_cs = dw_spi_set_cs;
+	master->transfer_one = dw_spi_transfer_one;
+	master->handle_err = dw_spi_handle_err;
+	master->max_speed_hz = dws->max_freq;
+	master->dev.of_node = dev->of_node;
+	master->dev.fwnode = dev->fwnode;
+	master->flags = SPI_MASTER_GPIO_SS;
+	master->auto_runtime_pm = true;
+
+	if (dws->set_cs)
+		master->set_cs = dws->set_cs;
+
+	/* Basic HW init */
+	spi_hw_init(dev, dws);
+
+	if (dws->dma_ops && dws->dma_ops->dma_init) {
+		ret = dws->dma_ops->dma_init(dev, dws);
+		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(&master->dev, "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);
+	spi_enable_chip(dws, 0);
+	free_irq(dws->irq, master);
+err_free_master:
+	spi_controller_put(master);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(dw_spi_add_host);
+
+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);
+
+	spi_shutdown_chip(dws);
+
+	free_irq(dws->irq, dws->master);
+}
+EXPORT_SYMBOL_GPL(dw_spi_remove_host);
+
+int dw_spi_suspend_host(struct dw_spi *dws)
+{
+	int ret;
+
+	ret = spi_controller_suspend(dws->master);
+	if (ret)
+		return ret;
+
+	spi_shutdown_chip(dws);
+	return 0;
+}
+EXPORT_SYMBOL_GPL(dw_spi_suspend_host);
+
+int dw_spi_resume_host(struct dw_spi *dws)
+{
+	spi_hw_init(&dws->master->dev, dws);
+	return spi_controller_resume(dws->master);
+}
+EXPORT_SYMBOL_GPL(dw_spi_resume_host);
+
+MODULE_AUTHOR("Feng Tang <feng.tang@intel.com>");
+MODULE_DESCRIPTION("Driver for DesignWare SPI controller core");
+MODULE_LICENSE("GPL v2");