1 files changed, 838 insertions, 0 deletions

diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
new file mode 100644
index 00000000000..3579b7d7db5
--- /dev/null
+++ b/drivers/spi/spi-mem.c
@@ -0,0 +1,838 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Exceet Electronics GmbH
+ * Copyright (C) 2018 Bootlin
+ *
+ * Author: Boris Brezillon <boris.brezillon@bootlin.com>
+ */
+
+#ifndef __UBOOT__
+#include <log.h>
+#include <dm/devres.h>
+#include <linux/dmaengine.h>
+#include <linux/pm_runtime.h>
+#include "internals.h"
+#else
+#include <dm.h>
+#include <errno.h>
+#include <malloc.h>
+#include <spi.h>
+#include <spi.h>
+#include <spi-mem.h>
+#include <dm/device_compat.h>
+#include <dm/devres.h>
+#include <linux/bug.h>
+#endif
+
+#ifndef __UBOOT__
+/**
+ * spi_controller_dma_map_mem_op_data() - DMA-map the buffer attached to a
+ *					  memory operation
+ * @ctlr: the SPI controller requesting this dma_map()
+ * @op: the memory operation containing the buffer to map
+ * @sgt: a pointer to a non-initialized sg_table that will be filled by this
+ *	 function
+ *
+ * Some controllers might want to do DMA on the data buffer embedded in @op.
+ * This helper prepares everything for you and provides a ready-to-use
+ * sg_table. This function is not intended to be called from spi drivers.
+ * Only SPI controller drivers should use it.
+ * Note that the caller must ensure the memory region pointed by
+ * op->data.buf.{in,out} is DMA-able before calling this function.
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+int spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
+				       const struct spi_mem_op *op,
+				       struct sg_table *sgt)
+{
+	struct device *dmadev;
+
+	if (!op->data.nbytes)
+		return -EINVAL;
+
+	if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
+		dmadev = ctlr->dma_tx->device->dev;
+	else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
+		dmadev = ctlr->dma_rx->device->dev;
+	else
+		dmadev = ctlr->dev.parent;
+
+	if (!dmadev)
+		return -EINVAL;
+
+	return spi_map_buf(ctlr, dmadev, sgt, op->data.buf.in, op->data.nbytes,
+			   op->data.dir == SPI_MEM_DATA_IN ?
+			   DMA_FROM_DEVICE : DMA_TO_DEVICE);
+}
+EXPORT_SYMBOL_GPL(spi_controller_dma_map_mem_op_data);
+
+/**
+ * spi_controller_dma_unmap_mem_op_data() - DMA-unmap the buffer attached to a
+ *					    memory operation
+ * @ctlr: the SPI controller requesting this dma_unmap()
+ * @op: the memory operation containing the buffer to unmap
+ * @sgt: a pointer to an sg_table previously initialized by
+ *	 spi_controller_dma_map_mem_op_data()
+ *
+ * Some controllers might want to do DMA on the data buffer embedded in @op.
+ * This helper prepares things so that the CPU can access the
+ * op->data.buf.{in,out} buffer again.
+ *
+ * This function is not intended to be called from SPI drivers. Only SPI
+ * controller drivers should use it.
+ *
+ * This function should be called after the DMA operation has finished and is
+ * only valid if the previous spi_controller_dma_map_mem_op_data() call
+ * returned 0.
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
+					  const struct spi_mem_op *op,
+					  struct sg_table *sgt)
+{
+	struct device *dmadev;
+
+	if (!op->data.nbytes)
+		return;
+
+	if (op->data.dir == SPI_MEM_DATA_OUT && ctlr->dma_tx)
+		dmadev = ctlr->dma_tx->device->dev;
+	else if (op->data.dir == SPI_MEM_DATA_IN && ctlr->dma_rx)
+		dmadev = ctlr->dma_rx->device->dev;
+	else
+		dmadev = ctlr->dev.parent;
+
+	spi_unmap_buf(ctlr, dmadev, sgt,
+		      op->data.dir == SPI_MEM_DATA_IN ?
+		      DMA_FROM_DEVICE : DMA_TO_DEVICE);
+}
+EXPORT_SYMBOL_GPL(spi_controller_dma_unmap_mem_op_data);
+#endif /* __UBOOT__ */
+
+static int spi_check_buswidth_req(struct spi_slave *slave, u8 buswidth, bool tx)
+{
+	u32 mode = slave->mode;
+
+	switch (buswidth) {
+	case 1:
+		return 0;
+
+	case 2:
+		if ((tx && (mode & (SPI_TX_DUAL | SPI_TX_QUAD))) ||
+		    (!tx && (mode & (SPI_RX_DUAL | SPI_RX_QUAD))))
+			return 0;
+
+		break;
+
+	case 4:
+		if ((tx && (mode & SPI_TX_QUAD)) ||
+		    (!tx && (mode & SPI_RX_QUAD)))
+			return 0;
+
+		break;
+	case 8:
+		if ((tx && (mode & SPI_TX_OCTAL)) ||
+		    (!tx && (mode & SPI_RX_OCTAL)))
+			return 0;
+
+		break;
+
+	default:
+		break;
+	}
+
+	return -ENOTSUPP;
+}
+
+static bool spi_mem_check_buswidth(struct spi_slave *slave,
+				   const struct spi_mem_op *op)
+{
+	if (spi_check_buswidth_req(slave, op->cmd.buswidth, true))
+		return false;
+
+	if (op->addr.nbytes &&
+	    spi_check_buswidth_req(slave, op->addr.buswidth, true))
+		return false;
+
+	if (op->dummy.nbytes &&
+	    spi_check_buswidth_req(slave, op->dummy.buswidth, true))
+		return false;
+
+	if (op->data.dir != SPI_MEM_NO_DATA &&
+	    spi_check_buswidth_req(slave, op->data.buswidth,
+				   op->data.dir == SPI_MEM_DATA_OUT))
+		return false;
+
+	return true;
+}
+
+bool spi_mem_dtr_supports_op(struct spi_slave *slave,
+			     const struct spi_mem_op *op)
+{
+	if (op->cmd.buswidth == 8 && op->cmd.nbytes % 2)
+		return false;
+
+	if (op->addr.nbytes && op->addr.buswidth == 8 && op->addr.nbytes % 2)
+		return false;
+
+	if (op->dummy.nbytes && op->dummy.buswidth == 8 && op->dummy.nbytes % 2)
+		return false;
+
+	/*
+	 * Transactions of odd length do not make sense for 8D-8D-8D mode
+	 * because a byte is transferred in just half a cycle.
+	 */
+	if (op->data.dir != SPI_MEM_NO_DATA && op->data.dir != SPI_MEM_DATA_IN &&
+	    op->data.buswidth == 8 && op->data.nbytes % 2)
+		return false;
+
+	return spi_mem_check_buswidth(slave, op);
+}
+EXPORT_SYMBOL_GPL(spi_mem_dtr_supports_op);
+
+bool spi_mem_default_supports_op(struct spi_slave *slave,
+				 const struct spi_mem_op *op)
+{
+	if (op->cmd.dtr || op->addr.dtr || op->dummy.dtr || op->data.dtr)
+		return false;
+
+	if (op->cmd.nbytes != 1)
+		return false;
+
+	return spi_mem_check_buswidth(slave, op);
+}
+EXPORT_SYMBOL_GPL(spi_mem_default_supports_op);
+
+/**
+ * spi_mem_supports_op() - Check if a memory device and the controller it is
+ *			   connected to support a specific memory operation
+ * @slave: the SPI device
+ * @op: the memory operation to check
+ *
+ * Some controllers are only supporting Single or Dual IOs, others might only
+ * support specific opcodes, or it can even be that the controller and device
+ * both support Quad IOs but the hardware prevents you from using it because
+ * only 2 IO lines are connected.
+ *
+ * This function checks whether a specific operation is supported.
+ *
+ * Return: true if @op is supported, false otherwise.
+ */
+bool spi_mem_supports_op(struct spi_slave *slave,
+			 const struct spi_mem_op *op)
+{
+	struct udevice *bus = slave->dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+
+	if (ops->mem_ops && ops->mem_ops->supports_op)
+		return ops->mem_ops->supports_op(slave, op);
+
+	return spi_mem_default_supports_op(slave, op);
+}
+EXPORT_SYMBOL_GPL(spi_mem_supports_op);
+
+/**
+ * spi_mem_exec_op() - Execute a memory operation
+ * @slave: the SPI device
+ * @op: the memory operation to execute
+ *
+ * Executes a memory operation.
+ *
+ * This function first checks that @op is supported and then tries to execute
+ * it.
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+int spi_mem_exec_op(struct spi_slave *slave, const struct spi_mem_op *op)
+{
+	struct udevice *bus = slave->dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+	unsigned int pos = 0;
+	const u8 *tx_buf = NULL;
+	u8 *rx_buf = NULL;
+	int op_len;
+	u32 flag;
+	int ret;
+	int i;
+
+	if (!spi_mem_supports_op(slave, op))
+		return -ENOTSUPP;
+
+	ret = spi_claim_bus(slave);
+	if (ret < 0)
+		return ret;
+
+	if (ops->mem_ops && ops->mem_ops->exec_op) {
+#ifndef __UBOOT__
+		/*
+		 * Flush the message queue before executing our SPI memory
+		 * operation to prevent preemption of regular SPI transfers.
+		 */
+		spi_flush_queue(ctlr);
+
+		if (ctlr->auto_runtime_pm) {
+			ret = pm_runtime_get_sync(ctlr->dev.parent);
+			if (ret < 0) {
+				dev_err(&ctlr->dev,
+					"Failed to power device: %d\n",
+					ret);
+				return ret;
+			}
+		}
+
+		mutex_lock(&ctlr->bus_lock_mutex);
+		mutex_lock(&ctlr->io_mutex);
+#endif
+		ret = ops->mem_ops->exec_op(slave, op);
+
+#ifndef __UBOOT__
+		mutex_unlock(&ctlr->io_mutex);
+		mutex_unlock(&ctlr->bus_lock_mutex);
+
+		if (ctlr->auto_runtime_pm)
+			pm_runtime_put(ctlr->dev.parent);
+#endif
+
+		/*
+		 * Some controllers only optimize specific paths (typically the
+		 * read path) and expect the core to use the regular SPI
+		 * interface in other cases.
+		 */
+		if (!ret || ret != -ENOTSUPP) {
+			spi_release_bus(slave);
+			return ret;
+		}
+	}
+
+#ifndef __UBOOT__
+	tmpbufsize = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
+
+	/*
+	 * Allocate a buffer to transmit the CMD, ADDR cycles with kmalloc() so
+	 * we're guaranteed that this buffer is DMA-able, as required by the
+	 * SPI layer.
+	 */
+	tmpbuf = kzalloc(tmpbufsize, GFP_KERNEL | GFP_DMA);
+	if (!tmpbuf)
+		return -ENOMEM;
+
+	spi_message_init(&msg);
+
+	tmpbuf[0] = op->cmd.opcode;
+	xfers[xferpos].tx_buf = tmpbuf;
+	xfers[xferpos].len = op->cmd.nbytes;
+	xfers[xferpos].tx_nbits = op->cmd.buswidth;
+	spi_message_add_tail(&xfers[xferpos], &msg);
+	xferpos++;
+	totalxferlen++;
+
+	if (op->addr.nbytes) {
+		int i;
+
+		for (i = 0; i < op->addr.nbytes; i++)
+			tmpbuf[i + 1] = op->addr.val >>
+					(8 * (op->addr.nbytes - i - 1));
+
+		xfers[xferpos].tx_buf = tmpbuf + 1;
+		xfers[xferpos].len = op->addr.nbytes;
+		xfers[xferpos].tx_nbits = op->addr.buswidth;
+		spi_message_add_tail(&xfers[xferpos], &msg);
+		xferpos++;
+		totalxferlen += op->addr.nbytes;
+	}
+
+	if (op->dummy.nbytes) {
+		memset(tmpbuf + op->addr.nbytes + 1, 0xff, op->dummy.nbytes);
+		xfers[xferpos].tx_buf = tmpbuf + op->addr.nbytes + 1;
+		xfers[xferpos].len = op->dummy.nbytes;
+		xfers[xferpos].tx_nbits = op->dummy.buswidth;
+		spi_message_add_tail(&xfers[xferpos], &msg);
+		xferpos++;
+		totalxferlen += op->dummy.nbytes;
+	}
+
+	if (op->data.nbytes) {
+		if (op->data.dir == SPI_MEM_DATA_IN) {
+			xfers[xferpos].rx_buf = op->data.buf.in;
+			xfers[xferpos].rx_nbits = op->data.buswidth;
+		} else {
+			xfers[xferpos].tx_buf = op->data.buf.out;
+			xfers[xferpos].tx_nbits = op->data.buswidth;
+		}
+
+		xfers[xferpos].len = op->data.nbytes;
+		spi_message_add_tail(&xfers[xferpos], &msg);
+		xferpos++;
+		totalxferlen += op->data.nbytes;
+	}
+
+	ret = spi_sync(slave, &msg);
+
+	kfree(tmpbuf);
+
+	if (ret)
+		return ret;
+
+	if (msg.actual_length != totalxferlen)
+		return -EIO;
+#else
+
+	if (op->data.nbytes) {
+		if (op->data.dir == SPI_MEM_DATA_IN)
+			rx_buf = op->data.buf.in;
+		else
+			tx_buf = op->data.buf.out;
+	}
+
+	op_len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
+
+	/*
+	 * Avoid using malloc() here so that we can use this code in SPL where
+	 * simple malloc may be used. That implementation does not allow free()
+	 * so repeated calls to this code can exhaust the space.
+	 *
+	 * The value of op_len is small, since it does not include the actual
+	 * data being sent, only the op-code and address. In fact, it should be
+	 * possible to just use a small fixed value here instead of op_len.
+	 */
+	u8 op_buf[op_len];
+
+	op_buf[pos++] = op->cmd.opcode;
+
+	if (op->addr.nbytes) {
+		for (i = 0; i < op->addr.nbytes; i++)
+			op_buf[pos + i] = op->addr.val >>
+				(8 * (op->addr.nbytes - i - 1));
+
+		pos += op->addr.nbytes;
+	}
+
+	if (op->dummy.nbytes)
+		memset(op_buf + pos, 0xff, op->dummy.nbytes);
+
+	/* 1st transfer: opcode + address + dummy cycles */
+	flag = SPI_XFER_BEGIN;
+	/* Make sure to set END bit if no tx or rx data messages follow */
+	if (!tx_buf && !rx_buf)
+		flag |= SPI_XFER_END;
+
+	ret = spi_xfer(slave, op_len * 8, op_buf, NULL, flag);
+	if (ret)
+		return ret;
+
+	/* 2nd transfer: rx or tx data path */
+	if (tx_buf || rx_buf) {
+		ret = spi_xfer(slave, op->data.nbytes * 8, tx_buf,
+			       rx_buf, SPI_XFER_END);
+		if (ret)
+			return ret;
+	}
+
+	spi_release_bus(slave);
+
+	for (i = 0; i < pos; i++)
+		debug("%02x ", op_buf[i]);
+	debug("| [%dB %s] ",
+	      tx_buf || rx_buf ? op->data.nbytes : 0,
+	      tx_buf || rx_buf ? (tx_buf ? "out" : "in") : "-");
+	for (i = 0; i < op->data.nbytes; i++)
+		debug("%02x ", tx_buf ? tx_buf[i] : rx_buf[i]);
+	debug("[ret %d]\n", ret);
+
+	if (ret < 0)
+		return ret;
+#endif /* __UBOOT__ */
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(spi_mem_exec_op);
+
+/**
+ * spi_mem_adjust_op_size() - Adjust the data size of a SPI mem operation to
+ *				 match controller limitations
+ * @slave: the SPI device
+ * @op: the operation to adjust
+ *
+ * Some controllers have FIFO limitations and must split a data transfer
+ * operation into multiple ones, others require a specific alignment for
+ * optimized accesses. This function allows SPI mem drivers to split a single
+ * operation into multiple sub-operations when required.
+ *
+ * Return: a negative error code if the controller can't properly adjust @op,
+ *	   0 otherwise. Note that @op->data.nbytes will be updated if @op
+ *	   can't be handled in a single step.
+ */
+int spi_mem_adjust_op_size(struct spi_slave *slave, struct spi_mem_op *op)
+{
+	struct udevice *bus = slave->dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+
+	if (ops->mem_ops && ops->mem_ops->adjust_op_size)
+		return ops->mem_ops->adjust_op_size(slave, op);
+
+	if (!ops->mem_ops || !ops->mem_ops->exec_op) {
+		unsigned int len;
+
+		len = op->cmd.nbytes + op->addr.nbytes + op->dummy.nbytes;
+		if (slave->max_write_size && len > slave->max_write_size)
+			return -EINVAL;
+
+		if (op->data.dir == SPI_MEM_DATA_IN) {
+			if (slave->max_read_size)
+				op->data.nbytes = min(op->data.nbytes,
+					      slave->max_read_size);
+		} else if (slave->max_write_size) {
+			op->data.nbytes = min(op->data.nbytes,
+					      slave->max_write_size - len);
+		}
+
+		if (!op->data.nbytes)
+			return -EINVAL;
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);
+
+static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc,
+				      u64 offs, size_t len, void *buf)
+{
+	struct spi_mem_op op = desc->info.op_tmpl;
+	int ret;
+
+	op.addr.val = desc->info.offset + offs;
+	op.data.buf.in = buf;
+	op.data.nbytes = len;
+	ret = spi_mem_adjust_op_size(desc->slave, &op);
+	if (ret)
+		return ret;
+
+	ret = spi_mem_exec_op(desc->slave, &op);
+	if (ret)
+		return ret;
+
+	return op.data.nbytes;
+}
+
+static ssize_t spi_mem_no_dirmap_write(struct spi_mem_dirmap_desc *desc,
+				       u64 offs, size_t len, const void *buf)
+{
+	struct spi_mem_op op = desc->info.op_tmpl;
+	int ret;
+
+	op.addr.val = desc->info.offset + offs;
+	op.data.buf.out = buf;
+	op.data.nbytes = len;
+	ret = spi_mem_adjust_op_size(desc->slave, &op);
+	if (ret)
+		return ret;
+
+	ret = spi_mem_exec_op(desc->slave, &op);
+	if (ret)
+		return ret;
+
+	return op.data.nbytes;
+}
+
+/**
+ * spi_mem_dirmap_create() - Create a direct mapping descriptor
+ * @mem: SPI mem device this direct mapping should be created for
+ * @info: direct mapping information
+ *
+ * This function is creating a direct mapping descriptor which can then be used
+ * to access the memory using spi_mem_dirmap_read() or spi_mem_dirmap_write().
+ * If the SPI controller driver does not support direct mapping, this function
+ * falls back to an implementation using spi_mem_exec_op(), so that the caller
+ * doesn't have to bother implementing a fallback on his own.
+ *
+ * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
+ */
+struct spi_mem_dirmap_desc *
+spi_mem_dirmap_create(struct spi_slave *slave,
+		      const struct spi_mem_dirmap_info *info)
+{
+	struct udevice *bus = slave->dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+	struct spi_mem_dirmap_desc *desc;
+	int ret = -EOPNOTSUPP;
+
+	/* Make sure the number of address cycles is between 1 and 8 bytes. */
+	if (!info->op_tmpl.addr.nbytes || info->op_tmpl.addr.nbytes > 8)
+		return ERR_PTR(-EINVAL);
+
+	/* data.dir should either be SPI_MEM_DATA_IN or SPI_MEM_DATA_OUT. */
+	if (info->op_tmpl.data.dir == SPI_MEM_NO_DATA)
+		return ERR_PTR(-EINVAL);
+
+	desc = kzalloc(sizeof(*desc), GFP_KERNEL);
+	if (!desc)
+		return ERR_PTR(-ENOMEM);
+
+	desc->slave = slave;
+	desc->info = *info;
+	if (ops->mem_ops && ops->mem_ops->dirmap_create)
+		ret = ops->mem_ops->dirmap_create(desc);
+
+	if (ret) {
+		desc->nodirmap = true;
+		if (!spi_mem_supports_op(desc->slave, &desc->info.op_tmpl))
+			ret = -EOPNOTSUPP;
+		else
+			ret = 0;
+	}
+
+	if (ret) {
+		kfree(desc);
+		return ERR_PTR(ret);
+	}
+
+	return desc;
+}
+EXPORT_SYMBOL_GPL(spi_mem_dirmap_create);
+
+/**
+ * spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor
+ * @desc: the direct mapping descriptor to destroy
+ *
+ * This function destroys a direct mapping descriptor previously created by
+ * spi_mem_dirmap_create().
+ */
+void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc)
+{
+	struct udevice *bus = desc->slave->dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+
+	if (!desc->nodirmap && ops->mem_ops && ops->mem_ops->dirmap_destroy)
+		ops->mem_ops->dirmap_destroy(desc);
+
+	kfree(desc);
+}
+EXPORT_SYMBOL_GPL(spi_mem_dirmap_destroy);
+
+#ifndef __UBOOT__
+static void devm_spi_mem_dirmap_release(struct udevice *dev, void *res)
+{
+	struct spi_mem_dirmap_desc *desc = *(struct spi_mem_dirmap_desc **)res;
+
+	spi_mem_dirmap_destroy(desc);
+}
+
+/**
+ * devm_spi_mem_dirmap_create() - Create a direct mapping descriptor and attach
+ *				  it to a device
+ * @dev: device the dirmap desc will be attached to
+ * @mem: SPI mem device this direct mapping should be created for
+ * @info: direct mapping information
+ *
+ * devm_ variant of the spi_mem_dirmap_create() function. See
+ * spi_mem_dirmap_create() for more details.
+ *
+ * Return: a valid pointer in case of success, and ERR_PTR() otherwise.
+ */
+struct spi_mem_dirmap_desc *
+devm_spi_mem_dirmap_create(struct udevice *dev, struct spi_slave *slave,
+			   const struct spi_mem_dirmap_info *info)
+{
+	struct spi_mem_dirmap_desc **ptr, *desc;
+
+	ptr = devres_alloc(devm_spi_mem_dirmap_release, sizeof(*ptr),
+			   GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	desc = spi_mem_dirmap_create(slave, info);
+	if (IS_ERR(desc)) {
+		devres_free(ptr);
+	} else {
+		*ptr = desc;
+		devres_add(dev, ptr);
+	}
+
+	return desc;
+}
+EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_create);
+
+static int devm_spi_mem_dirmap_match(struct udevice *dev, void *res, void *data)
+{
+	struct spi_mem_dirmap_desc **ptr = res;
+
+	if (WARN_ON(!ptr || !*ptr))
+		return 0;
+
+	return *ptr == data;
+}
+
+/**
+ * devm_spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor attached
+ *				   to a device
+ * @dev: device the dirmap desc is attached to
+ * @desc: the direct mapping descriptor to destroy
+ *
+ * devm_ variant of the spi_mem_dirmap_destroy() function. See
+ * spi_mem_dirmap_destroy() for more details.
+ */
+void devm_spi_mem_dirmap_destroy(struct udevice *dev,
+				 struct spi_mem_dirmap_desc *desc)
+{
+	devres_release(dev, devm_spi_mem_dirmap_release,
+		       devm_spi_mem_dirmap_match, desc);
+}
+EXPORT_SYMBOL_GPL(devm_spi_mem_dirmap_destroy);
+#endif /* __UBOOT__ */
+
+/**
+ * spi_mem_dirmap_read() - Read data through a direct mapping
+ * @desc: direct mapping descriptor
+ * @offs: offset to start reading from. Note that this is not an absolute
+ *	  offset, but the offset within the direct mapping which already has
+ *	  its own offset
+ * @len: length in bytes
+ * @buf: destination buffer. This buffer must be DMA-able
+ *
+ * This function reads data from a memory device using a direct mapping
+ * previously instantiated with spi_mem_dirmap_create().
+ *
+ * Return: the amount of data read from the memory device or a negative error
+ * code. Note that the returned size might be smaller than @len, and the caller
+ * is responsible for calling spi_mem_dirmap_read() again when that happens.
+ */
+ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc,
+			    u64 offs, size_t len, void *buf)
+{
+	struct udevice *bus = desc->slave->dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+	ssize_t ret;
+
+	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN)
+		return -EINVAL;
+
+	if (!len)
+		return 0;
+
+	if (desc->nodirmap)
+		ret = spi_mem_no_dirmap_read(desc, offs, len, buf);
+	else if (ops->mem_ops && ops->mem_ops->dirmap_read)
+		ret = ops->mem_ops->dirmap_read(desc, offs, len, buf);
+	else
+		ret = -EOPNOTSUPP;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(spi_mem_dirmap_read);
+
+/**
+ * spi_mem_dirmap_write() - Write data through a direct mapping
+ * @desc: direct mapping descriptor
+ * @offs: offset to start writing from. Note that this is not an absolute
+ *	  offset, but the offset within the direct mapping which already has
+ *	  its own offset
+ * @len: length in bytes
+ * @buf: source buffer. This buffer must be DMA-able
+ *
+ * This function writes data to a memory device using a direct mapping
+ * previously instantiated with spi_mem_dirmap_create().
+ *
+ * Return: the amount of data written to the memory device or a negative error
+ * code. Note that the returned size might be smaller than @len, and the caller
+ * is responsible for calling spi_mem_dirmap_write() again when that happens.
+ */
+ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc,
+			     u64 offs, size_t len, const void *buf)
+{
+	struct udevice *bus = desc->slave->dev->parent;
+	struct dm_spi_ops *ops = spi_get_ops(bus);
+	ssize_t ret;
+
+	if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_OUT)
+		return -EINVAL;
+
+	if (!len)
+		return 0;
+
+	if (desc->nodirmap)
+		ret = spi_mem_no_dirmap_write(desc, offs, len, buf);
+	else if (ops->mem_ops && ops->mem_ops->dirmap_write)
+		ret = ops->mem_ops->dirmap_write(desc, offs, len, buf);
+	else
+		ret = -EOPNOTSUPP;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(spi_mem_dirmap_write);
+
+#ifndef __UBOOT__
+static inline struct spi_mem_driver *to_spi_mem_drv(struct device_driver *drv)
+{
+	return container_of(drv, struct spi_mem_driver, spidrv.driver);
+}
+
+static int spi_mem_probe(struct spi_device *spi)
+{
+	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
+	struct spi_mem *mem;
+
+	mem = devm_kzalloc(&spi->dev, sizeof(*mem), GFP_KERNEL);
+	if (!mem)
+		return -ENOMEM;
+
+	mem->spi = spi;
+	spi_set_drvdata(spi, mem);
+
+	return memdrv->probe(mem);
+}
+
+static int spi_mem_remove(struct spi_device *spi)
+{
+	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
+	struct spi_mem *mem = spi_get_drvdata(spi);
+
+	if (memdrv->remove)
+		return memdrv->remove(mem);
+
+	return 0;
+}
+
+static void spi_mem_shutdown(struct spi_device *spi)
+{
+	struct spi_mem_driver *memdrv = to_spi_mem_drv(spi->dev.driver);
+	struct spi_mem *mem = spi_get_drvdata(spi);
+
+	if (memdrv->shutdown)
+		memdrv->shutdown(mem);
+}
+
+/**
+ * spi_mem_driver_register_with_owner() - Register a SPI memory driver
+ * @memdrv: the SPI memory driver to register
+ * @owner: the owner of this driver
+ *
+ * Registers a SPI memory driver.
+ *
+ * Return: 0 in case of success, a negative error core otherwise.
+ */
+
+int spi_mem_driver_register_with_owner(struct spi_mem_driver *memdrv,
+				       struct module *owner)
+{
+	memdrv->spidrv.probe = spi_mem_probe;
+	memdrv->spidrv.remove = spi_mem_remove;
+	memdrv->spidrv.shutdown = spi_mem_shutdown;
+
+	return __spi_register_driver(owner, &memdrv->spidrv);
+}
+EXPORT_SYMBOL_GPL(spi_mem_driver_register_with_owner);
+
+/**
+ * spi_mem_driver_unregister_with_owner() - Unregister a SPI memory driver
+ * @memdrv: the SPI memory driver to unregister
+ *
+ * Unregisters a SPI memory driver.
+ */
+void spi_mem_driver_unregister(struct spi_mem_driver *memdrv)
+{
+	spi_unregister_driver(&memdrv->spidrv);
+}
+EXPORT_SYMBOL_GPL(spi_mem_driver_unregister);
+#endif /* __UBOOT__ */