spi-mem.c

// 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 <linux/dmaengine.h>
#include <linux/pm_runtime.h>
#include "internals.h"
#else
#include <spi.h>
#include <spi-mem.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;

	default:
		break;
	}

	return -ENOTSUPP;
}

bool spi_mem_default_supports_op(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.nbytes &&
	    spi_check_buswidth_req(slave, op->data.buswidth,
				   op->data.dir == SPI_MEM_DATA_OUT))
		return false;

	return true;
}
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 = sizeof(op->cmd.opcode) + 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 = sizeof(op->cmd.opcode);
	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 = sizeof(op->cmd.opcode) + 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 = sizeof(op->cmd.opcode) + 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);

#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__ */