// SPDX-License-Identifier: GPL-2.0+
/*
* Copyright (C) 2018 Exceet Electronics GmbH
* Copyright (C) 2018 Bootlin
*
* Author: Boris Brezillon <boris.brezillon@bootlin.com>
*/
#include <linux/dmaengine.h>
#include <linux/pm_runtime.h>
#include <linux/spi/spi.h>
#include <linux/spi/spi-mem.h>
#include "internals.h"
/**
* 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);
static int spi_check_buswidth_req(struct spi_mem *mem, u8 buswidth, bool tx)
{
u32 mode = mem->spi->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;
}
static bool spi_mem_default_supports_op(struct spi_mem *mem,
const struct spi_mem_op *op)
{
if (spi_check_buswidth_req(mem, op->cmd.buswidth, true))
return false;
if (op->addr.nbytes &&
spi_check_buswidth_req(mem, op->addr.buswidth, true))
return false;
if (op->dummy.nbytes &&
spi_check_buswidth_req(mem, op->dummy.buswidth, true))
return false;
if (op->data.nbytes &&
spi_check_buswidth_req(mem, 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
* @mem: the SPI memory
* @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_mem *mem, const struct spi_mem_op *op)
{
struct spi_controller *ctlr = mem->spi->controller;
if (ctlr->mem_ops && ctlr->mem_ops->supports_op)
return ctlr->mem_ops->supports_op(mem, op);
return spi_mem_default_supports_op(mem, op);
}
EXPORT_SYMBOL_GPL(spi_mem_supports_op);
/**
* spi_mem_exec_op() - Execute a memory operation
* @mem: the SPI memory
* @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_mem *mem, const struct spi_mem_op *op)
{
unsigned int tmpbufsize, xferpos = 0, totalxferlen = 0;
struct spi_controller *ctlr = mem->spi->controller;
struct spi_transfer xfers[4] = { };
struct spi_message msg;
u8 *tmpbuf;
int ret;
if (!spi_mem_supports_op(mem, op))
return -ENOTSUPP;
if (ctlr->mem_ops) {
/*
* 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);
ret = ctlr->mem_ops->exec_op(mem, op);
mutex_unlock(&ctlr->io_mutex);
mutex_unlock(&ctlr->bus_lock_mutex);
if (ctlr->auto_runtime_pm)
pm_runtime_put(ctlr->dev.parent);
/*
* 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)
return ret;
}
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(mem->spi, &msg);
kfree(tmpbuf);
if (ret)
return ret;
if (msg.actual_length != totalxferlen)
return -EIO;
return 0;
}
EXPORT_SYMBOL_GPL(spi_mem_exec_op);
/**
* spi_mem_get_name() - Return the SPI mem device name to be used by the
* upper layer if necessary
* @mem: the SPI memory
*
* This function allows SPI mem users to retrieve the SPI mem device name.
* It is useful if the upper layer needs to expose a custom name for
* compatibility reasons.
*
* Return: a string containing the name of the memory device to be used
* by the SPI mem user
*/
const char *spi_mem_get_name(struct spi_mem *mem)
{
return mem->name;
}
EXPORT_SYMBOL_GPL(spi_mem_get_name);
/**
* spi_mem_adjust_op_size() - Adjust the data size of a SPI mem operation to
* match controller limitations
* @mem: the SPI memory
* @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_mem *mem, struct spi_mem_op *op)
{
struct spi_controller *ctlr = mem->spi->controller;
if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size)
return ctlr->mem_ops->adjust_op_size(mem, op);
return 0;
}
EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size);
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_controller *ctlr = spi->controller;
struct spi_mem *mem;
mem = devm_kzalloc(&spi->dev, sizeof(*mem), GFP_KERNEL);
if (!mem)
return -ENOMEM;
mem->spi = spi;
if (ctlr->mem_ops && ctlr->mem_ops->get_name)
mem->name = ctlr->mem_ops->get_name(mem);
else
mem->name = dev_name(&spi->dev);
if (IS_ERR_OR_NULL(mem->name))
return PTR_ERR(mem->name);
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);
