Verified Commit c36ff266 authored by Boris Brezillon's avatar Boris Brezillon Committed by Mark Brown
Browse files

spi: Extend the core to ease integration of SPI memory controllers



Some controllers are exposing high-level interfaces to access various
kind of SPI memories. Unfortunately they do not fit in the current
spi_controller model and usually have drivers placed in
drivers/mtd/spi-nor which are only supporting SPI NORs and not SPI
memories in general.

This is an attempt at defining a SPI memory interface which works for
all kinds of SPI memories (NORs, NANDs, SRAMs).

Signed-off-by: default avatarBoris Brezillon <boris.brezillon@bootlin.com>
Reviewed-by: default avatarFrieder Schrempf <frieder.schrempf@exceet.de>
Tested-by: default avatarFrieder Schrempf <frieder.schrempf@exceet.de>
Signed-off-by: Mark Brown's avatarMark Brown <broonie@kernel.org>
parent 055ed0da
......@@ -47,6 +47,13 @@ config SPI_MASTER
if SPI_MASTER
config SPI_MEM
bool "SPI memory extension"
help
Enable this option if you want to enable the SPI memory extension.
This extension is meant to simplify interaction with SPI memories
by providing an high-level interface to send memory-like commands.
comment "SPI Master Controller Drivers"
config SPI_ALTERA
......
......@@ -8,6 +8,7 @@ ccflags-$(CONFIG_SPI_DEBUG) := -DDEBUG
# small core, mostly translating board-specific
# config declarations into driver model code
obj-$(CONFIG_SPI_MASTER) += spi.o
obj-$(CONFIG_SPI_MEM) += spi-mem.o
obj-$(CONFIG_SPI_SPIDEV) += spidev.o
obj-$(CONFIG_SPI_LOOPBACK_TEST) += spi-loopback-test.o
......
// 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_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_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);
/* SPDX-License-Identifier: GPL-2.0+ */
/*
* Copyright (C) 2018 Exceet Electronics GmbH
* Copyright (C) 2018 Bootlin
*
* Author: Boris Brezillon <boris.brezillon@bootlin.com>
*/
#ifndef __LINUX_SPI_MEM_H
#define __LINUX_SPI_MEM_H
#include <linux/spi/spi.h>
#define SPI_MEM_OP_CMD(__opcode, __buswidth) \
{ \
.buswidth = __buswidth, \
.opcode = __opcode, \
}
#define SPI_MEM_OP_ADDR(__nbytes, __val, __buswidth) \
{ \
.nbytes = __nbytes, \
.val = __val, \
.buswidth = __buswidth, \
}
#define SPI_MEM_OP_NO_ADDR { }
#define SPI_MEM_OP_DUMMY(__nbytes, __buswidth) \
{ \
.nbytes = __nbytes, \
.buswidth = __buswidth, \
}
#define SPI_MEM_OP_NO_DUMMY { }
#define SPI_MEM_OP_DATA_IN(__nbytes, __buf, __buswidth) \
{ \
.dir = SPI_MEM_DATA_IN, \
.nbytes = __nbytes, \
.buf.in = __buf, \
.buswidth = __buswidth, \
}
#define SPI_MEM_OP_DATA_OUT(__nbytes, __buf, __buswidth) \
{ \
.dir = SPI_MEM_DATA_OUT, \
.nbytes = __nbytes, \
.buf.out = __buf, \
.buswidth = __buswidth, \
}
#define SPI_MEM_OP_NO_DATA { }
/**
* enum spi_mem_data_dir - describes the direction of a SPI memory data
* transfer from the controller perspective
* @SPI_MEM_DATA_IN: data coming from the SPI memory
* @SPI_MEM_DATA_OUT: data sent the SPI memory
*/
enum spi_mem_data_dir {
SPI_MEM_DATA_IN,
SPI_MEM_DATA_OUT,
};
/**
* struct spi_mem_op - describes a SPI memory operation
* @cmd.buswidth: number of IO lines used to transmit the command
* @cmd.opcode: operation opcode
* @addr.nbytes: number of address bytes to send. Can be zero if the operation
* does not need to send an address
* @addr.buswidth: number of IO lines used to transmit the address cycles
* @addr.val: address value. This value is always sent MSB first on the bus.
* Note that only @addr.nbytes are taken into account in this
* address value, so users should make sure the value fits in the
* assigned number of bytes.
* @dummy.nbytes: number of dummy bytes to send after an opcode or address. Can
* be zero if the operation does not require dummy bytes
* @dummy.buswidth: number of IO lanes used to transmit the dummy bytes
* @data.buswidth: number of IO lanes used to send/receive the data
* @data.dir: direction of the transfer
* @data.buf.in: input buffer
* @data.buf.out: output buffer
*/
struct spi_mem_op {
struct {
u8 buswidth;
u8 opcode;
} cmd;
struct {
u8 nbytes;
u8 buswidth;
u64 val;
} addr;
struct {
u8 nbytes;
u8 buswidth;
} dummy;
struct {
u8 buswidth;
enum spi_mem_data_dir dir;
unsigned int nbytes;
/* buf.{in,out} must be DMA-able. */
union {
void *in;
const void *out;
} buf;
} data;
};
#define SPI_MEM_OP(__cmd, __addr, __dummy, __data) \
{ \
.cmd = __cmd, \
.addr = __addr, \
.dummy = __dummy, \
.data = __data, \
}
/**
* struct spi_mem - describes a SPI memory device
* @spi: the underlying SPI device
* @drvpriv: spi_mem_drviver private data
*
* Extra information that describe the SPI memory device and may be needed by
* the controller to properly handle this device should be placed here.
*
* One example would be the device size since some controller expose their SPI
* mem devices through a io-mapped region.
*/
struct spi_mem {
struct spi_device *spi;
void *drvpriv;
};
/**
* struct spi_mem_set_drvdata() - attach driver private data to a SPI mem
* device
* @mem: memory device
* @data: data to attach to the memory device
*/
static inline void spi_mem_set_drvdata(struct spi_mem *mem, void *data)
{
mem->drvpriv = data;
}
/**
* struct spi_mem_get_drvdata() - get driver private data attached to a SPI mem
* device
* @mem: memory device
*
* Return: the data attached to the mem device.
*/
static inline void *spi_mem_get_drvdata(struct spi_mem *mem)
{
return mem->drvpriv;
}
/**
* struct spi_controller_mem_ops - SPI memory operations
* @adjust_op_size: shrink the data xfer of an operation to match controller's
* limitations (can be alignment of max RX/TX size
* limitations)
* @supports_op: check if an operation is supported by the controller
* @exec_op: execute a SPI memory operation
*
* This interface should be implemented by SPI controllers providing an
* high-level interface to execute SPI memory operation, which is usually the
* case for QSPI controllers.
*/
struct spi_controller_mem_ops {
int (*adjust_op_size)(struct spi_mem *mem, struct spi_mem_op *op);
bool (*supports_op)(struct spi_mem *mem,
const struct spi_mem_op *op);
int (*exec_op)(struct spi_mem *mem,
const struct spi_mem_op *op);
};
/**
* struct spi_mem_driver - SPI memory driver
* @spidrv: inherit from a SPI driver
* @probe: probe a SPI memory. Usually where detection/initialization takes
* place
* @remove: remove a SPI memory
* @shutdown: take appropriate action when the system is shutdown
*
* This is just a thin wrapper around a spi_driver. The core takes care of
* allocating the spi_mem object and forwarding the probe/remove/shutdown
* request to the spi_mem_driver. The reason we use this wrapper is because