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

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: default avatarMark Brown <broonie@kernel.org>
parent 055ed0da
...@@ -47,6 +47,13 @@ config SPI_MASTER ...@@ -47,6 +47,13 @@ config SPI_MASTER
if 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" comment "SPI Master Controller Drivers"
config SPI_ALTERA config SPI_ALTERA
......
...@@ -8,6 +8,7 @@ ccflags-$(CONFIG_SPI_DEBUG) := -DDEBUG ...@@ -8,6 +8,7 @@ ccflags-$(CONFIG_SPI_DEBUG) := -DDEBUG
# small core, mostly translating board-specific # small core, mostly translating board-specific
# config declarations into driver model code # config declarations into driver model code
obj-$(CONFIG_SPI_MASTER) += spi.o obj-$(CONFIG_SPI_MASTER) += spi.o
obj-$(CONFIG_SPI_MEM) += spi-mem.o
obj-$(CONFIG_SPI_SPIDEV) += spidev.o obj-$(CONFIG_SPI_SPIDEV) += spidev.o
obj-$(CONFIG_SPI_LOOPBACK_TEST) += spi-loopback-test.o obj-$(CONFIG_SPI_LOOPBACK_TEST) += spi-loopback-test.o
......
This diff is collapsed.
/* 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
* we might have to stuff more information into the spi_mem struct to let
* SPI controllers know more about the SPI memory they interact with, and
* having this intermediate layer allows us to do that without adding more
* useless fields to the spi_device object.
*/
struct spi_mem_driver {
struct spi_driver spidrv;
int (*probe)(struct spi_mem *mem);
int (*remove)(struct spi_mem *mem);
void (*shutdown)(struct spi_mem *mem);
};
#if IS_ENABLED(CONFIG_SPI_MEM)
int spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
const struct spi_mem_op *op,
struct sg_table *sg);
void spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
const struct spi_mem_op *op,
struct sg_table *sg);
#else
static inline int
spi_controller_dma_map_mem_op_data(struct spi_controller *ctlr,
const struct spi_mem_op *op,
struct sg_table *sg)
{
return -ENOTSUPP;
}
static inline void
spi_controller_dma_unmap_mem_op_data(struct spi_controller *ctlr,
const struct spi_mem_op *op,
struct sg_table *sg)
{
}
#endif /* CONFIG_SPI_MEM */
int spi_mem_adjust_op_size(struct spi_mem *mem, struct spi_mem_op *op);
bool spi_mem_supports_op(struct spi_mem *mem,
const struct spi_mem_op *op);
int spi_mem_exec_op(struct spi_mem *mem,
const struct spi_mem_op *op);
int spi_mem_driver_register_with_owner(struct spi_mem_driver *drv,
struct module *owner);
void spi_mem_driver_unregister(struct spi_mem_driver *drv);
#define spi_mem_driver_register(__drv) \
spi_mem_driver_register_with_owner(__drv, THIS_MODULE)
#define module_spi_mem_driver(__drv) \
module_driver(__drv, spi_mem_driver_register, \
spi_mem_driver_unregister)
#endif /* __LINUX_SPI_MEM_H */
...@@ -27,6 +27,7 @@ struct property_entry; ...@@ -27,6 +27,7 @@ struct property_entry;
struct spi_controller; struct spi_controller;
struct spi_transfer; struct spi_transfer;
struct spi_flash_read_message; struct spi_flash_read_message;
struct spi_controller_mem_ops;
/* /*
* INTERFACES between SPI master-side drivers and SPI slave protocol handlers, * INTERFACES between SPI master-side drivers and SPI slave protocol handlers,
...@@ -376,6 +377,9 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) ...@@ -376,6 +377,9 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv)
* transfer_one callback. * transfer_one callback.
* @handle_err: the subsystem calls the driver to handle an error that occurs * @handle_err: the subsystem calls the driver to handle an error that occurs
* in the generic implementation of transfer_one_message(). * in the generic implementation of transfer_one_message().
* @mem_ops: optimized/dedicated operations for interactions with SPI memory.
* This field is optional and should only be implemented if the
* controller has native support for memory like operations.
* @unprepare_message: undo any work done by prepare_message(). * @unprepare_message: undo any work done by prepare_message().
* @slave_abort: abort the ongoing transfer request on an SPI slave controller * @slave_abort: abort the ongoing transfer request on an SPI slave controller
* @spi_flash_read: to support spi-controller hardwares that provide * @spi_flash_read: to support spi-controller hardwares that provide
...@@ -564,6 +568,9 @@ struct spi_controller { ...@@ -564,6 +568,9 @@ struct spi_controller {
void (*handle_err)(struct spi_controller *ctlr, void (*handle_err)(struct spi_controller *ctlr,
struct spi_message *message); struct spi_message *message);
/* Optimized handlers for SPI memory-like operations. */
const struct spi_controller_mem_ops *mem_ops;
/* gpio chip select */ /* gpio chip select */
int *cs_gpios; int *cs_gpios;
......
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