[v2,04/10] spi: Extend the core to ease integration of SPI memory controllers

Message ID	20180410224439.9260-5-boris.brezillon@bootlin.com (mailing list archive)
State	New, archived
Headers	show Return-Path: <linux-spi-owner@kernel.org> From: Boris Brezillon <boris.brezillon@bootlin.com> To: David Woodhouse <dwmw2@infradead.org>, Brian Norris <computersforpeace@gmail.com>, Boris Brezillon <boris.brezillon@bootlin.com>, Marek Vasut <marek.vasut@gmail.com>, Richard Weinberger <richard@nod.at>, Cyrille Pitchen <cyrille.pitchen@wedev4u.fr>, linux-mtd@lists.infradead.org, Miquel Raynal <miquel.raynal@bootlin.com>, Mark Brown <broonie@kernel.org>, linux-spi@vger.kernel.org Cc: Peter Pan <peterpansjtu@gmail.com>, Frieder Schrempf <frieder.schrempf@exceet.de>, Vignesh R <vigneshr@ti.com>, Yogesh Gaur <yogeshnarayan.gaur@nxp.com>, =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>, Kamal Dasu <kdasu.kdev@gmail.com>, Sourav Poddar <sourav.poddar@ti.com>, Maxime Chevallier <maxime.chevallier@bootlin.com> Subject: [PATCH v2 04/10] spi: Extend the core to ease integration of SPI memory controllers Date: Wed, 11 Apr 2018 00:44:33 +0200 Message-Id: <20180410224439.9260-5-boris.brezillon@bootlin.com> In-Reply-To: <20180410224439.9260-1-boris.brezillon@bootlin.com> References: <20180410224439.9260-1-boris.brezillon@bootlin.com> Sender: linux-spi-owner@vger.kernel.org Precedence: bulk

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index 2d4146ce2f1b..59936ab80a0d 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -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 diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index b935f10eb961..79d6f1c7b05b 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -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 diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c new file mode 100644 index 000000000000..2e6494be045c --- /dev/null +++ b/drivers/spi/spi-mem.c @@ -0,0 +1,408 @@ +// 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> + +/** + * 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->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); diff --git a/include/linux/spi/spi-mem.h b/include/linux/spi/spi-mem.h new file mode 100644 index 000000000000..ac2e8d8f45cd --- /dev/null +++ b/include/linux/spi/spi-mem.h @@ -0,0 +1,249 @@ +// 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 */ diff --git a/include/linux/spi/spi.h b/include/linux/spi/spi.h index 3489fc9c0410..fb247a26fed9 100644 --- a/include/linux/spi/spi.h +++ b/include/linux/spi/spi.h @@ -28,6 +28,7 @@ struct property_entry; struct spi_controller; struct spi_transfer; struct spi_flash_read_message; +struct spi_controller_mem_ops; /* * INTERFACES between SPI master-side drivers and SPI slave protocol handlers, @@ -377,6 +378,9 @@ static inline void spi_unregister_driver(struct spi_driver *sdrv) * transfer_one callback. * @handle_err: the subsystem calls the driver to handle an error that occurs * 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(). * @slave_abort: abort the ongoing transfer request on an SPI slave controller * @spi_flash_read: to support spi-controller hardwares that provide @@ -565,6 +569,9 @@ struct spi_controller { void (*handle_err)(struct spi_controller *ctlr, struct spi_message *message); + /* Optimized handlers for SPI memory-like operations. */ + const struct spi_controller_mem_ops *mem_ops; + /* gpio chip select */ int *cs_gpios;

[v2,04/10] spi: Extend the core to ease integration of SPI memory controllers

Commit Message

Comments

Patch