diff options
Diffstat (limited to 'drivers/spi/spi-mem.c')
| -rw-r--r-- | drivers/spi/spi-mem.c | 410 |
1 files changed, 410 insertions, 0 deletions
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c new file mode 100644 index 000000000000..990770dfa5cf --- /dev/null +++ b/drivers/spi/spi-mem.c @@ -0,0 +1,410 @@ +// 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); |