// SPDX-License-Identifier: GPL-2.0+ /* * Copyright (C) 2018 Exceet Electronics GmbH * Copyright (C) 2018 Bootlin * * Author: Boris Brezillon */ #include #include #include #include #include #define SPI_MEM_MAX_BUSWIDTH 8 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; case 8: if ((tx && (mode & SPI_TX_OCTAL)) || (!tx && (mode & SPI_RX_OCTAL))) 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.dir != SPI_MEM_NO_DATA && 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); static bool spi_mem_buswidth_is_valid(u8 buswidth) { if (hweight8(buswidth) > 1 || buswidth > SPI_MEM_MAX_BUSWIDTH) return false; return true; } static int spi_mem_check_op(const struct spi_mem_op *op) { if (!op->cmd.buswidth) return -EINVAL; if ((op->addr.nbytes && !op->addr.buswidth) || (op->dummy.nbytes && !op->dummy.buswidth) || (op->data.nbytes && !op->data.buswidth)) return -EINVAL; if (!spi_mem_buswidth_is_valid(op->cmd.buswidth) || !spi_mem_buswidth_is_valid(op->addr.buswidth) || !spi_mem_buswidth_is_valid(op->dummy.buswidth) || !spi_mem_buswidth_is_valid(op->data.buswidth)) return -EINVAL; return 0; } static bool spi_mem_internal_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); } /** * 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) { if (spi_mem_check_op(op)) return false; return spi_mem_internal_supports_op(mem, op); } EXPORT_SYMBOL_GPL(spi_mem_supports_op); static int spi_mem_access_start(struct spi_mem *mem) { return 0; } static void spi_mem_access_end(struct spi_mem *mem) { return; } /** * 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; ret = spi_mem_check_op(op); if (ret) return ret; if (!spi_mem_internal_supports_op(mem, op)) return -ENOTSUPP; if (ctlr->mem_ops) { ret = spi_mem_access_start(mem); if (ret) return ret; ret = ctlr->mem_ops->exec_op(mem, op); spi_mem_access_end(mem); /* * 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); 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); 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; 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; 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; else xfers[xferpos].tx_buf = op->data.buf.out; 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; size_t len; len = sizeof(op->cmd.opcode) + op->addr.nbytes + op->dummy.nbytes; if (ctlr->mem_ops && ctlr->mem_ops->adjust_op_size) return ctlr->mem_ops->adjust_op_size(mem, op); if (!ctlr->mem_ops || !ctlr->mem_ops->exec_op) { if (len > spi_max_transfer_size(mem->spi)) return -EINVAL; op->data.nbytes = min3((size_t)op->data.nbytes, spi_max_transfer_size(mem->spi), spi_max_message_size(mem->spi) - len); if (!op->data.nbytes) return -EINVAL; } return 0; } EXPORT_SYMBOL_GPL(spi_mem_adjust_op_size); static ssize_t spi_mem_no_dirmap_read(struct spi_mem_dirmap_desc *desc, u64 offs, size_t len, void *buf) { struct spi_mem_op op = desc->info.op_tmpl; int ret; op.addr.val = desc->info.offset + offs; op.data.buf.in = buf; op.data.nbytes = len; ret = spi_mem_adjust_op_size(desc->mem, &op); if (ret) return ret; ret = spi_mem_exec_op(desc->mem, &op); if (ret) return ret; return op.data.nbytes; } static ssize_t spi_mem_no_dirmap_write(struct spi_mem_dirmap_desc *desc, u64 offs, size_t len, const void *buf) { struct spi_mem_op op = desc->info.op_tmpl; int ret; op.addr.val = desc->info.offset + offs; op.data.buf.out = buf; op.data.nbytes = len; ret = spi_mem_adjust_op_size(desc->mem, &op); if (ret) return ret; ret = spi_mem_exec_op(desc->mem, &op); if (ret) return ret; return op.data.nbytes; } /** * spi_mem_dirmap_create() - Create a direct mapping descriptor * @mem: SPI mem device this direct mapping should be created for * @info: direct mapping information * * This function is creating a direct mapping descriptor which can then be used * to access the memory using spi_mem_dirmap_read() or spi_mem_dirmap_write(). * If the SPI controller driver does not support direct mapping, this function * fallback to an implementation using spi_mem_exec_op(), so that the caller * doesn't have to bother implementing a fallback on his own. * * Return: a valid pointer in case of success, and ERR_PTR() otherwise. */ struct spi_mem_dirmap_desc * spi_mem_dirmap_create(struct spi_mem *mem, const struct spi_mem_dirmap_info *info) { struct spi_controller *ctlr = mem->spi->controller; struct spi_mem_dirmap_desc *desc; int ret = -ENOTSUPP; /* Make sure the number of address cycles is between 1 and 8 bytes. */ if (!info->op_tmpl.addr.nbytes || info->op_tmpl.addr.nbytes > 8) return ERR_PTR(-EINVAL); /* data.dir should either be SPI_MEM_DATA_IN or SPI_MEM_DATA_OUT. */ if (info->op_tmpl.data.dir == SPI_MEM_NO_DATA) return ERR_PTR(-EINVAL); desc = kzalloc(sizeof(*desc), GFP_KERNEL); if (!desc) return ERR_PTR(-ENOMEM); desc->mem = mem; desc->info = *info; if (ctlr->mem_ops && ctlr->mem_ops->dirmap_create) ret = ctlr->mem_ops->dirmap_create(desc); if (ret) { desc->nodirmap = true; if (!spi_mem_supports_op(desc->mem, &desc->info.op_tmpl)) ret = -ENOTSUPP; else ret = 0; } if (ret) { kfree(desc); return ERR_PTR(ret); } return desc; } EXPORT_SYMBOL_GPL(spi_mem_dirmap_create); /** * spi_mem_dirmap_destroy() - Destroy a direct mapping descriptor * @desc: the direct mapping descriptor to destroy * @info: direct mapping information * * This function destroys a direct mapping descriptor previously created by * spi_mem_dirmap_create(). */ void spi_mem_dirmap_destroy(struct spi_mem_dirmap_desc *desc) { struct spi_controller *ctlr = desc->mem->spi->controller; if (!desc->nodirmap && ctlr->mem_ops && ctlr->mem_ops->dirmap_destroy) ctlr->mem_ops->dirmap_destroy(desc); } EXPORT_SYMBOL_GPL(spi_mem_dirmap_destroy); /** * spi_mem_dirmap_dirmap_read() - Read data through a direct mapping * @desc: direct mapping descriptor * @offs: offset to start reading from. Note that this is not an absolute * offset, but the offset within the direct mapping which already has * its own offset * @len: length in bytes * @buf: destination buffer. This buffer must be DMA-able * * This function reads data from a memory device using a direct mapping * previously instantiated with spi_mem_dirmap_create(). * * Return: the amount of data read from the memory device or a negative error * code. Note that the returned size might be smaller than @len, and the caller * is responsible for calling spi_mem_dirmap_read() again when that happens. */ ssize_t spi_mem_dirmap_read(struct spi_mem_dirmap_desc *desc, u64 offs, size_t len, void *buf) { struct spi_controller *ctlr = desc->mem->spi->controller; ssize_t ret; if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_IN) return -EINVAL; if (!len) return 0; if (desc->nodirmap) { ret = spi_mem_no_dirmap_read(desc, offs, len, buf); } else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_read) { ret = spi_mem_access_start(desc->mem); if (ret) return ret; ret = ctlr->mem_ops->dirmap_read(desc, offs, len, buf); spi_mem_access_end(desc->mem); } else { ret = -ENOTSUPP; } return ret; } EXPORT_SYMBOL_GPL(spi_mem_dirmap_read); /** * spi_mem_dirmap_dirmap_write() - Write data through a direct mapping * @desc: direct mapping descriptor * @offs: offset to start writing from. Note that this is not an absolute * offset, but the offset within the direct mapping which already has * its own offset * @len: length in bytes * @buf: source buffer. This buffer must be DMA-able * * This function writes data to a memory device using a direct mapping * previously instantiated with spi_mem_dirmap_create(). * * Return: the amount of data written to the memory device or a negative error * code. Note that the returned size might be smaller than @len, and the caller * is responsible for calling spi_mem_dirmap_write() again when that happens. */ ssize_t spi_mem_dirmap_write(struct spi_mem_dirmap_desc *desc, u64 offs, size_t len, const void *buf) { struct spi_controller *ctlr = desc->mem->spi->controller; ssize_t ret; if (desc->info.op_tmpl.data.dir != SPI_MEM_DATA_OUT) return -EINVAL; if (!len) return 0; if (desc->nodirmap) { ret = spi_mem_no_dirmap_write(desc, offs, len, buf); } else if (ctlr->mem_ops && ctlr->mem_ops->dirmap_write) { ret = spi_mem_access_start(desc->mem); if (ret) return ret; ret = ctlr->mem_ops->dirmap_write(desc, offs, len, buf); spi_mem_access_end(desc->mem); } else { ret = -ENOTSUPP; } return ret; } EXPORT_SYMBOL_GPL(spi_mem_dirmap_write);