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authorSascha Hauer <s.hauer@pengutronix.de>2019-05-10 18:15:50 +0200
committerSascha Hauer <s.hauer@pengutronix.de>2019-05-10 18:15:50 +0200
commit5fdedd222f566b61f9e5c9278e10af777384e9b4 (patch)
tree7db078612b2ab29f516bcb5bbf83fe7afc3da50d /drivers/spi/spi-mem.c
parent6a4f6bf4493031c8d655f0506819d4788c9a7553 (diff)
parent89d1d8c9a7266d62abf0ae03513a539be2120077 (diff)
downloadbarebox-5fdedd222f566b61f9e5c9278e10af777384e9b4.tar.gz
Merge branch 'for-next/qspi'
Diffstat (limited to 'drivers/spi/spi-mem.c')
-rw-r--r--drivers/spi/spi-mem.c524
1 files changed, 524 insertions, 0 deletions
diff --git a/drivers/spi/spi-mem.c b/drivers/spi/spi-mem.c
new file mode 100644
index 0000000..b438ed3
--- /dev/null
+++ b/drivers/spi/spi-mem.c
@@ -0,0 +1,524 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Copyright (C) 2018 Exceet Electronics GmbH
+ * Copyright (C) 2018 Bootlin
+ *
+ * Author: Boris Brezillon <boris.brezillon@bootlin.com>
+ */
+#include <common.h>
+#include <module.h>
+#include <linux/kernel.h>
+#include <linux/spi/spi-mem.h>
+#include <spi/spi.h>
+
+#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);