Add SPI-MEM framework
This framework supports SPI operations using a common
spi_mem_op structure:
- command
- addr
- dummy
- data
The framework manages SPI bus configuration:
- speed
- bus width (Up to quad mode)
- chip select
Change-Id: Idc2736c59bfc5ac6e55429eba5d385275ea3fbde
Signed-off-by: Lionel Debieve <lionel.debieve@st.com>
Signed-off-by: Christophe Kerello <christophe.kerello@st.com>
diff --git a/drivers/mtd/spi-mem/spi_mem.c b/drivers/mtd/spi-mem/spi_mem.c
new file mode 100644
index 0000000..63ea769
--- /dev/null
+++ b/drivers/mtd/spi-mem/spi_mem.c
@@ -0,0 +1,288 @@
+/*
+ * Copyright (c) 2019, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+
+#include <libfdt.h>
+
+#include <drivers/spi_mem.h>
+#include <lib/utils_def.h>
+
+#define SPI_MEM_DEFAULT_SPEED_HZ 100000U
+
+/*
+ * struct spi_slave - Representation of a SPI slave.
+ *
+ * @max_hz: Maximum speed for this slave in Hertz.
+ * @cs: ID of the chip select connected to the slave.
+ * @mode: SPI mode to use for this slave (see SPI mode flags).
+ * @ops: Ops defined by the bus.
+ */
+struct spi_slave {
+ unsigned int max_hz;
+ unsigned int cs;
+ unsigned int mode;
+ const struct spi_bus_ops *ops;
+};
+
+static struct spi_slave spi_slave;
+
+static bool spi_mem_check_buswidth_req(uint8_t buswidth, bool tx)
+{
+ switch (buswidth) {
+ case 1U:
+ return true;
+
+ case 2U:
+ if ((tx && (spi_slave.mode & (SPI_TX_DUAL | SPI_TX_QUAD)) !=
+ 0U) ||
+ (!tx && (spi_slave.mode & (SPI_RX_DUAL | SPI_RX_QUAD)) !=
+ 0U)) {
+ return true;
+ }
+ break;
+
+ case 4U:
+ if ((tx && (spi_slave.mode & SPI_TX_QUAD) != 0U) ||
+ (!tx && (spi_slave.mode & SPI_RX_QUAD) != 0U)) {
+ return true;
+ }
+ break;
+
+ default:
+ break;
+ }
+
+ return false;
+}
+
+static bool spi_mem_supports_op(const struct spi_mem_op *op)
+{
+ if (!spi_mem_check_buswidth_req(op->cmd.buswidth, true)) {
+ return false;
+ }
+
+ if ((op->addr.nbytes != 0U) &&
+ !spi_mem_check_buswidth_req(op->addr.buswidth, true)) {
+ return false;
+ }
+
+ if ((op->dummy.nbytes != 0U) &&
+ !spi_mem_check_buswidth_req(op->dummy.buswidth, true)) {
+ return false;
+ }
+
+ if ((op->data.nbytes != 0U) &&
+ !spi_mem_check_buswidth_req(op->data.buswidth,
+ op->data.dir == SPI_MEM_DATA_OUT)) {
+ return false;
+ }
+
+ return true;
+}
+
+static int spi_mem_set_speed_mode(void)
+{
+ const struct spi_bus_ops *ops = spi_slave.ops;
+ int ret;
+
+ ret = ops->set_speed(spi_slave.max_hz);
+ if (ret != 0) {
+ VERBOSE("Cannot set speed (err=%d)\n", ret);
+ return ret;
+ }
+
+ ret = ops->set_mode(spi_slave.mode);
+ if (ret != 0) {
+ VERBOSE("Cannot set mode (err=%d)\n", ret);
+ return ret;
+ }
+
+ return 0;
+}
+
+static int spi_mem_check_bus_ops(const struct spi_bus_ops *ops)
+{
+ bool error = false;
+
+ if (ops->claim_bus == NULL) {
+ VERBOSE("Ops claim bus is not defined\n");
+ error = true;
+ }
+
+ if (ops->release_bus == NULL) {
+ VERBOSE("Ops release bus is not defined\n");
+ error = true;
+ }
+
+ if (ops->exec_op == NULL) {
+ VERBOSE("Ops exec op is not defined\n");
+ error = true;
+ }
+
+ if (ops->set_speed == NULL) {
+ VERBOSE("Ops set speed is not defined\n");
+ error = true;
+ }
+
+ if (ops->set_mode == NULL) {
+ VERBOSE("Ops set mode is not defined\n");
+ error = true;
+ }
+
+ return error ? -EINVAL : 0;
+}
+
+/*
+ * spi_mem_exec_op() - Execute a memory operation.
+ * @op: The memory operation to execute.
+ *
+ * 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(const struct spi_mem_op *op)
+{
+ const struct spi_bus_ops *ops = spi_slave.ops;
+ int ret;
+
+ VERBOSE("%s: cmd:%x mode:%d.%d.%d.%d addqr:%llx len:%x\n",
+ __func__, op->cmd.opcode, op->cmd.buswidth, op->addr.buswidth,
+ op->dummy.buswidth, op->data.buswidth,
+ op->addr.val, op->data.nbytes);
+
+ if (!spi_mem_supports_op(op)) {
+ WARN("Error in spi_mem_support\n");
+ return -ENOTSUP;
+ }
+
+ ret = ops->claim_bus(spi_slave.cs);
+ if (ret != 0) {
+ WARN("Error claim_bus\n");
+ return ret;
+ }
+
+ ret = ops->exec_op(op);
+
+ ops->release_bus();
+
+ return ret;
+}
+
+/*
+ * spi_mem_init_slave() - SPI slave device initialization.
+ * @fdt: Pointer to the device tree blob.
+ * @bus_node: Offset of the bus node.
+ * @ops: The SPI bus ops defined.
+ *
+ * This function first checks that @ops are supported and then tries to find
+ * a SPI slave device.
+ *
+ * Return: 0 in case of success, a negative error code otherwise.
+ */
+int spi_mem_init_slave(void *fdt, int bus_node, const struct spi_bus_ops *ops)
+{
+ int ret;
+ int mode = 0;
+ int nchips = 0;
+ int bus_subnode = 0;
+ const fdt32_t *cuint = NULL;
+
+ ret = spi_mem_check_bus_ops(ops);
+ if (ret != 0) {
+ return ret;
+ }
+
+ fdt_for_each_subnode(bus_subnode, fdt, bus_node) {
+ nchips++;
+ }
+
+ if (nchips != 1) {
+ ERROR("Only one SPI device is currently supported\n");
+ return -EINVAL;
+ }
+
+ fdt_for_each_subnode(bus_subnode, fdt, bus_node) {
+ /* Get chip select */
+ cuint = fdt_getprop(fdt, bus_subnode, "reg", NULL);
+ if (cuint == NULL) {
+ ERROR("Chip select not well defined\n");
+ return -EINVAL;
+ }
+ spi_slave.cs = fdt32_to_cpu(*cuint);
+
+ /* Get max slave frequency */
+ spi_slave.max_hz = SPI_MEM_DEFAULT_SPEED_HZ;
+ cuint = fdt_getprop(fdt, bus_subnode,
+ "spi-max-frequency", NULL);
+ if (cuint != NULL) {
+ spi_slave.max_hz = fdt32_to_cpu(*cuint);
+ }
+
+ /* Get mode */
+ if ((fdt_getprop(fdt, bus_subnode, "spi-cpol", NULL)) != NULL) {
+ mode |= SPI_CPOL;
+ }
+ if ((fdt_getprop(fdt, bus_subnode, "spi-cpha", NULL)) != NULL) {
+ mode |= SPI_CPHA;
+ }
+ if ((fdt_getprop(fdt, bus_subnode, "spi-cs-high", NULL)) !=
+ NULL) {
+ mode |= SPI_CS_HIGH;
+ }
+ if ((fdt_getprop(fdt, bus_subnode, "spi-3wire", NULL)) !=
+ NULL) {
+ mode |= SPI_3WIRE;
+ }
+ if ((fdt_getprop(fdt, bus_subnode, "spi-half-duplex", NULL)) !=
+ NULL) {
+ mode |= SPI_PREAMBLE;
+ }
+
+ /* Get dual/quad mode */
+ cuint = fdt_getprop(fdt, bus_subnode, "spi-tx-bus-width", NULL);
+ if (cuint != NULL) {
+ switch (fdt32_to_cpu(*cuint)) {
+ case 1U:
+ break;
+ case 2U:
+ mode |= SPI_TX_DUAL;
+ break;
+ case 4U:
+ mode |= SPI_TX_QUAD;
+ break;
+ default:
+ WARN("spi-tx-bus-width %d not supported\n",
+ fdt32_to_cpu(*cuint));
+ return -EINVAL;
+ }
+ }
+
+ cuint = fdt_getprop(fdt, bus_subnode, "spi-rx-bus-width", NULL);
+ if (cuint != NULL) {
+ switch (fdt32_to_cpu(*cuint)) {
+ case 1U:
+ break;
+ case 2U:
+ mode |= SPI_RX_DUAL;
+ break;
+ case 4U:
+ mode |= SPI_RX_QUAD;
+ break;
+ default:
+ WARN("spi-rx-bus-width %d not supported\n",
+ fdt32_to_cpu(*cuint));
+ return -EINVAL;
+ }
+ }
+
+ spi_slave.mode = mode;
+ spi_slave.ops = ops;
+ }
+
+ return spi_mem_set_speed_mode();
+}