1 files changed, 289 insertions, 0 deletions
diff --git a/drivers/mtd/spi-mem/spi_mem.c b/drivers/mtd/spi-mem/spi_mem.c
new file mode 100644
index 0000000..c43d519
--- /dev/null
+++ b/drivers/mtd/spi-mem/spi_mem.c
@@ -0,0 +1,289 @@
+/*
+ * Copyright (c) 2019-2022, STMicroelectronics - All Rights Reserved
+ *
+ * SPDX-License-Identifier: BSD-3-Clause
+ */
+
+#include <assert.h>
+#include <inttypes.h>
+#include <stdint.h>
+
+#include <drivers/spi_mem.h>
+#include <lib/utils_def.h>
+#include <libfdt.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:%" PRIx64 " 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 %u 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 %u not supported\n",
+				     fdt32_to_cpu(*cuint));
+				return -EINVAL;
+			}
+		}
+
+		spi_slave.mode = mode;
+		spi_slave.ops = ops;
+	}
+
+	return spi_mem_set_speed_mode();
+}