flash: add SPI flash driver

include/flash.h

@@ -14,6 +14,7 @@ struct flash_dev {
 	void *priv;
 };
 
+struct flash_dev *flash_probe(void);
 int flash_read(struct flash_dev *dev, uint32_t addr, void *data, size_t len);
 int flash_write(struct flash_dev *dev, uint32_t addr, const void *data,
 	size_t len);

scripts/Makefile.stm32f0

@@ -17,6 +17,7 @@ LIBS += -l$(OPENCM3_LIBNAME)
 STLINK_PORT ?= :4242
 
 obj-y += source/core/spi.o
+obj-y += source/drivers/spi_flash.o
 obj-y += source/drivers/stm32f0_spi.o
 
 $(OPENCM3_DIR)/lib/lib$(OPENCM3_LIBNAME).a:

source/drivers/spi_flash.c

@@ -0,0 +1,154 @@
+#include <stdint.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+#include <flash.h>
+#include <macros.h>
+#include <spi.h>
+
+/* Read commands */
+#define CMD_READ_ARRAY_SLOW		0x03
+#define CMD_READ_ID				0x9f
+
+/* Write commands */
+#define CMD_PAGE_PROGRAM		0x02
+#define CMD_WRITE_DISABLE		0x04
+#define CMD_WRITE_ENABLE		0x06
+
+/* Erase commands */
+#define CMD_ERASE_4K			0x20
+#define CMD_ERASE_32K			0x52
+#define CMD_ERASE_64K			0xD8
+#define CMD_ERASE_CHIP			0x60
+
+static int spi_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
+	size_t len);
+static int spi_flash_write(struct flash_dev *dev, uint32_t addr,
+	const void *data, size_t len);
+static int spi_flash_erase(struct flash_dev *dev, uint32_t addr, size_t len);
+
+static struct flash_ops spi_flash_ops ={
+	.read = spi_flash_read,
+	.write = spi_flash_write,
+	.erase = spi_flash_erase,
+};
+
+static void spi_flash_addr(char *cmd, uint32_t addr)
+{
+	cmd[1] = addr >> 16;
+	cmd[2] = addr >> 8;
+	cmd[3] = addr;
+}
+
+static void spi_flash_write_enable(struct flash_dev *dev)
+{
+	char cmd[1] = { CMD_WRITE_ENABLE };
+	struct spi_dev *spi_dev = dev->priv;
+
+	spi_set_cs_level(spi_dev, 0);
+	spi_tx_rx(spi_dev, NULL, cmd, sizeof cmd);
+	spi_set_cs_level(spi_dev, 1);
+}
+
+static void spi_flash_write_disable(struct flash_dev *dev)
+{
+	char cmd[1] = { CMD_WRITE_DISABLE };
+	struct spi_dev *spi_dev = dev->priv;
+
+	spi_set_cs_level(spi_dev, 0);
+	spi_tx_rx(spi_dev, NULL, cmd, sizeof cmd);
+	spi_set_cs_level(spi_dev, 1);
+}
+
+static int spi_flash_read(struct flash_dev *dev, uint32_t addr, void *data,
+	size_t len)
+{
+	char cmd[4] = { CMD_READ_ARRAY_SLOW };
+	struct spi_dev *spi_dev = dev->priv;
+
+	spi_flash_addr(cmd, addr);
+
+	spi_set_cs_level(spi_dev, 0);
+	spi_tx_rx(spi_dev, NULL, cmd, sizeof cmd);
+	spi_tx_rx(spi_dev, data, NULL, len);
+	spi_set_cs_level(spi_dev, 1);
+
+	return 0;
+}
+
+static int spi_flash_write(struct flash_dev *dev, uint32_t addr,
+	const void *data, size_t len)
+{
+	char cmd[4] = { CMD_PAGE_PROGRAM };
+	struct spi_dev *spi_dev = dev->priv;
+
+	spi_flash_write_enable(dev);
+	spi_flash_addr(cmd, addr);
+
+	spi_set_cs_level(spi_dev, 0);
+	spi_tx_rx(spi_dev, NULL, cmd, sizeof cmd);
+	spi_tx_rx(spi_dev, NULL, data, len);
+	spi_set_cs_level(spi_dev, 1);
+
+	spi_flash_write_disable(dev);
+
+	return 0;
+}
+
+static int spi_flash_erase(struct flash_dev *dev, uint32_t addr, size_t len)
+{
+	char cmd[4];
+	struct spi_dev *spi_dev = dev->priv;
+	size_t size = 0;
+
+	spi_flash_write_enable(dev);
+	addr = ROUND_UP(addr, 4 * KIB);
+
+	for (; len; addr += size, len -= size) {
+		if (IS_ROUND(addr, 64 * KIB) && IS_ROUND(len, 64 * KIB))
+			size = 64 * KIB;
+		else if (IS_ROUND(addr, 32 * KIB) && IS_ROUND(len, 32 * KIB))
+			size = 32 * KIB;
+		else if (IS_ROUND(addr, 4 * KIB) && IS_ROUND(len, 4 * KIB))
+			size = 4 * KIB;
+		else
+			size = 0;
+
+		switch (size) {
+		case 64 * KIB: cmd[0] = CMD_ERASE_64K; break;
+		case 32 * KIB: cmd[0] = CMD_ERASE_32K; break;
+		case 4 * KIB: cmd[0] = CMD_ERASE_4K; break;
+		default: goto err_disable_write;
+		};
+
+		printf("addr: %lx; size: %u\n", addr, size);
+		spi_flash_addr(cmd, addr);
+
+		spi_set_cs_level(spi_dev, 0);
+		spi_tx_rx(spi_dev, NULL, cmd, sizeof cmd);
+		spi_set_cs_level(spi_dev, 1);
+	}
+
+err_disable_write:
+	spi_flash_write_disable(dev);
+	return 0;
+}
+
+struct flash_dev *flash_probe(void)
+{
+	struct flash_dev *dev;
+
+	if (!(dev = malloc(sizeof *dev)))
+		return NULL;
+
+	if (!(dev->priv = spi_probe()))
+		goto err_free_dev;
+
+	dev->ops = &spi_flash_ops;
+
+	return dev;
+
+err_free_dev:
+	free(dev);
+	return NULL;
+}