+/**
+ * @defgroup spicmds SPI commands
+ * @{
+ */
+
+/** Write status register */
+#define SPI_WRSR 0x01
+
+/** Write data to memory array */
+#define SPI_WRITE 0x02
+
+/** Read data from memory array */
+#define SPI_READ 0x03
+
+/** Reset write enable latch */
+#define SPI_WRDI 0x04
+
+/** Read status register */
+#define SPI_RDSR 0x05
+
+/** Set write enable latch */
+#define SPI_WREN 0x06
+
+/**
+ * @defgroup atmelcmds Atmel-specific SPI commands
+ * @{
+ */
+
+/** Erase one sector in memory array (Not supported on all devices) */
+#define ATMEL_SECTOR_ERASE 0x52
+
+/** Erase all sections in memory array (Not supported on all devices) */
+#define ATMEL_CHIP_ERASE 0x62
+
+/** Read manufacturer and product ID (Not supported on all devices) */
+#define ATMEL_RDID 0x15
+
+/** @} */
+
+/** @} */
+
+/**
+ * @defgroup spistatus SPI status register bits (not present on all devices)
+ * @{
+ */
+
+/** Write-protect pin enabled */
+#define SPI_STATUS_WPEN 0x80
+
+/** Block protection bit 2 */
+#define SPI_STATUS_BP2 0x10
+
+/** Block protection bit 1 */
+#define SPI_STATUS_BP1 0x08
+
+/** Block protection bit 0 */
+#define SPI_STATUS_BP0 0x04
+
+/** State of the write enable latch */
+#define SPI_STATUS_WEN 0x02
+
+/** Device busy flag */
+#define SPI_STATUS_NRDY 0x01
+
+/** @} */
+
+struct spi_device;
+
+/**
+ * An SPI device type
+ *
+ * This data structure represents all the characteristics belonging to
+ * a particular type of SPI device, e.g. "an Atmel 251024 serial flash",
+ * or "a Microchip 25040 serial EEPROM".
+ */
+struct spi_device_type {
+ /** Word length, in bits */
+ unsigned int word_len;
+ /** Device size (in words) */
+ unsigned int size;
+ /** Data block size (in words)
+ *
+ * This is the block size used by the device. It must be a
+ * power of two. Data reads and writes must not cross a block
+ * boundary.
+ *
+ * Many devices allow reads to cross a block boundary, and
+ * restrict only writes. For the sake of simplicity, we
+ * assume that the same restriction applies to both reads and
+ * writes.
+ */
+ unsigned int block_size;
+ /** Command length, in bits */
+ unsigned int command_len;
+ /** Address length, in bits */
+ unsigned int address_len;
+ /** Address is munged
+ *
+ * Some devices with 9-bit addresses (e.g. AT25040A EEPROM)
+ * use bit 3 of the command byte as address bit A8, rather
+ * than having a two-byte address. If this flag is set, then
+ * commands should be munged in this way.
+ */
+ unsigned int munge_address : 1;
+ /** Read data from device
+ *
+ * @v device SPI device
+ * @v address Address from which to read
+ * @v data Data buffer
+ * @v len Length of data buffer
+ * @ret rc Return status code
+ */
+ int ( * read ) ( struct spi_device *device, unsigned int address,
+ void *data, size_t len );
+ /** Write data to device
+ *
+ * @v device SPI device
+ * @v address Address to which to write
+ * @v data Data buffer
+ * @v len Length of data buffer
+ * @ret rc Return status code
+ */
+ int ( * write ) ( struct spi_device *device, unsigned int address,
+ const void *data, size_t len );
+};
+
+/**
+ * @defgroup spidevs SPI device types
+ * @{
+ */
+
+/** Atmel AT25010 serial EEPROM */
+#define AT25010 { \
+ .word_len = 8, \
+ .size = 128, \
+ .block_size = 8, \
+ .command_len = 8, \
+ .address_len = 8, \
+ }
+
+/** @} */
+
+/**
+ * An SPI device
+ *
+ * This data structure represents a real, physical SPI device attached
+ * to an SPI controller. It comprises the device type plus
+ * instantiation-specific information such as the slave number.
+ */
+struct spi_device {
+ /** SPI device type */
+ struct spi_device_type *type;
+ /** SPI bus to which device is attached */
+ struct spi_bus *bus;
+ /** Slave number */
+ unsigned int slave;
+};
+
+/**
+ * An SPI bus
+ *
+ *
+ */
+struct spi_bus {
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