Generalise three-wire interface to generic SPI interface.

Update rtl8139 driver to instantiate an SPI interface with a three-wire
device attached.

src/drivers/bitbash/spi_bit.c

@@ -0,0 +1,165 @@
+/*
+ * Copyright (C) 2006 Michael Brown <mbrown@fensystems.co.uk>.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or any later version.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
+ */
+
+#include <stddef.h>
+#include <stdint.h>
+#include <string.h>
+#include <errno.h>
+#include <assert.h>
+#include <timer.h>
+#include <gpxe/bitbash.h>
+#include <gpxe/spi.h>
+
+/** @file
+ *
+ * SPI bit-bashing interface
+ *
+ */
+
+/** Delay between SCLK changes and around SS changes */
+static void spi_delay ( void ) {
+	udelay ( SPI_UDELAY );
+}
+
+/**
+ * Select/deselect slave
+ *
+ * @v spi		SPI bit-bashing interface
+ * @v slave		Slave number
+ * @v state		Slave select state
+ *
+ * @c state must be set to zero to select the specified slave, or to
+ * @c SPI_MODE_SSPOL to deselect the slave.
+ */
+static void spi_bit_set_slave_select ( struct spi_bit_basher *spibit,
+				       unsigned int slave,
+				       unsigned int state ) {
+	struct bit_basher *basher = &spibit->basher;
+
+	state ^= ( spibit->spi.mode & SPI_MODE_SSPOL );
+	DBG ( "Setting slave %d select %s\n", slave,
+	      ( state ? "high" : "low" ) );
+
+	spi_delay();
+	write_bit ( basher, SPI_BIT_SS ( slave ), state );
+	spi_delay();
+}
+
+/**
+ * Select slave
+ *
+ * @v spi		SPI interface
+ * @v slave		Slave number
+ */
+static void spi_bit_select_slave ( struct spi_interface *spi,
+				   unsigned int slave ) {
+	struct spi_bit_basher *spibit
+		= container_of ( spi, struct spi_bit_basher, spi );
+
+	spibit->slave = slave;
+	spi_bit_set_slave_select ( spibit, slave, 0 );
+}
+
+/**
+ * Deselect slave
+ *
+ * @v spi		SPI interface
+ */
+static void spi_bit_deselect_slave ( struct spi_interface *spi ) {
+	struct spi_bit_basher *spibit
+		= container_of ( spi, struct spi_bit_basher, spi );
+
+	spi_bit_set_slave_select ( spibit, spibit->slave, SPI_MODE_SSPOL );
+}
+
+/**
+ * Transfer bits over SPI bit-bashing interface
+ *
+ * @v spi		SPI interface
+ * @v data_out		TX data buffer (or NULL)
+ * @v data_in		RX data buffer (or NULL)
+ * @v len		Length of transfer (in @b bits)
+ *
+ * This issues @c len clock cycles on the SPI bus, shifting out data
+ * from the @c data_out buffer to the MOSI line and shifting in data
+ * from the MISO line to the @c data_in buffer.  If @c data_out is
+ * NULL, then the data sent will be all zeroes.  If @c data_in is
+ * NULL, then the incoming data will be discarded.
+ */
+static void spi_bit_transfer ( struct spi_interface *spi, const void *data_out,
+			       void *data_in, unsigned int len ) {
+	struct spi_bit_basher *spibit
+		= container_of ( spi, struct spi_bit_basher, spi );
+	struct bit_basher *basher = &spibit->basher;
+	unsigned int sclk = ( ( spi->mode & SPI_MODE_CPOL ) ? 1 : 0 );
+	unsigned int cpha = ( ( spi->mode & SPI_MODE_CPHA ) ? 1 : 0 );
+	unsigned int offset;
+	unsigned int mask;
+	unsigned int bit;
+	int step;
+
+	DBG ( "Transferring %d bits in mode %x\n", len, spi->mode );
+
+	for ( step = ( ( len * 2 ) - 1 ) ; step >= 0 ; step-- ) {
+		/* Calculate byte offset within data and bit mask */
+		offset = ( step / 16 );
+		mask = ( 1 << ( ( step % 16 ) / 2 ) );
+		
+		/* Shift data in or out */
+		if ( sclk == cpha ) {
+			const uint8_t *byte;
+
+			/* Shift data out */
+			if ( data_out ) {
+				byte = ( data_out + offset );
+				bit = ( *byte & mask );
+			} else {
+				bit = 0;
+			}
+			write_bit ( basher, SPI_BIT_MOSI, bit );
+		} else {
+			uint8_t *byte;
+
+			/* Shift data in */
+			bit = read_bit ( basher, SPI_BIT_MISO );
+			if ( data_in ) {
+				byte = ( data_in + offset );
+				*byte &= ~mask;
+				*byte |= ( bit & mask );
+			}
+		}
+
+		/* Toggle clock line */
+		spi_delay();
+		sclk = ~sclk;
+		write_bit ( basher, SPI_BIT_SCLK, sclk );
+	}
+}
+
+/**
+ * Initialise SPI bit-bashing interface
+ *
+ * @v spibit		SPI bit-bashing interface
+ */
+void init_spi_bit_basher ( struct spi_bit_basher *spibit ) {
+	assert ( &spibit->basher.read != NULL );
+	assert ( &spibit->basher.write != NULL );
+	spibit->spi.select_slave = spi_bit_select_slave;
+	spibit->spi.deselect_slave = spi_bit_deselect_slave;
+	spibit->spi.transfer = spi_bit_transfer;
+}

src/drivers/net/rtl8139.c

@@ -77,7 +77,8 @@
 #include <gpxe/ethernet.h>
 #include <gpxe/pkbuff.h>
 #include <gpxe/netdevice.h>
-#include <gpxe/nvs/threewire.h>
+#include <gpxe/spi.h>
+#include <gpxe/threewire.h>
 
 #define TX_RING_SIZE 4
 
@@ -92,10 +93,11 @@ struct rtl8139_rx {
 };
 
 struct rtl8139_nic {
-	struct threewire eeprom;
 	unsigned short ioaddr;
 	struct rtl8139_tx tx;
 	struct rtl8139_rx rx;
+	struct spi_bit_basher spibit;
+	struct threewire_device eeprom;
 };
 
 /* Tuning Parameters */
@@ -192,8 +194,8 @@ enum RxConfigBits {
 };
 
 /*  EEPROM access */
-#define EE_MODE_PROGRAM	0x80
-#define EE_MODE_NORMAL	0x00
+#define EE_M1		0x80	/* Mode select bit 1 */
+#define EE_M0		0x40	/* Mode select bit 0 */
 #define EE_CS		0x08	/* EEPROM chip select */
 #define EE_SK		0x04	/* EEPROM shift clock */
 #define EE_DI		0x02	/* Data in */
@@ -202,51 +204,40 @@ enum RxConfigBits {
 /* Offsets within EEPROM (these are word offsets) */
 #define EE_MAC 7
 
-static inline struct rtl8139_nic * three_to_rtl ( struct threewire *three ) {
-	return container_of ( three, struct rtl8139_nic, eeprom );
+static inline struct rtl8139_nic *
+basher_to_rtl ( struct bit_basher *basher ) {
+	return container_of ( basher, struct rtl8139_nic, spibit.basher );
 }
 
-static void rtl_setcs ( struct threewire *three, int cs ) {
-	struct rtl8139_nic *rtl = three_to_rtl ( three );
-	unsigned int eereg;
-
-	eereg = cs ? ( EE_MODE_PROGRAM | EE_CS ) : ( EE_MODE_NORMAL );
-	outb ( eereg, rtl->ioaddr + Cfg9346 );
-}
+static const uint8_t rtl_ee_bits[] = {
+	[SPI_BIT_SCLK]	= EE_SK,
+	[SPI_BIT_MOSI]	= EE_DI,
+	[SPI_BIT_MISO]	= EE_DO,
+	[SPI_BIT_SS(0)]	= ( EE_CS | EE_M1 ),
+};
 
-static void rtl_setsk ( struct threewire *three, int sk ) {
-	struct rtl8139_nic *rtl = three_to_rtl ( three );
-	unsigned int eereg;
+static int rtl_spi_read_bit ( struct bit_basher *basher,
+			      unsigned int bit_id ) {
+	struct rtl8139_nic *rtl = basher_to_rtl ( basher );
+	uint8_t mask = rtl_ee_bits[bit_id];
+	uint8_t eereg;
 
 	eereg = inb ( rtl->ioaddr + Cfg9346 );
-	eereg = ( eereg & ~EE_SK ) | ( sk ? EE_SK : 0 );
-	outb ( eereg, rtl->ioaddr + Cfg9346 );
+	return ( eereg & mask );
 }
 
-static void rtl_setdi ( struct threewire *three, int di ) {
-	struct rtl8139_nic *rtl = three_to_rtl ( three );
-	unsigned int eereg;
+static void rtl_spi_write_bit ( struct bit_basher *basher,
+				unsigned int bit_id, unsigned long data ) {
+	struct rtl8139_nic *rtl = basher_to_rtl ( basher );
+	uint8_t mask = rtl_ee_bits[bit_id];
+	uint8_t eereg;
 
 	eereg = inb ( rtl->ioaddr + Cfg9346 );
-	eereg = ( eereg & ~EE_DI ) | ( di ? EE_DI : 0 );
+	eereg &= ~mask;
+	eereg |= ( data & mask );
 	outb ( eereg, rtl->ioaddr + Cfg9346 );
 }
 
-static int rtl_getdo ( struct threewire *three ) {
-	struct rtl8139_nic *rtl = three_to_rtl ( three );
-	unsigned int eereg;
-
-	eereg = ( inb ( rtl->ioaddr + Cfg9346 ) & EE_DO );
-	return eereg;
-}
-
-static struct threewire_operations rtl_three_ops = {
-	.setcs = rtl_setcs,
-	.setsk = rtl_setsk,
-	.setdi = rtl_setdi,
-	.getdo = rtl_getdo,
-};
-
 /**
  * Set up for EEPROM access
  *
@@ -255,14 +246,20 @@ static struct threewire_operations rtl_three_ops = {
 static void rtl_init_eeprom ( struct rtl8139_nic *rtl ) {
 	int ee9356;
 
+	/* Initialise three-wire bus */
+	rtl->spibit.basher.read = rtl_spi_read_bit;
+	rtl->spibit.basher.write = rtl_spi_write_bit;
+	rtl->spibit.spi.mode = SPI_MODE_THREEWIRE;
+	init_spi_bit_basher ( &rtl->spibit );
+
+	/* Detect EEPROM type and initialise three-wire device */
 	ee9356 = ( inw ( rtl->ioaddr + RxConfig ) & Eeprom9356 );
 	DBG ( "EEPROM is an %s\n", ee9356 ? "AT93C56" : "AT93C46" );
-	rtl->eeprom.ops = &rtl_three_ops;
 	rtl->eeprom.adrsize =
 		( ee9356 ? AT93C56_ORG16_ADRSIZE : AT93C46_ORG16_ADRSIZE );
 	rtl->eeprom.datasize =
 		( ee9356 ? AT93C56_ORG16_DATASIZE : AT93C46_ORG16_DATASIZE );
-	rtl->eeprom.udelay = 1;
+	rtl->eeprom.spi = &rtl->spibit.spi;
 }
 
 /**
@@ -279,9 +276,8 @@ static void rtl_read_mac ( struct rtl8139_nic *rtl, uint8_t *mac_addr ) {
 	int i;
 	
 	DBG ( "MAC address is " );
-	for ( i = 0 ; i < ( ETH_ALEN / 2 ) ; i++ ) {
-		u.word = cpu_to_le16 ( threewire_read ( &rtl->eeprom,
-							EE_MAC + i ) );
+	for ( i = EE_MAC ; i < ( EE_MAC + ( ETH_ALEN / 2 ) ) ; i++ ) {
+		u.word = cpu_to_le16 ( threewire_read ( &rtl->eeprom, i ) );
 		*mac_addr++ = u.bytes[0];
 		*mac_addr++ = u.bytes[1];
 		DBG ( "%02x%02x", u.bytes[0], u.bytes[1] );

src/drivers/nvs/threewire.c

@@ -16,53 +16,42 @@
  * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
  */
 
-#include <timer.h>
-#include <gpxe/nvs/threewire.h>
+#include <stddef.h>
+#include <byteswap.h>
+#include <gpxe/spi.h>
+#include <gpxe/threewire.h>
 
 /** @file
  *
- * Three-wire serial interface
+ * Three-wire serial devices
  *
  */
 
 /**
  * Read from a three-wire device
  *
- * @v three	Three-wire interface
+ * @v three	Three-wire device
  * @v address	Address
  * @ret data	Data
  */
-unsigned long threewire_read ( struct threewire *three,
+unsigned long threewire_read ( struct threewire_device *three,
 			       unsigned long address ) {
-	struct threewire_operations *ops = three->ops;
-	unsigned long command;
-	unsigned long data;
-	int i;
+	struct spi_interface *spi = three->spi;
+	uint32_t data;
 
-	ops->setcs ( three, 1 );
-	
-	/* Send command and address */
-	command = threewire_cmd_read ( three, address );
-	for ( i = ( threewire_cmd_len ( three ) - 1 ) ; i >= 0 ; i-- ) {
-		ops->setdi ( three, ( command >> i ) & 0x1 );
-		udelay ( three->udelay );
-		ops->setsk ( three, 1 );
-		udelay ( three->udelay );
-		ops->setsk ( three, 0 );
-	}
+	/* Activate chip select line */
+	spi->select_slave ( spi, three->slave );
 
+	/* Send command and address */
+	data = cpu_to_le32 ( threewire_cmd_read ( three, address ) );
+	spi->transfer ( spi, &data, NULL, threewire_cmd_len ( three ) );
+	
 	/* Read back data */
 	data = 0;
-	for ( i = three->datasize ; i ; i-- ) {
-		udelay ( three->udelay );
-		ops->setsk ( three, 1 );
-		udelay ( three->udelay );
-		data <<= 1;
-		data |= ops->getdo ( three );
-		ops->setsk ( three, 0 );
-	}
+	spi->transfer ( spi, NULL, &data, three->datasize );
 
-	ops->setcs ( three, 0 );
+	/* Deactivate chip select line */
+	spi->deselect_slave ( spi );
 
-	return data;
+	return le32_to_cpu ( data );;
 }

src/include/gpxe/nvs/threewire.h

@@ -1,102 +0,0 @@
-#ifndef _GPXE_NVS_THREEWIRE_H
-#define _GPXE_NVS_THREEWIRE_H
-
-/** @file
- *
- * Three-wire serial interface
- *
- */
-
-struct threewire;
-
-/** Three-wire interface methods */
-struct threewire_operations {
-	/**
-	 * Set status of Chip Select line
-	 *
-	 * @v three	Three-wire interface
-	 * @v cs	New status for chip select line
-	 */
-	void ( * setcs ) ( struct threewire *three, int cs );
-	/**
-	 * Set status of Serial Clock line
-	 *
-	 * @v three	Three-wire interface
-	 * @v sk	New status for serial clock line
-	 */
-	void ( * setsk ) ( struct threewire *three, int sk );
-	/**
-	 * Set status of Data Input line
-	 *
-	 * @v three	Three-wire interface
-	 * @v di	New status for data input line
-	 */
-	void ( * setdi ) ( struct threewire *three, int di );
-	/**
-	 * Get status of Data Output line
-	 *
-	 * @v three	Three-wire interface
-	 * @ret do	Status of data output line
-	 */
-	int ( * getdo ) ( struct threewire *three );
-};
-
-/**
- * A three-wire serial interface
- *
- * This interface consists of a clock line (SK), data input (DI) and
- * data output (DO).  There is also a chip select line (CS) which is
- * integral to the operation of the device, but Atmel still calls it a
- * three-wire interface.
- *
- */
-struct threewire {
-	/** Interface methods */
-	struct threewire_operations *ops;
-	/** Address size (in bits) */
-	unsigned int adrsize;
-	/** Data size (in bits) */
-	unsigned int datasize;
-	/** Delay between SK transitions (in us) */
-	unsigned int udelay;
-};
-
-/**
- * Calculate read command for a specified address
- *
- * @v three	Three-wire interface
- * @v address	Address
- * @ret cmd	Command
- */
-static inline __attribute__ (( always_inline )) unsigned long
-threewire_cmd_read ( struct threewire *three, unsigned long address ) {
-	return ( ( 0x6 << three->adrsize ) | address );
-}
-
-/**
- * Calculate command length
- *
- * @v three	Three-wire interface
- * @ret len	Command length, in bits
- */
-static inline __attribute__ (( always_inline )) int
-threewire_cmd_len ( struct threewire *three ) {
-	return ( three->adrsize + 3 );
-}
-
-/* Constants for some standard parts */
-#define AT93C46_ORG8_ADRSIZE	7
-#define AT93C46_ORG8_DATASIZE	8
-#define AT93C46_ORG16_ADRSIZE	6
-#define AT93C46_ORG16_DATASIZE	16
-#define AT93C46_UDELAY		1
-#define AT93C56_ORG8_ADRSIZE	9
-#define AT93C56_ORG8_DATASIZE	8
-#define AT93C56_ORG16_ADRSIZE	8
-#define AT93C56_ORG16_DATASIZE	16
-#define AT93C56_UDELAY		1
-
-extern unsigned long threewire_read ( struct threewire *three,
-				      unsigned long address );
-
-#endif /* _GPXE_NVS_THREEWIRE_H */

src/include/gpxe/spi.h

@@ -0,0 +1,132 @@
+#ifndef _GPXE_SPI_H
+#define _GPXE_SPI_H
+
+/** @file
+ *
+ * SPI interface
+ *
+ */
+
+#include <gpxe/bitbash.h>
+
+/** An SPI interface */
+struct spi_interface {
+	/** SPI interface mode
+	 *
+	 * This is the bitwise OR of zero or more of @c SPI_MODE_CPHA
+	 * and @c SPI_MODE_CPOL.  It is also the number conventionally
+	 * used to describe the SPI interface mode.  For example, SPI
+	 * mode 1 is the mode in which CPOL=0 and CPHA=1, which
+	 * therefore corresponds to a mode value of (0|SPI_MODE_CPHA)
+	 * which, happily, equals 1.
+	 */
+	unsigned int mode;
+	/**
+	 * Select slave
+	 *
+	 * @v spi		SPI interface
+	 * @v slave		Slave number
+	 */
+	void ( * select_slave ) ( struct spi_interface *spi,
+				  unsigned int slave );
+	/**
+	 * Deselect slave
+	 *
+	 * @v spi		SPI interface
+	 */
+	void ( * deselect_slave ) ( struct spi_interface *spi );
+	/**
+	 * Transfer bits over SPI bit-bashing interface
+	 *
+	 * @v spi		SPI interface
+	 * @v data_out		TX data buffer (or NULL)
+	 * @v data_in		RX data buffer (or NULL)
+	 * @v len		Length of transfer (in @b bits)
+	 */
+	void ( * transfer ) ( struct spi_interface *spi, const void *data_out,
+			      void *data_in, unsigned int len );
+};
+
+/** Clock phase (CPHA) mode bit
+ *
+ * Phase 0 is sample on rising edge, shift data on falling edge.
+ *
+ * Phase 1 is shift data on rising edge, sample data on falling edge.
+ */
+#define SPI_MODE_CPHA 0x01
+
+/** Clock polarity (CPOL) mode bit
+ *
+ * This bit reflects the idle state of the clock line (SCLK).
+ */
+#define SPI_MODE_CPOL 0x02
+
+/** Slave select polarity mode bit
+ *
+ * This bit reflects that active state of the slave select lines.  It
+ * is not part of the normal SPI mode number (which covers only @c
+ * SPI_MODE_CPOL and @c SPI_MODE_CPHA), but is included here for
+ * convenience.
+ */
+#define SPI_MODE_SSPOL 0x10
+
+/** Microwire-compatible mode
+ *
+ * This is SPI mode 1 (i.e. CPOL=0, CPHA=1), and is compatible with
+ * the original Microwire protocol.
+ */
+#define SPI_MODE_MICROWIRE 1
+
+/** Microwire/Plus-compatible mode
+ *
+ * This is SPI mode 0 (i.e. CPOL=0, CPHA=0), and is compatible with
+ * the Microwire/Plus protocol
+ */
+#define SPI_MODE_MICROWIRE_PLUS 0
+
+/** Threewire-compatible mode
+ *
+ * This mode is compatible with Atmel's series of "three-wire"
+ * interfaces.
+ */
+#define SPI_MODE_THREEWIRE ( SPI_MODE_MICROWIRE_PLUS | SPI_MODE_SSPOL )
+
+/** A bit-bashing SPI interface */
+struct spi_bit_basher {
+	/** SPI interface */
+	struct spi_interface spi;
+	/** Bit-bashing interface */
+	struct bit_basher basher;
+	/** Currently selected slave
+	 *
+	 * Valid only when a slave is actually selected.
+	 */
+	unsigned int slave;
+};
+
+/** Bit indices used for SPI bit-bashing interface */
+enum {
+	/** Serial clock */
+	SPI_BIT_SCLK = 0,
+	/** Master Out Slave In */
+	SPI_BIT_MOSI,
+	/** Master In Slave Out */
+	SPI_BIT_MISO,
+	/** Slave 0 select */
+	SPI_BIT_SS0,
+};
+
+/**
+ * Determine bit index for a particular slave
+ *
+ * @v slave		Slave number
+ * @ret index		Bit index (i.e. SPI_BIT_SSN, where N=slave) 
+ */
+#define SPI_BIT_SS( slave ) ( SPI_BIT_SS0 + (slave) )
+
+/** Delay between SCLK transitions */
+#define SPI_UDELAY 1
+
+extern void init_spi_bit_basher ( struct spi_bit_basher *spibit );
+
+#endif /* _GPXE_SPI_H */

src/include/gpxe/threewire.h

@@ -0,0 +1,65 @@
+#ifndef _GPXE_THREEWIRE_H
+#define _GPXE_THREEWIRE_H
+
+/** @file
+ *
+ * Three-wire serial interface
+ *
+ * The Atmel three-wire interface is a subset of the (newer) SPI
+ * interface, and is implemented here as a layer on top of the SPI
+ * support.
+ */
+
+struct spi_interface;
+
+/** A three-wire device */
+struct threewire_device {
+	/** SPI interface to which device is attached */
+	struct spi_interface *spi;
+	/** SPI slave number */
+	unsigned int slave;
+	/** Address size (in bits) */
+	unsigned int adrsize;
+	/** Data size (in bits) */
+	unsigned int datasize;
+};
+
+/**
+ * Calculate read command for a specified address
+ *
+ * @v three	Three-wire interface
+ * @v address	Address
+ * @ret cmd	Command
+ */
+static inline __attribute__ (( always_inline )) unsigned long
+threewire_cmd_read ( struct threewire_device *three, unsigned long address ) {
+	return ( ( 0x6 << three->adrsize ) | address );
+}
+
+/**
+ * Calculate command length
+ *
+ * @v three	Three-wire interface
+ * @ret len	Command length, in bits
+ */
+static inline __attribute__ (( always_inline )) unsigned int
+threewire_cmd_len ( struct threewire_device *three ) {
+	return ( three->adrsize + 3 );
+}
+
+/* Constants for some standard parts */
+#define AT93C46_ORG8_ADRSIZE	7
+#define AT93C46_ORG8_DATASIZE	8
+#define AT93C46_ORG16_ADRSIZE	6
+#define AT93C46_ORG16_DATASIZE	16
+#define AT93C46_UDELAY		1
+#define AT93C56_ORG8_ADRSIZE	9
+#define AT93C56_ORG8_DATASIZE	8
+#define AT93C56_ORG16_ADRSIZE	8
+#define AT93C56_ORG16_DATASIZE	16
+#define AT93C56_UDELAY		1
+
+extern unsigned long threewire_read ( struct threewire_device *three,
+				      unsigned long address );
+
+#endif /* _GPXE_THREEWIRE_H */