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