diff options
Diffstat (limited to 'gpxe/src/drivers/bitbash')
| -rw-r--r-- | gpxe/src/drivers/bitbash/bitbash.c | 57 | ||||
| -rw-r--r-- | gpxe/src/drivers/bitbash/i2c_bit.c | 393 | ||||
| -rw-r--r-- | gpxe/src/drivers/bitbash/spi_bit.c | 225 |
3 files changed, 0 insertions, 675 deletions
diff --git a/gpxe/src/drivers/bitbash/bitbash.c b/gpxe/src/drivers/bitbash/bitbash.c deleted file mode 100644 index 3e558d5c..00000000 --- a/gpxe/src/drivers/bitbash/bitbash.c +++ /dev/null @@ -1,57 +0,0 @@ -/* - * 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. - */ - -FILE_LICENCE ( GPL2_OR_LATER ); - -#include <gpxe/bitbash.h> - -/** @file - * - * Bit-bashing interfaces - * - */ - -/** - * Set/clear output bit - * - * @v basher Bit-bashing interface - * @v bit_id Bit number - * @v data Value to write - * - * If @c data is 0, a logic 0 will be written. If @c data is - * non-zero, a logic 1 will be written. - */ -void write_bit ( struct bit_basher *basher, unsigned int bit_id, - unsigned long data ) { - basher->op->write ( basher, bit_id, ( data ? -1UL : 0 ) ); -} - -/** - * Read input bit - * - * @v basher Bit-bashing interface - * @v bit_id Bit number - * @ret data Value read - * - * @c data will always be either 0 or -1UL. The idea is that the - * caller can simply binary-AND the returned value with whatever mask - * it needs to apply. - */ -int read_bit ( struct bit_basher *basher, unsigned int bit_id ) { - return ( basher->op->read ( basher, bit_id ) ? -1UL : 0 ); -} diff --git a/gpxe/src/drivers/bitbash/i2c_bit.c b/gpxe/src/drivers/bitbash/i2c_bit.c deleted file mode 100644 index 13197270..00000000 --- a/gpxe/src/drivers/bitbash/i2c_bit.c +++ /dev/null @@ -1,393 +0,0 @@ -/* - * 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. - */ - -FILE_LICENCE ( GPL2_OR_LATER ); - -#include <stddef.h> -#include <stdint.h> -#include <errno.h> -#include <string.h> -#include <assert.h> -#include <unistd.h> -#include <gpxe/bitbash.h> -#include <gpxe/i2c.h> - -/** @file - * - * I2C bit-bashing interface - * - * This implements a simple I2C master via a bit-bashing interface - * that provides two lines: SCL (clock) and SDA (data). - */ - -/** - * Delay between output state changes - * - * Max rated i2c speed (for the basic i2c protocol) is 100kbps, - * i.e. 200k clock transitions per second. - */ -static void i2c_delay ( void ) { - udelay ( I2C_UDELAY ); -} - -/** - * Set state of I2C SCL line - * - * @v basher Bit-bashing interface - * @v state New state of SCL - */ -static void setscl ( struct bit_basher *basher, int state ) { - DBG2 ( "%c", ( state ? '/' : '\\' ) ); - write_bit ( basher, I2C_BIT_SCL, state ); - i2c_delay(); -} - -/** - * Set state of I2C SDA line - * - * @v basher Bit-bashing interface - * @v state New state of SDA - */ -static void setsda ( struct bit_basher *basher, int state ) { - DBG2 ( "%c", ( state ? '1' : '0' ) ); - write_bit ( basher, I2C_BIT_SDA, state ); - i2c_delay(); -} - -/** - * Get state of I2C SDA line - * - * @v basher Bit-bashing interface - * @ret state State of SDA - */ -static int getsda ( struct bit_basher *basher ) { - int state; - state = read_bit ( basher, I2C_BIT_SDA ); - DBG2 ( "%c", ( state ? '+' : '-' ) ); - return state; -} - -/** - * Send an I2C start condition - * - * @v basher Bit-bashing interface - */ -static void i2c_start ( struct bit_basher *basher ) { - setscl ( basher, 1 ); - setsda ( basher, 0 ); - setscl ( basher, 0 ); - setsda ( basher, 1 ); -} - -/** - * Send an I2C data bit - * - * @v basher Bit-bashing interface - * @v bit Bit to send - */ -static void i2c_send_bit ( struct bit_basher *basher, int bit ) { - setsda ( basher, bit ); - setscl ( basher, 1 ); - setscl ( basher, 0 ); - setsda ( basher, 1 ); -} - -/** - * Receive an I2C data bit - * - * @v basher Bit-bashing interface - * @ret bit Received bit - */ -static int i2c_recv_bit ( struct bit_basher *basher ) { - int bit; - - setscl ( basher, 1 ); - bit = getsda ( basher ); - setscl ( basher, 0 ); - return bit; -} - -/** - * Send an I2C stop condition - * - * @v basher Bit-bashing interface - */ -static void i2c_stop ( struct bit_basher *basher ) { - setsda ( basher, 0 ); - setscl ( basher, 1 ); - setsda ( basher, 1 ); -} - -/** - * Send byte via I2C bus and check for acknowledgement - * - * @v basher Bit-bashing interface - * @v byte Byte to send - * @ret rc Return status code - * - * Sends a byte via the I2C bus and checks for an acknowledgement from - * the slave device. - */ -static int i2c_send_byte ( struct bit_basher *basher, uint8_t byte ) { - int i; - int ack; - - /* Send byte */ - DBG2 ( "[send %02x]", byte ); - for ( i = 8 ; i ; i-- ) { - i2c_send_bit ( basher, byte & 0x80 ); - byte <<= 1; - } - - /* Check for acknowledgement from slave */ - ack = ( i2c_recv_bit ( basher ) == 0 ); - DBG2 ( "%s", ( ack ? "[acked]" : "[not acked]" ) ); - - return ( ack ? 0 : -EIO ); -} - -/** - * Receive byte via I2C bus - * - * @v basher Bit-bashing interface - * @ret byte Received byte - * - * Receives a byte via the I2C bus and sends NACK to the slave device. - */ -static uint8_t i2c_recv_byte ( struct bit_basher *basher ) { - uint8_t byte = 0; - int i; - - /* Receive byte */ - for ( i = 8 ; i ; i-- ) { - byte <<= 1; - byte |= ( i2c_recv_bit ( basher ) & 0x1 ); - } - - /* Send NACK */ - i2c_send_bit ( basher, 1 ); - - DBG2 ( "[rcvd %02x]", byte ); - return byte; -} - -/** - * Select I2C device for reading or writing - * - * @v basher Bit-bashing interface - * @v i2cdev I2C device - * @v offset Starting offset within the device - * @v direction I2C_READ or I2C_WRITE - * @ret rc Return status code - */ -static int i2c_select ( struct bit_basher *basher, struct i2c_device *i2cdev, - unsigned int offset, unsigned int direction ) { - unsigned int address; - int shift; - unsigned int byte; - int rc; - - i2c_start ( basher ); - - /* Calculate address to appear on bus */ - address = ( ( ( i2cdev->dev_addr | - ( offset >> ( 8 * i2cdev->word_addr_len ) ) ) << 1 ) - | direction ); - - /* Send address a byte at a time */ - for ( shift = ( 8 * ( i2cdev->dev_addr_len - 1 ) ) ; - shift >= 0 ; shift -= 8 ) { - byte = ( ( address >> shift ) & 0xff ); - if ( ( rc = i2c_send_byte ( basher, byte ) ) != 0 ) - return rc; - } - - return 0; -} - -/** - * Reset I2C bus - * - * @v basher Bit-bashing interface - * @ret rc Return status code - * - * i2c devices often don't have a reset line, so even a reboot or - * system power cycle is sometimes not enough to bring them back to a - * known state. - */ -static int i2c_reset ( struct bit_basher *basher ) { - unsigned int i; - int sda; - - /* Clock through several cycles, waiting for an opportunity to - * pull SDA low while SCL is high (which creates a start - * condition). - */ - setscl ( basher, 0 ); - setsda ( basher, 1 ); - for ( i = 0 ; i < I2C_RESET_MAX_CYCLES ; i++ ) { - setscl ( basher, 1 ); - sda = getsda ( basher ); - if ( sda ) { - /* Now that the device will see a start, issue it */ - i2c_start ( basher ); - /* Stop the bus to leave it in a known good state */ - i2c_stop ( basher ); - DBGC ( basher, "I2CBIT %p reset after %d attempts\n", - basher, ( i + 1 ) ); - return 0; - } - setscl ( basher, 0 ); - } - - DBGC ( basher, "I2CBIT %p could not reset after %d attempts\n", - basher, i ); - return -ETIMEDOUT; -} - -/** - * Read data from I2C device via bit-bashing interface - * - * @v i2c I2C interface - * @v i2cdev I2C device - * @v offset Starting offset within the device - * @v data Data buffer - * @v len Length of data buffer - * @ret rc Return status code - * - * Note that attempting to read zero bytes of data is a valid way to - * check for I2C device presence. - */ -static int i2c_bit_read ( struct i2c_interface *i2c, - struct i2c_device *i2cdev, unsigned int offset, - uint8_t *data, unsigned int len ) { - struct i2c_bit_basher *i2cbit - = container_of ( i2c, struct i2c_bit_basher, i2c ); - struct bit_basher *basher = &i2cbit->basher; - int rc = 0; - - DBGC ( basher, "I2CBIT %p reading from device %x: ", - basher, i2cdev->dev_addr ); - - for ( ; ; data++, offset++ ) { - - /* Select device for writing */ - if ( ( rc = i2c_select ( basher, i2cdev, offset, - I2C_WRITE ) ) != 0 ) - break; - - /* Abort at end of data */ - if ( ! ( len-- ) ) - break; - - /* Select offset */ - if ( ( rc = i2c_send_byte ( basher, offset ) ) != 0 ) - break; - - /* Select device for reading */ - if ( ( rc = i2c_select ( basher, i2cdev, offset, - I2C_READ ) ) != 0 ) - break; - - /* Read byte */ - *data = i2c_recv_byte ( basher ); - DBGC ( basher, "%02x ", *data ); - } - - DBGC ( basher, "%s\n", ( rc ? "failed" : "" ) ); - i2c_stop ( basher ); - return rc; -} - -/** - * Write data to I2C device via bit-bashing interface - * - * @v i2c I2C interface - * @v i2cdev I2C device - * @v offset Starting offset within the device - * @v data Data buffer - * @v len Length of data buffer - * @ret rc Return status code - * - * Note that attempting to write zero bytes of data is a valid way to - * check for I2C device presence. - */ -static int i2c_bit_write ( struct i2c_interface *i2c, - struct i2c_device *i2cdev, unsigned int offset, - const uint8_t *data, unsigned int len ) { - struct i2c_bit_basher *i2cbit - = container_of ( i2c, struct i2c_bit_basher, i2c ); - struct bit_basher *basher = &i2cbit->basher; - int rc = 0; - - DBGC ( basher, "I2CBIT %p writing to device %x: ", - basher, i2cdev->dev_addr ); - - for ( ; ; data++, offset++ ) { - - /* Select device for writing */ - if ( ( rc = i2c_select ( basher, i2cdev, offset, - I2C_WRITE ) ) != 0 ) - break; - - /* Abort at end of data */ - if ( ! ( len-- ) ) - break; - - /* Select offset */ - if ( ( rc = i2c_send_byte ( basher, offset ) ) != 0 ) - break; - - /* Write data to device */ - DBGC ( basher, "%02x ", *data ); - if ( ( rc = i2c_send_byte ( basher, *data ) ) != 0 ) - break; - } - - DBGC ( basher, "%s\n", ( rc ? "failed" : "" ) ); - i2c_stop ( basher ); - return rc; -} - -/** - * Initialise I2C bit-bashing interface - * - * @v i2cbit I2C bit-bashing interface - * @v bash_op Bit-basher operations - */ -int init_i2c_bit_basher ( struct i2c_bit_basher *i2cbit, - struct bit_basher_operations *bash_op ) { - struct bit_basher *basher = &i2cbit->basher; - int rc; - - /* Initialise data structures */ - basher->op = bash_op; - assert ( basher->op->read != NULL ); - assert ( basher->op->write != NULL ); - i2cbit->i2c.read = i2c_bit_read; - i2cbit->i2c.write = i2c_bit_write; - - /* Reset I2C bus */ - if ( ( rc = i2c_reset ( basher ) ) != 0 ) { - DBGC ( basher, "I2CBIT %p could not reset I2C bus: %s\n", - basher, strerror ( rc ) ); - return rc; - } - - return 0; -} diff --git a/gpxe/src/drivers/bitbash/spi_bit.c b/gpxe/src/drivers/bitbash/spi_bit.c deleted file mode 100644 index 8e703936..00000000 --- a/gpxe/src/drivers/bitbash/spi_bit.c +++ /dev/null @@ -1,225 +0,0 @@ -/* - * 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. - */ - -FILE_LICENCE ( GPL2_OR_LATER ); - -#include <stddef.h> -#include <stdint.h> -#include <string.h> -#include <byteswap.h> -#include <errno.h> -#include <assert.h> -#include <unistd.h> -#include <gpxe/bitbash.h> -#include <gpxe/spi_bit.h> - -/** @file - * - * SPI bit-bashing interface - * - */ - -/** Delay between SCLK changes and around SS changes */ -static void spi_bit_delay ( void ) { - udelay ( SPI_BIT_UDELAY ); -} - -/** Chip select line will be asserted */ -#define SELECT_SLAVE 0 - -/** Chip select line will be deasserted */ -#define DESELECT_SLAVE SPI_MODE_SSPOL - -/** - * Select/deselect slave - * - * @v spibit SPI bit-bashing interface - * @v slave Slave number - * @v state Slave select state - * - * @c state must be @c SELECT_SLAVE or @c DESELECT_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->bus.mode & SPI_MODE_SSPOL ); - DBGC2 ( spibit, "SPIBIT %p setting slave %d select %s\n", - spibit, slave, ( state ? "high" : "low" ) ); - - spi_bit_delay(); - write_bit ( basher, SPI_BIT_SS ( slave ), state ); - spi_bit_delay(); -} - -/** - * Transfer bits over SPI bit-bashing bus - * - * @v bus SPI bus - * @v data_out TX data buffer (or NULL) - * @v data_in RX data buffer (or NULL) - * @v len Length of transfer (in @b bits) - * @v endianness Endianness of this data transfer - * - * 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_bit_basher *spibit, - const void *data_out, void *data_in, - unsigned int len, int endianness ) { - struct spi_bus *bus = &spibit->bus; - struct bit_basher *basher = &spibit->basher; - unsigned int sclk = ( ( bus->mode & SPI_MODE_CPOL ) ? 1 : 0 ); - unsigned int cpha = ( ( bus->mode & SPI_MODE_CPHA ) ? 1 : 0 ); - unsigned int bit_offset; - unsigned int byte_offset; - unsigned int byte_mask; - unsigned int bit; - unsigned int step; - - DBGC2 ( spibit, "SPIBIT %p transferring %d bits in mode %#x\n", - spibit, len, bus->mode ); - - for ( step = 0 ; step < ( len * 2 ) ; step++ ) { - /* Calculate byte offset and byte mask */ - bit_offset = ( ( endianness == SPI_BIT_BIG_ENDIAN ) ? - ( len - ( step / 2 ) - 1 ) : ( step / 2 ) ); - byte_offset = ( bit_offset / 8 ); - byte_mask = ( 1 << ( bit_offset % 8 ) ); - - /* Shift data in or out */ - if ( sclk == cpha ) { - const uint8_t *byte; - - /* Shift data out */ - if ( data_out ) { - byte = ( data_out + byte_offset ); - bit = ( *byte & byte_mask ); - DBGCP ( spibit, "SPIBIT %p wrote bit %d\n", - spibit, ( bit ? 1 : 0 ) ); - } 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 ) { - DBGCP ( spibit, "SPIBIT %p read bit %d\n", - spibit, ( bit ? 1 : 0 ) ); - byte = ( data_in + byte_offset ); - *byte &= ~byte_mask; - *byte |= ( bit & byte_mask ); - } - } - - /* Toggle clock line */ - spi_bit_delay(); - sclk ^= 1; - write_bit ( basher, SPI_BIT_SCLK, sclk ); - } -} - -/** - * Read/write data via SPI bit-bashing bus - * - * @v bus SPI bus - * @v device SPI device - * @v command Command - * @v address Address to read/write (<0 for no address) - * @v data_out TX data buffer (or NULL) - * @v data_in RX data buffer (or NULL) - * @v len Length of transfer - * @ret rc Return status code - */ -static int spi_bit_rw ( struct spi_bus *bus, struct spi_device *device, - unsigned int command, int address, - const void *data_out, void *data_in, size_t len ) { - struct spi_bit_basher *spibit - = container_of ( bus, struct spi_bit_basher, bus ); - uint32_t tmp_command; - uint32_t tmp_address; - uint32_t tmp_address_detect; - - /* Set clock line to idle state */ - write_bit ( &spibit->basher, SPI_BIT_SCLK, - ( bus->mode & SPI_MODE_CPOL ) ); - - /* Assert chip select on specified slave */ - spi_bit_set_slave_select ( spibit, device->slave, SELECT_SLAVE ); - - /* Transmit command */ - assert ( device->command_len <= ( 8 * sizeof ( tmp_command ) ) ); - tmp_command = cpu_to_le32 ( command ); - spi_bit_transfer ( spibit, &tmp_command, NULL, device->command_len, - SPI_BIT_BIG_ENDIAN ); - - /* Transmit address, if present */ - if ( address >= 0 ) { - assert ( device->address_len <= ( 8 * sizeof ( tmp_address ))); - tmp_address = cpu_to_le32 ( address ); - if ( device->address_len == SPI_AUTODETECT_ADDRESS_LEN ) { - /* Autodetect address length. This relies on - * the device responding with a dummy zero - * data bit before the first real data bit. - */ - DBGC ( spibit, "SPIBIT %p autodetecting device " - "address length\n", spibit ); - assert ( address == 0 ); - device->address_len = 0; - do { - spi_bit_transfer ( spibit, &tmp_address, - &tmp_address_detect, 1, - SPI_BIT_BIG_ENDIAN ); - device->address_len++; - } while ( le32_to_cpu ( tmp_address_detect ) & 1 ); - DBGC ( spibit, "SPIBIT %p autodetected device address " - "length %d\n", spibit, device->address_len ); - } else { - spi_bit_transfer ( spibit, &tmp_address, NULL, - device->address_len, - SPI_BIT_BIG_ENDIAN ); - } - } - - /* Transmit/receive data */ - spi_bit_transfer ( spibit, data_out, data_in, ( len * 8 ), - spibit->endianness ); - - /* Deassert chip select on specified slave */ - spi_bit_set_slave_select ( spibit, device->slave, DESELECT_SLAVE ); - - return 0; -} - -/** - * Initialise SPI bit-bashing interface - * - * @v spibit SPI bit-bashing interface - */ -void init_spi_bit_basher ( struct spi_bit_basher *spibit ) { - assert ( &spibit->basher.op->read != NULL ); - assert ( &spibit->basher.op->write != NULL ); - spibit->bus.rw = spi_bit_rw; -} |