diff options
Diffstat (limited to 'qemu/roms/ipxe/src/drivers/bitbash/i2c_bit.c')
-rw-r--r-- | qemu/roms/ipxe/src/drivers/bitbash/i2c_bit.c | 407 |
1 files changed, 0 insertions, 407 deletions
diff --git a/qemu/roms/ipxe/src/drivers/bitbash/i2c_bit.c b/qemu/roms/ipxe/src/drivers/bitbash/i2c_bit.c deleted file mode 100644 index 707d9447d..000000000 --- a/qemu/roms/ipxe/src/drivers/bitbash/i2c_bit.c +++ /dev/null @@ -1,407 +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., 51 Franklin Street, Fifth Floor, Boston, MA - * 02110-1301, USA. - * - * You can also choose to distribute this program under the terms of - * the Unmodified Binary Distribution Licence (as given in the file - * COPYING.UBDL), provided that you have satisfied its requirements. - */ - -FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL ); - -#include <stddef.h> -#include <stdint.h> -#include <errno.h> -#include <string.h> -#include <assert.h> -#include <unistd.h> -#include <ipxe/bitbash.h> -#include <ipxe/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). - */ - open_bit ( basher ); - 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 ) ); - close_bit ( basher ); - return 0; - } - setscl ( basher, 0 ); - } - - DBGC ( basher, "I2CBIT %p could not reset after %d attempts\n", - basher, i ); - close_bit ( basher ); - 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 ); - - open_bit ( basher ); - - 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 ); - close_bit ( 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 ); - - open_bit ( basher ); - - 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 ); - close_bit ( 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; -} |