From ca67b09c015d4af3ae3cce12aa72e60941dbb8b5 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 18:29:52 +0200 Subject: Adding debian version 2.06-13+deb12u1. Signed-off-by: Daniel Baumann --- .../disabled/gpxe/src/drivers/bitbash/i2c_bit.c | 393 +++++++++++++++++++++ 1 file changed, 393 insertions(+) create mode 100644 debian/grub-extras/disabled/gpxe/src/drivers/bitbash/i2c_bit.c (limited to 'debian/grub-extras/disabled/gpxe/src/drivers/bitbash/i2c_bit.c') diff --git a/debian/grub-extras/disabled/gpxe/src/drivers/bitbash/i2c_bit.c b/debian/grub-extras/disabled/gpxe/src/drivers/bitbash/i2c_bit.c new file mode 100644 index 0000000..1319727 --- /dev/null +++ b/debian/grub-extras/disabled/gpxe/src/drivers/bitbash/i2c_bit.c @@ -0,0 +1,393 @@ +/* + * Copyright (C) 2006 Michael Brown . + * + * 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 +#include +#include +#include +#include +#include +#include +#include + +/** @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; +} -- cgit v1.2.3