mirror of
https://github.com/xcat2/xNBA.git
synced 2024-12-16 16:21:32 +00:00
139 lines
3.7 KiB
C
139 lines
3.7 KiB
C
/*
|
|
* 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 <errno.h>
|
|
#include <timer.h>
|
|
#include <gpxe/spi.h>
|
|
|
|
/** @file
|
|
*
|
|
* SPI devices
|
|
*
|
|
*/
|
|
|
|
/**
|
|
* Munge SPI device address into command
|
|
*
|
|
* @v command SPI command
|
|
* @v address Address
|
|
* @v munge_address Device requires address munging
|
|
* @ret command Actual SPI command to use
|
|
*
|
|
* Some devices with 9-bit addresses (e.g. AT25040A EEPROM) use bit 3
|
|
* of the command byte as address bit A8, rather than having a
|
|
* two-byte address. This function takes care of generating the
|
|
* appropriate command.
|
|
*/
|
|
static inline unsigned int spi_command ( unsigned int command,
|
|
unsigned int address,
|
|
int munge_address ) {
|
|
return ( command | ( ( ( address >> 8 ) & munge_address ) << 3 ) );
|
|
}
|
|
|
|
/**
|
|
* Wait for SPI device to complete operation
|
|
*
|
|
* @v device SPI device
|
|
* @ret rc Return status code
|
|
*/
|
|
static int spi_wait ( struct spi_device *device ) {
|
|
struct spi_bus *bus = device->bus;
|
|
uint8_t status;
|
|
int i;
|
|
int rc;
|
|
|
|
for ( i = 0 ; i < 50 ; i++ ) {
|
|
udelay ( 20 );
|
|
if ( ( rc = bus->rw ( bus, device, SPI_RDSR, -1, NULL,
|
|
&status, sizeof ( status ) ) ) != 0 )
|
|
return rc;
|
|
if ( ! ( status & SPI_STATUS_NRDY ) )
|
|
return 0;
|
|
}
|
|
DBG ( "SPI %p timed out\n", device );
|
|
return -ETIMEDOUT;
|
|
}
|
|
|
|
/**
|
|
* Read data from SPI device
|
|
*
|
|
* @v nvs NVS device
|
|
* @v address Address from which to read
|
|
* @v data Data buffer
|
|
* @v len Length of data buffer
|
|
* @ret rc Return status code
|
|
*/
|
|
int spi_read ( struct nvs_device *nvs, unsigned int address,
|
|
void *data, unsigned int len ) {
|
|
struct spi_device *device = nvs_to_spi ( nvs );
|
|
struct spi_bus *bus = device->bus;
|
|
unsigned int command = spi_command ( SPI_READ, address,
|
|
device->munge_address );
|
|
int rc;
|
|
|
|
DBG ( "SPI %p reading %d bytes from %#04x\n", device, len, address );
|
|
if ( ( rc = bus->rw ( bus, device, command, address,
|
|
NULL, data, len ) ) != 0 ) {
|
|
DBG ( "SPI %p failed to read data from device\n", device );
|
|
return rc;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* Write data to SPI device
|
|
*
|
|
* @v nvs NVS device
|
|
* @v address Address from which to read
|
|
* @v data Data buffer
|
|
* @v len Length of data buffer
|
|
* @ret rc Return status code
|
|
*/
|
|
int spi_write ( struct nvs_device *nvs, unsigned int address,
|
|
const void *data, unsigned int len ) {
|
|
struct spi_device *device = nvs_to_spi ( nvs );
|
|
struct spi_bus *bus = device->bus;
|
|
unsigned int command = spi_command ( SPI_WRITE, address,
|
|
device->munge_address );
|
|
int rc;
|
|
|
|
DBG ( "SPI %p writing %d bytes to %#04x\n", device, len, address );
|
|
|
|
if ( ( rc = bus->rw ( bus, device, SPI_WREN, -1,
|
|
NULL, NULL, 0 ) ) != 0 ) {
|
|
DBG ( "SPI %p failed to write-enable device\n", device );
|
|
return rc;
|
|
}
|
|
|
|
if ( ( rc = bus->rw ( bus, device, command, address,
|
|
data, NULL, len ) ) != 0 ) {
|
|
DBG ( "SPI %p failed to write data to device\n", device );
|
|
return rc;
|
|
}
|
|
|
|
if ( ( rc = spi_wait ( device ) ) != 0 ) {
|
|
DBG ( "SPI %p failed to complete write operation\n", device );
|
|
return rc;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|