diff options
Diffstat (limited to 'gpxe/src/drivers/nvs/threewire.c')
-rw-r--r-- | gpxe/src/drivers/nvs/threewire.c | 88 |
1 files changed, 88 insertions, 0 deletions
diff --git a/gpxe/src/drivers/nvs/threewire.c b/gpxe/src/drivers/nvs/threewire.c new file mode 100644 index 00000000..dbecf909 --- /dev/null +++ b/gpxe/src/drivers/nvs/threewire.c @@ -0,0 +1,88 @@ +/* + * 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 <assert.h> +#include <unistd.h> +#include <gpxe/threewire.h> + +/** @file + * + * Three-wire serial devices + * + */ + +/** + * Read data from three-wire 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 threewire_read ( struct nvs_device *nvs, unsigned int address, + void *data, size_t len ) { + struct spi_device *device = nvs_to_spi ( nvs ); + struct spi_bus *bus = device->bus; + + assert ( bus->mode == SPI_MODE_THREEWIRE ); + + DBG ( "3wire %p reading %zd bytes at %04x\n", device, len, address ); + + return bus->rw ( bus, device, THREEWIRE_READ, address, + NULL, data, len ); +} + +/** + * Write data to three-wire 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 threewire_write ( struct nvs_device *nvs, unsigned int address, + const void *data, size_t len ) { + struct spi_device *device = nvs_to_spi ( nvs ); + struct spi_bus *bus = device->bus; + int rc; + + assert ( bus->mode == SPI_MODE_THREEWIRE ); + + DBG ( "3wire %p writing %zd bytes at %04x\n", device, len, address ); + + /* Enable device for writing */ + if ( ( rc = bus->rw ( bus, device, THREEWIRE_EWEN, + THREEWIRE_EWEN_ADDRESS, NULL, NULL, 0 ) ) != 0 ) + return rc; + + /* Write data */ + if ( ( rc = bus->rw ( bus, device, THREEWIRE_WRITE, address, + data, NULL, len ) ) != 0 ) + return rc; + + /* Our model of an SPI bus doesn't provide a mechanism for + * "assert CS, wait for MISO to become high, so just wait for + * long enough to ensure that the write has completed. + */ + mdelay ( THREEWIRE_WRITE_MDELAY ); + + return 0; +} |