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/*
* wcxb SPI library
*
* Copyright (C) 2013 Digium, Inc.
*
* All rights reserved.
*
*/
/*
* See http://www.asterisk.org for more information about
* the Asterisk project. Please do not directly contact
* any of the maintainers of this project for assistance;
* the project provides a web site, mailing lists and IRC
* channels for your use.
*
* This program is free software, distributed under the terms of
* the GNU General Public License Version 2 as published by the
* Free Software Foundation. See the LICENSE file included with
* this program for more details.
*/
#include <linux/kernel.h>
#include <linux/list.h>
#include <linux/device.h>
#include <linux/sched.h>
#include "wcxb_spi.h"
#include "wcxb_flash.h"
#define FLASH_PAGE_PROGRAM 0x02
#define FLASH_READ 0x03
#define FLASH_READ_STATUS 0x05
#define FLASH_WRITE_ENABLE 0x06
#define FLASH_SECTOR_ERASE 0xd8
static int wcxb_flash_read_status_register(struct wcxb_spi_device *spi,
u8 *status)
{
u8 command[] = {
FLASH_READ_STATUS,
};
struct wcxb_spi_transfer t_cmd = {
.tx_buf = command,
.len = sizeof(command),
};
struct wcxb_spi_transfer t_serial = {
.rx_buf = status,
.len = 1,
};
struct wcxb_spi_message m;
wcxb_spi_message_init(&m);
wcxb_spi_message_add_tail(&t_cmd, &m);
wcxb_spi_message_add_tail(&t_serial, &m);
return wcxb_spi_sync(spi, &m);
}
int wcxb_flash_read(struct wcxb_spi_device *spi, unsigned int address,
void *data, size_t len)
{
u8 command[] = {
FLASH_READ,
(address & 0xff0000) >> 16,
(address & 0xff00) >> 8,
(address & 0xff)
};
struct wcxb_spi_transfer t_cmd = {
.tx_buf = command,
.len = sizeof(command),
};
struct wcxb_spi_transfer t_serial = {
.rx_buf = data,
.len = len,
};
struct wcxb_spi_message m;
wcxb_spi_message_init(&m);
wcxb_spi_message_add_tail(&t_cmd, &m);
wcxb_spi_message_add_tail(&t_serial, &m);
return wcxb_spi_sync(spi, &m);
}
static int wcxb_flash_wait_until_not_busy(struct wcxb_spi_device *spi)
{
int res;
u8 status;
unsigned long stop = jiffies + 5*HZ;
do {
res = wcxb_flash_read_status_register(spi, &status);
} while (!res && (status & 0x1) && time_before(jiffies, stop));
if (!res)
return res;
if (time_after_eq(jiffies, stop))
return -EIO;
return 0;
}
static int wcxb_flash_write_enable(struct wcxb_spi_device *spi)
{
u8 command = FLASH_WRITE_ENABLE;
return wcxb_spi_write(spi, &command, 1);
}
int wcxb_flash_sector_erase(struct wcxb_spi_device *spi,
unsigned int address)
{
int res;
u8 command[] = {FLASH_SECTOR_ERASE, (address >> 16)&0xff, 0x00, 0x00};
/* Sector must be on 64KB boundary. */
if (address & 0xffff)
return -EINVAL;
/* Start the erase. */
res = wcxb_flash_write_enable(spi);
if (res)
return res;
res = wcxb_spi_write(spi, &command, sizeof(command));
if (res)
return res;
return wcxb_flash_wait_until_not_busy(spi);
}
int wcxb_flash_write(struct wcxb_spi_device *spi, unsigned int address,
const void *data, size_t len)
{
int res;
const size_t FLASH_PAGE_SIZE = 256;
u8 command[] = {
FLASH_PAGE_PROGRAM,
(address & 0xff0000) >> 16,
(address & 0xff00) >> 8,
0x00,
};
struct wcxb_spi_transfer t_cmd = {
.tx_buf = command,
.len = sizeof(command),
};
struct wcxb_spi_transfer t_data = {
.tx_buf = data,
.len = len,
};
struct wcxb_spi_message m;
/* We need to write on page size boundaries */
WARN_ON(address & 0xff);
wcxb_spi_message_init(&m);
wcxb_spi_message_add_tail(&t_cmd, &m);
wcxb_spi_message_add_tail(&t_data, &m);
while (len) {
res = wcxb_flash_write_enable(spi);
if (res)
return res;
command[1] = (address >> 16) & 0xff;
command[2] = (address >> 8) & 0xff;
t_data.tx_buf = data;
t_data.len = min(len, FLASH_PAGE_SIZE);
res = wcxb_spi_sync(spi, &m);
WARN_ON(res);
if (res)
return res;
res = wcxb_flash_wait_until_not_busy(spi);
WARN_ON(res);
if (res)
return res;
len -= t_data.len;
address += t_data.len;
data += t_data.len;
}
return 0;
}
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