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/*
* Copyright © 2010 Keith Packard <keithp@keithp.com>
*
* 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; version 2 of the License.
*
* 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.,
* 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA.
*/
#include "ao.h"
/* Total bytes of available storage */
__pdata uint32_t ao_storage_total;
/* Block size - device is erased in these units. At least 256 bytes */
__pdata uint32_t ao_storage_block;
/* Byte offset of config block. Will be ao_storage_block bytes long */
__pdata uint32_t ao_storage_config;
/* Storage unit size - device reads and writes must be within blocks of this size. Usually 256 bytes. */
__pdata uint16_t ao_storage_unit;
/*
* MRAM is entirely random access; no erase operations are required,
* nor are reads or writes restricted to a particular alignment.
*/
#define MR25_WREN 0x06 /* Write Enable */
#define MR25_WRDI 0x04 /* Write Disable */
#define MR25_RDSR 0x05 /* Read Status Register */
#define MR25_WRSR 0x01 /* Write Status Register */
#define MR25_READ 0x03 /* Read Data Bytes */
#define MR25_WRITE 0x02 /* Write Data Bytes */
/*
* Status register bits
*/
#define MR25_STATUS_SRWD (1 << 7) /* Status register write disable */
#define MR25_STATUS_BP_MASK (3 << 2) /* Block protect bits */
#define MR25_STATUS_BP_SHIFT (2)
#define MR25_STATUS_WEL (1 << 1) /* Write enable latch */
static __xdata uint8_t ao_mr25_mutex;
/*
* This little array is abused to send and receive data. A particular
* caution -- the read and write addresses are written into the last
* three bytes of the array by ao_mr25_set_page_address and then the
* first byte is used by ao_mr25_write_enable, neither of which touch
* those last three bytes.
*/
static __xdata uint8_t ao_mr25_instruction[4];
#define MR25_SELECT() ao_spi_get_mask(AO_MR25_SPI_CS_PORT,(1 << AO_MR25_SPI_CS_PIN),AO_MR25_SPI_BUS, AO_SPI_SPEED_FAST)
#define MR25_DESELECT() ao_spi_put_mask(AO_MR25_SPI_CS_PORT,(1 << AO_MR25_SPI_CS_PIN),AO_MR25_SPI_BUS)
/*
* Set the write enable latch so that page program and sector
* erase commands will work. Also mark the chip as busy writing
* so that future operations will block until the WIP bit goes off
*/
static void
ao_mr25_write_enable(void)
{
MR25_SELECT();
ao_mr25_instruction[0] = MR25_WREN;
ao_spi_send(&ao_mr25_instruction, 1, AO_MR25_SPI_BUS);
MR25_DESELECT();
}
static void
ao_mr25_set_address(uint32_t pos)
{
ao_mr25_instruction[1] = pos >> 16;
ao_mr25_instruction[2] = pos >> 8;
ao_mr25_instruction[3] = pos;
}
/*
* Erase the specified sector (no-op for MRAM)
*/
uint8_t
ao_storage_erase(uint32_t pos) __reentrant
{
if (pos >= ao_storage_total || pos + ao_storage_block > ao_storage_total)
return 0;
return 1;
}
/*
* Write to flash
*/
uint8_t
ao_storage_device_write(uint32_t pos, __xdata void *d, uint16_t len) __reentrant
{
if (pos >= ao_storage_total || pos + len > ao_storage_total)
return 0;
ao_mutex_get(&ao_mr25_mutex);
ao_mr25_set_address(pos);
ao_mr25_write_enable();
ao_mr25_instruction[0] = MR25_WRITE;
MR25_SELECT();
ao_spi_send(ao_mr25_instruction, 4, AO_MR25_SPI_BUS);
ao_spi_send(d, len, AO_MR25_SPI_BUS);
MR25_DESELECT();
ao_mutex_put(&ao_mr25_mutex);
return 1;
}
/*
* Read from flash
*/
uint8_t
ao_storage_device_read(uint32_t pos, __xdata void *d, uint16_t len) __reentrant
{
if (pos >= ao_storage_total || pos + len > ao_storage_total)
return 0;
ao_mutex_get(&ao_mr25_mutex);
ao_mr25_set_address(pos);
ao_mr25_instruction[0] = MR25_READ;
MR25_SELECT();
ao_spi_send(ao_mr25_instruction, 4, AO_MR25_SPI_BUS);
ao_spi_recv(d, len, AO_MR25_SPI_BUS);
MR25_DESELECT();
ao_mutex_put(&ao_mr25_mutex);
return 1;
}
void
ao_storage_flush(void) __reentrant
{
}
void
ao_storage_setup(void)
{
}
void
ao_storage_device_info(void) __reentrant
{
printf ("Detected chips 1 size %d\n", ao_storage_total >> 8);
}
void
ao_storage_device_init(void)
{
ao_storage_total = 512 * 1024; /* 4Mb */
ao_storage_block = 256;
ao_storage_config = ao_storage_total - ao_storage_block;
ao_storage_unit = 256;
ao_spi_init_cs (AO_MR25_SPI_CS_PORT, (1 << AO_MR25_SPI_CS_PIN));
}
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