litex/software/libbase/spiflash.c

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2014-11-27 10:10:24 -05:00
#include <generated/csr.h>
#include <spiflash.h>
#ifdef SPIFLASH_BASE
#define PAGE_PROGRAM_CMD (0x02)
#define WRDI_CMD (0x04)
#define RDSR_CMD (0x05)
#define WREN_CMD (0x06)
#define SE_CMD (0x20)
#define BITBANG_CLK (1 << 1)
#define BITBANG_CS_N (1 << 2)
#define BITBANG_DQ_INPUT (1 << 3)
#define SR_WIP (1)
#define PAGE_SIZE (256)
#define PAGE_MASK (PAGE_SIZE - 1)
#define SECTOR_SIZE (4096)
#define SECTOR_MASK (SECTOR_SIZE - 1)
static void flash_write_byte(unsigned char b);
static void flash_write_addr(unsigned int addr);
static void wait_for_device_ready(void);
#define min(a,b) (a>b?b:a)
static void flash_write_byte(unsigned char b)
{
int i;
spiflash_bitbang_write(0); // ~CS_N ~CLK
for(i = 0; i < 8; i++, b <<= 1) {
spiflash_bitbang_write((b & 0x80) >> 7);
spiflash_bitbang_write(((b & 0x80) >> 7) | BITBANG_CLK);
}
spiflash_bitbang_write(0); // ~CS_N ~CLK
}
static void flash_write_addr(unsigned int addr)
{
int i;
spiflash_bitbang_write(0);
for(i = 0; i < 24; i++, addr <<= 1) {
spiflash_bitbang_write((addr & 0x800000) >> 23);
spiflash_bitbang_write(((addr & 0x800000) >> 23) | BITBANG_CLK);
}
spiflash_bitbang_write(0);
}
static void wait_for_device_ready(void)
{
unsigned char sr;
unsigned char i;
do {
sr = 0;
flash_write_byte(RDSR_CMD);
spiflash_bitbang_write(BITBANG_DQ_INPUT);
for(i = 0; i < 8; i++) {
sr <<= 1;
spiflash_bitbang_write(BITBANG_CLK | BITBANG_DQ_INPUT);
sr |= spiflash_miso_read();
spiflash_bitbang_write(0 | BITBANG_DQ_INPUT);
}
spiflash_bitbang_write(0);
spiflash_bitbang_write(BITBANG_CS_N);
} while(sr & SR_WIP);
}
void erase_flash_sector(unsigned int addr)
{
unsigned int sector_addr = addr & ~(SECTOR_MASK);
spiflash_bitbang_en_write(1);
wait_for_device_ready();
flash_write_byte(WREN_CMD);
spiflash_bitbang_write(BITBANG_CS_N);
flash_write_byte(SE_CMD);
flash_write_addr(sector_addr);
spiflash_bitbang_write(BITBANG_CS_N);
wait_for_device_ready();
spiflash_bitbang_en_write(0);
}
void write_to_flash_page(unsigned int addr, unsigned char *c, unsigned int len)
{
unsigned int i;
if(len > PAGE_SIZE)
len = PAGE_SIZE;
spiflash_bitbang_en_write(1);
wait_for_device_ready();
flash_write_byte(WREN_CMD);
spiflash_bitbang_write(BITBANG_CS_N);
flash_write_byte(PAGE_PROGRAM_CMD);
flash_write_addr((unsigned int)addr);
for(i = 0; i < len; i++)
flash_write_byte(*c++);
spiflash_bitbang_write(BITBANG_CS_N);
spiflash_bitbang_write(0);
wait_for_device_ready();
spiflash_bitbang_en_write(0);
}
#endif