spiflash_sw

diff --git a/software/main.c b/software/main.c
index 005a883..09208b9 100644
--- a/software/main.c
+++ b/software/main.c
@@ -7,6 +7,130 @@
 #include <console.h>
 #include <generated/csr.h>

+#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 << 2)
+#define BITBANG_CS_N       (1 << 3)
+#define BITBANG_DQ_INPUT   (1 << 4)
+#define BITBANG_ENABLE     (1 << 5)
+
+#define SR_WIP         (1)
+
+static inline void _spiflash_bitbang_write(unsigned int val);
+void flash_write_byte(unsigned char b);
+void flash_write_addr(unsigned int addr);
+void write_to_flash(unsigned int addr, char c);
+void wait_for_device_ready(void);
+
+static inline void _spiflash_bitbang_write(unsigned int val)
+{
+   spiflash_bitbang_write(val | BITBANG_ENABLE);
+}
+
+void flash_write_byte(unsigned char cmd)
+{
+   int i;
+   _spiflash_bitbang_write(0); // ~CS_N ~CLK
+
+   for (i = 0 ; i < 8 ; i++, cmd <<= 1)
+   {
+
+       _spiflash_bitbang_write((cmd & 0x80) >> 7);
+       _spiflash_bitbang_write(((cmd & 0x80) >> 7) | BITBANG_CLK);
+   }
+
+   _spiflash_bitbang_write(0); // ~CS_N ~CLK
+
+}
+
+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);
+}
+
+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);
+       printf("sr == %02x\n", sr);
+   } while (sr & SR_WIP);
+}
+
+void erase_flash(unsigned int addr)
+{
+   unsigned int sector_addr = addr & ~(0xfff);
+   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);
+}
+
+void write_to_flash(unsigned int addr, char c)
+{
+   unsigned int i;
+   flash_write_byte(WREN_CMD);
+   _spiflash_bitbang_write(BITBANG_CS_N);
+   flash_write_byte(PAGE_PROGRAM_CMD);
+   flash_write_addr(addr);
+   for (i = 0 ; i < 256 ; i++)
+       flash_write_byte(c);
+
+   _spiflash_bitbang_write(BITBANG_CS_N);
+   spiflash_bitbang_write(0);
+}
+
+void erase_then_write_to_flash(unsigned int addr, char c)
+{
+   unsigned int sector_addr = addr & ~(0xfff);
+
+   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();
+
+   flash_write_byte(WREN_CMD);
+   _spiflash_bitbang_write(BITBANG_CS_N);
+   flash_write_byte(PAGE_PROGRAM_CMD);
+   flash_write_addr(addr);
+   flash_write_byte(c);
+
+   _spiflash_bitbang_write(BITBANG_CS_N);
+   spiflash_bitbang_write(0);
+}
+
 int main(void)
 {
    int c;
@@ -19,6 +143,12 @@ int main(void)

    while(1) {
        c = readchar();
+       if (c == '0')
+           erase_flash(0x75000);
+       if (c == '1')
+           write_to_flash(0x75000, '@');
+       if (c == '2')
+           erase_then_write_to_flash(0x75000, '%');
        if((c >= '0') && (c <= '9')) {
            printf("Set blink frequency #%c\n", c);
            c -= '0';