mayhem-firmware/firmware/chibios-portapack/boards/PORTAPACK_APPLICATION/fpga_bridge.c

// This bridge allows calls for functions in their native C context
// HackRF headers here - C for use within the C++ board.cpp context

// Check if PRALINE was passed from CMake
#ifdef PRALINE
  #warning "Building for HackRF_PRO with FPGA."

  // Necessary headers
  #include "lz4_blk.h"

  // LIBOPENCM3 Headers (only CGU for clock setup)
  #include <libopencm3/lpc43xx/cgu.h>

  #include <stdint.h>
  #include <stddef.h>
  #include <stdbool.h>
  #include <string.h>

  // SPIFI memory-mapped base address
  // Flash is mapped starting at 0x14000000
  // FPGA bitstream at flash address 0x380000 = memory address 0x14380000
  // PRALINE: Moved to 1.5MB offset to allow larger base firmware
  #define SPIFI_DATA_BASE 0x14000000
  #define FPGA_BITSTREAM_FLASH_ADDR 0x380000  // Was 0x100000 (1MB), then 0x180000 (1.5MB), now 0x380000 (3.5MB)
  #define FPGA_BITSTREAM_MEM_ADDR (SPIFI_DATA_BASE + FPGA_BITSTREAM_FLASH_ADDR)

  // MMIO32 direct register access
  #define MMIO32_LOCAL(addr) (*(volatile uint32_t*)(addr))

  // SSP1 base address
  #define SSP1_BASE_LOCAL 0x400C5000

  // SSP register offsets
  #define SSP_CR0_OFF   0x000
  #define SSP_CR1_OFF   0x004
  #define SSP_DR_OFF    0x008
  #define SSP_SR_OFF    0x00C
  #define SSP_CPSR_OFF  0x010

  // SSP register access
  #define SSP1_CR0_LOCAL  MMIO32_LOCAL(SSP1_BASE_LOCAL + SSP_CR0_OFF)
  #define SSP1_CR1_LOCAL  MMIO32_LOCAL(SSP1_BASE_LOCAL + SSP_CR1_OFF)
  #define SSP1_DR_LOCAL   MMIO32_LOCAL(SSP1_BASE_LOCAL + SSP_DR_OFF)
  #define SSP1_SR_LOCAL   MMIO32_LOCAL(SSP1_BASE_LOCAL + SSP_SR_OFF)
  #define SSP1_CPSR_LOCAL MMIO32_LOCAL(SSP1_BASE_LOCAL + SSP_CPSR_OFF)

  // SSP status bits
  #define SSP_SR_TNF_LOCAL (1 << 1)  // TX FIFO not full
  #define SSP_SR_RNE_LOCAL (1 << 2)  // RX FIFO not empty
  #define SSP_SR_BSY_LOCAL (1 << 4)  // Busy

  // SSP CR0 bits
  #define SSP_CR0_DSS_8BIT (0x7)     // 8-bit data
  #define SSP_CR0_FRF_SPI  (0x0)     // SPI frame format
  #define SSP_CR0_CPOL     (1 << 6)  // Clock polarity
  #define SSP_CR0_CPHA     (1 << 7)  // Clock phase

  // SSP CR1 bits
  #define SSP_CR1_SSE      (1 << 1)  // SSP enable

  // SCU pin configuration registers
  #define PERIPH_BASE_APB0_LOCAL 0x40080000
  #define SCU_BASE_LOCAL (PERIPH_BASE_APB0_LOCAL + 0x06000)
  #define PIN_GROUP1_LOCAL (SCU_BASE_LOCAL + 0x080)
  #define PIN_GROUP4_LOCAL (SCU_BASE_LOCAL + 0x200)
  #define PIN_GROUP5_LOCAL (SCU_BASE_LOCAL + 0x280)
  #define PIN3_LOCAL 0x00C
  #define PIN4_LOCAL 0x010
  #define PIN1_LOCAL 0x004
  #define PIN2_LOCAL 0x008
  #define PIN10_LOCAL 0x028
  #define PIN19_LOCAL 0x04C

  // SCU configuration flags
  #define SCU_CONF_EPUN_DIS_PULLUP_LOCAL (1 << 4)
  #define SCU_CONF_EHS_FAST_LOCAL (1 << 5)
  #define SCU_CONF_EZI_EN_IN_BUFFER_LOCAL (1 << 6)
  #define SCU_CONF_ZIF_DIS_IN_GLITCH_FILT_LOCAL (1 << 7)
  #define SCU_GPIO_FAST_LOCAL (SCU_CONF_EPUN_DIS_PULLUP_LOCAL | \
                               SCU_CONF_EHS_FAST_LOCAL | \
                               SCU_CONF_EZI_EN_IN_BUFFER_LOCAL | \
                               SCU_CONF_ZIF_DIS_IN_GLITCH_FILT_LOCAL)
  #define SCU_SSP_IO_LOCAL SCU_GPIO_FAST_LOCAL

  // Function select values
  #define SCU_CONF_FUNCTION0_LOCAL (0x0)
  #define SCU_CONF_FUNCTION1_LOCAL (0x1)
  #define SCU_CONF_FUNCTION4_LOCAL (0x4)
  #define SCU_CONF_FUNCTION5_LOCAL (0x5)
  #define SCU_GPIO_NOPULL_LOCAL (SCU_CONF_EZI_EN_IN_BUFFER_LOCAL | SCU_CONF_ZIF_DIS_IN_GLITCH_FILT_LOCAL)
  #define SCU_GPIO_PUP_LOCAL (SCU_CONF_EZI_EN_IN_BUFFER_LOCAL)

  // SSP1 pins (for FPGA programming)
  #define SCU_SSP1_CIPO_LOCAL (PIN_GROUP1_LOCAL + PIN3_LOCAL)   // P1_3
  #define SCU_SSP1_COPI_LOCAL (PIN_GROUP1_LOCAL + PIN4_LOCAL)   // P1_4
  #define SCU_SSP1_SCK_LOCAL (PIN_GROUP1_LOCAL + PIN19_LOCAL)   // P1_19

  // FPGA control pins
  #define SCU_FPGA_CRESET_LOCAL (PIN_GROUP5_LOCAL + PIN2_LOCAL)  // P5_2 GPIO2[11]
  #define SCU_FPGA_CDONE_LOCAL (PIN_GROUP4_LOCAL + PIN10_LOCAL)  // P4_10 GPIO5[14]
  #define SCU_FPGA_SPI_CS_LOCAL (PIN_GROUP5_LOCAL + PIN1_LOCAL)  // P5_1 GPIO2[10]

  // GPIO register addresses for direct MMIO access
  #define GPIO_LPC_BASE_LOCAL 0x400F4000
  #define GPIO_DIR_BASE (GPIO_LPC_BASE_LOCAL + 0x2000)  // Direction registers
  #define GPIO_SET_BASE (GPIO_LPC_BASE_LOCAL + 0x2200)  // Set registers
  #define GPIO_CLR_BASE (GPIO_LPC_BASE_LOCAL + 0x2280)  // Clear registers
  #define GPIO_PIN_BASE (GPIO_LPC_BASE_LOCAL + 0x2100)  // Pin read registers

  // GPIO port access macros
  #define GPIO_DIR(port) MMIO32_LOCAL(GPIO_DIR_BASE + (port)*4)
  #define GPIO_SET(port) MMIO32_LOCAL(GPIO_SET_BASE + (port)*4)
  #define GPIO_CLR(port) MMIO32_LOCAL(GPIO_CLR_BASE + (port)*4)
  #define GPIO_PIN(port) MMIO32_LOCAL(GPIO_PIN_BASE + (port)*4)

  // FPGA control GPIO pins
  // GPIO2[11] = CRESET, GPIO5[14] = CDONE, GPIO2[10] = SPI_CS
  #define FPGA_CRESET_PORT 2
  #define FPGA_CRESET_PIN  11
  #define FPGA_CDONE_PORT  5
  #define FPGA_CDONE_PIN   14
  #define FPGA_SPI_CS_PORT 2
  #define FPGA_SPI_CS_PIN  10

  // Context structure for SPIFI-based reading
  struct spifi_fpga_read_ctx {
      const uint8_t* mem_ptr;    // Current read position in SPIFI memory
      size_t next_block_sz;
      uint8_t init_flag;
      uint8_t buffer[4096 + 2];  // Compressed block + next size
  };

  // Simple delay loop
  static void delay_cycles(volatile uint32_t count) {
      while (count--) {
          __asm__ volatile ("nop");
      }
  }

  // Microsecond delay (approximate, assuming ~200MHz clock)
  static void delay_us(uint32_t us) {
      // ~50 cycles per microsecond at 200MHz
      delay_cycles(us * 50);
  }

  // SSP1 transfer one byte
  static uint8_t ssp1_transfer_byte(uint8_t data) {
      // Wait for TX FIFO not full
      while ((SSP1_SR_LOCAL & SSP_SR_TNF_LOCAL) == 0) {}
      SSP1_DR_LOCAL = data;
      // Wait for not busy
      while (SSP1_SR_LOCAL & SSP_SR_BSY_LOCAL) {}
      // Wait for RX FIFO not empty
      while ((SSP1_SR_LOCAL & SSP_SR_RNE_LOCAL) == 0) {}
      return SSP1_DR_LOCAL;
  }

  // Configure SSP1 for iCE40 programming (SPI mode 3: CPOL=1, CPHA=1)
  static void ssp1_init_ice40(void) {
      // Disable SSP1 first
      SSP1_CR1_LOCAL = 0;

      // Configure: 8-bit, SPI mode 3 (CPOL=1, CPHA=1), master mode
      // SCR=21 for ~4MHz at 200MHz clock
      SSP1_CR0_LOCAL = SSP_CR0_DSS_8BIT | SSP_CR0_FRF_SPI | SSP_CR0_CPOL | SSP_CR0_CPHA | (21 << 8);

      // Clock prescaler = 2 (divide by 2)
      SSP1_CPSR_LOCAL = 2;

      // Enable SSP1
      SSP1_CR1_LOCAL = SSP_CR1_SSE;
  }

  // Configure SSP1 pins via SCU
  static void configure_ssp1_pins(void) {
      // P1_3 = SSP1_MISO (function 5)
      MMIO32_LOCAL(SCU_SSP1_CIPO_LOCAL) = SCU_SSP_IO_LOCAL | SCU_CONF_FUNCTION5_LOCAL;
      // P1_4 = SSP1_MOSI (function 5)
      MMIO32_LOCAL(SCU_SSP1_COPI_LOCAL) = SCU_SSP_IO_LOCAL | SCU_CONF_FUNCTION5_LOCAL;
      // P1_19 = SSP1_SCK (function 1)
      MMIO32_LOCAL(SCU_SSP1_SCK_LOCAL) = SCU_SSP_IO_LOCAL | SCU_CONF_FUNCTION1_LOCAL;
  }

  // Configure FPGA control pins via SCU and GPIO
  static void configure_fpga_control_pins(void) {
      // P5_2 = GPIO2[11] = CRESET (function 0, output)
      MMIO32_LOCAL(SCU_FPGA_CRESET_LOCAL) = SCU_GPIO_NOPULL_LOCAL | SCU_CONF_FUNCTION0_LOCAL;
      // P4_10 = GPIO5[14] = CDONE (function 4, input with pullup)
      MMIO32_LOCAL(SCU_FPGA_CDONE_LOCAL) = SCU_GPIO_PUP_LOCAL | SCU_CONF_FUNCTION4_LOCAL;
      // P5_1 = GPIO2[10] = SPI_CS (function 0, output)
      MMIO32_LOCAL(SCU_FPGA_SPI_CS_LOCAL) = SCU_GPIO_NOPULL_LOCAL | SCU_CONF_FUNCTION0_LOCAL;

      // Set CRESET and SPI_CS as outputs (GPIO2[11] and GPIO2[10])
      GPIO_DIR(FPGA_CRESET_PORT) |= (1 << FPGA_CRESET_PIN) | (1 << FPGA_SPI_CS_PIN);
      // Clear both initially
      GPIO_CLR(FPGA_CRESET_PORT) = (1 << FPGA_CRESET_PIN) | (1 << FPGA_SPI_CS_PIN);

      // CDONE is input (GPIO5[14])
      GPIO_DIR(FPGA_CDONE_PORT) &= ~(1 << FPGA_CDONE_PIN);
  }

  // GPIO control helpers
  static void fpga_creset_low(void) {
      GPIO_CLR(FPGA_CRESET_PORT) = (1 << FPGA_CRESET_PIN);
  }
  static void fpga_creset_high(void) {
      GPIO_SET(FPGA_CRESET_PORT) = (1 << FPGA_CRESET_PIN);
  }
  static void fpga_cs_low(void) {
      GPIO_CLR(FPGA_SPI_CS_PORT) = (1 << FPGA_SPI_CS_PIN);
  }
  static void fpga_cs_high(void) {
      GPIO_SET(FPGA_SPI_CS_PORT) = (1 << FPGA_SPI_CS_PIN);
  }
  static bool fpga_cdone_read(void) {
      return (GPIO_PIN(FPGA_CDONE_PORT) & (1 << FPGA_CDONE_PIN)) != 0;
  }

  // ============================================================================
  // FPGA Register Access via SPI (iCE40)
  // ============================================================================
  // These functions allow reading/writing FPGA internal registers via SPI.
  // The FPGA bitstream implements a simple SPI register interface.
  //
  // FPGA Register Map:
  //   Reg 1 (CTRL):    DC_BLOCK(b0), QUARTER_SHIFT_EN(b1), QUARTER_SHIFT_UP(b2), PRBS(b6), TRIGGER_EN(b7)
  //   Reg 2 (RX_DECIM): Decimation ratio [2:0]
  //   Reg 3 (TX_CTRL):  NCO_EN(b0)
  //   Reg 4 (TX_INTRP): Interpolation ratio [2:0]
  //   Reg 5 (TX_PSTEP): NCO phase step [7:0]
  //
  // SPI Protocol:
  //   Read:  Send [reg & 0x7F, 0x00, 0x00] -> value in byte 3
  //   Write: Send [(reg | 0x80), value, 0x00]

  // Configure SSP1 for iCE40 FPGA register access (Mode 3, 8-bit)
  static void ssp1_set_mode_ice40(void) {
      SSP1_CR1_LOCAL = 0;  // Disable SSP1
      SSP1_CR0_LOCAL = SSP_CR0_DSS_8BIT | SSP_CR0_FRF_SPI | SSP_CR0_CPOL | SSP_CR0_CPHA | (21 << 8);
      SSP1_CPSR_LOCAL = 2;
      SSP1_CR1_LOCAL = SSP_CR1_SSE;  // Enable SSP1
  }

  // Configure SSP1 back to MAX2831 mode (Mode 0, 9-bit)
  static void ssp1_set_mode_max2831(void) {
      SSP1_CR1_LOCAL = 0;  // Disable SSP1
      SSP1_CR0_LOCAL = (0x08) |           // 9-bit data (DSS = 0x08)
                       (0x00) |           // SPI frame format
                       (0 << 6) |         // CPOL = 0 (Mode 0)
                       (0 << 7) |         // CPHA = 0 (Mode 0)
                       (21 << 8);         // SCR = 21
      SSP1_CPSR_LOCAL = 2;
      SSP1_CR1_LOCAL = SSP_CR1_SSE;  // Enable SSP1
  }

  // Read an FPGA register via SPI
  static uint8_t fpga_spi_read(uint8_t reg) {
      uint8_t value;
      fpga_cs_low();
      ssp1_transfer_byte(reg & 0x7F);  // Clear MSB for read
      ssp1_transfer_byte(0x00);         // Dummy byte
      value = ssp1_transfer_byte(0x00); // Read value
      fpga_cs_high();
      return value;
  }

  // Write an FPGA register via SPI
  static void fpga_spi_write(uint8_t reg, uint8_t value) {
      fpga_cs_low();
      ssp1_transfer_byte((reg & 0x7F) | 0x80);  // Set MSB for write
      ssp1_transfer_byte(value);
      ssp1_transfer_byte(0x00);  // Dummy byte
      fpga_cs_high();
  }

  // Initialize FPGA registers after bitstream load
  // This is equivalent to fpga_init() in the reference HackRF firmware
  static void fpga_register_init(void) {
      // Already in iCE40 mode after programming, so we can directly access registers

      // Register 1 (CTRL): Enable DC block (bit 0), disable everything else
      // DC_BLOCK is CRITICAL for RX to work!
      fpga_spi_write(1, 0x01);  // DC_BLOCK = 1

      // Register 2 (RX_DECIM): No decimation
      fpga_spi_write(2, 0x00);

      // Register 3 (TX_CTRL): Disable NCO
      fpga_spi_write(3, 0x00);

      // Register 4 (TX_INTRP): No interpolation
      fpga_spi_write(4, 0x00);

      // Register 5 (TX_PSTEP): Zero phase step
      fpga_spi_write(5, 0x00);
  }

  // Cached register values for debug reads (since reads may require mode switch)
  static uint8_t fpga_reg_cache[6] = {0, 0x01, 0x00, 0x00, 0x00, 0x00};
  static uint8_t fpga_reg_cache_valid = 0;

  // Public function to read FPGA register (callable from C++ application code)
  // Switches SPI mode, reads register, switches back
  uint8_t fpga_debug_register_read(uint8_t reg) {
      if (reg == 0 || reg > 5) return 0xFF;

      uint8_t value;
      ssp1_set_mode_ice40();
      value = fpga_spi_read(reg);
      ssp1_set_mode_max2831();

      fpga_reg_cache[reg] = value;
      return value;
  }

  // Public function to write FPGA register (callable from C++ application code)
  void fpga_debug_register_write(uint8_t reg, uint8_t value) {
      if (reg == 0 || reg > 5) return;

      ssp1_set_mode_ice40();
      fpga_spi_write(reg, value);
      ssp1_set_mode_max2831();

      fpga_reg_cache[reg] = value;
  }

  // SPIFI-based read callback for LZ4 decompression
  // Reads from SPIFI memory-mapped address instead of using SPI flash driver
  static size_t spifi_fpga_read_block_cb(void* _ctx, uint8_t* out_buffer) {
      struct spifi_fpga_read_ctx* ctx = (struct spifi_fpga_read_ctx*)_ctx;
      size_t block_sz = ctx->next_block_sz;

      // First iteration: read first block size from SPIFI memory
      if (ctx->init_flag == 0) {
          block_sz = ctx->mem_ptr[0] | (ctx->mem_ptr[1] << 8);
          ctx->mem_ptr += 2;
          ctx->init_flag = 1;
      }

      // Finish at end marker (block_sz == 0)
      if (block_sz == 0) return 0;

      // Read compressed block from SPIFI memory
      memcpy(ctx->buffer, ctx->mem_ptr, block_sz + 2);
      ctx->mem_ptr += block_sz + 2;

      // Extract next block size
      ctx->next_block_sz = ctx->buffer[block_sz] | (ctx->buffer[block_sz + 1] << 8);

      // Decompress block using LZ4
      return lz4_blk_decompress(ctx->buffer, out_buffer, block_sz);
  }

  // Program iCE40 FPGA using SPIFI memory-mapped data
  // Based on ice40_spi_syscfg_program() from ice40_spi.c
  static bool program_fpga_from_spifi(const uint8_t* bitstream_start) {
      // Drive CRESET_B = 0, SPI_SS = 0
      fpga_creset_low();
      fpga_cs_low();

      // Wait minimum 200ns
      delay_us(1);

      // Release CRESET_B (drive high)
      fpga_creset_high();

      // Wait minimum 1200us (we wait 1800us to be safe)
      delay_us(1800);

      // Set SPI_SS = 1, send 8 dummy clocks
      fpga_cs_high();
      ssp1_transfer_byte(0);

      // Send configuration image
      // Use static buffers to avoid stack overflow (~8KB would be needed)
      static uint8_t out_buffer[4096];
      static struct spifi_fpga_read_ctx ctx;
      ctx.mem_ptr = bitstream_start;
      ctx.next_block_sz = 0;
      ctx.init_flag = 0;

      fpga_cs_low();
      // Full LZ4 decompress and send all bytes
      for (;;) {
          size_t read_sz = spifi_fpga_read_block_cb(&ctx, out_buffer);
          if (read_sz == 0) break;
          for (size_t j = 0; j < read_sz; j++) {
              ssp1_transfer_byte(out_buffer[j]);
          }
      }

      // Wait for 100 clock cycles for CDONE to go high
      fpga_cs_high();
      for (size_t j = 0; j < 13; j++) {
          ssp1_transfer_byte(0);
      }

      // Check CDONE status
      bool success = fpga_cdone_read();

      // NOTE: FPGA register initialization is done later in radio::init()
      // The FPGA needs time to stabilize after configuration before accepting register writes

      // CRITICAL: Reconfigure SSP1 for MAX2831 (PRALINE RF chip) after FPGA programming
      // iCE40 uses Mode 3 (CPOL=1, CPHA=1), 8-bit
      // MAX2831 (PRALINE) uses Mode 0 (CPOL=0, CPHA=0), 9-bit (vs 16-bit for MAX283x on HackRF One)
      // Without this, RF communication will fail!
      /*SSP1_CR1_LOCAL = 0;  // Disable SSP1
      SSP1_CR0_LOCAL = (0x08) |           // 9-bit data (DSS = 0x08) for MAX2831/PRALINE
                       (0x00) |           // SPI frame format
                       (0 << 6) |         // CPOL = 0 (Mode 0)
                       (0 << 7) |         // CPHA = 0 (Mode 0)
                       (21 << 8);         // SCR = 21 (same as ssp_config_max283x for PRALINE)
      SSP1_CPSR_LOCAL = 2;                // Clock prescaler
      SSP1_CR1_LOCAL = SSP_CR1_SSE;       // Re-enable SSP1*/

      return success;
  }

  int fpga_bridge_init(void) {
      // Enable SSP1 clock for FPGA programming
      // Use PLL1 (204MHz) to match original HackRF - IRC (12MHz) is 17x too slow
      CGU_BASE_SSP1_CLK = CGU_BASE_SSP1_CLK_AUTOBLOCK(1) |
                         CGU_BASE_SSP1_CLK_CLK_SEL(CGU_SRC_PLL1);

      // Configure SSP1 pins
      configure_ssp1_pins();

      // Configure FPGA control pins
      configure_fpga_control_pins();

      // Initialize SSP1 for iCE40 programming
      ssp1_init_ice40();

      // Read FPGA bitstream header from SPIFI memory
      const uint8_t* fpga_header = (const uint8_t*)FPGA_BITSTREAM_MEM_ADDR;
      uint32_t num_bitstreams = fpga_header[0] | (fpga_header[1] << 8) |
                                (fpga_header[2] << 16) | (fpga_header[3] << 24);

      // Check if header looks valid
      if (num_bitstreams == 0 || num_bitstreams > 16 || num_bitstreams == 0xFFFFFFFF) {
          // No valid FPGA bitstream - skip programming but continue boot
          return 1;
      }

      // Get offset of first bitstream (index 0 = standard_fpga)
      uint32_t bitstream_offset = fpga_header[4] | (fpga_header[5] << 8) |
                                  (fpga_header[6] << 16) | (fpga_header[7] << 24);

      // Calculate start address of first bitstream in SPIFI memory
      const uint8_t* bitstream_start = (const uint8_t*)(FPGA_BITSTREAM_MEM_ADDR + bitstream_offset);

      // Full FPGA programming
      bool success = program_fpga_from_spifi(bitstream_start);

      // Initialize FPGA registers immediately after programming
      if (success) {
          // Give FPGA 100us to stabilize after configuration
          delay_us(100);
      
          // Initialize FPGA registers (DC_BLOCK, etc.)
          fpga_register_init();
      
          // Now switch to MAX2831 mode
          ssp1_set_mode_max2831();
      }

      return success ? 0 : 2;
  }
#else
#warning "Building for HackRF_One with CPLD."
#endif