diff options
Diffstat (limited to 'firmware/zpu/lib/spi.c')
-rw-r--r-- | firmware/zpu/lib/spi.c | 102 |
1 files changed, 25 insertions, 77 deletions
diff --git a/firmware/zpu/lib/spi.c b/firmware/zpu/lib/spi.c index af0d8a68f..de3645fe3 100644 --- a/firmware/zpu/lib/spi.c +++ b/firmware/zpu/lib/spi.c @@ -1,4 +1,5 @@ /* + * Copyright 2012 Ettus Research LLC * Copyright 2007,2008 Free Software Foundation, Inc. * * This program is free software: you can redistribute it and/or modify @@ -17,94 +18,41 @@ #include "spi.h" #include "memory_map.h" -#include "pic.h" #include "nonstdio.h" +#include "mdelay.h" -//void (*volatile spi_callback)(void); //SPI callback when xfer complete. - -//static void spi_irq_handler(unsigned irq); - -void -spi_init(void) +void spi_init(void) { - /* - * f_sclk = f_wb / ((div + 1) * 2) - */ - spi_regs->div = 1; // 0 = Div by 2 (25 MHz); 1 = Div-by-4 (12.5 MHz) + spi_core->divider = 100; } -void -spi_wait(void) +void spi_wait(void) { - while (spi_regs->ctrl & SPI_CTRL_GO_BSY) - ; + //assumption that divider is reasonably small + mdelay(1); } -uint32_t -spi_transact(bool readback, int slave, uint32_t data, int length, uint32_t flags) +uint32_t spi_transact(bool readback, int slave, uint32_t data, int length, uint32_t flags) { - flags &= (SPI_CTRL_TXNEG | SPI_CTRL_RXNEG); - int ctrl = SPI_CTRL_ASS | (SPI_CTRL_CHAR_LEN_MASK & length) | flags; - - spi_wait(); - - // Tell it which SPI slave device to access - spi_regs->ss = slave & 0xffff; - - // Data we will send - spi_regs->txrx0 = data; + uint32_t control_word = 0; + control_word |= (slave << SPI_CORE_SLAVE_SELECT_SHIFT); + control_word |= (length << SPI_CORE_NUM_BITS_SHIFT); + if ((flags & SPI_PUSH_RISE) != 0) control_word |= (1 << SPI_CORE_DATA_IN_EDGE_SHIFT); + if ((flags & SPI_PUSH_FALL) != 0) control_word |= (0 << SPI_CORE_DATA_IN_EDGE_SHIFT); + if ((flags & SPI_LATCH_RISE) != 0) control_word |= (1 << SPI_CORE_DATA_OUT_EDGE_SHIFT); + if ((flags & SPI_LATCH_FALL) != 0) control_word |= (0 << SPI_CORE_DATA_OUT_EDGE_SHIFT); + + uint32_t data_out_rev = 0; + for (size_t i = 0; i < length; i++){ + const int bit = ((data >> i) & 0x1); + data_out_rev |= (bit << (length - i - 1)); + } - // Run it -- write once and rewrite with GO set - spi_regs->ctrl = ctrl; - spi_regs->ctrl = ctrl | SPI_CTRL_GO_BSY; - - if(readback) { spi_wait(); - return spi_regs->txrx0; - } - else - return 0; -} - -/* -void spi_register_callback(void (*volatile callback)(void)) { - spi_callback = callback; -} - -static void spi_irq_handler(unsigned irq) { -// printf("SPI IRQ handler\n"); -// uint32_t wat = spi_regs->ctrl; //read a register just to clear the interrupt - //spi_regs->ctrl &= ~SPI_CTRL_IE; - if(spi_callback) spi_callback(); //we could just use the PIC to register the user's callback, but this provides the ability to do other things later -} - -uint32_t spi_get_data(void) { - return spi_regs->txrx0; -} - -bool -spi_async_transact(int slave, uint32_t data, int length, uint32_t flags, void (*volatile callback)(void)) { - flags &= (SPI_CTRL_TXNEG | SPI_CTRL_RXNEG); - int ctrl = SPI_CTRL_ASS | SPI_CTRL_IE | (SPI_CTRL_CHAR_LEN_MASK & length) | flags; - - if(spi_regs->ctrl & SPI_CTRL_GO_BSY) { - printf("Async SPI busy!\n"); - return false; //we don't wait on busy, we just return failure. we count on the host to not set up another transaction before the last one finishes. - } - - // Tell it which SPI slave device to access - spi_regs->ss = slave & 0xffff; - - // Data we will send - spi_regs->txrx0 = data; - - spi_register_callback(callback); - pic_register_handler(IRQ_SPI, spi_irq_handler); + spi_core->control = control_word; + spi_core->data = data_out_rev; - // Run it -- write once and rewrite with GO set - spi_regs->ctrl = ctrl; - spi_regs->ctrl = ctrl | SPI_CTRL_GO_BSY; + if (readback) spi_wait(); - return true; + return readback_mux->spi; } -*/ |