diff options
Diffstat (limited to 'firmware/usrp3/lib/wb_spi.c')
| -rw-r--r-- | firmware/usrp3/lib/wb_spi.c | 206 |
1 files changed, 206 insertions, 0 deletions
diff --git a/firmware/usrp3/lib/wb_spi.c b/firmware/usrp3/lib/wb_spi.c new file mode 100644 index 000000000..04904feea --- /dev/null +++ b/firmware/usrp3/lib/wb_spi.c @@ -0,0 +1,206 @@ +/* + * Copyright 2014 Free Software Foundation, Inc. + * + * 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, either version 3 of the License, or + * (at your option) any later version. + * + * 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, see <http://www.gnu.org/licenses/>. + */ + +#include <wb_spi.h> +#include <trace.h> + +typedef struct { + volatile uint32_t data0; + volatile uint32_t data1; + volatile uint32_t data2; + volatile uint32_t data3; + volatile uint32_t ctrl_status; + volatile uint32_t clkdiv; + volatile uint32_t slavesel; +} wb_spi_regs_t; + +#define WB_SPI_REGS(base) ((wb_spi_regs_t *) base) + +// Masks for different parts of CTRL reg +#define WB_SPI_CTRL_AUTO_SS (1 << 13) +#define WB_SPI_CTRL_IE (1 << 12) +#define WB_SPI_CTRL_LSB (1 << 11) +#define WB_SPI_CTRL_TXNEG (1 << 10) +#define WB_SPI_CTRL_RXNEG (1 << 9) +#define WB_SPI_CTRL_GO_BSY (1 << 8) +#define WB_SPI_CTRL_LENGTH(x) (x & 0x7F) + +static inline uint32_t _wb_spi_get_flags(const wb_spi_slave_t* slave) +{ + uint32_t flags = 0; + //If the SPI slave samples on the rising edge then shift + //data out on the falling edge. + if (slave->mosi_edge == RISING) flags |= WB_SPI_CTRL_TXNEG; + //If the SPI slave drives on the rising edge then shift + //data in on the falling edge. + if (slave->miso_edge == RISING) flags |= WB_SPI_CTRL_RXNEG; + if (slave->lsb_first) flags |= WB_SPI_CTRL_LSB; + return flags; +} + +static inline void _wait_for_xfer(const wb_spi_slave_t* slave) +{ + while (WB_SPI_REGS(slave->base)->ctrl_status & WB_SPI_CTRL_GO_BSY) { + /*NOP*/ + } +} + +void wb_spi_init(const wb_spi_slave_t* slave) +{ + WB_SPI_REGS(slave->base)->clkdiv = slave->clk_div; + WB_SPI_REGS(slave->base)->slavesel = 0; + + //Do a dummy transaction with no slave selected to prime the engine + uint32_t ctrl = WB_SPI_CTRL_LENGTH(8) | _wb_spi_get_flags(slave); + WB_SPI_REGS(slave->base)->ctrl_status = ctrl | WB_SPI_CTRL_GO_BSY; + _wait_for_xfer(slave); +} + +void _wb_spi_transact_buf( + const wb_spi_slave_t* slave, wb_spi_rw_mode_t rw_mode, + const void* mosi_buf, void* miso_buf, uint32_t length, + bool auto_slave_sel) +{ + if (length == 0) return; + + //Wait for previous transaction to finish + _wait_for_xfer(slave); + + //Write SPI data register(s) + if (mosi_buf) { + uint8_t* mosi_bytes = (uint8_t*) mosi_buf; + uint8_t bits_left = length; + for (uint32_t reg_index = 0; reg_index < 4; reg_index++) { + uint32_t word = 0; + if (bits_left < 32) { + if (bits_left <= 8) { + word = (uint32_t) mosi_bytes[0]; + } else if (bits_left <= 16) { + word = (((uint32_t) mosi_bytes[1]) << 0) | + (((uint32_t) mosi_bytes[0]) << 8); + } else if (bits_left <= 24) { + word = (((uint32_t) mosi_bytes[2]) << 0) | + (((uint32_t) mosi_bytes[1]) << 8) | + (((uint32_t) mosi_bytes[0]) << 16); + } else { + word = *((uint32_t*) mosi_bytes); + } + bits_left = 0; + } else { + word = *((uint32_t*) mosi_bytes); + mosi_bytes += 4; + bits_left -= 32; + } + + switch (reg_index) { + case 0: WB_SPI_REGS(slave->base)->data0 = word; break; + case 1: WB_SPI_REGS(slave->base)->data1 = word; break; + case 2: WB_SPI_REGS(slave->base)->data2 = word; break; + case 3: WB_SPI_REGS(slave->base)->data3 = word; break; + } + + if (bits_left == 0) break; + } + } + + //Compute flags for slave and write control register + uint32_t ctrl = WB_SPI_CTRL_LENGTH(length) | _wb_spi_get_flags(slave); + if (auto_slave_sel) ctrl |= WB_SPI_CTRL_AUTO_SS; + WB_SPI_REGS(slave->base)->ctrl_status = ctrl; + + // Tell it which SPI slave device to access + WB_SPI_REGS(slave->base)->slavesel = slave->slave_sel; + + //Go go go! + WB_SPI_REGS(slave->base)->ctrl_status = ctrl | WB_SPI_CTRL_GO_BSY; + + if (rw_mode == WRITE_READ) { + //Wait for SPI read operation to complete + _wait_for_xfer(slave); + + if (miso_buf) { + //Read SPI data registers + uint8_t* miso_bytes = (uint8_t*) miso_buf; + uint8_t bits_left = length; + for (uint32_t reg_index = 0; reg_index < 4; reg_index++) { + uint32_t word = 0; + switch (reg_index) { + case 0: word = WB_SPI_REGS(slave->base)->data0; break; + case 1: word = WB_SPI_REGS(slave->base)->data1; break; + case 2: word = WB_SPI_REGS(slave->base)->data2; break; + case 3: word = WB_SPI_REGS(slave->base)->data3; break; + } + + if (bits_left < 32) { + if (bits_left <= 8) { + miso_bytes[0] = word & 0xFF; + } else if (bits_left <= 16) { + miso_bytes[1] = word & 0xFF; + miso_bytes[0] = (word >> 8) & 0xFF; + } else if (bits_left <= 24) { + miso_bytes[2] = word & 0xFF; + miso_bytes[1] = (word >> 8) & 0xFF; + miso_bytes[0] = (word >> 16) & 0xFF; + } else { + *((uint32_t*) miso_bytes) = word; + } + bits_left = 0; + } else { + *((uint32_t*) miso_bytes) = word; + miso_bytes += 4; + bits_left -= 32; + } + + if (bits_left == 0) break; + } + } + } +} + +void wb_spi_transact( + const wb_spi_slave_t* slave, wb_spi_rw_mode_t rw_mode, + const void* mosi_buf, void* miso_buf, uint32_t length) +{ + return _wb_spi_transact_buf(slave, rw_mode, mosi_buf, miso_buf, length, true); +} + +void wb_spi_transact_man_ss( + const wb_spi_slave_t* slave, wb_spi_rw_mode_t rw_mode, + const void* mosi_buf, void* miso_buf, uint32_t length) +{ + return _wb_spi_transact_buf(slave, rw_mode, mosi_buf, miso_buf, length, false); +} + +void wb_spi_slave_select(const wb_spi_slave_t* slave) +{ + //Wait for previous transactions to finish + _wait_for_xfer(slave); + //Disable auto slave select + WB_SPI_REGS(slave->base)->ctrl_status = _wb_spi_get_flags(slave); + //Manually select slave + WB_SPI_REGS(slave->base)->slavesel = slave->slave_sel; +} + +void wb_spi_slave_deselect(const wb_spi_slave_t* slave) +{ + //Wait for previous transactions to finish + _wait_for_xfer(slave); + //Disable auto slave select + WB_SPI_REGS(slave->base)->ctrl_status = _wb_spi_get_flags(slave); + //Manually deselect slave + WB_SPI_REGS(slave->base)->slavesel = 0; +} |