diff options
Diffstat (limited to 'hw/ssi/bcm2835_spi.c')
| -rw-r--r-- | hw/ssi/bcm2835_spi.c | 288 |
1 files changed, 288 insertions, 0 deletions
diff --git a/hw/ssi/bcm2835_spi.c b/hw/ssi/bcm2835_spi.c new file mode 100644 index 0000000000..6ecb42d4e3 --- /dev/null +++ b/hw/ssi/bcm2835_spi.c @@ -0,0 +1,288 @@ +/* + * BCM2835 SPI Master Controller + * + * Copyright (c) 2024 Rayhan Faizel <rayhan.faizel@gmail.com> + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "qemu/log.h" +#include "qemu/fifo8.h" +#include "hw/ssi/bcm2835_spi.h" +#include "hw/irq.h" +#include "migration/vmstate.h" + +static void bcm2835_spi_update_int(BCM2835SPIState *s) +{ + int do_interrupt = 0; + + /* Interrupt on DONE */ + if (s->cs & BCM2835_SPI_CS_INTD && s->cs & BCM2835_SPI_CS_DONE) { + do_interrupt = 1; + } + /* Interrupt on RXR */ + if (s->cs & BCM2835_SPI_CS_INTR && s->cs & BCM2835_SPI_CS_RXR) { + do_interrupt = 1; + } + qemu_set_irq(s->irq, do_interrupt); +} + +static void bcm2835_spi_update_rx_flags(BCM2835SPIState *s) +{ + /* Set RXD if RX FIFO is non empty */ + if (!fifo8_is_empty(&s->rx_fifo)) { + s->cs |= BCM2835_SPI_CS_RXD; + } else { + s->cs &= ~BCM2835_SPI_CS_RXD; + } + + /* Set RXF if RX FIFO is full */ + if (fifo8_is_full(&s->rx_fifo)) { + s->cs |= BCM2835_SPI_CS_RXF; + } else { + s->cs &= ~BCM2835_SPI_CS_RXF; + } + + /* Set RXR if RX FIFO is 3/4th used or above */ + if (fifo8_num_used(&s->rx_fifo) >= FIFO_SIZE_3_4) { + s->cs |= BCM2835_SPI_CS_RXR; + } else { + s->cs &= ~BCM2835_SPI_CS_RXR; + } +} + +static void bcm2835_spi_update_tx_flags(BCM2835SPIState *s) +{ + /* Set TXD if TX FIFO is not full */ + if (fifo8_is_full(&s->tx_fifo)) { + s->cs &= ~BCM2835_SPI_CS_TXD; + } else { + s->cs |= BCM2835_SPI_CS_TXD; + } + + /* Set DONE if in TA mode and TX FIFO is empty */ + if (fifo8_is_empty(&s->tx_fifo) && s->cs & BCM2835_SPI_CS_TA) { + s->cs |= BCM2835_SPI_CS_DONE; + } else { + s->cs &= ~BCM2835_SPI_CS_DONE; + } +} + +static void bcm2835_spi_flush_tx_fifo(BCM2835SPIState *s) +{ + uint8_t tx_byte, rx_byte; + + while (!fifo8_is_empty(&s->tx_fifo) && !fifo8_is_full(&s->rx_fifo)) { + tx_byte = fifo8_pop(&s->tx_fifo); + rx_byte = ssi_transfer(s->bus, tx_byte); + fifo8_push(&s->rx_fifo, rx_byte); + } + + bcm2835_spi_update_tx_flags(s); + bcm2835_spi_update_rx_flags(s); +} + +static uint64_t bcm2835_spi_read(void *opaque, hwaddr addr, unsigned size) +{ + BCM2835SPIState *s = opaque; + uint32_t readval = 0; + + switch (addr) { + case BCM2835_SPI_CS: + readval = s->cs & 0xffffffff; + break; + case BCM2835_SPI_FIFO: + bcm2835_spi_flush_tx_fifo(s); + if (s->cs & BCM2835_SPI_CS_RXD) { + readval = fifo8_pop(&s->rx_fifo); + bcm2835_spi_update_rx_flags(s); + } + + bcm2835_spi_update_int(s); + break; + case BCM2835_SPI_CLK: + readval = s->clk & 0xffff; + break; + case BCM2835_SPI_DLEN: + readval = s->dlen & 0xffff; + break; + case BCM2835_SPI_LTOH: + readval = s->ltoh & 0xf; + break; + case BCM2835_SPI_DC: + readval = s->dc & 0xffffffff; + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__, addr); + } + return readval; +} + +static void bcm2835_spi_write(void *opaque, hwaddr addr, + uint64_t value, unsigned int size) +{ + BCM2835SPIState *s = opaque; + + switch (addr) { + case BCM2835_SPI_CS: + s->cs = (value & ~RO_MASK) | (s->cs & RO_MASK); + if (!(s->cs & BCM2835_SPI_CS_TA)) { + /* Clear DONE and RXR if TA is off */ + s->cs &= ~(BCM2835_SPI_CS_DONE); + s->cs &= ~(BCM2835_SPI_CS_RXR); + } + + /* Clear RX FIFO */ + if (s->cs & BCM2835_SPI_CLEAR_RX) { + fifo8_reset(&s->rx_fifo); + bcm2835_spi_update_rx_flags(s); + } + + /* Clear TX FIFO*/ + if (s->cs & BCM2835_SPI_CLEAR_TX) { + fifo8_reset(&s->tx_fifo); + bcm2835_spi_update_tx_flags(s); + } + + /* Set Transfer Active */ + if (s->cs & BCM2835_SPI_CS_TA) { + bcm2835_spi_update_tx_flags(s); + } + + if (s->cs & BCM2835_SPI_CS_DMAEN) { + qemu_log_mask(LOG_UNIMP, "%s: " \ + "DMA not supported\n", __func__); + } + + if (s->cs & BCM2835_SPI_CS_LEN) { + qemu_log_mask(LOG_UNIMP, "%s: " \ + "LoSSI not supported\n", __func__); + } + + bcm2835_spi_update_int(s); + break; + case BCM2835_SPI_FIFO: + /* + * According to documentation, writes to FIFO without TA controls + * CS and DLEN registers. This is supposed to be used in DMA mode + * which is currently unimplemented. Moreover, Linux does not make + * use of this and directly modifies the CS and DLEN registers. + */ + if (s->cs & BCM2835_SPI_CS_TA) { + if (s->cs & BCM2835_SPI_CS_TXD) { + fifo8_push(&s->tx_fifo, value & 0xff); + bcm2835_spi_update_tx_flags(s); + } + + bcm2835_spi_flush_tx_fifo(s); + bcm2835_spi_update_int(s); + } + break; + case BCM2835_SPI_CLK: + s->clk = value & 0xffff; + break; + case BCM2835_SPI_DLEN: + s->dlen = value & 0xffff; + break; + case BCM2835_SPI_LTOH: + s->ltoh = value & 0xf; + break; + case BCM2835_SPI_DC: + s->dc = value & 0xffffffff; + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Bad offset 0x%" HWADDR_PRIx "\n", __func__, addr); + } +} + +static const MemoryRegionOps bcm2835_spi_ops = { + .read = bcm2835_spi_read, + .write = bcm2835_spi_write, + .endianness = DEVICE_NATIVE_ENDIAN, +}; + +static void bcm2835_spi_realize(DeviceState *dev, Error **errp) +{ + BCM2835SPIState *s = BCM2835_SPI(dev); + s->bus = ssi_create_bus(dev, "spi"); + + memory_region_init_io(&s->iomem, OBJECT(dev), &bcm2835_spi_ops, s, + TYPE_BCM2835_SPI, 0x18); + sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem); + sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq); + + fifo8_create(&s->tx_fifo, FIFO_SIZE); + fifo8_create(&s->rx_fifo, FIFO_SIZE); +} +static void bcm2835_spi_reset(DeviceState *dev) +{ + BCM2835SPIState *s = BCM2835_SPI(dev); + + fifo8_reset(&s->tx_fifo); + fifo8_reset(&s->rx_fifo); + + /* Reset values according to BCM2835 Peripheral Documentation */ + s->cs = BCM2835_SPI_CS_TXD | BCM2835_SPI_CS_REN; + s->clk = 0; + s->dlen = 0; + s->ltoh = 0x1; + s->dc = 0x30201020; +} + +static const VMStateDescription vmstate_bcm2835_spi = { + .name = TYPE_BCM2835_SPI, + .version_id = 1, + .minimum_version_id = 1, + .fields = (const VMStateField[]) { + VMSTATE_FIFO8(tx_fifo, BCM2835SPIState), + VMSTATE_FIFO8(rx_fifo, BCM2835SPIState), + VMSTATE_UINT32(cs, BCM2835SPIState), + VMSTATE_UINT32(clk, BCM2835SPIState), + VMSTATE_UINT32(dlen, BCM2835SPIState), + VMSTATE_UINT32(ltoh, BCM2835SPIState), + VMSTATE_UINT32(dc, BCM2835SPIState), + VMSTATE_END_OF_LIST() + } +}; + +static void bcm2835_spi_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->reset = bcm2835_spi_reset; + dc->realize = bcm2835_spi_realize; + dc->vmsd = &vmstate_bcm2835_spi; +} + +static const TypeInfo bcm2835_spi_info = { + .name = TYPE_BCM2835_SPI, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(BCM2835SPIState), + .class_init = bcm2835_spi_class_init, +}; + +static void bcm2835_spi_register_types(void) +{ + type_register_static(&bcm2835_spi_info); +} + +type_init(bcm2835_spi_register_types) |