This patch adds the SPI controller for the BCM2835. Polling and interrupt modes
of transfer are supported. DMA and LoSSI modes are currently unimplemented.
Signed-off-by: Rayhan Faizel <rayhan.faizel@gmail.com>
---
docs/system/arm/raspi.rst | 2 +-
hw/ssi/Kconfig | 4 +
hw/ssi/bcm2835_spi.c | 288 +++++++++++++++++++++++++++++++++++
hw/ssi/meson.build | 1 +
include/hw/ssi/bcm2835_spi.h | 81 ++++++++++
5 files changed, 375 insertions(+), 1 deletion(-)
create mode 100644 hw/ssi/bcm2835_spi.c
create mode 100644 include/hw/ssi/bcm2835_spi.h
diff --git a/docs/system/arm/raspi.rst b/docs/system/arm/raspi.rst
index 922fe375a6..d0a6f08b2b 100644
--- a/docs/system/arm/raspi.rst
+++ b/docs/system/arm/raspi.rst
@@ -33,11 +33,11 @@ Implemented devices
* USB2 host controller (DWC2 and MPHI)
* MailBox controller (MBOX)
* VideoCore firmware (property)
+ * Peripheral SPI controller (SPI)
Missing devices
---------------
- * Peripheral SPI controller (SPI)
* Analog to Digital Converter (ADC)
* Pulse Width Modulation (PWM)
diff --git a/hw/ssi/Kconfig b/hw/ssi/Kconfig
index 7d90a02181..83ee53c1d0 100644
--- a/hw/ssi/Kconfig
+++ b/hw/ssi/Kconfig
@@ -20,3 +20,7 @@ config XILINX_SPIPS
config STM32F2XX_SPI
bool
select SSI
+
+config BCM2835_SPI
+ bool
+ select SSI
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)
diff --git a/hw/ssi/meson.build b/hw/ssi/meson.build
index 0aebcdd614..b999aeb027 100644
--- a/hw/ssi/meson.build
+++ b/hw/ssi/meson.build
@@ -11,3 +11,4 @@ system_ss.add(when: 'CONFIG_XLNX_VERSAL', if_true: files('xlnx-versal-ospi.c'))
system_ss.add(when: 'CONFIG_IMX', if_true: files('imx_spi.c'))
system_ss.add(when: 'CONFIG_OMAP', if_true: files('omap_spi.c'))
system_ss.add(when: 'CONFIG_IBEX', if_true: files('ibex_spi_host.c'))
+system_ss.add(when: 'CONFIG_BCM2835_SPI', if_true: files('bcm2835_spi.c'))
diff --git a/include/hw/ssi/bcm2835_spi.h b/include/hw/ssi/bcm2835_spi.h
new file mode 100644
index 0000000000..d3f8cec111
--- /dev/null
+++ b/include/hw/ssi/bcm2835_spi.h
@@ -0,0 +1,81 @@
+/*
+ * 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 "hw/sysbus.h"
+#include "hw/ssi/ssi.h"
+#include "qom/object.h"
+#include "qemu/fifo8.h"
+
+#define TYPE_BCM2835_SPI "bcm2835-spi"
+OBJECT_DECLARE_SIMPLE_TYPE(BCM2835SPIState, BCM2835_SPI)
+
+/*
+ * Though BCM2835 documentation says FIFOs have a capacity of 16,
+ * FIFOs are actually 16 words in size or effectively 64 bytes when operating
+ * in non DMA mode.
+ */
+#define FIFO_SIZE 64
+#define FIFO_SIZE_3_4 48
+
+#define RO_MASK 0x1f0000
+
+#define BCM2835_SPI_CS 0x00
+#define BCM2835_SPI_FIFO 0x04
+#define BCM2835_SPI_CLK 0x08
+#define BCM2835_SPI_DLEN 0x0c
+#define BCM2835_SPI_LTOH 0x10
+#define BCM2835_SPI_DC 0x14
+
+#define BCM2835_SPI_CS_RXF BIT(20)
+#define BCM2835_SPI_CS_RXR BIT(19)
+#define BCM2835_SPI_CS_TXD BIT(18)
+#define BCM2835_SPI_CS_RXD BIT(17)
+#define BCM2835_SPI_CS_DONE BIT(16)
+#define BCM2835_SPI_CS_LEN BIT(13)
+#define BCM2835_SPI_CS_REN BIT(12)
+#define BCM2835_SPI_CS_INTR BIT(10)
+#define BCM2835_SPI_CS_INTD BIT(9)
+#define BCM2835_SPI_CS_DMAEN BIT(8)
+#define BCM2835_SPI_CS_TA BIT(7)
+#define BCM2835_SPI_CLEAR_RX BIT(5)
+#define BCM2835_SPI_CLEAR_TX BIT(4)
+
+struct BCM2835SPIState {
+ /* <private> */
+ SysBusDevice parent_obj;
+
+ /* <public> */
+ SSIBus *bus;
+ MemoryRegion iomem;
+ qemu_irq irq;
+
+ uint32_t cs;
+ uint32_t clk;
+ uint32_t dlen;
+ uint32_t ltoh;
+ uint32_t dc;
+
+ Fifo8 tx_fifo;
+ Fifo8 rx_fifo;
+};
--
2.34.1© 2016 - 2024 Red Hat, Inc.