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-rw-r--r--hw/ssi/sifive_spi.c358
1 files changed, 358 insertions, 0 deletions
diff --git a/hw/ssi/sifive_spi.c b/hw/ssi/sifive_spi.c
new file mode 100644
index 0000000000..0c9ebca3c8
--- /dev/null
+++ b/hw/ssi/sifive_spi.c
@@ -0,0 +1,358 @@
+/*
+ * QEMU model of the SiFive SPI Controller
+ *
+ * Copyright (c) 2021 Wind River Systems, Inc.
+ *
+ * Author:
+ * Bin Meng <bin.meng@windriver.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2 or later, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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 "qemu/osdep.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "hw/sysbus.h"
+#include "hw/ssi/ssi.h"
+#include "sysemu/sysemu.h"
+#include "qemu/fifo8.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "hw/ssi/sifive_spi.h"
+
+#define R_SCKDIV (0x00 / 4)
+#define R_SCKMODE (0x04 / 4)
+#define R_CSID (0x10 / 4)
+#define R_CSDEF (0x14 / 4)
+#define R_CSMODE (0x18 / 4)
+#define R_DELAY0 (0x28 / 4)
+#define R_DELAY1 (0x2C / 4)
+#define R_FMT (0x40 / 4)
+#define R_TXDATA (0x48 / 4)
+#define R_RXDATA (0x4C / 4)
+#define R_TXMARK (0x50 / 4)
+#define R_RXMARK (0x54 / 4)
+#define R_FCTRL (0x60 / 4)
+#define R_FFMT (0x64 / 4)
+#define R_IE (0x70 / 4)
+#define R_IP (0x74 / 4)
+
+#define FMT_DIR (1 << 3)
+
+#define TXDATA_FULL (1 << 31)
+#define RXDATA_EMPTY (1 << 31)
+
+#define IE_TXWM (1 << 0)
+#define IE_RXWM (1 << 1)
+
+#define IP_TXWM (1 << 0)
+#define IP_RXWM (1 << 1)
+
+#define FIFO_CAPACITY 8
+
+static void sifive_spi_txfifo_reset(SiFiveSPIState *s)
+{
+ fifo8_reset(&s->tx_fifo);
+
+ s->regs[R_TXDATA] &= ~TXDATA_FULL;
+ s->regs[R_IP] &= ~IP_TXWM;
+}
+
+static void sifive_spi_rxfifo_reset(SiFiveSPIState *s)
+{
+ fifo8_reset(&s->rx_fifo);
+
+ s->regs[R_RXDATA] |= RXDATA_EMPTY;
+ s->regs[R_IP] &= ~IP_RXWM;
+}
+
+static void sifive_spi_update_cs(SiFiveSPIState *s)
+{
+ int i;
+
+ for (i = 0; i < s->num_cs; i++) {
+ if (s->regs[R_CSDEF] & (1 << i)) {
+ qemu_set_irq(s->cs_lines[i], !(s->regs[R_CSMODE]));
+ }
+ }
+}
+
+static void sifive_spi_update_irq(SiFiveSPIState *s)
+{
+ int level;
+
+ if (fifo8_num_used(&s->tx_fifo) < s->regs[R_TXMARK]) {
+ s->regs[R_IP] |= IP_TXWM;
+ } else {
+ s->regs[R_IP] &= ~IP_TXWM;
+ }
+
+ if (fifo8_num_used(&s->rx_fifo) > s->regs[R_RXMARK]) {
+ s->regs[R_IP] |= IP_RXWM;
+ } else {
+ s->regs[R_IP] &= ~IP_RXWM;
+ }
+
+ level = s->regs[R_IP] & s->regs[R_IE] ? 1 : 0;
+ qemu_set_irq(s->irq, level);
+}
+
+static void sifive_spi_reset(DeviceState *d)
+{
+ SiFiveSPIState *s = SIFIVE_SPI(d);
+
+ memset(s->regs, 0, sizeof(s->regs));
+
+ /* The reset value is high for all implemented CS pins */
+ s->regs[R_CSDEF] = (1 << s->num_cs) - 1;
+
+ /* Populate register with their default value */
+ s->regs[R_SCKDIV] = 0x03;
+ s->regs[R_DELAY0] = 0x1001;
+ s->regs[R_DELAY1] = 0x01;
+
+ sifive_spi_txfifo_reset(s);
+ sifive_spi_rxfifo_reset(s);
+
+ sifive_spi_update_cs(s);
+ sifive_spi_update_irq(s);
+}
+
+static void sifive_spi_flush_txfifo(SiFiveSPIState *s)
+{
+ uint8_t tx;
+ uint8_t rx;
+
+ while (!fifo8_is_empty(&s->tx_fifo)) {
+ tx = fifo8_pop(&s->tx_fifo);
+ rx = ssi_transfer(s->spi, tx);
+
+ if (!fifo8_is_full(&s->rx_fifo)) {
+ if (!(s->regs[R_FMT] & FMT_DIR)) {
+ fifo8_push(&s->rx_fifo, rx);
+ }
+ }
+ }
+}
+
+static bool sifive_spi_is_bad_reg(hwaddr addr, bool allow_reserved)
+{
+ bool bad;
+
+ switch (addr) {
+ /* reserved offsets */
+ case 0x08:
+ case 0x0C:
+ case 0x1C:
+ case 0x20:
+ case 0x24:
+ case 0x30:
+ case 0x34:
+ case 0x38:
+ case 0x3C:
+ case 0x44:
+ case 0x58:
+ case 0x5C:
+ case 0x68:
+ case 0x6C:
+ bad = allow_reserved ? false : true;
+ break;
+ default:
+ bad = false;
+ }
+
+ if (addr >= (SIFIVE_SPI_REG_NUM << 2)) {
+ bad = true;
+ }
+
+ return bad;
+}
+
+static uint64_t sifive_spi_read(void *opaque, hwaddr addr, unsigned int size)
+{
+ SiFiveSPIState *s = opaque;
+ uint32_t r;
+
+ if (sifive_spi_is_bad_reg(addr, true)) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: bad read at address 0x%"
+ HWADDR_PRIx "\n", __func__, addr);
+ return 0;
+ }
+
+ addr >>= 2;
+ switch (addr) {
+ case R_TXDATA:
+ if (fifo8_is_full(&s->tx_fifo)) {
+ return TXDATA_FULL;
+ }
+ r = 0;
+ break;
+
+ case R_RXDATA:
+ if (fifo8_is_empty(&s->rx_fifo)) {
+ return RXDATA_EMPTY;
+ }
+ r = fifo8_pop(&s->rx_fifo);
+ break;
+
+ default:
+ r = s->regs[addr];
+ break;
+ }
+
+ sifive_spi_update_irq(s);
+
+ return r;
+}
+
+static void sifive_spi_write(void *opaque, hwaddr addr,
+ uint64_t val64, unsigned int size)
+{
+ SiFiveSPIState *s = opaque;
+ uint32_t value = val64;
+
+ if (sifive_spi_is_bad_reg(addr, false)) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: bad write at addr=0x%"
+ HWADDR_PRIx " value=0x%x\n", __func__, addr, value);
+ return;
+ }
+
+ addr >>= 2;
+ switch (addr) {
+ case R_CSID:
+ if (value >= s->num_cs) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid csid %d\n",
+ __func__, value);
+ } else {
+ s->regs[R_CSID] = value;
+ sifive_spi_update_cs(s);
+ }
+ break;
+
+ case R_CSDEF:
+ if (value >= (1 << s->num_cs)) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid csdef %x\n",
+ __func__, value);
+ } else {
+ s->regs[R_CSDEF] = value;
+ }
+ break;
+
+ case R_CSMODE:
+ if (value > 3) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid csmode %x\n",
+ __func__, value);
+ } else {
+ s->regs[R_CSMODE] = value;
+ sifive_spi_update_cs(s);
+ }
+ break;
+
+ case R_TXDATA:
+ if (!fifo8_is_full(&s->tx_fifo)) {
+ fifo8_push(&s->tx_fifo, (uint8_t)value);
+ sifive_spi_flush_txfifo(s);
+ }
+ break;
+
+ case R_RXDATA:
+ case R_IP:
+ qemu_log_mask(LOG_GUEST_ERROR,
+ "%s: invalid write to read-only reigster 0x%"
+ HWADDR_PRIx " with 0x%x\n", __func__, addr << 2, value);
+ break;
+
+ case R_TXMARK:
+ case R_RXMARK:
+ if (value >= FIFO_CAPACITY) {
+ qemu_log_mask(LOG_GUEST_ERROR, "%s: invalid watermark %d\n",
+ __func__, value);
+ } else {
+ s->regs[addr] = value;
+ }
+ break;
+
+ case R_FCTRL:
+ case R_FFMT:
+ qemu_log_mask(LOG_UNIMP,
+ "%s: direct-map flash interface unimplemented\n",
+ __func__);
+ break;
+
+ default:
+ s->regs[addr] = value;
+ break;
+ }
+
+ sifive_spi_update_irq(s);
+}
+
+static const MemoryRegionOps sifive_spi_ops = {
+ .read = sifive_spi_read,
+ .write = sifive_spi_write,
+ .endianness = DEVICE_LITTLE_ENDIAN,
+ .valid = {
+ .min_access_size = 4,
+ .max_access_size = 4
+ }
+};
+
+static void sifive_spi_realize(DeviceState *dev, Error **errp)
+{
+ SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+ SiFiveSPIState *s = SIFIVE_SPI(dev);
+ int i;
+
+ s->spi = ssi_create_bus(dev, "spi");
+ sysbus_init_irq(sbd, &s->irq);
+
+ s->cs_lines = g_new0(qemu_irq, s->num_cs);
+ for (i = 0; i < s->num_cs; i++) {
+ sysbus_init_irq(sbd, &s->cs_lines[i]);
+ }
+
+ memory_region_init_io(&s->mmio, OBJECT(s), &sifive_spi_ops, s,
+ TYPE_SIFIVE_SPI, 0x1000);
+ sysbus_init_mmio(sbd, &s->mmio);
+
+ fifo8_create(&s->tx_fifo, FIFO_CAPACITY);
+ fifo8_create(&s->rx_fifo, FIFO_CAPACITY);
+}
+
+static Property sifive_spi_properties[] = {
+ DEFINE_PROP_UINT32("num-cs", SiFiveSPIState, num_cs, 1),
+ DEFINE_PROP_END_OF_LIST(),
+};
+
+static void sifive_spi_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+
+ device_class_set_props(dc, sifive_spi_properties);
+ dc->reset = sifive_spi_reset;
+ dc->realize = sifive_spi_realize;
+}
+
+static const TypeInfo sifive_spi_info = {
+ .name = TYPE_SIFIVE_SPI,
+ .parent = TYPE_SYS_BUS_DEVICE,
+ .instance_size = sizeof(SiFiveSPIState),
+ .class_init = sifive_spi_class_init,
+};
+
+static void sifive_spi_register_types(void)
+{
+ type_register_static(&sifive_spi_info);
+}
+
+type_init(sifive_spi_register_types)
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