hw/dma: Add SiFive platform DMA controller emulation

Microchip PolarFire SoC integrates a DMA engine that supports:
* Independent concurrent DMA transfers using 4 DMA channels
* Generation of interrupts on various conditions during execution
which is actually an IP reused from the SiFive FU540 chip.

This creates a model to support both polling and interrupt modes.

Signed-off-by: Bin Meng <bin.meng@windriver.com>
Acked-by: Alistair Francis <alistair.francis@wdc.com>
Message-Id: <1598924352-89526-10-git-send-email-bmeng.cn@gmail.com>
Signed-off-by: Alistair Francis <alistair.francis@wdc.com>

3 files changed, 317 insertions, 0 deletions

diff --git a/hw/dma/Kconfig b/hw/dma/Kconfig
index 5c61b67bc0..d67492d36c 100644
--- a/hw/dma/Kconfig
+++ b/hw/dma/Kconfig
@@ -20,3 +20,6 @@ config ZYNQ_DEVCFG
 
 config STP2000
     bool
+
+config SIFIVE_PDMA
+    bool
diff --git a/hw/dma/meson.build b/hw/dma/meson.build
index ff5bb3748f..b991d7698c 100644
--- a/hw/dma/meson.build
+++ b/hw/dma/meson.build
@@ -13,3 +13,4 @@ softmmu_ss.add(when: 'CONFIG_XLNX_ZYNQMP_ARM', if_true: files('xlnx-zdma.c'))
 softmmu_ss.add(when: 'CONFIG_OMAP', if_true: files('omap_dma.c', 'soc_dma.c'))
 softmmu_ss.add(when: 'CONFIG_PXA2XX', if_true: files('pxa2xx_dma.c'))
 softmmu_ss.add(when: 'CONFIG_RASPI', if_true: files('bcm2835_dma.c'))
+softmmu_ss.add(when: 'CONFIG_SIFIVE_PDMA', if_true: files('sifive_pdma.c'))
diff --git a/hw/dma/sifive_pdma.c b/hw/dma/sifive_pdma.c
new file mode 100644
index 0000000000..e1f6fedbda
--- /dev/null
+++ b/hw/dma/sifive_pdma.c
@@ -0,0 +1,313 @@
+/*
+ * SiFive Platform DMA emulation
+ *
+ * Copyright (c) 2020 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 of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 or
+ * (at your option) version 3 of the License.
+ *
+ * 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 "qemu/osdep.h"
+#include "qemu/bitops.h"
+#include "qemu/log.h"
+#include "qapi/error.h"
+#include "hw/hw.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "hw/sysbus.h"
+#include "migration/vmstate.h"
+#include "sysemu/dma.h"
+#include "hw/dma/sifive_pdma.h"
+
+#define DMA_CONTROL         0x000
+#define   CONTROL_CLAIM     BIT(0)
+#define   CONTROL_RUN       BIT(1)
+#define   CONTROL_DONE_IE   BIT(14)
+#define   CONTROL_ERR_IE    BIT(15)
+#define   CONTROL_DONE      BIT(30)
+#define   CONTROL_ERR       BIT(31)
+
+#define DMA_NEXT_CONFIG     0x004
+#define   CONFIG_REPEAT     BIT(2)
+#define   CONFIG_ORDER      BIT(3)
+#define   CONFIG_WRSZ_SHIFT 24
+#define   CONFIG_RDSZ_SHIFT 28
+#define   CONFIG_SZ_MASK    0xf
+
+#define DMA_NEXT_BYTES      0x008
+#define DMA_NEXT_DST        0x010
+#define DMA_NEXT_SRC        0x018
+#define DMA_EXEC_CONFIG     0x104
+#define DMA_EXEC_BYTES      0x108
+#define DMA_EXEC_DST        0x110
+#define DMA_EXEC_SRC        0x118
+
+enum dma_chan_state {
+    DMA_CHAN_STATE_IDLE,
+    DMA_CHAN_STATE_STARTED,
+    DMA_CHAN_STATE_ERROR,
+    DMA_CHAN_STATE_DONE
+};
+
+static void sifive_pdma_run(SiFivePDMAState *s, int ch)
+{
+    uint64_t bytes = s->chan[ch].next_bytes;
+    uint64_t dst = s->chan[ch].next_dst;
+    uint64_t src = s->chan[ch].next_src;
+    uint32_t config = s->chan[ch].next_config;
+    int wsize, rsize, size;
+    uint8_t buf[64];
+    int n;
+
+    /* do nothing if bytes to transfer is zero */
+    if (!bytes) {
+        goto error;
+    }
+
+    /*
+     * The manual does not describe how the hardware behaviors when
+     * config.wsize and config.rsize are given different values.
+     * A common case is memory to memory DMA, and in this case they
+     * are normally the same. Abort if this expectation fails.
+     */
+    wsize = (config >> CONFIG_WRSZ_SHIFT) & CONFIG_SZ_MASK;
+    rsize = (config >> CONFIG_RDSZ_SHIFT) & CONFIG_SZ_MASK;
+    if (wsize != rsize) {
+        goto error;
+    }
+
+    /*
+     * Calculate the transaction size
+     *
+     * size field is base 2 logarithm of DMA transaction size,
+     * but there is an upper limit of 64 bytes per transaction.
+     */
+    size = wsize;
+    if (size > 6) {
+        size = 6;
+    }
+    size = 1 << size;
+
+    /* the bytes to transfer should be multiple of transaction size */
+    if (bytes % size) {
+        goto error;
+    }
+
+    /* indicate a DMA transfer is started */
+    s->chan[ch].state = DMA_CHAN_STATE_STARTED;
+    s->chan[ch].control &= ~CONTROL_DONE;
+    s->chan[ch].control &= ~CONTROL_ERR;
+
+    /* load the next_ registers into their exec_ counterparts */
+    s->chan[ch].exec_config = config;
+    s->chan[ch].exec_bytes = bytes;
+    s->chan[ch].exec_dst = dst;
+    s->chan[ch].exec_src = src;
+
+    for (n = 0; n < bytes / size; n++) {
+        cpu_physical_memory_read(s->chan[ch].exec_src, buf, size);
+        cpu_physical_memory_write(s->chan[ch].exec_dst, buf, size);
+        s->chan[ch].exec_src += size;
+        s->chan[ch].exec_dst += size;
+        s->chan[ch].exec_bytes -= size;
+    }
+
+    /* indicate a DMA transfer is done */
+    s->chan[ch].state = DMA_CHAN_STATE_DONE;
+    s->chan[ch].control &= ~CONTROL_RUN;
+    s->chan[ch].control |= CONTROL_DONE;
+
+    /* reload exec_ registers if repeat is required */
+    if (s->chan[ch].next_config & CONFIG_REPEAT) {
+        s->chan[ch].exec_bytes = bytes;
+        s->chan[ch].exec_dst = dst;
+        s->chan[ch].exec_src = src;
+    }
+
+    return;
+
+error:
+    s->chan[ch].state = DMA_CHAN_STATE_ERROR;
+    s->chan[ch].control |= CONTROL_ERR;
+    return;
+}
+
+static inline void sifive_pdma_update_irq(SiFivePDMAState *s, int ch)
+{
+    bool done_ie, err_ie;
+
+    done_ie = !!(s->chan[ch].control & CONTROL_DONE_IE);
+    err_ie = !!(s->chan[ch].control & CONTROL_ERR_IE);
+
+    if (done_ie && (s->chan[ch].control & CONTROL_DONE)) {
+        qemu_irq_raise(s->irq[ch * 2]);
+    } else {
+        qemu_irq_lower(s->irq[ch * 2]);
+    }
+
+    if (err_ie && (s->chan[ch].control & CONTROL_ERR)) {
+        qemu_irq_raise(s->irq[ch * 2 + 1]);
+    } else {
+        qemu_irq_lower(s->irq[ch * 2 + 1]);
+    }
+
+    s->chan[ch].state = DMA_CHAN_STATE_IDLE;
+}
+
+static uint64_t sifive_pdma_read(void *opaque, hwaddr offset, unsigned size)
+{
+    SiFivePDMAState *s = opaque;
+    int ch = SIFIVE_PDMA_CHAN_NO(offset);
+    uint64_t val = 0;
+
+    if (ch >= SIFIVE_PDMA_CHANS) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Invalid channel no %d\n",
+                      __func__, ch);
+        return 0;
+    }
+
+    offset &= 0xfff;
+    switch (offset) {
+    case DMA_CONTROL:
+        val = s->chan[ch].control;
+        break;
+    case DMA_NEXT_CONFIG:
+        val = s->chan[ch].next_config;
+        break;
+    case DMA_NEXT_BYTES:
+        val = s->chan[ch].next_bytes;
+        break;
+    case DMA_NEXT_DST:
+        val = s->chan[ch].next_dst;
+        break;
+    case DMA_NEXT_SRC:
+        val = s->chan[ch].next_src;
+        break;
+    case DMA_EXEC_CONFIG:
+        val = s->chan[ch].exec_config;
+        break;
+    case DMA_EXEC_BYTES:
+        val = s->chan[ch].exec_bytes;
+        break;
+    case DMA_EXEC_DST:
+        val = s->chan[ch].exec_dst;
+        break;
+    case DMA_EXEC_SRC:
+        val = s->chan[ch].exec_src;
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%" HWADDR_PRIX "\n",
+                      __func__, offset);
+        break;
+    }
+
+    return val;
+}
+
+static void sifive_pdma_write(void *opaque, hwaddr offset,
+                              uint64_t value, unsigned size)
+{
+    SiFivePDMAState *s = opaque;
+    int ch = SIFIVE_PDMA_CHAN_NO(offset);
+
+    if (ch >= SIFIVE_PDMA_CHANS) {
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Invalid channel no %d\n",
+                      __func__, ch);
+        return;
+    }
+
+    offset &= 0xfff;
+    switch (offset) {
+    case DMA_CONTROL:
+        s->chan[ch].control = value;
+
+        if (value & CONTROL_RUN) {
+            sifive_pdma_run(s, ch);
+        }
+
+        sifive_pdma_update_irq(s, ch);
+        break;
+    case DMA_NEXT_CONFIG:
+        s->chan[ch].next_config = value;
+        break;
+    case DMA_NEXT_BYTES:
+        s->chan[ch].next_bytes = value;
+        break;
+    case DMA_NEXT_DST:
+        s->chan[ch].next_dst = value;
+        break;
+    case DMA_NEXT_SRC:
+        s->chan[ch].next_src = value;
+        break;
+    case DMA_EXEC_CONFIG:
+    case DMA_EXEC_BYTES:
+    case DMA_EXEC_DST:
+    case DMA_EXEC_SRC:
+        /* these are read-only registers */
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad offset 0x%" HWADDR_PRIX "\n",
+                      __func__, offset);
+        break;
+    }
+}
+
+static const MemoryRegionOps sifive_pdma_ops = {
+    .read = sifive_pdma_read,
+    .write = sifive_pdma_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    /* there are 32-bit and 64-bit wide registers */
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 8,
+    }
+};
+
+static void sifive_pdma_realize(DeviceState *dev, Error **errp)
+{
+    SiFivePDMAState *s = SIFIVE_PDMA(dev);
+    int i;
+
+    memory_region_init_io(&s->iomem, OBJECT(dev), &sifive_pdma_ops, s,
+                          TYPE_SIFIVE_PDMA, SIFIVE_PDMA_REG_SIZE);
+    sysbus_init_mmio(SYS_BUS_DEVICE(dev), &s->iomem);
+
+    for (i = 0; i < SIFIVE_PDMA_IRQS; i++) {
+        sysbus_init_irq(SYS_BUS_DEVICE(dev), &s->irq[i]);
+    }
+}
+
+static void sifive_pdma_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->desc = "SiFive Platform DMA controller";
+    dc->realize = sifive_pdma_realize;
+}
+
+static const TypeInfo sifive_pdma_info = {
+    .name          = TYPE_SIFIVE_PDMA,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(SiFivePDMAState),
+    .class_init    = sifive_pdma_class_init,
+};
+
+static void sifive_pdma_register_types(void)
+{
+    type_register_static(&sifive_pdma_info);
+}
+
+type_init(sifive_pdma_register_types)