lm32: add Milkymist HPDMC support

This patch adds support for the Milkymist's High Performance Dynamic Memory
Controller. This is just a dumb model without any functionality. While the
real hardware acts for example as a bridge between software and hardware
for sending SDRAM commans, this model will only eat up these commands and
always returns the expected hardware states, eg. PLL locked etc.

Signed-off-by: Michael Walle <michael@walle.cc>
Signed-off-by: Edgar E. Iglesias <edgar.iglesias@gmail.com>

1 files changed, 161 insertions, 0 deletions

diff --git a/hw/milkymist-hpdmc.c b/hw/milkymist-hpdmc.c
new file mode 100644
index 0000000000..c0962fb528
--- /dev/null
+++ b/hw/milkymist-hpdmc.c
@@ -0,0 +1,161 @@
+/*
+ *  QEMU model of the Milkymist High Performance Dynamic Memory Controller.
+ *
+ *  Copyright (c) 2010 Michael Walle <michael@walle.cc>
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, see <http://www.gnu.org/licenses/>.
+ *
+ *
+ * Specification available at:
+ *   http://www.milkymist.org/socdoc/hpdmc.pdf
+ */
+
+#include "hw.h"
+#include "sysbus.h"
+#include "trace.h"
+#include "qemu-error.h"
+
+enum {
+    R_SYSTEM = 0,
+    R_BYPASS,
+    R_TIMING,
+    R_IODELAY,
+    R_MAX
+};
+
+enum {
+    IODELAY_DQSDELAY_RDY = (1<<5),
+    IODELAY_PLL1_LOCKED  = (1<<6),
+    IODELAY_PLL2_LOCKED  = (1<<7),
+};
+
+struct MilkymistHpdmcState {
+    SysBusDevice busdev;
+
+    uint32_t regs[R_MAX];
+};
+typedef struct MilkymistHpdmcState MilkymistHpdmcState;
+
+static uint32_t hpdmc_read(void *opaque, target_phys_addr_t addr)
+{
+    MilkymistHpdmcState *s = opaque;
+    uint32_t r = 0;
+
+    addr >>= 2;
+    switch (addr) {
+    case R_SYSTEM:
+    case R_BYPASS:
+    case R_TIMING:
+    case R_IODELAY:
+        r = s->regs[addr];
+        break;
+
+    default:
+        error_report("milkymist_hpdmc: read access to unknown register 0x"
+                TARGET_FMT_plx, addr << 2);
+        break;
+    }
+
+    trace_milkymist_hpdmc_memory_read(addr << 2, r);
+
+    return r;
+}
+
+static void hpdmc_write(void *opaque, target_phys_addr_t addr, uint32_t value)
+{
+    MilkymistHpdmcState *s = opaque;
+
+    trace_milkymist_hpdmc_memory_write(addr, value);
+
+    addr >>= 2;
+    switch (addr) {
+    case R_SYSTEM:
+    case R_BYPASS:
+    case R_TIMING:
+        s->regs[addr] = value;
+        break;
+    case R_IODELAY:
+        /* ignore writes */
+        break;
+
+    default:
+        error_report("milkymist_hpdmc: write access to unknown register 0x"
+                TARGET_FMT_plx, addr << 2);
+        break;
+    }
+}
+
+static CPUReadMemoryFunc * const hpdmc_read_fn[] = {
+    NULL,
+    NULL,
+    &hpdmc_read,
+};
+
+static CPUWriteMemoryFunc * const hpdmc_write_fn[] = {
+    NULL,
+    NULL,
+    &hpdmc_write,
+};
+
+static void milkymist_hpdmc_reset(DeviceState *d)
+{
+    MilkymistHpdmcState *s = container_of(d, MilkymistHpdmcState, busdev.qdev);
+    int i;
+
+    for (i = 0; i < R_MAX; i++) {
+        s->regs[i] = 0;
+    }
+
+    /* defaults */
+    s->regs[R_IODELAY] = IODELAY_DQSDELAY_RDY | IODELAY_PLL1_LOCKED
+                         | IODELAY_PLL2_LOCKED;
+}
+
+static int milkymist_hpdmc_init(SysBusDevice *dev)
+{
+    MilkymistHpdmcState *s = FROM_SYSBUS(typeof(*s), dev);
+    int hpdmc_regs;
+
+    hpdmc_regs = cpu_register_io_memory(hpdmc_read_fn, hpdmc_write_fn, s,
+            DEVICE_NATIVE_ENDIAN);
+    sysbus_init_mmio(dev, R_MAX * 4, hpdmc_regs);
+
+    return 0;
+}
+
+static const VMStateDescription vmstate_milkymist_hpdmc = {
+    .name = "milkymist-hpdmc",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields      = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(regs, MilkymistHpdmcState, R_MAX),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static SysBusDeviceInfo milkymist_hpdmc_info = {
+    .init = milkymist_hpdmc_init,
+    .qdev.name  = "milkymist-hpdmc",
+    .qdev.size  = sizeof(MilkymistHpdmcState),
+    .qdev.vmsd  = &vmstate_milkymist_hpdmc,
+    .qdev.reset = milkymist_hpdmc_reset,
+};
+
+static void milkymist_hpdmc_register(void)
+{
+    sysbus_register_withprop(&milkymist_hpdmc_info);
+}
+
+device_init(milkymist_hpdmc_register)