hw/misc: Allwinner A10 DRAM Controller Emulation

During SPL boot several DRAM Controller registers are used. Most
important registers are those related to DRAM initialization and
calibration, where SPL initiates process and waits until certain bit is
set/cleared.

This patch adds these registers, initializes reset values from user's
guide and updates state of registers as SPL expects it.

Signed-off-by: Strahinja Jankovic <strahinja.p.jankovic@gmail.com>

Reviewed-by: Niek Linnenbank <nieklinnenbank@gmail.com>
Message-id: 20221226220303.14420-3-strahinja.p.jankovic@gmail.com
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 183 insertions, 0 deletions

diff --git a/hw/misc/Kconfig b/hw/misc/Kconfig
index ed07bf4..052fb54 100644
--- a/hw/misc/Kconfig
+++ b/hw/misc/Kconfig
@@ -177,4 +177,7 @@ config LASI
 config ALLWINNER_A10_CCM
     bool
 
+config ALLWINNER_A10_DRAMC
+    bool
+
 source macio/Kconfig
diff --git a/hw/misc/allwinner-a10-dramc.c b/hw/misc/allwinner-a10-dramc.c
new file mode 100644
index 0000000..e118b0c
--- /dev/null
+++ b/hw/misc/allwinner-a10-dramc.c
@@ -0,0 +1,179 @@
+/*
+ * Allwinner A10 DRAM Controller emulation
+ *
+ * Copyright (C) 2022 Strahinja Jankovic <strahinja.p.jankovic@gmail.com>
+ *
+ *  This file is derived from Allwinner H3 DRAMC,
+ *  by Niek Linnenbank.
+ *
+ * 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 of the License, or
+ * (at your option) any later version.
+ *
+ * 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/units.h"
+#include "hw/sysbus.h"
+#include "migration/vmstate.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "hw/misc/allwinner-a10-dramc.h"
+
+/* DRAMC register offsets */
+enum {
+    REG_SDR_CCR = 0x0000,
+    REG_SDR_ZQCR0 = 0x00a8,
+    REG_SDR_ZQSR = 0x00b0
+};
+
+#define REG_INDEX(offset)    (offset / sizeof(uint32_t))
+
+/* DRAMC register flags */
+enum {
+    REG_SDR_CCR_DATA_TRAINING = (1 << 30),
+    REG_SDR_CCR_DRAM_INIT     = (1 << 31),
+};
+enum {
+    REG_SDR_ZQSR_ZCAL         = (1 << 31),
+};
+
+/* DRAMC register reset values */
+enum {
+    REG_SDR_CCR_RESET   = 0x80020000,
+    REG_SDR_ZQCR0_RESET = 0x07b00000,
+    REG_SDR_ZQSR_RESET  = 0x80000000
+};
+
+static uint64_t allwinner_a10_dramc_read(void *opaque, hwaddr offset,
+                                       unsigned size)
+{
+    const AwA10DramControllerState *s = AW_A10_DRAMC(opaque);
+    const uint32_t idx = REG_INDEX(offset);
+
+    switch (offset) {
+    case REG_SDR_CCR:
+    case REG_SDR_ZQCR0:
+    case REG_SDR_ZQSR:
+        break;
+    case 0x2e4 ... AW_A10_DRAMC_IOSIZE:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: out-of-bounds offset 0x%04x\n",
+                      __func__, (uint32_t)offset);
+        return 0;
+    default:
+        qemu_log_mask(LOG_UNIMP, "%s: unimplemented read offset 0x%04x\n",
+                      __func__, (uint32_t)offset);
+        return 0;
+    }
+
+    return s->regs[idx];
+}
+
+static void allwinner_a10_dramc_write(void *opaque, hwaddr offset,
+                                   uint64_t val, unsigned size)
+{
+    AwA10DramControllerState *s = AW_A10_DRAMC(opaque);
+    const uint32_t idx = REG_INDEX(offset);
+
+    switch (offset) {
+    case REG_SDR_CCR:
+        if (val & REG_SDR_CCR_DRAM_INIT) {
+            /* Clear DRAM_INIT to indicate process is done. */
+            val &= ~REG_SDR_CCR_DRAM_INIT;
+        }
+        if (val & REG_SDR_CCR_DATA_TRAINING) {
+            /* Clear DATA_TRAINING to indicate process is done. */
+            val &= ~REG_SDR_CCR_DATA_TRAINING;
+        }
+        break;
+    case REG_SDR_ZQCR0:
+        /* Set ZCAL in ZQSR to indicate calibration is done. */
+        s->regs[REG_INDEX(REG_SDR_ZQSR)] |= REG_SDR_ZQSR_ZCAL;
+        break;
+    case 0x2e4 ... AW_A10_DRAMC_IOSIZE:
+        qemu_log_mask(LOG_GUEST_ERROR, "%s: out-of-bounds offset 0x%04x\n",
+                      __func__, (uint32_t)offset);
+        break;
+    default:
+        qemu_log_mask(LOG_UNIMP, "%s: unimplemented write offset 0x%04x\n",
+                      __func__, (uint32_t)offset);
+        break;
+    }
+
+    s->regs[idx] = (uint32_t) val;
+}
+
+static const MemoryRegionOps allwinner_a10_dramc_ops = {
+    .read = allwinner_a10_dramc_read,
+    .write = allwinner_a10_dramc_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+    },
+    .impl.min_access_size = 4,
+};
+
+static void allwinner_a10_dramc_reset_enter(Object *obj, ResetType type)
+{
+    AwA10DramControllerState *s = AW_A10_DRAMC(obj);
+
+    /* Set default values for registers */
+    s->regs[REG_INDEX(REG_SDR_CCR)] = REG_SDR_CCR_RESET;
+    s->regs[REG_INDEX(REG_SDR_ZQCR0)] = REG_SDR_ZQCR0_RESET;
+    s->regs[REG_INDEX(REG_SDR_ZQSR)] = REG_SDR_ZQSR_RESET;
+}
+
+static void allwinner_a10_dramc_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    AwA10DramControllerState *s = AW_A10_DRAMC(obj);
+
+    /* Memory mapping */
+    memory_region_init_io(&s->iomem, OBJECT(s), &allwinner_a10_dramc_ops, s,
+                          TYPE_AW_A10_DRAMC, AW_A10_DRAMC_IOSIZE);
+    sysbus_init_mmio(sbd, &s->iomem);
+}
+
+static const VMStateDescription allwinner_a10_dramc_vmstate = {
+    .name = "allwinner-a10-dramc",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(regs, AwA10DramControllerState,
+                             AW_A10_DRAMC_REGS_NUM),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void allwinner_a10_dramc_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
+
+    rc->phases.enter = allwinner_a10_dramc_reset_enter;
+    dc->vmsd = &allwinner_a10_dramc_vmstate;
+}
+
+static const TypeInfo allwinner_a10_dramc_info = {
+    .name          = TYPE_AW_A10_DRAMC,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_init = allwinner_a10_dramc_init,
+    .instance_size = sizeof(AwA10DramControllerState),
+    .class_init    = allwinner_a10_dramc_class_init,
+};
+
+static void allwinner_a10_dramc_register(void)
+{
+    type_register_static(&allwinner_a10_dramc_info);
+}
+
+type_init(allwinner_a10_dramc_register)
diff --git a/hw/misc/meson.build b/hw/misc/meson.build
index c828dbe..9eaa075 100644
--- a/hw/misc/meson.build
+++ b/hw/misc/meson.build
@@ -39,6 +39,7 @@ subdir('macio')
 softmmu_ss.add(when: 'CONFIG_IVSHMEM_DEVICE', if_true: files('ivshmem.c'))
 
 softmmu_ss.add(when: 'CONFIG_ALLWINNER_A10_CCM', if_true: files('allwinner-a10-ccm.c'))
+softmmu_ss.add(when: 'CONFIG_ALLWINNER_A10_DRAMC', if_true: files('allwinner-a10-dramc.c'))
 softmmu_ss.add(when: 'CONFIG_ALLWINNER_H3', if_true: files('allwinner-h3-ccu.c'))
 specific_ss.add(when: 'CONFIG_ALLWINNER_H3', if_true: files('allwinner-cpucfg.c'))
 softmmu_ss.add(when: 'CONFIG_ALLWINNER_H3', if_true: files('allwinner-h3-dramc.c'))