summaryrefslogtreecommitdiff
path: root/hw/sd/milkymist-memcard.c
diff options
context:
space:
mode:
Diffstat (limited to 'hw/sd/milkymist-memcard.c')
-rw-r--r--hw/sd/milkymist-memcard.c303
1 files changed, 303 insertions, 0 deletions
diff --git a/hw/sd/milkymist-memcard.c b/hw/sd/milkymist-memcard.c
new file mode 100644
index 0000000000..d5944bca69
--- /dev/null
+++ b/hw/sd/milkymist-memcard.c
@@ -0,0 +1,303 @@
+/*
+ * QEMU model of the Milkymist SD Card 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/memcard.pdf
+ */
+
+#include "hw/hw.h"
+#include "hw/sysbus.h"
+#include "sysemu/sysemu.h"
+#include "trace.h"
+#include "qemu/error-report.h"
+#include "sysemu/blockdev.h"
+#include "hw/sd.h"
+
+enum {
+ ENABLE_CMD_TX = (1<<0),
+ ENABLE_CMD_RX = (1<<1),
+ ENABLE_DAT_TX = (1<<2),
+ ENABLE_DAT_RX = (1<<3),
+};
+
+enum {
+ PENDING_CMD_TX = (1<<0),
+ PENDING_CMD_RX = (1<<1),
+ PENDING_DAT_TX = (1<<2),
+ PENDING_DAT_RX = (1<<3),
+};
+
+enum {
+ START_CMD_TX = (1<<0),
+ START_DAT_RX = (1<<1),
+};
+
+enum {
+ R_CLK2XDIV = 0,
+ R_ENABLE,
+ R_PENDING,
+ R_START,
+ R_CMD,
+ R_DAT,
+ R_MAX
+};
+
+struct MilkymistMemcardState {
+ SysBusDevice busdev;
+ MemoryRegion regs_region;
+ SDState *card;
+
+ int command_write_ptr;
+ int response_read_ptr;
+ int response_len;
+ int ignore_next_cmd;
+ int enabled;
+ uint8_t command[6];
+ uint8_t response[17];
+ uint32_t regs[R_MAX];
+};
+typedef struct MilkymistMemcardState MilkymistMemcardState;
+
+static void update_pending_bits(MilkymistMemcardState *s)
+{
+ /* transmits are instantaneous, thus tx pending bits are never set */
+ s->regs[R_PENDING] = 0;
+ /* if rx is enabled the corresponding pending bits are always set */
+ if (s->regs[R_ENABLE] & ENABLE_CMD_RX) {
+ s->regs[R_PENDING] |= PENDING_CMD_RX;
+ }
+ if (s->regs[R_ENABLE] & ENABLE_DAT_RX) {
+ s->regs[R_PENDING] |= PENDING_DAT_RX;
+ }
+}
+
+static void memcard_sd_command(MilkymistMemcardState *s)
+{
+ SDRequest req;
+
+ req.cmd = s->command[0] & 0x3f;
+ req.arg = (s->command[1] << 24) | (s->command[2] << 16)
+ | (s->command[3] << 8) | s->command[4];
+ req.crc = s->command[5];
+
+ s->response[0] = req.cmd;
+ s->response_len = sd_do_command(s->card, &req, s->response+1);
+ s->response_read_ptr = 0;
+
+ if (s->response_len == 16) {
+ /* R2 response */
+ s->response[0] = 0x3f;
+ s->response_len += 1;
+ } else if (s->response_len == 4) {
+ /* no crc calculation, insert dummy byte */
+ s->response[5] = 0;
+ s->response_len += 2;
+ }
+
+ if (req.cmd == 0) {
+ /* next write is a dummy byte to clock the initialization of the sd
+ * card */
+ s->ignore_next_cmd = 1;
+ }
+}
+
+static uint64_t memcard_read(void *opaque, hwaddr addr,
+ unsigned size)
+{
+ MilkymistMemcardState *s = opaque;
+ uint32_t r = 0;
+
+ addr >>= 2;
+ switch (addr) {
+ case R_CMD:
+ if (!s->enabled) {
+ r = 0xff;
+ } else {
+ r = s->response[s->response_read_ptr++];
+ if (s->response_read_ptr > s->response_len) {
+ error_report("milkymist_memcard: "
+ "read more cmd bytes than available. Clipping.");
+ s->response_read_ptr = 0;
+ }
+ }
+ break;
+ case R_DAT:
+ if (!s->enabled) {
+ r = 0xffffffff;
+ } else {
+ r = 0;
+ r |= sd_read_data(s->card) << 24;
+ r |= sd_read_data(s->card) << 16;
+ r |= sd_read_data(s->card) << 8;
+ r |= sd_read_data(s->card);
+ }
+ break;
+ case R_CLK2XDIV:
+ case R_ENABLE:
+ case R_PENDING:
+ case R_START:
+ r = s->regs[addr];
+ break;
+
+ default:
+ error_report("milkymist_memcard: read access to unknown register 0x"
+ TARGET_FMT_plx, addr << 2);
+ break;
+ }
+
+ trace_milkymist_memcard_memory_read(addr << 2, r);
+
+ return r;
+}
+
+static void memcard_write(void *opaque, hwaddr addr, uint64_t value,
+ unsigned size)
+{
+ MilkymistMemcardState *s = opaque;
+
+ trace_milkymist_memcard_memory_write(addr, value);
+
+ addr >>= 2;
+ switch (addr) {
+ case R_PENDING:
+ /* clear rx pending bits */
+ s->regs[R_PENDING] &= ~(value & (PENDING_CMD_RX | PENDING_DAT_RX));
+ update_pending_bits(s);
+ break;
+ case R_CMD:
+ if (!s->enabled) {
+ break;
+ }
+ if (s->ignore_next_cmd) {
+ s->ignore_next_cmd = 0;
+ break;
+ }
+ s->command[s->command_write_ptr] = value & 0xff;
+ s->command_write_ptr = (s->command_write_ptr + 1) % 6;
+ if (s->command_write_ptr == 0) {
+ memcard_sd_command(s);
+ }
+ break;
+ case R_DAT:
+ if (!s->enabled) {
+ break;
+ }
+ sd_write_data(s->card, (value >> 24) & 0xff);
+ sd_write_data(s->card, (value >> 16) & 0xff);
+ sd_write_data(s->card, (value >> 8) & 0xff);
+ sd_write_data(s->card, value & 0xff);
+ break;
+ case R_ENABLE:
+ s->regs[addr] = value;
+ update_pending_bits(s);
+ break;
+ case R_CLK2XDIV:
+ case R_START:
+ s->regs[addr] = value;
+ break;
+
+ default:
+ error_report("milkymist_memcard: write access to unknown register 0x"
+ TARGET_FMT_plx, addr << 2);
+ break;
+ }
+}
+
+static const MemoryRegionOps memcard_mmio_ops = {
+ .read = memcard_read,
+ .write = memcard_write,
+ .valid = {
+ .min_access_size = 4,
+ .max_access_size = 4,
+ },
+ .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static void milkymist_memcard_reset(DeviceState *d)
+{
+ MilkymistMemcardState *s =
+ container_of(d, MilkymistMemcardState, busdev.qdev);
+ int i;
+
+ s->command_write_ptr = 0;
+ s->response_read_ptr = 0;
+ s->response_len = 0;
+
+ for (i = 0; i < R_MAX; i++) {
+ s->regs[i] = 0;
+ }
+}
+
+static int milkymist_memcard_init(SysBusDevice *dev)
+{
+ MilkymistMemcardState *s = FROM_SYSBUS(typeof(*s), dev);
+ DriveInfo *dinfo;
+
+ dinfo = drive_get_next(IF_SD);
+ s->card = sd_init(dinfo ? dinfo->bdrv : NULL, 0);
+ s->enabled = dinfo ? bdrv_is_inserted(dinfo->bdrv) : 0;
+
+ memory_region_init_io(&s->regs_region, &memcard_mmio_ops, s,
+ "milkymist-memcard", R_MAX * 4);
+ sysbus_init_mmio(dev, &s->regs_region);
+
+ return 0;
+}
+
+static const VMStateDescription vmstate_milkymist_memcard = {
+ .name = "milkymist-memcard",
+ .version_id = 1,
+ .minimum_version_id = 1,
+ .minimum_version_id_old = 1,
+ .fields = (VMStateField[]) {
+ VMSTATE_INT32(command_write_ptr, MilkymistMemcardState),
+ VMSTATE_INT32(response_read_ptr, MilkymistMemcardState),
+ VMSTATE_INT32(response_len, MilkymistMemcardState),
+ VMSTATE_INT32(ignore_next_cmd, MilkymistMemcardState),
+ VMSTATE_INT32(enabled, MilkymistMemcardState),
+ VMSTATE_UINT8_ARRAY(command, MilkymistMemcardState, 6),
+ VMSTATE_UINT8_ARRAY(response, MilkymistMemcardState, 17),
+ VMSTATE_UINT32_ARRAY(regs, MilkymistMemcardState, R_MAX),
+ VMSTATE_END_OF_LIST()
+ }
+};
+
+static void milkymist_memcard_class_init(ObjectClass *klass, void *data)
+{
+ DeviceClass *dc = DEVICE_CLASS(klass);
+ SysBusDeviceClass *k = SYS_BUS_DEVICE_CLASS(klass);
+
+ k->init = milkymist_memcard_init;
+ dc->reset = milkymist_memcard_reset;
+ dc->vmsd = &vmstate_milkymist_memcard;
+}
+
+static const TypeInfo milkymist_memcard_info = {
+ .name = "milkymist-memcard",
+ .parent = TYPE_SYS_BUS_DEVICE,
+ .instance_size = sizeof(MilkymistMemcardState),
+ .class_init = milkymist_memcard_class_init,
+};
+
+static void milkymist_memcard_register_types(void)
+{
+ type_register_static(&milkymist_memcard_info);
+}
+
+type_init(milkymist_memcard_register_types)
generated by cgit v1.2.3 (git 2.39.1) at 2024-12-02 11:29:41 +0000