/*
* 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)
