hw/milkymist-memcard.c - qemu - Git at Google

 /*
  *  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.h"
 #include "sysbus.h"
 #include "sysemu/sysemu.h"
 #include "trace.h"
 #include "qemu/error-report.h"
 #include "sysemu/blockdev.h"
 #include "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 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)
	/*
	* 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.h"
	#include "sysbus.h"
	#include "sysemu/sysemu.h"
	#include "trace.h"
	#include "qemu/error-report.h"
	#include "sysemu/blockdev.h"
	#include "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 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)