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qemu-e2k/hw/i2c/pm_smbus.c
Philippe Mathieu-Daudé 00d1d29b76 hw/i2c/pm_smbus: Remove dead assignment 
Fix warning reported by Clang static code analyzer:

    CC      hw/i2c/pm_smbus.o
  hw/i2c/pm_smbus.c:187:17: warning: Value stored to 'ret' is never read
                  ret = 0;
                  ^     ~

Reported-by: Clang Static Analyzer
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Signed-off-by: Philippe Mathieu-Daudé <philmd@redhat.com>
Message-Id: <20200422133152.16770-4-philmd@redhat.com>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
2020-05-04 14:43:24 +02:00

498 lines
14 KiB
C
Raw Blame History

/*
* PC SMBus implementation
* splitted from acpi.c
*
* Copyright (c) 2006 Fabrice Bellard
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License version 2 as published by the Free Software Foundation.
*
* 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/>.
*/
#include "qemu/osdep.h"
#include "hw/boards.h"
#include "hw/i2c/pm_smbus.h"
#include "hw/i2c/smbus_master.h"
#include "migration/vmstate.h"
#define SMBHSTSTS 0x00
#define SMBHSTCNT 0x02
#define SMBHSTCMD 0x03
#define SMBHSTADD 0x04
#define SMBHSTDAT0 0x05
#define SMBHSTDAT1 0x06
#define SMBBLKDAT 0x07
#define SMBAUXCTL 0x0d
#define STS_HOST_BUSY (1 << 0)
#define STS_INTR (1 << 1)
#define STS_DEV_ERR (1 << 2)
#define STS_BUS_ERR (1 << 3)
#define STS_FAILED (1 << 4)
#define STS_SMBALERT (1 << 5)
#define STS_INUSE_STS (1 << 6)
#define STS_BYTE_DONE (1 << 7)
/* Signs of successfully transaction end :
* ByteDoneStatus = 1 (STS_BYTE_DONE) and INTR = 1 (STS_INTR )
*/
#define CTL_INTREN (1 << 0)
#define CTL_KILL (1 << 1)
#define CTL_LAST_BYTE (1 << 5)
#define CTL_START (1 << 6)
#define CTL_PEC_EN (1 << 7)
#define CTL_RETURN_MASK 0x1f
#define PROT_QUICK 0
#define PROT_BYTE 1
#define PROT_BYTE_DATA 2
#define PROT_WORD_DATA 3
#define PROT_PROC_CALL 4
#define PROT_BLOCK_DATA 5
#define PROT_I2C_BLOCK_READ 6
#define AUX_PEC (1 << 0)
#define AUX_BLK (1 << 1)
#define AUX_MASK 0x3
/*#define DEBUG*/
#ifdef DEBUG
# define SMBUS_DPRINTF(format, ...) printf(format, ## __VA_ARGS__)
#else
# define SMBUS_DPRINTF(format, ...) do { } while (0)
#endif
static void smb_transaction(PMSMBus *s)
{
uint8_t prot = (s->smb_ctl >> 2) & 0x07;
uint8_t read = s->smb_addr & 0x01;
uint8_t cmd = s->smb_cmd;
uint8_t addr = s->smb_addr >> 1;
I2CBus *bus = s->smbus;
int ret;
SMBUS_DPRINTF("SMBus trans addr=0x%02x prot=0x%02x\n", addr, prot);
/* Transaction isn't exec if STS_DEV_ERR bit set */
if ((s->smb_stat & STS_DEV_ERR) != 0) {
goto error;
}
switch(prot) {
case PROT_QUICK:
ret = smbus_quick_command(bus, addr, read);
goto done;
case PROT_BYTE:
if (read) {
ret = smbus_receive_byte(bus, addr);
goto data8;
} else {
ret = smbus_send_byte(bus, addr, cmd);
goto done;
}
case PROT_BYTE_DATA:
if (read) {
ret = smbus_read_byte(bus, addr, cmd);
goto data8;
} else {
ret = smbus_write_byte(bus, addr, cmd, s->smb_data0);
goto done;
}
break;
case PROT_WORD_DATA:
if (read) {
ret = smbus_read_word(bus, addr, cmd);
goto data16;
} else {
ret = smbus_write_word(bus, addr, cmd,
(s->smb_data1 << 8) | s->smb_data0);
goto done;
}
break;
case PROT_I2C_BLOCK_READ:
/* According to the Linux i2c-i801 driver:
* NB: page 240 of ICH5 datasheet shows that the R/#W
* bit should be cleared here, even when reading.
* However if SPD Write Disable is set (Lynx Point and later),
* the read will fail if we don't set the R/#W bit.
* So at least Linux may or may not set the read bit here.
* So just ignore the read bit for this command.
*/
if (i2c_start_transfer(bus, addr, 0)) {
goto error;
}
ret = i2c_send(bus, s->smb_data1);
if (ret) {
goto error;
}
if (i2c_start_transfer(bus, addr, 1)) {
goto error;
}
s->in_i2c_block_read = true;
s->smb_blkdata = i2c_recv(s->smbus);
s->op_done = false;
s->smb_stat |= STS_HOST_BUSY | STS_BYTE_DONE;
goto out;
case PROT_BLOCK_DATA:
if (read) {
ret = smbus_read_block(bus, addr, cmd, s->smb_data,
sizeof(s->smb_data), !s->i2c_enable,
!s->i2c_enable);
if (ret < 0) {
goto error;
}
s->smb_index = 0;
s->op_done = false;
if (s->smb_auxctl & AUX_BLK) {
s->smb_stat |= STS_INTR;
} else {
s->smb_blkdata = s->smb_data[0];
s->smb_stat |= STS_HOST_BUSY | STS_BYTE_DONE;
}
s->smb_data0 = ret;
goto out;
} else {
if (s->smb_auxctl & AUX_BLK) {
if (s->smb_index != s->smb_data0) {
s->smb_index = 0;
goto error;
}
/* Data is already all written to the queue, just do
the operation. */
s->smb_index = 0;
ret = smbus_write_block(bus, addr, cmd, s->smb_data,
s->smb_data0, !s->i2c_enable);
if (ret < 0) {
goto error;
}
s->op_done = true;
s->smb_stat |= STS_INTR;
s->smb_stat &= ~STS_HOST_BUSY;
} else {
s->op_done = false;
s->smb_stat |= STS_HOST_BUSY | STS_BYTE_DONE;
s->smb_data[0] = s->smb_blkdata;
s->smb_index = 0;
}
goto out;
}
break;
default:
goto error;
}
abort();
data16:
if (ret < 0) {
goto error;
}
s->smb_data1 = ret >> 8;
data8:
if (ret < 0) {
goto error;
}
s->smb_data0 = ret;
done:
if (ret < 0) {
goto error;
}
s->smb_stat |= STS_INTR;
out:
return;
error:
s->smb_stat |= STS_DEV_ERR;
return;
}
static void smb_transaction_start(PMSMBus *s)
{
if (s->smb_ctl & CTL_INTREN) {
smb_transaction(s);
s->start_transaction_on_status_read = false;
} else {
/* Do not execute immediately the command; it will be
* executed when guest will read SMB_STAT register. This
* is to work around a bug in AMIBIOS (that is working
* around another bug in some specific hardware) where
* it waits for STS_HOST_BUSY to be set before waiting
* checking for status. If STS_HOST_BUSY doesn't get
* set, it gets stuck. */
s->smb_stat |= STS_HOST_BUSY;
s->start_transaction_on_status_read = true;
}
}
static bool
smb_irq_value(PMSMBus *s)
{
return ((s->smb_stat & ~STS_HOST_BUSY) != 0) && (s->smb_ctl & CTL_INTREN);
}
static bool
smb_byte_by_byte(PMSMBus *s)
{
if (s->op_done) {
return false;
}
if (s->in_i2c_block_read) {
return true;
}
return !(s->smb_auxctl & AUX_BLK);
}
static void smb_ioport_writeb(void *opaque, hwaddr addr, uint64_t val,
unsigned width)
{
PMSMBus *s = opaque;
uint8_t clear_byte_done;
SMBUS_DPRINTF("SMB writeb port=0x%04" HWADDR_PRIx
" val=0x%02" PRIx64 "\n", addr, val);
switch(addr) {
case SMBHSTSTS:
clear_byte_done = s->smb_stat & val & STS_BYTE_DONE;
s->smb_stat &= ~(val & ~STS_HOST_BUSY);
if (clear_byte_done && smb_byte_by_byte(s)) {
uint8_t read = s->smb_addr & 0x01;
if (s->in_i2c_block_read) {
/* See comment below PROT_I2C_BLOCK_READ above. */
read = 1;
}
s->smb_index++;
if (s->smb_index >= PM_SMBUS_MAX_MSG_SIZE) {
s->smb_index = 0;
}
if (!read && s->smb_index == s->smb_data0) {
uint8_t prot = (s->smb_ctl >> 2) & 0x07;
uint8_t cmd = s->smb_cmd;
uint8_t addr = s->smb_addr >> 1;
int ret;
if (prot == PROT_I2C_BLOCK_READ) {
s->smb_stat |= STS_DEV_ERR;
goto out;
}
ret = smbus_write_block(s->smbus, addr, cmd, s->smb_data,
s->smb_data0, !s->i2c_enable);
if (ret < 0) {
s->smb_stat |= STS_DEV_ERR;
goto out;
}
s->op_done = true;
s->smb_stat |= STS_INTR;
s->smb_stat &= ~STS_HOST_BUSY;
} else if (!read) {
s->smb_data[s->smb_index] = s->smb_blkdata;
s->smb_stat |= STS_BYTE_DONE;
} else if (s->smb_ctl & CTL_LAST_BYTE) {
s->op_done = true;
if (s->in_i2c_block_read) {
s->in_i2c_block_read = false;
s->smb_blkdata = i2c_recv(s->smbus);
i2c_nack(s->smbus);
i2c_end_transfer(s->smbus);
} else {
s->smb_blkdata = s->smb_data[s->smb_index];
}
s->smb_index = 0;
s->smb_stat |= STS_INTR;
s->smb_stat &= ~STS_HOST_BUSY;
} else {
if (s->in_i2c_block_read) {
s->smb_blkdata = i2c_recv(s->smbus);
} else {
s->smb_blkdata = s->smb_data[s->smb_index];
}
s->smb_stat |= STS_BYTE_DONE;
}
}
break;
case SMBHSTCNT:
s->smb_ctl = val & ~CTL_START; /* CTL_START always reads 0 */
if (val & CTL_START) {
if (!s->op_done) {
s->smb_index = 0;
s->op_done = true;
if (s->in_i2c_block_read) {
s->in_i2c_block_read = false;
i2c_end_transfer(s->smbus);
}
}
smb_transaction_start(s);
}
if (s->smb_ctl & CTL_KILL) {
s->op_done = true;
s->smb_index = 0;
s->smb_stat |= STS_FAILED;
s->smb_stat &= ~STS_HOST_BUSY;
}
break;
case SMBHSTCMD:
s->smb_cmd = val;
break;
case SMBHSTADD:
s->smb_addr = val;
break;
case SMBHSTDAT0:
s->smb_data0 = val;
break;
case SMBHSTDAT1:
s->smb_data1 = val;
break;
case SMBBLKDAT:
if (s->smb_index >= PM_SMBUS_MAX_MSG_SIZE) {
s->smb_index = 0;
}
if (s->smb_auxctl & AUX_BLK) {
s->smb_data[s->smb_index++] = val;
} else {
s->smb_blkdata = val;
}
break;
case SMBAUXCTL:
s->smb_auxctl = val & AUX_MASK;
break;
default:
break;
}
out:
if (s->set_irq) {
s->set_irq(s, smb_irq_value(s));
}
}
static uint64_t smb_ioport_readb(void *opaque, hwaddr addr, unsigned width)
{
PMSMBus *s = opaque;
uint32_t val;
switch(addr) {
case SMBHSTSTS:
val = s->smb_stat;
if (s->start_transaction_on_status_read) {
/* execute command now */
s->start_transaction_on_status_read = false;
s->smb_stat &= ~STS_HOST_BUSY;
smb_transaction(s);
}
break;
case SMBHSTCNT:
val = s->smb_ctl & CTL_RETURN_MASK;
break;
case SMBHSTCMD:
val = s->smb_cmd;
break;
case SMBHSTADD:
val = s->smb_addr;
break;
case SMBHSTDAT0:
val = s->smb_data0;
break;
case SMBHSTDAT1:
val = s->smb_data1;
break;
case SMBBLKDAT:
if (s->smb_auxctl & AUX_BLK && !s->in_i2c_block_read) {
if (s->smb_index >= PM_SMBUS_MAX_MSG_SIZE) {
s->smb_index = 0;
}
val = s->smb_data[s->smb_index++];
if (!s->op_done && s->smb_index == s->smb_data0) {
s->op_done = true;
s->smb_index = 0;
s->smb_stat &= ~STS_HOST_BUSY;
}
} else {
val = s->smb_blkdata;
}
break;
case SMBAUXCTL:
val = s->smb_auxctl;
break;
default:
val = 0;
break;
}
SMBUS_DPRINTF("SMB readb port=0x%04" HWADDR_PRIx " val=0x%02x\n",
addr, val);
if (s->set_irq) {
s->set_irq(s, smb_irq_value(s));
}
return val;
}
static void pm_smbus_reset(PMSMBus *s)
{
s->op_done = true;
s->smb_index = 0;
s->smb_stat = 0;
}
static const MemoryRegionOps pm_smbus_ops = {
.read = smb_ioport_readb,
.write = smb_ioport_writeb,
.valid.min_access_size = 1,
.valid.max_access_size = 1,
.endianness = DEVICE_LITTLE_ENDIAN,
};
bool pm_smbus_vmstate_needed(void)
{
MachineClass *mc = MACHINE_GET_CLASS(qdev_get_machine());
return !mc->smbus_no_migration_support;
}
const VMStateDescription pmsmb_vmstate = {
.name = "pmsmb",
.version_id = 1,
.minimum_version_id = 1,
.fields = (VMStateField[]) {
VMSTATE_UINT8(smb_stat, PMSMBus),
VMSTATE_UINT8(smb_ctl, PMSMBus),
VMSTATE_UINT8(smb_cmd, PMSMBus),
VMSTATE_UINT8(smb_addr, PMSMBus),
VMSTATE_UINT8(smb_data0, PMSMBus),
VMSTATE_UINT8(smb_data1, PMSMBus),
VMSTATE_UINT32(smb_index, PMSMBus),
VMSTATE_UINT8_ARRAY(smb_data, PMSMBus, PM_SMBUS_MAX_MSG_SIZE),
VMSTATE_UINT8(smb_auxctl, PMSMBus),
VMSTATE_UINT8(smb_blkdata, PMSMBus),
VMSTATE_BOOL(i2c_enable, PMSMBus),
VMSTATE_BOOL(op_done, PMSMBus),
VMSTATE_BOOL(in_i2c_block_read, PMSMBus),
VMSTATE_BOOL(start_transaction_on_status_read, PMSMBus),
VMSTATE_END_OF_LIST()
}
};
void pm_smbus_init(DeviceState *parent, PMSMBus *smb, bool force_aux_blk)
{
smb->op_done = true;
smb->reset = pm_smbus_reset;
smb->smbus = i2c_init_bus(parent, "i2c");
if (force_aux_blk) {
smb->smb_auxctl |= AUX_BLK;
}
memory_region_init_io(&smb->io, OBJECT(parent), &pm_smbus_ops, smb,
"pm-smbus", 64);
}
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