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qemu/hw/i2c/ppc4xx_i2c.c
BALATON Zoltan ef9173a5c0 ppc4xx_i2c: Implement directcntl register 
As well as being able to generate its own i2c transactions, the ppc4xx
i2c controller has a DIRECTCNTL register which allows explicit control
of the i2c lines.

Using this register an OS can directly bitbang i2c operations. In
order to let emulated i2c devices respond to this, we need to wire up
the DIRECTCNTL register to qemu's bitbanged i2c handling code.

Signed-off-by: BALATON Zoltan <balaton@eik.bme.hu>
Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
2018-06-21 21:22:53 +10:00

360 lines
11 KiB
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/*
* PPC4xx I2C controller emulation
*
* Copyright (c) 2007 Jocelyn Mayer
* Copyright (c) 2012 François Revol
* Copyright (c) 2016-2018 BALATON Zoltan
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "qemu/osdep.h"
#include "qemu-common.h"
#include "qemu/log.h"
#include "cpu.h"
#include "hw/hw.h"
#include "hw/i2c/ppc4xx_i2c.h"
#include "bitbang_i2c.h"
#define PPC4xx_I2C_MEM_SIZE 18
#define IIC_CNTL_PT (1 << 0)
#define IIC_CNTL_READ (1 << 1)
#define IIC_CNTL_CHT (1 << 2)
#define IIC_CNTL_RPST (1 << 3)
#define IIC_STS_PT (1 << 0)
#define IIC_STS_ERR (1 << 2)
#define IIC_STS_MDBS (1 << 5)
#define IIC_EXTSTS_XFRA (1 << 0)
#define IIC_XTCNTLSS_SRST (1 << 0)
#define IIC_DIRECTCNTL_SDAC (1 << 3)
#define IIC_DIRECTCNTL_SCLC (1 << 2)
#define IIC_DIRECTCNTL_MSDA (1 << 1)
#define IIC_DIRECTCNTL_MSCL (1 << 0)
static void ppc4xx_i2c_reset(DeviceState *s)
{
PPC4xxI2CState *i2c = PPC4xx_I2C(s);
/* FIXME: Should also reset bus?
*if (s->address != ADDR_RESET) {
* i2c_end_transfer(s->bus);
*}
*/
i2c->mdata = 0;
i2c->lmadr = 0;
i2c->hmadr = 0;
i2c->cntl = 0;
i2c->mdcntl = 0;
i2c->sts = 0;
i2c->extsts = 0x8f;
i2c->lsadr = 0;
i2c->hsadr = 0;
i2c->clkdiv = 0;
i2c->intrmsk = 0;
i2c->xfrcnt = 0;
i2c->xtcntlss = 0;
i2c->directcntl = 0xf;
}
static inline bool ppc4xx_i2c_is_master(PPC4xxI2CState *i2c)
{
return true;
}
static uint64_t ppc4xx_i2c_readb(void *opaque, hwaddr addr, unsigned int size)
{
PPC4xxI2CState *i2c = PPC4xx_I2C(opaque);
uint64_t ret;
switch (addr) {
case 0:
ret = i2c->mdata;
if (ppc4xx_i2c_is_master(i2c)) {
ret = 0xff;
if (!(i2c->sts & IIC_STS_MDBS)) {
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: Trying to read "
"without starting transfer\n",
TYPE_PPC4xx_I2C, __func__);
} else {
int pending = (i2c->cntl >> 4) & 3;
/* get the next byte */
int byte = i2c_recv(i2c->bus);
if (byte < 0) {
qemu_log_mask(LOG_GUEST_ERROR, "[%s]%s: read failed "
"for device 0x%02x\n", TYPE_PPC4xx_I2C,
__func__, i2c->lmadr);
ret = 0xff;
} else {
ret = byte;
/* Raise interrupt if enabled */
/*ppc4xx_i2c_raise_interrupt(i2c)*/;
}
if (!pending) {
i2c->sts &= ~IIC_STS_MDBS;
/*i2c_end_transfer(i2c->bus);*/
/*} else if (i2c->cntl & (IIC_CNTL_RPST | IIC_CNTL_CHT)) {*/
} else if (pending) {
/* current smbus implementation doesn't like
multibyte xfer repeated start */
i2c_end_transfer(i2c->bus);
if (i2c_start_transfer(i2c->bus, i2c->lmadr >> 1, 1)) {
/* if non zero is returned, the adress is not valid */
i2c->sts &= ~IIC_STS_PT;
i2c->sts |= IIC_STS_ERR;
i2c->extsts |= IIC_EXTSTS_XFRA;
} else {
/*i2c->sts |= IIC_STS_PT;*/
i2c->sts |= IIC_STS_MDBS;
i2c->sts &= ~IIC_STS_ERR;
i2c->extsts = 0;
}
}
pending--;
i2c->cntl = (i2c->cntl & 0xcf) | (pending << 4);
}
} else {
qemu_log_mask(LOG_UNIMP, "[%s]%s: slave mode not implemented\n",
TYPE_PPC4xx_I2C, __func__);
}
break;
case 4:
ret = i2c->lmadr;
break;
case 5:
ret = i2c->hmadr;
break;
case 6:
ret = i2c->cntl;
break;
case 7:
ret = i2c->mdcntl;
break;
case 8:
ret = i2c->sts;
break;
case 9:
ret = i2c->extsts;
break;
case 10:
ret = i2c->lsadr;
break;
case 11:
ret = i2c->hsadr;
break;
case 12:
ret = i2c->clkdiv;
break;
case 13:
ret = i2c->intrmsk;
break;
case 14:
ret = i2c->xfrcnt;
break;
case 15:
ret = i2c->xtcntlss;
break;
case 16:
ret = i2c->directcntl;
break;
default:
if (addr < PPC4xx_I2C_MEM_SIZE) {
qemu_log_mask(LOG_UNIMP, "%s: Unimplemented register 0x%"
HWADDR_PRIx "\n", __func__, addr);
} else {
qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad address 0x%"
HWADDR_PRIx "\n", __func__, addr);
}
ret = 0;
break;
}
return ret;
}
static void ppc4xx_i2c_writeb(void *opaque, hwaddr addr, uint64_t value,
unsigned int size)
{
PPC4xxI2CState *i2c = opaque;
switch (addr) {
case 0:
i2c->mdata = value;
if (!i2c_bus_busy(i2c->bus)) {
/* assume we start a write transfer */
if (i2c_start_transfer(i2c->bus, i2c->lmadr >> 1, 0)) {
/* if non zero is returned, the adress is not valid */
i2c->sts &= ~IIC_STS_PT;
i2c->sts |= IIC_STS_ERR;
i2c->extsts |= IIC_EXTSTS_XFRA;
} else {
i2c->sts |= IIC_STS_PT;
i2c->sts &= ~IIC_STS_ERR;
i2c->extsts = 0;
}
}
if (i2c_bus_busy(i2c->bus)) {
if (i2c_send(i2c->bus, i2c->mdata)) {
/* if the target return non zero then end the transfer */
i2c->sts &= ~IIC_STS_PT;
i2c->sts |= IIC_STS_ERR;
i2c->extsts |= IIC_EXTSTS_XFRA;
i2c_end_transfer(i2c->bus);
}
}
break;
case 4:
i2c->lmadr = value;
if (i2c_bus_busy(i2c->bus)) {
i2c_end_transfer(i2c->bus);
}
break;
case 5:
i2c->hmadr = value;
break;
case 6:
i2c->cntl = value;
if (i2c->cntl & IIC_CNTL_PT) {
if (i2c->cntl & IIC_CNTL_READ) {
if (i2c_bus_busy(i2c->bus)) {
/* end previous transfer */
i2c->sts &= ~IIC_STS_PT;
i2c_end_transfer(i2c->bus);
}
if (i2c_start_transfer(i2c->bus, i2c->lmadr >> 1, 1)) {
/* if non zero is returned, the adress is not valid */
i2c->sts &= ~IIC_STS_PT;
i2c->sts |= IIC_STS_ERR;
i2c->extsts |= IIC_EXTSTS_XFRA;
} else {
/*i2c->sts |= IIC_STS_PT;*/
i2c->sts |= IIC_STS_MDBS;
i2c->sts &= ~IIC_STS_ERR;
i2c->extsts = 0;
}
} else {
/* we actually already did the write transfer... */
i2c->sts &= ~IIC_STS_PT;
}
}
break;
case 7:
i2c->mdcntl = value & 0xdf;
break;
case 8:
i2c->sts &= ~(value & 0xa);
break;
case 9:
i2c->extsts &= ~(value & 0x8f);
break;
case 10:
i2c->lsadr = value;
break;
case 11:
i2c->hsadr = value;
break;
case 12:
i2c->clkdiv = value;
break;
case 13:
i2c->intrmsk = value;
break;
case 14:
i2c->xfrcnt = value & 0x77;
break;
case 15:
if (value & IIC_XTCNTLSS_SRST) {
/* Is it actually a full reset? U-Boot sets some regs before */
ppc4xx_i2c_reset(DEVICE(i2c));
break;
}
i2c->xtcntlss = value;
break;
case 16:
i2c->directcntl = value & (IIC_DIRECTCNTL_SDAC & IIC_DIRECTCNTL_SCLC);
i2c->directcntl |= (value & IIC_DIRECTCNTL_SCLC ? 1 : 0);
bitbang_i2c_set(i2c->bitbang, BITBANG_I2C_SCL,
i2c->directcntl & IIC_DIRECTCNTL_MSCL);
i2c->directcntl |= bitbang_i2c_set(i2c->bitbang, BITBANG_I2C_SDA,
(value & IIC_DIRECTCNTL_SDAC) != 0) << 1;
break;
default:
if (addr < PPC4xx_I2C_MEM_SIZE) {
qemu_log_mask(LOG_UNIMP, "%s: Unimplemented register 0x%"
HWADDR_PRIx "\n", __func__, addr);
} else {
qemu_log_mask(LOG_GUEST_ERROR, "%s: Bad address 0x%"
HWADDR_PRIx "\n", __func__, addr);
}
break;
}
}
static const MemoryRegionOps ppc4xx_i2c_ops = {
.read = ppc4xx_i2c_readb,
.write = ppc4xx_i2c_writeb,
.valid.min_access_size = 1,
.valid.max_access_size = 4,
.impl.min_access_size = 1,
.impl.max_access_size = 1,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static void ppc4xx_i2c_init(Object *o)
{
PPC4xxI2CState *s = PPC4xx_I2C(o);
memory_region_init_io(&s->iomem, OBJECT(s), &ppc4xx_i2c_ops, s,
TYPE_PPC4xx_I2C, PPC4xx_I2C_MEM_SIZE);
sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
sysbus_init_irq(SYS_BUS_DEVICE(s), &s->irq);
s->bus = i2c_init_bus(DEVICE(s), "i2c");
s->bitbang = bitbang_i2c_init(s->bus);
}
static void ppc4xx_i2c_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->reset = ppc4xx_i2c_reset;
}
static const TypeInfo ppc4xx_i2c_type_info = {
.name = TYPE_PPC4xx_I2C,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(PPC4xxI2CState),
.instance_init = ppc4xx_i2c_init,
.class_init = ppc4xx_i2c_class_init,
};
static void ppc4xx_i2c_register_types(void)
{
type_register_static(&ppc4xx_i2c_type_info);
}
type_init(ppc4xx_i2c_register_types)
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