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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>
This commit is contained in:
BALATON Zoltan 2018-06-19 10:52:15 +02:00 committed by David Gibson
parent 39aeba6caa
commit ef9173a5c0
4 changed files with 19 additions and 1 deletions
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1
default-configs/ppc-softmmu.mak
View File

@ -26,6 +26,7 @@ CONFIG_USB_EHCI_SYSBUS=y
CONFIG_SM501=y
CONFIG_IDE_SII3112=y
CONFIG_I2C=y
CONFIG_BITBANG_I2C=y
# For Macs
CONFIG_MAC=y

1
default-configs/ppcemb-softmmu.mak
View File

@ -19,3 +19,4 @@ CONFIG_USB_EHCI_SYSBUS=y
CONFIG_SM501=y
CONFIG_IDE_SII3112=y
CONFIG_I2C=y
CONFIG_BITBANG_I2C=y

14
hw/i2c/ppc4xx_i2c.c
View File

@ -30,6 +30,7 @@
#include "cpu.h"
#include "hw/hw.h"
#include "hw/i2c/ppc4xx_i2c.h"
#include "bitbang_i2c.h"
#define PPC4xx_I2C_MEM_SIZE 18
@ -46,6 +47,11 @@
#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);
@ -289,7 +295,12 @@ static void ppc4xx_i2c_writeb(void *opaque, hwaddr addr, uint64_t value,
i2c->xtcntlss = value;
break;
case 16:
i2c->directcntl = value & 0x7;
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) {
@ -322,6 +333,7 @@ static void ppc4xx_i2c_init(Object *o)
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)

4
include/hw/i2c/ppc4xx_i2c.h
View File

@ -31,6 +31,9 @@
#include "hw/sysbus.h"
#include "hw/i2c/i2c.h"
/* from hw/i2c/bitbang_i2c.h */
typedef struct bitbang_i2c_interface bitbang_i2c_interface;
#define TYPE_PPC4xx_I2C "ppc4xx-i2c"
#define PPC4xx_I2C(obj) OBJECT_CHECK(PPC4xxI2CState, (obj), TYPE_PPC4xx_I2C)
@ -42,6 +45,7 @@ typedef struct PPC4xxI2CState {
I2CBus *bus;
qemu_irq irq;
MemoryRegion iomem;
bitbang_i2c_interface *bitbang;
uint8_t mdata;
uint8_t lmadr;
uint8_t hmadr;