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qemu-e2k/hw/gpio/pl061.c
Peter Maydell ad06d56fc7 hw/gpio/pl061: Honour Luminary PL061 PUR and PDR registers 
The Luminary variant of the PL061 has registers GPIOPUR and GPIOPDR
which lets the guest configure whether the GPIO lines are pull-up,
pull-down, or truly floating. Instead of assuming all lines are pulled
high, honour the PUR and PDR registers.

For the plain PL061, continue to assume that lines have an external
pull-up resistor, as we did before.

The stellaris board actually relies on this behaviour -- the CD line
of the ssd0323 display device is connected to GPIO output C7, and it
is only because of a different bug which we're about to fix that we
weren't incorrectly driving this line high on reset and putting the
ssd0323 into data mode.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
2021-07-09 16:09:12 +01:00

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/*
* Arm PrimeCell PL061 General Purpose IO with additional
* Luminary Micro Stellaris bits.
*
* Copyright (c) 2007 CodeSourcery.
* Written by Paul Brook
*
* This code is licensed under the GPL.
*
* QEMU interface:
* + sysbus MMIO region 0: the device registers
* + sysbus IRQ: the GPIOINTR interrupt line
* + unnamed GPIO inputs 0..7: inputs to connect to the emulated GPIO lines
* + unnamed GPIO outputs 0..7: the emulated GPIO lines, considered as
* outputs
*/
#include "qemu/osdep.h"
#include "hw/irq.h"
#include "hw/sysbus.h"
#include "migration/vmstate.h"
#include "qemu/log.h"
#include "qemu/module.h"
#include "qom/object.h"
#include "trace.h"
static const uint8_t pl061_id[12] =
{ 0x00, 0x00, 0x00, 0x00, 0x61, 0x10, 0x04, 0x00, 0x0d, 0xf0, 0x05, 0xb1 };
static const uint8_t pl061_id_luminary[12] =
{ 0x00, 0x00, 0x00, 0x00, 0x61, 0x00, 0x18, 0x01, 0x0d, 0xf0, 0x05, 0xb1 };
#define TYPE_PL061 "pl061"
OBJECT_DECLARE_SIMPLE_TYPE(PL061State, PL061)
#define N_GPIOS 8
struct PL061State {
SysBusDevice parent_obj;
MemoryRegion iomem;
uint32_t locked;
uint32_t data;
uint32_t old_out_data;
uint32_t old_in_data;
uint32_t dir;
uint32_t isense;
uint32_t ibe;
uint32_t iev;
uint32_t im;
uint32_t istate;
uint32_t afsel;
uint32_t dr2r;
uint32_t dr4r;
uint32_t dr8r;
uint32_t odr;
uint32_t pur;
uint32_t pdr;
uint32_t slr;
uint32_t den;
uint32_t cr;
uint32_t amsel;
qemu_irq irq;
qemu_irq out[N_GPIOS];
const unsigned char *id;
};
static const VMStateDescription vmstate_pl061 = {
.name = "pl061",
.version_id = 4,
.minimum_version_id = 4,
.fields = (VMStateField[]) {
VMSTATE_UINT32(locked, PL061State),
VMSTATE_UINT32(data, PL061State),
VMSTATE_UINT32(old_out_data, PL061State),
VMSTATE_UINT32(old_in_data, PL061State),
VMSTATE_UINT32(dir, PL061State),
VMSTATE_UINT32(isense, PL061State),
VMSTATE_UINT32(ibe, PL061State),
VMSTATE_UINT32(iev, PL061State),
VMSTATE_UINT32(im, PL061State),
VMSTATE_UINT32(istate, PL061State),
VMSTATE_UINT32(afsel, PL061State),
VMSTATE_UINT32(dr2r, PL061State),
VMSTATE_UINT32(dr4r, PL061State),
VMSTATE_UINT32(dr8r, PL061State),
VMSTATE_UINT32(odr, PL061State),
VMSTATE_UINT32(pur, PL061State),
VMSTATE_UINT32(pdr, PL061State),
VMSTATE_UINT32(slr, PL061State),
VMSTATE_UINT32(den, PL061State),
VMSTATE_UINT32(cr, PL061State),
VMSTATE_UINT32_V(amsel, PL061State, 2),
VMSTATE_END_OF_LIST()
}
};
static uint8_t pl061_floating(PL061State *s)
{
/*
* Return mask of bits which correspond to pins configured as inputs
* and which are floating (neither pulled up to 1 nor down to 0).
*/
uint8_t floating;
if (s->id == pl061_id_luminary) {
/*
* If both PUR and PDR bits are clear, there is neither a pullup
* nor a pulldown in place, and the output truly floats.
*/
floating = ~(s->pur | s->pdr);
} else {
/* Assume outputs are pulled high. FIXME: this is board dependent. */
floating = 0;
}
return floating & ~s->dir;
}
static uint8_t pl061_pullups(PL061State *s)
{
/*
* Return mask of bits which correspond to pins configured as inputs
* and which are pulled up to 1.
*/
uint8_t pullups;
if (s->id == pl061_id_luminary) {
/*
* The Luminary variant of the PL061 has an extra registers which
* the guest can use to configure whether lines should be pullup
* or pulldown.
*/
pullups = s->pur;
} else {
/* Assume outputs are pulled high. FIXME: this is board dependent. */
pullups = 0xff;
}
return pullups & ~s->dir;
}
static void pl061_update(PL061State *s)
{
uint8_t changed;
uint8_t mask;
uint8_t out;
int i;
uint8_t pullups = pl061_pullups(s);
uint8_t floating = pl061_floating(s);
trace_pl061_update(DEVICE(s)->canonical_path, s->dir, s->data,
pullups, floating);
/*
* Pins configured as output are driven from the data register;
* otherwise if they're pulled up they're 1, and if they're floating
* then we give them the same value they had previously, so we don't
* report any change to the other end.
*/
out = (s->data & s->dir) | pullups | (s->old_out_data & floating);
changed = s->old_out_data ^ out;
if (changed) {
s->old_out_data = out;
for (i = 0; i < N_GPIOS; i++) {
mask = 1 << i;
if (changed & mask) {
int level = (out & mask) != 0;
trace_pl061_set_output(DEVICE(s)->canonical_path, i, level);
qemu_set_irq(s->out[i], level);
}
}
}
/* Inputs */
changed = (s->old_in_data ^ s->data) & ~s->dir;
if (changed) {
s->old_in_data = s->data;
for (i = 0; i < N_GPIOS; i++) {
mask = 1 << i;
if (changed & mask) {
trace_pl061_input_change(DEVICE(s)->canonical_path, i,
(s->data & mask) != 0);
if (!(s->isense & mask)) {
/* Edge interrupt */
if (s->ibe & mask) {
/* Any edge triggers the interrupt */
s->istate |= mask;
} else {
/* Edge is selected by IEV */
s->istate |= ~(s->data ^ s->iev) & mask;
}
}
}
}
}
/* Level interrupt */
s->istate |= ~(s->data ^ s->iev) & s->isense;
trace_pl061_update_istate(DEVICE(s)->canonical_path,
s->istate, s->im, (s->istate & s->im) != 0);
qemu_set_irq(s->irq, (s->istate & s->im) != 0);
}
static uint64_t pl061_read(void *opaque, hwaddr offset,
unsigned size)
{
PL061State *s = (PL061State *)opaque;
uint64_t r = 0;
switch (offset) {
case 0x0 ... 0x3ff: /* Data */
r = s->data & (offset >> 2);
break;
case 0x400: /* Direction */
r = s->dir;
break;
case 0x404: /* Interrupt sense */
r = s->isense;
break;
case 0x408: /* Interrupt both edges */
r = s->ibe;
break;
case 0x40c: /* Interrupt event */
r = s->iev;
break;
case 0x410: /* Interrupt mask */
r = s->im;
break;
case 0x414: /* Raw interrupt status */
r = s->istate;
break;
case 0x418: /* Masked interrupt status */
r = s->istate & s->im;
break;
case 0x420: /* Alternate function select */
r = s->afsel;
break;
case 0x500: /* 2mA drive */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->dr2r;
break;
case 0x504: /* 4mA drive */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->dr4r;
break;
case 0x508: /* 8mA drive */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->dr8r;
break;
case 0x50c: /* Open drain */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->odr;
break;
case 0x510: /* Pull-up */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->pur;
break;
case 0x514: /* Pull-down */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->pdr;
break;
case 0x518: /* Slew rate control */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->slr;
break;
case 0x51c: /* Digital enable */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->den;
break;
case 0x520: /* Lock */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->locked;
break;
case 0x524: /* Commit */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->cr;
break;
case 0x528: /* Analog mode select */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
r = s->amsel;
break;
case 0xfd0 ... 0xfff: /* ID registers */
r = s->id[(offset - 0xfd0) >> 2];
break;
default:
bad_offset:
qemu_log_mask(LOG_GUEST_ERROR,
"pl061_read: Bad offset %x\n", (int)offset);
break;
}
trace_pl061_read(DEVICE(s)->canonical_path, offset, r);
return r;
}
static void pl061_write(void *opaque, hwaddr offset,
uint64_t value, unsigned size)
{
PL061State *s = (PL061State *)opaque;
uint8_t mask;
trace_pl061_write(DEVICE(s)->canonical_path, offset, value);
switch (offset) {
case 0 ... 0x3ff:
mask = (offset >> 2) & s->dir;
s->data = (s->data & ~mask) | (value & mask);
pl061_update(s);
return;
case 0x400: /* Direction */
s->dir = value & 0xff;
break;
case 0x404: /* Interrupt sense */
s->isense = value & 0xff;
break;
case 0x408: /* Interrupt both edges */
s->ibe = value & 0xff;
break;
case 0x40c: /* Interrupt event */
s->iev = value & 0xff;
break;
case 0x410: /* Interrupt mask */
s->im = value & 0xff;
break;
case 0x41c: /* Interrupt clear */
s->istate &= ~value;
break;
case 0x420: /* Alternate function select */
mask = s->cr;
s->afsel = (s->afsel & ~mask) | (value & mask);
break;
case 0x500: /* 2mA drive */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->dr2r = value & 0xff;
break;
case 0x504: /* 4mA drive */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->dr4r = value & 0xff;
break;
case 0x508: /* 8mA drive */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->dr8r = value & 0xff;
break;
case 0x50c: /* Open drain */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->odr = value & 0xff;
break;
case 0x510: /* Pull-up */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->pur = value & 0xff;
break;
case 0x514: /* Pull-down */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->pdr = value & 0xff;
break;
case 0x518: /* Slew rate control */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->slr = value & 0xff;
break;
case 0x51c: /* Digital enable */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->den = value & 0xff;
break;
case 0x520: /* Lock */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->locked = (value != 0xacce551);
break;
case 0x524: /* Commit */
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
if (!s->locked)
s->cr = value & 0xff;
break;
case 0x528:
if (s->id != pl061_id_luminary) {
goto bad_offset;
}
s->amsel = value & 0xff;
break;
default:
bad_offset:
qemu_log_mask(LOG_GUEST_ERROR,
"pl061_write: Bad offset %x\n", (int)offset);
return;
}
pl061_update(s);
return;
}
static void pl061_reset(DeviceState *dev)
{
PL061State *s = PL061(dev);
/* reset values from PL061 TRM, Stellaris LM3S5P31 & LM3S8962 Data Sheet */
s->data = 0;
s->old_out_data = 0;
s->old_in_data = 0;
s->dir = 0;
s->isense = 0;
s->ibe = 0;
s->iev = 0;
s->im = 0;
s->istate = 0;
s->afsel = 0;
s->dr2r = 0xff;
s->dr4r = 0;
s->dr8r = 0;
s->odr = 0;
s->pur = 0;
s->pdr = 0;
s->slr = 0;
s->den = 0;
s->locked = 1;
s->cr = 0xff;
s->amsel = 0;
}
static void pl061_set_irq(void * opaque, int irq, int level)
{
PL061State *s = (PL061State *)opaque;
uint8_t mask;
mask = 1 << irq;
if ((s->dir & mask) == 0) {
s->data &= ~mask;
if (level)
s->data |= mask;
pl061_update(s);
}
}
static const MemoryRegionOps pl061_ops = {
.read = pl061_read,
.write = pl061_write,
.endianness = DEVICE_NATIVE_ENDIAN,
};
static void pl061_luminary_init(Object *obj)
{
PL061State *s = PL061(obj);
s->id = pl061_id_luminary;
}
static void pl061_init(Object *obj)
{
PL061State *s = PL061(obj);
DeviceState *dev = DEVICE(obj);
SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
s->id = pl061_id;
memory_region_init_io(&s->iomem, obj, &pl061_ops, s, "pl061", 0x1000);
sysbus_init_mmio(sbd, &s->iomem);
sysbus_init_irq(sbd, &s->irq);
qdev_init_gpio_in(dev, pl061_set_irq, N_GPIOS);
qdev_init_gpio_out(dev, s->out, N_GPIOS);
}
static void pl061_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->vmsd = &vmstate_pl061;
dc->reset = &pl061_reset;
}
static const TypeInfo pl061_info = {
.name = TYPE_PL061,
.parent = TYPE_SYS_BUS_DEVICE,
.instance_size = sizeof(PL061State),
.instance_init = pl061_init,
.class_init = pl061_class_init,
};
static const TypeInfo pl061_luminary_info = {
.name = "pl061_luminary",
.parent = TYPE_PL061,
.instance_init = pl061_luminary_init,
};
static void pl061_register_types(void)
{
type_register_static(&pl061_info);
type_register_static(&pl061_luminary_info);
}
type_init(pl061_register_types)
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