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Merge remote-tracking branch 'remotes/cminyard/tags/for-qemu-6.1-v1' into staging

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Add a bus multiplexer device

This patch set adds a bus multiplexer and the necessary infrastructure
in the I2C code to allow it to work.

These are common on systems with lots of I2C devices, like an IPMI BMC.

# gpg: Signature made Thu 13 May 2021 22:48:07 BST
# gpg:                using RSA key FD0D5CE67CE0F59A6688268661F38C90919BFF81
# gpg: Good signature from "Corey Minyard <cminyard@mvista.com>" [unknown]
# gpg:                 aka "Corey Minyard <minyard@acm.org>" [unknown]
# gpg:                 aka "Corey Minyard <corey@minyard.net>" [unknown]
# gpg:                 aka "Corey Minyard <minyard@mvista.com>" [unknown]
# gpg: WARNING: This key is not certified with a trusted signature!
# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: FD0D 5CE6 7CE0 F59A 6688  2686 61F3 8C90 919B FF81

* remotes/cminyard/tags/for-qemu-6.1-v1:
  hw/i2c: add pca954x i2c-mux switch
  hw/i2c: move search to i2c_scan_bus method
  hw/i2c: add match method for device search
  hw/i2c: name I2CNode list in I2CBus

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
This commit is contained in:
Peter Maydell
2021-05-14 14:26:23 +01:00
parent 96662996ed 065177eece
commit 499063d00a
8 changed files with 383 additions and 14 deletions
Download Patch File Download Diff File Expand all files Collapse all files

6
MAINTAINERS
View File

@@ -2024,6 +2024,12 @@ S: Maintained
F: hw/net/tulip.c
F: hw/net/tulip.h
pca954x
M: Patrick Venture <venture@google.com>
S: Maintained
F: hw/i2c/i2c_mux_pca954x.c
F: include/hw/i2c/i2c_mux_pca954x.h
Generic Loader
M: Alistair Francis <alistair@alistair23.me>
S: Maintained

4
hw/i2c/Kconfig
View File

@@ -28,3 +28,7 @@ config IMX_I2C
config MPC_I2C
bool
select I2C
config PCA954X
bool
select I2C

55
hw/i2c/core.c
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@@ -77,6 +77,30 @@ int i2c_bus_busy(I2CBus *bus)
return !QLIST_EMPTY(&bus->current_devs);
}
bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
I2CNodeList *current_devs)
{
BusChild *kid;
QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
DeviceState *qdev = kid->child;
I2CSlave *candidate = I2C_SLAVE(qdev);
I2CSlaveClass *sc = I2C_SLAVE_GET_CLASS(candidate);
if (sc->match_and_add(candidate, address, broadcast, current_devs)) {
if (!broadcast) {
return true;
}
}
}
/*
* If broadcast was true, and the list was full or empty, return true. If
* broadcast was false, return false.
*/
return broadcast;
}
/* TODO: Make this handle multiple masters. */
/*
* Start or continue an i2c transaction. When this is called for the
@@ -93,7 +117,6 @@ int i2c_bus_busy(I2CBus *bus)
*/
int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
{
BusChild *kid;
I2CSlaveClass *sc;
I2CNode *node;
bool bus_scanned = false;
@@ -115,18 +138,8 @@ int i2c_start_transfer(I2CBus *bus, uint8_t address, int recv)
* terminating the previous transaction.
*/
if (QLIST_EMPTY(&bus->current_devs)) {
QTAILQ_FOREACH(kid, &bus->qbus.children, sibling) {
DeviceState *qdev = kid->child;
I2CSlave *candidate = I2C_SLAVE(qdev);
if ((candidate->address == address) || (bus->broadcast)) {
node = g_malloc(sizeof(struct I2CNode));
node->elt = candidate;
QLIST_INSERT_HEAD(&bus->current_devs, node, next);
if (!bus->broadcast) {
break;
}
}
}
/* Disregard whether devices were found. */
(void)i2c_scan_bus(bus, address, bus->broadcast, &bus->current_devs);
bus_scanned = true;
}
@@ -290,12 +303,28 @@ I2CSlave *i2c_slave_create_simple(I2CBus *bus, const char *name, uint8_t addr)
return dev;
}
static bool i2c_slave_match(I2CSlave *candidate, uint8_t address,
bool broadcast, I2CNodeList *current_devs)
{
if ((candidate->address == address) || (broadcast)) {
I2CNode *node = g_malloc(sizeof(struct I2CNode));
node->elt = candidate;
QLIST_INSERT_HEAD(current_devs, node, next);
return true;
}
/* Not found and not broadcast. */
return false;
}
static void i2c_slave_class_init(ObjectClass *klass, void *data)
{
DeviceClass *k = DEVICE_CLASS(klass);
I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
set_bit(DEVICE_CATEGORY_MISC, k->categories);
k->bus_type = TYPE_I2C_BUS;
device_class_set_props(k, i2c_props);
sc->match_and_add = i2c_slave_match;
}
static const TypeInfo i2c_slave_type_info = {

290
hw/i2c/i2c_mux_pca954x.c Normal file
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@@ -0,0 +1,290 @@
/*
* I2C multiplexer for PCA954x series of I2C multiplexer/switch chips.
*
* Copyright 2021 Google LLC
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License as published by the
* Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program 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 General Public License
* for more details.
*/
#include "qemu/osdep.h"
#include "qapi/error.h"
#include "hw/i2c/i2c.h"
#include "hw/i2c/i2c_mux_pca954x.h"
#include "hw/i2c/smbus_slave.h"
#include "hw/qdev-core.h"
#include "hw/sysbus.h"
#include "qemu/log.h"
#include "qemu/module.h"
#include "qemu/queue.h"
#include "qom/object.h"
#include "trace.h"
#define PCA9548_CHANNEL_COUNT 8
#define PCA9546_CHANNEL_COUNT 4
/*
* struct Pca954xChannel - The i2c mux device will have N of these states
* that own the i2c channel bus.
* @bus: The owned channel bus.
* @enabled: Is this channel active?
*/
typedef struct Pca954xChannel {
SysBusDevice parent;
I2CBus *bus;
bool enabled;
} Pca954xChannel;
#define TYPE_PCA954X_CHANNEL "pca954x-channel"
#define PCA954X_CHANNEL(obj) \
OBJECT_CHECK(Pca954xChannel, (obj), TYPE_PCA954X_CHANNEL)
/*
* struct Pca954xState - The pca954x state object.
* @control: The value written to the mux control.
* @channel: The set of i2c channel buses that act as channels which own the
* i2c children.
*/
typedef struct Pca954xState {
SMBusDevice parent;
uint8_t control;
/* The channel i2c buses. */
Pca954xChannel channel[PCA9548_CHANNEL_COUNT];
} Pca954xState;
/*
* struct Pca954xClass - The pca954x class object.
* @nchans: The number of i2c channels this device has.
*/
typedef struct Pca954xClass {
SMBusDeviceClass parent;
uint8_t nchans;
} Pca954xClass;
#define TYPE_PCA954X "pca954x"
OBJECT_DECLARE_TYPE(Pca954xState, Pca954xClass, PCA954X)
/*
* For each channel, if it's enabled, recursively call match on those children.
*/
static bool pca954x_match(I2CSlave *candidate, uint8_t address,
bool broadcast,
I2CNodeList *current_devs)
{
Pca954xState *mux = PCA954X(candidate);
Pca954xClass *mc = PCA954X_GET_CLASS(mux);
int i;
/* They are talking to the mux itself (or all devices enabled). */
if ((candidate->address == address) || broadcast) {
I2CNode *node = g_malloc(sizeof(struct I2CNode));
node->elt = candidate;
QLIST_INSERT_HEAD(current_devs, node, next);
if (!broadcast) {
return true;
}
}
for (i = 0; i < mc->nchans; i++) {
if (!mux->channel[i].enabled) {
continue;
}
if (i2c_scan_bus(mux->channel[i].bus, address, broadcast,
current_devs)) {
if (!broadcast) {
return true;
}
}
}
/* If we arrived here we didn't find a match, return broadcast. */
return broadcast;
}
static void pca954x_enable_channel(Pca954xState *s, uint8_t enable_mask)
{
Pca954xClass *mc = PCA954X_GET_CLASS(s);
int i;
/*
* For each channel, check if their bit is set in enable_mask and if yes,
* enable it, otherwise disable, hide it.
*/
for (i = 0; i < mc->nchans; i++) {
if (enable_mask & (1 << i)) {
s->channel[i].enabled = true;
} else {
s->channel[i].enabled = false;
}
}
}
static void pca954x_write(Pca954xState *s, uint8_t data)
{
s->control = data;
pca954x_enable_channel(s, data);
trace_pca954x_write_bytes(data);
}
static int pca954x_write_data(SMBusDevice *d, uint8_t *buf, uint8_t len)
{
Pca954xState *s = PCA954X(d);
if (len == 0) {
qemu_log_mask(LOG_GUEST_ERROR, "%s: writing empty data\n", __func__);
return -1;
}
/*
* len should be 1, because they write one byte to enable/disable channels.
*/
if (len > 1) {
qemu_log_mask(LOG_GUEST_ERROR,
"%s: extra data after channel selection mask\n",
__func__);
return -1;
}
pca954x_write(s, buf[0]);
return 0;
}
static uint8_t pca954x_read_byte(SMBusDevice *d)
{
Pca954xState *s = PCA954X(d);
uint8_t data = s->control;
trace_pca954x_read_data(data);
return data;
}
static void pca954x_enter_reset(Object *obj, ResetType type)
{
Pca954xState *s = PCA954X(obj);
/* Reset will disable all channels. */
pca954x_write(s, 0);
}
I2CBus *pca954x_i2c_get_bus(I2CSlave *mux, uint8_t channel)
{
Pca954xClass *pc = PCA954X_GET_CLASS(mux);
Pca954xState *pca954x = PCA954X(mux);
g_assert(channel < pc->nchans);
return I2C_BUS(qdev_get_child_bus(DEVICE(&pca954x->channel[channel]),
"i2c-bus"));
}
static void pca954x_channel_init(Object *obj)
{
Pca954xChannel *s = PCA954X_CHANNEL(obj);
s->bus = i2c_init_bus(DEVICE(s), "i2c-bus");
/* Start all channels as disabled. */
s->enabled = false;
}
static void pca954x_channel_class_init(ObjectClass *klass, void *data)
{
DeviceClass *dc = DEVICE_CLASS(klass);
dc->desc = "Pca954x Channel";
}
static void pca9546_class_init(ObjectClass *klass, void *data)
{
Pca954xClass *s = PCA954X_CLASS(klass);
s->nchans = PCA9546_CHANNEL_COUNT;
}
static void pca9548_class_init(ObjectClass *klass, void *data)
{
Pca954xClass *s = PCA954X_CLASS(klass);
s->nchans = PCA9548_CHANNEL_COUNT;
}
static void pca954x_realize(DeviceState *dev, Error **errp)
{
Pca954xState *s = PCA954X(dev);
Pca954xClass *c = PCA954X_GET_CLASS(s);
int i;
/* SMBus modules. Cannot fail. */
for (i = 0; i < c->nchans; i++) {
sysbus_realize(SYS_BUS_DEVICE(&s->channel[i]), &error_abort);
}
}
static void pca954x_init(Object *obj)
{
Pca954xState *s = PCA954X(obj);
Pca954xClass *c = PCA954X_GET_CLASS(obj);
int i;
/* Only initialize the children we expect. */
for (i = 0; i < c->nchans; i++) {
object_initialize_child(obj, "channel[*]", &s->channel[i],
TYPE_PCA954X_CHANNEL);
}
}
static void pca954x_class_init(ObjectClass *klass, void *data)
{
I2CSlaveClass *sc = I2C_SLAVE_CLASS(klass);
ResettableClass *rc = RESETTABLE_CLASS(klass);
DeviceClass *dc = DEVICE_CLASS(klass);
SMBusDeviceClass *k = SMBUS_DEVICE_CLASS(klass);
sc->match_and_add = pca954x_match;
rc->phases.enter = pca954x_enter_reset;
dc->desc = "Pca954x i2c-mux";
dc->realize = pca954x_realize;
k->write_data = pca954x_write_data;
k->receive_byte = pca954x_read_byte;
}
static const TypeInfo pca954x_info[] = {
{
.name = TYPE_PCA954X,
.parent = TYPE_SMBUS_DEVICE,
.instance_size = sizeof(Pca954xState),
.instance_init = pca954x_init,
.class_size = sizeof(Pca954xClass),
.class_init = pca954x_class_init,
.abstract = true,
},
{
.name = TYPE_PCA9546,
.parent = TYPE_PCA954X,
.class_init = pca9546_class_init,
},
{
.name = TYPE_PCA9548,
.parent = TYPE_PCA954X,
.class_init = pca9548_class_init,
},
{
.name = TYPE_PCA954X_CHANNEL,
.parent = TYPE_SYS_BUS_DEVICE,
.class_init = pca954x_channel_class_init,
.instance_size = sizeof(Pca954xChannel),
.instance_init = pca954x_channel_init,
}
};
DEFINE_TYPES(pca954x_info)

1
hw/i2c/meson.build
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@@ -14,4 +14,5 @@ i2c_ss.add(when: 'CONFIG_SMBUS_EEPROM', if_true: files('smbus_eeprom.c'))
i2c_ss.add(when: 'CONFIG_VERSATILE_I2C', if_true: files('versatile_i2c.c'))
i2c_ss.add(when: 'CONFIG_OMAP', if_true: files('omap_i2c.c'))
i2c_ss.add(when: 'CONFIG_PPC4XX', if_true: files('ppc4xx_i2c.c'))
i2c_ss.add(when: 'CONFIG_PCA954X', if_true: files('i2c_mux_pca954x.c'))
softmmu_ss.add_all(when: 'CONFIG_I2C', if_true: i2c_ss)

5
hw/i2c/trace-events
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@@ -26,3 +26,8 @@ npcm7xx_smbus_recv_byte(const char *id, uint8_t value) "%s recv byte: 0x%02x"
npcm7xx_smbus_stop(const char *id) "%s stopping"
npcm7xx_smbus_nack(const char *id) "%s nacking"
npcm7xx_smbus_recv_fifo(const char *id, uint8_t received, uint8_t expected) "%s recv fifo: received %u, expected %u"
# i2c-mux-pca954x.c
pca954x_write_bytes(uint8_t value) "PCA954X write data: 0x%02x"
pca954x_read_data(uint8_t value) "PCA954X read data: 0x%02x"

17
include/hw/i2c/i2c.h
View File

@@ -16,6 +16,7 @@ enum i2c_event {
I2C_NACK /* Masker NACKed a receive byte. */
};
typedef struct I2CNodeList I2CNodeList;
#define TYPE_I2C_SLAVE "i2c-slave"
OBJECT_DECLARE_TYPE(I2CSlave, I2CSlaveClass,
@@ -39,6 +40,16 @@ struct I2CSlaveClass {
* return code is not used and should be zero.
*/
int (*event)(I2CSlave *s, enum i2c_event event);
/*
* Check if this device matches the address provided. Returns bool of
* true if it matches (or broadcast), and updates the device list, false
* otherwise.
*
* If broadcast is true, match should add the device and return true.
*/
bool (*match_and_add)(I2CSlave *candidate, uint8_t address, bool broadcast,
I2CNodeList *current_devs);
};
struct I2CSlave {
@@ -58,9 +69,11 @@ struct I2CNode {
QLIST_ENTRY(I2CNode) next;
};
typedef QLIST_HEAD(I2CNodeList, I2CNode) I2CNodeList;
struct I2CBus {
BusState qbus;
QLIST_HEAD(, I2CNode) current_devs;
I2CNodeList current_devs;
uint8_t saved_address;
bool broadcast;
};
@@ -74,6 +87,8 @@ void i2c_nack(I2CBus *bus);
int i2c_send_recv(I2CBus *bus, uint8_t *data, bool send);
int i2c_send(I2CBus *bus, uint8_t data);
uint8_t i2c_recv(I2CBus *bus);
bool i2c_scan_bus(I2CBus *bus, uint8_t address, bool broadcast,
I2CNodeList *current_devs);
/**
* Create an I2C slave device on the heap.

19
include/hw/i2c/i2c_mux_pca954x.h Normal file
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@@ -0,0 +1,19 @@
#ifndef QEMU_I2C_MUX_PCA954X
#define QEMU_I2C_MUX_PCA954X
#include "hw/i2c/i2c.h"
#define TYPE_PCA9546 "pca9546"
#define TYPE_PCA9548 "pca9548"
/**
* Retrieves the i2c bus associated with the specified channel on this i2c
* mux.
* @mux: an i2c mux device.
* @channel: the i2c channel requested
*
* Returns: a pointer to the associated i2c bus.
*/
I2CBus *pca954x_i2c_get_bus(I2CSlave *mux, uint8_t channel);
#endif