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smbus: allow child devices to be added via hints

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This will allow to add slave drivers in the same fashion as for iicbus.

Also, allow other code to add a child device and set its 'addr' ivar.
The ivar can only be set if it's unset, it can not be changed.
That could be used, for example, by a platform driver that has
a precise description of the hardware and, thus, knows what drivers
can handle what slaves.

The slave auto-probing code is unsafe and broken because it uses
7-bit slave addresses.  It's going to be removed.

Note: internally the driver uses address of zero as an unset address
while smbus_get_addr() returns it as -1 for compatibility reasons.
The address is expected to be unset only for children that do not
work with slaves like, for example, smb(4).

Reviewed by:	jhb
Differential Revision: https://reviews.freebsd.org/D8173
This commit is contained in:
Andriy Gapon 2016-10-12 06:58:01 +00:00
parent 0e3cfd98fc
commit 94dce59911
2 changed files with 139 additions and 63 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
sys/dev/smbus/smbconf.h
View File

@ -34,6 +34,10 @@
#define n(flags) (~(flags) & (flags))
/* Order constants for smbus children. */
#define SMBUS_ORDER_HINTED 20
#define SMBUS_ORDER_PNP 40
/*
* How tsleep() is called in smb_request_bus().
*/

198
sys/dev/smbus/smbus.c
View File

@ -31,6 +31,7 @@ __FBSDID("$FreeBSD$");
#include <sys/param.h>
#include <sys/systm.h>
#include <sys/lock.h>
#include <sys/malloc.h>
#include <sys/module.h>
#include <sys/mutex.h>
#include <sys/bus.h>
@ -41,54 +42,16 @@ __FBSDID("$FreeBSD$");
#include "smbus_if.h"
#include "bus_if.h"
struct smbus_ivar
{
uint8_t addr;
};
/*
* Autoconfiguration and support routines for System Management bus
*/
static void smbus_probe_device(device_t dev, u_char addr);
/*
* Device methods
*/
static int smbus_probe(device_t);
static int smbus_attach(device_t);
static int smbus_detach(device_t);
static int smbus_child_location_str(device_t parent, device_t child,
char *buf, size_t buflen);
static int smbus_print_child(device_t parent, device_t child);
static void smbus_probe_device(device_t dev, u_char* addr);
static int smbus_read_ivar(device_t parent, device_t child, int which,
uintptr_t *result);
static device_method_t smbus_methods[] = {
/* device interface */
DEVMETHOD(device_probe, smbus_probe),
DEVMETHOD(device_attach, smbus_attach),
DEVMETHOD(device_detach, smbus_detach),
/* bus interface */
DEVMETHOD(bus_add_child, bus_generic_add_child),
DEVMETHOD(bus_child_location_str, smbus_child_location_str),
DEVMETHOD(bus_driver_added, bus_generic_driver_added),
DEVMETHOD(bus_print_child, smbus_print_child),
DEVMETHOD(bus_read_ivar, smbus_read_ivar),
DEVMETHOD_END
};
driver_t smbus_driver = {
"smbus",
smbus_methods,
sizeof(struct smbus_softc),
};
devclass_t smbus_devclass;
/*
* At 'probe' time, we add all the devices which we know about to the
* bus. The generic attach routine will probe and attach them if they
* are alive.
*/
static int
smbus_probe(device_t dev)
{
@ -107,9 +70,9 @@ smbus_attach(device_t dev)
mtx_init(&sc->lock, device_get_nameunit(dev), "smbus", MTX_DEF);
bus_generic_probe(dev);
for (addr = SMBUS_ADDR_MIN; addr < SMBUS_ADDR_MAX; ++addr) {
sc->addrs[addr] = addr;
smbus_probe_device(dev, &sc->addrs[addr]);
smbus_probe_device(dev, addr);
}
bus_enumerate_hinted_children(dev);
bus_generic_attach(dev);
return (0);
@ -124,6 +87,7 @@ smbus_detach(device_t dev)
error = bus_generic_detach(dev);
if (error)
return (error);
device_delete_children(dev);
mtx_destroy(&sc->lock);
return (0);
@ -135,34 +99,78 @@ smbus_generic_intr(device_t dev, u_char devaddr, char low, char high, int err)
}
static void
smbus_probe_device(device_t dev, u_char* addr)
smbus_probe_device(device_t dev, u_char addr)
{
device_t child;
int error;
u_char cmd;
u_char buf[2];
struct smbus_ivar *devi;
cmd = 0x01;
error = smbus_trans(dev, *addr, cmd,
error = smbus_trans(dev, addr, cmd,
SMB_TRANS_NOCNT | SMB_TRANS_NOREPORT,
NULL, 0, buf, 1, NULL);
if (error == 0) {
if (bootverbose)
device_printf(dev, "Probed address 0x%02x\n", *addr);
child = device_add_child(dev, NULL, -1);
device_set_ivars(child, addr);
device_printf(dev, "Probed address 0x%02x\n", addr);
child = BUS_ADD_CHILD(dev, SMBUS_ORDER_PNP, NULL, -1);
if (child == NULL)
return;
devi = device_get_ivars(child);
devi->addr = addr;
}
}
static device_t
smbus_add_child(device_t dev, u_int order, const char *name, int unit)
{
struct smbus_ivar *devi;
device_t child;
child = device_add_child_ordered(dev, order, name, unit);
if (child == NULL)
return (child);
devi = malloc(sizeof(struct smbus_ivar), M_DEVBUF, M_NOWAIT | M_ZERO);
if (devi == NULL) {
device_delete_child(dev, child);
return (NULL);
}
device_set_ivars(child, devi);
return (child);
}
static void
smbus_hinted_child(device_t bus, const char *dname, int dunit)
{
struct smbus_ivar *devi;
device_t child;
int addr;
addr = 0;
resource_int_value(dname, dunit, "addr", &addr);
if (addr > UINT8_MAX) {
device_printf(bus, "ignored incorrect slave address hint 0x%x"
" for %s%d\n", addr, dname, dunit);
return;
}
child = BUS_ADD_CHILD(bus, SMBUS_ORDER_HINTED, dname, dunit);
if (child == NULL)
return;
devi = device_get_ivars(child);
devi->addr = addr;
}
static int
smbus_child_location_str(device_t parent, device_t child, char *buf,
size_t buflen)
{
unsigned char *addr;
struct smbus_ivar *devi;
addr = device_get_ivars(child);
if (addr)
snprintf(buf, buflen, "addr=0x%x", *addr);
devi = device_get_ivars(child);
if (devi->addr != 0)
snprintf(buf, buflen, "addr=0x%x", devi->addr);
else if (buflen)
buf[0] = 0;
return (0);
@ -171,28 +179,30 @@ smbus_child_location_str(device_t parent, device_t child, char *buf,
static int
smbus_print_child(device_t parent, device_t child)
{
unsigned char *addr;
struct smbus_ivar *devi;
int retval;
addr = device_get_ivars(child);
devi = device_get_ivars(child);
retval = bus_print_child_header(parent, child);
if (addr)
retval += printf(" at addr 0x%x", *addr);
if (devi->addr != 0)
retval += printf(" at addr 0x%x", devi->addr);
retval += bus_print_child_footer(parent, child);
return (retval);
}
static int
smbus_read_ivar(device_t parent, device_t child, int which,
uintptr_t *result)
smbus_read_ivar(device_t parent, device_t child, int which, uintptr_t *result)
{
unsigned char *addr;
struct smbus_ivar *devi;
addr = device_get_ivars(child);
devi = device_get_ivars(child);
switch (which) {
case SMBUS_IVAR_ADDR:
*result = (addr == NULL) ? -1 : *addr;
if (devi->addr != 0)
*result = devi->addr;
else
*result = -1;
break;
default:
return (ENOENT);
@ -200,4 +210,66 @@ smbus_read_ivar(device_t parent, device_t child, int which,
return (0);
}
static int
smbus_write_ivar(device_t parent, device_t child, int which, uintptr_t value)
{
struct smbus_ivar *devi;
devi = device_get_ivars(child);
switch (which) {
case SMBUS_IVAR_ADDR:
/* Allow to set but no change the slave address. */
if (devi->addr != 0)
return (EINVAL);
devi->addr = value;
break;
default:
return (ENOENT);
}
return (0);
}
static void
smbus_probe_nomatch(device_t bus, device_t child)
{
struct smbus_ivar *devi = device_get_ivars(child);
/*
* Ignore (self-identified) devices without a slave address set.
* For example, smb(4).
*/
if (devi->addr != 0)
device_printf(bus, "<unknown device> at addr %#x\n",
devi->addr);
}
/*
* Device methods
*/
static device_method_t smbus_methods[] = {
/* device interface */
DEVMETHOD(device_probe, smbus_probe),
DEVMETHOD(device_attach, smbus_attach),
DEVMETHOD(device_detach, smbus_detach),
/* bus interface */
DEVMETHOD(bus_add_child, smbus_add_child),
DEVMETHOD(bus_hinted_child, smbus_hinted_child),
DEVMETHOD(bus_probe_nomatch, smbus_probe_nomatch),
DEVMETHOD(bus_child_location_str, smbus_child_location_str),
DEVMETHOD(bus_print_child, smbus_print_child),
DEVMETHOD(bus_read_ivar, smbus_read_ivar),
DEVMETHOD(bus_write_ivar, smbus_write_ivar),
DEVMETHOD_END
};
driver_t smbus_driver = {
"smbus",
smbus_methods,
sizeof(struct smbus_softc),
};
devclass_t smbus_devclass;
MODULE_VERSION(smbus, SMBUS_MODVER);