Re: [request for testing] isl, cyapa on chromebooks

On Mon, 10 Oct 2016 14:35:22 +0300
Andriy Gapon <avg_at_FreeBSD.org> wrote:

> On 09/10/2016 23:22, Warner Losh wrote:
> > There seems to be enough information present in the smbios data to
> > know what devices are at what addresses. Perhaps we should use it as
> > much as possible in well controlled situations to move this
> > knowledge into the OS.  
> 
> So, I was thinking about maybe doing something like this to preserve
> the status quo, to avoid requiring manual hints and to lay a
> foundation for the proper Chromebook I2C slave discovery:
> 
> 
> static struct {
> 	uint32_t	ctlrid,
> 	const char	*name;
> 	uint_t		addr;
> } slaves[] = {
> 	{ 0x9c628086,	"isl",		0x88 },
> 	{ 0x9c628086,	"cyapa",	0xce },
> }
> 
> static void
> chromebook_i2c_identify(driver_t *driver, device_t bus)
> {
> 	device_t controller;
> 	device_t child;
> 	int i;
> 
> 	/*
> 	 * A stop gap approach to preserve the status quo.
> 	 * A more intelligent approach is required to correctly
> 	 * identify a machine model and hadrdware available on it.
> 	 * For instance, DMI could be used.
> 	 * See
> http://lxr.free-electrons.com/source/drivers/platform/chrome/chromeos_laptop.c
> 	 */
> 	controller = device_get_parent(bus);
> 	if (strcmp(device_get_name(controller), "ig4iic") != 0)
> 		return;
> 
> 	for (i = 0; i < nitems(slaves); i++) {
> 		if (device_find_child(bus, slave->name, -1) != NULL)
> 			continue;
> 		if (slave->ctlrid != pci_get_devid(controller))
> 			continue;
> 		child = BUS_ADD_CHILD(bus, 0, slave->name, -1);
> 		if (child != NULL)
> 			iicbus_set_addr(child, slave->addr);
> 	}
> }
> 
> static device_method_t chromebook_i2c_methods[] = {
> 	DEVMETHOD(device_identify,	chromebook_i2c_identify),
> 	{ 0, 0 }
> };
> 
> static driver_t chromebook_i2c_driver = {
> 	"chromebook_i2c",
> 	chromebook_i2c_methods,
> 	0	/* no softc */
> };
> 
> static devclass_t chromebook_i2c_devclass;
> 
> DRIVER_MODULE(chromebook_i2c, iicbus, chromebook_i2c_driver,
>     chromebook_i2c_devclass, 0, 0);
> MODULE_DEPEND(chromebook_i2c, iicbus, IICBUS_MINVER, IICBUS_PREFVER,
>     IICBUS_MAXVER);
> MODULE_VERSION(chromebook_i2c, 1);
> 
> The idea is that this is a driver that listens for new iicbus-es and
> adds isl and cyapa devices to a bus if some criteria are met.
> 

For the Acer c720, these criteria would be:

smbios.bios.vendor=="coreboot"
smbios.system.maker=="Acer"
smbios.system.product=="Peppy"

See also

boot/i386/libi386/biosmem.c
dev/atkbdc/atkbdc.c

- Michael

-- 
Michael Gmelin