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x86, olpc: Add missing elements to device tree
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In response to new device tree code in the kernel, OLPC will start
using it for probing of certain devices. However, some firmware fixes
are needed to put the devicetree into a usable state.

Retain compatibility with old firmware by fixing up the device tree
at boot-time if it does not contain the new nodes/properties that
we need for probing. This is the same approach taken on PPC platforms.

Signed-off-by: Daniel Drake <dsd@laptop.org>
Link: http://lkml.kernel.org/r/1309019658-1712-2-git-send-email-dsd@laptop.org
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Acked-by: Andres Salomon <dilinger@queued.net>
Cc: devicetree-discuss@lists.ozlabs.org
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
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Daniel Drake authored and H. Peter Anvin committed Jul 6, 2011
1 parent fe0d422 commit f70d8ef
Showing 1 changed file with 103 additions and 0 deletions.
103 changes: 103 additions & 0 deletions arch/x86/platform/olpc/olpc_dt.c
Original file line number Diff line number Diff line change
Expand Up @@ -165,13 +165,116 @@ static struct of_pdt_ops prom_olpc_ops __initdata = {
.pkg2path = olpc_dt_pkg2path,
};

static phandle __init olpc_dt_finddevice(const char *path)
{
phandle node;
const void *args[] = { path };
void *res[] = { &node };

if (olpc_ofw("finddevice", args, res)) {
pr_err("olpc_dt: finddevice failed!\n");
return 0;
}

if ((s32) node == -1)
return 0;

return node;
}

static int __init olpc_dt_interpret(const char *words)
{
int result;
const void *args[] = { words };
void *res[] = { &result };

if (olpc_ofw("interpret", args, res)) {
pr_err("olpc_dt: interpret failed!\n");
return -1;
}

return result;
}

/*
* Extract board revision directly from OFW device tree.
* We can't use olpc_platform_info because that hasn't been set up yet.
*/
static u32 __init olpc_dt_get_board_revision(void)
{
phandle node;
__be32 rev;
int r;

node = olpc_dt_finddevice("/");
if (!node)
return 0;

r = olpc_dt_getproperty(node, "board-revision-int",
(char *) &rev, sizeof(rev));
if (r < 0)
return 0;

return be32_to_cpu(rev);
}

void __init olpc_dt_fixup(void)
{
int r;
char buf[64];
phandle node;
u32 board_rev;

node = olpc_dt_finddevice("/battery@0");
if (!node)
return;

/*
* If the battery node has a compatible property, we are running a new
* enough firmware and don't have fixups to make.
*/
r = olpc_dt_getproperty(node, "compatible", buf, sizeof(buf));
if (r > 0)
return;

pr_info("PROM DT: Old firmware detected, applying fixes\n");

/* Add olpc,xo1-battery compatible marker to battery node */
olpc_dt_interpret("\" /battery@0\" find-device"
" \" olpc,xo1-battery\" +compatible"
" device-end");

board_rev = olpc_dt_get_board_revision();
if (!board_rev)
return;

if (board_rev >= olpc_board_pre(0xd0)) {
/* XO-1.5: add dcon device */
olpc_dt_interpret("\" /pci/display@1\" find-device"
" new-device"
" \" dcon\" device-name \" olpc,xo1-dcon\" +compatible"
" finish-device device-end");
} else {
/* XO-1: add dcon device, mark RTC as olpc,xo1-rtc */
olpc_dt_interpret("\" /pci/display@1,1\" find-device"
" new-device"
" \" dcon\" device-name \" olpc,xo1-dcon\" +compatible"
" finish-device device-end"
" \" /rtc\" find-device"
" \" olpc,xo1-rtc\" +compatible"
" device-end");
}
}

void __init olpc_dt_build_devicetree(void)
{
phandle root;

if (!olpc_ofw_is_installed())
return;

olpc_dt_fixup();

root = olpc_dt_getsibling(0);
if (!root) {
pr_err("PROM: unable to get root node from OFW!\n");
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