ARM: integrator: fix OF-related regression

Commit 07e461cd7e73a84f0e3757932b93cc80976fd749
"of: Ensure unique names without sacrificing determinism"
caused a boot failure regression on the Integrator machines.

The problem is probably caused by fiddling too much with
the device tree population in the OF init function, such
as passing the SoC bus device as parent when populating
the device tree.

This patch fixes the problem by:

- Avoiding to explicitly look up the tree root
- Look up devices needed before device population from
  the match only, passing NULL as root
- Passing NULL as root and parent when calling
  of_platform_populate()

After this the Integrators boot again. Tested on
Integrator/AP and Integrator/CP.

Cc: Grant Likely <grant.likely@linaro.org>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

arch/arm/mach-integrator/integrator_ap.c

@@ -480,25 +480,18 @@ static const struct of_device_id ebi_match[] = {
 static void __init ap_init_of(void)
 {
 	unsigned long sc_dec;
-	struct device_node *root;
 	struct device_node *syscon;
 	struct device_node *ebi;
 	struct device *parent;
 	struct soc_device *soc_dev;
 	struct soc_device_attribute *soc_dev_attr;
 	u32 ap_sc_id;
-	int err;
 	int i;
 
-	/* Here we create an SoC device for the root node */
-	root = of_find_node_by_path("/");
-	if (!root)
-		return;
-
-	syscon = of_find_matching_node(root, ap_syscon_match);
+	syscon = of_find_matching_node(NULL, ap_syscon_match);
 	if (!syscon)
 		return;
-	ebi = of_find_matching_node(root, ebi_match);
+	ebi = of_find_matching_node(NULL, ebi_match);
 	if (!ebi)
 		return;
 
@@ -509,19 +502,17 @@ static void __init ap_init_of(void)
 	if (!ebi_base)
 		return;
 
+	of_platform_populate(NULL, of_default_bus_match_table,
+			ap_auxdata_lookup, NULL);
+
 	ap_sc_id = readl(ap_syscon_base);
 
 	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
 	if (!soc_dev_attr)
 		return;
 
-	err = of_property_read_string(root, "compatible",
-				      &soc_dev_attr->soc_id);
-	if (err)
-		return;
-	err = of_property_read_string(root, "model", &soc_dev_attr->machine);
-	if (err)
-		return;
+	soc_dev_attr->soc_id = "XVC";
+	soc_dev_attr->machine = "Integrator/AP";
 	soc_dev_attr->family = "Integrator";
 	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%c",
 					   'A' + (ap_sc_id & 0x0f));
@@ -536,9 +527,6 @@ static void __init ap_init_of(void)
 	parent = soc_device_to_device(soc_dev);
 	integrator_init_sysfs(parent, ap_sc_id);
 
-	of_platform_populate(root, of_default_bus_match_table,
-			ap_auxdata_lookup, parent);
-
 	sc_dec = readl(ap_syscon_base + INTEGRATOR_SC_DEC_OFFSET);
 	for (i = 0; i < 4; i++) {
 		struct lm_device *lmdev;

arch/arm/mach-integrator/integrator_cp.c

@@ -279,20 +279,13 @@ static const struct of_device_id intcp_syscon_match[] = {
 
 static void __init intcp_init_of(void)
 {
-	struct device_node *root;
 	struct device_node *cpcon;
 	struct device *parent;
 	struct soc_device *soc_dev;
 	struct soc_device_attribute *soc_dev_attr;
 	u32 intcp_sc_id;
-	int err;
 
-	/* Here we create an SoC device for the root node */
-	root = of_find_node_by_path("/");
-	if (!root)
-		return;
-
-	cpcon = of_find_matching_node(root, intcp_syscon_match);
+	cpcon = of_find_matching_node(NULL, intcp_syscon_match);
 	if (!cpcon)
 		return;
 
@@ -300,19 +293,17 @@ static void __init intcp_init_of(void)
 	if (!intcp_con_base)
 		return;
 
+	of_platform_populate(NULL, of_default_bus_match_table,
+			     intcp_auxdata_lookup, NULL);
+
 	intcp_sc_id = readl(intcp_con_base);
 
 	soc_dev_attr = kzalloc(sizeof(*soc_dev_attr), GFP_KERNEL);
 	if (!soc_dev_attr)
 		return;
 
-	err = of_property_read_string(root, "compatible",
-				      &soc_dev_attr->soc_id);
-	if (err)
-		return;
-	err = of_property_read_string(root, "model", &soc_dev_attr->machine);
-	if (err)
-		return;
+	soc_dev_attr->soc_id = "XCV";
+	soc_dev_attr->machine = "Integrator/CP";
 	soc_dev_attr->family = "Integrator";
 	soc_dev_attr->revision = kasprintf(GFP_KERNEL, "%c",
 					   'A' + (intcp_sc_id & 0x0f));
@@ -326,8 +317,6 @@ static void __init intcp_init_of(void)
 
 	parent = soc_device_to_device(soc_dev);
 	integrator_init_sysfs(parent, intcp_sc_id);
-	of_platform_populate(root, of_default_bus_match_table,
-			intcp_auxdata_lookup, parent);
 }
 
 static const char * intcp_dt_board_compat[] = {