diff mbox

[RFC,1/3] checks: Add infrastructure for setting bus type of nodes

Message ID 1458780021-5052-1-git-send-email-robh@kernel.org
State New
Headers show

Commit Message

Rob Herring March 24, 2016, 12:40 a.m. UTC 
In preparation to support bus specific checks, add the necessary
infrastructure to determine the bus type for nodes. Initially, PCI and
simple bus are supported.

Signed-off-by: Rob Herring <robh@kernel.org>

---
David,

Hopefully this matches what you had in mind for bus checks.

Rob

 checks.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 dtc.h    | 11 +++++++++
 2 files changed, 90 insertions(+)

-- 
2.5.0

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Comments

Rob Herring March 31, 2016, 3:17 p.m. UTC | #1 
On Thu, Mar 31, 2016 at 12:22 AM, David Gibson
<david@gibson.dropbear.id.au> wrote:
> On Wed, Mar 23, 2016 at 07:40:19PM -0500, Rob Herring wrote:

>> In preparation to support bus specific checks, add the necessary

>> infrastructure to determine the bus type for nodes. Initially, PCI and

>> simple bus are supported.

>>

>> Signed-off-by: Rob Herring <robh@kernel.org>

>> ---

>> David,

>

> Sorry it's taken me a while to look at this.  I've been a mixture of

> busy and sick :/


No problem.

[...]

>> +static bool is_pci_bridge(struct node *node)

>> +{

>> +     struct property *prop;

>> +

>> +     if (!node)

>> +             return false;

>> +

>> +     prop = get_property(node, "device_type");

>> +     if (!prop)

>> +             return false;

>> +

>> +     if (strcmp(prop->val.val, "pci") == 0)

>> +             return true;

>> +

>> +     return false;

>> +}

>

> So, I don't love using device_type here, since that's generally

> discouraged in modern flat trees, but I don't know of a better way to

> detect a pci bridge, so I guess it's ok.


True, but pci, cpu, and memory remain as accepted uses. We'd have to
define a "pci-bridge" or "pci-bus" compatible to replace it.

>> +struct bus_type pci_bus_type = {

>> +        .expected_addr_cells = 3,

>> +        .expected_size_cells = 2,

>

> I'm a bit torn here.  Part of me wants to suggest a 'check_bridge'

> function which handles this and can also make more subtle checks, but

> then just the expected cells values will handle nearly all real cases

> more succinctly.


I left them as you had them, but I'm not so sure these are all that
useful. It works for PCI as the sizes are fixed, but then we could
just check against fixed values. For simple-bus, we need more
flexibility because the size could be 1 or 2. For other cases like I2C
or SPI buses, we know the sizes, but we can't really detect those
buses.

Rob
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diff mbox

Patch

diff --git a/checks.c b/checks.c
index 386f956..48e926e 100644
--- a/checks.c
+++ b/checks.c
@@ -527,6 +527,84 @@  static void fixup_path_references(struct check *c, struct node *dt,
 ERROR(path_references, NULL, NULL, fixup_path_references, NULL,
       &duplicate_node_names);
 
+static bool is_pci_bridge(struct node *node)
+{
+	struct property *prop;
+
+	if (!node)
+		return false;
+
+	prop = get_property(node, "device_type");
+	if (!prop)
+		return false;
+
+	if (strcmp(prop->val.val, "pci") == 0)
+		return true;
+
+	return false;
+}
+
+struct bus_type pci_bus_type = {
+        .expected_addr_cells = 3,
+        .expected_size_cells = 2,
+        .is_type = is_pci_bridge,
+};
+
+static bool is_simple_bridge(struct node *node)
+{
+	struct property *prop;
+	int len = 0;
+
+	if (!node)
+		return false;
+
+	/* root node is special case defaulting to simple-bus */
+	if (!node->parent)
+		return true;
+
+	prop = get_property(node, "compatible");
+	if (!prop)
+		return false;
+
+	do {
+		const char *str = prop->val.val;
+
+		if (strcmp(str, "simple-bus") == 0)
+			return true;
+		len += strlen(str) + 1;
+		str += len;
+	} while (len < prop->val.len);
+
+	return false;
+}
+
+struct bus_type simple_bus_type = {
+	.expected_addr_cells = -1, /* For don't care */
+	.expected_size_cells = -1,
+	.is_type = is_simple_bridge,
+};
+
+struct bus_type *bus_types[] = {
+	&pci_bus_type,
+	&simple_bus_type,
+	NULL
+};
+
+static void fixup_bus_type(struct check *c, struct node *dt,
+				  struct node *node)
+{
+	struct bus_type **bus;
+
+	for (bus = bus_types; *bus != NULL; bus++) {
+		if (!(*bus)->is_type(node))
+			continue;
+
+		node->bus_type = *bus;
+		break;
+	}
+}
+ERROR(bus_type, NULL, fixup_bus_type, NULL, NULL);
+
 /*
  * Semantic checks
  */
@@ -685,6 +763,7 @@  static struct check *check_table[] = {
 
 	&explicit_phandles,
 	&phandle_references, &path_references,
+	&bus_type,
 
 	&address_cells_is_cell, &size_cells_is_cell, &interrupt_cells_is_cell,
 	&device_type_is_string, &model_is_string, &status_is_string,
diff --git a/dtc.h b/dtc.h
index 56212c8..c1a1fe9 100644
--- a/dtc.h
+++ b/dtc.h
@@ -132,6 +132,16 @@  struct label {
 	struct label *next;
 };
 
+struct check;
+struct node;
+
+struct bus_type {
+        int expected_addr_cells;
+        int expected_size_cells;
+        bool (*is_type)(struct node *node);
+        void (*check_unit_addr)(struct check *c, struct node *dt, struct node *node);
+};
+
 struct property {
 	bool deleted;
 	char *name;
@@ -158,6 +168,7 @@  struct node {
 	int addr_cells, size_cells;
 
 	struct label *labels;
+	struct bus_type *bus_type;
 };
 
 #define for_each_label_withdel(l0, l) \