ARM: mvebu: add Armada 375 support to the coherency code

The Armada 375, like the Armada 370 and Armada XP, has a coherency
unit. However, unlike the coherency unit of 370/XP which does both CPU
and I/O coherency, the one on Armada 735 only does I/O
coherency. Therefore, instead of having two sets of registers (the
first one being used mainly to register each CPU in the coherency
fabric, the second one being used for the I/O coherency barrier), it
has only one set of register (for the I/O coherency barrier).

This commit adds a new "marvell,armada-375-coherency-fabric"
compatible string for this variant of the coherency fabric. The custom
DMA operations, and the way of triggering an I/O barrier is the same
as Armada 370/XP, so the code changes are minimal. However, the
set_cpu_coherent() function is not needed on Armada 375 and will not
work.

Signed-off-by: Thomas Petazzoni <[e-mail]>
Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Jason Cooper <[e-mail]>

Documentation/devicetree/bindings/arm/coherency-fabric.txt

···
 Coherency fabric
 ----------------
-Available on Marvell SOCs: Armada 370 and Armada XP
+Available on Marvell SOCs: Armada 370, Armada 375 and Armada XP
 
 Required properties:
 
···
  * "marvell,coherency-fabric", to be used for the coherency fabric of
    the Armada 370 and Armada XP.
 
-- reg: Should contain coherency fabric registers location and
-  length. First pair for the coherency fabric registers, second pair
-  for the per-CPU fabric registers registers.
+ * "marvell,armada-375-coherency-fabric", for the Armada 375 coherency
+   fabric.
 
-Example:
+- reg: Should contain coherency fabric registers location and
+  length.
+
+ * For "marvell,coherency-fabric", the first pair for the coherency
+   fabric registers, second pair for the per-CPU fabric registers.
+
+ * For "marvell,armada-375-coherency-fabric", only one pair is needed
+   for the per-CPU fabric registers.
+
+
+Examples:
 
 coherency-fabric@d0020200 {
 	compatible = "marvell,coherency-fabric";
 	reg = <0xd0020200 0xb0>,
 		<0xd0021810 0x1c>;
 
+};
+
+coherency-fabric@21810 {
+	compatible = "marvell,armada-375-coherency-fabric";
+	reg = <0x21810 0x1c>;
 };
 

arch/arm/mach-mvebu/coherency.c

···
 enum {
 	COHERENCY_FABRIC_TYPE_NONE,
 	COHERENCY_FABRIC_TYPE_ARMADA_370_XP,
+	COHERENCY_FABRIC_TYPE_ARMADA_375,
 };
 
 static struct of_device_id of_coherency_table[] = {
 	{.compatible = "marvell,coherency-fabric",
 	 .data = (void *) COHERENCY_FABRIC_TYPE_ARMADA_370_XP },
+	{.compatible = "marvell,armada-375-coherency-fabric",
+	 .data = (void *) COHERENCY_FABRIC_TYPE_ARMADA_375 },
 	{ /* end of list */ },
 };
 
···
 	set_cpu_coherent(cpu_logical_map(smp_processor_id()), 0);
 }
 
+static void __init armada_375_coherency_init(struct device_node *np)
+{
+	coherency_cpu_base = of_iomap(np, 0);
+}
+
 static int coherency_type(void)
 {
 	struct device_node *np;
···
 
 		/* Armada 370/XP coherency works in both UP and SMP */
 		if (type == COHERENCY_FABRIC_TYPE_ARMADA_370_XP)
+			return type;
+
+		/* Armada 375 coherency works only on SMP */
+		else if (type == COHERENCY_FABRIC_TYPE_ARMADA_375 && is_smp())
 			return type;
 
 		of_node_put(np);
···
 
 	if (type == COHERENCY_FABRIC_TYPE_ARMADA_370_XP)
 		armada_370_coherency_init(np);
+	else if (type == COHERENCY_FABRIC_TYPE_ARMADA_375)
+		armada_375_coherency_init(np);
 
 	return 0;
 }