[RFC PATCH 02/11] kvm tools: virtio: move fdt node generation into core mmio code

[Will Deacon <will.deacon@arm.com>]

Generating fdt nodes for virtio-mmio devices should be in the core code,
not hidden inside the architecture code for ARM.

This patch reworks the .data field of struct device_header for
virtio-mmio devices, so that it contains a function pointer which can
be called to generate the FDT node for each device.

Signed-off-by: Will Deacon <will.deacon@arm.com>
---
 tools/kvm/arm/fdt.c     | 30 ++++++++++--------------------
 tools/kvm/virtio/mmio.c | 38 +++++++++++++++++++++++++++++++++++++-
 2 files changed, 47 insertions(+), 21 deletions(-)

diff --git a/tools/kvm/arm/fdt.c b/tools/kvm/arm/fdt.c
index c61bf58..7198fe8 100644
--- a/tools/kvm/arm/fdt.c
+++ b/tools/kvm/arm/fdt.c
@@ -69,28 +69,15 @@ static void generate_cpu_nodes(void *fdt, struct kvm *kvm)
 	_FDT(fdt_end_node(fdt));
 }
 
-#define DEVICE_NAME_MAX_LEN 32
-static void generate_virtio_mmio_node(void *fdt, struct virtio_mmio *vmmio)
+static void generate_irq_prop(void *fdt, u8 irq)
 {
-	char dev_name[DEVICE_NAME_MAX_LEN];
-	u64 addr = vmmio->addr;
-	u64 reg_prop[] = {
-		cpu_to_fdt64(addr),
-		cpu_to_fdt64(VIRTIO_MMIO_IO_SIZE)
-	};
 	u32 irq_prop[] = {
 		cpu_to_fdt32(GIC_FDT_IRQ_TYPE_SPI),
-		cpu_to_fdt32(vmmio->irq - GIC_SPI_IRQ_BASE),
+		cpu_to_fdt32(irq - GIC_SPI_IRQ_BASE),
 		cpu_to_fdt32(GIC_FDT_IRQ_FLAGS_EDGE_LO_HI),
 	};
 
-	snprintf(dev_name, DEVICE_NAME_MAX_LEN, "virtio@%llx", addr);
-
-	_FDT(fdt_begin_node(fdt, dev_name));
-	_FDT(fdt_property_string(fdt, "compatible", "virtio,mmio"));
-	_FDT(fdt_property(fdt, "reg", reg_prop, sizeof(reg_prop)));
 	_FDT(fdt_property(fdt, "interrupts", irq_prop, sizeof(irq_prop)));
-	_FDT(fdt_end_node(fdt));
 }
 
 static int setup_fdt(struct kvm *kvm)
@@ -105,8 +92,10 @@ static int setup_fdt(struct kvm *kvm)
 	void *fdt		= staging_fdt;
 	void *fdt_dest		= guest_flat_to_host(kvm,
 						     kvm->arch.dtb_guest_start);
-	void (*generate_fdt_nodes)(void *, struct kvm *, u32)
-				= kvm->cpus[0]->generate_fdt_nodes;
+	void (*generate_mmio_fdt_nodes)(void *, struct device_header *,
+					void (*)(void *, u8));
+	void (*generate_cpu_peripheral_fdt_nodes)(void *, struct kvm *, u32)
+					= kvm->cpus[0]->generate_fdt_nodes;
 
 	/* Create new tree without a reserve map */
 	_FDT(fdt_create(fdt, FDT_MAX_SIZE));
@@ -144,13 +133,14 @@ static int setup_fdt(struct kvm *kvm)
 
 	/* CPU and peripherals (interrupt controller, timers, etc) */
 	generate_cpu_nodes(fdt, kvm);
-	if (generate_fdt_nodes)
-		generate_fdt_nodes(fdt, kvm, gic_phandle);
+	if (generate_cpu_peripheral_fdt_nodes)
+		generate_cpu_peripheral_fdt_nodes(fdt, kvm, gic_phandle);
 
 	/* Virtio MMIO devices */
 	dev_hdr = device__first_dev(DEVICE_BUS_MMIO);
 	while (dev_hdr) {
-		generate_virtio_mmio_node(fdt, dev_hdr->data);
+		generate_mmio_fdt_nodes = dev_hdr->data;
+		generate_mmio_fdt_nodes(fdt, dev_hdr, generate_irq_prop);
 		dev_hdr = device__next_dev(dev_hdr);
 	}
 
diff --git a/tools/kvm/virtio/mmio.c b/tools/kvm/virtio/mmio.c
index bd30f37..a4e4855 100644
--- a/tools/kvm/virtio/mmio.c
+++ b/tools/kvm/virtio/mmio.c
@@ -5,6 +5,7 @@
 #include "kvm/virtio.h"
 #include "kvm/kvm.h"
 #include "kvm/irq.h"
+#include "kvm/fdt.h"
 
 #include <linux/virtio_mmio.h>
 #include <string.h>
@@ -215,6 +216,41 @@ static void virtio_mmio_mmio_callback(u64 addr, u8 *data, u32 len,
 		virtio_mmio_config_in(offset, data, len, ptr);
 }
 
+#ifdef CONFIG_HAS_LIBFDT
+#define DEVICE_NAME_MAX_LEN 32
+static void generate_virtio_mmio_fdt_node(void *fdt,
+					  struct device_header *dev_hdr,
+					  void (*generate_irq_prop)(void *fdt,
+								    u8 irq))
+{
+	char dev_name[DEVICE_NAME_MAX_LEN];
+	struct virtio_mmio *vmmio = container_of(dev_hdr,
+						 struct virtio_mmio,
+						 dev_hdr);
+	u64 addr = vmmio->addr;
+	u64 reg_prop[] = {
+		cpu_to_fdt64(addr),
+		cpu_to_fdt64(VIRTIO_MMIO_IO_SIZE),
+	};
+
+	snprintf(dev_name, DEVICE_NAME_MAX_LEN, "virtio@%llx", addr);
+
+	_FDT(fdt_begin_node(fdt, dev_name));
+	_FDT(fdt_property_string(fdt, "compatible", "virtio,mmio"));
+	_FDT(fdt_property(fdt, "reg", reg_prop, sizeof(reg_prop)));
+	generate_irq_prop(fdt, vmmio->irq);
+	_FDT(fdt_end_node(fdt));
+}
+#else
+static void generate_virtio_mmio_fdt_node(void *fdt,
+					  struct device_header *dev_hdr,
+					  void (*generate_irq_prop)(void *fdt,
+								    u8 irq))
+{
+	die("Unable to generate device tree nodes without libfdt\n");
+}
+#endif
+
 int virtio_mmio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
 		     int device_id, int subsys_id, int class)
 {
@@ -241,7 +277,7 @@ int virtio_mmio_init(struct kvm *kvm, void *dev, struct virtio_device *vdev,
 	vmmio->irq = line;
 	vmmio->dev_hdr = (struct device_header) {
 		.bus_type	= DEVICE_BUS_MMIO,
-		.data		= vmmio,
+		.data		= generate_virtio_mmio_fdt_node,
 	};
 
 	device__register(&vmmio->dev_hdr);
-- 
1.8.0