[dpdk-dev] [PATCH 03/14] eal/common: introduce union rte_device and related

[Jan Viktorin <viktorin@rehivetech.com>]

The union rte_device can be used in situations where we want to work with all
devices without distinguishing among bus-specific features (PCI, ...).
The target device type can be detected by reading the magic.

Also, the macros RTE_DEVICE_DECL and RTE_DEVICE_PTR_DECL are introduced to
provide a generic way to declare a device or a pointer to a device. The macros
aim to preserve API backwards-compatibility. Eg.

struct old_super_struct {             =>   struct old_super_struct {
    struct rte_pci_device *pci_dev;   =>        RTE_DEVICE_PTR_DECL(pci_dev);
    ...                               =>       ...
};                                    =>   };

struct old_super_struct inst;

The new code should reference inst.dev.pci, the old code can still use the
inst.pci_dev. The previously introduced magic is included so one can ask the
instance about its type:

if (inst.dev.magic == RTE_PCI_DEVICE_MAGIC) {
    ...
}

I don't like to include the rte_pci.h header here, however, I didn't find
a better way at the moment.

Signed-off-by: Jan Viktorin <viktorin@rehivetech.com>
---
 lib/librte_eal/common/include/rte_dev.h | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/lib/librte_eal/common/include/rte_dev.h b/lib/librte_eal/common/include/rte_dev.h
index f1b5507..c99d038 100644
--- a/lib/librte_eal/common/include/rte_dev.h
+++ b/lib/librte_eal/common/include/rte_dev.h
@@ -49,6 +49,7 @@ extern "C" {
 #include <stdio.h>
 #include <sys/queue.h>
 
+#include <rte_pci.h>
 #include <rte_log.h>
 
 __attribute__((format(printf, 2, 0)))
@@ -134,6 +135,32 @@ struct rte_driver {
 };
 
 /**
+ * Generic representation of a device.
+ */
+union rte_device {
+	unsigned int magic;
+	struct rte_pci_device pci;
+};
+
+/**
+ * The macro preserves API backwards compatibility.
+ */
+#define RTE_DEVICE_DECL(_pci)               \
+	union {                             \
+		union rte_device dev;       \
+		struct rte_pci_device _pci; \
+	}
+
+/**
+ * The macro preserves API backwards compatibility.
+ */
+#define RTE_DEVICE_PTR_DECL(_pci)            \
+	union {                              \
+		union rte_device *dev;       \
+		struct rte_pci_device *_pci; \
+	}
+
+/**
  * Register a device driver.
  *
  * @param driver
-- 
2.6.3