[dpdk-dev] [PATCH v5 06/12] bus: get iommu class

[Santosh Shukla <santosh.shukla@caviumnetworks.com>]

API(rte_bus_get_iommu_class) helps to automatically detect and select
appropriate iova mapping scheme for iommu capable device on that bus.

Algorithm for iova scheme selection for bus:
0. Iterate through bus_list.
1. Collect each bus iova mode value and update into 'mode' var.
2. Mode selection scheme is:
if mode == 0 then iova mode is _pa,
if mode == 1 then iova mode is _pa,
if mode == 2 then iova mode is _va,
if mode == 3 then iova mode ia _pa.

So mode !=2  will be default iova mode (_pa).

Signed-off-by: Santosh Shukla <santosh.shukla@caviumnetworks.com>
Signed-off-by: Jerin Jacob <jerin.jacob@caviumnetworks.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Hemant Agrawal <hemant.agrawal@nxp.com>
---
v4 --> v5:
 - Reworded bus API description (Suggested by Hemant).

v3 --> v4:
 - Initialized mode to RTE_IOVA_DC in rte_bus_get_iommu_class.

 lib/librte_eal/bsdapp/eal/rte_eal_version.map   |  1 +
 lib/librte_eal/common/eal_common_bus.c          | 23 +++++++++++++++++++++++
 lib/librte_eal/common/eal_common_pci.c          |  1 +
 lib/librte_eal/common/include/rte_bus.h         | 25 +++++++++++++++++++++++++
 lib/librte_eal/linuxapp/eal/rte_eal_version.map |  1 +
 5 files changed, 51 insertions(+)

diff --git a/lib/librte_eal/bsdapp/eal/rte_eal_version.map b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
index 8d5bc5000..a30085a32 100644
--- a/lib/librte_eal/bsdapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/bsdapp/eal/rte_eal_version.map
@@ -242,5 +242,6 @@ DPDK_17.11 {
 
 	rte_pci_match;
 	rte_pci_get_iommu_class;
+	rte_bus_get_iommu_class;
 
 } DPDK_17.08;
diff --git a/lib/librte_eal/common/eal_common_bus.c b/lib/librte_eal/common/eal_common_bus.c
index 08bec2d93..a30a8982e 100644
--- a/lib/librte_eal/common/eal_common_bus.c
+++ b/lib/librte_eal/common/eal_common_bus.c
@@ -222,3 +222,26 @@ rte_bus_find_by_device_name(const char *str)
 		c[0] = '\0';
 	return rte_bus_find(NULL, bus_can_parse, name);
 }
+
+
+/*
+ * Get iommu class of devices on the bus.
+ */
+enum rte_iova_mode
+rte_bus_get_iommu_class(void)
+{
+	int mode = RTE_IOVA_DC;
+	struct rte_bus *bus;
+
+	TAILQ_FOREACH(bus, &rte_bus_list, next) {
+
+		if (bus->get_iommu_class)
+			mode |= bus->get_iommu_class();
+	}
+
+	if (mode != RTE_IOVA_VA) {
+		/* Use default IOVA mode */
+		mode = RTE_IOVA_PA;
+	}
+	return mode;
+}
diff --git a/lib/librte_eal/common/eal_common_pci.c b/lib/librte_eal/common/eal_common_pci.c
index 3b7d0a0ee..0f0e4b93b 100644
--- a/lib/librte_eal/common/eal_common_pci.c
+++ b/lib/librte_eal/common/eal_common_pci.c
@@ -564,6 +564,7 @@ struct rte_pci_bus rte_pci_bus = {
 		.plug = pci_plug,
 		.unplug = pci_unplug,
 		.parse = pci_parse,
+		.get_iommu_class = rte_pci_get_iommu_class,
 	},
 	.device_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.device_list),
 	.driver_list = TAILQ_HEAD_INITIALIZER(rte_pci_bus.driver_list),
diff --git a/lib/librte_eal/common/include/rte_bus.h b/lib/librte_eal/common/include/rte_bus.h
index 9e40687e5..70a291a4d 100644
--- a/lib/librte_eal/common/include/rte_bus.h
+++ b/lib/librte_eal/common/include/rte_bus.h
@@ -178,6 +178,20 @@ struct rte_bus_conf {
 	enum rte_bus_scan_mode scan_mode; /**< Scan policy. */
 };
 
+
+/**
+ * Get common iommu class of the all the devices on the bus. The bus may
+ * check that those devices are attached to iommu driver.
+ * If no devices are attached to the bus. The bus may return with don't care
+ * (_DC) value.
+ * Otherwise, The bus will return appropriate _pa or _va iova mode.
+ *
+ * @return
+ *      enum rte_iova_mode value.
+ */
+typedef enum rte_iova_mode (*rte_bus_get_iommu_class_t)(void);
+
+
 /**
  * A structure describing a generic bus.
  */
@@ -191,6 +205,7 @@ struct rte_bus {
 	rte_bus_unplug_t unplug;     /**< Remove single device from driver */
 	rte_bus_parse_t parse;       /**< Parse a device name */
 	struct rte_bus_conf conf;    /**< Bus configuration */
+	rte_bus_get_iommu_class_t get_iommu_class; /**< Get iommu class */
 };
 
 /**
@@ -290,6 +305,16 @@ struct rte_bus *rte_bus_find_by_device(const struct rte_device *dev);
  */
 struct rte_bus *rte_bus_find_by_name(const char *busname);
 
+
+/**
+ * Get the common iommu class of devices bound on to buses available in the
+ * system. The default mode is PA.
+ *
+ * @return
+ *     enum rte_iova_mode value.
+ */
+enum rte_iova_mode rte_bus_get_iommu_class(void);
+
 /**
  * Helper for Bus registration.
  * The constructor has higher priority than PMD constructors.
diff --git a/lib/librte_eal/linuxapp/eal/rte_eal_version.map b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
index bf68f02bc..780539dc7 100644
--- a/lib/librte_eal/linuxapp/eal/rte_eal_version.map
+++ b/lib/librte_eal/linuxapp/eal/rte_eal_version.map
@@ -247,5 +247,6 @@ DPDK_17.11 {
 
 	rte_pci_match;
 	rte_pci_get_iommu_class;
+	rte_bus_get_iommu_class;
 
 } DPDK_17.08;
-- 
2.11.0