[dpdk-dev] [PATCH 1/3] uio: fix irq handling with igb_uio

[Stephen Hemminger]

The introduction of uio_pci_generic broke interrupt handling with
igb_uio. The igb_uio device uses the kernel read/write method to
enable disable IRQ's; the uio_pci_generic has to use PCI intx
config read/write to enable disable interrupts.

Since igb_uio uses MSI-X the PCI intx config read/write won't
work.

Signed-off-by: Stephen Hemminger <stephen at networkplumber.org>
---
 lib/librte_eal/linuxapp/eal/eal_interrupts.c       | 40 ++++++++++++++++++++--
 lib/librte_eal/linuxapp/eal/eal_pci_uio.c          | 15 +++++---
 .../linuxapp/eal/include/exec-env/rte_interrupts.h |  3 +-
 3 files changed, 50 insertions(+), 8 deletions(-)

diff --git a/lib/librte_eal/linuxapp/eal/eal_interrupts.c b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
index 66deda2..3a84b3c 100644
--- a/lib/librte_eal/linuxapp/eal/eal_interrupts.c
+++ b/lib/librte_eal/linuxapp/eal/eal_interrupts.c
@@ -361,7 +361,7 @@ vfio_disable_msix(struct rte_intr_handle *intr_handle) {
 #endif
 
 static int
-uio_intr_disable(struct rte_intr_handle *intr_handle)
+uio_intx_intr_disable(struct rte_intr_handle *intr_handle)
 {
 	unsigned char command_high;
 
@@ -385,7 +385,7 @@ uio_intr_disable(struct rte_intr_handle *intr_handle)
 }
 
 static int
-uio_intr_enable(struct rte_intr_handle *intr_handle)
+uio_intx_intr_enable(struct rte_intr_handle *intr_handle)
 {
 	unsigned char command_high;
 
@@ -408,6 +408,34 @@ uio_intr_enable(struct rte_intr_handle *intr_handle)
 	return 0;
 }
 
+static int
+uio_intr_disable(struct rte_intr_handle *intr_handle)
+{
+	const int value = 0;
+
+	if (write(intr_handle->fd, &value, sizeof(value)) < 0) {
+		RTE_LOG(ERR, EAL,
+			"Error disabling interrupts for fd %d (%s)\n",
+			intr_handle->fd, strerror(errno));
+		return -1;
+	}
+	return 0;
+}
+
+static int
+uio_intr_enable(struct rte_intr_handle *intr_handle)
+{
+	const int value = 1;
+
+	if (write(intr_handle->fd, &value, sizeof(value)) < 0) {
+		RTE_LOG(ERR, EAL,
+			"Error enabling interrupts for fd %d (%s)\n",
+			intr_handle->fd, strerror(errno));
+		return -1;
+	}
+	return 0;
+}
+
 int
 rte_intr_callback_register(struct rte_intr_handle *intr_handle,
 			rte_intr_callback_fn cb, void *cb_arg)
@@ -556,6 +584,10 @@ rte_intr_enable(struct rte_intr_handle *intr_handle)
 		if (uio_intr_enable(intr_handle))
 			return -1;
 		break;
+	case RTE_INTR_HANDLE_UIO_INTX:
+		if (uio_intx_intr_enable(intr_handle))
+			return -1;
+		break;
 	/* not used at this moment */
 	case RTE_INTR_HANDLE_ALARM:
 		return -1;
@@ -596,6 +628,10 @@ rte_intr_disable(struct rte_intr_handle *intr_handle)
 		if (uio_intr_disable(intr_handle))
 			return -1;
 		break;
+	case RTE_INTR_HANDLE_UIO_INTX:
+		if (uio_intx_intr_disable(intr_handle))
+			return -1;
+		break;
 	/* not used at this moment */
 	case RTE_INTR_HANDLE_ALARM:
 		return -1;
diff --git a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
index 2d1c69b..b5116a7 100644
--- a/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
+++ b/lib/librte_eal/linuxapp/eal/eal_pci_uio.c
@@ -299,7 +299,6 @@ pci_uio_map_resource(struct rte_pci_device *dev)
 			devname, strerror(errno));
 		return -1;
 	}
-	dev->intr_handle.type = RTE_INTR_HANDLE_UIO;
 
 	snprintf(cfgname, sizeof(cfgname),
 			"/sys/class/uio/uio%u/device/config", uio_num);
@@ -310,10 +309,16 @@ pci_uio_map_resource(struct rte_pci_device *dev)
 		return -1;
 	}
 
-	/* set bus master that is not done by uio_pci_generic */
-	if (pci_uio_set_bus_master(dev->intr_handle.uio_cfg_fd)) {
-		RTE_LOG(ERR, EAL, "Cannot set up bus mastering!\n");
-		return -1;
+	if (dev->kdrv == RTE_KDRV_IGB_UIO)
+		dev->intr_handle.type = RTE_INTR_HANDLE_UIO;
+	else {
+		dev->intr_handle.type = RTE_INTR_HANDLE_UIO_INTX;
+
+		/* set bus master that is not done by uio_pci_generic */
+		if (pci_uio_set_bus_master(dev->intr_handle.uio_cfg_fd)) {
+			RTE_LOG(ERR, EAL, "Cannot set up bus mastering!\n");
+			return -1;
+		}
 	}
 
 	/* allocate the mapping details for secondary processes*/
diff --git a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
index 6a159c7..bdeb3fc 100644
--- a/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
+++ b/lib/librte_eal/linuxapp/eal/include/exec-env/rte_interrupts.h
@@ -40,7 +40,8 @@
 
 enum rte_intr_handle_type {
 	RTE_INTR_HANDLE_UNKNOWN = 0,
-	RTE_INTR_HANDLE_UIO,      /**< uio device handle */
+	RTE_INTR_HANDLE_UIO,          /**< uio device handle */
+	RTE_INTR_HANDLE_UIO_INTX,     /**< uio generic handle */
 	RTE_INTR_HANDLE_VFIO_LEGACY,  /**< vfio device handle (legacy) */
 	RTE_INTR_HANDLE_VFIO_MSI,     /**< vfio device handle (MSI) */
 	RTE_INTR_HANDLE_VFIO_MSIX,    /**< vfio device handle (MSIX) */
-- 
2.1.4