enic: Add support to configure hardware interrupt coalesce timers in a platform independent way

enic driver and the underlying hardware use different units for representing the interrupt coalesce timer.
Driver converts the interrupt coalesce timer in usec to hardware cycles while setting the relevant hardware
registers. The conversion factor can be different for each of the adapter hardware types. So it is dynamically
learnt from the adapter firmware using the devcmd CMD_INTR_COAL_CONVERT. This allows the driver to configure
the hardware interrupt coalesce timers in a platform independent way.

Signed-off-by: Danny Guo <dannguo@cisco.com>
Signed-off-by: Vasanthy Kolluri <vkolluri@cisco.com>
Signed-off-by: Roopa Prabhu <roprabhu@cisco.com>
Signed-off-by: David Wang <dwang2@cisco.com>
Signed-off-by: David S. Miller <davem@conan.davemloft.net>

1 files changed, 60 insertions, 0 deletions

diff --git a/drivers/net/enic/vnic_dev.c b/drivers/net/enic/vnic_dev.c
index 68f24ae860ae..8c4c8cf486f6 100644
--- a/drivers/net/enic/vnic_dev.c
+++ b/drivers/net/enic/vnic_dev.c
@@ -40,6 +40,12 @@ struct vnic_res {
         unsigned int count;
 };
 
+struct vnic_intr_coal_timer_info {
+        u32 mul;
+        u32 div;
+        u32 max_usec;
+};
+
 struct vnic_dev {
         void *priv;
         struct pci_dev *pdev;
@@ -58,6 +64,7 @@ struct vnic_dev {
         enum vnic_proxy_type proxy;
         u32 proxy_index;
         u64 args[VNIC_DEVCMD_NARGS];
+        struct vnic_intr_coal_timer_info intr_coal_timer_info;
 };
 
 #define VNIC_MAX_RES_HDR_SIZE \
@@ -794,6 +801,42 @@ int vnic_dev_deinit(struct vnic_dev *vdev)
         return vnic_dev_cmd(vdev, CMD_DEINIT, &a0, &a1, wait);
 }
 
+void vnic_dev_intr_coal_timer_info_default(struct vnic_dev *vdev)
+{
+        /* Default: hardware intr coal timer is in units of 1.5 usecs */
+        vdev->intr_coal_timer_info.mul = 2;
+        vdev->intr_coal_timer_info.div = 3;
+        vdev->intr_coal_timer_info.max_usec =
+                vnic_dev_intr_coal_timer_hw_to_usec(vdev, 0xffff);
+}
+
+int vnic_dev_intr_coal_timer_info(struct vnic_dev *vdev)
+{
+        int wait = 1000;
+        int err;
+
+        memset(vdev->args, 0, sizeof(vdev->args));
+
+        err = _vnic_dev_cmd(vdev, CMD_INTR_COAL_CONVERT, wait);
+
+        /* Use defaults when firmware doesn't support the devcmd at all or
+         * supports it for only specific hardware
+         */
+        if ((err == ERR_ECMDUNKNOWN) ||
+                (!err && !(vdev->args[0] && vdev->args[1] && vdev->args[2]))) {
+                pr_warning("Using default conversion factor for "
+                        "interrupt coalesce timer\n");
+                vnic_dev_intr_coal_timer_info_default(vdev);
+                return 0;
+        }
+
+        vdev->intr_coal_timer_info.mul = (u32) vdev->args[0];
+        vdev->intr_coal_timer_info.div = (u32) vdev->args[1];
+        vdev->intr_coal_timer_info.max_usec = (u32) vdev->args[2];
+
+        return err;
+}
+
 int vnic_dev_link_status(struct vnic_dev *vdev)
 {
         if (!vnic_dev_notify_ready(vdev))
@@ -838,6 +881,23 @@ enum vnic_dev_intr_mode vnic_dev_get_intr_mode(
         return vdev->intr_mode;
 }
 
+u32 vnic_dev_intr_coal_timer_usec_to_hw(struct vnic_dev *vdev, u32 usec)
+{
+        return (usec * vdev->intr_coal_timer_info.mul) /
+                vdev->intr_coal_timer_info.div;
+}
+
+u32 vnic_dev_intr_coal_timer_hw_to_usec(struct vnic_dev *vdev, u32 hw_cycles)
+{
+        return (hw_cycles * vdev->intr_coal_timer_info.div) /
+                vdev->intr_coal_timer_info.mul;
+}
+
+u32 vnic_dev_get_intr_coal_timer_max(struct vnic_dev *vdev)
+{
+        return vdev->intr_coal_timer_info.max_usec;
+}
+
 void vnic_dev_unregister(struct vnic_dev *vdev)
 {
         if (vdev) {