enic: add devcmd2

devcmd is an interface for driver to communicate with fw/adaptor. It
involves writing data to hardware registers and waiting for the result.
This mechanism does not scale well. The queuing of "no wait" devcmds is
done in firmware memory rather than on the host. Firmware memory is a
rather more scarce and valuable resource than host memory. A devcmd storm
from one vf can disrupt the service on other pf/vf. The lack of flow
control allows for possible denial of server from one VM to another.

Devcmd2 uses work queue to post the devcmds, just like tx work queue. This
allows better flow control.

Initialize devcmd2, if fails we fall back to devcmd1.

Also change the driver version.

Signed-off-by: N V V Satyanarayana Reddy <nalreddy@cisco.com>
Signed-off-by: Govindarajulu Varadarajan <_govind@gmx.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 181 insertions, 7 deletions

diff --git a/drivers/net/ethernet/cisco/enic/vnic_dev.c b/drivers/net/ethernet/cisco/enic/vnic_dev.c
index 52bfb3a27e95..ff2da7ece7d4 100644
--- a/drivers/net/ethernet/cisco/enic/vnic_dev.c
+++ b/drivers/net/ethernet/cisco/enic/vnic_dev.c
@@ -27,6 +27,7 @@
 #include "vnic_resource.h"
 #include "vnic_devcmd.h"
 #include "vnic_dev.h"
+#include "vnic_wq.h"
 #include "vnic_stats.h"
 #include "enic.h"
 
@@ -113,6 +114,7 @@ static int vnic_dev_discover_res(struct vnic_dev *vdev,
 			break;
 		case RES_TYPE_INTR_PBA_LEGACY:
 		case RES_TYPE_DEVCMD:
+		case RES_TYPE_DEVCMD2:
 			len = count;
 			break;
 		default:
@@ -292,6 +294,156 @@ static int _vnic_dev_cmd(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd,
 	return -ETIMEDOUT;
 }
 
+static int _vnic_dev_cmd2(struct vnic_dev *vdev, enum vnic_devcmd_cmd cmd,
+			  int wait)
+{
+	struct devcmd2_controller *dc2c = vdev->devcmd2;
+	struct devcmd2_result *result = dc2c->result + dc2c->next_result;
+	unsigned int i;
+	int delay, err;
+	u32 fetch_index, posted, new_posted;
+
+	posted = ioread32(&dc2c->wq_ctrl->posted_index);
+	fetch_index = ioread32(&dc2c->wq_ctrl->fetch_index);
+
+	if (posted == 0xFFFFFFFF || fetch_index == 0xFFFFFFFF)
+		return -ENODEV;
+
+	new_posted = (posted + 1) % DEVCMD2_RING_SIZE;
+
+	if (new_posted == fetch_index) {
+		vdev_neterr("devcmd2 %d: wq is full. fetch index: %u, posted index: %u\n",
+			    _CMD_N(cmd), fetch_index, posted);
+		return -EBUSY;
+	}
+	dc2c->cmd_ring[posted].cmd = cmd;
+	dc2c->cmd_ring[posted].flags = 0;
+
+	if ((_CMD_FLAGS(cmd) & _CMD_FLAGS_NOWAIT))
+		dc2c->cmd_ring[posted].flags |= DEVCMD2_FNORESULT;
+	if (_CMD_DIR(cmd) & _CMD_DIR_WRITE)
+		for (i = 0; i < VNIC_DEVCMD_NARGS; i++)
+			dc2c->cmd_ring[posted].args[i] = vdev->args[i];
+
+	/* Adding write memory barrier prevents compiler and/or CPU reordering,
+	 * thus avoiding descriptor posting before descriptor is initialized.
+	 * Otherwise, hardware can read stale descriptor fields.
+	 */
+	wmb();
+	iowrite32(new_posted, &dc2c->wq_ctrl->posted_index);
+
+	if (dc2c->cmd_ring[posted].flags & DEVCMD2_FNORESULT)
+		return 0;
+
+	for (delay = 0; delay < wait; delay++) {
+		if (result->color == dc2c->color) {
+			dc2c->next_result++;
+			if (dc2c->next_result == dc2c->result_size) {
+				dc2c->next_result = 0;
+				dc2c->color = dc2c->color ? 0 : 1;
+			}
+			if (result->error) {
+				err = result->error;
+				if (err != ERR_ECMDUNKNOWN ||
+				    cmd != CMD_CAPABILITY)
+					vdev_neterr("Error %d devcmd %d\n",
+						    err, _CMD_N(cmd));
+				return -err;
+			}
+			if (_CMD_DIR(cmd) & _CMD_DIR_READ)
+				for (i = 0; i < VNIC_DEVCMD2_NARGS; i++)
+					vdev->args[i] = result->results[i];
+
+			return 0;
+		}
+		udelay(100);
+	}
+
+	vdev_neterr("devcmd %d timed out\n", _CMD_N(cmd));
+
+	return -ETIMEDOUT;
+}
+
+static int vnic_dev_init_devcmd1(struct vnic_dev *vdev)
+{
+	vdev->devcmd = vnic_dev_get_res(vdev, RES_TYPE_DEVCMD, 0);
+	if (!vdev->devcmd)
+		return -ENODEV;
+	vdev->devcmd_rtn = _vnic_dev_cmd;
+
+	return 0;
+}
+
+static int vnic_dev_init_devcmd2(struct vnic_dev *vdev)
+{
+	int err;
+	unsigned int fetch_index;
+
+	if (vdev->devcmd2)
+		return 0;
+
+	vdev->devcmd2 = kzalloc(sizeof(*vdev->devcmd2), GFP_KERNEL);
+	if (!vdev->devcmd2)
+		return -ENOMEM;
+
+	vdev->devcmd2->color = 1;
+	vdev->devcmd2->result_size = DEVCMD2_RING_SIZE;
+	err = vnic_wq_devcmd2_alloc(vdev, &vdev->devcmd2->wq, DEVCMD2_RING_SIZE,
+				    DEVCMD2_DESC_SIZE);
+	if (err)
+		goto err_free_devcmd2;
+
+	fetch_index = ioread32(&vdev->devcmd2->wq.ctrl->fetch_index);
+	if (fetch_index == 0xFFFFFFFF) { /* check for hardware gone  */
+		vdev_err("Fatal error in devcmd2 init - hardware surprise removal");
+
+		return -ENODEV;
+	}
+
+	vnic_wq_init_start(&vdev->devcmd2->wq, 0, fetch_index, fetch_index, 0,
+			   0);
+	vnic_wq_enable(&vdev->devcmd2->wq);
+
+	err = vnic_dev_alloc_desc_ring(vdev, &vdev->devcmd2->results_ring,
+				       DEVCMD2_RING_SIZE, DEVCMD2_DESC_SIZE);
+	if (err)
+		goto err_free_wq;
+
+	vdev->devcmd2->result = vdev->devcmd2->results_ring.descs;
+	vdev->devcmd2->cmd_ring = vdev->devcmd2->wq.ring.descs;
+	vdev->devcmd2->wq_ctrl = vdev->devcmd2->wq.ctrl;
+	vdev->args[0] = (u64)vdev->devcmd2->results_ring.base_addr |
+			VNIC_PADDR_TARGET;
+	vdev->args[1] = DEVCMD2_RING_SIZE;
+
+	err = _vnic_dev_cmd2(vdev, CMD_INITIALIZE_DEVCMD2, 1000);
+	if (err)
+		goto err_free_desc_ring;
+
+	vdev->devcmd_rtn = _vnic_dev_cmd2;
+
+	return 0;
+
+err_free_desc_ring:
+	vnic_dev_free_desc_ring(vdev, &vdev->devcmd2->results_ring);
+err_free_wq:
+	vnic_wq_disable(&vdev->devcmd2->wq);
+	vnic_wq_free(&vdev->devcmd2->wq);
+err_free_devcmd2:
+	kfree(vdev->devcmd2);
+	vdev->devcmd2 = NULL;
+
+	return err;
+}
+
+static void vnic_dev_deinit_devcmd2(struct vnic_dev *vdev)
+{
+	vnic_dev_free_desc_ring(vdev, &vdev->devcmd2->results_ring);
+	vnic_wq_disable(&vdev->devcmd2->wq);
+	vnic_wq_free(&vdev->devcmd2->wq);
+	kfree(vdev->devcmd2);
+}
+
 static int vnic_dev_cmd_proxy(struct vnic_dev *vdev,
 	enum vnic_devcmd_cmd proxy_cmd, enum vnic_devcmd_cmd cmd,
 	u64 *a0, u64 *a1, int wait)
@@ -306,7 +458,7 @@ static int vnic_dev_cmd_proxy(struct vnic_dev *vdev,
 	vdev->args[2] = *a0;
 	vdev->args[3] = *a1;
 
-	err = _vnic_dev_cmd(vdev, proxy_cmd, wait);
+	err = vdev->devcmd_rtn(vdev, proxy_cmd, wait);
 	if (err)
 		return err;
 
@@ -334,7 +486,7 @@ static int vnic_dev_cmd_no_proxy(struct vnic_dev *vdev,
 	vdev->args[0] = *a0;
 	vdev->args[1] = *a1;
 
-	err = _vnic_dev_cmd(vdev, cmd, wait);
+	err = vdev->devcmd_rtn(vdev, cmd, wait);
 
 	*a0 = vdev->args[0];
 	*a1 = vdev->args[1];
@@ -797,7 +949,7 @@ int vnic_dev_intr_coal_timer_info(struct vnic_dev *vdev)
 	memset(vdev->args, 0, sizeof(vdev->args));
 
 	if (vnic_dev_capable(vdev, CMD_INTR_COAL_CONVERT))
-		err = _vnic_dev_cmd(vdev, CMD_INTR_COAL_CONVERT, wait);
+		err = vdev->devcmd_rtn(vdev, CMD_INTR_COAL_CONVERT, wait);
 	else
 		err = ERR_ECMDUNKNOWN;
 
@@ -897,6 +1049,9 @@ void vnic_dev_unregister(struct vnic_dev *vdev)
 			pci_free_consistent(vdev->pdev,
 				sizeof(struct vnic_devcmd_fw_info),
 				vdev->fw_info, vdev->fw_info_pa);
+		if (vdev->devcmd2)
+			vnic_dev_deinit_devcmd2(vdev);
+
 		kfree(vdev);
 	}
 }
@@ -918,10 +1073,6 @@ struct vnic_dev *vnic_dev_register(struct vnic_dev *vdev,
 	if (vnic_dev_discover_res(vdev, bar, num_bars))
 		goto err_out;
 
-	vdev->devcmd = vnic_dev_get_res(vdev, RES_TYPE_DEVCMD, 0);
-	if (!vdev->devcmd)
-		goto err_out;
-
 	return vdev;
 
 err_out:
@@ -936,6 +1087,29 @@ struct pci_dev *vnic_dev_get_pdev(struct vnic_dev *vdev)
 }
 EXPORT_SYMBOL(vnic_dev_get_pdev);
 
+int vnic_devcmd_init(struct vnic_dev *vdev)
+{
+	int err;
+	void *res;
+
+	res = vnic_dev_get_res(vdev, RES_TYPE_DEVCMD2, 0);
+	if (res) {
+		err = vnic_dev_init_devcmd2(vdev);
+		if (err)
+			vdev_warn("DEVCMD2 init failed: %d, Using DEVCMD1",
+				  err);
+		else
+			return 0;
+	} else {
+		vdev_warn("DEVCMD2 resource not found (old firmware?) Using DEVCMD1\n");
+	}
+	err = vnic_dev_init_devcmd1(vdev);
+	if (err)
+		vdev_err("DEVCMD1 initialization failed: %d", err);
+
+	return err;
+}
+
 int vnic_dev_init_prov2(struct vnic_dev *vdev, u8 *buf, u32 len)
 {
 	u64 a0, a1 = len;