vdpa/snet: support the suspend vDPA callback

When suspend is called, the driver sends a suspend command to the DPU
through the control mechanism.

Signed-off-by: Alvaro Karsz <[e-mail]>
Message-Id: <[e-mail]>
Signed-off-by: Michael S. Tsirkin <[e-mail]>
Acked-by: Jason Wang <[e-mail]>

drivers/vdpa/solidrun/snet_ctrl.c

···
 enum snet_ctrl_opcodes {
 	SNET_CTRL_OP_DESTROY = 1,
 	SNET_CTRL_OP_READ_VQ_STATE,
+	SNET_CTRL_OP_SUSPEND,
 };
 
 #define SNET_CTRL_TIMEOUT	        2000000
···
 {
 	return snet_ctrl_read_from_dpu(snet, SNET_CTRL_OP_READ_VQ_STATE, idx, state,
 				       sizeof(*state));
+}
+
+int snet_suspend_dev(struct snet *snet)
+{
+	return snet_send_ctrl_msg(snet, SNET_CTRL_OP_SUSPEND, 0);
 }

drivers/vdpa/solidrun/snet_main.c

···
 		iowrite8(*buf_ptr++, cfg_ptr + i);
 }
 
+static int snet_suspend(struct vdpa_device *vdev)
+{
+	struct snet *snet = vdpa_to_snet(vdev);
+	int ret;
+
+	ret = snet_suspend_dev(snet);
+	if (ret)
+		SNET_ERR(snet->pdev, "SNET[%u] suspend failed, err: %d\n", snet->sid, ret);
+	else
+		SNET_DBG(snet->pdev, "Suspend SNET[%u] device\n", snet->sid);
+
+	return ret;
+}
+
 static const struct vdpa_config_ops snet_config_ops = {
 	.set_vq_address         = snet_set_vq_address,
 	.set_vq_num             = snet_set_vq_num,
···
 	.set_status             = snet_set_status,
 	.get_config             = snet_get_config,
 	.set_config             = snet_set_config,
+	.suspend		= snet_suspend,
 };
 
 static int psnet_open_pf_bar(struct pci_dev *pdev, struct psnet *psnet)

drivers/vdpa/solidrun/snet_vdpa.h

···
 void snet_ctrl_clear(struct snet *snet);
 int snet_destroy_dev(struct snet *snet);
 int snet_read_vq_state(struct snet *snet, u16 idx, struct vdpa_vq_state *state);
+int snet_suspend_dev(struct snet *snet);
 
 #endif //_SNET_VDPA_H_