pds_core: add the aux client API

Add the client API operations for running adminq commands.
The core registers the client with the FW, then the client
has a context for requesting adminq services.  We expect
to add additional operations for other clients, including
requesting additional private adminqs and IRQs, but don't have
the need yet.
Signed-off-by: Shannon Nelson <shannon.nelson@amd.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/ethernet/amd/pds_core/auxbus.c

@@ -6,6 +6,136 @@
 #include "core.h"
 #include <linux/pds/pds_auxbus.h>
 
+/**
+ * pds_client_register - Link the client to the firmware
+ * @pf_pdev:	ptr to the PF driver struct
+ * @devname:	name that includes service into, e.g. pds_core.vDPA
+ *
+ * Return: 0 on success, or
+ *         negative for error
+ */
+int pds_client_register(struct pci_dev *pf_pdev, char *devname)
+{
+	union pds_core_adminq_comp comp = {};
+	union pds_core_adminq_cmd cmd = {};
+	struct pdsc *pf;
+	int err;
+	u16 ci;
+
+	pf = pci_get_drvdata(pf_pdev);
+	if (pf->state)
+		return -ENXIO;
+
+	cmd.client_reg.opcode = PDS_AQ_CMD_CLIENT_REG;
+	strscpy(cmd.client_reg.devname, devname,
+		sizeof(cmd.client_reg.devname));
+
+	err = pdsc_adminq_post(pf, &cmd, &comp, false);
+	if (err) {
+		dev_info(pf->dev, "register dev_name %s with DSC failed, status %d: %pe\n",
+			 devname, comp.status, ERR_PTR(err));
+		return err;
+	}
+
+	ci = le16_to_cpu(comp.client_reg.client_id);
+	if (!ci) {
+		dev_err(pf->dev, "%s: device returned null client_id\n",
+			__func__);
+		return -EIO;
+	}
+
+	dev_dbg(pf->dev, "%s: device returned client_id %d for %s\n",
+		__func__, ci, devname);
+
+	return ci;
+}
+EXPORT_SYMBOL_GPL(pds_client_register);
+
+/**
+ * pds_client_unregister - Unlink the client from the firmware
+ * @pf_pdev:	ptr to the PF driver struct
+ * @client_id:	id returned from pds_client_register()
+ *
+ * Return: 0 on success, or
+ *         negative for error
+ */
+int pds_client_unregister(struct pci_dev *pf_pdev, u16 client_id)
+{
+	union pds_core_adminq_comp comp = {};
+	union pds_core_adminq_cmd cmd = {};
+	struct pdsc *pf;
+	int err;
+
+	pf = pci_get_drvdata(pf_pdev);
+	if (pf->state)
+		return -ENXIO;
+
+	cmd.client_unreg.opcode = PDS_AQ_CMD_CLIENT_UNREG;
+	cmd.client_unreg.client_id = cpu_to_le16(client_id);
+
+	err = pdsc_adminq_post(pf, &cmd, &comp, false);
+	if (err)
+		dev_info(pf->dev, "unregister client_id %d failed, status %d: %pe\n",
+			 client_id, comp.status, ERR_PTR(err));
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(pds_client_unregister);
+
+/**
+ * pds_client_adminq_cmd - Process an adminq request for the client
+ * @padev:   ptr to the client device
+ * @req:     ptr to buffer with request
+ * @req_len: length of actual struct used for request
+ * @resp:    ptr to buffer where answer is to be copied
+ * @flags:   optional flags from pds_core_adminq_flags
+ *
+ * Return: 0 on success, or
+ *         negative for error
+ *
+ * Client sends pointers to request and response buffers
+ * Core copies request data into pds_core_client_request_cmd
+ * Core sets other fields as needed
+ * Core posts to AdminQ
+ * Core copies completion data into response buffer
+ */
+int pds_client_adminq_cmd(struct pds_auxiliary_dev *padev,
+			  union pds_core_adminq_cmd *req,
+			  size_t req_len,
+			  union pds_core_adminq_comp *resp,
+			  u64 flags)
+{
+	union pds_core_adminq_cmd cmd = {};
+	struct pci_dev *pf_pdev;
+	struct pdsc *pf;
+	size_t cp_len;
+	int err;
+
+	pf_pdev = pci_physfn(padev->vf_pdev);
+	pf = pci_get_drvdata(pf_pdev);
+
+	dev_dbg(pf->dev, "%s: %s opcode %d\n",
+		__func__, dev_name(&padev->aux_dev.dev), req->opcode);
+
+	if (pf->state)
+		return -ENXIO;
+
+	/* Wrap the client's request */
+	cmd.client_request.opcode = PDS_AQ_CMD_CLIENT_CMD;
+	cmd.client_request.client_id = cpu_to_le16(padev->client_id);
+	cp_len = min_t(size_t, req_len, sizeof(cmd.client_request.client_cmd));
+	memcpy(cmd.client_request.client_cmd, req, cp_len);
+
+	err = pdsc_adminq_post(pf, &cmd, resp,
+			       !!(flags & PDS_AQ_FLAG_FASTPOLL));
+	if (err && err != -EAGAIN)
+		dev_info(pf->dev, "client admin cmd failed: %pe\n",
+			 ERR_PTR(err));
+
+	return err;
+}
+EXPORT_SYMBOL_GPL(pds_client_adminq_cmd);
+
 static void pdsc_auxbus_dev_release(struct device *dev)
 {
 	struct pds_auxiliary_dev *padev =
@@ -16,6 +146,7 @@ static void pdsc_auxbus_dev_release(struct device *dev)
 
 static struct pds_auxiliary_dev *pdsc_auxbus_dev_register(struct pdsc *cf,
 							  struct pdsc *pf,
+							  u16 client_id,
 							  char *name)
 {
 	struct auxiliary_device *aux_dev;
@@ -27,6 +158,7 @@ static struct pds_auxiliary_dev *pdsc_auxbus_dev_register(struct pdsc *cf,
 		return ERR_PTR(-ENOMEM);
 
 	padev->vf_pdev = cf->pdev;
+	padev->client_id = client_id;
 
 	aux_dev = &padev->aux_dev;
 	aux_dev->name = name;
@@ -66,8 +198,10 @@ int pdsc_auxbus_dev_del(struct pdsc *cf, struct pdsc *pf)
 
 	padev = pf->vfs[cf->vf_id].padev;
 	if (padev) {
+		pds_client_unregister(pf->pdev, padev->client_id);
 		auxiliary_device_delete(&padev->aux_dev);
 		auxiliary_device_uninit(&padev->aux_dev);
+		padev->client_id = 0;
 	}
 	pf->vfs[cf->vf_id].padev = NULL;
 
@@ -79,7 +213,9 @@ int pdsc_auxbus_dev_add(struct pdsc *cf, struct pdsc *pf)
 {
 	struct pds_auxiliary_dev *padev;
 	enum pds_core_vif_types vt;
+	char devname[PDS_DEVNAME_LEN];
 	u16 vt_support;
+	int client_id;
 	int err = 0;
 
 	mutex_lock(&pf->config_lock);
@@ -101,9 +237,22 @@ int pdsc_auxbus_dev_add(struct pdsc *cf, struct pdsc *pf)
 	      pf->viftype_status[vt].enabled))
 		goto out_unlock;
 
-	padev = pdsc_auxbus_dev_register(cf, pf,
+	/* Need to register with FW and get the client_id before
+	 * creating the aux device so that the aux client can run
+	 * adminq commands as part its probe
+	 */
+	snprintf(devname, sizeof(devname), "%s.%s.%d",
+		 PDS_CORE_DRV_NAME, pf->viftype_status[vt].name, cf->uid);
+	client_id = pds_client_register(pf->pdev, devname);
+	if (client_id < 0) {
+		err = client_id;
+		goto out_unlock;
+	}
+
+	padev = pdsc_auxbus_dev_register(cf, pf, client_id,
 					 pf->viftype_status[vt].name);
 	if (IS_ERR(padev)) {
+		pds_client_unregister(pf->pdev, client_id);
 		err = PTR_ERR(padev);
 		goto out_unlock;
 	}

include/linux/pds/pds_auxbus.h

@@ -11,4 +11,10 @@ struct pds_auxiliary_dev {
 	struct pci_dev *vf_pdev;
 	u16 client_id;
 };
+
+int pds_client_adminq_cmd(struct pds_auxiliary_dev *padev,
+			  union pds_core_adminq_cmd *req,
+			  size_t req_len,
+			  union pds_core_adminq_comp *resp,
+			  u64 flags);
 #endif /* _PDSC_AUXBUS_H_ */

include/linux/pds/pds_common.h

@@ -61,4 +61,6 @@ enum pds_core_logical_qtype {
 };
 
 void *pdsc_get_pf_struct(struct pci_dev *vf_pdev);
+int pds_client_register(struct pci_dev *pf_pdev, char *devname);
+int pds_client_unregister(struct pci_dev *pf_pdev, u16 client_id);
 #endif /* _PDS_COMMON_H_ */