[PATCH v5 04/15] coco: host: arm64: Add RMM pdev stop and destroy helper

["Aneesh Kumar K.V (Arm)" <aneesh.kumar@kernel.org>]

Add the host-side helper needed to tear down an RMM pdev object once later
disconnect and error paths are wired up.

Describe RMI_PDEV_STOP and RMI_PDEV_DESTROY, add the PDEV_STOP SMCCC
wrapper, and issue PDEV_DESTROY through the SRO helper. The new teardown
helper stops the pdev, drives device communication until RMM reports
RMI_PDEV_STOPPED, destroys the RMM object, releases cached PF0
device-communication state, and undelegates the backing granule.

No caller is added here; this prepares the teardown side of the RMM pdev
lifecycle for the follow-up patches that connect it to IDE stream
disconnect.

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 drivers/virt/coco/arm-cca-host/rmi-da.c | 47 ++++++++++++++++++++++++-
 drivers/virt/coco/arm-cca-host/rmi-da.h |  1 +
 include/linux/arm-rmi-cmds.h            |  9 +++++
 3 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/drivers/virt/coco/arm-cca-host/rmi-da.c b/drivers/virt/coco/arm-cca-host/rmi-da.c
index 495a3bd2798f..7a72e8eead90 100644
--- a/drivers/virt/coco/arm-cca-host/rmi-da.c
+++ b/drivers/virt/coco/arm-cca-host/rmi-da.c
@@ -394,7 +394,7 @@ static void pdev_state_transition_workfn(struct work_struct *work)
 	WARN_ON(state != setup_work->target_state);
 }
 
-static int __maybe_unused submit_pdev_state_transition_work(struct pci_dev *pdev,
+static int submit_pdev_state_transition_work(struct pci_dev *pdev,
 		enum rmi_pdev_state target_state)
 {
 	enum rmi_pdev_state state;
@@ -420,3 +420,48 @@ static int __maybe_unused submit_pdev_state_transition_work(struct pci_dev *pdev
 		return -1;
 	return 0;
 }
+
+static inline int rmi_pdev_destroy(unsigned long pdev_phys,
+		unsigned long *rmi_ret)
+{
+	struct rmi_sro_state *sro __free(kfree) = kmalloc_obj(*sro);
+	if (!sro)
+		return -ENOMEM;
+
+	*rmi_ret = rmi_sro_memxfer_cmd(sro, GFP_KERNEL,
+				       SMC_RMI_PDEV_DESTROY, pdev_phys);
+
+	return 0;
+}
+
+void cca_pdev_stop_and_destroy(struct pci_dev *pdev)
+{
+	int ret;
+	unsigned long rmi_ret;
+	struct cca_host_pdev_dsc *pdev_dsc = to_cca_pdev_dsc(pdev);
+	struct cca_host_pf0_ep_dsc *pf0_ep_dsc = to_cca_pf0_ep_dsc(pdev);
+	phys_addr_t rmm_pdev_phys = virt_to_phys(pdev_dsc->rmm_pdev);
+
+	if (WARN_ON(rmi_pdev_stop(rmm_pdev_phys)))
+		return;
+
+	ret = submit_pdev_state_transition_work(pdev, RMI_PDEV_STOPPED);
+	if (ret)
+		return;
+
+	ret = rmi_pdev_destroy(rmm_pdev_phys, &rmi_ret);
+	if (WARN_ON(ret || rmi_ret))
+		return;
+
+	if (pf0_ep_dsc) {
+		kfree(pf0_ep_dsc->cert_chain.public_key);
+		kvfree(pf0_ep_dsc->cert_chain.cache);
+		kvfree(pf0_ep_dsc->vca);
+		pf0_ep_dsc->cert_chain.cache = NULL;
+		pf0_ep_dsc->vca = NULL;
+	}
+
+	if (!rmi_undelegate_page(rmm_pdev_phys))
+		free_page((unsigned long)pdev_dsc->rmm_pdev);
+	pdev_dsc->rmm_pdev = NULL;
+}
diff --git a/drivers/virt/coco/arm-cca-host/rmi-da.h b/drivers/virt/coco/arm-cca-host/rmi-da.h
index 07034b034b53..f3bd106c8a54 100644
--- a/drivers/virt/coco/arm-cca-host/rmi-da.h
+++ b/drivers/virt/coco/arm-cca-host/rmi-da.h
@@ -133,5 +133,6 @@ static inline struct cca_host_comm_data *to_cca_comm_data(struct pci_dev *pdev)
 }
 
 int cca_pdev_create(struct pci_dev *pdev);
+void cca_pdev_stop_and_destroy(struct pci_dev *pdev);
 
 #endif
diff --git a/include/linux/arm-rmi-cmds.h b/include/linux/arm-rmi-cmds.h
index c2fc80dd19cc..f947b2f4909a 100644
--- a/include/linux/arm-rmi-cmds.h
+++ b/include/linux/arm-rmi-cmds.h
@@ -706,4 +706,13 @@ static inline unsigned long rmi_pdev_abort(unsigned long pdev_phys)
 	return res.a0;
 }
 
+static inline unsigned long rmi_pdev_stop(unsigned long pdev_phys)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RMI_PDEV_STOP, pdev_phys, &res);
+
+	return res.a0;
+}
+
 #endif
-- 
2.43.0