[RFC PATCH v1 25/38] cca: guest: arm64: Realm device lock support

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

Writing 1 to 'tsm/lock' will initiate the TDISP lock sequence.

Signed-off-by: Aneesh Kumar K.V (Arm) <aneesh.kumar@kernel.org>
---
 arch/arm64/include/asm/rsi_cmds.h         | 32 +++++++++++++-
 arch/arm64/include/asm/rsi_smc.h          |  5 +++
 drivers/virt/coco/arm-cca-guest/Makefile  |  2 +-
 drivers/virt/coco/arm-cca-guest/arm-cca.c | 18 ++++++++
 drivers/virt/coco/arm-cca-guest/rsi-da.c  | 52 +++++++++++++++++++++++
 drivers/virt/coco/arm-cca-guest/rsi-da.h  |  3 +-
 6 files changed, 108 insertions(+), 4 deletions(-)
 create mode 100644 drivers/virt/coco/arm-cca-guest/rsi-da.c

diff --git a/arch/arm64/include/asm/rsi_cmds.h b/arch/arm64/include/asm/rsi_cmds.h
index d4834baeef1b..b9c4b8ff5631 100644
--- a/arch/arm64/include/asm/rsi_cmds.h
+++ b/arch/arm64/include/asm/rsi_cmds.h
@@ -172,8 +172,36 @@ static inline int rsi_features(unsigned long index, unsigned long *out)
 
 	arm_smccc_1_1_invoke(SMC_RSI_FEATURES, index, &res);
 
-	if (out)
-		*out = res.a1;
+	*out = res.a1;
+	return res.a0;
+}
+
+static inline unsigned long rsi_rdev_get_instance_id(unsigned long vdev_id, unsigned long *inst_id)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RSI_RDEV_GET_INSTANCE_ID, vdev_id, &res);
+
+	*inst_id = res.a1;
+	return res.a0;
+}
+
+static inline unsigned long __rsi_rdev_lock(unsigned long vdev_id, unsigned long inst_id)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RSI_RDEV_LOCK, vdev_id, inst_id, &res);
+
+	return res.a0;
+}
+
+
+static inline unsigned long rsi_rdev_continue(unsigned long vdev_id, unsigned long inst_id)
+{
+	struct arm_smccc_res res;
+
+	arm_smccc_1_1_invoke(SMC_RSI_RDEV_CONTINUE, vdev_id, inst_id, &res);
+
 	return res.a0;
 }
 
diff --git a/arch/arm64/include/asm/rsi_smc.h b/arch/arm64/include/asm/rsi_smc.h
index 8e486cdef9eb..44b583ab6d67 100644
--- a/arch/arm64/include/asm/rsi_smc.h
+++ b/arch/arm64/include/asm/rsi_smc.h
@@ -191,4 +191,9 @@ struct realm_config {
  */
 #define SMC_RSI_HOST_CALL			SMC_RSI_FID(0x199)
 
+#define SMC_RSI_RDEV_GET_INSTANCE_ID		SMC_RSI_FID(0x19c)
+#define SMC_RSI_RDEV_CONTINUE			SMC_RSI_FID(0x1a4)
+
+#define SMC_RSI_RDEV_LOCK			SMC_RSI_FID(0x1a9)
+
 #endif /* __ASM_RSI_SMC_H_ */
diff --git a/drivers/virt/coco/arm-cca-guest/Makefile b/drivers/virt/coco/arm-cca-guest/Makefile
index 609462ea9438..341c7b37d610 100644
--- a/drivers/virt/coco/arm-cca-guest/Makefile
+++ b/drivers/virt/coco/arm-cca-guest/Makefile
@@ -2,4 +2,4 @@
 #
 obj-$(CONFIG_ARM_CCA_GUEST) += arm-cca-guest.o
 
-arm-cca-guest-$(CONFIG_TSM) +=  arm-cca.o
+arm-cca-guest-$(CONFIG_TSM) +=  arm-cca.o rsi-da.o
diff --git a/drivers/virt/coco/arm-cca-guest/arm-cca.c b/drivers/virt/coco/arm-cca-guest/arm-cca.c
index 3adbbd67e06e..2c0190bcb2a9 100644
--- a/drivers/virt/coco/arm-cca-guest/arm-cca.c
+++ b/drivers/virt/coco/arm-cca-guest/arm-cca.c
@@ -220,9 +220,27 @@ static void cca_tsm_pci_remove(struct pci_tsm *tsm)
 	kfree(cca_dsc);
 }
 
+static int cca_tsm_lock(struct pci_dev *pdev)
+{
+	unsigned long ret;
+
+	ret = rsi_device_lock(pdev);
+	if (ret) {
+		pci_err(pdev, "failed to lock the device (%lu)\n", ret);
+		return -EIO;
+	}
+	return 0;
+}
+
+static void cca_tsm_unlock(struct pci_dev *pdev)
+{
+}
+
 static const struct pci_tsm_ops cca_pci_ops = {
 	.probe = cca_tsm_pci_probe,
 	.remove = cca_tsm_pci_remove,
+	.lock = cca_tsm_lock,
+	.unlock = cca_tsm_unlock,
 };
 
 static void cca_tsm_unregister(void *tsm)
diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.c b/drivers/virt/coco/arm-cca-guest/rsi-da.c
new file mode 100644
index 000000000000..097cf52ee199
--- /dev/null
+++ b/drivers/virt/coco/arm-cca-guest/rsi-da.c
@@ -0,0 +1,52 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2025 ARM Ltd.
+ */
+
+#include <linux/pci.h>
+#include <asm/rsi_cmds.h>
+
+#include "rsi-da.h"
+
+#define PCI_TDISP_MESSAGE_VERSION_10	0x10
+
+static inline unsigned long rsi_rdev_lock(struct pci_dev *pdev,
+					  unsigned long vdev_id, unsigned long inst_id)
+{
+	unsigned long ret;
+
+	ret = __rsi_rdev_lock(vdev_id, inst_id);
+	if (ret != RSI_SUCCESS)
+		return ret;
+
+	do {
+		ret = rsi_rdev_continue(vdev_id, inst_id);
+	} while (ret == RSI_INCOMPLETE);
+	if (ret != RSI_SUCCESS) {
+		pci_err(pdev, "failed to communicate with the device (%lu)\n", ret);
+		return ret;
+	}
+	return RSI_SUCCESS;
+}
+
+int rsi_device_lock(struct pci_dev *pdev)
+{
+	unsigned long ret;
+	struct cca_guest_dsc *dsm = to_cca_guest_dsc(pdev);
+	int vdev_id = (pci_domain_nr(pdev->bus) << 16) |
+		PCI_DEVID(pdev->bus->number, pdev->devfn);
+
+	ret = rsi_rdev_get_instance_id(vdev_id, &dsm->instance_id);
+	if (ret != RSI_SUCCESS) {
+		pci_err(pdev, "failed to get the device instance id (%lu)\n", ret);
+		return -EIO;
+	}
+
+	ret = rsi_rdev_lock(pdev, vdev_id, dsm->instance_id);
+	if (ret != RSI_SUCCESS) {
+		pci_err(pdev, "failed to lock the device (%lu)\n", ret);
+		return -EIO;
+	}
+
+	return ret;
+}
diff --git a/drivers/virt/coco/arm-cca-guest/rsi-da.h b/drivers/virt/coco/arm-cca-guest/rsi-da.h
index 8a4d5f1b0263..f12430c7d792 100644
--- a/drivers/virt/coco/arm-cca-guest/rsi-da.h
+++ b/drivers/virt/coco/arm-cca-guest/rsi-da.h
@@ -10,9 +10,9 @@
 #include <linux/pci-tsm.h>
 #include <asm/rsi_smc.h>
 
-
 struct cca_guest_dsc {
 	struct pci_tsm_pf0 pci;
+	unsigned long instance_id;
 };
 
 static inline struct cca_guest_dsc *to_cca_guest_dsc(struct pci_dev *pdev)
@@ -24,4 +24,5 @@ static inline struct cca_guest_dsc *to_cca_guest_dsc(struct pci_dev *pdev)
 	return container_of(tsm, struct cca_guest_dsc, pci.tsm);
 }
 
+int rsi_device_lock(struct pci_dev *pdev);
 #endif
-- 
2.43.0