[PATCH v2 0/4] firmware: Add support for Qualcomm UEFI Secure Application

[PATCH v2 0/4] firmware: Add support for Qualcomm UEFI Secure Application

[Maximilian Luz]

This series adds basic support for the QSEECOM interface used to
communicate with secure applications running in the TrustZone on certain
Qualcomm devices. In addition to that, it also provides a driver for
"uefisecapp", the secure application managing access to UEFI variables
on such platforms.

For a more detailed description, see the blurb of v1, which can be found
at https://lore.kernel.org/lkml/20220723224949.1089973-1-luzmaximilian@gmail.com/.


This series depends on the following series:

 - "efi: efivars: drop kobject from efivars_register()"
   (https://lore.kernel.org/lkml/20230117124310.16594-1-johan+linaro@kernel.org/)

 - "efi: verify that variable services are supported"
   (https://lore.kernel.org/lkml/20230119164255.28091-1-johan+linaro@kernel.org/)

   with subsequent fix

   "efivarfs: fix NULL-deref on mount when no efivars"
   (https://lore.kernel.org/lkml/20230126112129.4602-1-johan+linaro@kernel.org/)

which have all been included in the "next" branch of

  https://git.kernel.org/pub/scm/linux/kernel/git/efi/efi.git


Changes in v2:

 - Bind the qseecom interface to a device.

 - Establish a device link between the new qseecom device and the SCM
   device to ensure proper PM and remove ordering.

 - Remove the compatible for uefisecapp. Instead, introduce a compatible
   for the qseecom device. This directly reflects ACPI tables and the
   QCOM0476 device described therein, which is responsible for the
   secure app / qseecom interface (i.e., the same purpose).

   Client devices representing apps handled by the kernel (such as
   uefisecapp) are now directly instantiated by the qseecom driver,
   based on the respective platform-specific compatible.

 - Rename the base name (qctree -> qseecom) to allow differentiation
   between old (qseecom) and new (smcinvoke) interfaces to the trusted
   execution environment. This directly reflects downstream naming by
   Qualcomm.


Maximilian Luz (4):
  firmware: qcom_scm: Export SCM call functions
  firmware: Add support for Qualcomm Secure Execution Environment SCM
    interface
  dt-bindings: firmware: Add Qualcomm QSEECOM interface
  firmware: Add support for Qualcomm UEFI Secure Application

 .../bindings/firmware/qcom,qseecom.yaml       |  49 ++
 MAINTAINERS                                   |  14 +
 drivers/firmware/Kconfig                      |  31 +
 drivers/firmware/Makefile                     |   2 +
 drivers/firmware/qcom_qseecom.c               | 323 ++++++++
 drivers/firmware/qcom_qseecom_uefisecapp.c    | 746 ++++++++++++++++++
 drivers/firmware/qcom_scm.c                   | 118 ++-
 drivers/firmware/qcom_scm.h                   |  47 --
 include/linux/qcom_qseecom.h                  | 190 +++++
 include/linux/qcom_scm.h                      |  49 ++
 10 files changed, 1483 insertions(+), 86 deletions(-)
 create mode 100644 Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
 create mode 100644 drivers/firmware/qcom_qseecom.c
 create mode 100644 drivers/firmware/qcom_qseecom_uefisecapp.c
 create mode 100644 include/linux/qcom_qseecom.h

-- 
2.39.0

[PATCH v2 1/4] firmware: qcom_scm: Export SCM call functions

[Maximilian Luz]

Make qcom_scm_call, qcom_scm_call_atomic and associated types accessible
to other modules.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
---

Changes in v2:
 - No functional changes

---
 drivers/firmware/qcom_scm.c | 118 ++++++++++++++++++++++++------------
 drivers/firmware/qcom_scm.h |  47 --------------
 include/linux/qcom_scm.h    |  49 +++++++++++++++
 3 files changed, 128 insertions(+), 86 deletions(-)

diff --git a/drivers/firmware/qcom_scm.c b/drivers/firmware/qcom_scm.c
index 2000323722bf..7305756d02b0 100644
--- a/drivers/firmware/qcom_scm.c
+++ b/drivers/firmware/qcom_scm.c
@@ -212,16 +212,17 @@ static enum qcom_scm_convention __get_convention(void)
 }
 
 /**
- * qcom_scm_call() - Invoke a syscall in the secure world
- * @dev:	device
+ * __qcom_scm_call() - Invoke a syscall in the secure world
+ * @dev:	Device. Depending on the command and number of arguments, this
+ *		is optional.
  * @desc:	Descriptor structure containing arguments and return values
  * @res:        Structure containing results from SMC/HVC call
  *
  * Sends a command to the SCM and waits for the command to finish processing.
  * This should *only* be called in pre-emptible context.
  */
-static int qcom_scm_call(struct device *dev, const struct qcom_scm_desc *desc,
-			 struct qcom_scm_res *res)
+static int __qcom_scm_call(struct device *dev, const struct qcom_scm_desc *desc,
+			   struct qcom_scm_res *res)
 {
 	might_sleep();
 	switch (__get_convention()) {
@@ -236,18 +237,39 @@ static int qcom_scm_call(struct device *dev, const struct qcom_scm_desc *desc,
 	}
 }
 
+/**
+ * qcom_scm_call() - Invoke a syscall in the secure world
+ * @desc:	Descriptor structure containing arguments and return values
+ * @res:        Structure containing results from SMC/HVC call
+ *
+ * Sends a command to the SCM and waits for the command to finish processing.
+ * This should *only* be called in pre-emptible context.
+ *
+ * Returns zero on success, -ENODEV if the SCM device has not been set up yet,
+ * or other non-zero status codes on failure.
+ */
+int qcom_scm_call(const struct qcom_scm_desc *desc, struct qcom_scm_res *res)
+{
+	if (!__scm)
+		return -ENODEV;
+
+	return __qcom_scm_call(__scm->dev, desc, res);
+}
+EXPORT_SYMBOL_GPL(qcom_scm_call);
+
 /**
  * qcom_scm_call_atomic() - atomic variation of qcom_scm_call()
- * @dev:	device
+ * @dev:	Device. Depending on the command and number of arguments, this
+ *		is optional.
  * @desc:	Descriptor structure containing arguments and return values
  * @res:	Structure containing results from SMC/HVC call
  *
  * Sends a command to the SCM and waits for the command to finish processing.
  * This can be called in atomic context.
  */
-static int qcom_scm_call_atomic(struct device *dev,
-				const struct qcom_scm_desc *desc,
-				struct qcom_scm_res *res)
+static int __qcom_scm_call_atomic(struct device *dev,
+				  const struct qcom_scm_desc *desc,
+				  struct qcom_scm_res *res)
 {
 	switch (__get_convention()) {
 	case SMC_CONVENTION_ARM_32:
@@ -261,6 +283,26 @@ static int qcom_scm_call_atomic(struct device *dev,
 	}
 }
 
+/**
+ * qcom_scm_call_atomic() - atomic variation of qcom_scm_call()
+ * @desc:	Descriptor structure containing arguments and return values
+ * @res:	Structure containing results from SMC/HVC call
+ *
+ * Sends a command to the SCM and waits for the command to finish processing.
+ * This can be called in atomic context.
+ *
+ * Returns zero on success, -ENODEV if the SCM device has not been set up yet,
+ * or other non-zero status codes on failure.
+ */
+int qcom_scm_call_atomic(const struct qcom_scm_desc *desc, struct qcom_scm_res *res)
+{
+	if (!__scm)
+		return -ENODEV;
+
+	return __qcom_scm_call_atomic(__scm->dev, desc, res);
+}
+EXPORT_SYMBOL_GPL(qcom_scm_call_atomic);
+
 static bool __qcom_scm_is_call_available(struct device *dev, u32 svc_id,
 					 u32 cmd_id)
 {
@@ -287,7 +329,7 @@ static bool __qcom_scm_is_call_available(struct device *dev, u32 svc_id,
 		return false;
 	}
 
-	ret = qcom_scm_call(dev, &desc, &res);
+	ret = __qcom_scm_call(dev, &desc, &res);
 
 	return ret ? false : !!res.result[0];
 }
@@ -312,7 +354,7 @@ static int qcom_scm_set_boot_addr(void *entry, const u8 *cpu_bits)
 	desc.args[0] = flags;
 	desc.args[1] = virt_to_phys(entry);
 
-	return qcom_scm_call_atomic(__scm ? __scm->dev : NULL, &desc, NULL);
+	return __qcom_scm_call_atomic(__scm ? __scm->dev : NULL, &desc, NULL);
 }
 
 static int qcom_scm_set_boot_addr_mc(void *entry, unsigned int flags)
@@ -334,7 +376,7 @@ static int qcom_scm_set_boot_addr_mc(void *entry, unsigned int flags)
 	if (!__scm || __get_convention() == SMC_CONVENTION_LEGACY)
 		return -EOPNOTSUPP;
 
-	return qcom_scm_call(__scm->dev, &desc, NULL);
+	return __qcom_scm_call(__scm->dev, &desc, NULL);
 }
 
 /**
@@ -384,7 +426,7 @@ void qcom_scm_cpu_power_down(u32 flags)
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
 
-	qcom_scm_call_atomic(__scm ? __scm->dev : NULL, &desc, NULL);
+	__qcom_scm_call_atomic(__scm ? __scm->dev : NULL, &desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_cpu_power_down);
 
@@ -401,7 +443,7 @@ int qcom_scm_set_remote_state(u32 state, u32 id)
 	struct qcom_scm_res res;
 	int ret;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call(&desc, &res);
 
 	return ret ? : res.result[0];
 }
@@ -419,7 +461,7 @@ static int __qcom_scm_set_dload_mode(struct device *dev, bool enable)
 
 	desc.args[1] = enable ? QCOM_SCM_BOOT_SET_DLOAD_MODE : 0;
 
-	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
+	return qcom_scm_call_atomic(&desc, NULL);
 }
 
 static void qcom_scm_set_download_mode(bool enable)
@@ -499,7 +541,7 @@ int qcom_scm_pas_init_image(u32 peripheral, const void *metadata, size_t size,
 
 	desc.args[1] = mdata_phys;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = __qcom_scm_call(__scm->dev, &desc, &res);
 
 	qcom_scm_bw_disable();
 	qcom_scm_clk_disable();
@@ -565,7 +607,7 @@ int qcom_scm_pas_mem_setup(u32 peripheral, phys_addr_t addr, phys_addr_t size)
 	if (ret)
 		return ret;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call(&desc, &res);
 	qcom_scm_bw_disable();
 	qcom_scm_clk_disable();
 
@@ -600,7 +642,7 @@ int qcom_scm_pas_auth_and_reset(u32 peripheral)
 	if (ret)
 		return ret;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call(&desc, &res);
 	qcom_scm_bw_disable();
 	qcom_scm_clk_disable();
 
@@ -634,7 +676,7 @@ int qcom_scm_pas_shutdown(u32 peripheral)
 	if (ret)
 		return ret;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call(&desc, &res);
 
 	qcom_scm_bw_disable();
 	qcom_scm_clk_disable();
@@ -666,7 +708,7 @@ bool qcom_scm_pas_supported(u32 peripheral)
 					  QCOM_SCM_PIL_PAS_IS_SUPPORTED))
 		return false;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = __qcom_scm_call(__scm->dev, &desc, &res);
 
 	return ret ? false : !!res.result[0];
 }
@@ -685,7 +727,7 @@ static int __qcom_scm_pas_mss_reset(struct device *dev, bool reset)
 	struct qcom_scm_res res;
 	int ret;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call(&desc, &res);
 
 	return ret ? : res.result[0];
 }
@@ -725,8 +767,7 @@ int qcom_scm_io_readl(phys_addr_t addr, unsigned int *val)
 	struct qcom_scm_res res;
 	int ret;
 
-
-	ret = qcom_scm_call_atomic(__scm->dev, &desc, &res);
+	ret = qcom_scm_call_atomic(&desc, &res);
 	if (ret >= 0)
 		*val = res.result[0];
 
@@ -745,7 +786,7 @@ int qcom_scm_io_writel(phys_addr_t addr, unsigned int val)
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
 
-	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
+	return qcom_scm_call_atomic(&desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_io_writel);
 
@@ -775,7 +816,7 @@ int qcom_scm_restore_sec_cfg(u32 device_id, u32 spare)
 	struct qcom_scm_res res;
 	int ret;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call(&desc, &res);
 
 	return ret ? : res.result[0];
 }
@@ -793,7 +834,7 @@ int qcom_scm_iommu_secure_ptbl_size(u32 spare, size_t *size)
 	struct qcom_scm_res res;
 	int ret;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call(&desc, &res);
 
 	if (size)
 		*size = res.result[0];
@@ -816,7 +857,7 @@ int qcom_scm_iommu_secure_ptbl_init(u64 addr, u32 size, u32 spare)
 	};
 	int ret;
 
-	ret = qcom_scm_call(__scm->dev, &desc, NULL);
+	ret = qcom_scm_call(&desc, NULL);
 
 	/* the pg table has been initialized already, ignore the error */
 	if (ret == -EPERM)
@@ -837,7 +878,7 @@ int qcom_scm_iommu_set_cp_pool_size(u32 spare, u32 size)
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
 
-	return qcom_scm_call(__scm->dev, &desc, NULL);
+	return qcom_scm_call(&desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_iommu_set_cp_pool_size);
 
@@ -859,7 +900,7 @@ int qcom_scm_mem_protect_video_var(u32 cp_start, u32 cp_size,
 	};
 	struct qcom_scm_res res;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call(&desc, &res);
 
 	return ret ? : res.result[0];
 }
@@ -887,7 +928,7 @@ static int __qcom_scm_assign_mem(struct device *dev, phys_addr_t mem_region,
 	};
 	struct qcom_scm_res res;
 
-	ret = qcom_scm_call(dev, &desc, &res);
+	ret = __qcom_scm_call(dev, &desc, &res);
 
 	return ret ? : res.result[0];
 }
@@ -1004,7 +1045,7 @@ int qcom_scm_ocmem_lock(enum qcom_scm_ocmem_client id, u32 offset, u32 size,
 		.arginfo = QCOM_SCM_ARGS(4),
 	};
 
-	return qcom_scm_call(__scm->dev, &desc, NULL);
+	return qcom_scm_call(&desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_ocmem_lock);
 
@@ -1027,7 +1068,7 @@ int qcom_scm_ocmem_unlock(enum qcom_scm_ocmem_client id, u32 offset, u32 size)
 		.arginfo = QCOM_SCM_ARGS(3),
 	};
 
-	return qcom_scm_call(__scm->dev, &desc, NULL);
+	return qcom_scm_call(&desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_ocmem_unlock);
 
@@ -1068,7 +1109,7 @@ int qcom_scm_ice_invalidate_key(u32 index)
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
 
-	return qcom_scm_call(__scm->dev, &desc, NULL);
+	return qcom_scm_call(&desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_ice_invalidate_key);
 
@@ -1129,7 +1170,7 @@ int qcom_scm_ice_set_key(u32 index, const u8 *key, u32 key_size,
 	memcpy(keybuf, key, key_size);
 	desc.args[1] = key_phys;
 
-	ret = qcom_scm_call(__scm->dev, &desc, NULL);
+	ret = qcom_scm_call(&desc, NULL);
 
 	memzero_explicit(keybuf, key_size);
 
@@ -1198,7 +1239,7 @@ int qcom_scm_hdcp_req(struct qcom_scm_hdcp_req *req, u32 req_cnt, u32 *resp)
 	if (ret)
 		return ret;
 
-	ret = qcom_scm_call(__scm->dev, &desc, &res);
+	ret = qcom_scm_call(&desc, &res);
 	*resp = res.result[0];
 
 	qcom_scm_clk_disable();
@@ -1219,7 +1260,7 @@ int qcom_scm_iommu_set_pt_format(u32 sec_id, u32 ctx_num, u32 pt_fmt)
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
 
-	return qcom_scm_call(__scm->dev, &desc, NULL);
+	return qcom_scm_call(&desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_iommu_set_pt_format);
 
@@ -1234,8 +1275,7 @@ int qcom_scm_qsmmu500_wait_safe_toggle(bool en)
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
 
-
-	return qcom_scm_call_atomic(__scm->dev, &desc, NULL);
+	return qcom_scm_call_atomic(&desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_qsmmu500_wait_safe_toggle);
 
@@ -1255,7 +1295,7 @@ int qcom_scm_lmh_profile_change(u32 profile_id)
 		.owner = ARM_SMCCC_OWNER_SIP,
 	};
 
-	return qcom_scm_call(__scm->dev, &desc, NULL);
+	return qcom_scm_call(&desc, NULL);
 }
 EXPORT_SYMBOL(qcom_scm_lmh_profile_change);
 
@@ -1290,7 +1330,7 @@ int qcom_scm_lmh_dcvsh(u32 payload_fn, u32 payload_reg, u32 payload_val,
 
 	desc.args[0] = payload_phys;
 
-	ret = qcom_scm_call(__scm->dev, &desc, NULL);
+	ret = __qcom_scm_call(__scm->dev, &desc, NULL);
 
 	dma_free_coherent(__scm->dev, payload_size, payload_buf, payload_phys);
 	return ret;
diff --git a/drivers/firmware/qcom_scm.h b/drivers/firmware/qcom_scm.h
index e6e512bd57d1..87eb726be7d0 100644
--- a/drivers/firmware/qcom_scm.h
+++ b/drivers/firmware/qcom_scm.h
@@ -13,53 +13,6 @@ enum qcom_scm_convention {
 
 extern enum qcom_scm_convention qcom_scm_convention;
 
-#define MAX_QCOM_SCM_ARGS 10
-#define MAX_QCOM_SCM_RETS 3
-
-enum qcom_scm_arg_types {
-	QCOM_SCM_VAL,
-	QCOM_SCM_RO,
-	QCOM_SCM_RW,
-	QCOM_SCM_BUFVAL,
-};
-
-#define QCOM_SCM_ARGS_IMPL(num, a, b, c, d, e, f, g, h, i, j, ...) (\
-			   (((a) & 0x3) << 4) | \
-			   (((b) & 0x3) << 6) | \
-			   (((c) & 0x3) << 8) | \
-			   (((d) & 0x3) << 10) | \
-			   (((e) & 0x3) << 12) | \
-			   (((f) & 0x3) << 14) | \
-			   (((g) & 0x3) << 16) | \
-			   (((h) & 0x3) << 18) | \
-			   (((i) & 0x3) << 20) | \
-			   (((j) & 0x3) << 22) | \
-			   ((num) & 0xf))
-
-#define QCOM_SCM_ARGS(...) QCOM_SCM_ARGS_IMPL(__VA_ARGS__, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
-
-
-/**
- * struct qcom_scm_desc
- * @arginfo:	Metadata describing the arguments in args[]
- * @args:	The array of arguments for the secure syscall
- */
-struct qcom_scm_desc {
-	u32 svc;
-	u32 cmd;
-	u32 arginfo;
-	u64 args[MAX_QCOM_SCM_ARGS];
-	u32 owner;
-};
-
-/**
- * struct qcom_scm_res
- * @result:	The values returned by the secure syscall
- */
-struct qcom_scm_res {
-	u64 result[MAX_QCOM_SCM_RETS];
-};
-
 int qcom_scm_wait_for_wq_completion(u32 wq_ctx);
 int scm_get_wq_ctx(u32 *wq_ctx, u32 *flags, u32 *more_pending);
 
diff --git a/include/linux/qcom_scm.h b/include/linux/qcom_scm.h
index 1e449a5d7f5c..162746467c22 100644
--- a/include/linux/qcom_scm.h
+++ b/include/linux/qcom_scm.h
@@ -11,6 +11,55 @@
 
 #include <dt-bindings/firmware/qcom,scm.h>
 
+#define QCOM_SCM_ARGS_IMPL(num, a, b, c, d, e, f, g, h, i, j, ...) (\
+			   (((a) & 0x3) << 4) | \
+			   (((b) & 0x3) << 6) | \
+			   (((c) & 0x3) << 8) | \
+			   (((d) & 0x3) << 10) | \
+			   (((e) & 0x3) << 12) | \
+			   (((f) & 0x3) << 14) | \
+			   (((g) & 0x3) << 16) | \
+			   (((h) & 0x3) << 18) | \
+			   (((i) & 0x3) << 20) | \
+			   (((j) & 0x3) << 22) | \
+			   ((num) & 0xf))
+
+#define QCOM_SCM_ARGS(...) QCOM_SCM_ARGS_IMPL(__VA_ARGS__, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0)
+
+#define MAX_QCOM_SCM_ARGS 10
+#define MAX_QCOM_SCM_RETS 3
+
+enum qcom_scm_arg_types {
+	QCOM_SCM_VAL,
+	QCOM_SCM_RO,
+	QCOM_SCM_RW,
+	QCOM_SCM_BUFVAL,
+};
+
+/**
+ * struct qcom_scm_desc - SCM call descriptor.
+ * @arginfo:	Metadata describing the arguments in args[]
+ * @args:	The array of arguments for the secure syscall
+ */
+struct qcom_scm_desc {
+	u32 svc;
+	u32 cmd;
+	u32 arginfo;
+	u64 args[MAX_QCOM_SCM_ARGS];
+	u32 owner;
+};
+
+/**
+ * struct qcom_scm_res - SCM call response.
+ * @result:	The values returned by the secure syscall
+ */
+struct qcom_scm_res {
+	u64 result[MAX_QCOM_SCM_RETS];
+};
+
+int qcom_scm_call(const struct qcom_scm_desc *desc, struct qcom_scm_res *res);
+int qcom_scm_call_atomic(const struct qcom_scm_desc *desc, struct qcom_scm_res *res);
+
 #define QCOM_SCM_VERSION(major, minor)	(((major) << 16) | ((minor) & 0xFF))
 #define QCOM_SCM_CPU_PWR_DOWN_L2_ON	0x0
 #define QCOM_SCM_CPU_PWR_DOWN_L2_OFF	0x1
-- 
2.39.0

[PATCH v2 2/4] firmware: Add support for Qualcomm Secure Execution Environment SCM interface

[Maximilian Luz]

Add support for SCM calls to Secure OS and the Secure Execution
Environment (SEE) residing in the TrustZone (TZ) via the QSEECOM
interface. This allows communication with Secure/TZ applications, for
example 'uefisecapp' managing access to UEFI variables.

The interface is managed by a platform device to ensure correct lifetime
and establish a device link to the Qualcomm SCM device.

While this patch introduces only a very basic interface without the more
advanced features (such as re-entrant and blocking SCM calls and
listeners/callbacks), this is enough to talk to the aforementioned
'uefisecapp'.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
---

Changes in v2:
 - Bind the interface to a device.
 - Establish a device link to the SCM device to ensure proper ordering.
 - Register client apps as child devices instead of requiring them to be
   specified in the device tree.
 - Rename (qctree -> qseecom) to allow differentiation between old
   (qseecom) and new (smcinvoke) interfaces to the trusted execution
   environment.

---
 MAINTAINERS                     |   7 +
 drivers/firmware/Kconfig        |  15 ++
 drivers/firmware/Makefile       |   1 +
 drivers/firmware/qcom_qseecom.c | 314 ++++++++++++++++++++++++++++++++
 include/linux/qcom_qseecom.h    | 190 +++++++++++++++++++
 5 files changed, 527 insertions(+)
 create mode 100644 drivers/firmware/qcom_qseecom.c
 create mode 100644 include/linux/qcom_qseecom.h

diff --git a/MAINTAINERS b/MAINTAINERS
index f2c3d471fe8f..846d6c927840 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17387,6 +17387,13 @@ F:	Documentation/networking/device_drivers/cellular/qualcomm/rmnet.rst
 F:	drivers/net/ethernet/qualcomm/rmnet/
 F:	include/linux/if_rmnet.h
 
+QUALCOMM SECURE EXECUTION ENVIRONMENT COMMUNICATION DRIVER
+M:	Maximilian Luz <luzmaximilian@gmail.com>
+L:	linux-arm-msm@vger.kernel.org
+S:	Maintained
+F:	drivers/firmware/qcom_qseecom.c
+F:	include/linux/qcom_qseecom.h
+
 QUALCOMM TSENS THERMAL DRIVER
 M:	Amit Kucheria <amitk@kernel.org>
 M:	Thara Gopinath <thara.gopinath@gmail.com>
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index b59e3041fd62..22eec0835abf 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -226,6 +226,21 @@ config QCOM_SCM_DOWNLOAD_MODE_DEFAULT
 
 	  Say Y here to enable "download mode" by default.
 
+config QCOM_QSEECOM
+	tristate "Qualcomm QSEECOM interface driver"
+	select MFD_CORE
+	select QCOM_SCM
+	help
+	  Various Qualcomm SoCs have a Secure Execution Environment (SEE) running
+	  in the Trust Zone. This module provides an interface to that via the
+	  QSEECOM mechanism, using SCM calls.
+
+	  The QSEECOM interface allows, among other things, access to applications
+	  running in the SEE. An example of such an application is 'uefisecapp',
+	  which is required to access UEFI variables on certain systems.
+
+	  Select M or Y here to enable the QSEECOM interface driver.
+
 config SYSFB
 	bool
 	select BOOT_VESA_SUPPORT
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index 28fcddcd688f..aa48e0821b7d 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -20,6 +20,7 @@ obj-$(CONFIG_RASPBERRYPI_FIRMWARE) += raspberrypi.o
 obj-$(CONFIG_FW_CFG_SYSFS)	+= qemu_fw_cfg.o
 obj-$(CONFIG_QCOM_SCM)		+= qcom-scm.o
 qcom-scm-objs += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
+obj-$(CONFIG_QCOM_QSEECOM)	+= qcom_qseecom.o
 obj-$(CONFIG_SYSFB)		+= sysfb.o
 obj-$(CONFIG_SYSFB_SIMPLEFB)	+= sysfb_simplefb.o
 obj-$(CONFIG_TI_SCI_PROTOCOL)	+= ti_sci.o
diff --git a/drivers/firmware/qcom_qseecom.c b/drivers/firmware/qcom_qseecom.c
new file mode 100644
index 000000000000..2553742ccc43
--- /dev/null
+++ b/drivers/firmware/qcom_qseecom.c
@@ -0,0 +1,314 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Interface driver for the Qualcomm Secure Execution Environment (SEE) /
+ * TrustZone OS (TzOS). Manages communication via the QSEECOM interface, using
+ * Secure Channel Manager (SCM) calls.
+ *
+ * Copyright (C) 2023 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#include <asm/barrier.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/mfd/core.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/of_platform.h>
+#include <linux/platform_device.h>
+#include <linux/qcom_scm.h>
+#include <linux/string.h>
+
+#include <linux/qcom_qseecom.h>
+
+
+/* -- Secure-OS SCM call interface. ----------------------------------------- */
+
+static int __qseecom_scm_call(const struct qcom_scm_desc *desc,
+			      struct qseecom_scm_resp *res)
+{
+	struct qcom_scm_res scm_res = {};
+	int status;
+
+	status = qcom_scm_call(desc, &scm_res);
+
+	res->status = scm_res.result[0];
+	res->resp_type = scm_res.result[1];
+	res->data = scm_res.result[2];
+
+	if (status)
+		return status;
+
+	return 0;
+}
+
+/**
+ * qseecom_scm_call() - Perform a QSEECOM SCM call.
+ * @qsee: The QSEECOM device.
+ * @desc: SCM call descriptor.
+ * @res:  SCM call response (output).
+ *
+ * Performs the QSEECOM SCM call described by @desc, returning the response in
+ * @rsp.
+ *
+ * Return: Returns zero on success, nonzero on failure.
+ */
+int qseecom_scm_call(struct qseecom_device *qsee, const struct qcom_scm_desc *desc,
+		     struct qseecom_scm_resp *res)
+{
+	int status;
+
+	/*
+	 * Note: Multiple QSEECOM SCM calls should not be executed same time,
+	 * so lock things here. This needs to be extended to callback/listener
+	 * handling when support for that is implemented.
+	 */
+
+	mutex_lock(&qsee->scm_call_lock);
+	status = __qseecom_scm_call(desc, res);
+	mutex_unlock(&qsee->scm_call_lock);
+
+	dev_dbg(qsee->dev, "%s: owner=%x, svc=%x, cmd=%x, status=%lld, type=%llx, data=%llx",
+		__func__, desc->owner, desc->svc, desc->cmd, res->status,
+		res->resp_type, res->data);
+
+	if (status) {
+		dev_err(qsee->dev, "qcom_scm_call failed with error %d\n", status);
+		return status;
+	}
+
+	/*
+	 * TODO: Handle incomplete and blocked calls:
+	 *
+	 * Incomplete and blocked calls are not supported yet. Some devices
+	 * and/or commands require those, some don't. Let's warn about them
+	 * prominently in case someone attempts to try these commands with a
+	 * device/command combination that isn't supported yet.
+	 */
+	WARN_ON(res->status == QSEECOM_RESULT_INCOMPLETE);
+	WARN_ON(res->status == QSEECOM_RESULT_BLOCKED_ON_LISTENER);
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qseecom_scm_call);
+
+
+/* -- Secure App interface. ------------------------------------------------- */
+
+/**
+ * qseecom_app_get_id() - Query the app ID for a given SEE app name.
+ * @qsee:     The QSEECOM device.
+ * @app_name: The name of the app.
+ * @app_id:   The returned app ID.
+ *
+ * Query and return the application ID of the SEE app identified by the given
+ * name. This returned ID is the unique identifier of the app required for
+ * subsequent communication.
+ *
+ * Return: Returns zero on success, nonzero on failure. Returns -ENOENT if the
+ * app has not been loaded or could not be found.
+ */
+int qseecom_app_get_id(struct qseecom_device *qsee, const char *app_name, u32 *app_id)
+{
+	unsigned long name_buf_size = QSEECOM_MAX_APP_NAME_SIZE;
+	unsigned long app_name_len = strlen(app_name);
+	struct qcom_scm_desc desc = {};
+	struct qseecom_scm_resp res = {};
+	dma_addr_t name_buf_phys;
+	char *name_buf;
+	int status;
+
+	if (app_name_len >= name_buf_size)
+		return -EINVAL;
+
+	name_buf = kzalloc(name_buf_size, GFP_KERNEL);
+	if (!name_buf)
+		return -ENOMEM;
+
+	memcpy(name_buf, app_name, app_name_len);
+
+	name_buf_phys = dma_map_single(qsee->dev, name_buf, name_buf_size, DMA_TO_DEVICE);
+	if (dma_mapping_error(qsee->dev, name_buf_phys)) {
+		kfree(name_buf);
+		dev_err(qsee->dev, "failed to map dma address\n");
+		return -EFAULT;
+	}
+
+	desc.owner = QSEECOM_TZ_OWNER_QSEE_OS;
+	desc.svc = QSEECOM_TZ_SVC_APP_MGR;
+	desc.cmd = 0x03;
+	desc.arginfo = QCOM_SCM_ARGS(2, QCOM_SCM_RW, QCOM_SCM_VAL);
+	desc.args[0] = name_buf_phys;
+	desc.args[1] = app_name_len;
+
+	status = qseecom_scm_call(qsee, &desc, &res);
+	dma_unmap_single(qsee->dev, name_buf_phys, name_buf_size, DMA_TO_DEVICE);
+	kfree(name_buf);
+
+	if (status)
+		return status;
+
+	if (res.status != QSEECOM_RESULT_SUCCESS)
+		return -ENOENT;
+
+	*app_id = res.data;
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qseecom_app_get_id);
+
+/**
+ * qseecom_app_send() - Send to and receive data from a given SEE app.
+ * @qsee:   The QSEECOM device.
+ * @app_id: The ID of the app to communicate with.
+ * @req:    DMA region of the request sent to the app.
+ * @rsp:    DMA region of the response returned by the app.
+ *
+ * Sends a request to the SEE app identified by the given ID and read back its
+ * response. The caller must provide two DMA memory regions, one for the
+ * request and one for the response, and fill out the @req region with the
+ * respective (app-specific) request data. The SEE app reads this and returns
+ * its response in the @rsp region.
+ *
+ * Return: Returns zero on success, nonzero on failure.
+ */
+int qseecom_app_send(struct qseecom_device *qsee, u32 app_id, struct qseecom_dma *req,
+		     struct qseecom_dma *rsp)
+{
+	struct qseecom_scm_resp res = {};
+	int status;
+
+	struct qcom_scm_desc desc = {
+		.owner = QSEECOM_TZ_OWNER_TZ_APPS,
+		.svc = QSEECOM_TZ_SVC_APP_ID_PLACEHOLDER,
+		.cmd = 0x01,
+		.arginfo = QCOM_SCM_ARGS(5, QCOM_SCM_VAL,
+					 QCOM_SCM_RW, QCOM_SCM_VAL,
+					 QCOM_SCM_RW, QCOM_SCM_VAL),
+		.args[0] = app_id,
+		.args[1] = req->phys,
+		.args[2] = req->size,
+		.args[3] = rsp->phys,
+		.args[4] = rsp->size,
+	};
+
+	/* Make sure the request is fully written before sending it off. */
+	dma_wmb();
+
+	status = qseecom_scm_call(qsee, &desc, &res);
+
+	/* Make sure we don't attempt any reads before the SCM call is done. */
+	dma_rmb();
+
+	if (status)
+		return status;
+
+	if (res.status != QSEECOM_RESULT_SUCCESS)
+		return -EIO;
+
+	return 0;
+}
+EXPORT_SYMBOL_GPL(qseecom_app_send);
+
+
+/* -- Platform specific data. ----------------------------------------------- */
+
+struct qseecom_data {
+	const struct mfd_cell *cells;
+	int num_cells;
+};
+
+static const struct of_device_id qseecom_dt_match[] = {
+	{ .compatible = "qcom,qseecom-sc8280xp", },
+	{ .compatible = "qcom,qseecom", },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, qseecom_dt_match);
+
+
+/* -- Driver setup. --------------------------------------------------------- */
+
+static int qseecom_setup_scm_link(struct platform_device *pdev)
+{
+	const u32 flags = DL_FLAG_PM_RUNTIME | DL_FLAG_AUTOREMOVE_CONSUMER;
+	struct platform_device *scm_dev;
+	struct device_node *scm_node;
+	struct device_link *link;
+	int status = 0;
+
+	if (!pdev->dev.of_node)
+		return -ENODEV;
+
+	/* Find the SCM device. */
+	scm_node = of_parse_phandle(pdev->dev.of_node, "qcom,scm", 0);
+	if (!scm_node)
+		return -ENOENT;
+
+	scm_dev = of_find_device_by_node(scm_node);
+	if (!scm_dev) {
+		status = -ENODEV;
+		goto put;
+	}
+
+	/* Establish the device link. */
+	link = device_link_add(&pdev->dev, &scm_dev->dev, flags);
+	if (!link) {
+		status = -EINVAL;
+		goto put;
+	}
+
+	/* Make sure SCM has a driver bound, otherwise defer probe. */
+	if (link->supplier->links.status != DL_DEV_DRIVER_BOUND) {
+		status = -EPROBE_DEFER;
+		goto put;
+	}
+
+put:
+	of_node_put(scm_node);
+	return status;
+}
+
+static int qseecom_probe(struct platform_device *pdev)
+{
+	const struct qseecom_data *data;
+	struct qseecom_device *qsee;
+	int status;
+
+	/* Get platform data. */
+	data = of_device_get_match_data(&pdev->dev);
+
+	/* Set up device link. */
+	status = qseecom_setup_scm_link(pdev);
+	if (status)
+		return status;
+
+	/* Set up QSEECOM device. */
+	qsee = devm_kzalloc(&pdev->dev, sizeof(*qsee), GFP_KERNEL);
+	if (!qsee)
+		return -ENOMEM;
+
+	qsee->dev = &pdev->dev;
+	mutex_init(&qsee->scm_call_lock);
+
+	platform_set_drvdata(pdev, qsee);
+
+	/* Add child devices. */
+	if (data) {
+		status = devm_mfd_add_devices(&pdev->dev, PLATFORM_DEVID_NONE, data->cells,
+					      data->num_cells, NULL, 0, NULL);
+	}
+
+	return status;
+}
+
+static struct platform_driver qseecom_driver = {
+	.probe = qseecom_probe,
+	.driver = {
+		.name = "qcom_qseecom",
+		.of_match_table = qseecom_dt_match,
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+module_platform_driver(qseecom_driver);
+
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("Driver for Qualcomm QSEECOM secure OS and secure application interface");
+MODULE_LICENSE("GPL");
diff --git a/include/linux/qcom_qseecom.h b/include/linux/qcom_qseecom.h
new file mode 100644
index 000000000000..4bee5e551d6e
--- /dev/null
+++ b/include/linux/qcom_qseecom.h
@@ -0,0 +1,190 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Interface driver for the Qualcomm Secure Execution Environment (SEE) /
+ * TrustZone OS (TzOS). Manages communication via the QSEECOM interface, using
+ * Secure Channel Manager (SCM) calls.
+ *
+ * Copyright (C) 2023 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#ifndef _LINUX_QCOM_QSEECOM_H
+#define _LINUX_QCOM_QSEECOM_H
+
+#include <linux/device.h>
+#include <linux/dma-mapping.h>
+#include <linux/kernel.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/qcom_scm.h>
+#include <linux/types.h>
+
+
+/* -- DMA helpers. ---------------------------------------------------------- */
+
+/* DMA requirements for QSEECOM SCM calls. */
+#define QSEECOM_DMA_ALIGNMENT		8
+#define QSEECOM_DMA_ALIGN(ptr)		ALIGN(ptr, QSEECOM_DMA_ALIGNMENT)
+
+/**
+ * struct qseecom_dma - DMA memory region.
+ * @size: Size of the memory region, in bytes.
+ * @virt: Pointer / virtual address to the memory, accessible by the kernel.
+ * @phys: Physical address of the memory region.
+ */
+struct qseecom_dma {
+	unsigned long size;
+	void *virt;
+	dma_addr_t phys;
+};
+
+/**
+ * qseecom_dma_alloc() - Allocate a DMA-able memory region suitable for QSEECOM
+ * SCM calls.
+ * @dev:  The device used for DMA memory allocation.
+ * @dma:  Where to write the allocated memory addresses and size to.
+ * @size: Minimum size of the memory to be allocated.
+ * @gfp:  Flags used for allocation.
+ *
+ * Allocate a DMA-able memory region suitable for interaction with SEE
+ * services/applications and the TzOS. The provided size is treated as the
+ * minimum required size and rounded up, if necessary. The actually allocated
+ * memory region will be stored in @dma. Allocated memory must be freed via
+ * qseecom_dma_free().
+ *
+ * Return: Returns zero on success, -ENOMEM on allocation failure.
+ */
+static inline int qseecom_dma_alloc(struct device *dev, struct qseecom_dma *dma,
+				    unsigned long size, gfp_t gfp)
+{
+	size = PAGE_ALIGN(size);
+
+	dma->virt = dma_alloc_coherent(dev, size, &dma->phys, GFP_KERNEL);
+	if (!dma->virt)
+		return -ENOMEM;
+
+	dma->size = size;
+	return 0;
+}
+
+/**
+ * qseecom_dma_free() - Free a DMA memory region.
+ * @dev: The device used for allocation.
+ * @dma: The DMA region to be freed.
+ *
+ * Free a DMA region previously allocated via qseecom_dma_alloc(). Note that
+ * freeing sub-regions is not supported.
+ */
+static inline void qseecom_dma_free(struct device *dev, struct qseecom_dma *dma)
+{
+	dma_free_coherent(dev, dma->size, dma->virt, dma->phys);
+}
+
+/**
+ * qseecom_dma_realloc() - Re-allocate DMA memory region with the requested size.
+ * @dev:  The device used for allocation.
+ * @dma:  The region descriptor to be updated.
+ * @size: The new requested size.
+ * @gfp:  Flags used for allocation.
+ *
+ * Re-allocates a DMA memory region suitable for QSEECOM SCM calls to fit the
+ * requested amount of bytes, if necessary. Does nothing if the provided region
+ * already has enough space to store the requested data.
+ *
+ * See qseecom_dma_alloc() for details.
+ *
+ * Return: Returns zero on success, -ENOMEM on allocation failure.
+ */
+static inline int qseecom_dma_realloc(struct device *dev, struct qseecom_dma *dma,
+				      unsigned long size, gfp_t gfp)
+{
+	if (PAGE_ALIGN(size) <= dma->size)
+		return 0;
+
+	qseecom_dma_free(dev, dma);
+	return qseecom_dma_alloc(dev, dma, size, gfp);
+}
+
+/**
+ * qseecom_dma_aligned() - Create a aligned DMA memory sub-region suitable for
+ * QSEECOM SCM calls.
+ * @base:   Base DMA memory region, in which the new region will reside.
+ * @out:    Descriptor to store the aligned sub-region in.
+ * @offset: The offset inside base region at which to place the new sub-region.
+ *
+ * Creates an aligned DMA memory region suitable for QSEECOM SCM calls at or
+ * after the given offset. The size of the sub-region will be set to the
+ * remaining size in the base region after alignment, i.e., the end of the
+ * sub-region will be equal the end of the base region.
+ *
+ * Return: Returns zero on success or -EINVAL if the new aligned memory address
+ * would point outside the base region.
+ */
+static inline int qseecom_dma_aligned(const struct qseecom_dma *base, struct qseecom_dma *out,
+				      unsigned long offset)
+{
+	void *aligned = (void *)QSEECOM_DMA_ALIGN((uintptr_t)base->virt + offset);
+
+	if (aligned - base->virt > base->size)
+		return -EINVAL;
+
+	out->virt = aligned;
+	out->phys = base->phys + (out->virt - base->virt);
+	out->size = base->size - (out->virt - base->virt);
+
+	return 0;
+}
+
+
+/* -- Common interface. ----------------------------------------------------- */
+
+struct qseecom_device {
+	struct device *dev;
+	struct mutex scm_call_lock;	/* Guards QSEECOM SCM calls. */
+};
+
+
+/* -- Secure-OS SCM call interface. ----------------------------------------- */
+
+#define QSEECOM_TZ_OWNER_TZ_APPS		48
+#define QSEECOM_TZ_OWNER_QSEE_OS		50
+
+#define QSEECOM_TZ_SVC_APP_ID_PLACEHOLDER	0
+#define QSEECOM_TZ_SVC_APP_MGR			1
+
+enum qseecom_scm_result {
+	QSEECOM_RESULT_SUCCESS			= 0,
+	QSEECOM_RESULT_INCOMPLETE		= 1,
+	QSEECOM_RESULT_BLOCKED_ON_LISTENER	= 2,
+	QSEECOM_RESULT_FAILURE			= 0xFFFFFFFF,
+};
+
+enum qseecom_scm_resp_type {
+	QSEECOM_SCM_RES_APP_ID			= 0xEE01,
+	QSEECOM_SCM_RES_QSEOS_LISTENER_ID	= 0xEE02,
+};
+
+/**
+ * struct qseecom_scm_resp - QSEECOM SCM call response.
+ * @status:    Status of the SCM call. See &enum qseecom_scm_result.
+ * @resp_type: Type of the response. See &enum qseecom_scm_resp_type.
+ * @data:      Response data. The type of this data is given in @resp_type.
+ */
+struct qseecom_scm_resp {
+	u64 status;
+	u64 resp_type;
+	u64 data;
+};
+
+int qseecom_scm_call(struct qseecom_device *qsee, const struct qcom_scm_desc *desc,
+		     struct qseecom_scm_resp *res);
+
+
+/* -- Secure App interface. ------------------------------------------------- */
+
+#define QSEECOM_MAX_APP_NAME_SIZE			64
+
+int qseecom_app_get_id(struct qseecom_device *qsee, const char *app_name, u32 *app_id);
+int qseecom_app_send(struct qseecom_device *qsee, u32 app_id, struct qseecom_dma *req,
+		     struct qseecom_dma *rsp);
+
+#endif /* _LINUX_QCOM_QSEECOM_H */
-- 
2.39.0

[PATCH v2 3/4] dt-bindings: firmware: Add Qualcomm QSEECOM interface

[Maximilian Luz]

Add bindings for the Qualcomm Secure Execution Environment interface
(QSEECOM).

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
---

Changes in v2:
 - Replaces uefisecapp bindings.
 - Fix various dt-checker complaints.

---
 .../bindings/firmware/qcom,qseecom.yaml       | 49 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 50 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml

diff --git a/Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml b/Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
new file mode 100644
index 000000000000..540a604f81bc
--- /dev/null
+++ b/Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
@@ -0,0 +1,49 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/firmware/qcom,qseecom.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Qualcomm Secure Execution Environment Communication Interface
+
+maintainers:
+  - Maximilian Luz <luzmaximilian@gmail.com>
+
+description: |
+  QSEECOM provides an interface to Qualcomm's Secure Execution Environment
+  (SEE) running in the Trust Zone via SCM calls. In particular, it allows
+  communication with secure applications running therein.
+
+  Applications running in this environment can, for example, include
+  'uefisecapp', which is required for accessing UEFI variables on certain
+  systems as these cannot be accessed directly.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - qcom,qseecom-sc8280xp
+      - const: qcom,qseecom
+
+  qcom,scm:
+    $ref: '/schemas/types.yaml#/definitions/phandle'
+    description:
+      A phandle pointing to the QCOM SCM device (see ./qcom,scm.yaml).
+
+required:
+  - compatible
+  - qcom,scm
+
+additionalProperties: false
+
+examples:
+  - |
+    firmware {
+        scm {
+            compatible = "qcom,scm-sc8280xp", "qcom,scm";
+        };
+        qseecom {
+            compatible = "qcom,qseecom-sc8280xp", "qcom,qseecom";
+            qcom,scm = <&scm>;
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 846d6c927840..5493bcc5792c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17391,6 +17391,7 @@ QUALCOMM SECURE EXECUTION ENVIRONMENT COMMUNICATION DRIVER
 M:	Maximilian Luz <luzmaximilian@gmail.com>
 L:	linux-arm-msm@vger.kernel.org
 S:	Maintained
+F:	Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
 F:	drivers/firmware/qcom_qseecom.c
 F:	include/linux/qcom_qseecom.h
 
-- 
2.39.0

[PATCH v2 4/4] firmware: Add support for Qualcomm UEFI Secure Application

[Maximilian Luz]

On platforms using the Qualcomm UEFI Secure Application (uefisecapp),
EFI variables cannot be accessed via the standard interface in EFI
runtime mode. The respective functions return EFI_UNSUPPORTED. On these
platforms, we instead need to talk to uefisecapp. This commit provides
support for this and registers the respective efivars operations to
access EFI variables from the kernel.

Communication with uefisecapp follows the Qualcomm QSEECOM / Secure OS
conventions via the respective SCM call interface. This is also the
reason why variable access works normally while boot services are
active. During this time, said SCM interface is managed by the boot
services. When calling ExitBootServices(), the ownership is transferred
to the kernel. Therefore, UEFI must not use that interface itself (as
multiple parties accessing this interface at the same time may lead to
complications) and cannot access variables for us.

Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
---

Changes in v2:
 - Rename (qctree -> qseecom) to allow differentiation between old
   (qseecom) and new (smcinvoke) interfaces to the trusted execution
   environment.

---
 MAINTAINERS                                |   6 +
 drivers/firmware/Kconfig                   |  16 +
 drivers/firmware/Makefile                  |   1 +
 drivers/firmware/qcom_qseecom.c            |  11 +-
 drivers/firmware/qcom_qseecom_uefisecapp.c | 746 +++++++++++++++++++++
 5 files changed, 779 insertions(+), 1 deletion(-)
 create mode 100644 drivers/firmware/qcom_qseecom_uefisecapp.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 5493bcc5792c..51e4fb9a65f7 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -17378,6 +17378,12 @@ S:	Maintained
 F:	Documentation/devicetree/bindings/mtd/qcom,nandc.yaml
 F:	drivers/mtd/nand/raw/qcom_nandc.c
 
+QUALCOMM QSEECOM UEFISECAPP DRIVER
+M:	Maximilian Luz <luzmaximilian@gmail.com>
+L:	linux-arm-msm@vger.kernel.org
+S:	Maintained
+F:	drivers/firmware/qcom_qseecom_uefisecapp.c
+
 QUALCOMM RMNET DRIVER
 M:	Subash Abhinov Kasiviswanathan <quic_subashab@quicinc.com>
 M:	Sean Tranchetti <quic_stranche@quicinc.com>
diff --git a/drivers/firmware/Kconfig b/drivers/firmware/Kconfig
index 22eec0835abf..b9ad753a195b 100644
--- a/drivers/firmware/Kconfig
+++ b/drivers/firmware/Kconfig
@@ -241,6 +241,22 @@ config QCOM_QSEECOM
 
 	  Select M or Y here to enable the QSEECOM interface driver.
 
+config QCOM_QSEECOM_UEFISECAPP
+	tristate "Qualcomm SEE UEFI Secure App client driver"
+	depends on QCOM_QSEECOM
+	depends on EFI
+	help
+	  Various Qualcomm SoCs do not allow direct access to EFI variables.
+	  Instead, these need to be accessed via the UEFI Secure Application
+	  (uefisecapp), residing in the Secure Execution Environment (SEE).
+
+	  This module provides a client driver for uefisecapp, installing efivar
+	  operations to allow the kernel accessing EFI variables, and via that also
+	  provide user-space with access to EFI variables via efivarfs.
+
+	  Select M or Y here to provide access to EFI variables on the
+	  aforementioned platforms.
+
 config SYSFB
 	bool
 	select BOOT_VESA_SUPPORT
diff --git a/drivers/firmware/Makefile b/drivers/firmware/Makefile
index aa48e0821b7d..d41b094a5e58 100644
--- a/drivers/firmware/Makefile
+++ b/drivers/firmware/Makefile
@@ -21,6 +21,7 @@ obj-$(CONFIG_FW_CFG_SYSFS)	+= qemu_fw_cfg.o
 obj-$(CONFIG_QCOM_SCM)		+= qcom-scm.o
 qcom-scm-objs += qcom_scm.o qcom_scm-smc.o qcom_scm-legacy.o
 obj-$(CONFIG_QCOM_QSEECOM)	+= qcom_qseecom.o
+obj-$(CONFIG_QCOM_QSEECOM_UEFISECAPP) += qcom_qseecom_uefisecapp.o
 obj-$(CONFIG_SYSFB)		+= sysfb.o
 obj-$(CONFIG_SYSFB_SIMPLEFB)	+= sysfb_simplefb.o
 obj-$(CONFIG_TI_SCI_PROTOCOL)	+= ti_sci.o
diff --git a/drivers/firmware/qcom_qseecom.c b/drivers/firmware/qcom_qseecom.c
index 2553742ccc43..a57540199cd6 100644
--- a/drivers/firmware/qcom_qseecom.c
+++ b/drivers/firmware/qcom_qseecom.c
@@ -216,8 +216,17 @@ struct qseecom_data {
 	int num_cells;
 };
 
+static const struct mfd_cell qseecom_cells_sc8280xp[] = {
+	{ .name = "qcom_qseecom_uefisecapp", },
+};
+
+static const struct qseecom_data qseecom_data_sc8280xp = {
+	.cells = qseecom_cells_sc8280xp,
+	.num_cells = ARRAY_SIZE(qseecom_cells_sc8280xp),
+};
+
 static const struct of_device_id qseecom_dt_match[] = {
-	{ .compatible = "qcom,qseecom-sc8280xp", },
+	{ .compatible = "qcom,qseecom-sc8280xp", .data = &qseecom_data_sc8280xp },
 	{ .compatible = "qcom,qseecom", },
 	{ }
 };
diff --git a/drivers/firmware/qcom_qseecom_uefisecapp.c b/drivers/firmware/qcom_qseecom_uefisecapp.c
new file mode 100644
index 000000000000..3e9955639acc
--- /dev/null
+++ b/drivers/firmware/qcom_qseecom_uefisecapp.c
@@ -0,0 +1,746 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Client driver for Qualcomm UEFI Secure Application (qcom.tz.uefisecapp).
+ * Provides access to UEFI variables on platforms where they are secured by the
+ * aforementioned Secure Execution Environment (SEE) application.
+ *
+ * Copyright (C) 2023 Maximilian Luz <luzmaximilian@gmail.com>
+ */
+
+#include <linux/efi.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/qcom_qseecom.h>
+#include <linux/slab.h>
+#include <linux/types.h>
+
+
+/* -- UTF-16 helpers. ------------------------------------------------------- */
+
+static unsigned long utf16_strnlen(const efi_char16_t *str, unsigned long max)
+{
+	size_t i;
+
+	for (i = 0; *str != 0 && i < max; i++, str++) {
+		/* Do nothing, all is handled in the for statement. */
+	}
+
+	return i;
+}
+
+/**
+ * utf16_strsize() - Compute the number of bytes required to store a
+ * null-terminated UTF-16 string.
+ * @str: The string to compute the size for.
+ *
+ * Return: Returns the minimum number of bytes required to store the given
+ * null-terminated string, including its null-terminator.
+ */
+static unsigned long utf16_strsize(const efi_char16_t *str)
+{
+	return (utf16_strnlen(str, U32_MAX) + 1) * sizeof(str[0]);
+}
+
+static unsigned long utf16_strlcpy(efi_char16_t *dst, const efi_char16_t *src, unsigned long size)
+{
+	unsigned long actual = utf16_strnlen(src, size - 1);
+
+	memcpy(dst, src, actual * sizeof(src[0]));
+	dst[actual] = 0;
+
+	return actual;
+}
+
+/**
+ * utf16_copy_to_buf() - Copy the given UTF-16 string to a buffer.
+ * @dst:   Pointer to the output buffer
+ * @src:   Pointer to the null-terminated UTF-16 string to be copied.
+ * @bytes: Maximum number of bytes to copy.
+ *
+ * Copies the given string to the given buffer, ensuring that the output buffer
+ * is not overrun and that the string in the output buffer will always be
+ * null-terminated.
+ *
+ * Return: Returns the length of the copied string, without null-terminator.
+ */
+static unsigned long utf16_copy_to_buf(efi_char16_t *dst, const efi_char16_t *src,
+				       unsigned long bytes)
+{
+	return utf16_strlcpy(dst, src, bytes / sizeof(src[0]));
+}
+
+
+/* -- Qualcomm "uefisecapp" interface definitions. -------------------------- */
+
+#define QSEE_UEFISEC_APP_NAME			"qcom.tz.uefisecapp"
+
+#define QSEE_CMD_UEFI(x)			(0x8000 | (x))
+#define QSEE_CMD_UEFI_GET_VARIABLE		QSEE_CMD_UEFI(0)
+#define QSEE_CMD_UEFI_SET_VARIABLE		QSEE_CMD_UEFI(1)
+#define QSEE_CMD_UEFI_GET_NEXT_VARIABLE		QSEE_CMD_UEFI(2)
+#define QSEE_CMD_UEFI_QUERY_VARIABLE_INFO	QSEE_CMD_UEFI(3)
+
+/**
+ * struct qsee_req_uefi_get_variable - Request for GetVariable command.
+ * @command_id:  The ID of the command. Must be %QSEE_CMD_UEFI_GET_VARIABLE.
+ * @length:      Length of the request in bytes, including this struct and any
+ *               parameters (name, GUID) stored after it as well as any padding
+ *               thereof for alignment.
+ * @name_offset: Offset from the start of this struct to where the variable
+ *               name is stored (as utf-16 string), in bytes.
+ * @name_size:   Size of the name parameter in bytes, including null-terminator.
+ * @guid_offset: Offset from the start of this struct to where the GUID
+ *               parameter is stored, in bytes.
+ * @guid_size:   Size of the GUID parameter in bytes, i.e. sizeof(efi_guid_t).
+ * @data_size:   Size of the output buffer, in bytes.
+ */
+struct qsee_req_uefi_get_variable {
+	u32 command_id;
+	u32 length;
+	u32 name_offset;
+	u32 name_size;
+	u32 guid_offset;
+	u32 guid_size;
+	u32 data_size;
+} __packed;
+
+/**
+ * struct qsee_rsp_uefi_get_variable - Response for GetVariable command.
+ * @command_id:  The ID of the command. Should be %QSEE_CMD_UEFI_GET_VARIABLE.
+ * @length:      Length of the response in bytes, including this struct and the
+ *               returned data.
+ * @status:      Status of this command.
+ * @attributes:  EFI variable attributes.
+ * @data_offset: Offset from the start of this struct to where the data is
+ *               stored, in bytes.
+ * @data_size:   Size of the returned data, in bytes. In case status indicates
+ *               that the buffer is too small, this will be the size required
+ *               to store the EFI variable data.
+ */
+struct qsee_rsp_uefi_get_variable {
+	u32 command_id;
+	u32 length;
+	u32 status;
+	u32 attributes;
+	u32 data_offset;
+	u32 data_size;
+} __packed;
+
+/**
+ * struct qsee_req_uefi_set_variable - Request for the SetVariable command.
+ * @command_id:  The ID of the command. Must be %QSEE_CMD_UEFI_SET_VARIABLE.
+ * @length:      Length of the request in bytes, including this struct and any
+ *               parameters (name, GUID, data) stored after it as well as any
+ *               padding thereof required for alignment.
+ * @name_offset: Offset from the start of this struct to where the variable
+ *               name is stored (as utf-16 string), in bytes.
+ * @name_size:   Size of the name parameter in bytes, including null-terminator.
+ * @guid_offset: Offset from the start of this struct to where the GUID
+ *               parameter is stored, in bytes.
+ * @guid_size:   Size of the GUID parameter in bytes, i.e. sizeof(efi_guid_t).
+ * @attributes:  The EFI variable attributes to set for this variable.
+ * @data_offset: Offset from the start of this struct to where the EFI variable
+ *               data is stored, in bytes.
+ * @data_size:   Size of EFI variable data, in bytes.
+ *
+ */
+struct qsee_req_uefi_set_variable {
+	u32 command_id;
+	u32 length;
+	u32 name_offset;
+	u32 name_size;
+	u32 guid_offset;
+	u32 guid_size;
+	u32 attributes;
+	u32 data_offset;
+	u32 data_size;
+} __packed;
+
+/**
+ * struct qsee_rsp_uefi_set_variable - Response for the SetVariable command.
+ * @command_id:  The ID of the command. Should be %QSEE_CMD_UEFI_SET_VARIABLE.
+ * @length:      The length of this response, i.e. the size of this struct in
+ *               bytes.
+ * @status:      Status of this command.
+ * @_unknown1:   Unknown response field.
+ * @_unknown2:   Unknown response field.
+ */
+struct qsee_rsp_uefi_set_variable {
+	u32 command_id;
+	u32 length;
+	u32 status;
+	u32 _unknown1;
+	u32 _unknown2;
+} __packed;
+
+/**
+ * struct qsee_req_uefi_get_next_variable - Request for the
+ * GetNextVariableName command.
+ * @command_id:  The ID of the command. Must be
+ *               %QSEE_CMD_UEFI_GET_NEXT_VARIABLE.
+ * @length:      Length of the request in bytes, including this struct and any
+ *               parameters (name, GUID) stored after it as well as any padding
+ *               thereof for alignment.
+ * @guid_offset: Offset from the start of this struct to where the GUID
+ *               parameter is stored, in bytes.
+ * @guid_size:   Size of the GUID parameter in bytes, i.e. sizeof(efi_guid_t).
+ * @name_offset: Offset from the start of this struct to where the variable
+ *               name is stored (as utf-16 string), in bytes.
+ * @name_size:   Size of the name parameter in bytes, including null-terminator.
+ */
+struct qsee_req_uefi_get_next_variable {
+	u32 command_id;
+	u32 length;
+	u32 guid_offset;
+	u32 guid_size;
+	u32 name_offset;
+	u32 name_size;
+} __packed;
+
+/**
+ * struct qsee_rsp_uefi_get_next_variable - Response for the
+ * GetNextVariableName command.
+ * @command_id:  The ID of the command. Should be
+ *               %QSEE_CMD_UEFI_GET_NEXT_VARIABLE.
+ * @length:      Length of the response in bytes, including this struct and any
+ *               parameters (name, GUID) stored after it as well as any padding
+ *               thereof for alignment.
+ * @status:      Status of this command.
+ * @guid_size:   Size of the GUID parameter in bytes, i.e. sizeof(efi_guid_t).
+ * @name_offset: Offset from the start of this struct to where the variable
+ *               name is stored (as utf-16 string), in bytes.
+ * @name_size:   Size of the name parameter in bytes, including null-terminator.
+ */
+struct qsee_rsp_uefi_get_next_variable {
+	u32 command_id;
+	u32 length;
+	u32 status;
+	u32 guid_offset;
+	u32 guid_size;
+	u32 name_offset;
+	u32 name_size;
+} __packed;
+
+/**
+ * struct qsee_req_uefi_query_variable_info - Response for the
+ * GetNextVariableName command.
+ * @command_id: The ID of the command. Must be
+ *              %QSEE_CMD_UEFI_QUERY_VARIABLE_INFO.
+ * @length:     The length of this request, i.e. the size of this struct in
+ *              bytes.
+ * @attributes: The storage attributes to query the info for.
+ */
+struct qsee_req_uefi_query_variable_info {
+	u32 command_id;
+	u32 length;
+	u32 attributes;
+} __packed;
+
+/**
+ * struct qsee_rsp_uefi_query_variable_info - Response for the
+ * GetNextVariableName command.
+ * @command_id:        The ID of the command. Must be
+ *                     %QSEE_CMD_UEFI_QUERY_VARIABLE_INFO.
+ * @length:            The length of this response, i.e. the size of this
+ *                     struct in bytes.
+ * @status:            Status of this command.
+ * @_pad:              Padding.
+ * @storage_space:     Full storage space size, in bytes.
+ * @remaining_space:   Free storage space available, in bytes.
+ * @max_variable_size: Maximum variable data size, in bytes.
+ */
+struct qsee_rsp_uefi_query_variable_info {
+	u32 command_id;
+	u32 length;
+	u32 status;
+	u32 _pad;
+	u64 storage_space;
+	u64 remaining_space;
+	u64 max_variable_size;
+} __packed;
+
+
+/* -- UEFI app interface. --------------------------------------------------- */
+
+struct qcuefi_client {
+	struct device *dev;
+	struct qseecom_device *qsee;
+	struct qseecom_dma dma;
+	struct efivars efivars;
+	u32 app_id;
+};
+
+static efi_status_t qsee_uefi_status_to_efi(u32 status)
+{
+	u64 category = status & 0xf0000000;
+	u64 code = status & 0x0fffffff;
+
+	return category << (BITS_PER_LONG - 32) | code;
+}
+
+static efi_status_t qsee_uefi_get_variable(struct qcuefi_client *qcuefi, const efi_char16_t *name,
+					   const efi_guid_t *guid, u32 *attributes,
+					   unsigned long *data_size, void *data)
+{
+	struct qsee_req_uefi_get_variable *req_data;
+	struct qsee_rsp_uefi_get_variable *rsp_data;
+	struct qseecom_dma dma_req;
+	struct qseecom_dma dma_rsp;
+	unsigned long name_size = utf16_strsize(name);
+	unsigned long buffer_size = *data_size;
+	unsigned long size;
+	efi_status_t efi_status;
+	int status;
+
+	/* Validation: We need a name and GUID. */
+	if (!name || !guid)
+		return EFI_INVALID_PARAMETER;
+
+	/* Validation: We need a buffer if the buffer_size is nonzero. */
+	if (buffer_size && !data)
+		return EFI_INVALID_PARAMETER;
+
+	/* Compute required size (upper limit with alignments). */
+	size = sizeof(*req_data) + sizeof(*guid) + name_size  /* Inputs. */
+	       + sizeof(*rsp_data) + buffer_size              /* Outputs. */
+	       + 2 * (QSEECOM_DMA_ALIGNMENT - 1)              /* Input parameter alignments. */
+	       + 1 * (QSEECOM_DMA_ALIGNMENT - 1);             /* Output parameter alignments. */
+
+	/* Make sure we have enough DMA memory. */
+	status = qseecom_dma_realloc(qcuefi->dev, &qcuefi->dma, size, GFP_KERNEL);
+	if (status)
+		return EFI_OUT_OF_RESOURCES;
+
+	/* Align request struct. */
+	qseecom_dma_aligned(&qcuefi->dma, &dma_req, 0);
+	req_data = dma_req.virt;
+
+	/* Set up request data. */
+	req_data->command_id = QSEE_CMD_UEFI_GET_VARIABLE;
+	req_data->data_size = buffer_size;
+	req_data->name_offset = sizeof(*req_data);
+	req_data->name_size = name_size;
+	req_data->guid_offset = QSEECOM_DMA_ALIGN(req_data->name_offset + name_size);
+	req_data->guid_size = sizeof(*guid);
+	req_data->length = req_data->guid_offset + req_data->guid_size;
+
+	dma_req.size = req_data->length;
+
+	/* Copy request parameters. */
+	utf16_copy_to_buf(dma_req.virt + req_data->name_offset, name, name_size);
+	memcpy(dma_req.virt + req_data->guid_offset, guid, req_data->guid_size);
+
+	/* Align response struct. */
+	qseecom_dma_aligned(&qcuefi->dma, &dma_rsp, req_data->length);
+	rsp_data = dma_rsp.virt;
+
+	/* Perform SCM call. */
+	status = qseecom_app_send(qcuefi->qsee, qcuefi->app_id, &dma_req, &dma_rsp);
+
+	/* Check for errors and validate. */
+	if (status)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->command_id != QSEE_CMD_UEFI_GET_VARIABLE)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->length < sizeof(*rsp_data) || rsp_data->length > dma_rsp.size)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->status) {
+		dev_dbg(qcuefi->dev, "%s: uefisecapp error: 0x%x\n", __func__, rsp_data->status);
+		efi_status = qsee_uefi_status_to_efi(rsp_data->status);
+
+		/* Update size and attributes in case buffer is too small. */
+		if (efi_status == EFI_BUFFER_TOO_SMALL) {
+			*data_size = rsp_data->data_size;
+			if (attributes)
+				*attributes = rsp_data->attributes;
+		}
+
+		return efi_status;
+	}
+
+	if (rsp_data->data_offset + rsp_data->data_size > rsp_data->length)
+		return EFI_DEVICE_ERROR;
+
+	/* Set attributes and data size even if buffer is too small. */
+	*data_size = rsp_data->data_size;
+	if (attributes)
+		*attributes = rsp_data->attributes;
+
+	/*
+	 * If we have a buffer size of zero and no buffer, just return
+	 * attributes and required size.
+	 */
+	if (buffer_size == 0 && !data)
+		return EFI_SUCCESS;
+
+	/* Validate output buffer size. */
+	if (buffer_size < rsp_data->data_size)
+		return EFI_BUFFER_TOO_SMALL;
+
+	/* Copy to output buffer. Note: We're guaranteed to have one at this point. */
+	memcpy(data, dma_rsp.virt + rsp_data->data_offset, rsp_data->data_size);
+	return EFI_SUCCESS;
+}
+
+static efi_status_t qsee_uefi_set_variable(struct qcuefi_client *qcuefi, const efi_char16_t *name,
+					   const efi_guid_t *guid, u32 attributes,
+					   unsigned long data_size, const void *data)
+{
+	struct qsee_req_uefi_set_variable *req_data;
+	struct qsee_rsp_uefi_set_variable *rsp_data;
+	struct qseecom_dma dma_req;
+	struct qseecom_dma dma_rsp;
+	unsigned long name_size = utf16_strsize(name);
+	unsigned long size;
+	int status;
+
+	/* Validate inputs. */
+	if (!name || !guid)
+		return EFI_INVALID_PARAMETER;
+
+	/*
+	 * Make sure we have some data if data_size is nonzero. Note: Using a
+	 * size of zero is valid and deletes the variable.
+	 */
+	if (data_size && !data)
+		return EFI_INVALID_PARAMETER;
+
+	/* Compute required size (upper limit with alignments). */
+	size = sizeof(*req_data) + name_size + sizeof(*guid) + data_size  /* Inputs. */
+	       + sizeof(*rsp_data)                            /* Outputs. */
+	       + 2 * (QSEECOM_DMA_ALIGNMENT - 1)              /* Input parameter alignments. */
+	       + 1 * (QSEECOM_DMA_ALIGNMENT - 1);             /* Output parameter alignments. */
+
+	/* Make sure we have enough DMA memory. */
+	status = qseecom_dma_realloc(qcuefi->dev, &qcuefi->dma, size, GFP_KERNEL);
+	if (status)
+		return EFI_OUT_OF_RESOURCES;
+
+	/* Align request struct. */
+	qseecom_dma_aligned(&qcuefi->dma, &dma_req, 0);
+	req_data = dma_req.virt;
+
+	/* Set up request data. */
+	req_data->command_id = QSEE_CMD_UEFI_SET_VARIABLE;
+	req_data->attributes = attributes;
+	req_data->name_offset = sizeof(*req_data);
+	req_data->name_size = name_size;
+	req_data->guid_offset = QSEECOM_DMA_ALIGN(req_data->name_offset + name_size);
+	req_data->guid_size = sizeof(*guid);
+	req_data->data_offset = req_data->guid_offset + req_data->guid_size;
+	req_data->data_size = data_size;
+	req_data->length = req_data->data_offset + data_size;
+
+	/* Copy request parameters. */
+	utf16_copy_to_buf(dma_req.virt + req_data->name_offset, name, req_data->name_size);
+	memcpy(dma_req.virt + req_data->guid_offset, guid, req_data->guid_size);
+
+	if (data_size)
+		memcpy(dma_req.virt + req_data->data_offset, data, req_data->data_size);
+
+	/* Align response struct. */
+	qseecom_dma_aligned(&qcuefi->dma, &dma_rsp, req_data->length);
+	rsp_data = dma_rsp.virt;
+
+	/* Perform SCM call. */
+	dma_req.size = req_data->length;
+	dma_rsp.size = sizeof(*rsp_data);
+
+	status = qseecom_app_send(qcuefi->qsee, qcuefi->app_id, &dma_req, &dma_rsp);
+
+	/* Check for errors and validate. */
+	if (status)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->command_id != QSEE_CMD_UEFI_SET_VARIABLE)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->length < sizeof(*rsp_data) || rsp_data->length > dma_rsp.size)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->status) {
+		dev_dbg(qcuefi->dev, "%s: uefisecapp error: 0x%x\n", __func__, rsp_data->status);
+		return qsee_uefi_status_to_efi(rsp_data->status);
+	}
+
+	return EFI_SUCCESS;
+}
+
+static efi_status_t qsee_uefi_get_next_variable(struct qcuefi_client *qcuefi,
+						unsigned long *name_size, efi_char16_t *name,
+						efi_guid_t *guid)
+{
+	struct qsee_req_uefi_get_next_variable *req_data;
+	struct qsee_rsp_uefi_get_next_variable *rsp_data;
+	struct qseecom_dma dma_req;
+	struct qseecom_dma dma_rsp;
+	unsigned long size;
+	efi_status_t efi_status;
+	int status;
+
+	/* We need some buffers. */
+	if (!name_size || !name || !guid)
+		return EFI_INVALID_PARAMETER;
+
+	/* There needs to be at least a single null-character. */
+	if (*name_size == 0)
+		return EFI_INVALID_PARAMETER;
+
+	/* Compute required size (upper limit with alignments). */
+	size = sizeof(*req_data) + sizeof(*guid) + *name_size    /* Inputs. */
+	       + sizeof(*rsp_data) + sizeof(*guid) + *name_size  /* Outputs. */
+	       + 2 * (QSEECOM_DMA_ALIGNMENT - 1)                 /* Input parameter alignments. */
+	       + 1 * (QSEECOM_DMA_ALIGNMENT - 1);                /* Output parameter alignments. */
+
+	/* Make sure we have enough DMA memory. */
+	status = qseecom_dma_realloc(qcuefi->dev, &qcuefi->dma, size, GFP_KERNEL);
+	if (status)
+		return EFI_OUT_OF_RESOURCES;
+
+	/* Align request struct. */
+	qseecom_dma_aligned(&qcuefi->dma, &dma_req, 0);
+	req_data = dma_req.virt;
+
+	/* Set up request data. */
+	req_data->command_id = QSEE_CMD_UEFI_GET_NEXT_VARIABLE;
+	req_data->guid_offset = QSEECOM_DMA_ALIGN(sizeof(*req_data));
+	req_data->guid_size = sizeof(*guid);
+	req_data->name_offset = req_data->guid_offset + req_data->guid_size;
+	req_data->name_size = *name_size;
+	req_data->length = req_data->name_offset + req_data->name_size;
+
+	dma_req.size = req_data->length;
+
+	/* Copy request parameters. */
+	memcpy(dma_req.virt + req_data->guid_offset, guid, req_data->guid_size);
+	utf16_copy_to_buf(dma_req.virt + req_data->name_offset, name, *name_size);
+
+	/* Align response struct. */
+	qseecom_dma_aligned(&qcuefi->dma, &dma_rsp, req_data->length);
+	rsp_data = dma_rsp.virt;
+
+	/* Perform SCM call. */
+	status = qseecom_app_send(qcuefi->qsee, qcuefi->app_id, &dma_req, &dma_rsp);
+
+	/* Check for errors and validate. */
+	if (status)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->command_id != QSEE_CMD_UEFI_GET_NEXT_VARIABLE)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->length < sizeof(*rsp_data) || rsp_data->length > dma_rsp.size)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->status) {
+		dev_dbg(qcuefi->dev, "%s: uefisecapp error: 0x%x\n", __func__, rsp_data->status);
+		efi_status = qsee_uefi_status_to_efi(rsp_data->status);
+
+		/* Update size with required size in case buffer is too small. */
+		if (efi_status == EFI_BUFFER_TOO_SMALL)
+			*name_size = rsp_data->name_size;
+
+		return efi_status;
+	}
+
+	if (rsp_data->name_offset + rsp_data->name_size > rsp_data->length)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->guid_offset + rsp_data->guid_size > rsp_data->length)
+		return EFI_DEVICE_ERROR;
+
+	if (rsp_data->name_size > *name_size) {
+		*name_size = rsp_data->name_size;
+		return EFI_BUFFER_TOO_SMALL;
+	}
+
+	if (rsp_data->guid_size != sizeof(*guid))
+		return EFI_DEVICE_ERROR;
+
+	/* Copy response fields. */
+	memcpy(guid, dma_rsp.virt + rsp_data->guid_offset, rsp_data->guid_size);
+	utf16_copy_to_buf(name, dma_rsp.virt + rsp_data->name_offset, rsp_data->name_size);
+	*name_size = rsp_data->name_size;
+
+	return 0;
+}
+
+
+/* -- Global efivar interface. ---------------------------------------------- */
+
+static struct qcuefi_client *__qcuefi;
+static DEFINE_MUTEX(__qcuefi_lock);
+
+static int qcuefi_set_reference(struct qcuefi_client *qcuefi)
+{
+	mutex_lock(&__qcuefi_lock);
+
+	if (qcuefi && __qcuefi) {
+		mutex_unlock(&__qcuefi_lock);
+		return -EEXIST;
+	}
+
+	__qcuefi = qcuefi;
+
+	mutex_unlock(&__qcuefi_lock);
+	return 0;
+}
+
+static struct qcuefi_client *qcuefi_acquire(void)
+{
+	mutex_lock(&__qcuefi_lock);
+	return __qcuefi;
+}
+
+static void qcuefi_release(void)
+{
+	mutex_unlock(&__qcuefi_lock);
+}
+
+static efi_status_t qcuefi_get_variable(efi_char16_t *name, efi_guid_t *vendor, u32 *attr,
+					unsigned long *data_size, void *data)
+{
+	struct qcuefi_client *qcuefi;
+	efi_status_t status;
+
+	qcuefi = qcuefi_acquire();
+	if (!qcuefi)
+		return EFI_NOT_READY;
+
+	status = qsee_uefi_get_variable(qcuefi, name, vendor, attr, data_size, data);
+
+	qcuefi_release();
+	return status;
+}
+
+static efi_status_t qcuefi_set_variable(efi_char16_t *name, efi_guid_t *vendor,
+					u32 attr, unsigned long data_size, void *data)
+{
+	struct qcuefi_client *qcuefi;
+	efi_status_t status;
+
+	qcuefi = qcuefi_acquire();
+	if (!qcuefi)
+		return EFI_NOT_READY;
+
+	status = qsee_uefi_set_variable(qcuefi, name, vendor, attr, data_size, data);
+
+	qcuefi_release();
+	return status;
+}
+
+static efi_status_t qcuefi_get_next_variable(unsigned long *name_size, efi_char16_t *name,
+					     efi_guid_t *vendor)
+{
+	struct qcuefi_client *qcuefi;
+	efi_status_t status;
+
+	qcuefi = qcuefi_acquire();
+	if (!qcuefi)
+		return EFI_NOT_READY;
+
+	status = qsee_uefi_get_next_variable(qcuefi, name_size, name, vendor);
+
+	qcuefi_release();
+	return status;
+}
+
+static const struct efivar_operations qcom_efivar_ops = {
+	.get_variable = qcuefi_get_variable,
+	.set_variable = qcuefi_set_variable,
+	.get_next_variable = qcuefi_get_next_variable,
+};
+
+
+/* -- Driver setup. --------------------------------------------------------- */
+
+static int qcom_uefisecapp_probe(struct platform_device *pdev)
+{
+	struct qcuefi_client *qcuefi;
+	int status;
+
+	/* Allocate driver data. */
+	qcuefi = devm_kzalloc(&pdev->dev, sizeof(*qcuefi), GFP_KERNEL);
+	if (!qcuefi)
+		return -ENOMEM;
+
+	qcuefi->dev = &pdev->dev;
+
+	/* We expect the parent to be the QSEECOM device. */
+	qcuefi->qsee = dev_get_drvdata(pdev->dev.parent);
+	if (!qcuefi->qsee)
+		return -EINVAL;
+
+	/* Get application id for uefisecapp. */
+	status = qseecom_app_get_id(qcuefi->qsee, QSEE_UEFISEC_APP_NAME, &qcuefi->app_id);
+	if (status) {
+		dev_err(&pdev->dev, "failed to query app ID: %d\n", status);
+		return status;
+	}
+
+	/* Set up DMA. One page should be plenty to start with. */
+	if (dma_set_mask(&pdev->dev, DMA_BIT_MASK(64))) {
+		dev_warn(&pdev->dev, "no suitable DMA available\n");
+		return -EFAULT;
+	}
+
+	status = qseecom_dma_alloc(&pdev->dev, &qcuefi->dma, PAGE_SIZE, GFP_KERNEL);
+	if (status)
+		return status;
+
+	/* Register global reference. */
+	platform_set_drvdata(pdev, qcuefi);
+	status = qcuefi_set_reference(qcuefi);
+	if (status)
+		goto free;
+
+	/* Register efivar ops. */
+	status = efivars_register(&qcuefi->efivars, &qcom_efivar_ops);
+	if (status)
+		goto clear_reference;
+
+	return 0;
+
+clear_reference:
+	qcuefi_set_reference(NULL);
+free:
+	qseecom_dma_free(qcuefi->dev, &qcuefi->dma);
+	return status;
+}
+
+static int qcom_uefisecapp_remove(struct platform_device *pdev)
+{
+	struct qcuefi_client *qcuefi = platform_get_drvdata(pdev);
+
+	/* Unregister efivar ops. */
+	efivars_unregister(&qcuefi->efivars);
+
+	/* Block on pending calls and unregister global reference. */
+	qcuefi_set_reference(NULL);
+
+	/* Free remaining resources. */
+	qseecom_dma_free(qcuefi->dev, &qcuefi->dma);
+
+	return 0;
+}
+
+static struct platform_driver qcom_uefisecapp_driver = {
+	.probe = qcom_uefisecapp_probe,
+	.remove = qcom_uefisecapp_remove,
+	.driver = {
+		.name = "qcom_qseecom_uefisecapp",
+		.probe_type = PROBE_PREFER_ASYNCHRONOUS,
+	},
+};
+module_platform_driver(qcom_uefisecapp_driver);
+
+MODULE_AUTHOR("Maximilian Luz <luzmaximilian@gmail.com>");
+MODULE_DESCRIPTION("Client driver for Qualcomm SEE UEFI Secure App");
+MODULE_LICENSE("GPL");
+MODULE_ALIAS("platform:qcom_qseecom_uefisecapp");
-- 
2.39.0

Re: [PATCH v2 3/4] dt-bindings: firmware: Add Qualcomm QSEECOM interface

[Rob Herring]

On Fri, Jan 27, 2023 at 07:46:49PM +0100, Maximilian Luz wrote:
> Add bindings for the Qualcomm Secure Execution Environment interface
> (QSEECOM).
> 
> Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
> ---
> 
> Changes in v2:
>  - Replaces uefisecapp bindings.
>  - Fix various dt-checker complaints.
> 
> ---
>  .../bindings/firmware/qcom,qseecom.yaml       | 49 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 50 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
> 
> diff --git a/Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml b/Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
> new file mode 100644
> index 000000000000..540a604f81bc
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
> @@ -0,0 +1,49 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/firmware/qcom,qseecom.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Qualcomm Secure Execution Environment Communication Interface
> +
> +maintainers:
> +  - Maximilian Luz <luzmaximilian@gmail.com>
> +
> +description: |
> +  QSEECOM provides an interface to Qualcomm's Secure Execution Environment
> +  (SEE) running in the Trust Zone via SCM calls. In particular, it allows

SCM is SMCCC or something else?

> +  communication with secure applications running therein.
> +
> +  Applications running in this environment can, for example, include
> +  'uefisecapp', which is required for accessing UEFI variables on certain
> +  systems as these cannot be accessed directly.
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - qcom,qseecom-sc8280xp
> +      - const: qcom,qseecom
> +
> +  qcom,scm:
> +    $ref: '/schemas/types.yaml#/definitions/phandle'
> +    description:
> +      A phandle pointing to the QCOM SCM device (see ./qcom,scm.yaml).
> +
> +required:
> +  - compatible
> +  - qcom,scm
> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    firmware {
> +        scm {
> +            compatible = "qcom,scm-sc8280xp", "qcom,scm";
> +        };
> +        qseecom {
> +            compatible = "qcom,qseecom-sc8280xp", "qcom,qseecom";
> +            qcom,scm = <&scm>;

Why do you need this in DT? If you already know you have a firmware 
interface (via "qcom,scm"), then query the firmware to see if the SEE is 
there.

Rob

Re: [PATCH v2 3/4] dt-bindings: firmware: Add Qualcomm QSEECOM interface

[Maximilian Luz]

On 1/30/23 22:05, Rob Herring wrote:
> On Fri, Jan 27, 2023 at 07:46:49PM +0100, Maximilian Luz wrote:
>> Add bindings for the Qualcomm Secure Execution Environment interface
>> (QSEECOM).
>>
>> Signed-off-by: Maximilian Luz <luzmaximilian@gmail.com>
>> ---
>>
>> Changes in v2:
>>   - Replaces uefisecapp bindings.
>>   - Fix various dt-checker complaints.
>>
>> ---
>>   .../bindings/firmware/qcom,qseecom.yaml       | 49 +++++++++++++++++++
>>   MAINTAINERS                                   |  1 +
>>   2 files changed, 50 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml b/Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
>> new file mode 100644
>> index 000000000000..540a604f81bc
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/firmware/qcom,qseecom.yaml
>> @@ -0,0 +1,49 @@
>> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/firmware/qcom,qseecom.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Qualcomm Secure Execution Environment Communication Interface
>> +
>> +maintainers:
>> +  - Maximilian Luz <luzmaximilian@gmail.com>
>> +
>> +description: |
>> +  QSEECOM provides an interface to Qualcomm's Secure Execution Environment
>> +  (SEE) running in the Trust Zone via SCM calls. In particular, it allows
> 
> SCM is SMCCC or something else?

It's whatever qcom-scm.c uses. I'm not too familiar with the specifics,
so maybe someone else can answer this better.

>> +  communication with secure applications running therein.
>> +
>> +  Applications running in this environment can, for example, include
>> +  'uefisecapp', which is required for accessing UEFI variables on certain
>> +  systems as these cannot be accessed directly.
>> +
>> +properties:
>> +  compatible:
>> +    items:
>> +      - enum:
>> +          - qcom,qseecom-sc8280xp
>> +      - const: qcom,qseecom
>> +
>> +  qcom,scm:
>> +    $ref: '/schemas/types.yaml#/definitions/phandle'
>> +    description:
>> +      A phandle pointing to the QCOM SCM device (see ./qcom,scm.yaml).
>> +
>> +required:
>> +  - compatible
>> +  - qcom,scm
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    firmware {
>> +        scm {
>> +            compatible = "qcom,scm-sc8280xp", "qcom,scm";
>> +        };
>> +        qseecom {
>> +            compatible = "qcom,qseecom-sc8280xp", "qcom,qseecom";
>> +            qcom,scm = <&scm>;
> 
> Why do you need this in DT? If you already know you have a firmware
> interface (via "qcom,scm"), then query the firmware to see if the SEE is
> there.

Unfortunately I don't know of any way to query this, but please let me
know if you do.

As I've briefly mentioned in the cover letter: There are two interfaces
to manage secure apps. QSEECOM (on older and current-gen laptop devices)
and scminvoke (on newer and some current-gen mobile devices if I
understood right). ACPI also uses a separate device for this
(QCOM0476), so it seemed like the best option to follow that.

Ideally, scminvoke would be preferred since that can be integrated as
TEE driver, but I've been told that on platforms where apps (like
uefisecapp) are loaded via QSEECOM by firmware, we can only use QSEECOM
to communicate with those.

Regards,
Max