From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Arve=20Hj=C3=B8nnev=C3=A5g?= <arve@android.com>
Date: Thu, 11 Jun 2015 19:34:28 -0700
Subject: [PATCH] trusty: Select api version

Select api version in probe, and store it in trusty_state.
This enables new return codes from trusty, and will later be used
to enable a nop stdcall that does not take smc_lock.

Change-Id: I8011325265da818725ef65f094bf820402878eb5
---
 drivers/trusty/trusty.c       | 35 +++++++++++++++++++++++++++++++++++
 include/linux/trusty/smcall.h | 19 +++++++++++++++++++
 include/linux/trusty/trusty.h |  1 +
 3 files changed, 55 insertions(+)

diff --git a/drivers/trusty/trusty.c b/drivers/trusty/trusty.c
index 16c595bf5e29..fcdbba518797 100644
--- a/drivers/trusty/trusty.c
+++ b/drivers/trusty/trusty.c
@@ -29,6 +29,7 @@ struct trusty_state {
 	struct mutex smc_lock;
 	struct atomic_notifier_head notifier;
 	char *version_str;
+	u32 api_version;
 };
 
 #ifdef CONFIG_ARM64
@@ -265,6 +266,35 @@ static void trusty_init_version(struct trusty_state *s, struct device *dev)
 	dev_err(dev, "failed to get version: %d\n", ret);
 }
 
+u32 trusty_get_api_version(struct device *dev)
+{
+	struct trusty_state *s = platform_get_drvdata(to_platform_device(dev));
+
+	return s->api_version;
+}
+EXPORT_SYMBOL(trusty_get_api_version);
+
+static int trusty_init_api_version(struct trusty_state *s, struct device *dev)
+{
+	u32 api_version;
+	api_version = trusty_fast_call32(dev, SMC_FC_API_VERSION,
+					 TRUSTY_API_VERSION_CURRENT, 0, 0);
+	if (api_version == SM_ERR_UNDEFINED_SMC)
+		api_version = 0;
+
+	if (api_version > TRUSTY_API_VERSION_CURRENT) {
+		dev_err(dev, "unsupported api version %u > %u\n",
+			api_version, TRUSTY_API_VERSION_CURRENT);
+		return -EINVAL;
+	}
+
+	dev_info(dev, "selected api version: %u (requested %u)\n",
+		 api_version, TRUSTY_API_VERSION_CURRENT);
+	s->api_version = api_version;
+
+	return 0;
+}
+
 static int trusty_probe(struct platform_device *pdev)
 {
 	int ret;
@@ -287,6 +317,10 @@ static int trusty_probe(struct platform_device *pdev)
 
 	trusty_init_version(s, &pdev->dev);
 
+	ret = trusty_init_api_version(s, &pdev->dev);
+	if (ret < 0)
+		goto err_api_version;
+
 	ret = of_platform_populate(pdev->dev.of_node, NULL, NULL, &pdev->dev);
 	if (ret < 0) {
 		dev_err(&pdev->dev, "Failed to add children: %d\n", ret);
@@ -296,6 +330,7 @@ static int trusty_probe(struct platform_device *pdev)
 	return 0;
 
 err_add_children:
+err_api_version:
 	if (s->version_str) {
 		device_remove_file(&pdev->dev, &dev_attr_trusty_version);
 		kfree(s->version_str);
diff --git a/include/linux/trusty/smcall.h b/include/linux/trusty/smcall.h
index a2be2e3579f3..cdb4eccd7bc3 100644
--- a/include/linux/trusty/smcall.h
+++ b/include/linux/trusty/smcall.h
@@ -78,6 +78,25 @@
 #define SMC_FC_AARCH_SWITCH	SMC_FASTCALL_NR (SMC_ENTITY_SECURE_MONITOR, 9)
 #define SMC_FC_GET_VERSION_STR	SMC_FASTCALL_NR (SMC_ENTITY_SECURE_MONITOR, 10)
 
+/**
+ * SMC_FC_API_VERSION - Find and select supported API version.
+ *
+ * @r1: Version supported by client.
+ *
+ * Returns version supported by trusty.
+ *
+ * If multiple versions are supported, the client should start by calling
+ * SMC_FC_API_VERSION with the largest version it supports. Trusty will then
+ * return a version it supports. If the client does not support the version
+ * returned by trusty and the version returned is less than the version
+ * requested, repeat the call with the largest supported version less than the
+ * last returned version.
+ *
+ * This call must be made before any calls that are affected by the api version.
+ */
+#define TRUSTY_API_VERSION_CURRENT	(0)
+#define SMC_FC_API_VERSION	SMC_FASTCALL_NR (SMC_ENTITY_SECURE_MONITOR, 11)
+
 /* TRUSTED_OS entity calls */
 #define SMC_SC_VIRTIO_GET_DESCR	SMC_STDCALL_NR(SMC_ENTITY_TRUSTED_OS, 20)
 #define SMC_SC_VIRTIO_START	SMC_STDCALL_NR(SMC_ENTITY_TRUSTED_OS, 21)
diff --git a/include/linux/trusty/trusty.h b/include/linux/trusty/trusty.h
index d084d9d68a7b..24fe2101a528 100644
--- a/include/linux/trusty/trusty.h
+++ b/include/linux/trusty/trusty.h
@@ -56,6 +56,7 @@ int trusty_call_notifier_register(struct device *dev,
 int trusty_call_notifier_unregister(struct device *dev,
 				    struct notifier_block *n);
 const char *trusty_version_str_get(struct device *dev);
+u32 trusty_get_api_version(struct device *dev);
 
 struct ns_mem_page_info {
 	uint64_t attr;
-- 
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